A process system for extracting helium by using the tail gas of lng plant

Abstract

A process system for extracting helium by using the tail gas of an LNG plant, including a helium purification tower, which is equipped with a piston type membrane separation device, a palladium membrane dehydrogenation device, an external circulation extraction device, a heat exchange device and a refrigeration unit. Separation and purification device, the piston type membrane separation device is set above the palladium membrane dehydrogenation device, the heat exchange device and refrigeration separation and purification device are set under the palladium membrane dehydrogenation device, the tail gas of the LNG plant is connected to the top inlet of the piston type membrane separation device, the piston The bottom outlet of the type membrane separation device is connected to the top inlet of the palladium membrane dehydrogenation device, and the bottom outlet of the palladium membrane dehydrogenation device is connected to the inlet of the refrigeration separation and purification device through a heat exchange device. The invention uses the high-pressure tail gas of the LNG plant as the gas source input of the equipment, saves the pre-pressurization equipment, effectively maintains the low-temperature state of the high-pressure tail gas of the LNG plant, reduces costs, and the gas ratio in the high-pressure tail gas is stable, and the content of helium and methane is relatively constant , Low energy consumption per unit of helium production.

Description

technical field [0001] The invention belongs to the technical field of industrial production of helium, and in particular relates to a process system for extracting helium by utilizing tail gas of an LNG plant. Background technique [0002] Helium is a colorless, odorless, non-flammable inert gas with an extremely low content of about 5.2 parts per million (5.2ppm) in the air. It is the substance with the lowest critical temperature found by human beings. Its melting point is 272.2°C (under 25 atmospheres), the boiling point is -268.9°C, and the density is only 0.1785g / L. Helium is a single-atom element molecule, there is no stable compound, and it is insoluble in water. [0003] Helium is one of the rare strategic materials indispensable for the development of national defense industry and high-tech industry. Helium plays an irreplaceable role in medical, military, refrigeration, semiconductor, pipeline leak detection, high-precision welding, metal manufacturing, deep-sea ...

AI Technical Summary

Problems solved by technology

[0007] In order to solve the deficiencies in the prior art, the present invention provides a process system for extracting helium by utilizing tail gas of LNG plants, which basically does not generate waste gas, has low energy consumption and high purity of extracted helium

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