对流热采油页岩过程低温余热ORC系统热力分析  

Thermodynamic Analysis of a Low Temperature Waste Heat Organic Rankine Cycle System in the Process of the Convection Heat-based Oil Shale Exploitation

作　　者：杨新乐[1] 赵阳升[2] 冯增朝[2] 戴文智[1] 

机构地区：[1]辽宁工程技术大学机械工程学院,辽宁阜新123000 [2]太原理工大学采矿工艺研究所,山西太原030024

出　　处：《热能动力工程》2012年第6期664-669,735-736,共6页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金资助项目(50534030);国家自然科学青年基金资助项目(51104083)

摘　　要：为回收利用对流热采油页岩过程中产生的低温余热蒸汽,提出并设计有机朗肯循环(ORC)系统进行热力发电。在特定余热蒸汽参数条件下,基于R245fa循环工质,编制计算程序模拟分析了ORC系统变工况参数对该系统热效率及输出功率的影响规律。数值模拟结果表明:设定汽轮机背压为0.25MPa时,工质最高蒸发压力为2.566MPa,在此范围内,系统热效率随蒸发压力升高单调增加,增幅减缓;取蒸发器出口温度85℃时,对于不同的蒸发压力系统允许运行工质流量范围不同,在同一蒸发压力下,由于热源限制导致系统热效率并未随工质流量增加显著提高,但可得到更多输出净功;蒸发压力为1.5 MPa时,随余热排放温度的降低,系统输出净功显著提高;随汽轮机背压的降低,系统热效率得到明显改善,但汽轮机背压的降低增加了工质冷凝的困难,合适的背压值取0.2MPa。To recover the low temperature waste heat steam produced during the convection heat-based oil shale exploitation,presented and designed was an organic Rankine cycle system for power generation.Under the condition of specific waste heat steam parameters,based on the working medium R245fa for the cycle,a calculation program was prepared to simulate and analyze the law governing the influence of the off-design condition parameters of the ORC system on its thermal efficiency and output power.The numerical simulation results show that when the back pressure of the steam turbine is set at 0.25 MPa,the highest evaporation pressure of the working medium can reach 2.566 MPa.Within this range of the evaporation pressure,the thermal efficiency of the system will monotonically increase with an increase of the evaporation pressure.Under a same evaporation pressure,it will not increase obviously with an increase of the flow rate of the working medium,however,more net output power can be obtained.When the evaporation pressure is set 1.5 MPa,with a drop of the waste heat discharging temperature,the net output power of the system will increase markedly.With a drop of the back pressure of the steam turbine,the thermal efficiency of the system will be obviously improved.However,the drop of the back pressure of the steam turbine increases the difficulty for condensing the working medium and the proper back pressure is regarded as 0.2 MPa.

关 键 词：对流热采油页岩 低温余热蒸汽 ORC系统 热力分析 

分 类 号：TK11[动力工程及工程热物理—热能工程]