Method for production of o-xylene from coal based raw materials

A technology of o-xylene and p-xylene, which is applied in the field of production of o-xylene (OX), can solve the problems of high cost and low selectivity of o-xylene, and achieve delayed coking and carbon deposition, high activity and xylene selectivity , the effect of good reaction stability

Active Publication Date: 2017-10-20
TONGJI UNIV
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Problems solved by technology

In short, in the existing alkylation reaction or process of methanol and petroleum benzene, the products are toluene, mixed xylenes, light hydrocarbons and a certain amount of heavy aromatics, and the selectivity of o-xylene is very low; and the raw material benzene still depends on the petroleum route obtain, the cost is higher

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  • Method for production of o-xylene from coal based raw materials
  • Method for production of o-xylene from coal based raw materials
  • Method for production of o-xylene from coal based raw materials

Examples

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Embodiment 1

[0030] figure 1 Shown is a typical process flow of the method for producing o-xylene from coal-based raw materials in the present invention. Using crude methanol (89.0%) produced from coal synthesis gas and coked crude benzene (containing 90.4 wt% benzene, 8.0 wt% toluene, 1.5 wt% xylene and 0.1 wt% other impurities) as raw materials, the coked crude benzene was washed with sulfuric acid , hydrogenation pretreatment (NiO-MoO 3 and Co-MoO 3 Catalyst, fixed bed), and the crude methanol enters the alkylation reactor (fluidized bed) for catalytic reaction, and the obtained products are mainly toluene, mixed xylenes, trimethylbenzenes, a small amount of heavy aromatics and light hydrocarbons. The above products enter the rectification system together, and first pass through the stripping tower to separate light hydrocarbons as fuel for the device; the heavy components flowing out of the stripping tower pass through the benzene tower to separate and obtain unconverted benzene, whi...

Embodiment 2

[0033] This embodiment ( figure 2 ) differs from Example 1 in that: 1) the raw material of coal-based methanol is crude methanol (methanol content 93.0 wt%) produced by coal coke oven gas; 2) the process system is introduced into a toluene disproportionation reactor (fixed bed), namely Part of the separated toluene enters the toluene disproportionation reactor, and the reaction products (benzene and mixed xylenes) together with unconverted toluene enter the outlet material of the alkylation reactor and enter the rectification system together; the catalyst used for the disproportionation reaction is 2.0% Co and 5.0%B 2 o 3 Co-modified EU-1 molecular sieves, the disproportionation reaction conditions are: the reaction pressure is normal pressure, the reaction temperature is 700 ℃, and the total mass space velocity is 5.0 h -1 ; using H 2 For the reaction carrier gas, the molar ratio of carrier gas to raw material is 5:1. 3) The alkylation reactor adopts a fixed bed reactor. ...

Embodiment 3

[0035] This embodiment ( image 3 ) differs from Example 1 in that: 1) The raw material of coal-based benzene is crude benzene obtained by lightening heavy components of coal tar, containing 79.8 wt% benzene, 15.0 wt% toluene, 5.0 wt% xylene and 0.2 wt% other impurities ; 2) Alkylation reactor adopts moving bed reactor. 3) The catalyst used in the alkylation reaction is a sheet-like MCM-56 / sheet-like MCM-49 composite molecular sieve modified with 2.0%MgO and 8.0%CaO, with an external specific surface area of ​​92 m 2 / g, the number of acid sites on the outer surface accounted for 31% of the total acid sites, and the number of weak acid and medium strong acid sites accounted for 98.1% of the total acid sites. The alkylation reaction conditions are: the molar ratio of methanol to aromatics (benzene and toluene) is 1:2, the reaction pressure is 5.0 MPa, the reaction temperature is 700 °C, the molar ratio of water to raw materials is 10:1, and the total mass space velocity is 0....

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Abstract

The invention relates to a method for production of o-xylene from coal based raw materials. The method adopts cheap coal based crude benzene and coal based crude methanol as the raw materials, employs a weak acid and medium strong acid based alkylation catalyst with large surface area and an anti-coking alkylation reaction medium, and carries out pickling, hydropretreating, alkylation reaction, rectification, isomerization reaction, and transalkylation reaction for high selectivity production of o-xylene; optionally, the method further comprises toluene disproportionation reaction. The alkylation reaction is carried out in a fixed bed, fluidized bed or moving bed reactor, the catalyst is a two-metal oxide modified flake MCM-56, nano acicular ZSM-5, flake MCM-49 or nano Beta molecular sieve, or a compound thereof; the isomerization, transalkylation and disproportionation reactions also use the novel special catalyst, and are all carried out in a fixed bed reactor. The method provided by the invention can effectively reduce the production cost of o-xylene, and completely realizes non-petroleum route production thereof.

Description

technical field [0001] The invention relates to a method for producing o-xylene (OX) from coal-based raw materials. The method uses cheap coal-based crude benzene and coal-based methanol as raw materials, adopts a new type of alkylation catalyst with a large external specific surface area, weak acid and medium strong acid, and an anti-coking alkylation reaction medium. Processes such as hydrogen pretreatment, alkylation reaction, rectification, isomerization reaction, transalkylation and material circulation, realize the production of o-xylene with high selectivity and low cost; optionally, the method further includes toluene disproportionation reaction. The method can thoroughly realize the high-efficiency production of o-xylene through a non-petroleum route. Background technique [0002] As an important basic aromatic raw material, o-xylene (OX) is mainly used in the production of phthalic anhydride, dyes, pesticides, drugs, etc., and can also be used as an aviation gaso...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C2/86C07C5/27C07C15/08
CPCC07C2/864C07C5/2737C07C15/08Y02P20/52
Inventor 朱志荣李军辉吴祥胡超郝志显
Owner TONGJI UNIV
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