| In the face of increasingly serious energy and environmental issues,efficient development and utilization of renewable energy is an important solution.Biomass gasification is regarded as one of the most promising ways to use biomass.However,due to the problems of high cost,complicated process,and poor quality of syngas after gasification,some scholars have been burning chemical chains.Based on the oxygen carrier gasification technology of biomass,the lattice oxygen of the oxygen carrier is used instead of the conventional gasification medium to effectively improve these problems.At present,most of the researches at home and abroad are oxygen carrier combustion and oxygen carrier cycle hydrogen production,and the raw materials are mostly coal.There is less research on syngas generation from biomass oxygen carrier gasification.Therefore,it is necessary to carry out gasification of biomass oxygen carrier to prepare synthesis gas.In this paper,a series of iron-based composite oxygen carriers were prepared by impregnation.XRD,H2-TPR,SEM and thermogravimetric analysis were used to characterize and evaluate the iron-based composite oxygen carriers.The effects of different carriers and Fe2O3 loadings on the structure,resistance to carbon deposition,redox properties,and selectivity of the oxygen carrier gasification product of the composite oxygen carrier were investigated.The gasification characteristics of biomass oxygen carrier were tested on a self-made gasification reformer of biomass oxygen carrier to prepare synthesis gas,and the gasification process of biomass oxygen carrier gasification steam reformation was numerically simulated.In addition,the process for gasification of biomass oxygen carriers to syngas was optimized.Response surface methodology(RSM)was used to study reaction temperature,mass ratio of water vapor to biomass,mass ratio of oxygen carrier to biomass,and reaction time to synthesis.The impact of gas.A regression model was established to evaluate the relationship between the ratio of H2/CO in synthesis gas and reaction temperature,time,OC/B,and S/B.The results show:(1)Different inert carriers have different selectivity for the production of syngas by gasification of biomass oxygen carriers,among which Al2O3 supports the preparation of synthesis gas with a high H2/CO ratio.The larger the loading of Fe2O3,the more the lattice oxygen of the composite oxygen carrier itself.When the loading is 60%,the activity and stability of the composite oxygen carrier reach the optimal value.The H2/CO ratio in the synthesis gas also reaches a maximum at this time.The surface of the oxygen carrier after use has a carbon deposition phenomenon,and the carrier has different carbon deposition conditions.Thermogravimetric analysis showed that when the carrier was Al2O3,the second weight loss peak of the composite oxygen carrier was the smallest,and the carbon deposition of the composite oxygen carrier was the least.At the temperature of 400-600?,the reaction rate of the four kinds of composite oxygen carriers reached the maximum,and the mass replenishment rate of lattice oxygen at this temperature was lower than that of the biomass carbon.(2)It is concluded from the experiments of gasification characteristics of biomass oxygen carrier that increasing the reaction temperature is beneficial to the gasification reaction of oxygen carrier of biomass when the temperature is 750? to 950?,and the addition of water vapor can increase the content of H2 in the synthesis gas,and excessive oxygen carriers will lead to The CO2 content in the syngas increases.Through the numerical simulation of gasification steam reforming of biomass oxygen carrier,we can know that controlling the reaction path and reaction time can improve the oxygen carrier gasification process of biomass.(3)When the reaction temperature is 900?,the total H2 and CO content and H2/CO ratio reach the maximum value.When S/B was 2.8,the total content of H2 and CO in synthesis gas reached the maximum value,and the H2/CO value,gas production rate and carbon conversion rate were all significantly improved.The carbon conversion rate reached the maximum at OC/B of 1.0,and the gas production rate increased significantly with the increase of OC/B.The prolongation of the reaction time resulted in a significant increase in the H2 content in the synthesis gas.When the reaction time is 20 min,the quality and yield of the synthesis gas reach the optimum value.The optimal process parameters were obtained by RSM,a quadratic model was established,and the feasibility was verified by analysis of variance.The optimum conditions were as follows: reaction temperature was 899.55?,time was 20.31 min,OC/B was 1.02,S/B ratio was 2.89,and H2/CO value obtained under optimal conditions was 2.23.It provides theoretical support for the preparation of syngas from rice straw,and demonstrates the great prospects for energy utilization of rice straw waste. |
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