Refining method and refining system of p-xylene crude product

Abstract

The invention relates to a refining method and refining system of a p-xylene crude product. The refining method at least comprises the following steps of: (1) conducting first separation on a p-xylenecrude product as separation feed to obtain p-xylene-rich stream and p-xylene-poor stream; (2) repeating the step (1) for n-1 times, each time taking the p-xylene-poor stream obtained by a previous step as the separation feed for first separation respectively, thus obtaining p-xylene-rich stream of corresponding numbers and p-xylene-poor stream of corresponding numbers, wherein the number n represents arbitrary positive integer equal to or above 2; and (3) subjecting two or more of the first to the n-th p-xylene-rich stream jointly to second separation, thus obtaining p-xylene and first separation residue. The refining method has the advantages of increasing the production of p-xylene, etc.

Description

technical field [0001] The present invention relates to a method for refining hydrocarbons, in particular to a method for refining crude p-xylene. The invention also relates to a corresponding refining system. Background technique [0002] P-xylene is a basic organic chemical product, which is mainly obtained through separation of C8 aromatic hydrocarbons in industry. The so-called C8 aromatics generally refer to ethylbenzene or various isomers of xylene, such as p-xylene, m-xylene and ortho-xylene, but more generally refer to a mixture of two or more of these compounds. The physical and chemical properties of these compounds are similar, and Table 1 reflects the boiling point of each compound at normal pressure. As can be seen from Table 1, the difference between the boiling points of p-xylene and ethylbenzene is 2°C, and the difference between the boiling points of p-xylene and m-xylene is about 1°C. To achieve complete and effective separation between each other, a larg...

AI Technical Summary

Problems solved by technology

Second, the adsorption selectivity of the adsorbent to each compound is different, and the limited adsorption space determines that it is difficult to improve the adsorption yield of p-xylene

It can be seen from the strength ranking that although the toluene content is small, it easily occupies the effective adsorption space of the adsorbent and has an adverse effect on the adsorption capacity of the adsorbent.

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