A Study of Emission Characteristics and CO2 Control Efficiency in EO/FGR Combustion Systems

• Main Authors: Shu-Je Tzeng, 曾書哲
• Other Authors: 謝樹木
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/74797126957507463884

碩士 === 東海大學 === 化學工程學系 === 96 === Enriched oxygen (EO) and flue gas recirculation (FGR) are commonly used to increase combustion efficiency as well as acid gas controlling efficiency in coal combustion systems. This study combines the enriched oxygen and flue gas recirculation (EO/FGR) in an incineration system and uses Aspen Plus (Aspen Tech) to compute the formation of CO2 and acid gases at different combustion conditions by varying the EO percentage and flue gas recirculation ratios. A lab-scale incineration system was set up to verify the simulation results. Results indicate that the concentration of CO2, CO, SO2, HCl and NO increased quite a bit with EO/FGR process. The CO2 fraction is surprisingly high (about 0.79) at 40% O2 concentration and 70% flue gas recycled ratio. The agreement between simulation and experimental results is quite good (about 90%). Further studies on the feasibility of CO2 recovery by absorption with both NaOH and MEA are undertaken by varying L/G ratio, CO2 inlet concentration, and absorbent concentration, respectively. Simulation results indicate that the removal efficiency of CO2 by MEA absorption is quite low for high CO2 concentration. As CO2 fractions get higher than 60%, the removal efficiency drops to 50% operating at 30% MEA. NaOH however, shows better removal efficiencies than MEA does for the absorption of higher CO2 concentrations. Its removal efficiency is higher than 96% even as the CO2 concentration reaches 80%. In addition, the optimum L/G ratio and absorbent concentration are observed to increase with increasing CO2 concentration in the incineration system.