# US 2014/0155674 A1 · Process and device for separation by simulated moving bed adsorption > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0155674 A1 - Document ID: US20140155674A1 - Status: Published application - Kind: A1 - Application number: 14/234,807 - Filed: 2012-07-16 - Published: 2014-06-05 - Earliest claimed: 2011-07-28 - Assignees: China Petroleum & Chemical Corporation; Research Institute of Petroleum Processing, Sinopec - Inventors: Dehua Wang; Zhuo Yu; Huiguo Wang; Jiangfeng Ma - Web page: https://patentgrep.com/patent/US20140155674A1 ## CPC - C07C 7/12: by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers - B01D 15/02: with moving adsorbents - B01D 15/1835: {Flushing} - C07C 7/13: by molecular-sieve technique - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract The present invention relates to a process for separating isomers by simulated moving bed (SMB) adsorption, comprising separating the raw materials comprising isomers by SMB adsorption, said SMB comprising many adsorption beds each of which is equipped with grids, each of the grids being equipped with the feedstock inlet and outlet pipeline of the bed, the feedstock charged into and discharged from SMB at least comprising feedstocks, desorbent, extract, and raffinate, the extract being enriched with the target product, characterized in that the extract is used as a flushing liquid and respectively charged to first or second bed at the upstream of the feedstock charging position and to one of second to fourth beds at the downstream of the extract withdrawing position. Such process is used for separation of C8 aromatic isomers by adsorption, and can improve the capacity of the device while effectively increasing the purity of the target product separated by adsorption. ## Claims ### Claim 1 A process for separating isomers by simulated moving bed (SMB) adsorption, comprising separating the feedstock comprising isomers by SMB adsorption, said SMB comprising many adsorption beds each of which is equipped with grids, each of the grids being equipped with the materials charging and discharging pipeline of the bed, the materials charged into and discharged from SMB at least comprising feedstock, desorbent, extract, and raffinate, the extract being enriched with the target product, characterized in that the extract is used as a flushing liquid and respectively charged to first or second bed at the upstream of the feedstock charging position and to one of second to fourth beds at the downstream of the extract withdrawing position. ### Claim 2 (depends on 1) The process according to claim 1, characterized in that a desorbent is charged to first or second bed at the upstream of the extract withdrawing position to wash pipeline of the bed. ### Claim 3 (depends on 1) The process according to claim 1, characterized in that, in a step time, the volume charging amount of the flushing liquid charged to first or second bed at the upstream of the feedstock charging bed is from 1.0 to 2.5 times of the total volume of the pipelines from the flushing liquid control valves to the grids of the bed of adsorbent. ### Claim 4 (depends on 1) The process according to claim 1, characterized in that, in a step time, the volume charging amount of the flushing liquid charged to one of second to fourth beds at the downstream of the extract withdrawing position is from 0.5 to 1.5 times of the total volume of the pipelines from the flushing liquid control valves to the grids of the bed of the adsorbent. ### Claim 5 (depends on 1) The process according to claim 1, characterized in that the separation process by adsorption is the liquid phase separation process. ### Claim 6 (depends on 1) The process according to claim 1, characterized in that, in a step time, the charging and discharging materials along with the flow direction of the materials in SMB are in a sequence of the desorbent, extract, feedstock and raffinate. ### Claim 7 (depends on 1) The process according to claim 1, characterized in that said SMB comprises many beds, which are divided into the desorption zone, purification zone, adsorption zone and isolation zone. ### Claim 8 (depends on 1) The process according to claim 1, characterized in that the isomers separated by adsorption are xylenes and ethylbenzene, and the target product to be separated by adsorption is p-xylene or m-xylene. ### Claim 9 (depends on 1) The process according to claim 1, characterized in that the desorbent for separation by adsorption is p-diethyl benzene or toluene. ### Claim 10 A device for separating isomers by simulated moving bed (SMB) adsorption, comprising SMB and materials inlet and outlet pipeline, said SMB comprising many beds of adsorbent each of which is equipped with grids, each of the grids being equipped with the materials inlet and outlet pipeline of the bed, two flushing liquid pipelines being set up in parallel on the materials inlet and outlet pipeline of the bed, each of the flushing liquid pipelines being equipped with an on-off valve, the extract being used as the flushing liquid, the flushing liquid in one flushing liquid pipeline being charged to first or second bed at the upstream of the feedstock charging bed, and the flushing liquid in the other flushing liquid pipeline being charged to one of second to fourth beds at the downstream of the extract withdrawing position. ### Claim 11 (depends on 10) The device according to claim 10, characterized in that the grids of each of the bed are equipped with a materials inlet and outlet pipeline, and many on-off valves connected in parallel are set up on the pipeline to control the charging and discharging of each materials of the bed. ### Claim 12 (depends on 10) The device according to claim 10, characterized in that 6 to 7 on-off valves are set up on each materials inlet and outlet pipeline of the bed. ### Claim 13 (depends on 10) The device according to claim 10, characterized in that each bed is equipped with a pipeline in which the desorbent is used as the flushing liquid, and the charging position is the bed at the upstream of the extract withdrawing position.