| Biomass gasification is one of the main technologies for its high-efficiency utilization.Water vapor,carbon dioxide,and air are common gasification agents.Many scholars at home and abroad have carried out related studies on the separate gasification experiments of H2O and CO2.There are few studies on the gasification characteristics of wood flour in a mixed atmosphere of H2O and CO2.This thesis is based on the gasification characteristics of CO2 and water vapor in a separate atmosphere,and the gasification characteristics of wood flour in a mixed atmosphere of water and carbon dioxide are studied.At the same time,the effect of adding K2CO3 on the gasification of wood powder was also experimentally studied.There are mainly the following three aspects:(1)Using wood flour as the raw material,the effects of different water-to-carbon ratios and temperatures on the gas composition and gas production during steam vaporization were studied in a fixed-bed reactor,and the residual carbon was measured by scanning electron microscopy(SEM)and XRD characterization analysis,the collected tar was analyzed by GC-MS.The experimental results show that:in the range of S/B=0.25～1.25;as S/B increases,the H2 content gradually increases,and the H2 content increases from 15%to 52.12%.When S/B is greater than 0.75,the growth rate tends to be slow.The temperature increased from 750℃ to 950℃,and the H2 content increased from 13.47%to 49.09%.When S/B=0.75,when the temperature is 750℃,the volume fraction of H2 is 42.49%,the carbon conversion rate was 79.3%,and the calorific value was 6.45MJ/m3,so S/B=0.75 obtaind good experimental results.(2)Based on the steam gasification of wood flour,the influence of the addition of CO2 on the gasification of wood flour was investigated.The feed rate of wood flour is 13.51 g/min,under the conditions of S/B=0.75,and 750℃,and different CO2 volume fractions,the gas composition and gas production will affect the residual carbon.Scanning electron microscopy and XRD characterization analysis were performed.The collected tar was analyzed by GC-MS.The experimental results showed that as the volume fraction of CO2 increased from 1.23%to 8.02%,the hydrogen production rate also increased from 7.5mmol/g to 8.45mmol/g.However,when the CO2 volume fraction is greater than 8.02%,the hydrogen production rate changes slowly,and the gas production rate remains basically unchanged.When CO2 is 8.02%,the volume fraction of H2 is 46.56%,H2/CO is 3.49,the maximum hydrogen production is 8.45 mmol/g,and the carbon conversion rate is 82%.Therefore,the experimental results are better when the volume fraction of CO2 is 8.02%,the volume fraction of H2O is 91.08%,and the residence time is 30s.(3)Using wood flour as the raw material,the effects of different ratios of K2CO3 on the pyrolysis of wood flour were investigated.When S/B=0.75 and the volume fraction of CO2 is 1.23%,the effect of K2CO3 on the gasification of wood flour under a mixed atmosphere of H2O and CO2 were investigated.At 750℃ and the addition of K2CO3 in a mixed atmosphere,the effect of gas composition and gas production is affected,and the residual carbon is analyzed by scanning electron microscopy and XRD.The collected tar is subjected to GC-MS analysis,the experimental results show that under the conditions of S/B=0.75,CO2 volume fraction was 8.02%,H2O volume fraction is 91.08%,H2O and CO2 mixed atmosphere conditions,when the K2CO3 content is 10%As a result,the H2 content was 38.15%,and its mechanism was simply analyzed. |
