炼油厂低温余热有机朗肯循环工艺参数选择

ORC process parameters selection of refinery low-temperature waste heat

炼油厂低温余热具有热量大、取热方便等特点,适合采用有机朗肯循环发电方式进行回收利用。从工程设计角度看,膨胀机型式、工质类型和最佳蒸发温度等参数是确定工艺方案时的重点参数。根据炼油厂低温余热参数进行热力计算,对重点参数进行比选,即可得出不同热源条件下的最优工艺参数。研究表明,向心式膨胀机适用于热源热量较大的场合,单机功率可达500~10000kW,螺杆式膨胀机适合于小流量、小膨胀比、单机功率100~1000kW的场合;循环工质R600、R600a和R245fa在热源温度90~130℃区间内的热力性能相近,热源温度较高时R245fa的热力性能更好,选择工质时应着重考虑系统配套措施和工质价格因素,工质价格对大容量系统一次投资影响较大;系统温差和冷热源温度确定后,即可通过模拟计算得出其佳蒸发温度,热源温度为130、120、110、100、90℃时,系统的最佳蒸发温度分别在85、80、75、70、65℃附近。

Refinery＇s low-temperature waste heat has the characteristics of large quantity and convenient to use, it is suitable for recycling by organic Rankine cycle power generation. From the perspective of Engineering designing, key parameters for determining process plan include expander model, working fluid type and optimum evaporation temperature. The thermal calculation based on the parameters of refinery low-temperature waste heat and the selection of key parameters would get optimal process parameters under different heat source conditions. Research shows that centripetal expander is suitable for larger heat sources, it＇s single machine power should be 500 to 10000 kW; Screw expander is suitable for condition with small flow rate and small expansion ratio, its single machine power is between 100 to 1000 kW. Working fluids R600, R600a and R245fa have similar thermal performance, various factors especially the price and System facilities should be considered when selecting working fluids. Different heat source temperature has its optimum evaporation pressure, when the heat source temperatures are 130/120/110/100/90℃, the corresponding optimum evaporation pressures are 85/80/75/70/65℃.