CFB锅炉采用富氧燃烧与常规燃烧方式下的热经济性分析对比

Thermal Economic Analysis and Comparison of CFB Boiler with Oxygen-Enriched and Conventional Combustion

以480t/h的循环流化床锅炉为研究对象,根据热效率和?效率的定义和计算方法,结合热力学第一定律和热力学第二定律,建立了适用于循环流化床锅炉的热效率和?效率的计算模型。分别计算并比较常规空气及富氧气氛(O2/CO2=30/70)下循环流化床锅炉的各项热损失、?损失、热效率和?效率。结果表明:富氧燃烧能够提高循环流化床锅炉的热效率和?效率。但是无论在哪种燃烧方式下,?效率都远远小于热效率,对锅炉热效率的分析只考虑了能量在数量上的利用情况,却没有考虑到锅炉内部各过程的不可逆性所造成的能量品质的下降。而对锅炉?效率的分析,考虑能量的品质,能够更全面的分析锅炉的各项损失及产生部位。

In this paper,a 480 t/h circulating fluidized bed boiler is studied,according to the definition and calculation method of thermal efficiency and exergy efficiency,combined with the first law of thermodynamics and the second law of thermodynamics,the thermal efficiency and exergy efficiency calculation model which are suitable for the circulating fluidized bed boiler are established.The heat loss,exergy loss,thermal efficiency and exergy efficiency of a circulating fluidized bed boiler were calculated and compared for conventional air and oxygen-enriched atmosphere(O2/CO2=30/70).The results show that oxygen enrichment can improve the thermal efficiency and exergy efficiency of circulating fluidized bed boiler.But in either combustion,exergy efficiency is much smaller than the thermal efficiency of the boiler where thermal efficiency analysis considers only the amount of the utilization of energy,but without taking into account the quality of the irreversibility of energy each process inside the boiler caused by the decline,and the exergy efficiency analysis of the boiler considers the quality of energy,and comprehensively analyzes all losses of the boiler and the production parts.