JP7836744B2 - Method for converting ethanol, method for producing hydrocarbons, method for producing propylene, method for producing aromatic compounds, and apparatus for converting ethanol. - Google Patents

Description

This invention relates to a method for converting ethanol, a method for producing hydrocarbons, a method for producing propylene, a method for producing aromatic compounds, and an apparatus for converting ethanol.

Lower olefins and aromatic compounds are important raw materials in the chemical industry, and propylene in particular is expected to see increased demand, leading to extensive development and improvement of various manufacturing methods. Among these, a common method for producing propylene involves contacting naphtha or olefins with a catalyst using zeolite as the active species.

Beyond olefins, the recent rise in environmental awareness has led to increased attention on the production of lower olefins and aromatic compounds using biomass-derived alcohols as raw materials. In particular, since ethanol is a compound for which a biomass-based production method has been established, the early development of efficient ethanol conversion methods is highly anticipated.

For example, Patent Document 1 discloses a method for converting olefins or alcohols. Patent Document 2 discloses a pentasil-type zeolite as a catalyst. Patent Document 3 discloses a zinc oxide cerium-supported zeolite as a catalyst. For example, Patent Document 4 shows a method for producing lower olefins using an oxygen-containing compound (oxygeneate) and an olefin with four or more carbon atoms as raw materials. Patent Document 5 shows a method for producing lower olefins using a lower alcohol and naphtha as raw materials.

International Publication No. 2014/025021 International Publication No. 2015/029355 Chinese Patent Application Publication No. 110560155 U.S. Patent Application Publication No. 2014/0018593 Chinese Patent Application Publication No. 110871107

When converting ethanol to hydrocarbons such as propylene and aromatic compounds, the reaction process involves the dehydration of ethanol to produce ethylene. In the conversion of ethanol to olefins, the dehydration reaction of ethanol occurs as described above. However, this dehydration reaction is endothermic, causing a decrease in the reactor temperature. This makes temperature control difficult, and in some cases, requires significant heat to be applied to the reactor. Furthermore, a decrease in reaction temperature leads to a reduction in the yield of the target compound, the light olefin. On the other hand, in reactions where ethylene is produced and then converted to propylene or aromatic compounds, the reaction is exothermic. In some cases, this can lead to a high reactor temperature, increasing the amount of by-products such as coke, and thus reducing the yield of the target compound.

Patent documents 1 to 3 disclose techniques for converting each raw material into the target olefin using a zeolite catalyst, but these techniques involve significant heat absorption and exothermic reactions, making temperature control difficult.
Patent documents 4 and 5 disclose a thermal neutralization technique that utilizes an exothermic reaction using oxygen-containing compounds such as alcohol as raw materials. However, temperature control becomes difficult in reactions using ethanol, which induces an endothermic reaction, as a raw material.

Therefore, there is a need for a method that facilitates the control of reactor temperature, particularly in the olefin conversion process where temperature fluctuations are prone to occur.

Therefore, it is conceivable to include a dehydration step to dehydrate ethanol, and to use the dehydration reaction gas containing ethylene in the olefin conversion step to facilitate temperature control in the reactor during the olefin conversion step. However, we found that the dehydration step presents a challenge in temperature control due to the endothermic effect of the ethanol dehydration reaction.

Therefore, the present invention aims to provide a method for converting ethanol, a method for producing hydrocarbons, a method for producing propylene, a method for producing aromatic compounds, and an ethanol conversion apparatus, all of which facilitate the control of the reactor temperature during the dehydration process.

The present inventors, after diligent research to achieve the above objectives, discovered that when producing olefins with three or more carbon atoms from ethanol, the process involves a dehydration step of dehydrating ethanol and an olefin conversion step. Furthermore, by including a composition X containing a hydrocarbon with four or more carbon atoms as the dehydration raw material in the dehydration step, it becomes easier to control the reactor temperature.

That is, the present invention encompasses the following embodiments.
<1>
A dehydration step involves dehydrating a composition X containing a hydrocarbon having 4 or more carbon atoms and a dehydration raw material containing ethanol in a reactor using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene.
The olefin conversion step involves contacting the mixed raw materials containing the dehydrated reaction gas with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms.
A method for converting ethanol, including [the specified substance].
<2>
The reaction gas is separated into a fraction A mainly containing hydrocarbons having 1 to 3 carbon atoms and a fraction B mainly containing hydrocarbons having 4 to 6 carbon atoms,
The method for converting ethanol according to <1>, wherein at least a portion of the fraction B is supplied as the composition X into the reactor in the dehydration step.
<3>
The method for converting ethanol according to <1> or <2>, wherein the mass ratio of composition X to ethanol (composition X/ethanol) in the dehydration step is 0.10 to 4.0.
<4>
A method for converting ethanol according to any one of <1> to <3>, wherein the composition X contains 50% by mass or more of hydrocarbons having 4 to 6 carbon atoms.
<5>
A method for converting ethanol according to any one of <1> to <4>, wherein the supply temperature of the composition X into the reactor is 200°C to 530°C.
<6>
A dehydration step involves dehydrating a dehydration raw material containing ethanol and 100 parts by mass or more of water per 100 parts by mass of ethanol in a reactor using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene.
The olefin conversion step involves contacting the mixed raw materials containing the dehydrated reaction gas with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms.
A method for converting ethanol, including [the specified substance].
<7>
A method for converting ethanol according to any one of <1> to <6>, wherein the molar ratio of ethylene/(ethanol + 2 × diethyl ether) in the mixed raw materials is 0.40 to 3.0.
<8>
A method for converting ethanol according to any one of <1> to <7>, wherein the mixed raw material contains diethyl ether.
<9>
A method for converting ethanol according to any one of <1> to <8>, wherein the content of diethyl ether in the mixed raw materials is 10% by mass or less.
<10>
A method for converting ethanol according to any one of <1> to <9>, wherein the content of diethyl ether in the dehydration reaction gas is 10% by mass or less.
<11>
A method for converting ethanol according to any one of <1> to <10>, wherein the mixed raw material contains a hydrocarbon having 4 to 6 carbon atoms.
<12>
A method for converting ethanol according to any one of <1> to <11>, wherein the molar ratio of olefins having 4 to 6 carbon atoms in the mixed raw materials is 3.5 or less.
<13>
The method for converting ethanol according to any one of <1> to <12>, wherein the reactor in the dehydration step is an adiabatic reactor.
<14>
The method for converting ethanol according to any one of <1> to <13>, wherein the reactor in the olefin conversion step is an adiabatic reactor.
<15>
The method for converting ethanol according to <14>, wherein the adiabatic reactor in the olefin conversion step is a fixed-bed single-stage adiabatic reactor.
<16>
The carbon removal step 1 separates the aforementioned fraction A into a fraction C mainly containing hydrocarbons with 1 carbon atom and a fraction D mainly containing hydrocarbons with 2 to 3 carbon atoms.
The carbon removal step 2 separates the aforementioned fraction D into a fraction E mainly containing hydrocarbons with 2 carbon atoms and a fraction F mainly containing hydrocarbons with 3 carbon atoms.
The ethylene purification step separates the aforementioned fraction E into a fraction G mainly containing ethylene and a fraction H mainly containing ethane.
A propylene purification step is performed to separate the aforementioned fraction F into fraction I, which mainly contains propylene, and fraction J, which mainly contains propane.
A method for converting ethanol as described in any of <1> to <15>, including the above.
<17>
The method for converting ethanol according to any one of <1> to <16>, wherein the dehydration catalyst is a solid acid catalyst.
<18>
The method for converting ethanol according to <17>, wherein the solid acid catalyst is a zeolite-containing catalyst.
<19>
The method for converting ethanol according to <18>, wherein the silica/alumina molar ratio of the zeolite in the zeolite-containing catalyst is 20 to 2000.
<20>
The method for converting ethanol according to <18> or <19>, wherein the zeolite-containing catalyst contains at least one element selected from the group consisting of phosphorus and elements belonging to Group 11 of the periodic table.
<21>
The method for converting ethanol according to any one of <1> to <20>, wherein the olefin conversion catalyst is a solid acid catalyst.
<22>
The method for converting ethanol according to <21>, wherein the solid acid catalyst is a zeolite-containing catalyst.
<23>
The method for converting ethanol according to <22>, wherein the silica/alumina molar ratio of the zeolite in the zeolite-containing catalyst is 20 to 2000.
<24>
The method for converting ethanol according to <22> or <23>, wherein the zeolite-containing catalyst contains at least one element selected from the group consisting of phosphorus and elements belonging to Group 11 of the periodic table.
<25>
A method for converting ethanol according to any one of <1> to <24>, comprising a cooling step after the olefin conversion step, in which the reaction gas is cooled and separated into a fraction K mainly containing hydrocarbons having 1 to 6 carbon atoms and a fraction L mainly containing water, hydrocarbons having 7 or more carbon atoms and aromatic compounds.
<26>
After the olefin conversion step, a cooling step is performed to cool the reaction gas and separate it into a fraction K mainly containing hydrocarbons having 1 to 6 carbon atoms and a fraction L mainly containing water, hydrocarbons having 7 or more carbon atoms, and aromatic compounds.
A method for converting ethanol according to any one of <1> to <25>, comprising a separation step of separating the aforementioned fraction K into a fraction A mainly containing hydrocarbons having 1 to 3 carbon atoms and a fraction B mainly containing hydrocarbons having 4 to 6 carbon atoms.
<27>
The method for converting ethanol according to <26>, wherein the reactor in the olefin conversion step is an adiabatic reactor.
<28>
The method for converting ethanol according to <27>, wherein the reactor in the dehydration step is an adiabatic reactor.
<29>
A dehydration step involves dehydrating a composition X containing a hydrocarbon having 4 or more carbon atoms and a dehydration raw material containing ethanol in a reactor using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene.
The olefin conversion step involves contacting the mixed raw materials containing the dehydrated reaction gas with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms.
A method for producing hydrocarbons, including
<30>
A dehydration step involves dehydrating a dehydration raw material containing ethanol and 100 parts by mass or more of water per 100 parts by mass of ethanol in a reactor using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene.
The olefin conversion step involves contacting the mixed raw materials containing the dehydrated reaction gas with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms.
A method for producing hydrocarbons, including
<31>
A propylene separation step is performed to separate a fraction mainly containing propylene from the reaction gas obtained by the ethanol conversion method described in any of <1> to <28>.
A method for producing propylene, including the method described above.
<32>
Aromatic compound separation step, which separates a fraction mainly containing aromatic compounds from the reaction gas obtained by the ethanol conversion method described in any of <1> to <28>,
A method for producing aromatic compounds, including
<33>
A reactor that dehydrates a dehydration raw material containing ethanol using a dehydration catalyst to obtain a dehydrated reaction gas containing ethylene,
A reactor comprising: contacting a mixed raw material containing the dehydrated reaction gas with an olefin conversion catalyst to obtain a reaction gas containing an olefin having 3 or more carbon atoms;
A composition X supply line is used to introduce a composition X containing a hydrocarbon having 4 or more carbon atoms into a reactor that obtains the dehydration reaction gas.
An ethanol conversion device that includes [the specified ingredient].
<34>
The apparatus further includes a separation device for separating the reaction gas into a fraction A mainly containing hydrocarbons having 1 to 3 carbon atoms and a fraction B mainly containing hydrocarbons having 4 to 6 carbon atoms.
The ethanol conversion apparatus according to <33>, wherein at least a portion of the fraction B is supplied as the composition X to the composition X supply line.
<35>
An ethanol conversion apparatus according to <33> or <34>, comprising a cooler for cooling the reaction gas and separating it into a fraction K mainly containing hydrocarbons having 1 to 6 carbon atoms and a fraction L mainly containing water, hydrocarbons having 7 or more carbon atoms and aromatic compounds.
<36>
The ethanol conversion apparatus according to <35>, wherein the separation device separates the fraction K separated by the cooler.
<37>
The ethanol conversion apparatus according to any one of <33> to <36>, wherein the reactor for obtaining the dehydration reaction gas is an adiabatic reactor.
<38>
The ethanol conversion apparatus according to any one of <33> to <37>, wherein the reactor for obtaining the reaction gas containing the olefin having 3 or more carbon atoms is an adiabatic reactor.

According to the present invention, it is possible to provide a method for converting ethanol, a method for producing hydrocarbons, a method for producing propylene, a method for producing aromatic compounds, and an ethanol conversion apparatus, all of which facilitate the control of the reactor temperature during the dehydration process.

Figure 1 shows a schematic diagram of one embodiment of an ethanol conversion apparatus. Figure 2 shows a schematic diagram of one embodiment of a fixed-bed, single-stage adiabatic reactor. Figure 3 shows a schematic diagram of one embodiment of a single-tube fixed-bed isothermal reactor. Figure 4 shows a schematic diagram of one embodiment of an ethanol conversion apparatus. Figure 5 shows a schematic diagram of one embodiment of an ethanol conversion apparatus. Figure 6 shows a schematic diagram of one embodiment of an ethanol conversion apparatus.

The present invention will be described in detail below. However, the present invention is not limited to the following embodiments (this embodiment), and can be implemented with various modifications within the scope of its gist.
In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step can be arbitrarily combined with the upper or lower limit of a numerical range in another step.

[Method for converting ethanol]
The method for converting ethanol according to this embodiment is:
A dehydration step involves dehydrating a composition X containing a hydrocarbon with four or more carbon atoms and a dehydration raw material containing ethanol in a reactor using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene.
The olefin conversion step involves contacting the mixed raw materials containing the dehydrated reaction gas with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms.
Includes.
According to the above embodiment, it is possible to provide a method for converting ethanol, a method for producing hydrocarbons, a method for producing propylene, a method for producing aromatic compounds, and an ethanol conversion apparatus, all of which facilitate the control of the reactor temperature in the dehydration process. Specifically, by dehydrating a dehydration raw material containing ethanol in the dehydration process to produce ethylene, and then using the ethylene-containing raw material in the olefin conversion process, the olefin conversion process can be carried out by adjusting the ethylene/ethanol ratio in the mixed raw materials. This allows for adjustment of the balance between exothermic and endothermic reactions in the olefin conversion process, suppressing temperature fluctuations, facilitating control of the reactor temperature, and enabling the conversion of ethanol into the target compound with high yield. In addition, by including a composition X containing hydrocarbons with four or more carbon atoms in the dehydration raw material used in the dehydration process, temperature changes in the dehydration process are suppressed, and control of the reactor temperature is facilitated. Composition X containing hydrocarbons with four or more carbon atoms does not react, or reacts very little, under the conditions for carrying out the dehydration reaction. Therefore, composition X functions as an inert composition that does not participate in the reaction in the dehydration process. The inclusion of an inert composition in the dehydration process reduces temperature fluctuations within the reactor, even during the endothermic dehydration reaction of ethanol, thus facilitating temperature control in the dehydration process. Furthermore, hydrocarbons with four or more carbon atoms are sent to the olefin conversion process as part of the dehydration reaction gas, where they react as mixed raw materials and are converted into the target compound.

In another form, the ethanol conversion method according to this embodiment is:
A dehydration step involves dehydrating a dehydration raw material containing ethanol and 100 parts by mass or more of water per 100 parts by mass of ethanol in a reactor using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene.
The olefin conversion step involves contacting the mixed raw materials containing the dehydrated reaction gas with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms.
Includes.
According to the above embodiments, it is possible to provide a method for converting ethanol, a method for producing hydrocarbons, a method for producing propylene, a method for producing aromatic compounds, and an ethanol conversion apparatus, all of which facilitate the control of the reactor temperature in the dehydration step. Specifically, by dehydrating a dehydration raw material containing ethanol in the dehydration step to produce ethylene, and then using the ethylene-containing raw material in the olefin conversion step, the olefin conversion step can be carried out by adjusting the ethylene/ethanol ratio in the mixed raw material, thereby adjusting the balance between the exothermic and endothermic reactions in the olefin conversion step, suppressing temperature fluctuations, facilitating control of the reactor temperature, and enabling the conversion of ethanol into the target compound with high yield. In addition, by including water in the dehydration raw material used in the dehydration step, temperature changes in the dehydration step are suppressed, and control of the reactor temperature is facilitated. Water does not react, or hardly reacts, under the conditions for carrying out a dehydration reaction. Therefore, water functions as an inert component that does not participate in the reaction in the dehydration step. The inclusion of an inert component in the dehydration process reduces temperature fluctuations within the reactor, even during the endothermic dehydration reaction of ethanol, thus facilitating temperature control within the reactor during the dehydration process.

The ethanol conversion apparatus used in this embodiment will be described below, followed by a step-by-step explanation of each process.

Figure 1 is a schematic diagram of an ethanol conversion apparatus. The ethanol conversion apparatus 100 comprises a reactor 1 for obtaining a dehydration reaction gas and a reactor 2 for obtaining a reaction gas. In reactor 1, a dehydration raw material containing ethanol is dehydrated using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene. In other words, the dehydration process is performed in reactor 1. Details of this reactor will be described later. In reactor 2, a mixed raw material containing the dehydration reaction gas is brought into contact with an olefin conversion catalyst to obtain a reaction gas containing an olefin with three or more carbon atoms. In other words, the olefin conversion process is performed in reactor 2. Details of this reactor will be described later.

In the ethanol conversion apparatus 100, the ethanol supply line 11a has a dewatering raw material supply line 11b and an ethanol supply line 11c that directly introduces ethanol into the olefin conversion process, via a control valve V1. The control valve V1 adjusts the amount of ethanol introduced into reactor 1 and the amount of ethanol introduced into reactor 2 via bypass. Alternatively, the entire amount of ethanol can be supplied to the dewatering process without bypassing it.

The dehydration reaction gas obtained from reactor 1 is introduced into reactor 2 via the dehydration reaction gas supply line 11d. Meanwhile, ethanol is introduced into reactor 2 from the ethanol supply line 11c. This mixture of dehydration reaction gas and ethanol is converted within reactor 2 as a mixed raw material in the olefin conversion process. The reaction gas generated in reactor 2 is sent to a purification facility to obtain target compounds such as propylene and aromatic compounds.

<Dehydration process>
In the dehydration step according to this embodiment, a dehydration raw material containing ethanol is dehydrated in a reactor using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene. In this step, _H₂O is removed from ethanol to obtain ethylene.

(Dehydrated raw material)
The raw materials introduced into the reactor during the dehydration process are referred to as "dehydration raw materials." The dehydration raw materials contain composition X, which contains hydrocarbons with four or more carbon atoms, and ethanol. Alternatively, the dehydration raw materials contain ethanol and 100 parts by mass or more of water per 100 parts by mass of ethanol. This makes it possible to provide an ethanol conversion method, a hydrocarbon production method, a propylene production method, an aromatic compound production method, and an ethanol conversion apparatus that facilitates the control of the reactor temperature during the dehydration process. The dehydration raw materials contain a predetermined amount or more of water, which facilitates the control of the reactor temperature during the dehydration process. In addition to hydrocarbons with four or more carbon atoms, composition X may contain dilution inert gases such as nitrogen, hydrogen, or methane, and water.
Among these, the dehydrating raw material is preferably one that contains the above-mentioned composition X. By selecting composition X, it is possible to suppress catalyst degradation and the by-product formation of diethyl ether associated with catalyst degradation, because it is less reactive than water.

From the viewpoint of facilitating operational control in each process, the content of hydrocarbons having 4 or more carbon atoms in composition X is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

From the viewpoint of facilitating operational control in each process, the content of hydrocarbons having 4 to 6 carbon atoms in composition X is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

Examples of hydrocarbons with four or more carbon atoms contained in composition X include aliphatic compounds and aromatic carbon compounds such as butene, butane, pentene, pentane, hexene, hexane, heptene, heptane, and octene.

In the dehydration process, the mass ratio of composition X to ethanol (composition X/ethanol) is preferably 0.10 to 4.0, more preferably 0.15 to 2.0, and even more preferably 0.20 to 1.0, from the viewpoint of facilitating easier control of the reactor temperature during the dehydration process.

In this embodiment, when the dehydrating raw material contains water, the water content in the dehydrating raw material is preferably 100 parts by mass or more, more preferably 110 parts by mass or more, and even more preferably 120 to 300 parts by mass, relative to 100 parts by mass of ethanol in the dehydrating raw material.

In the dehydration step, it is preferable to supply composition X to the reactor, and more preferably to supply composition X to the reactor in a heated state. The supply temperature of composition X to the reactor is preferably 200°C to 530°C, more preferably 220°C to 500°C, and even more preferably 240°C to 480°C. By setting the temperature of composition X within this temperature range, the temperature inside the reactor can be controlled without applying external heat, or with minimal external heat application.

From the viewpoint of environmental friendliness, ethanol used in dehydration raw materials is preferably derived from biomass. Biomass refers to organic resources other than fossil resources originating from plants and animals, and "biomass-derived" means a compound manufactured using biomass as a raw material.

These ethanols may produce water as a by-product during their manufacturing process, or absorb moisture from the atmosphere. Therefore, in the conversion method of this embodiment, the ethanol used as the dehydration raw material may contain water.

In the dehydration raw material, the mass ratio of hydrocarbons with 4 or more carbon atoms to ethanol is preferably 0.0 to 8.0, more preferably 0.1 to 6.0, even more preferably 0.5 to 5.0, and even more preferably 0.8 to 3.0, from the viewpoint of controlling the temperature in the reactor to obtain ethylene by the dehydration reaction of ethanol.

(Reactor)
The reactor used in the dehydration process (reactor 1 in Figure 1) can be either an adiabatic reactor or an isothermal reactor. In this embodiment, since the temperature inside the reactor is easily controlled in the dehydration process, for example, whether an adiabatic reactor or an isothermal reactor is used, the temperature range inside the reactor can be made relatively smaller, although the absolute value will differ depending on which reactor is used. Among these, an isothermal reactor is preferred from the viewpoint of superior temperature control inside the reactor, and an adiabatic reactor is preferred from the viewpoint of superior operability. If necessary, a heating device for heating the raw materials can be provided in front of the reactor.

[Adiabatic reactor]
Regarding adiabatic reactors, refer to the description in Adiabatic Fixed-Bed Reactors (Elsevier, 2014, Ch.1, P.4, L.5-24 ISBN: 978-0-12-801306-9). Examples of adiabatic reactors include fixed-bed adiabatic reactors, moving-bed adiabatic reactors, and fluidized-bed adiabatic reactors, but a fixed-bed adiabatic reactor is preferred for the method of this embodiment. Among fixed-bed adiabatic reactors, a fixed-bed single-stage adiabatic reactor with only one fixed catalyst bed is more preferred. As carbonaceous material (coke) accumulates on the catalyst during the reaction, a multi-tower switching type fixed-bed single-stage adiabatic reactor that can burn off this carbonaceous material while continuing the reaction is preferred.

Figure 2 is a schematic diagram of a fixed-bed, single-stage insulated reactor. The fixed-bed, single-stage insulated reactor 10a comprises a reaction casing 12 with an insulating material 121 on its outer periphery, a catalyst bed 13, a reactor inlet 14, and a reactor outlet 15. The insulating material 121 on the outer periphery of the reaction casing 12 prevents heat from escaping from the reactor. In the manufacturing method according to this embodiment, the temperature inside the reactor can be controlled by the heat generated and absorbed by the reaction.

The catalyst bed 13 is filled with a catalyst, which will be described later. A first sheathed thermocouple 161 is placed just before contact with the catalyst bed inlet 131 of the catalyst bed 13. A second sheathed thermocouple 162 is placed immediately after passing through the catalyst bed outlet 132 of the catalyst bed 3. These thermocouples measure the temperature of the mixed raw materials just before contact with the catalyst bed inlet 131 and the reaction gas immediately after passing through the catalyst bed outlet 132. The positions of these thermocouples can be changed as needed. The catalyst bed 13 may be multi-stage, but a single-stage type is preferred, as shown in Figure 2.

In a fixed-bed, single-stage insulated reactor 10a, the mixed raw materials are introduced from the reactor inlet 14, brought into contact with the catalyst bed 13, and the reaction gas is removed from the reactor outlet 15.

[Isothermal reactor]
An isothermal reactor is a reactor that has the function of maintaining a constant temperature inside the reactor by external cooling or heating. Examples of isothermal reactors include fixed-bed isothermal reactors, moving-bed isothermal reactors, and fluidized-bed isothermal reactors, but a fixed-bed isothermal reactor is preferred for the method of this embodiment. Among fixed-bed isothermal reactors, a multi-tube fixed-bed isothermal reactor is more preferred from the viewpoint of superior controllability of the reaction temperature, as the diameter of each reactor is smaller than that of a single-tube fixed-bed isothermal reactor. As carbonaceous material (coke) accumulates on the catalyst during the reaction, a multi-column switching type fixed-bed isothermal reactor that can burn off this carbonaceous material while continuing the reaction is preferred.

Figure 3 is a schematic diagram of a single-tube fixed-bed isothermal reactor. The single-tube fixed-bed isothermal reactor 10b is basically the same in configuration as the fixed-bed single-stage insulated reactor 10a; therefore, the same reference numerals are used for similar components, and their explanation is omitted. The fixed-bed single-stage isothermal reactor 10b differs from the fixed-bed single-stage insulated reactor 1 in that it uses a reaction casing 12b with a heat transfer medium layer 121b on its outer circumference. The reaction casing 12b is heated or cooled by controlling the temperature of the heat transfer medium layer 121b on its outer circumference, thereby maintaining a constant temperature for the catalyst bed 13.

[Reaction conditions]
The reaction temperature in the dehydration step is preferably 200 to 530°C, more preferably 250 to 500°C, and even more preferably 270 to 480°C, from the viewpoint of suppressing catalyst coking degradation while allowing the ethanol dehydration reaction to proceed.

When using an adiabatic reactor, the reaction temperature is as follows: The catalyst bed inlet temperature is the temperature of the mixed raw materials immediately before the raw material fluid comes into contact with the catalyst bed packed in the adiabatic reactor. The catalyst bed outlet temperature is the temperature of the reaction gas immediately after it passes through the catalyst bed. The temperatures of the mixed raw materials and reaction gas referred to here are temperatures between 0d and 0.8d, where the center of the reactor is defined as 0 and the distance from the center of the reactor to the inner wall of the reactor is d, in a plane perpendicular to the direction of fluid flow. The average inlet and outlet reaction temperature is calculated by measuring the catalyst bed inlet temperature and catalyst bed outlet temperature, as shown in Figure 2, and using the formula: [catalyst bed inlet temperature + catalyst bed outlet temperature] / 2 (hereinafter also simply referred to as "reaction temperature"). When using an adiabatic reactor, the catalyst bed inlet temperature is preferably 350°C to 550°C, and the catalyst bed outlet temperature is preferably 100°C to 450°C. Among these, an outlet temperature of 250°C or higher is more preferable from the viewpoint of superior efficiency in the dehydration reaction.

When using an isothermal reactor, the temperature inside the reactor is considered uniform, so the catalyst bed inlet temperature is treated as the dewatering temperature. The catalyst bed inlet temperature is the temperature of the dewatering raw material just before the raw material fluid comes into contact with the catalyst bed filling the reactor. Here, the temperature of the dewatering raw material refers to the temperature between 0d and 0.8d, where 0 is the center of the reactor and d is the distance from the center of the reactor to the inner wall of the reactor, in a plane perpendicular to the fluid flow direction. In the conversion method of this embodiment, a dewatering temperature of 200°C to 450°C is preferable. Among these, a temperature of 350°C or lower is more preferable from the viewpoint of superior degradation resistance of the heat transfer medium used in the isothermal reactor.

The reaction pressure in the dehydration process is preferably 0.01 to 3.0 MPaG, and more preferably 0.01 to 1.0 MPaG.

The supply rate of the dewatering raw material is preferably 0.1 to 1000 ^hr⁻¹ , more preferably 0.1 to 500 ^hr⁻¹ , and even more preferably 0.5 to 100 ^hr⁻¹ , in terms of the mass-based space velocity (WHSV) of the dewatering catalyst. In the conversion method of this embodiment, WHSV is calculated after converting ethanol to ethylene as shown in the following formula. Furthermore, the raw material supply mass flow rate is preferably 1 kg/hr or more, more preferably 10 kg/hr or more, and even more preferably 1 t/hr or more, from the viewpoint of excellent productivity of the target compound.
WHSV (hr ^{- 1} ) = Ethylene equivalent ethanol supply flow rate (kg/hr) / Catalyst amount (kg)
Ethylene-equivalent ethanol flow rate (kg/hr) = Ethanol flow rate (kg/hr) × Ethylene molecular weight (g/mol) / Ethanol molecular weight (g/mol)

[Dehydration catalyst]
The dehydration catalyst of this embodiment is a catalyst that exhibits catalytic activity in dehydrating ethanol and converting it to ethylene. The dehydration catalyst is preferably a solid catalyst. Examples of such catalysts include zeolite-containing catalysts, heteropoly acid catalysts, and alumina catalysts. An example of an alumina catalyst is a SynDol catalyst. Among these, zeolite-containing catalysts are preferred from the viewpoint of excellent thermal durability of the catalyst.

(Zeolite-containing catalyst)
A zeolite-containing catalyst is a catalyst powder or molded body containing zeolite as an active species. In the conversion method of this embodiment, it is preferable to use a so-called intermediate-pore zeolite, which has a pore diameter of 5 to 6 Å, as the zeolite in the zeolite-containing catalyst. An intermediate-pore zeolite means "a zeolite whose pore diameter range is intermediate between the pore diameter of small-pore zeolites, such as type A zeolites, and the pore diameter of large-pore zeolites, such as mordenite, type X, and type Y zeolites." An intermediate-pore zeolite has a so-called 10-membered oxygen ring in its crystal structure.

Examples of zeolites with intermediate pore sizes include ZSM-5, ZSM-8, ZSM-11, ZSM-12, ZSM-21, ZSM-23, ZSM-35, and ZSM-38. Among these, ZSM-5 type zeolites such as ZSM-5, ZSM-11, and ZSM-8, and ZSM-38 are preferred. Furthermore, zeolites similar to ZSM-5 and ZSM-11 described in Stud. Surf. Sci. Catal. 1987, 33, 167-215 can be used. Among these, MFI type zeolites are preferred from the viewpoint of superior catalytic performance (catalytic activity and durability against coking), and ZSM-5 is more preferred.

The silica/alumina ( _SiO₂ / _Al₂O₃ ) molar ratio of the zeolite contained in _the zeolite-containing catalyst of this embodiment can be appropriately selected, but from the viewpoint of excellent catalytic activity and propylene selectivity, it is preferably 20 to 2000, more preferably 40 to 1800, and even more preferably 150 to 1500. The silica/alumina molar ratio of the zeolite can be measured by known methods, for example, by completely dissolving the zeolite in an alkaline aqueous solution and analyzing the resulting solution by plasma emission spectroscopy or the like.

There are no particular restrictions on the method of synthesizing the zeolite in this embodiment; however, it can be produced by optimizing various conditions of conventionally known hydrothermal synthesis methods for MFI-type zeolites. Generally, efficient means of obtaining MFI-type zeolites by hydrothermal synthesis include methods using appropriate organic additives (SDAs), such as ammonium salts, urea compounds, amines, and alcohols, or methods adding hydrothermally synthesized MFI zeolite as a seed crystal or as a seed slurry in the crystalline stage. Furthermore, it is known that not only organic SDAs but also inorganic cations and anions are involved in the structure, and zeolite synthesis depends on the combined function of each component. In the hydrothermal synthesis method of MFI-type zeolites described above, a suitable catalyst can be obtained by appropriately optimizing the raw material composition, such as the type and amount of raw materials and additives (SDAs), pH, silica/alumina molar ratio, medium, and the relative abundance of cations and anions, as well as synthesis conditions such as synthesis temperature and synthesis time.

Specifically, examples include the synthesis method using the seed slurry described in Japanese Patent Publication No. 5426983, and the method exemplified in *The Hydrothermal Synthesis of Zeolites* (Chemical Reviews, 2003, 103, 663-702).

Furthermore, commercially available zeolites can also be used, provided they possess the specific physical properties and composition described above.

In this embodiment, the zeolite-containing catalyst preferably contains phosphorus and at least one element selected from the group consisting of elements belonging to Group 11 of the periodic table (hereinafter, these elements are collectively referred to as doped elements). Among these, the zeolite-containing catalyst used as a dehydration catalyst preferably contains phosphorus.

Examples of phosphorus forms include phosphorus polymers (e.g., polyphosphate), phosphorus oxides (e.g., _P2O5 ), and compounds in which phosphorus is added to _the aluminum in the zeolite. Multiple forms of these may also be included. When the zeolite contains aluminum, phosphorus has the effect of suppressing the dealuminization of the zeolite. In the method according to this embodiment, water is generated in the reactor, and the raw material, ethanol, may also contain water, making it easy for the reactor to become a high-temperature steam atmosphere that causes dealuminization. Dealuminization leads to structural breakdown and degradation of the zeolite-containing catalyst's activity, but the inclusion of phosphorus in the zeolite-containing catalyst suppresses the dealuminization of the zeolite, thereby increasing the catalyst's durability.

Elements belonging to Group 11 of the periodic table include copper, silver, and gold. Including elements from Group 11 suppresses the dealuminization of the zeolite, thereby increasing the durability of the catalyst. Among these elements from Group 11, silver is preferred from the viewpoint of superior loading efficiency.

The doping element content in the zeolite-containing catalyst is preferably 0.01 to 2.0% by mass relative to the total mass of the catalyst, and more preferably 0.05 to 2.0% by mass from the viewpoint of excellent effect in suppressing dealuminization.

In this embodiment, the doped element content in the zeolite-containing catalyst is shown as a value measured using an X-ray fluorescence analyzer. The phosphorus, copper, silver, or gold content can be measured using a commercially available X-ray fluorescence analyzer under normal conditions according to the instruction manual. For example, when using a Rigaku product, product name "RIX3000," the measurement conditions can be set to use P-Kα rays, tube voltage of 50 kV, and tube current of 50 mA.

In this embodiment, phosphoric acid and/or phosphates (hereinafter also referred to as "phosphorus raw material") are used as the phosphorus raw material for the zeolite-containing catalyst. Phosphates are more preferred as the phosphorus raw material, and among phosphates, compounds exhibiting a solubility of 1 g or more per 100 g of water at 25°C are even more preferred.

Examples of phosphoric acid include phosphoric acid and pyrophosphate. Examples of phosphate salts include ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium ammonium hydrogen phosphate, potassium hydrogen phosphate, aluminum hydrogen phosphate, sodium phosphate, potassium phosphate, etc. Among these, ammonium phosphate salts, which have relatively high solubility in water, are preferred, and more preferably, at least one selected from the group consisting of ammonium phosphate, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate. These may be used individually or in combination of two or more.

In this embodiment, metal nitrate salts such as copper nitrate and silver nitrate may be used as raw materials for the elements belonging to Group 11 of the periodic table contained in the zeolite-containing catalyst. A zeolite-containing catalyst containing elements belonging to Group 11 of the periodic table can be obtained by ion exchange with a metal nitrate salt using a zeolite-containing catalyst containing sodium as a countercation, followed by sintering.

The zeolite-containing catalyst of this embodiment can be manufactured by molding, for example, the following method using a zeolite having the specific physical properties and composition described above. The molding method is not particularly limited, and general methods can be used. Specifically, methods include compression molding of the catalyst component, extrusion molding, and spray-dry molding, which is optimal for fluidized bed reaction systems.
Furthermore, a binder can be used for molding. The binder is not particularly limited, and for example, silica, alumina, and kaolin can be used individually or in combination. Commercially available binders can be used. The mass ratio of zeolite to binder is preferably in the range of 10/90 to 90/10, and more preferably in the range of 20/80 to 80/20. Among these, silica binder is preferred from the viewpoint of excellent caulking resistance.

In the ethanol conversion method of this embodiment, a pretreatment step may be performed on the zeolite-containing catalyst prior to contacting it with the raw material. A preferred pretreatment step is a heat treatment at a temperature of 300°C or higher in the presence of water vapor. Pretreatment tends to more significantly suppress catalyst degradation and improve selectivity. In the above method, it is preferable to perform the treatment at a temperature of 300°C to 900°C, with the atmosphere not particularly limited, but by circulating a mixed gas of air or an inert gas such as nitrogen and steam (water vapor), under conditions of a water vapor partial pressure of 0.01 atmospheres or higher. A more preferable heat treatment temperature is 400°C to 700°C. Furthermore, this pretreatment step can be performed using a reactor that converts ethanol and ethylene.

The amount of the dehydration catalyst is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, even more preferably 20 to 100 parts by mass, and even more preferably 25 to 80 parts by mass, per 100 parts by mass of ethanol supplied per hour, from the viewpoint of suppressing the amount of diethyl ether produced in the dehydration process.

The above dehydration process yields a dehydrated reaction gas containing ethylene.
The ethylene content in the dehydration reaction gas is preferably 20 to 80% by mass, more preferably 25 to 70% by mass, and even more preferably 25 to 60% by mass.

The water content in the dehydration reaction gas is preferably 20 to 80% by mass, more preferably 25 to 70% by mass, and even more preferably 25 to 60% by mass.

In the dehydration reaction of ethanol, diethyl ether is produced as a by-product in addition to ethylene, the target compound. The dehydration reaction gas may contain diethyl ether, but it is preferable that it does not contain diethyl ether from the viewpoint of facilitating temperature control in the reactor.
The content of diethyl ether in the dehydration reaction gas is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

The dehydration reaction gas may contain hydrocarbons having four or more carbon atoms. Including hydrocarbons with four or more carbon atoms makes it easier to control the reaction temperature in the dehydration process.
The content of hydrocarbons having 4 or more carbon atoms in the dehydration reaction gas is preferably 10 to 60% by mass, more preferably 20 to 55% by mass, and even more preferably 30 to 50% by mass.

The conversion rate of ethanol in the dehydration process is preferably 80 mol% or more, more preferably 85 mol% or more, and even more preferably 90 mol% or more.

<Olefin conversion process>
In the olefin conversion step according to this embodiment, a mixed raw material containing a dehydrated reaction gas is brought into contact with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin with 3 or more carbon atoms. By dehydrating ethanol in the dehydration step and using it in the olefin conversion step, the component ratio in the mixed raw material can be adjusted, making it easier to control the temperature inside the reactor.

Furthermore, the molar ratio of ethylene/(ethanol + 2 × diethyl ether) in the mixed raw materials used in the olefin conversion process (hereinafter also simply referred to as the "mixed raw material composition ratio") is 0.20 to 4.0. This range of mixed raw material composition ratio ensures a good balance between endothermic and exothermic reactions in the reactor, facilitating temperature control. Ethanol and diethyl ether undergo endothermic reactions during the conversion to olefins with three or more carbon atoms in the olefin conversion process. Diethyl ether, in particular, undergoes an endothermic reaction involving two atoms in this olefin conversion process, hence the multiplication by "2" in the above formula. On the other hand, ethylene undergoes exothermic reactions during the conversion to olefins with three or more carbon atoms in the olefin conversion process. Thus, it is assumed that thermal neutralization was achieved by combining endothermic and exothermic reactions that do not inhibit each other. In other words, in this embodiment, it was found that the conversion reaction from ethylene to propylene and the conversion reaction from ethanol to propylene proceed without inhibiting each other, and it is believed that the reaction temperature could be controlled by combining these exothermic and endothermic reactions. However, the factors are not limited to this.

The molar ratio of ethylene to (ethanol + 2 × diethyl ether) is 0.20 to 4.0, preferably 0.30 to 3.5, and more preferably 0.5 to 3.0, from the viewpoint of facilitating temperature control within the reactor.

[Mixed raw materials]
In the olefin conversion step of this embodiment, a mixed raw material containing a dehydration reaction gas is used. In addition to the dehydration reaction gas, ethanol may also be mixed into the mixed raw material. From the viewpoint of excellent environmental compatibility, the ethanol is preferably derived from biomass. Biomass refers to organic resources other than fossil resources that originate from plants and animals, and biomass-derived means a compound produced using biomass as a raw material.

The ethylene included in the mixed raw materials is preferably the ethylene contained in the dehydration reaction gas. Since water is produced as a by-product during the conversion of ethanol to ethylene, the dehydration reaction gas generally contains water.

From the viewpoint of excellent variability of the raw material ratio, the mixed raw materials may further contain "additional ethylene" in addition to the ethylene contained in the dehydration reaction gas. Various methods can be used to produce the "additional ethylene." For example, ethylene obtained by thermal decomposition of naphtha and/or ethane, direct or oxidative dehydrogenation of ethane, or dehydration of ethanol can be used.

The mixed raw materials may further contain hydrocarbons having 4 to 6 carbon atoms. Examples of hydrocarbons having 4 to 6 carbon atoms include olefins and saturated hydrocarbons having 4 to 6 carbon atoms. Among these, olefins having 4 to 6 carbon atoms, like ethylene and ethanol, can yield target compounds such as propylene when contacted with a conversion catalyst. Examples of hydrocarbons having 4 to 6 carbon atoms include butene, pentene, hexene, butane, pentane, and hexane. In the mixed raw materials, the molar ratio of olefins having 4 to 6 carbon atoms to ethylene is preferably 3.0 or less, more preferably 1.0 or less, and even more preferably 0.14 to 1.0. The term "olefin" above includes cycloparaffins in addition to linear, branched, and cyclic olefins.

The mixed raw materials may include, in addition to the ethylene, ethanol, and C4-C6 hydrocarbons mentioned above, hydrocarbons with 7 or more carbon atoms, methanol, propanol, dimethyl ether, diethyl ether, and other oxygen-containing compounds besides ethanol. Hydrocarbons with 7 or more carbon atoms and oxygen-containing compounds can yield the target compound by contacting them with a conversion catalyst, similar to ethylene and ethanol.

The mixed raw materials may include organic components as defined above, which can be converted to propylene by the olefin conversion process, as well as dilution inert gases such as nitrogen, hydrogen, and methane. However, hydrogen dilution is preferable. While hydrogen is sometimes used to suppress catalyst coking degradation, it simultaneously causes hydrogenation reactions of the generated propylene, negatively impacting the propylene purity (propylene/(propylene + propane)) [mol/mol]. In the method of this embodiment, even without hydrogen dilution, the catalyst coking degradation rate is low, and stable operation is possible; therefore, it is preferable not to perform hydrogen dilution.

The total content of ethylene and ethanol in the mixed raw materials is preferably 30 to 100% by mass, more preferably 40 to 100% by mass, and even more preferably 50 to 100% by mass, relative to the total amount of conversion raw materials. However, the ethanol is used in the calculation based on its equivalent mass as ethylene.

The total content of olefins with 4 to 6 carbon atoms in the mixed raw materials is preferably 65% by mass or less, and more preferably 10 to 55% by mass, relative to the total amount of conversion raw materials.

The mixed raw materials may contain diethyl ether, but it is preferable that they do not contain diethyl ether.
The content of diethyl ether in the mixed raw materials is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

The mixed raw materials may contain olefins having 4 to 6 carbon atoms, from the viewpoint of making it easier to control the temperature inside the reactor.
The molar ratio of olefins with 4 to 6 carbon atoms to ethylene in the mixed raw materials is preferably 3.5 or less, more preferably 3.0 or less, even more preferably 1.0 or less, and even more preferably 0.14 to 1.0. The term "olefin" above includes linear, branched, and cyclic olefins, as well as cycloparaffins.

In the conversion method of this embodiment, water vapor can be included in the mixed raw materials. Since the ethylene and ethanol contained in the mixed raw materials are produced by various manufacturing methods, they contain "water vapor generated during the manufacturing process." Here, "water vapor generated during the manufacturing process" refers to moisture generated during the manufacturing process of ethylene and/or ethanol that has not been removed.

In the propylene production method of this embodiment, water vapor can be included in the mixed raw materials in addition to the "water vapor generated during the manufacturing process." Water vapor has the effect of suppressing coking degradation by lowering the partial pressure of olefins and improving the yield of lower olefins. On the other hand, since water vapor may promote the dealuminization of zeolites, it is preferable not to include water vapor in the mixed raw materials in addition to the "water vapor generated during the manufacturing process."

[Reactor]
The reactor used in the olefin conversion process (reactor 2 shown in Figure 1) can be either an adiabatic reactor or an isothermal reactor. Of these, an isothermal reactor is preferred from the viewpoint of superior temperature control within the reactor, while an adiabatic reactor is preferred from the viewpoint of superior operability. The adiabatic reactor and the isothermal reactor are as described above.

[Reaction conditions]
The reaction temperature in the olefin conversion step is preferably 300 to 600°C, more preferably 400 to 590°C, and even more preferably 450 to 550°C, from the viewpoint of obtaining olefins with 3 or more carbon atoms in good yield. From the viewpoint of excellent propylene yield, a reaction temperature of 400°C or higher is preferable. On the other hand, from the viewpoint of suppressing accelerated coking degradation which is promoted at high temperatures, a temperature of 600°C or lower is preferable.
Furthermore, the definition of reaction temperature in an adiabatic reactor is synonymous with that of the dehydration process.

The temperature difference between the outlet temperature of the catalyst bed and the inlet temperature of the catalyst bed is preferably -80K to 80K, and more preferably -60K to 60K.
The reaction pressure is preferably 0.01 to 3.0 MPaG, and more preferably 0.01 to 1.0 MPaG.

The supply rate of the mixed raw materials is preferably 0.1 to 1000 ^hr⁻¹ , more preferably 0.1 to 500 ^hr⁻¹ , and even more preferably 0.5 to 100 ^hr⁻¹ , based on the mass-based space velocity (WHSV) of the olefin conversion catalyst. In the olefin conversion step, the WHSV is calculated by converting ethanol to ethylene as shown in the formula below. Furthermore, the raw material supply mass flow rate is preferably 1 kg/hr or more, more preferably 10 kg/hr or more, and even more preferably 1 t/hr or more, from the viewpoint of excellent productivity of the target compound.
WHSV (hr ^{- 1} ) = Olefin supply flow rate (kg/hr) / Catalyst amount (kg)
Olefin supply flow rate (kg/hr) = Ethylene flow rate (kg/hr) + Ethylene-equivalent ethanol flow rate (kg/hr) + C4-C6 olefin flow rate (kg/hr)
Ethylene-equivalent ethanol flow rate (kg/hr) = Ethanol flow rate (kg/hr) × Ethylene molecular weight (g/mol) / Ethanol molecular weight (g/mol)

[Olefin conversion catalyst]
An olefin conversion catalyst is a catalyst that exhibits catalytic activity in converting olefins and ethanol into target compounds such as propylene. The olefin conversion catalyst is preferably a solid catalyst. As such a catalyst, a zeolite-containing catalyst is preferred from the viewpoint of excellent thermal durability of the catalyst. The zeolite-containing catalyst is as described above in the section on dehydration catalysts. A common problem in conventional olefin production using zeolites is coking degradation, in which heavy carbonaceous material (coke) accumulates inside the zeolite pores due to reaction with hydrocarbons, leading to deactivation. In order to regenerate the catalyst performance, it is necessary to burn off the coke in an atmosphere containing oxygen molecules, but this coke combustion leads to structural breakdown of the zeolite, inducing permanent degradation of the catalyst that cannot be regenerated. According to the conversion method of this embodiment, the generation of coke can be suppressed, making it easier to maintain activity even when using a zeolite-containing catalyst.

In the olefin conversion process, the zeolite-containing catalyst preferably has a silica/alumina molar ratio of 20 to 2000, more preferably 40 to 1800, and even more preferably 150 to 1500, from the viewpoint of excellent catalytic activity and propylene selectivity.

In the olefin conversion process, the zeolite-containing catalyst preferably contains at least one element selected from the group consisting of phosphorus and elements belonging to Group 11 of the periodic table. Among these, the zeolite-containing catalyst used as a dehydration catalyst preferably contains phosphorus or silver.

<Regeneration process>
The ethanol conversion method of this embodiment may include a regeneration step (hereinafter also referred to as the "regeneration step") in which coke adhering to the catalyst is burned off. When a catalyst is used in a reaction for a long period of time, coke may adhere to the catalyst, causing coking deterioration. If the catalyst has deteriorated due to coking, the deteriorated catalyst can be regenerated by burning off the coke on the catalyst at a temperature of 400 to 700°C, for example, in air or in a mixed gas of air and/or oxygen and an inert gas, preferably under conditions of an oxygen concentration of 0.1 to 2.0 volume%. Either an external regeneration method, in which the catalyst is removed from the reactor and regenerated outside the reactor, or internal regeneration, in which the catalyst is regenerated inside the reactor without being removed from the reactor, may be adopted. Furthermore, by employing a switchable reactor, reaction-regeneration switching operation can also be performed.

(Reaction-Regeneration switching operation)
Reaction-regeneration switching operation is an operating method that uses a two-column or multi-column switching reactor to simultaneously carry out the reaction process and the regeneration process. For example, in the case of a three-column switching reactor, two columns are used for the reaction process, while the remaining column is used for catalyst regeneration. Subsequently, the reaction process in one of the columns that was used for the reaction process is stopped to perform catalyst regeneration, and the reaction process is then carried out in the column that was used for catalyst regeneration. This allows for catalyst regeneration while maintaining the production capacity of two columns. This type of reaction is also called the merry-go-round method, and it is preferable from the standpoint of superior production efficiency because it does not require stopping the manufacturing process for catalyst regeneration.

[Product: Reaction gas containing olefins with 3 or more carbon atoms]
In the conversion method of this embodiment, a reaction gas containing an olefin having 3 or more carbon atoms is obtained by contacting the mixed raw materials with a conversion catalyst. The reaction gas may also contain ethylene. The reaction gas may also contain hydrogen, aliphatic hydrocarbons having 1 to 3 carbon atoms, aliphatic hydrocarbons having 4 to 6 carbon atoms, aromatic compounds, and hydrocarbons having 9 or more carbon atoms.
In this specification, aliphatic hydrocarbons having 1 to 3 carbon atoms, aliphatic hydrocarbons having 4 to 6 carbon atoms, aromatic compounds, and hydrocarbons having 9 or more carbon atoms are referred to as target compounds.

<Separation process>
In the conversion method according to this embodiment, the purification of the target compound can be efficiently carried out by providing a separation step. In the separation step, the reaction gas obtained in the reaction step described above is separated by a separation device into fraction A mainly containing hydrocarbons having 2 to 3 carbon atoms and fraction B mainly containing hydrocarbons having 4 to 6 carbon atoms. By separating into each fraction in this way, the target compound can be separated efficiently. The separation device used in the separation step is, for example, a distillation column. Alternatively, without providing a separation step, the reaction gas obtained in the reaction step described above may be introduced into the purification system of an ethylene plant, and the target compound such as ethylene, propylene, or aromatic compounds may be separated from the reaction gas in the purification system.

It is preferable to supply at least a portion of the fraction B obtained in the separation step as composition X into the reactor in the dehydration step. Reusing at least a portion of fraction B as composition X facilitates temperature control of the reactor in the dehydration step, and since fraction B is subjected to the olefin conversion step again, the target compound can be obtained efficiently.

The proportion of composition X in fraction B supplied to the reactor during the dehydration process (mass of fraction B used as composition X / total mass of fraction B) (hereinafter also referred to as the "reuse rate") is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and even more preferably 70% to 100% by mass, from the viewpoint of excellent yield of the target compound.

The method according to this embodiment may be carried out using an apparatus having a reactor 1, a reactor 2, and a first distillation column 3, as shown in Figure 4. The reaction gas obtained from the olefin conversion step performed in reactor 2 is separated in the first distillation column 3 into fraction A, mainly containing hydrocarbons with 1 to 3 carbon atoms, and fraction B, mainly containing hydrocarbons with 4 to 6 carbon atoms. Ethylene and propylene are efficiently separated from the reaction gas by separating ethylene from fraction A in a distillation column (not shown), and further separating propylene in another distillation column (not shown). Alternatively, although not shown, at least a portion of the reaction gas and/or fraction A may be introduced into the purification system of an ethylene plant, where target compounds such as ethylene and propylene may be separated from the reaction gas. Furthermore, as shown in Figure 4, at least a portion of fraction B of composition X may be supplied into reactor 1 via the supply line 12.

The method according to this embodiment can be carried out using an apparatus having a reactor 1, a reactor 2, a first distillation column 3, a second distillation column 4, a third distillation column 5, a fourth distillation column 6, and a fifth distillation column 7, as shown in Figure 5. The reaction gas obtained by the olefin conversion step carried out in reactor 2 is separated in the first distillation column 3 into fraction A mainly containing hydrocarbons having 1 to 3 carbon atoms and fraction B mainly containing hydrocarbons having 4 to 6 carbon atoms. Fraction A is separated in the second distillation column 4 into fraction C mainly containing hydrocarbons having 1 carbon atom and fraction D mainly containing hydrocarbons having 2 to 3 carbon atoms. Fraction D is separated in the third distillation column 5 into fraction E mainly containing hydrocarbons having 2 carbon atoms and fraction F mainly containing hydrocarbons having 3 carbon atoms. Fraction E is separated in the fourth distillation column 6 into fraction G mainly containing ethylene and fraction H mainly containing ethane. Fraction F is separated into fraction I, which mainly contains propylene, and fraction J, which mainly contains propane. By continuously separating the reaction gas into these fractions, the target compound, such as propylene, can be efficiently obtained. Furthermore, as shown in Figure 5, composition X may be supplied to reactor 1 via supply line 12, with at least a portion of fraction B being supplied. Alternatively, the target compound can be obtained by separating fraction A into a fraction mainly containing hydrocarbons with 1-2 carbon atoms and a fraction mainly containing hydrocarbons with 3 carbon atoms, using a similar method.

The method according to this embodiment can be carried out using an apparatus having a reactor 1, a reactor 2, a cooling tower 8, an oil-water separator 9, and a first distillation column 3, as shown in Figure 6. The reaction gas obtained by the olefin conversion step carried out in reactor 2 is separated in the cooling tower 8 into fraction K mainly containing hydrocarbons with 1 to 6 carbon atoms, and fraction L mainly containing water, hydrocarbons with 7 or more carbon atoms, and aromatic compounds. Fraction K is separated in the first distillation column 3 into fraction A mainly containing hydrocarbons with 1 to 3 carbon atoms, and fraction B mainly containing hydrocarbons with 4 to 6 carbon atoms. Fraction L is separated in the oil-water separator 9 into fraction M mainly containing hydrocarbons with 7 or more carbon atoms and aromatic compounds, and fraction N mainly containing water. By introducing fraction M into the purification system, the purification of aromatic compounds can be carried out efficiently. In this way, by separating the reaction gas into fractions A, B, and M, the purification of target compounds such as propylene and aromatic compounds can be carried out efficiently. At least a portion of fractions A, B, and M may be introduced into the purification system of an ethylene plant, where target compounds such as ethylene, propylene, and aromatic compounds may be separated from the reaction gas. Alternatively, as shown in Figure 6, at least a portion of fraction B of composition X may be supplied into reactor 1 via the supply line 12. By providing a cooling step, the amount of hydrocarbons with 7 or more carbon atoms in fraction B can be reduced, and the mass ratio of hydrocarbons with 4 to 6 carbon atoms in composition X can be improved.

In each fraction, "primarily contains" means that the total mass of the components listed as "primarily contains" exceeds 50% by mass of each fraction. These separation processes can be carried out by combining various known methods such as distillation and extraction.

As described above, various hydrocarbons can be obtained by the ethanol conversion method of this embodiment. In other words, the ethanol conversion method of this embodiment is, from another perspective, a method for producing hydrocarbons. The hydrocarbons may be either saturated or unsaturated hydrocarbons. Examples of unsaturated hydrocarbons include olefins and aromatic hydrocarbon compounds.

[Method for producing propylene, and method for producing aromatic compounds]
Various chemical products can be obtained by separating the target compound from the reaction gas obtained by this embodiment.
The propylene production method of this embodiment includes a propylene separation step in which a fraction mainly containing propylene is separated from the reaction gas obtained by the ethanol conversion method of this embodiment. Known propylene purification methods such as distillation can be used for the propylene separation step. The propylene separation step can be carried out using equipment attached to an ethylene plant by connecting part or all of the reaction gas to the purification system of an ethylene plant.
The method for producing aromatic compounds according to this embodiment includes an aromatic compound separation step in which a fraction mainly containing aromatic compounds is separated from the reaction gas obtained by the ethanol conversion method according to this embodiment. Known aromatic compound purification methods such as distillation can be used for the aromatic compound separation step. The propylene separation step can be carried out using equipment attached to an ethylene plant by connecting part or all of the reaction gas to the purification system of an ethylene plant.

The embodiment will be described in more detail below with reference to examples, but this embodiment is not limited to the following examples.

[Methods for measuring various physical properties]
The various physical properties were measured as shown below.

(1) Molar ratio of silica/alumina in zeolite-containing catalyst A solution was prepared by completely dissolving zeolite in a sodium hydroxide solution. The amounts of Si and Al contained in the solution were measured by a conventional method using an ICP (inductively coupled plasma) emission spectrometer (Rigaku, product name "JY138"), and the molar ratio of silica/alumina was derived from the results. The measurement conditions were set as follows: high-frequency power: 1 kW, plasma gas: 13 L/min, sheath gas: 0.15 L/min, nebulizer gas: 0.25 L/min, Si measurement wavelength: 251.60 nm, Al measurement wavelength: 396.152 nm.

(2) Doping element content of zeolite-containing catalyst The doping element content in the zeolite-containing catalyst was measured by a conventional method using an X-ray fluorescence analyzer (manufactured by Rigaku, product name "RIX3000").

(3) Zeolite Structural Type The structural type of the zeolite in the zeolite-containing catalyst was identified by measuring the X-ray diffraction pattern of the zeolite using an X-ray analyzer (Rigaku Co., Ltd., product name "RINT") and referring to the diffraction patterns of known zeolites. The measurement conditions were as follows.
Cu cathode, tube voltage: 40kV
Bulb current: 30mA
Scan speed: 1 deg/min

[Method for converting ethanol]
(Reactor)
The following examples and comparative examples were evaluated using either the fixed-bed single-stage adiabatic reactor 1 shown in Figure 2, or the single-tube fixed-bed isothermal reactor shown in Figure 3.

(Temperature measurement)
The temperatures at the catalyst bed inlet and outlet were measured using thermocouples inserted from outside the reactor. Specifically, as shown in Figures 2 and 3, in a plane perpendicular to the fluid flow direction, with the reactor center set to 0 and the distance from the reactor center to the reactor inner wall surface being d, temperatures were measured between 0.5d and 0.6d. The effect of heat dissipation due to the insertion of these thermocouples is negligibly small. In addition, the thermocouples were moved in the direction of fluid flow as needed to measure the lowest temperature inside the reactor.

(Dehydrated raw material)
In the examples and comparative examples, ethanol was mixed with a hydrocarbon having four or more carbon atoms, if necessary, to prepare a dehydrated raw material.

(Evaluation of the reaction in the dehydration process)
The reaction was carried out according to the following examples and comparative examples. A portion of the reactor outlet gas was sampled every 3 hours from the start of the reaction and introduced into a gas chromatograph (TCD and FID detector) to analyze the reaction gas composition. The reaction was stopped 48 hours after the start of the reaction. The average value of the GC analysis results from the start of the reaction to the stop of the reaction was calculated. When an adiabatic reactor was used, both the catalyst bed inlet temperature and the catalyst bed outlet temperature were recorded, and when an isothermal reactor was used, the catalyst bed inlet temperature was recorded as the reaction temperature.

(Mixed raw materials)
In the following embodiments, a mixed raw material was obtained by mixing the dehydration reaction gas with, if necessary, a bypass raw material and a hydrocarbon having four or more carbon atoms.
The molar ratio of ethylene/(ethanol + 2 × diethyl ether) and the molar ratio of olefins with 4 to 6 carbon atoms/ethylene in the mixed raw material gas were calculated using the following formulas.
The molar ratio of ethylene to (ethanol + 2 × diethyl ether) (-) = molar flow rate of ethylene (mol/hr) / (molar flow rate of ethanol (mol/hr) + molar flow rate of 2 × diethyl ether (mol/hr))
The molar ratio of olefins with 4 to 6 carbon atoms to ethylene (-) = flow rate of olefins with 4 to 6 carbon atoms (mol/hr) / molar flow rate of ethylene (mol/hr)

(Evaluation of the reaction in the olefin conversion process)
The reaction was carried out according to the following examples and comparative examples, so that the average inlet and outlet reaction temperature was 540°C. A portion of the reactor outlet gas was sampled every 3 hours from the start of the reaction and introduced into a gas chromatograph (TCD, FID detector) to analyze the reaction gas composition. The reaction was stopped 48 hours after the start of the reaction. The average value of the GC analysis results from the start of the reaction to the stoppage was calculated. The average inlet and outlet reaction temperature was calculated according to the formula below and is referred to as "reaction temperature" in the table.
Average inlet/outlet reaction temperature (°C) = [Catalyst bed inlet temperature (°C) + Catalyst bed outlet temperature (°C)] / 2

(Coke yield)
In the following examples and comparative examples, after the reaction was stopped, nitrogen was supplied to the reactor to purge hydrocarbons, and the catalyst bed was maintained at 500°C. Next, air/nitrogen with an oxygen concentration of 2% by volume was circulated to burn off the coke on the catalyst. During this process, the reactor outlet gas was periodically sampled, and the regenerated gas was analyzed using a gas chromatograph to measure the concentrations of _CO2 and CO. From these values, the amount of carbon attached to the catalyst was determined and defined as the coke amount. The method for regenerated gas analysis using a gas chromatograph is described below (Analysis conditions for gas chromatography). The coke yield in the following examples and comparative examples was determined according to the following formula.
Coke yield (wt ppm) = Coke amount / [Olefin supply flow rate (kg/hr) × Reaction time (hr)]
Olefin supply flow rate (kg/hr) = Ethylene flow rate (kg/hr) + Ethylene-equivalent ethanol flow rate (kg/hr) + C4-C6 olefin flow rate (kg/hr)
Ethylene-equivalent ethanol flow rate (kg/hr) = Ethanol flow rate (kg/hr) × Ethylene molecular weight (g/mol) / Ethanol molecular weight (g/mol)

[Analytical conditions for gas chromatography]
(Regeneration gas analysis)
Equipment: Shimadzu GC-8A
Columns: The following columns (1) and (2) were used, concatenated in parallel.
Column (1) A stainless steel column (3 mm inner diameter, 3 m length) packed with 80-100 mesh molecular sieves 5A (manufactured by Fujifilm Wako Pure Chemical Industries).
Column (2): A direct connection between a Porapac-Q column (3 mm inner diameter, 2 m length) manufactured by Waters Associates, USA, with a mesh size of 80-100, and a stainless steel resistance column (3 mm inner diameter, 1 m length). Column temperature: 70°C
Carrier gas (helium) flow rate: 60 mL/min

(Reaction gas analysis)
Equipment: Shimadzu GC-2030
Column: Custom capillary column SPB-1 manufactured by SUPELCO, USA (inner diameter 0.25 mm, length 60 m, film thickness 3.0 μm)
Sample gas volume: 1 mL (Sampling line should be kept warm at 200°C to 300°C)
Temperature increase program: The temperature was maintained at 40°C for 12 minutes, then increased at a rate of 5°C/minute to 200°C, and then maintained at 200°C for 22 minutes.
Split ratio: 200:1
Carrier gas (nitrogen) flow rate: 120 mL/min; FID detector: air supply pressure 50 kPa (approx. 500 mL/min), hydrogen supply pressure 60 kPa (approx. 50 mL/min)
Measurement method: A TCD detector and an FID detector were connected in series. Composition analysis was performed based on the data detected by the TCD detector for hydrogen and the data detected by the FID detector for oxygen-containing substances such as hydrocarbons and ethanol. The concentration of each component in the reaction gas was determined using a calibration curve method, and the mass produced per unit time by the reaction was calculated.

(Ethanol conversion rate and diethyl ether by-product rate)
The ethanol conversion rate represents the amount of ethanol converted during the dehydration process, and the diethyl ether by-product rate represents the conversion rate from ethanol to diethyl ether. Both were calculated using the following formulas.
Ethanol conversion rate (mol%) = (1 - Amount of ethanol contained in the dehydration reaction gas (kg/hr) / Ethanol supply flow rate to the dehydration process (kg/hr)) × 100
Diethyl ether by-production rate (mol%) = (2 × amount of diethyl ether by-production (kmol/hr) / ethanol supply flow rate to the dehydration process (kmol/hr)) × 100

(Propylene yield)
The propylene yield represents the selectivity to propylene in the olefin conversion process and was calculated using the following formula.
Propylene yield (mass%) = Mass of propylene per hour produced in the olefin conversion process (kg/hr) / Olefin supply flow rate (kg/hr)
Olefin supply flow rate (kg/hr) = Ethylene flow rate (kg/hr) + Ethylene-equivalent ethanol flow rate (kg/hr) + C4-C6 olefin flow rate (kg/hr)
Ethylene-equivalent ethanol flow rate (kg/hr) = Ethanol flow rate (kg/hr) × Ethylene molecular weight (g/mol) / Ethanol molecular weight (g/mol)

(Aromatic yield)
The aromatic yield represents the selectivity for aromatic compounds in the olefin conversion process and was calculated using the following formula.
Aromatic yield (mass%) = Mass of aromatic compounds produced per hour in the olefin conversion process (kg/hr) / Olefin supply flow rate (kg/hr)
Olefin supply flow rate (kg/hr) = Ethylene flow rate (kg/hr) + Ethylene-equivalent ethanol flow rate (kg/hr) + C4-C6 olefin flow rate (kg/hr)
Ethylene-equivalent ethanol flow rate (kg/hr) = Ethanol flow rate (kg/hr) × Ethylene molecular weight (g/mol) / Ethanol molecular weight (g/mol)

[Production Example 1: Preparation of Zeolite-Containing Catalyst 1]
Clay obtained from 80 parts by mass of proton-type ZSM-5 (silica/alumina molar ratio 40), a zeolite with an intermediate pore size, and 20 parts by mass of alumina was kneaded, and then extruded to obtain extruded bodies with a diameter of 1.6 mm and a length of 4 to 6 mm. The obtained bodies were dried at 350°C for 5 hours and then calcined at 600°C for 5 hours to obtain zeolite-containing catalyst 1.

[Production Example 2: Preparation of Zeolite-Containing Catalyst 2]
Clay obtained from 70 parts by mass of proton-type ZSM-5 (silica/alumina molar ratio of 1000), a zeolite with an intermediate pore size, and 30 parts by mass of silica (moisture content adjusted using colloidal silica and fumed silica) was kneaded, and then extruded to obtain extruded bodies with a diameter of 1.6 mm and a length of 4-6 mm. The obtained bodies were dried at 350°C for 5 hours and then calcined at 600°C for 5 hours to obtain zeolite-containing catalyst 2.

[Production Example 3: Preparation of Zeolite-Containing Catalyst 3]
Clay obtained from 70 parts by mass of proton-type ZSM-5 (silica/alumina molar ratio 280), a zeolite with an intermediate pore size, and 30 parts by mass of silica (moisture content adjusted using colloidal silica and fumed silica) was kneaded, and then extruded to obtain extruded bodies with a diameter of 1.6 mm and a length of 4 to 6 mm. The obtained bodies were dried at 350°C for 5 hours, and then calcined at 600°C for 5 hours to obtain zeolite-containing catalyst 3.

[Production Example 4: Preparation of Zeolite-Containing Catalyst 4]
Clay obtained from 70 parts by mass of proton-type ZSM-5 (silica/alumina molar ratio 280), a zeolite with an intermediate pore size, and 30 parts by mass of silica (moisture content adjusted using colloidal silica and fumed silica) was kneaded and then extruded to obtain extruded bodies with a diameter of 1.6 mm and a length of 4-6 mm. The obtained bodies were dried at 350°C for 5 hours, and a predetermined amount of diammonium hydrogen phosphate aqueous solution was supported on the dried product to obtain a phosphorus-supported product. The obtained phosphorus-supported product was calcined at 600°C for 5 hours in an air atmosphere. The calcined product was filled into a reactor, and a water vapor-nitrogen mixed gas containing 50% by volume of water vapor was supplied and circulated under conditions of a pressure of 0.1 MPaG and a temperature of 600°C for 20 hours to obtain zeolite-containing catalyst 4. At this time, the phosphorus element content in the zeolite-containing catalyst was 0.18% by mass.

[Production Example 5: Preparation of Zeolite-Containing Catalyst 5]
Clay obtained from 70 parts by mass of proton-type ZSM-5 (silica/alumina molar ratio 1000), a zeolite with an intermediate pore size, and 30 parts by mass of silica (moisture content adjusted using colloidal silica and fumed silica) was kneaded and then extruded to obtain extruded bodies with a diameter of 1.6 mm and a length of 4-6 mm. The obtained bodies were dried at 350°C for 5 hours and then calcined at 600°C for 5 hours to obtain a catalyst precursor. The obtained catalyst precursor was stirred in a 0.1 N sodium nitrate aqueous solution for 1 hour, then filtered and washed, and calcined at 600°C for 5 hours to obtain a sodium exchanger. The sodium exchanger was stirred in a 0.01 N silver nitrate aqueous solution for 1 hour, then filtered and washed, and calcined at 600°C for 5 hours to obtain a silver exchanger. Zeolite-containing catalyst 5 was obtained by supplying and circulating a water vapor-air mixed gas containing 50% by volume of water vapor to the silver exchanger under conditions of a pressure of 0.1 MPaG and a temperature of 600°C for 20 hours. At this time, the silver content in the zeolite-containing catalyst was 0.16% by mass.

[Manufacturing Example 6: Method for preparing zeolite-containing catalyst 6]
Clay obtained from 70 parts by mass of proton-type ZSM-5 (silica/alumina molar ratio 1000), a zeolite with an intermediate pore size, and 30 parts by mass of silica (moisture content adjusted using colloidal silica and fumed silica) was kneaded and then extruded to obtain extruded bodies with a diameter of 1.6 mm and a length of 4-6 mm. The obtained bodies were dried at 350°C for 5 hours, and a predetermined amount of diammonium hydrogen phosphate aqueous solution was supported on the dried product to obtain a phosphorus-supported product. The obtained phosphorus-supported product was calcined at 600°C for 5 hours in an air atmosphere. The calcined product was filled into a reactor, and a water vapor-nitrogen mixed gas containing 50% by volume of water vapor was supplied and circulated under conditions of a pressure of 0.1 MPaG and a temperature of 600°C for 20 hours to obtain a zeolite-containing catalyst 6. At this time, the phosphorus element content in the zeolite-containing catalyst was 0.05% by mass.

[Example 1]
(Dehydration process)
Of the total amount of 93.3% by mass ethanol used in Example 1 (10.50 kg/hr), 6.21 kg/hr was used as a dehydration raw material for the dehydration step, and 4.29 kg/hr was used as a bypass raw material directly for the olefin conversion step. In the dehydration step, the above 6.21 kg/hr of ethanol and 3.70 kg/hr of hydrocarbons with 4 or more carbon atoms as shown in Table 1 as composition X were supplied to a fixed-bed single-stage adiabatic reactor filled with zeolite-containing catalyst 1 (silica/alumina molar ratio: 40, alumina binder) at a WHSV of 3.0 and a pressure of 0.20 MPaG to carry out the dehydration step. At this time, the mass ratio of composition X to ethanol was 0.64. 24 hours after the start of the reaction, the inlet temperature of the catalyst bed in the fixed-bed single-stage adiabatic reactor was 480°C, and the outlet temperature of the catalyst bed was 285°C. The concentrations of each component in the resulting dehydration reaction gas are shown in Table 2. The diethyl ether by-product rate was 6.4 mol%.

(Preparation of mixed raw materials)
A mixed raw material was prepared by mixing the dehydration reaction gas obtained in the dehydration process with the bypass raw material described above. The molar ratio of ethylene/(ethanol + 2 × diethyl ether) in the mixed raw material was 1.06, and the molar ratio of olefins with 4 to 6 carbon atoms/ethylene was 0.26.

(Olefin conversion process)
A mixed raw material was supplied to a fixed-bed, single-stage adiabatic reactor packed with zeolite-containing catalyst 2 (silica/alumina molar ratio: 1000, silica binder) at a WHSV of 2.0 and a pressure of 0.15 MPaG, and the olefin conversion process was carried out. After 24 hours from the start of the reaction, the inlet temperature of the catalyst bed in the fixed-bed, single-stage adiabatic reactor was 534°C, the outlet temperature was 546°C, and the temperature difference between the inlet and outlet was 12 K. The average propylene yield from the start to the stop of the reaction was 20.8% by mass, the average aromatic yield was 2.3% by mass, and the coke yield of zeolite-containing catalyst 2 after 48 hours of operation was 238 wt ppm. The reaction results and detailed reaction conditions are shown in Table 3.

[Examples 2-4]
The reaction was carried out in the same manner as in Example 1, except that the dehydration catalyst, the amount of dehydration raw material supplied, and the amount of bypass raw material supplied in the dehydration step were changed as shown in Table 2, and the olefin conversion catalyst and various conditions in the olefin conversion step were changed as shown in Table 3. The results are shown in Tables 2 and 3.
As shown in Examples 1 to 4, by supplying hydrocarbons with four or more carbon atoms to the dehydration process, it was possible to mitigate the temperature drop inside the reactor and suppress the by-product formation of diethyl ether, even in an adiabatic reactor.

[ Reference example 5]
The reaction was carried out in the same manner as in Example 1, except that a single-tube fixed-bed isothermal reactor was used in the dehydration step, and the supply amounts of the dehydration catalyst, dehydration raw materials, and bypass raw materials were changed as shown in Table 2, and the olefin conversion catalyst and various conditions in the olefin conversion step were changed as shown in Table 3. The results are shown in Tables 2 and 3.
In addition, since the temperature change inside the reactor is smaller in an isothermal reactor compared to an adiabatic reactor, the catalyst bed inlet temperature is listed as the reaction temperature in Table 2. In Reference Example 5, the minimum temperature inside the reactor was 341°C for a reaction temperature of 350°C, and the diethyl ether by-product rate was 0.7 mol%.

[Comparative Example 1]
The reaction was carried out in the same manner as in Reference Example 5, except that composition X was not supplied in the dehydration step, and hydrocarbons with 4 or more carbon atoms were supplied to the mixed raw materials in the olefin conversion step, with the mixed raw material ratios shown in Table 3. The results are shown in Tables 2 and 3. In Comparative Example 1, the lowest temperature in the reactor was 329°C at 24 hours after the start of the reaction, relative to the reaction temperature of 350°C in the dehydration step, and the diethyl ether by-product rate was 3.7 mol%.
From a comparison between Reference Example 5 and Comparative Example 1, it was found that even in an isothermal reactor, supplying composition X can suppress temperature fluctuations within the reactor and reduce the by-product formation of diethyl ether.

[Comparative Examples 2-3]
The reaction was carried out in the same manner as in Comparative Example 1, except that the dehydration catalyst, the amount of dehydration raw material supplied, and the amount of bypass raw material supplied in the dehydration step were changed as shown in Table 4, and the olefin conversion catalyst and various conditions in the olefin conversion step were changed as shown in Table 5. The results are shown in Tables 4 and 5. Since composition X was not supplied in the dehydration step, the temperature fluctuation range in the isothermal reactor was 15°C or more, and the by-product rates of diethyl ether were 3.0 mol% and 3.6 mol%, respectively.

[Example 6]
The reaction was carried out in the same manner as in Example 1, except that the dehydration catalyst, the amount of dehydration raw material supplied, and the amount of bypass raw material supplied in the dehydration step were changed as shown in Table 4, and the olefin conversion catalyst and various conditions in the olefin conversion step were changed as shown in Table 5. The results are shown in Tables 4 and 5.
In Example 6, the reaction was evaluated by adding water to 93.3% by mass ethanol without including hydrocarbons with 4 or more carbon atoms in the dehydration raw material. Even with the addition of water, the temperature drop in the adiabatic reactor was mitigated, with the outlet temperature being 326°C compared to the inlet temperature of 480°C 24 hours after the start of the reaction. On the other hand, the rate of diethyl ether by-product increased due to the hydrothermal degradation of the zeolite, which is the dehydration catalyst, and the yield of the target compound, propylene, decreased.

[Comparative Example 4]
In Comparative Example 4, 10.50 kg/hr of 93.3% by mass ethanol was used as the raw material for the dehydration process. The raw material was supplied to a fixed-bed, single-stage isothermal reactor packed with zeolite-containing catalyst 1 (silica/alumina molar ratio: 40, alumina binder) at a WHSV of 4.0 and a pressure of 0.20 MPaG, and the dehydration process was carried out under constant conditions of 350°C. The concentrations of each component in the resulting dehydration reaction gas are shown in Table 4. At this time, the ethanol conversion rate was 98.2 mol%. The dehydration reaction gas obtained in the dehydration process was used as the raw material for the olefin conversion process.

(Olefin conversion process)
A mixed raw material was supplied to a fixed-bed, single-stage adiabatic reactor packed with zeolite-containing catalyst 2 (silica/alumina molar ratio: 1000, silica binder) at a WHSV of 3.0 and a pressure of 0.15 MPaG, and the olefin conversion process was carried out. At this time, the inlet temperature of the catalyst bed was 419°C, the outlet temperature of the catalyst bed was 661°C, and the inlet/outlet temperature difference was 242 K. In Comparative Example 1, the catalytic activity decreased significantly with the progression of the reaction time, and the propylene yield was 6.3% by mass and the aromatic yield was 0.5% by mass after 24 hours, so the reaction was stopped. The reaction conditions are shown in Table 5.
A comparison of the example with Comparative Example 4 revealed that simply connecting the dehydration step and the olefin conversion step, and supplying an excess of ethanol-derived ethylene to the olefin conversion step relative to ethanol and diethyl ether, makes it impossible to control the temperature inside the adiabatic reactor, accelerating catalyst degradation and resulting in a decrease in the yield of the target compound.

[Comparative Example 5]
In Comparative Example 5, the dehydration step was omitted, and the entire amount of ethanol was directly supplied to the olefin conversion step. 93.3% by mass ethanol was supplied to a fixed-bed, single-stage adiabatic reactor packed with zeolite-containing catalyst 2 (silica/alumina molar ratio: 1000, silica binder) to a WHSV of 3.0 and a pressure of 0.15 MPaG, and the olefin conversion step was carried out. At this time, the inlet temperature of the catalyst bed was 592°C, the outlet temperature of the catalyst bed was 488°C, and the temperature difference between inlet and outlet was 104 K. The average propylene yield from the start to the stop of the reaction was 11.4% by mass, the average aromatic yield was 0.9% by mass, and the coke yield of zeolite-containing catalyst 2 after 48 hours of operation was 379 wt ppm. Details of the reaction results and reaction conditions are shown in Table 5.
A comparison of the example with Comparative Example 5 revealed that when ethanol is directly supplied to the olefin conversion step without a dehydration step, the temperature inside the adiabatic reactor cannot be controlled due to the endothermic reaction, the reactor outlet temperature decreases, catalyst degradation is accelerated, and the yield of the target compound decreases.

1, 2…Reactors, 3…First distillation column, 4…Second distillation column, 5…Third distillation column, 6…Fourth distillation column, 7…Fifth distillation column, 8…Condenser

Claims (32)

A dehydration step involves supplying a composition X containing a hydrocarbon having 4 or more carbon atoms and a dehydration raw material containing ethanol to an adiabatic reactor, and in the adiabatic reactor, the ethanol is dehydrated using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene.
An olefin conversion step is to bring a mixed raw material containing the dehydrated reaction gas and a bypass raw material containing ethanol into contact with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms.
Includes,
The molar ratio of ethylene/(ethanol + 2 × diethyl ether) in the aforementioned mixed raw materials is 0.5 to 1.93 .
Methods for converting ethanol. The reaction gas is separated into a fraction A mainly containing hydrocarbons having 1 to 3 carbon atoms and a fraction B mainly containing hydrocarbons having 4 to 6 carbon atoms,
The method for converting ethanol according to claim 1, wherein at least a portion of the fraction B is supplied as composition X into the reactor in the dehydration step. The method for converting ethanol according to claim 1, wherein the mass ratio of composition X to ethanol (composition X/ethanol) in the dehydration step is 0.10 to 4.0. The method for converting ethanol according to claim 1, wherein the content of hydrocarbons having 4 to 6 carbon atoms in composition X is 50% by mass or more. The method for converting ethanol according to claim 1, wherein the supply temperature of composition X into the reactor is 200°C to 530°C. The method for converting ethanol according to claim 1 , wherein the mixed raw materials contain diethyl ether. The method for converting ethanol according to claim 1 , wherein the content of diethyl ether in the mixed raw materials is 10% by mass or less. The method for converting ethanol according to claim 1 , wherein the content of diethyl ether in the dehydration reaction gas is 10% by mass or less. The method for converting ethanol according to claim 1 , wherein the mixed raw materials contain hydrocarbons having 4 to 6 carbon atoms. The method for converting ethanol according to claim 1 , wherein the molar ratio of olefins having 4 to 6 carbon atoms in the mixed raw materials is 0.14 or more and 3.5 or less. The method for converting ethanol according to claim 1 , wherein the reactor in the olefin conversion step is an adiabatic reactor. The method for converting ethanol according to claim 11 , wherein the adiabatic reactor in the olefin conversion step is a fixed-bed single-stage adiabatic reactor. The method for converting ethanol according to claim 1 , wherein the dehydration catalyst is a solid acid catalyst. The method for converting ethanol according to claim 13 , wherein the solid acid catalyst is a zeolite-containing catalyst. The method for converting ethanol according to claim 14 , wherein the silica/alumina molar ratio of the zeolite in the zeolite-containing catalyst is 20 to 2000. The method for converting ethanol according to claim 15 , wherein the zeolite-containing catalyst contains at least one element selected from the group consisting of phosphorus and elements belonging to Group 11 of the periodic table. The method for converting ethanol according to claim 1 , wherein the olefin conversion catalyst is a solid acid catalyst. The method for converting ethanol according to claim 17 , wherein the solid acid catalyst is a zeolite-containing catalyst. The method for converting ethanol according to claim 18 , wherein the silica/alumina molar ratio of the zeolite in the zeolite-containing catalyst is 20 to 2000. The method for converting ethanol according to claim 19 , wherein the zeolite-containing catalyst contains at least one element selected from the group consisting of phosphorus and elements belonging to Group 11 of the periodic table. The method for converting ethanol according to claim 1, further comprising a cooling step after the olefin conversion step, in which the reaction gas is cooled and separated into a fraction K mainly containing hydrocarbons having 1 to 6 carbon atoms and a fraction L mainly containing water, hydrocarbons having 7 or more carbon atoms and aromatic compounds. After the olefin conversion step, the reaction gas is cooled and separated into a fraction K mainly containing hydrocarbons having 1 to 6 carbon atoms and a fraction L mainly containing water, hydrocarbons having 7 or more carbon atoms, and aromatic compounds in a cooling step.
A separation step is performed to separate the aforementioned fraction K into fraction A, which mainly contains hydrocarbons having 1 to 3 carbon atoms, and fraction B, which mainly contains hydrocarbons having 4 to 6 carbon atoms.
A method for converting ethanol according to claim 1, including the following: The method for converting ethanol according to claim 22 , wherein the reactor in the olefin conversion step is an adiabatic reactor. The method for converting ethanol according to claim 23 , wherein the reactor in the dehydration step is an adiabatic reactor. A dehydration step involves supplying a composition X containing a hydrocarbon having 4 or more carbon atoms and a dehydration raw material containing ethanol to an adiabatic reactor, and in the adiabatic reactor, the ethanol is dehydrated using a dehydration catalyst to obtain a dehydration reaction gas containing ethylene.
An olefin conversion step is to bring a mixed raw material containing the dehydrated reaction gas and a bypass raw material containing ethanol into contact with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms.
Includes,
The molar ratio of ethylene/(ethanol + 2 × diethyl ether) in the aforementioned mixed raw materials is 0.5 to 1.93 .
A method for producing hydrocarbons. A propylene separation step for separating a fraction mainly containing propylene from the reaction gas obtained by the ethanol conversion method described in claim 1 ,
A method for producing propylene, including the method described above. A fraction mainly containing aromatic compounds is separated from the reaction gas obtained by the ethanol conversion method described in claim 1 .
A method for producing aromatic compounds, including An adiabatic reactor is provided in which a dehydration reaction is carried out with a dehydration catalyst to dehydrate a dehydrated raw material containing ethanol, and a dehydrated reaction gas containing ethylene is obtained.
A reactor comprising contacting a mixed raw material containing the dehydration reaction gas and a bypass raw material containing ethanol with an olefin conversion catalyst to obtain a reaction gas containing an olefin having 3 or more carbon atoms,
A composition X supply line is used to introduce a composition X containing a hydrocarbon with four or more carbon atoms into a reactor that obtains the dehydration reaction gas.
Includes,
The molar ratio of ethylene/(ethanol + 2 × diethyl ether) in the aforementioned mixed raw materials is 0.5 to 1.93 .
Ethanol conversion device. The apparatus further includes a separation device for separating the reaction gas into a fraction A mainly containing hydrocarbons having 1 to 3 carbon atoms and a fraction B mainly containing hydrocarbons having 4 to 6 carbon atoms.
The ethanol conversion apparatus according to claim 28 , wherein at least a portion of the fraction B is supplied as the composition X to the composition X supply line. The ethanol conversion apparatus according to claim 29, comprising a cooler for cooling the reaction gas and separating it into a fraction K mainly containing hydrocarbons having 1 to 6 carbon atoms and a fraction L mainly containing water, hydrocarbons having 7 or more carbon atoms and aromatic compounds. The ethanol conversion apparatus according to claim 30 , wherein the separation device separates the fraction K separated by the cooler. The ethanol conversion apparatus according to claim 28 , wherein the reactor used to obtain the reaction gas containing the olefin having 3 or more carbon atoms is an adiabatic reactor.