Backwashing method of simulated moving bed device for adsorbing and separating xylene

Abstract

The invention discloses a backwashing method of a simulated moving bed device for adsorbing and separating xylene. Two adjacent inlet and outlet pipelines of the simulated moving bed device are used as a group of cleaning pipes, the inlet and outlet pipeline positioned on the downstream side of a material path is used as a washing liquid inlet pipe, and the inlet and outlet pipeline positioned onthe upstream side of the material path is used as a washing liquid outlet pipe; a backwashing liquid enters connected grids from the washing liquid inlet pipe, flows upwards, is used for backwashing abed layer positioned on the upper side of the washing liquid inlet pipe and then is discharged from the washing liquid outlet pipe; and the backwashing liquid does not pass through a rotary valve. Only the single bed layer can be subjected to backwashing, adsorbents and internal components of other bed layers are not influenced, and the backwashing liquid does not pass through the rotary valve, so that the interference to the work of the rotary valve is avoided, and the overall stability of production is ensured.

Description

technical field [0001] The invention relates to a bed layer washing method of a simulated moving bed for adsorption and separation of xylene. Background technique [0002] In the concentration process of p-xylene, the main product of the aromatics complex, the simulated moving bed adsorption system is a relatively common adsorption system. The simulated moving bed system consists of two series-connected adsorption towers and a rotary valve. Two of the adsorption towers are equipped with 12 beds, and the beds of one adsorption tower are 1-12# beds from top to bottom, and the beds of the other adsorption tower are 13-24# beds from top to bottom. #beds. The two adsorption towers are connected in series by a circulation pipeline and two circulation pumps. Corresponding to each bed of each adsorption tower, a bed pipeline is connected to the rotary valve, [0003] Each of the 12 bed pipelines of the two adsorption towers is connected to the rotary valve, and there are 7 materi...

AI Technical Summary

Problems solved by technology

[0005] The backwashing process is: D line—rotary valve—bed pipeline where D line is located—adsorption tower—three beds—bed line where R line is located—rotary valve—discharged from R line as raffinate. , not only backwash the bed whose pressure difference exceeds the set value, but also backwash the other two beds with normal pressure difference, which will affect the two beds with normal pressure difference, and finally affect the two beds with normal pressure difference Yield and purity of toluene product

[0006] When this backwashing method is used, the normal operation of the two beds with normal pressure difference will be disturbed, which will easily cause the bed to be disordered.

Images