PILOT PLANT FOR CO_2 CAPTURE USING AQUEOUS PIPERAZINE/POTASSIUM CARBONATE

摘要

The removal of CO_2 typically uses an absorption/stripping system with an amine solvent, such as monoethanolamine (MEA). A new solvent, piperazine promoted potassium carbonate, has been developed. A solution of 2.5m piperazine (PZ) and 5m potassium bicarbonate (K~+) has a CO_2 absorption rate 1 to 3 times faster than 7m MEA (30 wt%). The solvent also has a lower heat of CO_2 absorption, which should reduce the heat requirement for stripping. A rigorous model absorber model has been developed to estimate absorber performance. The model predicts an equilibrium pinch in the absorber near the point of maximum liquid temperature. Experiments have been conducted on a pilot plant with solvent compositions containing 4.2 m K~+/ 2.1 m PZ and 5 m K~+/ 2.5 m PZ. The CO_2 concentration was varied from 3 to 13%. The gas and liquid rates were varied from 120-800 cfm and 2.4-10 gpm, respectively. The CO2 removal rates ranged from 85 to 99.8 percent.