低温余热蒸汽ORC发电系统热力性能实验研究

Experimental Study of the Thermal Performance of a Low Temperature Waste Heat Steam ORC Power Generation System

为了解矿藏热采过程低温余热ORC发电系统热力性能及其影响因素,搭建了低温余热蒸汽ORC热力发电实验系统,以5 kW背压式汽轮机为原动机,采用R11工质进行ORC热力性能测试实验。实验结果表明,110℃热源下,蒸发压力超过0.85 MPa后工质存在气液两相状态,提升至120℃后工质均为过热状态,增加热源温度可提高进入汽轮机的工质允许蒸发压力;汽轮机带电机运行后转速下降,在一定的热源温度下,汽轮机转速和相对内效率随蒸发压力的提升呈现不断增加的趋势,同时随热源温度上升,汽轮机转速增加,相对内效率提升;在不同的热源温度下,系统输出功率和热效率均随工质蒸发压力的提升而不断增加,最大输出功率达1.12 kW,热效率达4.92%,提升热源温度能够增加进入汽轮机工质过热度,提高系统的输出功率,但对系统热效率影响不大。

To obtain the thermal performance of a low temperature waste heat power generation system and its influencing factors,set up was a low temperature waste heat steam ORC thermal power generation test system. With a 5 kW back pressure steam turbine serving as the driving machine,R11 working medium was used to perform the ORC thermal performance testing experiment. The test results show that under a 110 ℃ heat source,when the steam pressure has exceeded 0. 85 MPa,the working medium exists in gas-liquid two phase state and when the temperature of the heat source has increased to 120 ℃,the working medium is in its superheated state. To rise the temperature of the heat source can increase the allowable evaporation pressure of the working medium admitted by the steam turbine and the rotation speed of the turbine will drop after it has driven the generator to run together. At a given temperature of the heat source,the rotation speed and relative inner efficiency of the steam turbine will both assume a continuously ascending tendency with a rise of the evaporation pressure and at the same time,the rotating speed of the steam turbine will go up and its relative inner thermal efficiency will rise with an increase of the temperature of the heat source. At various temperatures of the heat source,the output power and thermal efficiency of the system will all continuously increase with an increase of the evaporation pressure of the working medium,the maximal output power will reach 1. 12 kW and the thermal efficiency will hit 4. 92%. To increase the temperature of the heat source can increase the superheated degree of the working medium admitted by the steam turbine to enhance the output power of the system but have no big influence on the thermal efficiency of the system.