Application Of Heat Pipe Heater In Organic Rankine Circulation System

The amount of flue gas waste heat is large, the potential and economic value of recycling is huge, Organic Rankine Cycle (ORC) has an advantage in Mid-and-low temperature thermal energy within 300℃, and it is very suitable for our country flue gas heat recovery, which has received more and more attention of scholars around the world, they carried out a number of related research, however, less research for low temperature corrosion with ORC system, which is the major problem for the use of flue gas, therefore, in order to solve the problem, This paper presents ideas that combine the heat pipe heat exchanger with ORC technology. The main research contents are as follows:(1) Based on evaporation parameters method and the first law of thermodynamics, presents analysis on the selection of optimum working fluid and the thermal Performance. The results show that:R123 has a higher cycle thermal efficiency than R245fa with the same evaporation parameters, in addition R123 has lower vapor pressure evaporate under the same temperature, considering system performance and environmental safety, currently R123 is better than R245fa. There exists an optimal pumping pressure corresponding to a maximum system thermal efficiency, when the evaporation pressure is greater, the ratio of pumping pressure and the evaporation pressure is smaller.(2) Analyzed low Temperature Corrosion and the calculation of flue gas acid dew point temperature. In order to avoid low temperature corrosion, we must comply with two technical routes:improve the outlet temperature of flue gas temperature and the inlet temperature of cold fluid, reduce heat transfer resistance of flue gas, at last I suggest the semi-empirical formula proposed by Wang Ji Biao for bituminous coal flue gas acid dew point temperature.(3) Designed and calculated heat pipe preheater. It is found:the thermal conductivity of organic working fluid is low, its heat transfer coefficient of the light pipe is not very high, we can make the heat transfer coefficient of flue gas bigger by installing appropriate fins on the flue gas side, ORC system is easy to avoid low temperature corrosion.(4) Launched a fin structure optimization in the evaporation Part of heat pipes. The fins exist two effects of diversion and enhanced disturbance, the diversion will weaken the heat transfer, which is stronger than the disturbance enhanced fin heat transfer enhancement, increasing heat transfer area is the innate character of heat transfer enhancement with fins, the design and optimization of fin structure should be focus on the remission of diversion effect as well as the expansion of heat transfer area.