L Al-Makhadmeh
Al-Hussein Bin Talal University
Jordan
Title: Oil shale combustion under oxyfuel conditions
Biography
Biography: L Al-Makhadmeh
Abstract
Direct combustion of Jordanian oil shale under oxy-fuel conditions is the first of its kind. Unstaged and staged air-firing as well as combustion at 27% O2/73% CO2 (OF27) was conducted successfully. A 20 kW vertical reactor was used at a combustion temperature of 1200ºC. Oil shale- N conversion rate to NO is higher during unstaged air-firing than oxyfuel combustion; they are 27% and 15% for air-firing and OF27 combustion, respectively. NOx emission can be reduced efficiently by adopting staged combustion technology under oxy-fuel conditions as well as air-firing. In addition, the reduction of simulated recycled NO has been investigated. The actual situation has been simulated by injecting NO in the reactor through the burner. The reduction of the injected NO is more efficient with staging compared to unstaged combustion mode for both air-firing and oxyfuel combustion; the reduction of the injected NO during staged air-firing and OF27 is 100%. During unstaged air-firing the reduction of the injected NO ranges from 61% to 66%, while for unstaged OF27 combustion it ranges from 57% to 65%. The high sulphur content in Jordanian oil shale is considered one of the biggest challenges for its utilization. The oil shale- S conversion rates to SO2 is lower during unstaged oxyfuel combustion compared to air-firing; they are 69% and 49% for air-firing and OF27 combustion, respectively. Direct limestone injection at different molar Ca/S ratios has been investigated under unstaged oxyfuel conditions as well as air-firing. Significant reduction in SO2 emissions is obtained by limestone injection in both combustion modes. At Ca/S molar ratio of 3, the desulphurization efficiencies are 95% and 100% for air-firing and OF27 combustion, respectively.