JPH0246078B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for converting hydrocarbons, and more specifically, the present invention relates to a method for converting hydrocarbons, and more specifically, a method for converting gasoline fractions by using a hydrocarbon with a low aromatic content as a raw material and a crystalline silicate with a specific crystal structure as a catalyst, and reacting in the presence of water. The present invention relates to a method for efficiently producing liquid hydrocarbons rich in . Several methods have been known for producing hydrocarbons with a high aromatic content from hydrocarbons with a low aromatic content, using ZSM-5 and similar crystalline silicates as catalysts. There is. For example, a method for converting hydrocarbons having 5 or more carbon atoms into aromatic compounds using ZSM-5 type zeolite (Japanese Patent Laid-Open No. 49-41322), There is a method of converting it into an aromatic compound using type 5 zeolite (Japanese Patent Application Laid-open No. 49233/1983). However, these conventional methods have the disadvantage that carbonaceous substances tend to precipitate on the catalyst during the conversion reaction process, resulting in significant deactivation of the catalyst, and the resulting products are heavier than gasoline fractions. There was a drawback. Therefore, the present inventor has conducted repeated research to overcome the drawbacks of the above-mentioned prior art, to develop a method in which the deactivation of the catalyst is slow and a product corresponding to a gasoline fraction can be efficiently obtained, and the present invention has been completed. It came to this. In other words, the present invention provides a method for treating raw material hydrocarbons with a low aromatic content and a carbon number of 2 or more in the presence of water.
A process for converting hydrocarbons is provided, which comprises contacting crystalline silicates of the ZSM-5 type to produce liquid hydrocarbons enriched in gasoline fractions. The raw material hydrocarbons in the method of the present invention include:
As mentioned above, hydrocarbons with a low aromatic content and a carbon number of 2 or more are used. There are no particular restrictions on the type of hydrocarbon, and there is no restriction on the aromatic content either, but usually 15% by weight or less is used. Specific examples of this feedstock hydrocarbon include naphtha fractions such as light naphtha and heavy naphtha, especially fractions with a carbon number of 4 or more and a boiling point of 200°C or less, especially a carbon number of 4
The above-mentioned fractions having a boiling point of 140°C or less can be cited as preferred. Further, olefins and paraffins having 2 to 4 carbon atoms can be used alone or in combination, or in combination with the naphtha fraction. Among these, it is preferable to use a mixture of the naphtha fraction and an olefin having 2 to 4 carbon atoms, and in this case, the mixing ratio of the two, that is, the olefin/naphtha fraction = 0.05 to 19 (weight ratio), is particularly preferable. When the ratio is 0.18 to 5.7 (weight ratio), liquid hydrocarbons with significantly higher gasoline fractions are produced than when each is used alone, and a so-called synergistic effect can be produced. In addition, in the method of the present invention, ZSM-5 is used as a catalyst.
It is necessary to use crystalline silicates of the type. This ZSM-5 type crystalline silicate is
It refers to a material whose X-ray diffraction pattern is the same or similar to ZSM-5, and may contain other metals instead of aluminum, or may contain other elements together with aluminum. Specifically, ZSM-5, ZSM-8, ZSM-
11, the crystalline borosilicate described in JP-A No. 53-55500, the crystalline titanosilicate described in JP-A-56-96720, and the crystalline titanosilicate described in JP-A-56-96720;
Examples include the crystalline metallosilicates described in JP-A No. 162419, JP-A-56-22623, and JP-A-56-59619, and all of these can be used as H type or metal-substituted type. In addition, when using this ZSM-5 type crystalline silicate, alumina etc. can also be used together as a binder. The method of the present invention is characterized in that the conversion reaction of the raw material hydrocarbon is carried out in the presence of water. The presence of water in the reaction system suppresses the precipitation of carbonaceous substances, and as a result, the life of the catalyst is significantly extended. Furthermore, the resulting product is richer in gasoline fraction than in the case where no water is present. The amount of water present in the reaction system varies depending on the raw material hydrocarbon, type of catalyst, reaction conditions, etc.
Although it cannot be determined unambiguously, the weight ratio of water/feedstock hydrocarbon is usually 0.01 to 3, preferably 0.1.
It should be ~1.5. In the method of the present invention, as described above, the raw material hydrocarbon is
The reaction is carried out by contacting ZSM-5 type crystalline silicate in the presence of water, and the reaction conditions at this time are usually normal pressure to 50 kg/cm ² G, preferably normal pressure to 20 kg/cm 2 G. ² G, the temperature is 350 to 600°C, preferably 400 to 550°C, and the weight hourly space velocity (WHSV) of the feedstock hydrocarbon is 0.1 to 50 hr ^-1 , preferably 0.5 to
It should be 10hr ^-1 . According to the method of the present invention as described above, hydrocarbons with a low aromatic content, such as naphtha with a low octane number and olefin gas with limited uses, can be
It can be converted extremely efficiently into gasoline with a high octane number and a rich aromatic content. Therefore, the method of the present invention can be widely used in petroleum refining and petrochemical industries, and can be particularly effectively used in the production of high octane gasoline and aromatic compounds. 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 (SiO ₂ 37.6% by weight, Na ₂ O 17.5
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. Next, 1 g of powdered mordenite was added to this mixture, the pH was adjusted to 10.0, and the mixture was placed in an autoclave at 170°C.
Stir at a rotation speed of 200 rpm and under autogenous pressure.
The reaction was allowed to proceed for 20 hours. 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.
It was 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 fired in an H-shape. Furthermore, alumina sol corresponding to 20% by weight of alumina was added as a binder, extrusion molded, dried at 120°C for 3 hours, and then calcined in air at 550°C for 6 hours to obtain a catalyst. (2) Conversion reaction Using the catalyst obtained in (1) above, normal pressure and temperature
A conversion reaction of light naphtha having the composition shown in Table 1, which is a feedstock hydrocarbon, was carried out under conditions of 450°C, a WHSV of the feedstock hydrocarbon of 1.0 hr ^-1 , and a water/feedstock hydrocarbon weight ratio of 1.0. The results are shown in Table 2. Example 2 In Example 1 (2), a conversion reaction was carried out under the same conditions as in Example 1 (2) except that the temperature was 550°C and the water/raw material hydrocarbon weight ratio was 0.5. . The results are shown in Table 2. Comparative Example 1 Conversion was carried out under the same conditions as in Example 1 (2), except that water was not added to the reaction system, that is, the water/raw material hydrocarbon weight ratio was set to 0. The reaction was carried out. The results are shown in Table 2. Comparative Example 2 In Example 2, a conversion reaction was carried out under the same conditions as in Example 2, except that water was not added to the reaction system, that is, the weight ratio of water/raw material hydrocarbon was set to 0. The results are shown in Table 2.

【table】

[Table] 〓Supplied light naphtha〓
*2 Ratio of C ₅ to C ₅ ⁺ fraction of boiling point 218°C fraction Example 3 Using the catalyst obtained in Example 1 (1), normal pressure and temperature
A conversion reaction of the olefin-containing gas having the composition shown in Table 3, which is the feedstock hydrocarbon, was carried out under the conditions of 400° C., a WHSV of the feedstock hydrocarbon of 0.8 hr ^-1 , and a water/feedstock hydrocarbon weight ratio of 0.8. The results are shown in Table 4. Comparative Example 3 In Example 3, a conversion reaction was carried out under the same conditions as in Example 3, except that water was not added to the reaction system, that is, the weight ratio of water/raw material hydrocarbon was set to 0. The results are shown in Table 4.

【table】

【table】

[Table] *1, *2 Same as Table 2.

Claims (1)

[Claims] 1. A raw material hydrocarbon having a low aromatic content and a carbon number of 2 or more is brought into contact with ZSM-5 type crystalline silicate in the presence of water to produce a liquid hydrocarbon rich in gasoline fraction. A method for converting hydrocarbons, characterized in that: 2. The conversion method according to claim 1, wherein the water/raw material hydrocarbon weight ratio present in the reaction system is 0.01 to 3.