Emission of N and S species during pyrolysis and gasification of low-rank coal in an entrained flow reactor
nitrogen and sulphur species,low-rank coal,entrained flow,pyrolysis,gasification
Clean Processing and Conversion of Energy Resources > 4. Comprehensive Utilization of Coal Resources
Draft Paper Accepted
涛 许 / 西安科技大学
The information on the trace gases including nitrogen and sulphur species is essential for environmental concerns and downstream utilization of coal-derived syngas.The emission of nitrogen and sulphur species from two low rank coals (Maddingley and Yallourn coal using an entrained flow reactor were investigated under two different atmospheres: pyrolysis and CO2 gasification. The gaseous nitrogen compounds (HCN and NH3) and sulphur pollutants (H2S and COS) during pyrolysis and gasification were measured. The effects of temperature (1000-1400°C), CO2 concentration (10-40%), and gasification processes (direct and two-step gasification) were assessed under pyrolysis and gasification conditions. It was found that no NH3 and COS were detected during pyrolysis and gasification of coal. High temperature improved H2S and HCN emission during coal pyrolysis. High temperature promoted the HCN release during entrained flow gasification, whereas high CO2 concentration inhibited H2S and HCN emission. The majority of H2S and HCN emissions came from the pyrolysis part during two-step gasification. Compared to two-step coal gasification, direct coal gasification released less H2S and HCN. The results provide important information for the gas cleaning process downstream of entrained flow gasifiers.