Adsorption crystallization coupling aromatic hydrocarbon production method and system provided with toluene shape-selective disproportionation

Abstract

The invention relates to an adsorption crystallization coupling aromatic hydrocarbon production method and a system provided with toluene shape-selective disproportionation. The method comprises the steps of adsorption, extraction liquid separation, crystallization purification, C8A isomerization, C7 removal, toluene shape-selective disproportionation, raffinate separation and the like. A discharged material of an isomerization unit is directly sent to a simulated moving bed for selective adsorption, and the simulated moving bed is sequentially divided into an adsorption area, a refining area,a desorption area and an isolation area in the relative movement direction of an adsorbent. An extract is extracted from the desorption area, extracting raffinate is extracted from the middle of theadsorption area, auxiliary extracting raffinate is extracted from the bottom of the adsorption area, and part of C9+ heavy aromatics are discharged through fractional separation of the auxiliary extracting raffinate. The system comprises an adsorption concentration unit, a crystallization purification unit, an isomerization unit and a toluene shape-selective disproportionation unit. According to the invention, the total circulation amount of a process stream is obviously reduced, the construction investment and the operation energy consumption of the whole aromatic hydrocarbon combined deviceare reduced, and PX yield is improved.

Description

technical field [0001] The invention relates to aromatics production technology, in particular to an adsorption crystallization coupled aromatics production method provided with toluene shape-selective disproportionation and an adsorption crystallization coupled aromatics production system provided with toluene shape-selective disproportionation using the method, belonging to the chemical technology field. Background technique [0002] Traditional aromatics complexes usually include three units: isomerization, xylene fractionation, and aromatics separation. The process flow forms a 3-unit large cycle among the above 3 units. Due to the large amount of circulation, the construction investment and operating energy consumption of the entire aromatics complex are increased. [0003] At the same time, among the three units of the existing aromatics complex, the core part is the aromatics separation unit. Since the four isomers in C8 aromatics have similar chemical structures and ...

AI Technical Summary

Problems solved by technology

Since the launch of the latest generation of adsorbents by UOP in the United States and AXENS in France in 2011, there has been no further progress in capacity research. According to their respective research results, the adsorption capacity of the adsorbent has also reached the theoretical value, and the adsorption capacity and selectivity Containing each other, it is difficult to improve performance

[0010] 2) Limitation of adsorption separation process

[0013] 3) Energy-saving limitation of adsorption separation

The use and economy of the steam or electricity generated by low-temperature thermal power generation cannot be generalized. Before the large amount of by-product steam cannot be sent to the terminal, it will become a burden on the combined device; low-temperature heat will generate electricity through steam or organic working fluid. On the one hand, the heat utilization efficiency is low, only about 9% to 13% (9 to 13%); on the other hand, the price of electricity in different regions varies greatly, and whether the high equipment investment in the early stage can be recovered as soon as possible needs careful study

Therefore, the way of low temperature heat utilization is limited

[0015] 4) It is not applicable to the high concentration p-xylene of the new process

Separation of energy consumption accounts for a large proportion of electricity, and regional restrictions are strong

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