Equipment and process for purifying helium from BOG gas

Abstract

The invention discloses equipment and process for purifying helium from BOG gas. The invention relates to the field of BOG gas helium purification. The equipment comprises a primary catalytic dehydrogenation reactor, a cooler, a molecular sieve dryer, a feed gas compressor, a heat exchanger, a membrane separator and a vacuum pump, hydrogen in the helium purification process is reduced by adoptinga three-stage catalytic dehydrogenation reaction, the physical properties of hydrogen and helium are very close, therefore, the hydrogen in the pure helium cannot be removed by using a pressure swingadsorption or cryogenic process, multi-stage catalytic dehydrogenation ensures the purity of helium, a membrane separation process is adopted, BOG gas of the raw materials is concentrated by 30 times,the treatment capacity of the subsequent helium purification process is reduced, the permeability coefficient of gas molecules is increased by adopting a mode of pressurizing before the membrane andvacuumizing after the membrane, helium reaches higher yield and purity by using a smaller membrane area, the recovery rate of helium is increased by returning the desorbed gas of the helium purifier to the front of the feed gas compressor, and the helium yield of the whole device is as high as 99%.

Description

technical field [0001] The invention relates to the field of helium purification by BOG gas, in particular to a device and a process for purifying helium by BOG gas. Background technique [0002] Due to its low density, low boiling point and inert properties, helium is widely used in aerospace, refrigeration, medical, optical fiber, leak detection, deep-sea diving, high-precision welding production and other fields. Especially at the space launch site, in the space launch project using liquid hydrogen / liquid oxygen as fuel, due to the low boiling point and safety of helium, it is widely used in pipeline safety replacement, rocket storage tank safety replacement and flight process There is currently no other product that can replace the function of helium for the pressurization of the rocket tank and the safe blowing of some low-temperature components. [0003] Helium is a product of radioactive decay and is only present in relatively high concentrations in a small fraction ...

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Problems solved by technology

[0005] However, in the BOG helium extraction cryogenic process, with the continuous decrease of refrigeration temperature, the energy consumption per unit of refrigeration capacity has increased sharply, and higher and more stringent requirements have been put forward for the design, manufacture and operation of equipment. Natural gas is a multi-component mixture , Low-temperature phase equilibrium is the basis for cryogenic helium extraction of natural gas. Due to the limitation of the freezing point and solubility of substances, as the refrigeration temperature decreases, more substances will cause low-temperature blockage. The enrichment and concentration of trace hydrogen in natural gas make the high-purity of helium restricted

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