Critical Review of Hybrid Power Cycles Part 2:Using thermochemical upgrading

摘要

Most power generation systems use one source of heat,say fossil fuel,nuclear,solar,or geothermal,at one temperature,and also use that heat source directly as thermal energy.In cases where the cost of the heat is related to the temperature,such as with solar collectors,or when the temperature of the heat source is limited by operational considerations,such as in nuclear reactors,or when the available temperature is well below technological limitations of the plant,such as in geothermal energy use,or when waste heat at appropriate temperatures and price is available,such as in compounded internal combustion engines,it was found that gains in efficiency and reductions of emissions and cost could be achieved by using multiple heat sources of different temperatures,as described in part 1 of this paper [1].This paper is a critical review of another type of hybridization of power systems,called thermochemical energy conversion,by using some or all of the added thermal energy to produce a fuel,which is then burned for heat,and in some cases thus raising the power plants efficiency and/or reducing emissions,especially of CO2,and very importantly,allowing energy storage and distribution in the form of hydrocarbon fuels.Thus conversion to fuel alleviates some of the significant problems associated with the intermittency of heat sources such as solar.This paper focuses on the hybrid solar thermochemical power generation systems,which are believed to be economically more competent than the solar alone based power systems.