Optimization And Analysis On The Organic Rankine Cycle In Low-temperature

The waste heat resources is very abundant in our country,The current utilizationof waste heat in the high temperature of waste heat has mature technology,anddevelopment of low-temperature waste heat should be make fully used. In thetotal quantity of heat can be used, low temperature heat in approximately40%~50%,if this part can be make full use of, which will save a lot of resources for thesociety, and reduce carbon dioxide emissions and thermal pollution, this article willfocus on the low temperature waste heat power generation of Organic Rankinecycle(ORC) system in view of working medium optimization, structure optimization.First of all,the organic Rankine circulatory system model has been established inthis paper, the basic components include three part， the hot water circulation, thecooling water circulation and the working fluids cycle. Then choose the betterworking fluids,in view of the selected14kinds of pure substance, economicperformance evaluation is established with heat exchange area and output ratio;Aiming at evaluate the potential of working substance in ORC, establish heatrecovery efficiency evaluation; In a comprehensive consideration, combined with firstlaw, second law,economic performance and heat recovery four kinds of evaluationmethods,using the perspective of bi-level programming problem and the linearweighted function method,put forward the comprehensive performance evaluation,indifferent views of working fluids analyzed. In the analysis of the mixed workingmedium,by blending ratio and the evaporation temperature, analyzed the influence ofdifferent performance. In the view of economic,R123and R245fa objective functionvalue is relatively smaller than that of other working fluids, give a higher economicperformance; In the view of heat recovery efficiency, thermal efficiency is a functionof the critical temperature and for different working medium, working medium with alower critical temperature thermal efficiency is low,R1234ze give a betterperformance in heat recovery in the pure working medium,from the perspective of acomprehensive evaluation coefficient of the objective function value, all kinds ofworking medium increases with evaporation temperature changes are increase atfirst,then decreases,during the temperature from352k to357k. the comprehensive performance of R113and R227ea relatively better than other working medium. Thenfor low temperature waste heat power generation in the ORC system for structuraloptimization, such as add the intermediate heat exchanger (IHE),using smoke gas toheat and reheat cycle,etc.,and the efficiency, heat recovery,the view of thecomprehensive evaluation were used to analyze,and concluded that add the internalheat exchanger and extraction regenerative device will improve the performance ofthe system,and the reheater in the ORC system is not necessary,except improveeconomic performance in certain range,the other indexes fell.Finally,this article has carried on the experiment system design of3kw,partsselection,analysis,and in the accounting. the economic benefit of generating of150kwunit calculations was analysised.