低温废气余热驱动有机朗肯循环的优化

PARAMETER OPTIMIZATION OF THE LOW-TEMPERATURE EXHAUST GAS WASTE HEAT POWERED ORGANIC RANKINE CYCLE

采用热力学关联式计算工质的蒸发压力、蒸发焓及液体比体积等热力性质,基于对废气余热驱动有机朗肯循环系统的分析,建立循环性能的预测方法。结合数学规划理论,建立有机朗肯循环的优化数学模型,以效率或净输出功率为目标函数,用内罚函数和黄金分割搜索优化算法对示例进行参数优化。结果表明,经优化后系统的输出功率增加近两倍。通过对影响循环热效率和效率主要参数的研究表明,有机朗肯循环的性能主要受工质的热物性、废气温度和比热容、蒸发器传热夹点温差及透平进汽温度的影响。

The exergy analysis of exhaust gas waste heat powerea ORC unit was penormed and an intuitive approach with simple impressions was proposed to calculate the performances the ORC unit. Parameter optimization was conducted with turbine inlet temperature simplified as the variable and exergy efficiency or power output as the objective function by means of penalty function and golden section searching algorithm based on the formulation of the optimization problem, the power generated by the optimized ORC unit can be nearly as twice as that generated by a conventional ORC unit. In addition, cycle parametric analysis was performed to examine the effects of thermo- dynamic parameters on the cycle performances such as thermal efficiency and exergy efficiency. It was proven that performance of ORC unit is mainly effected by the thermodynamic property of working fluid, the waste heat temper- ature, the pinch point temperature of the evaporator, the specific heat capacity Of the exhaust gas and the turbine inlet temperature under a given environment temperature.