JPH0246077B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for converting gaseous hydrocarbons, and more particularly, gaseous hydrocarbons having 2 to 4 carbon atoms, including paraffinic hydrocarbons and olefinic hydrocarbons, are used as raw materials, and this is converted into a relatively low-temperature first stage and a high-temperature stage. A catalytic conversion reaction is carried out in the second stage of
This invention relates to a method for efficiently obtaining liquid hydrocarbons such as gasoline with a high octane number. In general, the butane-butene fraction (BB fraction) produced from fluidized bed catalytic cracking (FCC) contains approximately 50% olefin content, making it unsuitable for commercial use as a fuel. However, it is consumed exclusively as in-house fuel at refineries and other facilities. Therefore, various efforts have been made to convert the BB fraction from FCC into hydrocarbons suitable for commercial fuel. For example, a method has been developed to convert this BB fraction into liquid hydrocarbons rich in aromatics in one step. However, in the one-stage reaction as described above, since the reaction is carried out under conditions that allow a large amount of aromatic components to be obtained, there is a drawback that a large amount of light hydrocarbons are produced as by-products. The present inventor has conducted extensive research in order to overcome the drawbacks of the conventional methods described above and to develop a method for efficiently producing liquid hydrocarbons with a small amount of light gas by-product and a high octane number. As a result, it was discovered that the purpose could be achieved by carrying out the conversion reaction in two stages, by carrying out the reaction at a relatively low temperature in the first stage, and at a slightly high temperature in the second stage, and developed the present invention. completed. That is, the present invention uses gaseous hydrocarbons having 2 to 4 carbon atoms, including paraffinic hydrocarbons and olefinic hydrocarbons, as a raw material, and uses a crystalline silicate catalyst to conduct the first stage contact at a temperature of 100 to 400°C. After carrying out a conversion reaction and then separating the first stage reaction product into liquid hydrocarbon and gaseous hydrocarbon, the gaseous hydrocarbon is used as a raw material and a crystalline silicate catalyst is used at a temperature of 400 to 700°C. The present invention provides a method for converting gaseous hydrocarbons, which is characterized by carrying out a second-stage catalytic conversion reaction. The raw material hydrocarbon in the method of the present invention is a gaseous hydrocarbon having 2 to 4 carbon atoms as described above, and the BB fraction produced from FCC is usually used. This raw material hydrocarbon is mainly composed of gaseous hydrocarbons having 2 to 4 carbon atoms, including paraffinic hydrocarbons and olefinic hydrocarbons, and preferably contains less than 75% by weight of paraffinic hydrocarbons. , and 75% by weight of olefinic hydrocarbons.
A smaller range of mixed compositions can be mentioned. In the method of the present invention, the first stage catalytic conversion reaction is first performed using the gaseous hydrocarbon having 2 to 4 carbon atoms as a raw material. The reaction temperature at this time is 100 to 400
℃, preferably 250-350℃. If the temperature exceeds 400°C in this first stage reaction, the amount of gaseous hydrocarbons such as methane and ethane produced will increase, which is undesirable. On the other hand, when the conversion reaction is carried out in the range of 100 to 400°C, the olefin component in the raw gaseous hydrocarbon reacts preferentially, with almost no by-products of methane, ethane, and ethylene.
Gasoline with a high octane number containing a large amount of olefinic hydrocarbons can be obtained in high yield. In addition, other conditions for the first stage catalytic conversion reaction in the method of the present invention are not particularly limited and may be appropriately selected depending on the type of catalyst used, the type of raw material hydrocarbon, etc., but usually the pressure is kept constant. Pressure~50Kg/
^cm2G , preferably normal pressure to 20Kg/ ^cm2G , and weight hourly space velocity (WHSV) 0.1 to 50hr ^-1 , preferably 0.5 to
It should be 10hr ^-1 . Furthermore, hydrogen can be supplied to the reaction system if desired in order to prevent catalyst deterioration. The amount of hydrogen supplied is not particularly limited and may be determined as appropriate, but the molar ratio of hydrogen/raw material hydrocarbon is generally 0.1 to 6, preferably 1 to 5. Furthermore, it is necessary to use a crystalline silicate as a catalyst in the first stage catalytic conversion reaction of the method of the present invention. Various types of crystalline silicates can be used here, and they may be appropriately selected and used depending on each condition. Specific examples of crystalline silicates include X-type zeolite, Y-type zeolite, A-type zeolite, L-type zeolite,
There are ZSM type zeolites and zeolites similar to these, and there are also zeolites that have been exchanged with hydrogen ions and various metal ions. Of these, especially the ZSM type, especially the ZSM-
Zeolite having a crystal structure of Type 5 or similar thereto is preferred. This ZSM type zeolite and similar zeolites can be roughly divided into silica-alumina type, silica-alumina-active metal type, and silica-active metal type, and the former two in particular have a silica/alumina ratio of 12 to 3000. Preferably. Specific examples of the crystalline silicate that can be used in the method of the present invention are as follows. Silica, alkali metals, periodic table A,
Using one or more metals belonging to groups A, A, B, B, B, B, and water as raw materials, a heterocyclic compound such as morpholine or oxazolidine, ethanolamine,
amino alcohols such as propanolamine,
Add amino acids such as alanine and serine or amides such as acetamide and heat at 80 to 300℃.
Crystalline zeolite obtained by reacting until a sufficient amount of crystalline zeolite is produced in
Publication No. 7817). Crystalline aluminosilicate zeolite obtained by adding alumina to the above raw materials and reacting the same with a crystallizing agent (Japanese Patent Application Laid-open No. 7818/1983). Using silica, alumina, alkali metal and water as raw materials, crystalline zeolite powder is added as a seed crystal and the pH of the reaction system is adjusted to 9-12.
A crystalline aluminosilicate zeolite (Japanese Unexamined Patent Publication No. 7819/1983) obtained by reacting at 80 to 300°C until sufficient crystal formation. Crystals obtained by using silica, alumina, alkali metals, and water as raw materials, adding a heterocyclic compound such as morpholine or oxazolidine as a crystallizing agent, and reacting at 80 to 300°C until sufficient crystal formation. aluminosilicate zeolite (Japanese Unexamined Patent Publication No. 7816/1983). Expressed in molar ratio of oxide (dehydrated form), (0.1 to 2.0) R ₂ /nO・[aM ₂ O ₃・bAl ₂ O ₃ ]・ySiO ₂ (In the above formula, R: one or more types monovalent or divalent cation, a: valence of R, M: one or more trivalent transition metal cations, a+b=
1, has a chemical composition of a≧0, b≧0, y≧12) and further contains alcohols, organic amines, ethers, ketones, esters, and/or organic sulfur compounds or derivatives thereof. Crystalline transition metal organosilicate (Unexamined Japanese Patent Publication No. 1983-
Publication No. 10684). (a) a crystalline aluminosilicate zeolite having a uniform pore size in the range of about 6 to 15 Å and a silica to alumina molar ratio of at least about 3; (b) an inorganic oxide matrix; and (c) a catalyst comprising discrete alumina particles. and the zeolite is
(b) has a unit cell size of about 24.5 Å or more before being composited with component, contains an alkali metal to such an extent that the weight ratio of alkali metal oxide/the zeolite is 0.024 or less, and contains rare earth metal oxide. A crystalline zeolite-based catalyst containing a rare earth metal such that the weight ratio of substance/zeolite is about 0.01 to 0.08 (Japanese Unexamined Patent Publication No. 57-91741). It has a specific X-ray diffraction pattern and the molar ratio of oxides is 0.9±0.2M ₂ /nO:W ₂ O ₃ :bYO ₂ :zH ₂ O (where M is a cation and n is the cation). ion valence, W is aluminum or gallium, Y is silicon or germanium, and z is 0 to 40, b is at least 5, preferably 15 to 300), or 0.9±0.2M ₂ / _nO : _Al2O3 : _15-300SiO2 : _zH2O (wherein M is an alkali metal cation, in particular a sodium and tetraalkylammonium cation (the alkyl group preferably contains 2 to 5 carbon atoms) ), where n and z are the same as above.)
ZSM-5 series zeolite as expressed by . It has a specific X-ray diffraction pattern and the molar ratio of oxides is 0.9±0.2M2 _/ nO: _{Al2O3 :} 15-300SiO2 _{: zH2O} (where M is at least one cation (where n is its valence and z is 0 to 40) or 0.9±0.2M ₂ /nO: Al ₂ O ₃ : 15 to 60 SiO ₂ : zH ₂ O (where M is an alkali metal positive Zeolites of the ZSM-8 series, such as those selected from the group consisting of ions, in particular sodium ions and mixtures of tetraethylammonium cations. It has a specific X-ray diffraction pattern and the molar ratio of oxides is 0.9±0.3M2 _/ nO: _{Al2O3 :} 20~90SiO2 _{: zH2O} (wherein M is at least one cationic ion, n
is its valence, and z is from 6 to 12. ) or 0.9±0.3M ₂ /nO: Al ₂ O ₃ : 20~
90SiO ₂ :zH ₂ O (wherein M is selected from the group consisting of a mixture of alkali metal cations, particularly sodium ions and tetrabutylammonium cations) -52104). (a) has a specific X-ray diffraction pattern; (b) converts the silicate into the H-form at 400°C at 2 x 10 ^-9 bar;
When measured at a hydrocarbon pressure of 8 x 10 ^-2 bar and 100 °C after vacuum treatment for 16 hours at and the ratio of n-hexane absorption rate/2,2-dimethylbutane absorption rate is at least 1.5, and (c) the composition expressed in moles of oxide has the formula (1.0±0.3) _M2 /
It is represented by nO・y・Al ₂ O ₃・SiO ₂ (in the formula, M is hydrogen, an alkali metal or an alkaline earth metal, n is the valence of M, and 0<y≦0.01), (d) A crystalline silicate in which the average size of microcrystals is 500 nm or less (JP-A-55-124721, JP-A-55-125195). a silica/alumina molar ratio of at least 12;
Crystalline zeolites with control index of 1 to 12 (ZSM-5, ZSM-11, ZSM-12, ZSM-23,
ZSM-35, ZSM-38, ZSM-48 and similar substances), which can be formed on the zeolite by treating the zeolite with one or more compounds containing metal elements of group A of the periodic table. A crystalline zeolite obtained by precipitating at least 0.5% by weight of the above elements (Japanese Patent Laid-Open No. 57-95922). In addition to the above-mentioned crystalline silicates, various other materials can be used in the method of the present invention, and the method is not limited thereto. Further, the particle size of the crystalline silicate used as a catalyst is not particularly limited, but is generally 0.005 to 30 microns. Although this crystalline silicate may be used as it is, it is handled better if it is mixed with alumina etc. as a binder and extruded into an appropriate shape such as a cube, round, sphere, cylinder or star. is convenient and preferable. In the method of the present invention, after the first stage catalytic conversion reaction is completed, the obtained reaction product is separated into liquid hydrocarbons and gaseous hydrocarbons. The separated liquid hydrocarbons contain a large amount of high octane gasoline fraction, while the gaseous hydrocarbons consist mostly of paraffins, such as methane, ethane, propane, butane, etc. In the method of the present invention, the second stage catalytic conversion reaction is carried out using the above gaseous hydrocarbon as a raw material. The reaction temperature at this time is 400~700℃, preferably 450~
The temperature is 550°C, which should be higher than the first stage conversion reaction described above. Here, at temperatures below 400℃, there is little conversion to liquid hydrocarbons, and conversely, at temperatures below 700℃
Exceeding this will cause severe deterioration of the catalyst and increase operating costs, making it impractical. In contrast, 400-700℃
When the second stage catalytic conversion reaction is carried out in the range of 0.05 to 0.05%, liquid hydrocarbons rich in aromatic components can be obtained in high yield. Further, other conditions for the second stage catalytic conversion reaction in the method of the present invention are not particularly limited and may be appropriately selected depending on the type of catalyst used, the composition of the gaseous hydrocarbon to be supplied, etc., but usually, The pressure is normal pressure ~ 50Kg/cm ² G, preferably normal pressure ~ 20Kg/cm ² G, and WHSV 0.1 ~ 50hr ^-1 , preferably 0.5 ~ 10hr ^-1
Should be. Furthermore, hydrogen can be added to the reaction system if desired in order to prevent catalyst deterioration, as in the case of the first stage catalytic conversion reaction described above. The amount of hydrogen supplied at this time is not particularly limited and may be determined as appropriate, but it is generally 0.1 to 6 (molar ratio), preferably 1 to 5 (molar ratio) relative to the introduced gaseous hydrocarbon. Further, although this hydrogen may be newly supplied, the hydrogen supplied to the first stage reaction may be used as is. Furthermore, in the second stage catalytic conversion reaction of the method of the present invention, it is necessary to use a crystalline silicate as a catalyst. This crystalline silicate may be the same as or different from the crystalline silicate used in the first stage catalytic conversion reaction. Specifically, those mentioned above are preferably used. According to this second-stage catalytic conversion reaction, liquid hydrocarbons rich in aromatic components can be efficiently obtained. Further, the gaseous hydrocarbons produced as a by-product here can be separated and then recycled to the first or second stage reaction system. As described above, according to the method of the present invention, liquid hydrocarbons with a high octane number can be obtained in high yield from gaseous hydrocarbons having a carbon number of 2 to 4, which have low utility value, and methane gas with low reactivity can be obtained. By-products can be suppressed. Therefore, the method of the present invention can be effectively used industrially as a method for efficiently producing high octane gasoline. Next, the present invention will be explained in more detail with reference to Examples. Example 1 (1) Preparation of catalyst A solution () consisting of 7.52 g of aluminum sulfate (18 hydrate), 17.6 g of sulfuric acid (97%) and 250 ml of water, water glass (37.6% by weight of SiO ₂ , 17.5% of Na ₂ O)
A solution (2) consisting of 162 g (wt%, 44.9 wt% water) and 300 ml of water, and a solution (2) consisting of 79 g of sodium chloride and 122 ml of water were prepared, respectively. Next, solution () and solution () were simultaneously gradually dropped into the above solution () while stirring at room temperature to obtain a mixture. Subsequently, 1 g of powdered mordenite was added to this mixture, the pH was adjusted to 10.0, and the mixture was placed in a 1-volume autoclave and heated to 170 ml.
The mixture was stirred at a rotational speed of 200 rpm at ℃, and reacted for 20 hours under autogenous pressure. The reaction mixture was then cooled and washed five times with 1 portion of water. The solid content was then separated by filtration and dried at 120° C. for 3 hours, yielding 40.5 g of crystalline aluminosilicate zeolite. This crystalline aluminosilicate zeolite was confirmed by X-ray diffraction and was found to be ZSM-5. Note that this ZSM-5 has the following composition in terms of molar ratio. 0.9Na ₂ O・60SiO ₂・1.0Al ₂ O ₃ ZSM-5 obtained by the above method was ion-exchanged twice with 5 ml of 1N ammonium nitrate per 1 g, dried at 120°C, and then exposed to air at 550°C for 6 hours. It was combusted inside and became H type. Furthermore, this H type
Add 20% by weight of alumina as a binder to ZSM-5, mix, extrude, and heat to 120°C.
Dry for 3 hours, then dry in air at 550℃ for 6 hours.
After firing for a period of time, cylindrical catalyst particles having a diameter of 1 mm and a length of 5 to 6 mm were obtained. (2) Conversion reaction A stainless steel reaction tube was filled with the catalyst obtained in (1) above, and a gaseous hydrocarbon having the composition shown in Table 1 was passed through it to perform the first stage conversion under specified conditions. The reaction was carried out. Subsequently, the product obtained in the above conversion reaction is separated into gas and liquid, and the generated gaseous hydrocarbon is passed through a stainless steel reaction tube as a raw material to perform a second stage conversion reaction under predetermined conditions. Ta. The results are shown in Table 2. Example 2 (1) Preparation of catalyst The crystalline silicate obtained in Example 1 (1) (ion-exchanged twice with ammonium nitrate and dried) was treated twice with 10 ml/g of 0.5N zinc nitrate. Ion exchanged. Furthermore, after thoroughly washing with ion-exchanged water and filtering, dry at 120℃.
Subsequently, it was calcined in air at 550°C for 6 hours to obtain a zinc-exchanged ZSM-5 catalyst. (2) Conversion reaction Using the catalyst obtained in Example 1 (1), Example 1
The first stage conversion reaction was carried out in the same manner as in (2). Subsequently, after gas-liquid separation of the product, the second stage was carried out in the same manner as in Example 1 (2) using the obtained gaseous hydrocarbon as a raw material and the catalyst obtained in Example 2 (1). A conversion reaction was carried out. The results are shown in Table 2.

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Claims (1)

[Claims] 1 Using gaseous hydrocarbons having 2 to 4 carbon atoms, including paraffinic hydrocarbons and olefinic hydrocarbons, as raw materials, using a crystalline silicate catalyst,
The first stage catalytic conversion reaction is carried out at 100 to 400°C, and then the first stage reaction product is separated into liquid hydrocarbon and gaseous hydrocarbon, and then the gaseous hydrocarbon is used as a raw material to convert crystalline A method for converting hydrocarbons, characterized by carrying out a second stage catalytic conversion reaction at a temperature of 400 to 700°C using a silicate catalyst.