Deciphering why liquid nitrogen quick freezing is so popular

2021-02-03 10:23:27

      With the further improvement and development of liquid nitrogen quick freezing technology, liquid nitrogen quick freezing is quickly and widely used in fish, shrimp, crab, chicken, duck, meat (cattle, sheep, etc.), fruits (bayberry, lychee, etc.), vegetables, and All kinds of prepared foods (steak, sashimi, meatballs, fried shrimp, patties, hamburgers, pizzas, egg products, soups, etc.) are frozen.

    Liquid nitrogen is a colorless, odorless, low-viscosity transparent liquid with stable chemical properties. The boiling point of liquid nitrogen at normal pressure is -195.8°C. When it comes in contact with frozen food, the latent heat of evaporation that can be absorbed is 198.9kJ/kg; then the nitrogen vapor is heated to -20°C, and the average specific heat is 1.047kJ /(Kg·K), it can absorb 184.1kJ/kg. The total of the two items is 383.0kJ/kg, which is an ideal refrigerant. Quick-frozen food with liquid nitrogen, started in the United States. The United States began research in this area in the 1950s, and it was officially used in quick-frozen food in 1960. It was quickly promoted in production in 1964.

         In recent years, with the deepening of reform and opening up, major foreign multinational gas companies have competed to establish joint ventures in my country, bringing liquid nitrogen air separation equipment, technology and management, which greatly increased the production of cryogenic liquids in my country. And the scope continues to expand, and the price is greatly reduced (the price of liquid nitrogen has been reduced from about 2 yuan/kg to less than 1 yuan/kg), which greatly promotes the application of liquid nitrogen.