电站锅炉排烟余热能级提升系统分析

将排烟余热用于加热凝结水,参与蒸汽回热循环,是电站锅炉排烟余热有效的利用途径之一。该文利用分析方法,建立电站锅炉排烟余热利用的通用收益模型,分析传统电站锅炉排烟余热利用系统,指出空气预热器存在较大损的缺陷。将空预器单元引入系统,组建了电站锅炉排烟余热能级提升系统,并结合某超临界1000MW机组热力参数,对其进行了收益分析计算。结果表明,排烟温度降低35℃,由于空预器单元 损失下降,与传统排烟余热利用系统相比,能级提升系统利用烟气的能级提升了1倍,机组效率提高了0.75%。

Exergy Analysis of Advanced Boiler Flue Gas Heat Recovery Systems in Power Plants

One of the effective energy saving methods is recovering flue gas waste heat from power station boilers to heat condensation water,which put the waste heat into steam regenerative cycle.A general power profit model of boiler flue gas heat recovery system(BFGHRS) was established by using exergy analysis method.The traditional BFGHRS was discussed extensively and the deficiency of overlarge exergy loss in air preheater was pointed out.Furthermore an advanced BFGHRS was proposed,which combines air preheater with the traditional BFGHRS.Basing on the parameters of a 1000MW supercritical unit thermodynamic system,the power profit analysis of the advanced BFGHRS was accomplished.The results show that,compared with the traditional BFGHRS,the advanced BFGHRS flue gas energy level is doubled and the plant exergy efficiency is increased 0.75% at the flue gas temperature drop of 35 ℃ because of the exergy loss decrement of the air preheater unit.