气流床气化过程多结构单颗粒煤焦燃烧-气化反应特性数值模拟研究  

Numerical simulation on combustion-gasification reaction characteristics of multi-structured single particle of coal char in entrained-flow gasification process

作　　者：赵文静 郭庆华[1] 龚岩 宋旭东 王辅臣[1] 于广锁[1,2] ZHAO Wenjing;GUO Qinghua;GONG YanS;ONG Xudong;WANG Fuchen;YU Guangsuo(Institute of Clean Coal Technology,East China University of Science and Technology,200237 Shanghai,China;State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University,750021 Yinchuan,China)

机构地区：[1]华东理工大学洁净煤技术研究所,上海200237 [2]宁夏大学省部共建煤炭高效利用与绿色化工国家重点实验室,银川750021

出　　处：《煤炭转化》2024年第5期24-33,共10页Coal Conversion

基　　金：国家重点研发计划项目(2022YFA1504703-05);省部共建煤炭高效利用与绿色化工国家重点实验室开放课题(2022-K42);上海市科技创新行动计划启明星项目(21QA1402300).

摘　　要：煤气化技术是现代煤化工的核心技术,气流床气化炉内的高温颗粒是气化反应过程的重要载体,其反应特性与其粒径、孔隙率及在气化炉内所处的反应环境密切相关。目前针对炉内颗粒开展的实验研究均需借助可视化装置,受到了气化炉内复杂的环境、高温内窥镜光路尺寸、内窥镜前端镜片抗颗粒污染能力及成像系统有效分辨率等诸多条件的限制。采用CFD数值模拟的方法,能够在更微小层面和颗粒内部对颗粒燃烧-气化反应过程进行研究,直观观测其行为特性。将颗粒设置为实心结构、凹孔结构和突起结构,比较了三种结构颗粒在不同环境温度和气固两相相对速度条件下的燃烧-气化反应特性。模型验证表明该模型能有效描述单颗粒煤焦反应特性。结果表明:不同结构颗粒模型有相似的火焰形态和温度分布特征,环境温度升高和气固两相相对速度增加均会使颗粒整体反应程度增加,气固两相相对速度对颗粒火焰形态和颗粒内部温度梯度的影响更大;随着气固两相相对速度的增加,结构对颗粒反应特性的影响更加明显;增大接触面积并不总是有利于颗粒整体反应的进行。Coal gasification is a core technology of modern coal chemical industry.The high-temperature particles within the entrained-flow gasifier play a crucial role as carriers in the gasification reaction process.The reactivity of these particles is closely related to their particle size,porosity,and the reaction environment within the gasifier.Current experimental studies on the particles rely heavily on visualization devices;however,these studies are constrained by various factors,including the complex environment inside the gasifier,the optical path dimensions of high-temperature endoscopes,the anti-pollution capability of the endoscope's front lens,and the effective resolution of the imaging system.In this study,computational fluid dynamics(CFD)numerical simulation was employed to investigate the combustion-gasification process of particles at a finer scale,allowing for the direct observation of their behavior.The particles were modeled with solid,cavity,and raised structures to compare the combustion-gasification characteristics of these three models under different environmental temperatures and gas-solid relative velocities.Model validation demonstrated that this approach effectively describes the reaction characteristics of single coal char particles.The results show that the different particle structural models exhibit similar flame morphology and temperature distribution characteristics.Increase in environmental temperature and gas-solid relative velocity both enhance the overall reactivity of the particles,with gas-solid relative velocity having a more significant impact on flame morphology and internal temperature gradients.Furthermore,as gas-solid relative velocity increases,the influence of particle structure on reactivity becomes more pronounced.However,increasing the contact area does not always facilitate the overall reaction of the particle.

关 键 词：颗粒结构 单颗粒模型 煤焦燃烧-气化 颗粒反应特性 数值模拟 

分 类 号：TK16[动力工程及工程热物理—热能工程]