Method for producing food level liquid carbon dioxide product

Abstract

The invention relates to a method for producing edible liquid carbon dioxide product, characterized in that in compression step, the distribution of the third-stage outlet gas of compressor is adjusted by an adjusting valve, to supply needed thermal source to distillation via the compressed gas transmitted to a purifying tower, in the purifying step, some carbon dioxide gas and foul gas of purifying tower are discharge from tower top as splash steam to be throttled, expanded and reduced temperature via an adjusting valve A, to be feedback to a heat exchanger at the upper part of the purifying tower, to exchange heat with ascending splash steam in tube, and reduce pressure to 0.05MPa via an adjusting valve B, to be feed into purifying process to exchange heat with material gas to recycle cold as the regenerated gas of purifying or drying process. The invention uses adjusting valves A, B to control pressure discharge of purifying tower, to assure the stable pressure of purifying tower. The recycle rate of carbon dioxide of invention is at least improved 3%, while the consumption is at least reduced 5% and the carbon dioxide can reach the standard of edible carbon dioxide.

Description

technical field [0001] The invention relates to a production method of a food-grade liquid carbon dioxide product. Background technique [0002] Carbon dioxide is an important raw material for industrial production, widely used in metallurgy, iron and steel, petroleum, chemical industry, electronics, food, medical treatment and other fields, especially in food industry applications, such as modified atmosphere preservation of food, beverage industry applications, Food refrigeration and freezing applications, supercritical extraction, etc. There are two types of carbon dioxide-rich gas sources available for industrial recovery, namely natural carbon dioxide gas source and industrial by-product gas source carbon dioxide. Natural carbon dioxide gas is produced in some natural gas fields. Carbon dioxide-rich gas fields have a carbon dioxide content of 15-99%. In Guangdong, Shandong, Jiangsu and other places in China, there are high-concentration carbon dioxide gas fields with ...

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Problems solved by technology

Patent No. 00116187.3 introduces a production method of food-grade liquid carbon dioxide. The production process includes raw material gas compression, desulfurization and other purification processes, drying, liquefaction and other processes. The liquefied carbon dioxide directly enters the product storage tank. Through this method, certain Purity of liquid carbon dioxide, but due to insufficient and effective removal of N that may exist in the feed gas 2 、H 2 、CH 4 These components belong to light components, are not easy to liquefy, and can be dissolved in a certain amount of liquid carbon dioxide, which affects the quality of the product carbon dioxide. At the same time, the invention does not fully recover the cooling capacity in the process, resulting in relatively high energy consumption. Large, does not meet the current development ideas of energy saving and circular economy; application number 200610092071.4 introduces a method of absorbing carbon dioxide with potash-alkaline compound solution, and then desorbing it to produce carbon dioxide from the absorption solution. The recovery rate of this method is not high At the same time, it has the disadvantages of easy loss of absorption liquid, secondary pollution, and high energy consumption.

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