Comparison of chemical solvents for mitigating CO₂ emissions from coal-fired power plants

There is a growing concern about the effect of greenhouse gases on global warming. Among the many greenhouse gases, CO₂ produced from burning fossil fuels is a major contributor due to the huge volumes emitted into the atmosphere. According to the estimates of the Intergovernmental Panel on Climate Change (IPCC), a worldwide reduction in the emission of greenhouse gases by more than 60% is necessary to avert significant global climate changes. This paper examines the key issues involved in greenhouse gas emissions from coal-fired power plants. At the present time, absorption by chemical solvents appears to be best option for the separation of CO₂ from low pressure flue gas streams. The costs of separation and disposal of CO₂ from existing coal fired, air blown boilers are estimated to increase the cost of electricity by about 75%. Therefore, there is a need to optimize the selection of processing solvents and operating parameters to minimize the cost of separation. Increasing the inlet flue gas pressure did not improve mass transfer rates sufficiently to compensate for the higher compression costs. The effects of other process variables were also examined. In this work, we have examined the cost effectiveness of six ethanolamine-based solvents. Overall, monoethanolamine (MEA) was found to be the best solvent.