The Study On The Gasification Reaction Characteristics Of Typical Biomass In Flue Gas Of Oxy-fuel Combustion

Nowadays, environmental pollution and energy shortage are two major challenges for human society. The utilization of biomass, which is abundant, “carbon dioxide neutral” and renewable, has attracted increasingly worldwide attention. Biomass gasification is one of the efficient approaches to convert biomass into gases. The end-use of the product gas is wide, for example, the gas is the raw material of Fischer-Tropsch or fuel cells. gasification technology has some bottlenecks; for example, the preparation for gasification agent cost a lot of money, high reaction temperature require large energy consumption, gasification agent compositions are relatively single, etc. But the flue gas of oxygen-enriched combustion can compensate the bottleneck of gasification technology. Sawdust is one of the forestry residues available in China, the experimental study on the gasification of this typical biomass was performed, and the relevant characteristics were studied in details in flue gas of oxy-fuel combustion.Firstly, gasification of biomass in CO2 was studied in a downdraft gasifier. It was found that the caloric value of syngas reached maximum when the inverter frequency was 3 Hz, the sawdust size was in 60-100 mesh, the carbon molar flow rate in gasification agent is same as that of sawdust. The way of that gasification agent flew into the reactor had obvious influence on syngas, the reason is mainly embodied in the mixed process between gasification agent and biomass, and the residence time in the reactor.Secondly, study on effects of the factors, such as temperature and biomass variety on CO2 gasification were conducted. The carbon conversion rate, the yield and calorific value of syngas, increased with increasing temperature. The increasing trend attributed to the fact that the reaction rate and activity of biomass improved greatly in higher temperature. Under the condition of 900?, the gas flow rate, the calorific value, and the carbon conversion rate can be up to 8.92 L/min, 9.33 KJ/m3, and 71.78%, respectively. In addition, different gasification characteristics are presented with different biomass, sawdust has the best gasification activity.At last, the gasification with the flue gas of oxy-fuel combustion(OFCFG) was studied. The flow rate of product gas and the carbon conversion rate reached maximum values when the oxygen and steam content was 5% and 20%, respectively. The study of co-gasification between coal and biomass showed that the quality of syngas in co-gasification was better than the biomass and coal gasification separately. It was mainly due to the catalytic effects of AAEM on co-gasification of biomass and coal.