生物质三组分在O_(2)/CO_(2)气氛下的着火行为研究  

Ignition behaviors of the three components of biomass in O_(2)/CO_(2) atmosphere

作　　者：程偲哲 邹春[1] 姚青 娄春[1] 王树森 经慧祥 梅媚 CHENG Sizhe;ZOU Chun;YAO Qing;LOU Chun;WANG Shusen;JING Huixiang;MEI Mei(State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China;Key Laboratory of Healthy&Intelligent Kitchen System Integration of Zhejiang Province,Ningbo 315336,China;Ningbo Fotile Kitchen Ware Company,Ningbo 315336,China)

机构地区：[1]华中科技大学煤燃烧国家重点实验室,湖北武汉430074 [2]浙江省健康智慧厨房系统集成重点实验室,浙江宁波315336 [3]宁波方太厨具有限公司,浙江宁波315336

出　　处：《洁净煤技术》2021年第2期161-169,共9页Clean Coal Technology

基　　金：国家自然科学基金资助项目(51776081)。

摘　　要：生物质的富氧燃烧技术结合了生物质燃烧与富氧燃烧的优点,既能减少化石燃料的使用,又易实现CO_(2)捕集。富氧燃烧的最显著特点是气氛中的氧气体积分数大于21%,其对生物质着火行为的影响至关重要。纤维素、半纤维素和木质素是生物质的3种主要组分,研究其在富氧条件下的着火及燃烧行为,可为生物质的着火及燃烧行为研究提供重要依据。利用滴管炉结合高速摄像机,研究了粒径74~154μm的纤维素、半纤维素和木质素在温度1273 K,氧气体积分数21%、30%、50%、70%和100%的O_(2)/CO_(2)气氛中的着火行为,并利用辐射能测温技术计算着火图片中的颗粒温度。结果表明,随着O_(2)体积分数增加,纤维素、半纤维素由联合着火以及木质素由均相着火均转为非均相着火,纤维素、半纤维素、木质素着火机理发生转化的O_(2)体积分数分别为30%、70%和50%。纤维素着火对O_(2)体积分数变化敏感,氧气体积分数超过30%时,纤维素焦率先发生着火。半纤维素和木质素的升温速率随氧气体积分数的升高而提高,半纤维素是由于挥发分在燃烧过程中随着氧气体积分数的增加,其燃烧比例减弱,焦燃烧比例增加,而木质素因为氧气体积分数的升高强化了木质素焦燃烧。半纤维素和木质素燃烧时间均随氧气体积分数的升高而缩短,两者都是由于氧气体积分数升高强化了焦的燃烧。另外,在较高氧气体积分数下木质素焦会发生熔融并膨胀,形成明显的膨胀火焰。The oxy-fuel combustion of biomass technology combines the advantages of oxy-fuel combustion and biomass combustion,which can not only reduce the consumption of fossil fuels,but also easily achieve CO_(2) capture.The most significant feature of oxy-fu⁃el combustion is that the oxygen concentration in the atmosphere is more than 21%,which has a significant effect on the ignition behavior of biomass.Cellulose,hemicellulose,and lignin are the three main components of biomass.Therefore,studying the ignition and combustion behavior of these three components under oxy-fuel conditions is the basis for the study of biomass ignition and combustion.In this work,a drop tube furnace combined with a high-speed camera were utilized to study the ignition behaviors of cellulose,hemicellulose,and lignin particles of 74-154μm at the temperature of 1273 K under O_(2)/CO_(2) atmosphere with oxygen concentration of 21%,30%,50%,70%,and 100%.The radiant energy analysis technology was used to calculate the temperature of particles in the ignition picture.The results show that cellulose and hemicellulose change from hetero-homogeneous ignition to homogeneous ignition and lignin changes from homogeneous ignition to heterogeneous ignition with the increase of O_(2) concentration.The ignition mechanisms of cellulose,hemicellulose,and lig⁃nin change at 30%,70%,and 50%oxygen concentration,respectively.The ignition of cellulose is sensitive to the change of O_(2) concentra⁃tion.When the O_(2) concentration exceeds 30%,the cellulose char ignites firstly.The heating rates of hemicellulose and lignin increase with the increase of O_(2) concentration.For hemicellulose,it can be attributed to that the burning proportion of hemicellulose volatiles decreases and the burning proportion of hemicellulose char increases with the increase of O_(2) concentration during the combustion process.For lignin,it is because the combustion of lignin char is enhanced with the increase of oxygen volume fraction.Moreover,the combustion time of hemi⁃cellulose

关 键 词：纤维素 半纤维素 木质素 氧气体积分数 着火行为 

分 类 号：TK6[动力工程及工程热物理—生物能]