LNG (liquefied natural gas) loading and unloading system and unloading method thereof

Abstract

The invention provides an LNG (liquefied natural gas) loading and unloading system and an unloading method thereof. The system comprises an LNG loading header, an LNG loading pipeline, a BOG return arm, a BOG return pipeline, a BOG return header, an LNG unloading pipeline, an LNG unloading header, a high-pressure natural gas inlet pipeline and a high-pressure natural gas inlet header. During unloading, a hand valve of a loading and unloading arm is opened, and the loading and unloading arm is pre-cooled by use of the LNG on a tank car; after pre-cooling, a hand valve of the BOG return arm is opened, the tank car can be boosted by use of high-pressure natural gas, and the LNG on the tank car can be unloaded to an LNG storage tank. High-pressure natural gas boosted unloading is adopted, theoperation process is simple, all that is required is to complete pre-cooling of the loading and unloading arm, the pre-cooling time is short, and the unloading efficiency is improved; besides, the system is slightly affected by the environment temperature and can smoothly complete unloading when the environment temperature is lower, and the defect of poor environment adaptability of a self-boostedunloading system is overcome.

Description

technical field [0001] The invention relates to a liquefied natural gas loading and unloading vehicle system and a vehicle unloading method. Background technique [0002] Liquefied natural gas (LNG, liquefied natural gas) is a widely used high-quality energy, which has the characteristics of high calorific value, high efficiency and low pollution. Loading and unloading systems and corresponding facilities are usually installed in the LNG emergency reserve peak-shaving station, and the LNG unloading system and facilities are all unloaded by air-temperature vaporizer gasification and tank car self-pressurization. [0003] The self-pressurized unloading process of the air-temperature gasifier is complex, with many flange connections, purging replacement, and slow pre-cooling rate. Each pre-cooling needs to be controlled at about 20-30 minutes, otherwise it is easy to generate excessive stress and cause flange leakage; [0004] The air-temperature vaporizer is greatly affected...

AI Technical Summary

Problems solved by technology

[0004] The air-temperature vaporizer is greatly affected by the ambient temperature, especially in winter or in extreme weather, the air-temperature vaporizer is prone to frost or ice, which will significantly reduce the heat transfer effect and self-pressurization rate of the vaporizer, and affect the LNG The gas phase pressure of the tank car reduces the unloading speed and increases the unloading time;

[0005] In addition, under the same unloading scale, more unloading systems need to be installed, which increases equipment, pipelines and other process facilities, resulting in high project investment, large floor area, and low utilization rate of land resources. Mouth Leakage Risk

Therefore, using air-temperature gasifier gasification and tank car self-pressurization method to unload trucks has poor environmental adaptability, complicated operation process, long operation time, large land occupation and high investment

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