US 11,731,922 B2
Method for separating aromatic hydrocarbon using extractive distillation
Longsheng Tian, Beijing (CN); Ming Zhao, Beijing (CN); Wencheng Tang, Beijing (CN); Siliang Gao, Beijing (CN); Nan Yang, Beijing (CN); Zhifeng Bian, Beijing (CN); and Siyuan Qie, Beijing (CN)
Assigned to CHINA PETROLEUM & CHEMICAL CORPORATION, Beijing (CN); and RESEARCH INSTITUTE OF PETROLEUM PROCESSING, SINOPEC, Beijing (CN)
Appl. No. 16/964,665
Filed by CHINA PETROLEUM & CHEMICAL CORPORATION, Beijing (CN); and RESEARCH INSTITUTE OF PETROLEUM PROCESSING, SINOPEC, Beijing (CN)
PCT Filed Jan. 30, 2019, PCT No. PCT/CN2019/073864
§ 371(c)(1), (2) Date Jul. 24, 2020,
PCT Pub. No. WO2019/149212, PCT Pub. Date Aug. 8, 2019.
Claims priority of application No. 201810101427.9 (CN), filed on Feb. 1, 2018.
Prior Publication US 2021/0053893 A1, Feb. 25, 2021
Int. Cl. C07C 7/08 (2006.01); B01D 3/10 (2006.01); B01D 3/14 (2006.01); B01D 11/04 (2006.01); B01D 3/40 (2006.01); C07C 7/00 (2006.01); B01D 11/00 (2006.01)
CPC C07C 7/08 (2013.01) [B01D 3/10 (2013.01); B01D 3/143 (2013.01); B01D 3/40 (2013.01); B01D 11/0492 (2013.01); C07C 7/005 (2013.01); B01D 2011/002 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A method for separating aromatic hydrocarbons by an extractive distillation, comprising following operations:
(1) introducing a hydrocarbon mixture containing aromatic hydrocarbons into middle part of an extractive distillation column; introducing an extraction solvent into upper part of the extractive distillation column; after an extractive distillation, discharging a raffinate containing benzene from the top of the extractive distillation column, wherein the benzene content in the raffinate is 3-40% by mass; and a rich solvent rich in aromatic hydrocarbons is obtained at the bottom of the extractive distillation column,
(2) sending the raffinate discharged from the top of the extractive distillation column to lower part of an extraction column; introducing the extraction solvent into upper part of the extraction column; after a liquid-liquid extraction, discharging a raffinate liquid free of aromatic hydrocarbons from the top of the extraction column; discharging a rich solvent containing benzene from the bottom of the extraction column and introducing the rich solvent containing benzene into upper-middle part of the extractive distillation column, which lies between the positions at which the extraction solvent and the hydrocarbon mixture are introduced, wherein the rich solvent containing benzene is introduced to the 2nd-9th theoretical plates downstream of the position at which the extraction solvent is introduced in the extractive distillation column, and
(3) sending the rich solvent rich in aromatic hydrocarbons obtained from the bottom of the extractive distillation column to middle part of a solvent recovery column; after a vacuum distillation, discharging a streaming comprising aromatic hydrocarbons from the top of the solvent recovery column, and discharging a lean solvent from the bottom of the solvent recovery column.