CNOOC Gas & Power Group applies for a patent for a zero-emission BOG replacement system for storage tanks in new LNG receiving stations

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**According to information from the Intellectual Property Office, CNOOC Gas & Power Group Co., Ltd. filed a patent application titled “A New Type of BOG Displacement Zero-Emission System for Storage Tanks in LNG Receivers and Its Implementation Method”, with the publication number CN121474489A; the application was submitted in November 2025. The patent abstract indicates that the present invention relates to a new zero-emission BOG displacement system for storage tanks in LNG receiving stations, along with the methods for implementing it. Based on the existing design of LNG receiving stations, without altering the layout of their equipment and facilities, this method is used to carry out BOG displacement. The natural gas in the high-pressure transmission pipeline is returned to the BOG pipeline of the LNG storage tank via a throttling expansion device on the high-pressure make-up pipeline, and the natural gas after throttling expansion and pressure reduction is introduced into the LNG storage tank from the top of the tank. The gas inside the tank is pumped from the bottom of the tank through the pump cylinder by a low-pressure pump, and then discharged outward through the vent valve on the pipeline connected to the pump cylinder. At the same time, low-temperature BOG gas is introduced into the unloading pipeline; it then enters the storage tank via this pipeline as well as the inlet and spray lines. Once pre-cooling of the storage tank’s unloading pipeline is completed, this flow path is shut off ； Its displacement process is simple and easy to operate, with significant energy-saving effects.