基于合成气分流的双联流化床气化性能评价

Gasification Performance Evaluation of Interconnected Dual Fluidized Beds with Syngas Recycling

针对双联流化床的热量调控,设计了一种将合成气部分分流至燃烧反应器实现热量平衡的双床气化系统,利用Aspen Plus软件搭建了合成气分流系统模型,对比传统双联流化床系统,评估两种系统在气体组分、合成气热值、有效气体产率以及系统效率方面的差异,研究了气化温度(T)以及水蒸气和生物质质量比r(r=mS/mB)对两种系统热力学性能的影响.研究结果表明:合成气分流至燃烧反应器可以提高合成气热值,而有效气体产率、系统热效率和㶲效率低于传统双联流化床系统;随着气化温度、r的增加,两种系统的气体组分、有效气体产率以及合成气热值的变化趋势相同;两种系统的热效率和㶲效率均随着气化温度、r的增加而减少,系统最高热效率可达74.1%,最高㶲效率可达54.4%.

To balance the heat of interconnected dual fluidized beds,a dual-bed gasification system which recycles a portion of the syngas to the combustion reactor is designed in this paper.The system is modelled using Aspen Plus software.Its gasification performances,such as gas compositions,the lower heating value,effective syngas yield and system efficiency,are evaluated and compared with those of the traditional interconnected dual fluidized beds,and the influences of gasification temperature(T)and the ratio of steam vapor to biomass r(r=mS/mB)on the thermodynamic performances of these two systems are studied as well.Results show that the lower heating value of syngas is increased with the recycling syngas to the combustion reactor,while effective gas yield,thermal effi-ciency and exergy efficiency are lower than those of the traditional interconnected dual fluidized beds.The thermodynamic performances of the two systems show similar trends with the increase of gasification temperature and r.Both of the thermal efficiency and exergy efficiency of these two systems decrease with the rise of gasification temperature and r,and the system’s maximum thermal efficiency and maximal exergy efficiency are as high as 74.1%and 54.4%,respectively.