Abstract
A huge amount of low temperature waste heat is wasted in refineries. Organic Rankine cycle (ORC) is an effective way to generate power from recovered heat. The Pinch point between the heat carrier and the working fluid limits the amount of heat transferred from the waste heat carrier to the working fluid, which affects the power output directly. For ORC without superheating, the Pinch point would appear at two possible positions, the start point of preheating, namely Preheating Pinch Point (PPP), or the start point of vaporization, namely Vaporization Pinch Point (VPP). In this paper, factors are analyzed, which may influence the Pinch position, including the heat capacity flow rate of waste heat carrier; waste heat inlet temperature, evaporation temperature, the ratio of latent heat to sensible heat of working fluid. A mathematical model including above parameters is deduced, which can not only predict the Pinch position accurately and calculate the heat recovered easily, but also find out the proper way to increase the amount of heat recovered.
