System design and analysis on organic Rankin cycle for asphalt plant's waste heat recovery

Abstract

An organic Rankin cycle system was investigated with the purpose of utilizing the waste heat from the asphalt plant's rotary dryer. The factors that have the impact on the heat source properties by means of combustion and heat transfer were discussed. The ORC system was developed utilizing R245fa as the working fluid, in consideration of the operation conditions of the cycle and its environmentally-friendly characteristics. An evaporator which support phase-change heat transfer was chosen, because most of the energy is in latent heat of the vapour. A radial inflow turbine was selected due to the output power of the system. The operation data of the asphalt plant was taken to evaluate its potential of energy recovery. It can generate 104.4kW electricity when the ORC system is combined with JD3000 asphalt plant. If the electricity is used to the plant itself, 17.1% of electricity power could be saved. The scheme proposed could provide a new solution to the waste heat recovery of the asphalt plant.