Potassium Carbonate Slurry-Based CO 2 Capture Technology

Carbonate slurry process is considered to be one of the potential technologies for large-scale CO 2 capture from coal-based power stations, as it can reduce the participation of water in stripper. In this work, constant volume method was adopted to measure the CO 2 loading in aqueous potassium carbonate solutions at the temperatures of 40, 70, and 120 °C for CO 2 partial pressure from 0.4 to 240 kPa. Absorption heats of CO 2 in aqueous solutions of K 2 CO 3, MEA, and MDEA were measured and compared using true heat flow method. The cyclic CO 2 equilibrium loading increases with K 2 CO 3 concentration increase, which is a benefit for CO 2 capture. However, the increased viscosity leads to a decrease of the apparent absorption rate. Absorption heat depends on temperature, K 2 CO 3 concentration, and CO 2 loading. Compared to MEA, potassium carbonate solution has a lower absorption heat. Generated potassium bicarbonate crystallization can enhance CO 2 absorption but also increase absorption heat. Slurry desorption can reduce 34% regeneration energy and 37% cooling duty of CO 2 -rich gas compared to the traditional carbonate process without precipitation at the same regeneration condition of temperature elevation from 70 to 130 °C.