Method for carbon dioxide capture and concentration by partitioned multistage circulation based on mass transfer-reaction regulation

Patent metadata

Field	Value
Publication number	US-11980844-B2
Application number	US-202117566659-A
Country	US
Kind code	B2
Filing date	Dec 30, 2021
Priority date	Jul 26, 2021
Publication date	May 14, 2024
Grant date	May 14, 2024

Abstract

The present invention relates to a method for carbon dioxide capture and concentration by partitioned multistage circulation based on mass transfer-reaction regulation. In the present invention, multiple means such as multistage circulating absorption, intelligent multi-factor regulation, pre-washing and cooling, inter-stage cooling, post-stage washing, slurry cleaning, cooling water waste heat utilization, small-particle-size and high-density spraying, external strengthening field such as a thermal field/ultrasonic field/electric field, and catalysis by composite catalyst are adopted, so that the target for low cost, low energy consumption, stability and high efficiency is realized. The secondary pollutants are effectively inhibited while carbon dioxide is efficiently captured; meanwhile, high-efficiency capture, low-energy desorption, and high-purity concentration of carbon dioxide are implemented. From top to bottom in sequence, the multistage circulation is used to remove aerosols, improves carbon capture efficiency, maintains absorption rate, concentrates solution, which reduces the carbon emission reduction cost.

First claim

What is claimed is:

1. A method for carbon dioxide capture and concentration by partitioned multistage circulation based on mass transfer-reaction regulation, comprising: introducing flue gas into a multistage circulating absorption tower, performing impurity removal and cooling on the flue gas through a pre-washing device disposed in a front of the multistage circulating absorption tower and then successively introducing the flue gas into a first stage carbon dioxide absorption system to (n−1) th stage carbon dioxide absorption system and n th stage washing system, wherein n is greater than or equal to 3; introducing a rich solution into a carbon dioxide desorption tower through a rich solution and lean solution heat exchanger, and discharging a lean solution out of the carbon dioxide desorption tower and introducing the lean solution into the rich solution and lean solution heat exchanger; introducing regenerated gas from the carbon dioxide desorption tower into a carbon dioxide concentration device, and introducing the regenerated gas into a gas-liquid separator through a cooler; connecting an intelligent regulation system respectively to the first to (n−1) th stages carbon dioxide absorption systems, the n th stages washing system, and the carbon dioxide desorption tower; and connecting in series the first to (n−1) th stages carbon dioxide absorption systems and the n th stage washing system in the multistage circulating absorption tower stage by stage from bottom to top;
wherein the pre-washing device is a venturi pre-washing section or a vertical pre-washing tower; washing, impurity removal and cooling water of the pre-washing device is softened water, which is sprayed by an atomizing nozzle, and the washing, impurity removal and cooling water is recycled, and regularly discharged to a wet desulfurization slurry-preparing system as slurry preparing water;
wherein the pre-washing device is the venturi pre-washing section, and the multistage circulating absorption tower is a four-stage circulating absorption tower with n equal to 4; and the method comprises the following steps:
(1) introducing flue gas into the four-stage circulating absorption tower, and performing impurity removal and cooling on the flue gas through the venturi pre-washing section disposed in the front and then introducing the flue gas into the first-stage carbon dioxide absorption system, a second-stage carbon dioxide absorption system, a third-stage carbon dioxide absorption system, and a fourth-stage washing system in sequence,
wherein an absorbent circulates in the first-stage carbon dioxide absorption system with pH of 7.7-9.0 at 49-60° C.;
an absorbent circulates in the second-stage carbon dioxide absorption system with pH of 8.0-10.0 at 44-53° C.;
an absorbent circulates in the third-stage carbon dioxide absorption system with pH of 9.5-11.5 at 40-48° C.; and
softened water circulates in the fourth-stage washing system with pH of 8.5-10.0 at 40-48° C.:
(2) heating the rich solution through rich solution and lean solution heat exchanger to 90-98° C. and then introducing the rich solution into the carbon dioxide desorption tower; after the absorption liquid is heated to 105-115° C., enhancing carbon dioxide desorption by the rich solution under a coupling action of a plurality of fields including thermal field, ultrasonic field, and electric field; and using composite catalyst that is one or more of a γ-Al 2 O 3 /zeolite molecular sieve, an SO 4 2− /ZrO 2 -zeolite molecular sieve, a shell-coated SO 4 2− /ZrO 2 -zeolite molecular sieve, shell-coated SO 4 2− /ZrO 2 —TiO 2 , shell-coated SO 4 2− /CoO—TiO 2 to improve stability and reduce desorption energy consumption; and discharging the lean solution out of the carbon dioxide desorption tower and introducing the lean solution into the rich solution and lean solution heat exchanger for cooling to 60-68° C., and then introducing the lean solution to the second-stage carbon dioxide absorption system;
(3) introducing regenerated steam of the carbon dioxide desorption tower into the carbon dioxide concentration device, cooling the regenerated steam by the cooler to the boiling point of carbon dioxide or below, and introducing the regenerated steam into gas-liquid separator to obtain high-purity carbon dioxide; and
(4) connecting the intelligent regulation system to the first-stage carbon dioxide absorption system, the second-stage carbon dioxide absorption system, the third-stage carbon dioxide absorption system, the fourth-stage washing system, and the carbon dioxide desorption tower, and establishing a global optimization parameter model of carbon dioxide absorption and carbon dioxide desorption by partitioned multistage circulation based on key parameters comprising pH, temperature, and circulation quantity in each stage to implement stable, efficient and low-cost operation of the system.

2. The method for carbon dioxide capture and concentration by partitioned multistage circulation based on mass transfer-reaction regulation according to claim 1 , wherein the first-stage carbon dioxide absorption system comprises a first-section packing layer, a first-section nozzle, a first partition plate, and a first gas lifting cap that are sequentially disposed from bottom to top, and the bottom of the absorption tower communicates with the first-section nozzle through a rich solution pump and a first-section circulating cooler;
the second-stage carbon dioxide absorption system comprises a second-section packing layer, a second-section nozzle, a second partition plate, and a second gas lifting cap that are sequentially disposed from bottom to top, the bottom of the second-stage carbon dioxide absorption system communicates with a second-section circulating tank, and the second-section circulating tank communicates with the second-section nozzle through a second-section circulating pump and a second-section circulating cooler;
the third-stage carbon dioxide absorption system comprises a third-section packing layer, a third-section nozzle, a third partition plate, and a third gas lifting cap that are sequentially disposed from bottom to top, the bottom of the third-stage carbon dioxide absorption system communicates with a third-section circulating tank, and the third-section circulating tank communicates with the third-section nozzle through a third-section circulating pump and a third-section circulating cooler; and
the fourth-stage washing system comprises a fourth-section packing layer and a fourth-section nozzle that are sequentially disposed from bottom to top, the bottom of the fourth-stage washing system communicates with a fourth-section circulating tank, and the fourth-section circulating tank communicates with the fourth-section nozzle through a fourth-section circulating pump and a fourth-section circulating cooler.

3. The method for carbon dioxide capture and concentration by partitioned multistage circulation based on mass transfer-reaction regulation according to claim 1 , wherein a first demister is disposed in the multistage circulating absorption tower, and the first demister is located above the n th stage of washing systems.

4. The method for carbon dioxide capture and concentration by partitioned multistage circulation based on mass transfer-reaction regulation according to claim 2 , wherein the first-section nozzle, the second-section nozzle, the third-section nozzle, and the fourth-section nozzle are bidirectional hollow cone nozzle or unidirectional hollow cone nozzle with Archimedean spiral structure; when the first-section nozzle, the second-section nozzle, and the third-section nozzle use the Archimedean spiral structure, a total of 32 nozzles are arranged in a circumferential direction, and the nozzles are five-head nozzle with pore diameter of 0.8 mm.

5. The method for c

Assignees

• Univ Zhejiang

Inventors

• Gao Xiang
• Zheng Chenghang
• Liu Chang
• Zhou Can
• Zhang You
• Zhao Zhongyang
• Zhang Yongxin
• Zhang Yang
• Li Qinwu
• Weng Weiguo
• Wu Weihong
• Li Qingyi
• Zhang Xiao
• Wang Tao

Classifications

• B01D53/1406 Primary

  Multiple stage absorption · CPC title

• B01D53/1412

  Controlling the absorption process · CPC title

• B01D53/145

  Pretreatment by separation of solid or liquid material · CPC title

• B01D53/1475 Primary

  Removing carbon dioxide · CPC title

• B01D53/1493

  Selection of liquid materials for use as absorbents · CPC title