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Title: CO2 Capture by Absorption with Potassium Carbonate

Abstract

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The best K{sup +}/PZ solvent, 4.5 m K{sup +}/4.5 m PZ, requires equivalent work of 31.8 kJ/mole CO{sub 2} when used with a double matrix stripper and an intercooled absorber. The oxidative degradation of piperazine or organic acids is reduced significantly by inhibitor A, but the production of ethylenediamine is unaffected. The oxidative degradation of piperazine in 7 m MEA/2 m PZ is catalyzed by Cu{sup ++}. The thermal degradation of MEA becomes significant at 120 C. The solubility of potassium sulfate in MEA/PZ solvents is increased at greater CO{sub 2} loading. The best solvent and process configuration, matrix with MDEA/PZ, offers 22% and 15% energy savings over the baseline and improved baseline, respectively, with stripping and compression to 10 MPa. The energy requirement for stripping and compression to 10 MPa is about 20% of the power output from a 500 MW power plant with 90% CO{sub 2} removal. The stripper rate model shows that a ''short and fat'' stripper requires 7 to 15% less equivalent work than a ''tall andmore » skinny'' one. The stripper model was validated with data obtained from pilot plant experiments at the University of Texas with 5m K{sup +}/2.5m PZ and 6.4m K{sup +}/1.6m PZ under normal pressure and vacuum conditions using Flexipac AQ Style 20 structured packing. Experiments with oxidative degradation at low gas rates confirm the effects of Cu{sup +2} catalysis; in MEA/PZ solutions more formate and acetate is produced in the presence of Cu{sup +2}. At 150 C, the half life of 30% MEA with 0.4 moles CO{sub 2}/mole amine is about 2 weeks. At 100 C, less than 3% degradation occurred in two weeks. The solubility of potassium sulfate in MEA solution increases significantly with CO{sub 2} loading and decreases with MEA concentration. The base case corrosion rate in 5 M MEA/1.2M PZ is 22 mpy. With 1 wt% heat stable salt, the corrosion rate increases by 50% to 160% in the order: thiosulfate< oxalate<acetate<formate. Cupric carbonate is ineffective in the absence of oxygen, but 50 to 250 ppm reduces corrosion to less than 2 mpy in the presence of oxygen.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
University Of Texas At Austin
Sponsoring Org.:
USDOE
OSTI Identifier:
907880
DOE Contract Number:
FC26-02NT41440
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CARBON DIOXIDE; ABSORPTION; POTASSIUM CARBONATES; SORPTIVE PROPERTIES; AMINES; MATERIALS RECOVERY; AIR POLLUTION CONTROL; MATHEMATICAL MODELS

Citation Formats

Gary T. Rochelle, Andrew Sexton, Jason Davis, Marcus Hilliard, Qing Xu, David Van Wagener, and Jorge M. Plaza. CO2 Capture by Absorption with Potassium Carbonate. United States: N. p., 2007. Web. doi:10.2172/907880.
Gary T. Rochelle, Andrew Sexton, Jason Davis, Marcus Hilliard, Qing Xu, David Van Wagener, & Jorge M. Plaza. CO2 Capture by Absorption with Potassium Carbonate. United States. doi:10.2172/907880.
Gary T. Rochelle, Andrew Sexton, Jason Davis, Marcus Hilliard, Qing Xu, David Van Wagener, and Jorge M. Plaza. Sat . "CO2 Capture by Absorption with Potassium Carbonate". United States. doi:10.2172/907880. https://www.osti.gov/servlets/purl/907880.
@article{osti_907880,
title = {CO2 Capture by Absorption with Potassium Carbonate},
author = {Gary T. Rochelle and Andrew Sexton and Jason Davis and Marcus Hilliard and Qing Xu and David Van Wagener and Jorge M. Plaza},
abstractNote = {The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The best K{sup +}/PZ solvent, 4.5 m K{sup +}/4.5 m PZ, requires equivalent work of 31.8 kJ/mole CO{sub 2} when used with a double matrix stripper and an intercooled absorber. The oxidative degradation of piperazine or organic acids is reduced significantly by inhibitor A, but the production of ethylenediamine is unaffected. The oxidative degradation of piperazine in 7 m MEA/2 m PZ is catalyzed by Cu{sup ++}. The thermal degradation of MEA becomes significant at 120 C. The solubility of potassium sulfate in MEA/PZ solvents is increased at greater CO{sub 2} loading. The best solvent and process configuration, matrix with MDEA/PZ, offers 22% and 15% energy savings over the baseline and improved baseline, respectively, with stripping and compression to 10 MPa. The energy requirement for stripping and compression to 10 MPa is about 20% of the power output from a 500 MW power plant with 90% CO{sub 2} removal. The stripper rate model shows that a ''short and fat'' stripper requires 7 to 15% less equivalent work than a ''tall and skinny'' one. The stripper model was validated with data obtained from pilot plant experiments at the University of Texas with 5m K{sup +}/2.5m PZ and 6.4m K{sup +}/1.6m PZ under normal pressure and vacuum conditions using Flexipac AQ Style 20 structured packing. Experiments with oxidative degradation at low gas rates confirm the effects of Cu{sup +2} catalysis; in MEA/PZ solutions more formate and acetate is produced in the presence of Cu{sup +2}. At 150 C, the half life of 30% MEA with 0.4 moles CO{sub 2}/mole amine is about 2 weeks. At 100 C, less than 3% degradation occurred in two weeks. The solubility of potassium sulfate in MEA solution increases significantly with CO{sub 2} loading and decreases with MEA concentration. The base case corrosion rate in 5 M MEA/1.2M PZ is 22 mpy. With 1 wt% heat stable salt, the corrosion rate increases by 50% to 160% in the order: thiosulfate< oxalate<acetate<formate. Cupric carbonate is ineffective in the absence of oxygen, but 50 to 250 ppm reduces corrosion to less than 2 mpy in the presence of oxygen.},
doi = {10.2172/907880},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Mar 31 00:00:00 EDT 2007},
month = {Sat Mar 31 00:00:00 EDT 2007}
}

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