Study On Gasification Simulation And Optimization Of Corn Straw

More and more attention has been paid to the development and utilization of biomass energy.Our country is rich in corn straw resources,but the utilization rate is low.In order to improve the utilization rate of corn straw,the gasification process of corn straw in downdraft fixed bed gasifier was simulated and optimized by software Aspen Plus based on experimental analysis,overcoming the limitations and complexities of experiments,it has certain significance for the optimization of engineering.In this paper,the basic characteristics,pyrolysis process and co-pyrolysis of corn straw,corn kernels and corn cob as well as the mixture of the whole plant in proportion to the whole plant were studied experimentally.The results show that the content of oxygen-containing functional groups is high in each sample.A more intense pyrolysis process can treat the pyrolysis reaction as a first-order reaction.The gases in the pyrolysis process are mainly CH₄,CO₂,CO,H₂O.The precipitation is mainly in the stage of volatilization analysis.The whole plant mixed sample showed mutual inhibition in the pyrolysis zone of 30⁹00°C,and the overall inhibition was mainly the effect of pyrolysis interval 336⁶47°C.The corn stover was used as the gasification material,and the model of the lower suction fixed bed gasifier was established by software Aspen Plus.The correctness of the model was verified by experimental data.The effects of air equivalent ratio（ER）,steam/corn stalk mass ratio（S/B）and gasifier temperature on the main gasification indexes were studied by using the model.The results show that under the air gasification agent,the increase of ER significantly reduces the gas calorific value and gasification efficiency.Under the air-steam mixed gasification agent,the increase of ER significantly reduces the gas calorific value and gasification efficiency.The increase of S/B causes the gas calorific value to decrease slightly and the gasification efficiency to increase slightly.The increase of the temperature of the gasifying agent causes the calorific value of the gas to decrease first and then increase,and the gasification efficiency is obviously increased.Under different ER,the different gasification agent temperature has different effects on the gasification index.The temperature of the fixed gasification agent decreases with the increase of ER,and the gas calorific value and gasification efficiency decrease.With fixed ER,the gasification efficiency increases with the increase of gasification agent temperature.With the increase of ER,the growth rate of gasification efficiency decreases with the increase of gasification agent temperature.Under different gasification agent temperatures,different S/B influences the gasification index differently.The temperature of the fixed gasification agent changes little with the increase of S/B,and the gas heat value decreases.As the temperature of the gasifying agent increases,the magnitude of the decrease in the calorific value of the gas first increases and then decreases.When the S/B is fixed,the increase in the temperature of the gasifying agent increases the gasification efficiency.The orthogonal experiment was conducted to study the optimization scheme of the influence of gasification factors on gasification indexes.The results show that the primary and secondary factors affecting gas yield and gas calorific value are ER>S/B>gasifier temperature,and the primary and secondary factors affecting gasification efficiency are ER>gasifier temperature>S/B.ER has a significant effect on gas yield,gas calorific value and gasification efficiency.S/B has a significant effect on gas yield and gas calorific value,and gasifier temperature has a significant effect on gasification efficiency.Comprehensive analysis,ER plays the most important role in the gasification process.The optimal process parameter ER is 0.25,S/B is 0.5,and the gasification agent temperature is 800°C.