《工程科学学报》录用稿，htps:/doi.org/10.13374/i,issn2095-9389.2021.03.22.002©北京科技大学2020 用于CO2捕集的新型石灰煅烧过程的数值分析 张培昆四，张震威，王立 北京科技大学能源与环境工程学院，北京100083 ☒通信作者，E-mail:pkzhang@ustb.edu.cn 摘要：石灰是一种重要的工业原料。常规石灰煅烧工艺中燃料在煅烧窑内燃烧，石灰石分解所释放的二氧化碳(CO) 与烟气混合，CO2捕集需进行气体分离。而采用CO2作为循环载气加热石灰石料块的新型煅烧过程，可避免上述混合问题 从而实现直接捕集石灰石分解产生的CO2。基于CO加热的新型煅烧过程与常规工艺煅烧过程较大不同，为深入理解新 型煅烧过程并对其进行准确设计和有效优化，建立了基于C02加热的石灰煅烧过程的数学模型。塞手模型对一台产量为 200t的煅烧窑进行了模拟计算，获得了气固温差、气相流量、气相温度、料块表面温度、应界面温度和转化率等关键 参数在煅烧窑中的分布情况，并分析了进气温度、进气流量和料块半径三个工况参数对煅烧过程的影响。 关键词：石灰：二氧化碳：煅烧：窑：数值模拟 分类号：TQ021.8/TQ021.3TQ031.3 Numerical analysis of novel lime calcination process for CO2 Capture ZHANG Pei-km☒，ZHANG Zhen-wei,WANG Li School of energy and environmental engineering.University of Science and Technology Beijing 100083,Berjing,China Corresponding author,E-mail:pkzhang @ustb.edu.cn ABSTRACT Lime is an important industrial raw material which is widely used in iron-and steel-making,flue gas desulfurization,construction,and papermaking industries.Lime is generally obtained by calcining limestone in a kiln,that is,limestone is heated and decomposed to generate lime and carbon dioxide (CO2).In the conventional lime calcination process,because the fuel is burned in the shaft kiln,the CO2 released by the limestone decomposition is mixed with the flue gas,resulting in that the CO2 capture requires gas separation. The new lime calcination process using CO2 as a circulating carrier gas to heat the limestone particles can avoid the above mixing problem,thereby directly capturing the CO2 generated by the limestone decomposition,which is expected to reduce carbon emissions from lime production by approximately 70%.However,the new calcination process based on CO2 heating is quite different from the conventional calcination process.To understand the new calcination process and accurately design and optimize it,a mathematical model of the lime calcination process based on CO2 heating was established.Based on the model,a shaft kiln with a capacity of 200 td was simulated and caleulated,and the profiles in the kiln of key parameters such as the gas-solid temperature difference,the gas flow rate,the gas temperature,the particle surface temperature,the reacting interface temperature,and the conversion ratio in the shaft kiln were obtained.Besides,the influence of the three operating parameters(the feed gas temperature,the feed gas flow rate,and the radius of the feeding limestone particle)on the calcination process was analyzed.It was founded that(1)the lower the feed gas temperature,the lower the final conversion ratio,the pinch temperature difference,and the tail gas temperature of the kiln,and the changing trend of the final conversion ration and pinch temperature difference conforms to a quadratic polynomial law,and the changing trend of the tail gas temperature conforms to a linear law,(2)the lower the feed gas flow rate,the lower the final conversion ratio,pinch temperature difference and tail gas temperature of the kiln,and the changing trend of each parameter conforms to a quadratic polynomial law,and(3)the larger the radius of the feeding limestone particle,the lower the final conversion ratio of the kiln,the higher the tail gas temperature,the greater the pinch temperature difference,and the changing trends of various parameters conform to cubic polynomial laws.Compared with the feed gas temperature and the feed gas flow rate,the radius of the feeding limestone particle has a greater impact on the pinch temperature difference and the tail gas temperature when the final conversion ratio changes in the same range. KEYWORDS lime;carbon dioxide;calcination;kiln;numerical simulation 石灰是一种重要的工业原料山，广泛用于钢铁，烟气脱硫，建筑和造纸等行业2。石灰一般通过在 煅烧窑$，中煅烧石灰石而获得，即石灰石受热分解生成石灰和二氧化碳(CO2)。石灰石的分解是吸热反 应，工业中通常使用化石燃料煅烧石灰石。当前，中国己经是世界上最大的石灰生产国，年产量超2亿 吨，约占世界总产量的70%。石灰行业是碳排放的重要来源6，别，2015年中国石灰工业的CO2排放量达 -1-用于 CO2捕集的新型石灰煅烧过程的数值分析 张培昆，张震威，王 立 北京科技大学能源与环境工程学院，北京 100083  通信作者, E-mail: pkzhang@ustb.edu.cn 摘 要：石灰是一种重要的工业原料。常规石灰煅烧工艺中燃料在煅烧窑内燃烧，石灰石分解所释放的二氧化碳（CO2） 与烟气混合，CO2捕集需进行气体分离。而采用 CO2作为循环载气加热石灰石料块的新型煅烧过程，可避免上述混合问题， 从而实现直接捕集石灰石分解产生的 CO2。基于 CO2加热的新型煅烧过程与常规工艺煅烧过程有较大不同，为深入理解新 型煅烧过程并对其进行准确设计和有效优化，建立了基于 CO2加热的石灰煅烧过程的数学模型。基于模型对一台产量为 200 t·d-1的煅烧窑进行了模拟计算，获得了气固温差、气相流量、气相温度、料块表面温度、反应界面温度和转化率等关键 参数在煅烧窑中的分布情况，并分析了进气温度、进气流量和料块半径三个工况参数对煅烧过程的影响。 关键词：石灰；二氧化碳；煅烧；窑；数值模拟 分类号：TQ021.8/TQ021.3/TQ031.3 Numerical analysis of novel lime calcination process for CO2 Capture ZHANG Pei-kun, ZHANG Zhen-wei，WANG Li School of energy and environmental engineering, University of Science and Technology Beijing, 100083, Beijing, China  Corresponding author, E-mail: pkzhang@ustb.edu.cn ABSTRACT Lime is an important industrial raw material, which is widely used in iron- and steel-making, flue gas desulfurization, construction, and papermaking industries. Lime is generally obtained by calcining limestone in a kiln, that is, limestone is heated and decomposed to generate lime and carbon dioxide (CO2). In the conventional lime calcination process, because the fuel is burned in the shaft kiln, the CO2 released by the limestone decomposition is mixed with the flue gas, resulting in that the CO2 capture requires gas separation. The new lime calcination process using CO2 as a circulating carrier gas to heat the limestone particles can avoid the above mixing problem, thereby directly capturing the CO2 generated by the limestone decomposition, which is expected to reduce carbon emissions from lime production by approximately 70%. However, the new calcination process based on CO2 heating is quite different from the conventional calcination process. To understand the new calcination process and accurately design and optimize it, a mathematical model of the lime calcination process based on CO2 heating was established. Based on the model, a shaft kiln with a capacity of 200 t·d-1 was simulated and calculated, and the profiles in the kiln of key parameters such as the gas-solid temperature difference, the gas flow rate, the gas temperature, the particle surface temperature, the reacting interface temperature, and the conversion ratio in the shaft kiln were obtained. Besides, the influence of the three operating parameters (the feed gas temperature, the feed gas flow rate, and the radius of the feeding limestone particle) on the calcination process was analyzed. It was founded that (1) the lower the feed gas temperature, the lower the final conversion ratio, the pinch temperature difference, and the tail gas temperature of the kiln, and the changing trend of the final conversion ration and pinch temperature difference conforms to a quadratic polynomial law, and the changing trend of the tail gas temperature conforms to a linear law, (2) the lower the feed gas flow rate, the lower the final conversion ratio, pinch temperature difference and tail gas temperature of the kiln, and the changing trend of each parameter conforms to a quadratic polynomial law, and (3) the larger the radius of the feeding limestone particle, the lower the final conversion ratio of the kiln, the higher the tail gas temperature, the greater the pinch temperature difference, and the changing trends of various parameters conform to cubic polynomial laws. Compared with the feed gas temperature and the feed gas flow rate, the radius of the feeding limestone particle has a greater impact on the pinch temperature difference and the tail gas temperature when the final conversion ratio changes in the same range. KEYWORDS lime; carbon dioxide; calcination; kiln; numerical simulation 石灰是一种重要的工业原料[1]，广泛用于钢铁，烟气脱硫，建筑和造纸等行业[2-4]。石灰一般通过在 煅烧窑[5,6]中煅烧石灰石而获得，即石灰石受热分解生成石灰和二氧化碳（CO2）。石灰石的分解是吸热反 应，工业中通常使用化石燃料煅烧石灰石。当前，中国已经是世界上最大的石灰生产国，年产量超 2 亿 吨，约占世界总产量的 70％[7]。石灰行业是碳排放的重要来源[6,8]，2015 年中国石灰工业的 CO2排放量达 -1- 《工程科学学报》录用稿，https://doi.org/10.13374/j.issn2095-9389.2021.03.22.002 ©北京科技大学 2020 录用稿件，非最终出版稿