耦合甲醇重整制氢的新型冷热电联供系统4E分析

4E analysis on novel CCHP system integrated with steam reforming of methanol

为了充分利用内燃机余热,提出一种利用甲醇重整制氢和吸收式制冷装置依次回收内燃机烟气余热的新型天然气冷热电联供(CCHP)系统.通过建立系统的热力学模型,对其进行能效、效率、经济和环境(4E)研究,并分析关键参数对系统性能的影响.研究结果表明,该联供系统在给定工况下可同时向用户提供47.40、235.57和228.89kW的冷、热、电负荷,系统的总能效和效率分别为80.21%和41.71%,损失最大的部件依次是内燃机、反应器和质子交换膜燃料电池(PEMFC);系统总成本为439.43元/h,其中环境成本占比3.2%.在研究的参数范围内,增加天然气与甲醇流率、提高重整反应温度与PEMFC工作压力或减少冷却水流率均可提高联供系统的效率,提高重整反应温度,降低天然气与甲醇流率和PEMFC工作压力均可减少系统总成本.

To make full use of the waste heat of internal combustion engine(ICE),a novel natural gas based combined cooling,heating and power(CCHP)system was proposed,in which the heat of exhaust was absorbed by the steam reforming of methanol(SRM)and absorption chiller in turn.The thermodynamic model was established to identify the energy,exergy,economic,and environmental(4 E)performance of the system,and the influences of the key parameters on the system performances were analyzed.The results show that under the design conditions,the system can simultaneously supply users with cooling,heating and electricity loads of 47.40,235.57 and 228.89 kW,respectively.The overall energy and exergy efficiencies of the system are 80.21%and 41.71%and the top three components of exergy destruction are ICE,reactor and proton exchange membrane fuel cell(PEMFC).The total cost of the system is 439.43 yuan/h with the environmental cost being 3.2%.In the study ranges of parameters,the system exergy efficiencies can be improved by increasing natural gas flow and methanol flow rates,enhancing reaction temperature of SRM and working pressure of PEMFC,or reducing the cooling water flow rate.The system total cost can be reduced by enhancing reaction temperature of SRM or decreasing natural gas and methanol flow rates and working pressure of PEMFC.