State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology

CO2气化技术是一种利用CO2作为气化剂生产高品质可燃气体的新型技术,可以协同实现CO2和农林固废的资源化利用,然而CO2气化过程中NOx和SO2的排放特性鲜有报道。针对松木刨花在固定床反应器上开展了CO2气化实验,系统研究了温度的影响。结果表明:在700、800、900℃进行CO2气化时,CO产率分别为0.24、0.52和0.95m3/kg,明显高于H2和CH4的产率,CO是气化产气的主要成分;碳转化率分别为18.36%、36.15%和66.09%;气化效率分别为13.04%、41.59%和92.99%,高温促进了松木刨花的热化学转化。在700~900℃时,NOx中NO的质量浓度峰值和对应时长分别为248、129、138mg/m3和140、195、320s,NO2的质量浓度峰值和对应时长分别为339、191、107mg/m3和115、150、265s,SO2的质量浓度峰值和对应时长分别为3299、3065、2882mg/m3和130、175、180s。NOx和SO2的质量浓度峰值均随温度升高而逐渐降低,对应时长均逐渐增加,表明增加温度有利于降低NOx和SO2的生成速率。然而,NOx和SO2转化率随温度升高而逐渐增大,在900℃分别为49.73%和68.87%,提高温度会强化原料氧和CO2的氧化作用,进而提升NOx和SO2转化率。随着温度升高,NO转化率增加而NO2转化率下降,炉内以CO为主要成分的还原性氛围促使NO2被还原为NO,提高松木刨花的CO2气化温度有利于通过提高CO产率强化该还原作用。

CO2 gasification is a novel technique that uses CO2 as a gasifying agent to produce syngas with a high calorific value for thesynergistic utilization of CO2 and biomass waste. However,the emission characteristics of NOx and SO2 for biomass waste under CO2gasification are rarely investigated. CO2 gasification experiments are carried out on a fixed bed reactor for pine shaving in order to providea temperature reference for thermochemical conversion utilization and pollutant emission control of biomass waste. The results show thatthe yield of CO is 0.24,0.52,and 0.95 m/kg at 700,800,and 900 ℃,respectively,significantly higher than the yields of H2 and CH4. Thus,CO is the major component of the produced syngas. In addition,the carbon conversion yield is 18.36%、36.15%,and 66.09%,respectively,and the CO2 gasification efficiency is 13.04%,41.59%,and 92.99% at 700−900 ℃,respectively. These phenomena indicate that increasingtemperatures can contribute to the thermochemical conversion of pine shaving under CO2 gasification. Moreover,the peak concentrationsand the durations required to reach the peaks of NO in produced syngas are 248,129,and 138 mg/m and 140,195,and 320 s,respectively;those for NO2 are 339,191,and 107 mg/m and 115,150,and 265 s,respectively, and those for SO2 are 3 299,3 065,and 2 882 mg/m and 2x2130,175,and 180 s,respectively. The peak concentrations of both NOx and SO2 gradually decrease and the required durations increase asthe temperatures increase,suggesting that the increase in temperature contributes to a reduction in the yields of NOx and SO2. However,the conversion yields of NOx and SO2 gradually increase as the temperatures increase,reaching 49.73% for NOx and 68.87% for SO2 at900 °C. This shows that a higher temperature can enhance the oxidation effect of oxygen in raw material and gasifying agent (CO2) onthe sulfur and nitrogen in pine shaving,further promoting the conversion yields of NOx and SO2. Furthermore,the conversion yield of NOincreases while that of NO2 decreases with increasing temperatures. The reducing atmosphere in the furnace with CO as the majorcomponent contributes to the NO2 being reduced to NO. Therefore,increasing the temperatures of CO2 gasification for pine shaving canpromote the reduction process of NO2 by increasing the yield of CO.

国家自然科学基金资助项目(52076090)

赵彦,张成,马仑,等.温度对松木刨花CO2气化过程NOx和SO2排放特性影响[J].洁净煤技术,2024,30(11):44−50.

ZHAO Yan,ZHANG Cheng,MA Lun,et al. Effect of temperatures on emission characteristics of NOx and SO2 for pine shaving under CO2 gasification[J].Clean Coal Technology,2024,30(11):44−50.