Method and device for united production of industrial level and food level liquid carbon dioxide

Abstract

The invention discloses a method and a device for the united production of industrial level and food level liquid carbon dioxide, which is suitable for a concentrated occasion of carbon dioxide. The method comprises the following steps: carbon dioxide raw material gas after being pressurized is desulfurized, dewatered, dried and processed, non-condensable gas is separated after precooling and low-temperature liquefaction, and one part of liquid carbon dioxide is purified and supercooled to obtain an industrial level liquid carbon dioxide product; a food level liquid carbon dioxide product is obtained after precooling, hydrocarbon removal, purifying, cooling, drying, low-temperature liquefaction and extraction are carried out on the other part of liquid carbon dioxide. The device realizing the method comprises a pipe opening, a compressor, a devulcanizer, a dryer, a precooler, a condenser, a separator, a purifying tower, a supercooling device, a storage tank, a hydrocarbon removal tower, a heat exchanger, a cooler and the like which are sequentially communicated. The invention has the advantages of advanced process technology, full energy utilization, little energy consumption, low production cost, high production efficiency, little equipment investment, stable product quality, and the like.

Description

technical field [0001] The invention relates to a co-production method and device for industrial-grade and food-grade liquid carbon dioxide, which is suitable for the occasion of enrichment of carbon dioxide, especially suitable for the process of using coal as raw material to produce synthetic ammonia, methanol or hydrogen, decarbonization and venting by pressure swing adsorption In the case of medium concentration carbon dioxide gas. Background technique [0002] In the process of producing synthetic ammonia, methanol or hydrogen with coal as raw material, the content of carbon dioxide in the carbon dioxide gas vented by pressure swing adsorption decarbonization is generally 70% to 90%, and its concentration is low. Among them, hydrogen, carbon monoxide, nitrogen, sulfide and methane, ethane, benzene and other hydrocarbon impurities are relatively high. The process of directly preparing food-grade liquid carbon dioxide with this carbon dioxide raw material gas is complica...

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Problems solved by technology

The process of directly preparing food-grade liquid carbon dioxide with this carbon dioxide raw material gas is complicated. If oxygen or air is added for catalytic oxidation, due to the high combustible components, the amount of oxygen or air added is large, the energy consumption is large, and the utilization rate of effective gas is low. , leading to high operating costs; and the content of hydrogen and carbon monoxide is not stable, and the operation control is very troublesome

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