Production method of food grade liquid carbon dioxide product for recycling resurgent gases

Abstract

The invention relates to a carbon dioxide production method, and particularly discloses a production method of a food grade liquid carbon dioxide product for recycling resurgent gases, which comprises the following steps of: (1) compression process, (2) dealkylation process, (3) purification process, (4) liquefaction process, and (5) distillation and purification process, wherein in the purification process, an impurity heating desorbing step is used for heating the adsorbent, so impurities which are adsorbed by the adsorbent are heated to be desorbed, the adsorbent obtains adequate resurgent gas flow, and a cooling adsorbent step is used for cooling the adsorbent, and the gas flows return to the carbon dioxide raw gas which contains the impurities. Because of the production method of the food grade liquid carbon dioxide product, the contents of methane and ethylene in a food grade liquid carbon dioxide product are greatly reduced, and are lower than the international standard, meanwhile, the resurgent gases of a purification tower are recycled, so the utilization ratio of the carbon dioxide raw gases which contain the impurities is greatly improved and is improved to 88% from 76%, the yield of the food grade liquid carbon dioxide is increased, the production cost is reduced, and the emission of the greenhouse gases is greatly reduced.

Description

technical field [0001] The invention generally relates to a production method of carbon dioxide, in particular to a production method of a food-grade liquid carbon dioxide product that recovers regeneration gas. Background technique [0002] image 3 Show a kind of flow process of the production method of food-grade liquid carbon dioxide product, comprise the following steps: [0003] (1) Compression process 30 [0004] The carbon dioxide raw material gas containing mechanical water, methane, ethylene, benzene and other impurities with a carbon dioxide content of about 99.2% from outside the boundary area is washed with water and precooled by the precooler 10, and the mechanical water is removed by the first water separator 20 before entering In the compression process 30, the pressure is increased to 0.1-0.35Mpa by the first-stage compressor 31, the pressure is increased by the second-stage compressor 32 to 0.8-1.2MPa and the pressure is increased by the third-stage compre...

AI Technical Summary

Problems solved by technology

[0024] exist image 3 In the production method of the food-grade liquid carbon dioxide product shown, (2) ③ in the purification process 80 step of desorbing impurities by heating to make the impurities adsorbed by the adsorbent be heated and desorbed by the heated air flow used for desorption and (2) ④ in the purification process 80 In the step of cooling the adsorbent, the cooling air used to cool the adsorbent comes from the shell side of the heat exchanger 1012 on the upper part of the distillation purification tower 101 in the distillation purification process 100, which is throttled and expanded by the regulating valve 1014 and then depressurized to 0.05 MPa again. The gas mixture and the flash gas discharged from the spherical tank 112 are combined to form a confluent gas flow. The confluent gas flow is emptied after ③ heating and desorbing impurities step and ④ cooling adsorbent step. However, the evacuated gas contains a large amount of carbon dioxide, which not only causes a huge waste of raw gas, but also emits a large amount of greenhouse gases into the atmosphere

[0025] In addition, in image 3 In the production method of the food-grade liquid carbon dioxide product shown, the purification process 80 is carried out after the three-stage compression of the compression process 30, and the outlet pressure of the three-stage compressor 33 is as high as 2.3-2.8MPa, which makes the equipment in the purification process 80 , Instruments, pipelines and adsorbents all work under relatively high pressure. The high pressure resistance level proposed for these equipment, instruments, pipelines and adsorbents increases cost investment, reduces service life, and increases safety hazards.

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