煤流化床加压富氧燃烧过程的动态特性  

Dynamic characteristics of pressurized oxy-fuel combustion in fluidized bed

作　　者：魏莉 钟文琪[1] 邵应娟[1] Wei Li;Zhong Wenqi;Shao Yingjuan(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,Southeast University,Nanjing 210096,China)

机构地区：[1]东南大学能源热转换及其过程测控教育部重点实验室,南京210096

出　　处：《东南大学学报（自然科学版）》2020年第2期358-367,共10页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金重点资助项目(51736002);国家自然科学基金面上资助项目(51876037).

摘　　要：为全面深入地了解流化床加压富氧燃烧过程动态特性,建立了流化床加压富氧燃烧过程动态模型,充分考虑了燃烧气氛和燃烧压力改变对炉内燃烧以及烟气组成的影响.基于该模型分别研究了送风氧浓度、燃烧压力以及燃煤量改变时,炉内床温和烟气中各组分体积分数的动态响应,并对其在不同氧浓度和燃烧压力下的响应特性进行研究.研究结果表明,氧浓度、燃烧压力以及燃料量阶跃增加10%会引起炉内床温升高,其中密相区响应速度更快;同时,烟气中各组分体积分数在不同参数扰动下响应各异,主要受到此时炉内燃烧状况以及对应的风量、燃料量改变的影响.此外,床温和烟气中CO2体积分数在压力以及氧浓度突然增加时的动态响应分别在高氧浓度、高燃烧压力下更明显,响应速度更快.整个变化过程中,烟气中CO2体积分数为90%左右,烟气中O2体积分数在8%以下.研究所得相关动态响应规律可对后续控制系统设计及优化提供参考与依据.To understand the dynamic characteristics of pressurized oxy-fuel combustion process, a dynamic model was established considering both the effects of the combustion atmosphere and pressure on combustion and flue gas composition. Based on the model, the dynamic response of bed temperature and the volume fraction of each component in the flue gas with the step increase of inlet O2 concentration, combustion pressure, and coal feeding rate were studied as well as the response characteristics under different inlet O2 concentrations and combustion pressures. The results show that, a 10% step increase of inlet O2 concentration, the combustion pressure and the coal feeding rate can increase the bed temperature inside the furnace, of which the response speed in the dense phase zone is faster. Meanwhile, the dynamic response of the volume fraction of each component in flue gas varies under different disturbances, it is mainly affected by the combustion conditions in the furnace, the corresponding changes in oxidant and coal. In addition, the dynamic variations of the bed temperature and the CO2 volume fraction in the flue gas are more obvious with faster response speed under the higher inlet O2 concentration and the combustion pressure. During the whole process, the volume fraction of CO2 in flue gas is about 90%, with the volume fraction of O2 under 8%. The dynamic characteristics obtained can provide a reference for the design and optimization of the control strategy in the combustion system.

关 键 词：富氧燃烧 加压流化床 动态特性 烟气组分计算 

分 类 号：TQ534[化学工程—煤化学工程]