A kind of production method of food-class liquid CO 2The present invention relates to the production method of a kind of production method of Liquid carbon dioxide, particularly a kind of food-class high-purity liquid CO 2.
The production method of Liquid carbon dioxide adopts three kinds of methods at home and abroad substantially: low-pressure process, middle-pressure process and high-pressure process.The main at present high-pressure process that adopts of China is 22～30 ℃ of normal temperature, liquefy under pressure 6.0MPa～9.0MPa condition, this method pressure height, the shipment of product needed high-pressure cylinder, labour intensity is big, liquefied fraction and production efficiency are low, and industrial scale can not maximize, and produce Liquid carbon dioxide per year and only are 2000～3000 tons; The middle-pressure process that adopts is that carbonic acid gas separates through washing, enter charcoal trap, enter the gas mixer again, compressed machine compression is boosted, and enters filtered through silica gel adsorber, molecular sieve adsorber and gas heater, enters liquefier and liquefied ammonia heat exchange at last, be cooled to-20～-25 ℃, enter the product storage tank, the quality product that this method is produced does not reach the requirement of using in welding, food and supercritical extraction field, mainly be impurity, water, sulphur deviate from not reach requirement.
The object of the present invention is to provide the production method of a kind of quality product height, food-class high-purity liquid CO 2 that efficient is high.
The present invention is achieved in that the production method of a kind of high purity food and Liquid carbon dioxide, it is characterized in that: it will separate through water separator successively from the carbonic acid gas of battery limit (BL), compressor rises to middle pressure, and the organosulfur convertor transforms, and desulfurizer desulfurization and active carbon adsorber take off impurity; The gas that comes out cools off through water cooler, enters water separator, enters molecular sieve purification device and fine filter then successively; Carbon dioxide after the filtration enters pre-cooler, liquefier, enters the Liquid carbon dioxide storage tank at last.
Aforementioned production method specifically is meant: from the carbonic acid gas of battery limit (BL), enter the carbonic acid gas water separator and separate saturation water, enter carbon dioxide compressor, gauge pressure adds to 2～2.5MPa, be warming up to 80～130 ℃, enter the organosulfur convertor then organosulfur is converted into inorganic sulfur, enter desulfurizer and active carbon adsorber again, organosulfur, inorganic sulfur and part moisture are fallen in absorption, make the sulfur-bearing total amount less than 0.1 milligram/cubic metre; The gas that comes out through water cooler be water-cooled to≤40 ℃, enter the carbonic acid gas water separator and separate saturation water, enter carbon dioxide molecule sieve cleaner and carbonic acid gas fine filter then, thoroughly unwatering, bacterium and peculiar smell make water＜10PPm; Carbon dioxide after the filtration enters the carbon dioxide precooling device and is chilled to-5～0 ℃ in advance, enters the co 2 liquefaction device, makes carbonic acid gas become liquid by gas, and its temperature is-19～-15 ℃, enters the Liquid carbon dioxide storage tank at last.
The rate of recovery height of product of the present invention; The disposable international food grade carbon-dioxide specification of quality that reaches of quality product, and can use in the special dimensions such as medicine, optics at welding, supercritical extraction; The scale of production method of the present invention can maximize, can reach the scale benefit, can reduce production costs; The product that this law is produced is convenient to transportation.
The invention will be further described below in conjunction with embodiment:
Embodiment: from the unstripped gas carbonic acid gas outside the battery limit (BL), its purity is 99.5%, and gauge pressure is 0.02MPa, temperature≤40 ℃, and flow is 1100Nm3/ h enters the carbonic acid gas water separator and separates saturation water, and compressed again machine rises gauge pressure to 2.5MPa, temperature rises to 100 ℃, pass through organosulfur convertor, desulfurizer, charcoal absorption groove successively, remove organosulfur and inorganic sulfur and other impurity, make the sulfur-bearing total amount less than 0.1 milligram/cubic metre; The gas that comes out is removed saturation water through watercooler and water separator, and temperature≤40 ℃ are passed through molecular sieve purification device, carbonic acid gas fine filter more successively, thoroughly unwatering (water＜10PPm), bacterium and peculiar smell; Carbon dioxide after the filtration is cooled to-5 ℃ through pre-cooler, is cooled to Liquid carbon dioxide through the co 2 liquefaction device again, and input Liquid carbon dioxide storage tank is stored, and the pressure of product liquid carbonic acid gas is 2.0MPa, and temperature is-16 ℃.
Products obtained therefrom detects through Sichuan Province Bureau of Technical Supervision gas products quality monitoring testing station, and product quality indicator is as follows:
Purity＞99.8% moisture:＜0.1%
Oil content: do not detect smell: free from extraneous odour
Acidity: meet the GB1917-94 standard
As seen, adopt the present invention can obtain meeting the food-grade carbon-dioxide national standard.