Mathematical Calculation Of The Biomass Gasification

Biomass is a renewable energy resources, it is paid more and more attention with thenervous of energy. As a main technology of using biomass energy, biomass gasification is ofgreat research significance. In recent years, China's researchers has made important progress inthe biomass gasification and how to industrialization becomes very important. This paper usingchemical process simulation software ASPEN PLUS, with the experimental data in literature,analysis of numerical calculation by biomass gasification, and analyzes the numerical calculationresults.Based on the thermodynamic equilibrium and the Gibbs free energy mini-mization method,a biomass gasification model was established. And then carries on the material balance and theenergy graduated arm to the calculated results. The computed results are compared with theexperimental data or the other numerical results available in literature and good agreementsbetween them are obtained. It proves the validity of the model. Some simulation analysis of themain parameter: gasification agent gasification temperature, equivalence ratio(ER) and steam tobiomass ratio(S/B) are took on gas composition, the yield of gas, heating value and gasificationefficiency.The simulation results of biomass air gasification process show that the ER is the maininfluence factors from the simulation of biomass air gasification process. The temperatureincreases with the rising of the ER, while the yield of gas, heating value and gasificationefficiency are also increased with the increasing ER and the elevate temperature. The peak of theheating value occurs at ER within range of 0.28 to 0.30, cooperated with the temperature rangeof 750℃to 800℃. The simulation results of biomass steam gasification process show that theyield and the proportion of hydrogen are increased as the increasing S/B and the elevatetemperature. So 800℃is chosen as the best value based on the economic consideration. Thebiomass air-steam gasification process based on the above two models is analyzed. It shows thattemperature is the main factor to influence the gasification results. The ER and S/B show a goodlinear relation at a constant temperature. A higher temperature is convenience to produce hydrogen, but if it is too high, the calorific value will be reduced. Low ER and large S/B bothwill reduce the temperature of gasification, which means that the ER and S/B have doubleinfluences on gasification results. When ER equals to 0.3 and S/B equals to 0.5, the yield of gasand the gasification efficiency have the best value.