JP7628399B2 - Method for co-producing methanol and methane and equipment for co-producing methanol and methane - Google Patents

Description

The present invention relates to a method and equipment for co-producing methanol and methane using hydrogen and carbon dioxide as raw materials.

In recent years, as a measure to combat global warming, attention has been focused on carbon-neutral fuels, which do not substantially increase the concentration of carbon dioxide in the atmosphere even when burned.

Methane or methanol can be obtained by recovering carbon dioxide from exhaust gases generated in industrial processes and thermal power plants, and reacting it with hydrogen obtained by electrolysis using electricity generated by renewable energy sources such as solar and wind power. Methane or methanol obtained by this method can be considered a carbon-neutral fuel that does not contribute to global warming, since no additional carbon dioxide is produced when it is burned.

The methanation reaction (Equation 1) in which carbon dioxide and hydrogen are reacted to obtain methane is known.
(Equation 1)
CO ₂ +4H ₂ → CH ₄ +2H ₂ O

Patent Document 1 discloses a method for methanating a gas containing CO and _H2 , characterized in that a methanation reactor is used in which a Cu-Zn-based low-temperature shift catalyst is arranged on the upstream side and a methanation catalyst is arranged on the downstream side when methanating a gas containing CO and _H2 . Since the CO shift reaction (formula 2) proceeds in the upstream low-temperature shift reactor, most of the carbon monoxide contained in the raw material gas reacts with water vapor and is converted to carbon dioxide, and it is considered that the methanation reaction of carbon dioxide proceeds on the downstream methanation catalyst.
(Equation 2)
CO+ _H2O → _CO2 + _H2

Methanation reactions have long been used to remove carbon monoxide and carbon dioxide from hydrogen for ammonia synthesis, and catalysts carrying Ni or Ru are known to exhibit high activity (Non-Patent Documents 1 and 2).

The methanation reaction, in which carbon dioxide is reacted with hydrogen to obtain methane, is an industrially established technology (e.g., Non-Patent Document 3), but there is still room for improvement in terms of producing carbon-neutral fuels.

As shown in formula 1, the methanation reaction in which carbon dioxide reacts with hydrogen to obtain methane produces 1 mol of methane from 4 mol of hydrogen. The calorific value (higher heating value, the same applies below) of 4 mol of hydrogen is 1,143.3 kJ, and the calorific value of 1 mol of methane is 890.3 kJ. Therefore, even if the reaction proceeds with a 100% yield as per the theoretical formula, the calorific value of the methane obtained is only 77.9% of the calorific value of the hydrogen used as the raw material. The remainder is released as reaction heat and cannot normally be used, so approximately 22% of the energy is lost in the process of converting hydrogen to methane.

A reaction (formula 3) in which carbon dioxide and hydrogen are reacted to obtain methanol is also known (for example, Patent Document 2).
(Equation 3)
CO ₂ + 3H ₂ → CH ₃ OH + H ₂ O

In this reaction, 1 mol of methanol is produced from 3 mol of hydrogen. The calorific value (higher calorific value, same below) of 3 mol of hydrogen is 857.5 kJ, and the calorific value of 1 mol of methanol is 726.1 kJ. Therefore, if the reaction proceeds with a 100% yield according to the theoretical formula, the calorific value of the methanol obtained will be 84.7% of the calorific value of the raw material hydrogen, which is more efficient than converting it into methane.

This high thermal efficiency of conversion also means that the heat of reaction (enthalpy change) of the reaction to obtain methanol by reacting carbon dioxide with hydrogen is small, which means that the Gibbs energy change of the reaction is small, meaning that the reaction is unlikely to proceed in equilibrium.

For example, when a gas with a _CO2 : _{H2 ratio} of 1:4 is subjected to a methanation reaction at 250°C and 5 MPa to reach an equilibrium composition, 99.5% of the _CO2 is converted to methane. In contrast, when a gas with a _CO2 : _H2 ratio of 1:3 is subjected to a methanol synthesis reaction at the same conditions of 250°C and 5 MPa to reach an equilibrium composition, only about 20% of the _CO2 is converted to methanol.

As described above, since it is difficult to obtain a high equilibrium conversion rate in the reaction of synthesizing methanol by the reaction of carbon dioxide with hydrogen, a method for synthesizing methanol has been proposed in which at least a portion of carbon dioxide is converted into carbon monoxide in advance by a reverse shift reaction (Equation 4), and the generated water is removed before passing the resulting mixture through a methanol synthesis catalyst (Non-Patent Document 4, Patent Document 3).
(Equation 4)
CO ₂ + H ₂ → CO + H ₂ O

The reaction (formula 5) for obtaining methanol from carbon monoxide and hydrogen generates a larger amount of heat than the reaction for obtaining methanol from carbon dioxide and hydrogen, due to the endothermic heat of the reverse shift reaction. Accordingly, the conversion rate of carbon monoxide to methanol at equilibrium is higher than that of the methanol synthesis reaction from carbon dioxide. For example, when a gas with a CO:H ₂ ratio of 1:2 is subjected to a methanol synthesis reaction under conditions of 250° C. and 5 MPa to obtain an equilibrium composition, 58% of CO is converted to methanol.
(Equation 5)
CO+ _2H2 → _CH3OH

The reverse shift reaction is an endothermic reaction, and the higher the temperature, the higher the conversion rate of carbon dioxide to carbon monoxide. For example, when a gas with a CO ₂ :H ₂ ratio of 1:3 is subjected to the reverse shift reaction, the conversion rate of carbon dioxide to carbon monoxide is only 16% at 250° C., but increases to 29% at 350° C. and 43% at 450° C. Therefore, in order to sufficiently proceed with the reverse shift reaction, the reaction must be carried out at a high temperature, which requires a high-temperature heat source.

On the other hand, the methanol synthesis reaction is an exothermic reaction, and the higher the temperature, the lower the conversion rate. Therefore, it is common to use a heat exchange reactor to carry out the reaction at around 250°C, and it is generally impossible to recover waste heat above 350°C. It is possible to cover the endothermic heat of the reverse shift reaction by burning hydrogen, but this inevitably reduces the efficiency of converting hydrogen into methanol.

Japanese Unexamined Patent Publication No. 60-235893 Japanese Patent Application Publication No. 7-39755 U.S. Pat. No. 8,198,338

Chemical Process Journal, edited by the Society of Chemical Engineers, 1970, p.153 Catalysis Society of Japan, Catalyst Handbook, 2008, p.535 Kawagoe, Matsuda, Matsushima and Uematsu, Hitachi Review, Vol. 68, No. 10, 1986, p. 73 S.-J. Uhm et al., Industrial and Engineering Chemistry Research, vol. 38, 1999, p. 1808.

In view of the above problems, the problem that the present invention aims to solve is to provide a method and equipment for co-producing methane and methanol with improved conversion efficiency while suppressing equipment costs when producing methane and methanol from hydrogen and carbon dioxide.

The characteristic configuration of the method for producing methanol and methane according to the present invention is as follows:
A process for co-producing methanol and methane from hydrogen and carbon dioxide, comprising the steps of:
(a) obtaining a synthesis gas containing hydrogen, carbon monoxide, carbon dioxide and water vapor from a raw material gas containing hydrogen and carbon dioxide by a reverse shift reaction;
(b) cooling the synthesis gas to separate water;
(c) passing the synthesis gas from which water has been separated through a methanol synthesis catalyst to synthesize methanol;
(d) cooling the gas obtained in step (c) to separate methanol;
(e) passing a raw material gas containing hydrogen and carbon dioxide through a methanation catalyst to synthesize methane;
At least a part of the synthesis gas from which methanol has been separated in the step (d) is used as a raw material gas for the methanation reaction in the step (e);
Step (e) is carried out only after step (d);
The reaction heat generated in the step (e) is used as a heat source for the step (a) via a heat exchanger.
The methanol and methane co-production equipment according to the present invention has the following characteristic configuration:
A facility for co-producing methanol and methane from hydrogen and carbon dioxide, comprising:
a reverse shift reaction section for obtaining a synthesis gas containing hydrogen, carbon monoxide, carbon dioxide and water vapor from a raw material gas containing hydrogen and carbon dioxide by a reverse shift reaction;
a water separation section that cools the synthesis gas and separates water from it;
a methanol synthesis unit that synthesizes methanol by passing the synthesis gas from which water has been separated through a methanol synthesis catalyst;
a methanol separation section for cooling the gas sent from the methanol synthesis section and separating methanol;
a methanation reaction section that synthesizes methane by passing a raw material gas containing hydrogen and carbon dioxide through a methanation catalyst;
a heat supply section that supplies reaction heat generated in the methanation reaction section to the reverse shift reaction section via a heat exchanger;
The present invention is configured such that at least a part of the synthesis gas sent out from the methanol separation section is supplied as a raw material gas to the methanation reaction section , and the methanation reaction section is disposed only at the downstream of the methanol separation section .

According to this characteristic configuration, when obtaining methanol from a raw material gas containing hydrogen and carbon dioxide, a part of carbon dioxide is converted to carbon monoxide in advance by the reverse shift reaction, so that the yield of methanol is improved. Furthermore, the reverse shift reaction is usually performed at 350° C. or higher, preferably 450° C. or higher, but in the methanol synthesis, exhaust heat at this temperature cannot be obtained. In the method and equipment for co-producing methane and methanol of the present invention, the process for synthesizing methane is performed only after the process for separating methanol, and the heat generated by methanation is utilized as a heat source for the reverse shift reaction via a heat exchanger, so that the efficiency of conversion of hydrogen to products (methane and methanol) is increased.
According to this characteristic configuration, when obtaining methanol from a raw material gas containing hydrogen and carbon dioxide, at least a part of the synthesis gas from which methanol is separated is used as the raw material gas for the methanation reaction, so that the amount of unreacted gas that is usually required in the methanol synthesis process to be recycled to the raw material gas is reduced, and the synthesis gas from which methanol is separated can be effectively used as the raw material gas for the methanation reaction. When the entire amount of the synthesis gas from which methanol is separated is used as the raw material gas for the methanation reaction, it is not necessary to recycle the unreacted gas to the raw material gas for the methanol synthesis, and therefore the equipment cost can be significantly reduced.

A further characteristic feature of the methanol and methane co-production equipment according to the present invention is that it includes a flow rate adjusting section that adjusts the flow rate of the synthesis gas supplied from the methanol separation section to the methanation reaction section.

A further characteristic feature of the method for co-producing methanol and methane according to the present invention is that at least a part of the synthesis gas from which methanol has been separated in the step (d) is mixed with the feed gas for the reverse shift reaction in the step (a).
In addition, a further characteristic configuration of the methanol and methane co-production equipment according to the present invention is configured to return at least a part of the synthesis gas sent from the methanol separation section to the reverse shift reaction section as a raw material gas,
The flow rate adjusting section adjusts the flow rate of the synthesis gas supplied from the methanol separation section to the reverse shift reaction section.

According to this characteristic configuration, the production amounts of methanol and methane can be selected arbitrarily as long as the heat generated in the methanation reaction process can cover the heat absorbed in the reverse shift reaction process, and methanol and methane can be co-produced economically.

FIG. 1 is a block flow diagram showing one embodiment of a method and equipment for co-producing methanol and methane according to the present invention. FIG. 2 is a block flow diagram showing another embodiment of the method and facility for co-producing methanol and methane according to the present invention. FIG. 1 is a process flow diagram showing one embodiment of a method and equipment for co-producing methanol and methane according to the present invention. FIG. 1 is a process flow diagram showing a method and facility for co-producing methanol and methane other than the method of the present invention. FIG. 1 is a process flow diagram showing one embodiment of a method and equipment for co-producing methanol and methane according to the present invention. FIG. 1 is a process flow diagram showing a method and facility for co-producing methanol and methane other than the method of the present invention.

[Embodiment]
Hereinafter, an embodiment of the method and equipment for co-producing methanol and methane will be described. FIG. 1 is a block flow diagram showing the method and equipment for co-producing methanol and methane of the present invention. The method for co-producing methanol and methane according to this embodiment includes a step of obtaining a synthesis gas containing hydrogen, carbon monoxide, carbon dioxide and steam from a raw material gas containing hydrogen and carbon dioxide by a reverse shift reaction (reverse shift reaction step), a step of cooling the synthesis gas and separating water (water separation step), a step of synthesizing methanol by passing the synthesis gas from which water has been separated through a methanol synthesis catalyst (methanol synthesis step), a step of cooling the gas obtained in the methanol synthesis step and separating methanol (methanol separation step), and a step of synthesizing methane by passing the raw material gas containing hydrogen and carbon dioxide through a methanation catalyst (methanation reaction step), and the reaction heat generated in the methanation reaction step is used as a heat source for the reverse shift reaction step.
The methanol and methane co-production facility according to this embodiment includes a reverse shift reaction section 1, a water separation section 2, a methanol synthesis section 3, a methanol separation section 4, and a methanation reaction section 5 which correspond to each step in the above-mentioned co-production method, and also includes a heat supply section 6 which supplies reaction heat generated in the methanation reaction section 5 to the reverse shift reaction section 1.

In the reverse shift reaction process (reverse shift reaction section 1), the raw material gas containing carbon dioxide and hydrogen is preheated by supplying reaction heat generated in the methanation reaction process described below from the heat supply section 6, and is brought into contact with the reverse shift catalyst to generate carbon monoxide and water vapor through the reverse shift reaction of carbon dioxide and hydrogen. The heat supply section 6 is, for example, a heat exchanger that exchanges heat between the raw material gas and gas whose temperature has been increased by the methanation reaction.

The carbon dioxide and hydrogen used as raw materials may be produced by any method, so long as they have a purity and properties that do not interfere with the reverse shift reaction. Hydrogen may be electrolytic hydrogen obtained by electrolyzing water, for example. Carbon dioxide may be carbon dioxide recovered from combustion exhaust gas by a known carbon dioxide recovery method such as the amine absorption method, or carbon dioxide recovered from biogas obtained by methane fermentation of organic matter.

If the carbon dioxide or hydrogen contains sulfur, halogen compounds, siloxane compounds, heavy hydrocarbons, etc., these may cause deterioration of the reverse shift catalyst or the downstream methanol synthesis catalyst, so it is preferable to remove these, if necessary, before subjecting them to the reaction.

As a reverse shift catalyst, known CO shift catalysts such as copper-zinc catalyst and iron-chromium catalyst can be used.

The preheating temperature is limited by the balance with the heat generated in the methanation reaction process, but is usually set to 300°C or higher and 550°C or lower, and preferably 350°C or higher and 500°C or lower. If it is within this range, the conversion rate of carbon dioxide to carbon monoxide is ensured, and the heat generated in the methanation reaction process can easily cover the heat required for preheating.

When the reverse shift reaction is carried out in an adiabatic reactor, the temperature decreases as the reaction proceeds, and the conversion rate of carbon dioxide to carbon monoxide decreases accordingly. Therefore, preheating and reaction may be repeated in multiple stages as necessary.

In the water separation step (water separation section 2), the gas containing hydrogen, carbon monoxide, carbon dioxide and water vapor obtained by the reverse shift reaction is cooled, and the water vapor is separated into water. Since the gas after the reverse shift reaction is at a sufficiently high temperature, it is preferable to recover its sensible heat and use it, for example, for heat exchange with the raw material gas containing carbon dioxide and hydrogen to be subjected to the reverse shift reaction, thereby preheating it.

If the temperature is not sufficiently reduced by heat exchange with the raw gas containing carbon dioxide and hydrogen to be subjected to the reverse shift reaction, the gas is further cooled by means of cooling water or air cooling, preferably to 50°C or less, more preferably to 40°C or less, and the condensed water is separated. For example, if the amount of water vapor remaining in the gas is reduced by cooling to a lower temperature using a refrigerator or the like before separating the water, the amount of methanol obtained in the subsequent methanol synthesis process will increase to some extent, but cooling with cooling water or the like is usually sufficient.

In the methanol synthesis process (methanol synthesis section 3), the hydrogen, carbon monoxide, and carbon dioxide from which the water has been separated, as well as a gas containing a trace amount of water vapor, are brought into contact with a methanol synthesis catalyst to produce methanol.

As a methanol synthesis catalyst, known copper-zinc catalysts, chromium-zinc catalysts, copper-chromium-zinc catalysts, etc. can be used.

The temperature at which the reaction mixture is brought into contact with the methanol synthesis catalyst is preferably 200°C or higher and 350°C or lower, and more preferably 220°C or higher and 280°C or lower. If the temperature is within the above range, a sufficient reaction rate and conversion rate to methanol can be ensured, so that the amount of methanol produced can be ensured without using an excessive amount of catalyst.

Since the methanol synthesis reaction generates a certain amount of heat, it is preferable to use a heat exchange type reactor as the methanol synthesis reactor, which allows the reaction to proceed while removing the generated heat.

In the methanol separation step (methanol separation section 4), the gas obtained in the methanol synthesis step, which contains methanol and unreacted hydrogen, carbon monoxide, and carbon dioxide, is cooled to separate and recover methanol as a liquid. Since the gas after the methanol synthesis step is at a sufficiently high temperature, it is preferable to recover its sensible heat and use it, for example, to exchange it with the gas to be used for methanol synthesis and to preheat it.

Since methanol has a certain vapor pressure even at room temperature, the amount of methanol recovered can be increased by cooling it to below room temperature using a refrigerator and heat exchanger, in addition to cooling it by heat exchange, water cooling, or air cooling. Methanol is separated by cooling it to preferably below 20°C, more preferably below 10°C.

In the methanation reaction step (methanation reaction section 5), the gas containing unreacted hydrogen, carbon monoxide, and carbon dioxide after separation of the methanol is contacted with a methanation catalyst to produce methane.

The methanation catalyst used in the methanation reaction process can be a known methanation catalyst containing Ni, Ru, or the like.

The inlet temperature when contacting the methanation catalyst is preferably 200°C or higher and 350°C or lower, and more preferably 225°C or higher and 275°C or lower. If it is within the above range, a sufficient reaction rate is easily obtained, making it easy to proceed with the methanation reaction without using an excessive amount of catalyst, and since the outlet temperature of the methanation reaction does not become too high, it is easy to ensure the durability of the catalyst.

Since the methanation reaction generates a relatively large amount of heat, the gas temperature rises as the reaction proceeds, and the equilibrium conversion rate decreases accordingly. Therefore, it is usually difficult to obtain the desired conversion rate in a single-stage reaction. On the other hand, if a heat exchange type reactor is used, it becomes difficult to extract the high-temperature heat required for the reverse shift reaction. Therefore, it is preferable to use an adiabatic reactor on the inlet side, and cool the outlet gas whose temperature has risen due to the reaction heat by heat exchange with the gas to be used for the reverse shift reaction (i.e., use the reaction heat generated in the methanation reaction process as a heat source for the reverse shift reaction process), and then introduce it into the next-stage reactor. Adiabatic reactors may be connected in multiple stages via a heat exchanger for cooling, and at least one adiabatic reactor on the inlet side and at least one heat exchange type reactor on the outlet side may be connected via a heat exchanger for cooling.

Since the methanation reaction generates a relatively large amount of heat, thermal degradation of the catalyst can be a problem in some cases. The gas from the reactor outlet side can be returned to the reactor inlet side to dilute the gas used in the reaction. When this reactor configuration is used, the dilution effect suppresses temperature rise, improving the durability of the catalyst. In addition, the lower reactor outlet temperature has the effect of increasing the equilibrium conversion rate, so it may be possible to reduce the number of reactor stages compared to a simple multi-stage reactor configuration.

The gas after the methanation reaction is cooled and the water is separated to obtain gas mainly composed of methane.

The reaction pressure is preferably 3 MPa or more and 10 MPa or less, and more preferably 4 MPa or more and 7 MPa or less. If the reaction pressure is in this range, it is possible to obtain methanol at a molar ratio to methane of about 0.5 to 1 while suppressing equipment costs.

In the methanol and methane co-production method and equipment shown in Figure 1, methanol is first synthesized based on synthesis gas obtained from a feed gas containing carbon dioxide and hydrogen supplied to the reverse shift reaction section 1, and methane is synthesized using the unreacted synthesis gas remaining after separation. The molar ratio of methanol to methane produced is determined by the reaction pressure and the progress of the reverse shift reaction, and is usually in the range of 3:7 to 5:5.

In the method of this embodiment, the entire amount of unreacted synthesis gas after the methanol synthesis reaction is used as a raw material for the methanation reaction, so there is no need to select extremely high pressures, such as 20 MPa, as are used in conventional methanol synthesis to increase the methanol conversion rate, and there is no need for expensive equipment such as a recycle compressor that returns unreacted synthesis gas to the inlet side of the methanol synthesis reaction.

In the present embodiment of the method and equipment for co-producing methanol and methane, the molar ratio of methanol to methane produced varies depending on the reaction conditions. When obtaining methanol by the reaction of carbon dioxide with hydrogen, three times as much hydrogen is required in terms of molar ratio to carbon dioxide, and when obtaining methane, four times as much hydrogen is required in terms of molar ratio to carbon dioxide. Therefore, in the present embodiment of the method for co-producing methanol and methane, the ratio of carbon dioxide to hydrogen supplied to the reverse shift reaction is set to a molar ratio of hydrogen to carbon dioxide of 3 to 4, but when methane is used as a raw material for city gas, it is not preferable for a large amount of hydrogen or carbon dioxide to remain. For example, when the molar ratio of methanol to methane produced is 4:6, the concentration of gases other than methane contained in the gas after the methanation reaction can be reduced by supplying a mixed gas to the reverse shift reaction section 1 so that the molar ratio of hydrogen to carbon dioxide is 3.6.

Figure 2 is a block flow diagram showing a method and equipment for co-producing methanol and methane according to another embodiment of the present invention. The method and equipment for co-producing methanol and methane according to this embodiment also have a reverse shift reaction step (reverse shift reaction section 1), a water separation step (water separation section 2), a methanol synthesis step (methanol synthesis section 3), a methanol separation step (methanol separation section 4), and a methanation reaction step (methanation reaction section 5). However, unlike the embodiment shown in Figure 1, the synthesis gas after separation of methanol in the methanol separation step (methanol separation section 4) passes through a flow rate adjustment section 7, and most of the synthesis gas is returned to the inlet of the reverse shift reaction section 1, and the remainder is mixed with a separately prepared raw material gas containing hydrogen and carbon dioxide and used as a raw material for the methanation reaction step. The flow rate adjustment section 7 is configured to be able to arbitrarily adjust the amount of synthesis gas returned to the reverse shift reaction section 1 and the amount of synthesis gas supplied to the methanation reaction section 5.

In this embodiment, the ratio of methanol to methane production can be set as desired, as long as the heat generated in the methanation reaction process can cover the heat absorbed in the reverse shift reaction.

In the method of this embodiment, a portion of the carbon dioxide is converted to carbon monoxide by the reverse shift reaction, so the methanol conversion rate in a single pass is high. This means that the scale of equipment such as a recycle compressor that returns unreacted synthesis gas to the inlet side is smaller than in conventional known methods and equipment. In addition, because the methanol conversion rate in a single pass is high, the proportion of unreacted gas that is recycled is reduced, which reduces the flow rate of synthesis gas introduced into the methanol synthesis catalyst, and therefore the amount of methanol synthesis catalyst can be reduced, and the costs of the catalyst and reactor can be reduced.

In methanol synthesis equipment with unreacted gas recycling, a portion of the unreacted synthesis gas is usually extracted from the system as purge gas to prevent the accumulation of inert components. This may include light hydrocarbons such as methane, which can be used as methanation feedstock. In the present embodiment of the method and equipment for co-producing methanol and methane, the unreacted synthesis gas can be mixed with a feedstock gas containing hydrogen and carbon dioxide prepared separately from the feedstock used in the reverse shift reaction to be used as the feedstock for the methanation reaction process, thereby increasing the conversion efficiency from hydrogen to the products methanol and methane.

[Examples and Comparative Examples]
An example of a trial calculation based on a process calculation is shown below. The pressure is 5 MPa, and pressure loss and heat radiation loss in each device and piping are not taken into consideration. Note that FIG. 3 is a process flow diagram showing one embodiment of the method and equipment for co-producing methanol and methane according to the present invention.

The raw material gas is supplied to the reverse shift reaction section 1 at a temperature of 25°C and a flow rate of 1 mol/s of carbon dioxide and 3.6 mol/s of hydrogen. In the reverse shift reaction section 1, the raw material gas is heated to 350°C in the heat exchanger 311 by heat exchange with the gas after the reverse shift reaction described below. Then, the raw material gas is passed to the reverse shift reactor 312, where a part of the carbon dioxide is converted to carbon monoxide by the reverse shift reaction. The gas whose temperature has been reduced by the reverse shift reaction is heated to 520°C in the heat exchanger 313 (corresponding to the heat supply section) by heat exchange with the gas after the methanation reaction. Then, the gas is passed to the reverse shift reactor 314, where the reverse shift reaction is further advanced to further increase the proportion of carbon monoxide (reverse shift reaction process). The outlet gas of the reverse shift reactor 314 is cooled to 150°C by heat exchange with the raw material gas in the heat exchanger 315 (= the high temperature side of the heat exchanger 311) and sent to the water separation section 2.

In the water separation section 2, the gas after the reverse shift reaction is further cooled to 40°C using cooling water in a heat exchanger 321. The water condensed by cooling is separated from the synthesis gas in a gas-liquid separation drum 322 (water separation process).

In the methanol synthesis section 3, the synthesis gas from which water has been separated in the water separation section 2 is heated to 150°C in the heat exchanger 331 by heat exchange with the gas after the methanol synthesis reaction described later, and further heated to 250°C in the heat exchanger 332 by heat exchange with the recycled gas after the methanation reaction described later, and then passed to the methanol synthesis reactor 333 to synthesize methanol from the synthesis gas. It is not necessarily necessary to raise the temperature to 250°C by heat exchange with the recycled gas after the methanation reaction. In a normal methanol synthesis reaction, the inlet gas of the methanol synthesis reactor is preheated to a temperature required to start the methanol synthesis reaction, for example, about 200°C, by heat exchange between the outlet gas and inlet gas of the methanol synthesis reactor, and the temperature is gradually raised to a temperature appropriate for the methanol synthesis reaction by reaction and heat exchange in the methanol synthesis reactor. However, it is advantageous to raise the temperature to 250°C by heat exchange with the recycled gas after the methanation reaction, in that the reaction starts quickly at a temperature appropriate for the methanol synthesis reaction.

The methanol synthesis reactor 333 is a heat exchange type reactor, in which the reaction proceeds while maintaining a temperature of approximately 250°C while removing the heat generated by the methanol synthesis reaction, and the methanol synthesis reaction proceeds to an equilibrium composition of 250°C (methanol synthesis process). The heat generated is recovered as high-pressure steam. The gas after the methanol synthesis reaction is heat-recovered to 150°C in the heat exchanger 334 (the high-temperature side of the heat exchanger 331) and sent to the methanol separation section 4.

In the methanol separation section 4, the gas after the methanol synthesis reaction is cooled to 40°C using cooling water in a heat exchanger 341, and further cooled to below room temperature using a refrigerator and a heat exchanger (not shown), and the produced methanol is separated in a gas-liquid separation drum 342 (methanol separation process).

In the methanation reaction section 5, the entire amount of the synthesis gas from which methanol has been separated in the methanol separation section 4 is mixed with the gas branched from the outlet of the heat exchanger 352 described later, and is passed through the methanation reactor 351 at 250°C to carry out the methanation reaction of the synthesis gas (methanation reaction process). The methanation reactor 351 is an adiabatic reactor, and the temperature rises as methanation progresses, and the methanation reaction proceeds up to an equilibrium composition of 600°C. The heat exchanger 352 is the high-temperature side (heat dissipation side) of the heat exchanger 313, and the gas after the methanation reaction is cooled to 479°C by heat exchange, and 72.3% is returned to the inlet side as recycled gas using a recycle compressor (not shown). The recycled gas is first cooled to 416°C by heat exchange with gas on the inlet side of the methanol synthesis catalyst in heat exchanger 353 (the high temperature side of heat exchanger 332), and further cooled to 350°C while recovering heat as high pressure steam by heat exchange with water in heat exchanger 354, and mixed with the synthesis gas from which methanol has been separated. The remaining 27.7% is passed through heat exchanger 355, where it is cooled to 250°C while recovering heat as high pressure steam, and sent to methanation reactor 356. Methanation reactor 356 is a heat exchange type reactor, in which the reaction proceeds while maintaining the temperature at approximately 250°C while removing heat generated by the reaction, and the methanation reaction proceeds until the equilibrium composition reaches 250°C, and the heat is recovered as high pressure steam. After the reaction, the gas is cooled to 150°C in heat exchanger 357 to obtain low-pressure steam, which is then further cooled with cooling water in heat exchanger 358. Water is separated in gas-liquid separation drum 359 to obtain methane-based gas.

The temperatures and flow rates at key points in the process are shown in Table 1.

The production rates of methanol and methane were 0.400 mol/s and 0.597 mol/s, respectively. The ratio of the calorific value of the products (methanol and methane) to the raw hydrogen was 79.9%. The composition of the main methane gas produced after dehydration was 97.66% methane, 1.86% hydrogen, and 0.48% carbon dioxide. As shown in Table 1, the inlet gas flow rate of the methanol synthesis catalyst was 4.118 mol/s. When the designed catalyst amount of the methanol synthesis catalyst is designed at a gas hourly space velocity (GHSV) of 2000 per hour, 166 liters of methanol synthesis catalyst are required, and the methanol production rate per unit volume of the methanol synthesis catalyst is 8.66 mol [methanol]/(h·L [catalyst]).

Figure 4 is a process flow diagram of a configuration in which the reverse shift reaction section 1 and the water separation section 2 are omitted from the configuration of Figure 3, and is a comparative example to Figure 3.

The raw gas is introduced directly into the methanol synthesis section 3 at a temperature of 25°C and a flow rate of 1 mol/s of carbon dioxide and 3.778 mol/s of hydrogen. In the methanol synthesis section 3, the gas containing the raw materials carbon dioxide and hydrogen is heated to 150°C by heat exchange with the gas after the methanol synthesis reaction described later in the heat exchanger 431, and further heated to 250°C by heat exchange with the recycled gas after the methanation reaction described later in the heat exchanger 432, and then passed to the methanol synthesis reactor 433 to synthesize methanol from the synthesis gas. The methanol synthesis reactor 433 is a heat exchange type reactor, and the reaction proceeds while maintaining approximately 250°C while removing the heat generated by the methanol synthesis reaction, and the methanol synthesis reaction proceeds to an equilibrium composition of 250°C. The heat is recovered as high-pressure steam. The gas after the methanol synthesis reaction is heat recovered to 150°C in the heat exchanger 434 (the high-temperature side of the heat exchanger 431) and sent to the methanol separation section 4.

In the methanol separation section 4, the gas after the methanol synthesis reaction is cooled to 40°C using cooling water in a heat exchanger 441, and further cooled to below room temperature using a refrigerator and a heat exchanger (not shown), and the produced methanol is separated in a gas-liquid separation drum 442.

In the methanation reaction section 5, the synthesis gas from which methanol has been separated in the methanol separation section 4 is mixed with the gas branched from the outlet of the heat exchanger 452 described later, and is passed through the methanation reactor 451 at 250 ° C to carry out the methanation reaction of the synthesis gas. The methanation reactor 451 is an adiabatic reactor, and the temperature rises as the methanation proceeds, and the methanation reaction proceeds to an equilibrium composition of 579 ° C. In the heat exchanger 452, the gas is cooled to 489 ° C while recovering heat as high-pressure steam, and 72.3% is returned to the inlet side as recycled gas using a recycle compressor (not shown). The recycled gas is first cooled to 433 ° C by heat exchange with the gas on the inlet side of the methanol synthesis catalyst in the heat exchanger 453 (the high-temperature side of the heat exchanger 432), and then cooled to 350 ° C while recovering heat as high-pressure steam in the heat exchanger 354, and mixed with the synthesis gas from which methanol has been separated. The remaining 27.7% is passed through a heat exchanger 455, where it is cooled to 250°C while recovering heat as high-pressure steam, and sent to a methanation reactor 456. The methanation reactor 456 is a heat exchange type reactor in which the reaction proceeds at approximately 250°C while removing the heat generated by the reaction, and the methanation reaction proceeds to an equilibrium composition of 250°C, and the heat is recovered as high-pressure steam. The gas after the reaction is cooled to 150°C by a heat exchanger 457 to obtain low-pressure steam, and is further cooled with cooling water by a heat exchanger 458, and the water is separated in a gas-liquid separation drum 459 to obtain a gas that is mainly composed of methane.

The temperatures and flow rates at key points in the process are shown in Table 2.

The production rates of methanol and methane were 0.222 mol/s and 0.774 mol/s, respectively. The ratio of the calorific value of the product (methanol and methane) to the calorific value of the raw hydrogen was 78.7%. The composition of the main methane gas produced after dehydration was 97.52% methane, 1.98% hydrogen, and 0.50% carbon dioxide. As shown in Table 2, the inlet gas flow rate of the methanol synthesis catalyst was 4.778 mol/s. When the designed catalyst amount of the methanol synthesis catalyst is designed at a gas hourly space velocity (GHSV) of 2000 per hour, 193 liters of methanol synthesis catalyst are required, and the methanol production rate per unit volume of the methanol synthesis catalyst is 4.15 mol [methanol]/(h·L [catalyst]).

Compared to the configuration in Figure 3, the configuration in Figure 4 has a smaller methanol yield per unit volume of the methanol synthesis catalyst, and is clearly less economical as a process for simultaneously producing methanol and methane. In addition, the concentrations of hydrogen and carbon dioxide contained in the main component gas of methane produced by methanation are high, i.e., the purity of methane is low.

Figure 5 is a process flow diagram showing another embodiment of the method and equipment for co-producing methanol and methane according to the present invention.

The raw gas for methanol synthesis is supplied to the reverse shift reaction section 1 at a temperature of 25°C and a flow rate of 1 mol/s of carbon dioxide and 3 mol/s of hydrogen. In the reverse shift reaction section 1, the raw gas is heated to 350°C in the heat exchanger 511 by heat exchange with the gas after the reverse shift reaction described below. Then, the raw gas is passed to the reverse shift reactor 512, where a part of the carbon dioxide is converted to carbon monoxide by the reverse shift reaction. The gas whose temperature has been reduced by the reverse shift reaction is heated to 520°C in the heat exchanger 513 (corresponding to the heat supply section) by heat exchange with the gas after the methanation reaction. Then, the gas is passed to the reverse shift reactor 514, where the reverse shift reaction is further advanced to further increase the proportion of carbon monoxide (reverse shift reaction process). The outlet gas of the reverse shift reactor 514 is cooled to 150°C by heat exchange with the raw gas in the heat exchanger 515 (= the high temperature side of the heat exchanger 511) and sent to the water separation section 2.

In the water separation section 2, the gas after the reverse shift reaction is further cooled to 40°C using cooling water in a heat exchanger 521. The water condensed by cooling is separated from the synthesis gas in a gas-liquid separation drum 522 (water separation process).

In the methanol synthesis section 3, the synthesis gas from which water has been separated in the water separation section 2 is heated to 150°C in the heat exchanger 531 by heat exchange with the gas after the methanol synthesis reaction described later, and further heated to 250°C in the heat exchanger 532 by heat exchange with the recycled gas after the methanation reaction described later, and then passed to the methanol synthesis reactor 533 to synthesize methanol from the synthesis gas. The methanol synthesis reactor 533 is a heat exchange type reactor, and the reaction proceeds while maintaining approximately 250°C while removing the heat generated by the methanol synthesis reaction, and the methanol synthesis reaction proceeds to an equilibrium composition of 250°C (methanol synthesis process). The heat is recovered as high-pressure steam. The gas after the methanol synthesis reaction is heat recovered to 150°C in the heat exchanger 534 (the high-temperature side of the heat exchanger 531) and sent to the methanol separation section 4.

In the methanol separation section 4, the gas after the methanol synthesis reaction is cooled to 40°C using cooling water in a heat exchanger 541, and then cooled to room temperature or below using a refrigerator and a heat exchanger (not shown), and the produced methanol is separated in a gas-liquid separation drum 542 (methanol separation process). 1% by volume of the synthesis gas from which methanol has been separated in the methanol separation section 4 is extracted to the outside of the system as purge gas in a flow rate adjustment section 543, and the remainder is returned to the inlet of the reverse shift reaction section using a recycle compressor (not shown).

The raw gas for the methanation reaction is supplied to the methanation reaction section 5 at a temperature of 25°C and a flow rate of 1 mol/s of carbon dioxide and 4 mol/s of hydrogen. The raw gas is heated to 250°C in the heat exchanger 551 by heat exchange with the gas after the methanation reaction described later, and is further mixed with the gas branched from the outlet of the heat exchanger 556 described later and introduced into the methanation reactor 552 at 250°C. The methanation reactor 552 is an adiabatic reactor, and the temperature rises as the methanation proceeds, and the methanation reaction proceeds to an equilibrium composition of 600°C (methanation reaction process). The heat exchanger 553 is the high-temperature side (heat dissipation side) of the heat exchanger 513, and the gas after the methanation reaction is cooled to 454°C by heat exchange. The next heat exchanger 554 is the high-temperature side (heat dissipation side) of the heat exchanger 532, and the gas after the methanation is further cooled to 385°C by heat exchange. The next heat exchanger 555 is the high temperature side (heat dissipation side) of the heat exchanger 551, and is further cooled to 298°C by heat exchange with the raw material gas. In the next heat exchanger 556, the gas after methanation is cooled to 250°C while recovering heat as high pressure steam. 67.6% of the cooled gas is returned to the inlet side as recycled gas using a recycle compressor (not shown). The remaining 32.4% is sent to the methanation reactor 557. The methanation reactor 557 is a heat exchange type reactor, and the reaction proceeds while maintaining approximately 250°C while removing heat generated by the reaction, and the methanation reaction proceeds to an equilibrium composition of 250°C, and the heat is recovered as high pressure steam. The gas after the reaction is heat recovered to 150°C by the heat exchanger 558 to obtain low pressure steam, and is further cooled with cooling water by the heat exchanger 559, and water is separated in the gas-liquid separation drum 560 to obtain methane-based gas.

The temperature and flow rate at the inlet and outlet of the methanol synthesis reactor 533 are shown in Table 3.

The production rates of methanol and methane were 0.983 mol/s and 0.995 mol/s, respectively. The ratio of the calorific value of the product (methanol and methane) to the calorific value of the raw hydrogen was 79.9%. The composition of the main methane gas produced after dehydration was 97.44% methane, 2.05% hydrogen, and 0.51% carbon dioxide. As shown in Table 3, the inlet gas flow rate of the methanol synthesis catalyst was 9.261 mol/s. When the designed catalyst amount of the methanol synthesis catalyst is designed at a gas hourly space velocity (GHSV) of 2000 per hour, 374 liters of methanol synthesis catalyst are required, and the methanol production rate per unit volume of the methanol synthesis catalyst is 9.48 mol [methanol]/(h·L [catalyst]).

In the configuration of Figure 5, when the purge gas after methanol separation was mixed with the raw material for methanation, the composition of the methane-based gas after dehydration was the same, and the methane production rate increased to 1.011 mol/s. However, it was necessary to adjust the flow rate of the raw gas for the methanation reaction to 4.017 mol/s. Under these conditions, the ratio of the calorific value of the products (methanol and methane) to the calorific value of the raw hydrogen increased to 80.5%. This is because the purge gas was used as the raw material for methanation.

Figure 6 is a process flow diagram of a configuration in which the reverse shift reaction section 1 and the water separation section 2 are omitted from the configuration of Figure 5, and is a comparative example to Figure 5.

The raw material gas for methanol synthesis is supplied to the methanol synthesis section 3 at a temperature of 25° C. and at flow rates of carbon dioxide 1 mol/s and hydrogen 3 mol/s.
In the methanol synthesis section 3, the gas is heated to 150°C by heat exchange with the gas after the methanol synthesis reaction described later in the heat exchanger 631, and further heated to 250°C by heat exchange with the recycled gas after the methanation reaction described later in the heat exchanger 632, and then passed to the methanol synthesis reactor 633 to synthesize methanol from the synthesis gas. The methanol synthesis reactor 633 is a heat exchange type reactor, and the reaction proceeds while maintaining approximately 250°C while removing the heat generated by the methanol synthesis reaction, and the methanol synthesis reaction proceeds to an equilibrium composition of 250°C. The heat is recovered as high-pressure steam. The gas after the methanol synthesis reaction is heat recovered to 150°C in the heat exchanger 634 (the high-temperature side of the heat exchanger 531) and sent to the methanol separation section 4.

In the methanol separation section 4, the gas after the methanol synthesis reaction is cooled to 40°C using cooling water in a heat exchanger 641, and then cooled to room temperature or below using a refrigerator and a heat exchanger (not shown), and the produced methanol is separated in a gas-liquid separation drum 642. Of the synthesis gas from which methanol has been separated in the methanol separation section 4, 1% by volume is extracted to the outside of the system as purge gas in a flow rate adjustment section 643, and the remainder is returned to the inlet of the reverse shift reaction section using a recycle compressor (not shown).

The raw gas for the methanation reaction is supplied to the methanation reaction section 5 at a temperature of 25°C and a flow rate of 1 mol/s of carbon dioxide and 4 mol/s of hydrogen. The raw gas is heated to 250°C in the heat exchanger 651 by heat exchange with the gas after the methanation reaction described later, and is further mixed with the gas branched from the outlet of the heat exchanger 655 described later and introduced into the methanation reactor 652 at 250°C. The methanation reactor 652 is an adiabatic reactor, and the temperature rises as the methanation proceeds, and the methanation reaction proceeds to an equilibrium composition of 600°C. The heat exchanger 653 is the high-temperature side (heat dissipation side) of the heat exchanger 632, and the gas after the methanation reaction is cooled to 470°C by heat exchange. The next heat exchanger 654 is the high-temperature side (heat dissipation side) of the heat exchanger 651, and is further cooled to 386°C by heat exchange with the raw gas. In the next heat exchanger 655, the gas after methanation is cooled to 250°C while recovering heat as high-pressure steam. 67.6% of the cooled gas is returned to the inlet side as recycled gas using a recycle compressor (not shown). The remaining 32.4% is sent to the methanation reactor 656. The methanation reactor 656 is a heat exchange type reactor in which the reaction proceeds while maintaining approximately 250°C while removing the heat generated by the reaction, and the methanation reaction proceeds to an equilibrium composition of 250°C, and the heat is recovered as high-pressure steam. The gas after the reaction is cooled to 150°C by heat exchanger 657 to obtain low-pressure steam, and then further cooled with cooling water by heat exchanger 658, and water is separated in gas-liquid separation drum 659 to obtain methane-based gas.

The temperature and flow rate at the inlet and outlet of the methanol synthesis reactor 633 are shown in Table 4.

The production rates of methanol and methane were 0.964 mol/s and 0.995 mol/s, respectively. The ratio of the calorific value of the product (methanol and methane) to the calorific value of the raw hydrogen was 79.2%. The reason that the ratio was lower than the ratio (79.9%) in the configuration of Figure 5 is thought to be that the single-pass conversion rate in the methanol synthesis process decreased, the proportion of the gas circulated as recycled gas increased, and the amount of purge gas increased. The composition of the generated methane-based gas after dehydration was 97.44% methane, 2.05% hydrogen, and 0.51% carbon dioxide. In addition, as shown in Table 4, the inlet gas volume of the methanol synthesis catalyst was 17.85 mol/s. When the designed catalyst volume of the methanol synthesis catalyst is designed at a gas hourly space velocity (GHSV) of 2000 per hour, 720 liters of methanol synthesis catalyst are required, and the methanol production volume per unit volume of the methanol synthesis catalyst is 4.82 mol [methanol]/(h·L [catalyst]). Compared to the configuration in Figure 5, the amount of methanol produced per unit volume of the methanol synthesis catalyst was halved.

Comparing the single-pass conversion of methanol synthesis from the gas compositions at the inlet and outlet of the methanol synthesis catalyst in Tables 3 and 4, the configuration in Figure 5 shows 38% and the configuration in Figure 6 shows 21%. In the configuration in Figure 5, which includes a reverse shift reaction step, the composition ratio of carbon monoxide and carbon dioxide at the inlet of the methanol synthesis catalyst is approximately 1:1, which is considered to have led to a high single-pass conversion. On the other hand, in the configuration in Figure 6, the composition ratio of carbon monoxide and carbon dioxide at the inlet of the methanol synthesis catalyst is approximately 1:10, which is considered to have led to a low single-pass conversion rate that is almost the same as the equilibrium conversion rate (approximately 20%) when a gas with a CO ₂ :H ₂ = 1:3 ratio is subjected to the methanol synthesis reaction.

The introduction of the reverse shift reaction process significantly improved the single-pass conversion rate in the methanol synthesis process, which resulted in an increase in the amount of methanol produced per unit volume of the methanol synthesis catalyst, a reduction in the amount of unreacted gas recycled, and a reduction in the amount of purge gas. This is believed to have improved the ratio of the calorific value of the products (methanol and methane) to the calorific value of the feed hydrogen.

[Another embodiment]
[1] In the above embodiment, the reaction pressure in the methanol synthesis step and the reaction pressure in the methanation reaction step are the same (5 MPa). However, in the methanol synthesis step and the methanation reaction step according to the present invention, the pressures may be the same or different.

[2] In the embodiment shown in Figs. 1 and 3, no flow rate adjustment unit is provided, and the entire amount of the synthesis gas from which methanol has been separated in the methanol separation unit 4 is supplied to the methanation reaction unit 5, but this is not limited to the above. A flow rate adjustment unit may be provided, and a portion of the synthesis gas from which methanol has been separated in the methanol separation unit 4 may be extracted to the outside of the system as a purge gas, and the remainder may be supplied to the methanation reaction unit 5, or the entire amount of the synthesis gas may be supplied to the methanation reaction unit 5.

[3] In the embodiment shown in FIG. 2, the flow rate adjustment unit 7 is configured to be able to arbitrarily adjust the amount of synthesis gas returned to the reverse shift reaction unit 1 and the amount of synthesis gas supplied to the methanation reaction unit 5, and the synthesis gas after methanol separation in the methanol separation unit 4 passes through the flow rate adjustment unit 7, and most of the synthesis gas is returned to the inlet of the reverse shift reaction unit 1, and the remainder is mixed with a separately prepared raw material gas (hydrogen and carbon dioxide) and used as a raw material for the methanation reaction process, but this is not limited to this. The flow rate adjustment unit 7 may be configured to arbitrarily adjust the amount of synthesis gas returned to the reverse shift reaction unit 1, the amount of synthesis gas supplied to the methanation reaction unit 5, and the amount of synthesis gas discharged outside the system as a purge gas. In this case, for example, a predetermined amount of the synthesis gas after methanol separation may be returned to the inlet of the reverse shift reaction unit 1, a predetermined amount may be supplied to the methanation reaction unit 5, and a predetermined amount may be discharged outside the system as a purge gas.

[4] In the embodiment shown in FIG. 5, a flow rate adjustment unit 543 is provided, and a portion of the synthesis gas from which methanol has been separated in the methanol separation unit 4 is extracted to the outside of the system as a purge gas, and the remainder is returned to the inlet of the reverse shift reaction unit 1. However, this is not limited to this. For example, the entire amount of the synthesis gas from which methanol has been separated may be returned to the inlet of the reverse shift reaction unit 1, or a configuration may be adopted in which no flow rate adjustment unit is provided, and the entire amount of the synthesis gas may be returned to the inlet of the reverse shift reaction unit 1.

The configurations disclosed in the above embodiments (including other embodiments) can be applied in combination with configurations disclosed in other embodiments, provided no contradictions arise. Furthermore, the embodiments disclosed in this specification are merely examples, and the present invention is not limited thereto, and can be modified as appropriate within the scope of the purpose of the present invention.

The present invention can be used, for example, as a method and equipment for producing methane-based gas, which is a raw material for city gas, and methanol, which can be used as a chemical product or liquid fuel.

Reference Signs List 1 Reverse shift reaction section 2 Water separation section 3 Methanol synthesis section 4 Methanol separation section 5 Methanation reaction section 6 Heat supply section 7 Flow rate adjustment section 312, 314, 512, 514 Reverse shift reactor 333, 533 Methanol synthesis reactor 351, 552 Methanation reactor (adiabatic type)
356, 557 Methanation reactor (heat exchange type)

Claims (5)

A process for co-producing methanol and methane from hydrogen and carbon dioxide, comprising the steps of:
(a) obtaining a synthesis gas containing hydrogen, carbon monoxide, carbon dioxide and water vapor from a raw material gas containing hydrogen and carbon dioxide by a reverse shift reaction;
(b) cooling the synthesis gas to separate water;
(c) passing the synthesis gas from which water has been separated through a methanol synthesis catalyst to synthesize methanol;
(d) cooling the gas obtained in step (c) to separate methanol;
(e) passing a raw material gas containing hydrogen and carbon dioxide through a methanation catalyst to synthesize methane;
At least a part of the synthesis gas from which methanol has been separated in the step (d) is used as a raw material gas for the methanation reaction in the step (e);
Step (e) is carried out only after step (d);
A method for co-producing methanol and methane, comprising using the reaction heat generated in step (e) as a heat source for step (a) via a heat exchanger. The method for co-producing methanol and methane according to claim 1, wherein at least a portion of the synthesis gas obtained in step (d) from which methanol has been separated is mixed with the feed gas for the reverse shift reaction in step (a). A facility for co-producing methanol and methane from hydrogen and carbon dioxide, comprising:
a reverse shift reaction section for obtaining a synthesis gas containing hydrogen, carbon monoxide, carbon dioxide and water vapor from a raw material gas containing hydrogen and carbon dioxide by a reverse shift reaction;
a water separation section that cools the synthesis gas and separates water from it;
a methanol synthesis unit that synthesizes methanol by passing the synthesis gas from which water has been separated through a methanol synthesis catalyst;
a methanol separation section for cooling the gas sent from the methanol synthesis section and separating methanol;
a methanation reaction section that synthesizes methane by passing a raw material gas containing hydrogen and carbon dioxide through a methanation catalyst;
a heat supply section that supplies reaction heat generated in the methanation reaction section to the reverse shift reaction section via a heat exchanger;
A methanol and methane co-production facility configured to supply at least a portion of the synthesis gas sent out from the methanol separation section as a raw material gas to the methanation reaction section , the methanation reaction section being disposed only downstream of the methanol separation section . The methanol and methane co-production equipment according to claim 3, further comprising a flow rate adjustment unit that adjusts the flow rate of the synthesis gas supplied from the methanol separation unit to the methanation reaction unit. At least a part of the synthesis gas sent from the methanol separation section is returned to the reverse shift reaction section as a raw material gas,
5. The methanol and methane co-production facility according to claim 4, wherein the flow rate adjusting section adjusts the flow rate of the synthesis gas supplied from the methanol separation section to the reverse shift reaction section.

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