CO2 capture from power stations running with natural gas (NGCC) and pulverized coal (PC): Assessment of a new chemical solvent based on aqueous solutions of N-methyldiethanolamine + triethylene tetramine

AbstractPower plants, except the nuclear ones, release relatively high amounts of carbon dioxide. The increasing use of coal to detriment of natural gas will contribute to increase the anthropogenic CO2 emissions. Improving thermal efficiencies will slightly reduce the CO2 emissions but it is essential to design, in the same time, processes recovering carbon dioxide at low cost. A comparison between various concepts suggests that, in the short and medium term, chemical absorption is one of the most interesting processes. Kinetics is an important characteristic when designing absorption columns, but one must keep in mind the energy requirement for the solvent regeneration. The present study aims to assess the performances of a new aqueous solvent (blend of methyldiethanolamine (MDEA) and triethylene tetramine (TETA)) and compare them with more conventional solvents such as aqueous solutions of MDEA and of monoethanolamine (MEA). The post-combustion recovery process using these different solvents was evaluated using the software Aspen Plus™. The CO2 concentration in the flue gas was 5 vol% for a Natural Gas Combined Cycle power plant (NGCC) and 14 vol% for a Pulverized Coal power plant (PC). The simulations show that the new solvent containing the blend of MDEA and TETA reduces the energy requirement for the solvent regeneration: 2.55 GJ t−1 CO2 for the PC power plant and 3.00 GJ t−1 CO2 for the NGCC power plant. This represents a decrease ranging from 15 to 25% compared to the results obtained with MEA and MDEA