化工进展2025，Vol.44Issue(4)：2008-2019,12.DOI:10.16085/j.issn.1000-6613.2024-0566
光热驱动褐煤固定床气化过程热质传递规律
Heat and mass transfer law of photothermal-driven lignite fixed-bed gasification process
摘要
Abstract
The photothermal heat source can solve problems such as low elemental utilization in low and medium coal gasification processes,but the reaction characteristics are different from those of conventional coal gasification processes due to changes in the properties of the heat source and the heat transfer method,and the introduction of the mixing agent for CO2 dissipation will have an impact on the temperature field in the reactor.In order to study the above problems,this paper constructed a lignite fixed-bed gasification reactor with a photothermal heat source using the multi-field coupling software Comsol Multiphysics,and investigated the influence laws of the temperature distribution and product composition as well as the changes of the heat and mass transfer behaviors in the reactor with different thermal conductivity characteristics of the gasification mediums steam,carbon dioxide and different ratios of the mixing gasification agents.As the proportion of CO2 added to the gasification agent increased from 0 to 100％,the viscosity and density of the fluid continued to increase,resulting in an increase in the viscous force between the fluids and a decrease in the momentum transfer,and the convective heat transfer coefficient between the gas-solid phases decreased from 26.3W/(m2·K)to 22.7W/(m2·K).Compared with steam gasification,the addition of CO2 reduced the particle gasification temperature and the reaction rate of coal gasification,but the increase of CO2 concentration was conducive to increase the reaction rate of semi-coke CO2 reduction.Under the combined effect,the complete gasification time of coal coke particles did not change significantly.In addition,the optical heat saving heat medium heating mode made the reactor bed temperature curve overall"funnel-shaped",which led to the extension of the particle gasification time in the center by 70min,and after the mixing of CO2,the reduction of thermal conductivity made the temperature curve appeared obvious"lag effect".Finally,by adjusting the proportion of CO2 added to the gasification medium,it was found that when the proportion of CO2 added increased to 40％,the gasification medium exhibited the behavior of exogenous CO2 absorption and its CO2 absorption reached 0.013g/g.As the gasification temperature increased,the reaction rate of CO2 gasification increased,which ultimately showed an increase in CO2 consumption and the effective syngas yield,but a decrease in the H2/CO ratio.关键词
煤气化/气化介质/传热/温度分布/反应速率Key words
coal gasification/gasification medium/heat transfer/temperature distribution/reaction rate分类
化学化工引用本文复制引用
袁梦丽,宋云彩,李文英,冯杰..光热驱动褐煤固定床气化过程热质传递规律[J].化工进展,2025,44(4):2008-2019,12.基金项目
国家重点研发计划(2022YFE0208400) （2022YFE0208400）
山西省重点研发计划(202202090301002) （202202090301002）
山西省自然科学基金(20210302124096) （20210302124096）
中央高校基本科研业务费专项资金(2022ZFJH04). （2022ZFJH04）
