A method for increasing production of low-carbon olefins and aromatics by steam cracking of coker gasoline

Abstract

The invention relates to a method for increasing yields of low-carbon olefins and aromatics by coker gasoline steam cracking, which comprises the following steps: raw oil and hydrogen are mixed and introduced into a hydropretreating procedure to remove olefins and nitrogen impurities, thereby obtaining a hydrogenated coker gasoline stream; the hydrogenated coker gasoline stream is introduced into an aromatic extraction procedure to perform conventional solvent extraction separation or ionic liquid solvent extraction separation, thereby obtaining an aromatic-deficient stream and an aromatic-rich crude aromatic stream; the aromatic-deficient stream enters a steam cracking procedure to be subjected to cracking and separation; the crude aromatic stream is sent into a hydrocracked gasoline aromatic extraction unit to separate the aromatic product; and the obtained stream containing rich saturated hydrocarbons is returned and introduced into the cracking procedure together with the aromatic-deficient petroleum hydrocarbon stream to react and produce the low-carbon olefins. The method provides a proper application way for coker gasoline, widens the cracking raw material sources, recycles the non-aromatic components by using the original cracking hydrogasoline aromatic extraction system, and increases the yields of the low-carbon olefins and aromatics in the cracking process.

Description

technical field [0001] The invention relates to a method for increasing the production of low-carbon olefins and aromatics, more specifically, the invention relates to a method for increasing the production of low-carbon olefins and aromatics by steam cracking after coking gasoline is hydrofined and aromatics extracted. technical background [0002] Low-carbon olefins such as ethylene and propylene are the basic raw materials for chemical production, and steam cracking equipment is the leader of petrochemical industry, which has a major impact on the economic benefits of enterprises. The current steam cracking raw materials are mainly four kinds of naphtha, hydrogenated tail oil, light hydrocarbon and diesel oil. In recent years, with the continuous increase of ethylene production capacity and the increasing shortage of crude oil resources, the contradiction between the supply and demand of ethylene raw materials has gradually increased, and how to expand its raw material so...

AI Technical Summary

Problems solved by technology

However, the content of olefins and nitrogen in coking gasoline is relatively high, which will lead to an increase in the amount of coking in the cracking furnace and the accumulation of nitrogen in the low-temperature zone of the ethylene separation cold box, resulting in explosion accidents. Therefore, some people have proposed to convert coking gasoline into chemical light oil after hydrogenation. , used as raw material for ethylene industry

However, the content of aromatic hydrocarbons in hydrocoking gasoline is still relatively high, and only the side chains of aromatic hydrocarbons in the cracking raw materials can be cracked to produce target products such as ethylene or propylene. The bond energy of the aromatic ring itself is as high as 611KJ / mol due to the C—C conjugated bond. It is difficult to open the ring, and coking precursors are formed at 500-900°C. With the catalytic effect of the nickel alloy steel of the furnace tube material, dehydrogenation and polycondensation can be performed at 300-400°C to form asphaltenes with poor fluidity, which is serious affect production

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