Biphasic absorbents are thought to be a feasible way for reducing carbon capture energy consumption effectively. While laboratory-scale cyclic studies on biophasic absorbents are abundant

there are scarce studies on the stability verification experiments in industrial bench or pilot plants. In this paper

three absorbents are developed using diethylenetriamine (DETA) as the main amine absorbent

designated as DAGH

DGH

and DAH. Among them

the component ratio of the novel polyamine-based biphasic absorbent DAGH is organic amine: accelerator: phase separation agent: H2O=20:10:30:40; the component ratio of DGH is organic amine: phase separation agent: H2O=25:25:50; the component ratio of DAH is organic amine: accelerator: H2O=(2/7): (1/7): (4/7). The performance of these absorbents is tested on a circulating absorption and desorption device with a simulated flue gas stream of 1 Nm3/h

compared with that of the 30% monoethanolamine (MEA) absorbent. Remarkably

the operating parameters of absorbing agent are optimized by adjusting liquid-gas ratio

pressure

and temperature. The results from long period steady-state operation experiments indicate that the circulating load of DAGH is 1.64 mol CO2/kg solution

significantly better than that of 30% MEA (0.824 mol CO2/kg solution)

and the regeneration heat consumption is 4.80 GJ/t

lower by 28% than that of MEA (6.71 GJ/t)

under the conditions of CO2 capture rate≥90% and CO2 purity≥99%. In addition

because the facility is not equipped with a replenishment system

after 160-hour long-cycle steady-state operation of DAGH

the changes of organic amine

accelerator

and H2O components in the heavy (concentrated) phase are 2.50%

6.36%

and 2.33%

respectively

and the changes of phase separation agent and H2O components in the light (dilute) phase are 6.84% and 18.8%

respectively. DAGH shows preferable stability compared to other absorbents.