基于HYSYS的B型LNG燃料舱BOG压缩供给系统

Compressed BOG Supply System for Type B LNG Fuel Tank Based on HYSYS

以一艘B型液化天然气(Liquefied Natural Gas,LNG)燃料舱舱容为30000 m3的发电船为目标船,对其3种蒸发气(Boiled Off Gas,BOG)压缩供给系统进行模拟计算分析。采用HYSYS软件建立BOG压缩供给系统模型,通过实际气体状态方程计算BOG物性值,分别对该系统进行BOG温度、压力和流量单变量变化等方面的热力性能分析。结果表明当压缩机进口处选用高压力和低温度BOG时,能有效降低其功耗;常温BOG单级压缩机出口温度高于150℃,压缩机的选型受到限制;当常温BOG两级压缩机进口温度不超过2℃时,其出口温度不超过150℃;控制第二级压缩机进口温度可免设BOG冷却器,节约成本。

Three options of the compressed BOG(Boiled Off Gas)supply system for a power boat with type B LNG(Liquefied Natural Gas)fuel tank of 30000 m3 are studied through simulation.The system model is built with the software HYSYS.The physical properties of the BOG are calculated with the actual gas equation of state.The thermal performance of the system are analyzed against temperature,pressure and mass flow rate.The simulations show that the power consumption is noticeably lower under the condition of high BOG pressure and low BOG temperature at the inlet of the compressor.If the outlet temperature of a normal temperature BOG single-stage compressor is greater than 150℃,the choice list of the compressor is limited.The outlet temperature is no more than 150℃for a normal temperature BOG two-stage compressor when the inlet temperature keeps lower than 2℃.Therefore,controlling inlet temperature of the second stage compressor can save the investment for a BOG cooler.