Binary Ice Vacuum Preparation Techniques

The binary ice is refers to (e.g. glycol) the mixture of water-soluble fluid and the ice crystal, it is the muddy suspending liquid, and usually is called the ice slurry, its fluidity is very good, and can be transported by the pump. In the ice making process, the heat transfer coefficient is high, while the heat transfer temperature difference is low. Compares with other medium, the cooling rate of binary ice is quick, and the cooling effect is good (unit mass binary ice contains 4-6 times of cold energy than that of cooled water and its cooling temperature is lower).If we use it in food cooling domain, it does not damage the product because its organization is soft, and if we apply the binary ice in cold storage air conditioning domain, it may realize the low temperature air supply of air-conditioning system, and the equipment installation is flexible and can adapt to the air conditioning load change well. Moreover, the binary ice can also be widely used in the domain of city centralized cooling, food engineering, sewage disposal, chemical industry, metallurgical industry, medicine, transportation engineering etc.At present, the binary ice making methods that are applied or studied are as follows: scraper type, direct contact type, vacuum type, falling film type, fluidized bed type .In which the vacuum type is high in efficiency, simple in structure, easy in operation, and the CFC or HCFC refrigerant may not be used in the binary ice preparation process if certain measures are taken, so it is one of the binary ice preparation method that has bloom future.In this article, the vacuum environment characteristic, including the hot molecular pressure effect, the gas molecular density fluctuation, the rarefied gas transmission phenomenon characteristic and so on has carried on from the shallow to the deep theoretical analysis, and the heat and mass transfer characteristic of material under low pressure has been discussed. Through the research on single bubble flash evaporation phenomenon, the binary ice vacuum preparation process mathematical model has been established. Through the model analysis, the flash evaporation process of different size bubbles as well as he binary ice forming process in vacuum flash vessel is estimated, and this model can also help us understand the factors related to ice formation rate and discuss the ice slurry making process through the injection water solution system takes in the vacuum flash vessel.Through combine the vacuum technology and the binary ice making technology together, this article has developed the binary ice vacuum preparation device, and has promoted the binary ice making technology.Test the influence of factors on the binary ice vacuum preparation, the factors of which are as follows: internal pressure of vacuum flash vaporization vessel, water supply flow-rate, and vaporization temperature of vapor condenser, additive and so on. And has carried on the analysis and the summary of the experimental result through the graphs and value computation software Matlab, after that, obtain the corresponding conclusion that can provide the scientific basis for the project application.