Study On Biomass Gasification And Kinetics Based On Real-time Thermogravimetric Analysis System

Gasification technology is considered as one of the most promising technologies for converting renewable biomass resources into the synthesis gas which includes the combustible gases of H2,CO,and CH4 in various proportions.In order to improve gasification efficiency and adaptabilities for biomass materials,different types of gasifier including the fixed bed and the fluidized bed,have been developed extensively by the researchers.Compared with the fixed bed,the fluidized bed gasifiers have many advantages,such as high heat transfer rates,high gasification throughput,easy scale-up,etc.However,these gasifiers employ back mixing which leads to high difficulties in two aspects of both the gasifier's design and the running in the optimal operational parameters.The characterization for the reaction process of biomass gasification,including the mass loss rate,syngas composition,tar composition,etc.,which need to be accurately measured due to it directly affects the design and application of the fluidized bed gasifier.In the present study,a real-time thermogravimetric analysis system was developed for providing the insight into the reactivity and gasification process of biomass.Firstly,this paper studied the gasification process of pine sawdust based on the real-time thermogravimetric analysis system.According to the experiments,800 ? of the gasification temperature,0.25 of the equivalent ratio,and 600 kg/(m2·h)of the throughput,were regarded as an optimum conditions for the gasification of pine sawdust in a fluidized bed gasifier.And the ER had a slightly impact on the mass loss rate in the actual working conditions.This experimental method showed a comprehensive perspective for the study of pine sawdust gasification and provided a guideline for the design and application of the fluidized bed gasifier even in the industrial level.Secondly,this paper tried to study the possibility of using dried pig manure in co-gasification process with poplar sawdust through using the real-time thermogravimetric analysis system.The experimental results show that the gasification effect of poplar sawdust is better than that of dry pig manure,and mixed gasification can be achieved when the mixing ratio of poplar sawdust and dry pig manure is below 6:4.This suggests that gasification may be a potential technology for the disposal of pig manure in a green and environmental friendly way while harnessing clean energy in the form of syngas concurrently.Finally,the kinetic analysis of the quality changes of poplar sawdust and dry pig manure in the gasification process was studies.The results showed that the activation energies of poplar sawdust and dry pig manure were between 58?60 kJ/mol and 28?30 kJ/mol respectively according to Arrhenius formula.But the Arrhenius empirical formula is no longer suitable for the kinetic analysis of the gasification reaction when the conversion rate is above 0.3.This shows that the activation energy can't be regarded as a temperature-independent constant in the actual gasification reaction process.