(46e) Thermal Plasma Gasification of Different Coals with Carbon Dioxide
AIChE Spring Meeting and Global Congress on Process Safety
Tuesday, March 15, 2011 - 10:10am to 10:35am
Carbon dioxide emissions from conventional coal-fired power plants constitute the majority CO2 emissions in the U.S. Mitigation of CO2 by chemical conversion provides an alternative method to reduce the CO2 emissions from coal gasification process with the benefit of eliminating energy-intensive CO2 sequestration step. A CO2 emission reduction process, which utilizes CO2 as oxygen source by reacting CO2 with coal to produce CO via the reverse Boudouard reaction (CO2 (g) + C (s) → 2CO, DHo = +172.6 kJ/mol, DGo = +119.9 kJ/mol) in a thermal plasma reactor, is reported in this paper. Since the reaction has a positive DGo, high temperature from thermal plasma shifts the equilibrium favorably to the right. A thermal plasma spray system was adapted for this application. The reaction temperature can be changed by adjusting the thermal plasma amperage. Three different coals were tested with CO2 under thermal plasma condition (650 A, 28 V), and the CO2 conversion rate was lignite coal 73%, subbituminous coal 77%, and bituminous coal 88%, respectively. Temperature effect study shows that the CO2 conversions increased with the temperatures, which is in accordance with the fact that the reaction of CO2 with carbon is an endothermic reaction.