CO2 absorption rate and capacity of semi-aqueous piperazine for CO2 capture. (June 2019)

• Record Type: Journal Article
• Authors: Yuan, Ye; Rochelle, Gary T.
• Is Part Of: International journal of greenhouse gas control. Volume 85(2019)
• Page Start: 182
• Page End: 186
• Publication Date: 2019-06
• Subjects: Piperazine -- Semi-aqueous -- Amine scrubbing -- CO2 absorption rate; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2019.03.007
• Languages: English
• ISSNs: 1750-5836

Abstract

Highlights: CO2 solubility and absorption rate measured in piperazine/H2 O/sulfolane or imidazole. Sulfolane and imidazole increase P*CO2 but capacity is unchanged. Sulfolane and imidazole increase viscosity but rate is unchanged. Abstract: Aqueous piperazine (PZ) is a representative second-generation solvent for flue gas amine scrubbing; however, the solid precipitation of aqueous PZ at lean loading needs to be addressed. Semi-aqueous piperazine composed of PZ, water, and a physical solvent (sulfolane or imidazole) has been characterized in a wetted wall column. No precipitation was observed in 5 m PZ in SUF/water or IMI/water in the loading range of 0.15–0.45 mol CO2 /mole alkalinity at 20–60 °C. The average viscosity at 40 °C in this range is about 25 cP in 5 m PZ in 1SUF/1water, 9.5 cP in 5 m PZ in 1SUF/3water, and 15 cP in 5 m PZ in 1IMI/1water, greater than 4 cp in 5 m aqueous PZ. Adding SUF or IMI into aqueous PZ increases absorption rate (kg ') at lean and median loading but decreases kg ' at rich loading. kg ' in semi-aqueous PZ increases as temperature decreases from 60 to 20 °C. At 40 °C, kg 'avg in 5 m semi-aqueous PZ is 15–35% greater for the operating range of 0.1–5 kPa P*CO2, and 20–50% greater for 0.1–1.5 kPa P*CO2 (natural gas conditions). CO2 cyclic capacity slightly increased after adding SUF or IMI.