Results from Trialling Aqueous NH3 Based Post Combustion Capture in a Pilot plant at Munmorah Power Station: Desorption

Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) and Delta Electricity have tested an aqueous ammonia based post combustion capture (PCC) process in a pilot plant at Munmorah black coal fired power station. This paper presents and discusses the experimental results obtained and primarily focuses on the desorption section. A high purity of CO2 product was obtained at the stripper gas outlet with the CO2 volumetric concentration generally between 99-100% and the remainder being water and NH3. An increase in stripper pressure/temperature can lead to a decrease in NH3 concentration in the CO2 product. The NH3 concentration can be controlled within 200 ppvm without wash at a stripper pressure of 850 kPa (the maximum pressure tested) at a stripper gas outlet temperatures of 20-25 degrees C. The solid precipitation occurred in the stripper condenser and reflux lines. Due to the low ammonia content in the solution, CO2 content in the solution was low and generally more than 50% of regeneration energy was used to heat up the solvent under the pilot plant conditions. The lowest regeneration energy obtained from the pilot plant trials is 4-4.2 MJ/kg CO2 captured. The effect of various parameters including solvent flow-rate and stripper temperature/pressure in the solvent on the regeneration energy was investigated.