Method and equipment for dynamically recycling evaporated gas of liquefied natural gas

Abstract

The invention discloses a method and equipment for dynamically recycling evaporated gas of liquefied natural gas. The method includes firstly, monitoring density, temperature and pressure data of the evaporated gas of the liquefied natural gas stored in a storage tank; secondly, computing and preliminarily judging super-cooling quantities required by the liquefied natural gas stored in the storage tank according to the monitored data; thirdly, enabling propane media to be in refrigerating cycles and then inputting the super-cooling quantities into the liquefied natural gas stored in the storage tank via heat exchange; fourthly, enabling the liquefied natural gas in a super-cooling state to return the storage tank by means of circulation, enabling the liquefied natural gas in the storage tank to reach new super-cooling state balance, dissolving evaporated gas generated in the liquefied natural gas into the liquefied natural gas again and reducing evaporation quantities by 80%; fifthly, starting to execute the first step, the second step, the third step and the fourth step again when the evaporated gas of the liquefied natural gas stored in the storage tank is layered. The equipment comprises the liquefied natural gas storage tank, a low-temperature pump, a heat exchanger, a refrigerating plant, a sensor and a control device. The method and the equipment have the advantages that the evaporated gas of the liquefied natural gas can be dynamically recycled, and the equipment can run stably without being frequently started and stopped and is high in safety and low emission and operating cost.

Description

technical field [0001] The invention relates to a method and equipment for dynamically recovering liquefied natural gas evaporated gas. Background technique [0002] At present, coal and oil are the main energy consumption of human beings. In the primary energy consumption structure, coal accounts for 68.5%, oil accounts for 17.7%, and natural gas accounts for only 4.7%, which is far lower than the world average of 24%. This coal-based energy consumption structure will bury hidden dangers in the atmospheric environment. Liquefied natural gas (LNG) is the best storage form of natural gas. Under the current situation of increasingly stringent environmental protection requirements, for the technology-intensive LNG industry, the research and development of LNG-related technologies, especially LNG storage-related technologies, are of great importance to the development of the LNG industry. It has important social and economic benefits. [0003] LNG is usually stored in metal st...

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Problems solved by technology

[0005] The main purpose of the present invention is to solve the above-mentioned shortcomings existing in the existing liquefied natural gas vapor recovery method, and provide a dynamic recovery method and equipment for liquefied natural gas vapor, so that the dynamic recovery method of liquefied natural gas vapor has stable operation and does not require frequent It has the functions of start-stop, strong safety and low emission, and is not affected by changes in the external transport conditions of LNG boil-off gasification, greatly reducing operating costs

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