Moving bed methanol aromatization method for co-production of liquefied gas

Abstract

The invention relates to a moving bed methanol aromatization method for coproducing liquefied gas. The method comprises the steps of hydrocarbon synthesis and separation, at least two serially connected reactors are adopted in the hydrocarbon synthesis step, a reaction raw material and a catalyst sequentially flow through the reactors in a countercurrent direction, and most low carbon olefin-containing circulation gas generated in the separation step returns to different feeding positions in the hydrogen synthesis step as quenching gas or raw material supplement gas in the hydrocarbon synthesis step, a small part of the circulation gas is fractioned through a liquefied gas removal tower, and a raw material methanol is used to wash and absorb C1-C4 light components generated in the separation step, returns, is fed and is converted. The method allows methanol to be converted into mixed aromatic hydrocarbons with high added values and liquefied gas to be produced as a byproduct. The method allows step complete utilization of the activity of the catalyst to be carried out, so the method improves the fine control of the reaction process, realizes effective material utilization and heat integration between processing processes, improves the product yield, reduces energy consumption and reduces environmental pollution.

Description

technical field [0001] The invention relates to a methanol-to-hydrocarbon process using a moving bed for co-production of liquefied gas. Background technique [0002] BTX aromatics (Benzene, Toluene, Xylene) are important basic raw materials in petrochemical industry, among which p-xylene (PX) has the greatest demand. With the rapid expansion of domestic PX downstream PTA and polyester production capacity, the supply of PX in the market is seriously insufficient. By 2013, my country's external dependence on p-xylene has reached 55.3%, and the gap between supply and demand has further increased. The PX project produced by the traditional process is difficult to construct, has a high production technology threshold, and requires a large investment, and is more limited by the raw material naphtha resources. At present, the shortage of oil resources in my country and the increase in consumption demand have caused a shortage of raw materials such as naphtha and light diesel oil ...

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Problems solved by technology

[0007] (1) The degree of back-mixing of the catalyst in the fluidized bed is relatively heavy, and excessive local reaction can easily lead to coking; (2) The turbulence in the fluidized bed is severe, the wear is serious, and the expensive catalyst is easily damaged and then runs out, resulting in economical problems. (3) The residence time distribution in the fluidized bed is wide, which easily leads to a wide distribution of products and a decrease in the yield of the target product; (4) Temperature and pressure fluctuations will affect the efficiency of the gas-solid separation system, thereby affecting the subsequent Fractional distillation system; (5) For the reaction system with low coke formation rate, it is difficult to maintain the heat balance of the reaction regeneration system of the fluidized bed

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