Objective For the gasification station or gas filling station that uses LNG as the gas source, due to the current LNG unloading process, after the unloading of LNG tanker, there is still a certain amount of paid but unusable BOG in storage tank. In view of this common problem, an effective method for recovering BOG is studied.

Methods Taking a gasification station as an example, by calculating the recoverable BOG amount in the LNG tanker storage tank, combined with the recovered BOG state parameters, the unloading and operation process flow of the gasification station, the corresponding process transformation scheme is formulated.

Results The operation conditions of the main equipment to be selected are simulated. The state diagram of the exhaust capacity and power changing of the single-stage and two-stage compressors with time, and the state diagram of the BOG pressure and margin changing in the tanker with time are drawn. The efficiency of the equipment to be selected is compared visually.

Conclusions In the transformation scheme of LNG tanker BOG recovering process in the gasification station, the selection of two-stage low-temperature compressor can reduce the emission and the unloading loss of tanker effectively, which has more advantages.