| Biomass coke gasification is the main link in the process of biomass gasification,but the slow gasification reaction rate,low gasification efficiency and high energy consumption have always been the bottleneck of biomass gasification technology,in order to break through this technical bottleneck and achieve high efficiency and low cost conversion of biomass energy.In order to provide theoretical basis for designing and reforming gasifier,saving energy and reducing consumption in industrial production and improving the quality of product gas.Using corn straw as raw material,CaO and Fe2O3 were selected as catalyst,and the biomass coke particles were prepared by mixing and compressing with raw material,so that the catalyst was loaded to coke.in situ catalysis of gasification reaction is realized within the carbon particles.The kinetics and gas production characteristics of coke water vapor gasification reaction under the synergistic action of CaO?Fe2O3 catalyst and Ca-Fe were investigated by setting up the platform of kinetic test and gasification test.The following conclusions were drawn:?1?Gasification kinetics experiments on biomass coke particles.the pyrolysis and gasification reactions of coke were carried out successively during the gasification process.the pyrolysis reaction followed the three-dimensional diffusion model with a reaction order of 1/3;the gasification reaction followed the shrinking cylinder model with a reaction order of 1/2.The kinetic compensation effect of pyrolysis and gasification was found,and the relationship between pre-finger factor A and activation energy E was obtained by fitting.The reaction rate at a certain temperature can be calculated by Arrhenius formula.?2?CaO activation energy of pyrolysis and gasification reaction decreased by 16 kJ/mol and 24.8 kJ/mol,CaO respectively,which can accelerate the reaction of coke and water vapor,and play a good catalytic role in gasification reaction Fe2O3 The activation energy of pyrolysis reaction decreased by 50.7 kJ/mol,and the activation energy of gasification reaction increased by 7.2kJ/mol.CaO catalysts can reduce in composite catalysts Fe2O3 catalyst agglomeration,weakening Fe coking under high temperature conditions,Ca-Fe synergy,pyrolysis and gasification activation energy are reduced,together to promote the reaction to accelerate.?3?The gas quality of gasification products was improved under the action of catalyst,and the volume fraction of H2 and CO is increased.The gas production rate of Fe-carbon is4.65 L/g?the hydrogen production rate is 3.05 L/g,compared with that of Ca-carbon,and the gas production rate is 1.32 L/g and 1.01 respectively Among the composite catalysts,the gas production rate and the hydrogen production rate were increased with different degrees of Fe catalyst.?4?The comprehensive kinetic analysis shows that Ca-Fe the composite ratio is 5/5,the reaction rate of coke gasification at 850?gasification temperature is not different from that of CaO-carbon,which is nearly twice faster than that of Fe2O3-carbon.The gasification gas production rate of 5/5-carbon is 0.45 L/g and 0.37 higher than that of Ca-carbon L/g,which can not only accelerate the gasification reaction rate to increase the gasification intensity,but also promote the gasification to produce hydrogen,which is more suitable for coke gasification to prepare hydrogen-rich gas. |
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