低CO_2排放的太阳能/甲醇互补系统热力经济性分析

Thermo-Economic Analysis of the Low-CO_2 Emission Solar/Methanol Hybrid Power Generation System

基于品位匹配和多能源综合梯级利用的原则,本文提出了低CO_2排放的太阳能与化石能源互补发电系统LESOLCC,并对其进行了热力经济性能分析。所提系统以甲醇为燃料,中低温太阳能首先提供甲醇重整反应的反应热,从而转化为富氢合成气的化学能,实现品位提升;其次通过燃烧前对CO_2的捕集,实现燃料的清洁燃烧,最终在高效联合循环中实现其热功转换。结果表明:基本工况下,系统当量效率达到55.1%,比投资为833$/kW,发电成本为0.124$/kWh,回收期17年;与相同化石燃料输入及CO_2捕集水平的尾气捕集CO_2的常规燃气-蒸汽联合循环(CC-Post)相比,发电成本下降了10.1%,充分显示其优越性。

A novel gas-steam combined cycle power systems integrated with low/mid temperature solar heat thermo-chemical conversion and CO_2 capture,with methanol as the input fuel,have been proposed and analysed.Solar heat collected at 200～300℃is used to heat the endothermic methanol reforming reaction and is thereby converted into syngas chemical energy;the produced syngas is enriched with H_2 and CO_2（24.4%CO_2 and 74.7%H_2 by volume）,thus is ready for pre-combustion decarbonization.The processed CO_2-lean syngas is used to fuel a gas/steam combined cycle.The results show that exergy efficiency of 55.1%can be achieved;the specific total plant cost is 833$/kW, the cost of electricity is 0.124$/kWh and the payback period is 17 years.As compared with the reference system with the same methanol input and CO_2 capture rate,the hybrid system exhibits the advantage of reduced cost of electricity by up to 10.1%.