CO2 Capture by Absorption with Potassium Carbonate [report]

Gary T. Rochelle, Eric Chen, Babatunde Oyenekan, Andrew Sexton, Jason Davis, Marus Hiilliard, Qing Xu, David Van Wagener, Jorge M. Plaza
2006 unpublished
The objective of this work is to improve the process for CO 2 capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K 2 CO 3 promoted by piperazine. 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
more » ... om a 500 MW power plant with 90% CO 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 + /2.5m PZ and 6.4m K + /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 +2 catalysis; in MEA/PZ solutions more formate and acetate is produced in the presence of Cu +2 . At 150 o C, the half life of 30% MEA with 0.4 moles CO 2 /mole amine is about 2 weeks. At 100 o C, less than 3% degradation occurred in two weeks. The solubility of potassium sulfate in MEA solution increases significantly with CO 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. 3
doi:10.2172/899120 fatcat:mm7ulyyzqvgfbbvmahtwcowovm