小型BOG再液化系统流程参数分析及优化

Process parameter analysis and optimization of small BOG re-liquefaction system

混合冷剂再液化系统回收液化天然气(LNG)加气站产生的蒸发气(BOG)是一种节能环保的新方法。为回收偏远地区小型LNG加气站现场储罐产生的BOG,以某LNG加气站实际情况为例,提出了一种小型带预冷的混合冷剂制冷循环回收加气站产生的BOG。对流程中压缩机进出口压力、分离温度以及混合工质循环流量等参数进行了模拟分析,探究了参数对系统能耗的影响及规律。在此基础上,以压缩机总功耗为目标函数,换热器最小换热温差等为约束条件,对该方法进行了优化。结果表明,在保证BOG液化率不变的情况下,优化后的制冷循环BOG直接再液化总功耗为9.37 kW,相比于优化前能耗下降了7.5%,优化效果理想。

The mixed refrigerant re-liquefaction system recovers the boil-off gas(BOG)produced by the liquefied natural gas(LNG)filling station is a new way of energy saving and environmental protection.In order to recover the BOG generated by the on-site storage tank of a small LNG refueling station in a remote area,taking the actual situation of a LNG refueling station as an example,a small-scale mixed refrigerant refrigeration cycle with precooling was proposed to recover the BOG generated by the filling station.The parameters of the inlet and outlet pressure of the compressor,separation temperature and mixed working fluid circulation flow rate in the process were simulated and analyzed,and the influence and law of parameters on the system energy consumption were explored.On this basis,taking the total power consumption of the compressor as the objective function and the minimum heat exchange temperature difference of the heat exchanger as the constraints,the method was optimized.The results show that under the condition that the BOG liquefaction rate remains unchanged,the total power consumption of the optimized refrigeration cycle BOG direct reliquefaction is 9.37 kW,which is 7.5%lower than the energy consumption before optimization,and the optimization effect is ideal.