Fine purification system and method for carbonization crude benzol

Abstract

The present invention relates to a refining system of coked crude benzole and a refining method thereof. The basic equipment consists of two benzene towers, a primary tower, a first pure benzene tower, a second pure benzene tower, a toluene tower and a xylene tower. The heat of the reboiler of the primary tower comes from toluene vapor on the top of the toluene tower; the heat of the reboiler of the first pure benzene tower comes from the pure benzene vapor on the top of the second pure benzene tower. The refining method comprises pre-distillation, refining of the pure benzene and separation of the toluene and the xylene. The method not only saves energy but also reduces the cost of investment. The process is simplified. Compared with the traditional sulfuric acid washing process, the method eliminates the acid-alkali washing and benzene blowing processes. The whole process generates no waste acid, acid residue, caustic dross or waste water, which can cause serious damage to the environment. Compared with the catalytic hydrogenation, the method has the advantages of simplifying the process, lowering the energy consumption, reducing the cost of investment and production, and improving the benefit of production, and thus being an excellent method for steel enterprises and coking enterprises to further process and make use of by-products.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a refining system of coking crude benzene and a refining method thereof. Background technique [0002] Benzene, toluene and xylene are all important basic organic chemical raw materials and occupy an extremely important position in the chemical industry. They are mainly derived from petroleum processing, and are referred to as petroleum benzene for short. Crude benzene is a by-product of the coal coking industry, referred to as coking crude benzene, and its composition is complex. As the main components, benzene, toluene and xylene account for more than 90% of the total crude benzene. Due to the shortage of petroleum benzene in the global market, the price has remained high, making coking crude benzene an important source of benzene-based products, and effectively making up for the shortage of benzene-based products in the market. [0003] At present, there are two m...

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Problems solved by technology

[0006] Although the hydrogenation process can obtain high-quality benzene-based products, its disadvantages are complex process technology, large equipment investment, and high energy consumption. In addition, there is an unavoidable defect in the above-mentioned crude benzene hydrogenation refining process, that is, there is Some aromatics are hydrogenated into naphthenes or alkanes, resulting in large loss of aromatics and low yield of aromatics products

[0007] The structural defect of existing coking crude benzene refining equipment is that each tower in the whole separation system is equipped with facilities such as tower bottom heating and tower top condensation, so a large amount of heat energy and circulating cooling water are consumed

Some processes (such as German patent 4586986) adopt pressurized operation in the preheating rectification tower, and then use the high-temperature steam at the top of the tower as the heat source of other towers. Although this can save energy, due to the high operating pressure of the pre-rectification tower , the temperature is high, which leads to a substantial increase in equipment investment, and requires a high-temperature heat source, which requires a substantial increase in investment in the construction of a high-temperature heat carrier system, so the production cost is still high

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