Refrigeration and temperature control systems play a key role in controlling microorganisms and extending the shelf life of many foods. Cryogenic refrigerants such as liquid nitrogen or carbon dioxide (CO2) are commonly used in the meat and poultry industry due to their ability to quickly and effectively lower and maintain food temperatures during processing, storage and transport. Carbon dioxide has traditionally been the refrigerant of choice due to its greater versatility and use in more refrigeration systems, but liquid nitrogen has grown in popularity in recent years.
Nitrogen is obtained from the air and is the main component, accounting for about 78%. An Air Separation Unit (ASU) is used to capture air from the atmosphere and then, through cooling and fractionation, to separate air molecules into nitrogen, oxygen and argon. The nitrogen is then liquefied and stored in specially designed cryogenic tanks at the customer’s site at -196°C and 2-4 barg. Because the main source of nitrogen is air and not other industrial production processes, supply disruptions are less likely. Unlike CO2, nitrogen only exists as a liquid or gas, which limits its versatility as it does not have a solid phase. Once the food is in direct contact, the liquid nitrogen also transfers its cooling power to the food so that it can be chilled or frozen without leaving any residue.
The choice of refrigerant used depends primarily on the type of cryogenic application, as well as the availability of a source and the price of liquid nitrogen or CO2, as this ultimately directly affects the cost of food refrigeration. Many food businesses are now also looking at their carbon footprints to understand how these factors affect their decision making. Other cost considerations include the capital cost of cryogenic equipment solutions and the infrastructure needed to isolate cryogenic piping networks, exhaust systems, and safe room monitoring equipment. Converting an existing cryogenic plant from one refrigerant to another requires additional costs because, in addition to replacing the safe room control unit to make it compatible with the refrigerant in use, the cryogenic piping often also has to be changed to match the pressure, flow, and insulation. requirements. It may also be necessary to upgrade the exhaust system in terms of increasing the diameter of the pipe and blower power. The total switching costs need to be assessed on a case-by-case basis to determine the economic feasibility of doing so.
Today, the use of liquid nitrogen or CO2 in the food industry is quite common, as many of Air Liquide’s cryogenic tunnels and ejectors are designed for use with both refrigerants. However, as a result of the global COVID pandemic, the market availability of CO2 has changed, mainly due to changes in the source of ethanol, so the food industry is increasingly interested in alternatives, such as a possible switch to liquid nitrogen.
For refrigeration and temperature control applications in mixer/agitator operations, the company designed the CRYO INJECTOR-CB3 to be easily retrofitted to any brand of OEM equipment, new or existing. The CRYO INJECTOR-CB3 can be easily converted from CO2 to nitrogen operation and vice versa by simply changing the injector insert on the mixer/mixer. The CRYO INJECTOR-CB3 is the injector of choice, especially for international faucet OEMs, due to its impressive cooling performance, hygienic design and overall performance. The injector is also easy to disassemble and reassemble for cleaning.
When CO2 is in short supply, CO2 dry ice equipment such as combo/portable coolers, snow corners, pellet mills, etc. cannot be converted to liquid nitrogen, so another type of cryogenic solution must be considered, often resulting in to another process. layout. ALTEC’s food experts will then need to evaluate the client’s current process and manufacturing parameters to recommend an alternative cryogenic installation using liquid nitrogen.
For example, the company has extensively tested the feasibility of replacing the dry ice CO2/portable cooler combination with the CRYO TUNNEL-FP1 using liquid nitrogen. The CRYO TUNNEL-FP1 has the same ability to efficiently cool large cuts of hot deboned meat through a simple reconfiguration process, making it easy to integrate the unit into a production line. In addition, the hygienic design CRYO TUNNEL-FP1 Cryo Tunnel has the necessary product clearance and improved conveyor support system to accommodate these types of large and heavy products, which many other brands of cryo tunnels simply do not have.
Whether you are concerned about product quality issues, lack of production capacity, lack of CO2 supply, or reducing your carbon footprint, Air Liquide’s food technologists team can help you by recommending the best refrigerant and cryogenic equipment solutions for your operation. Our wide range of cryogenic equipment is designed with hygiene and operational reliability in mind. Many Air Liquide solutions can be easily converted from one refrigerant to another to minimize the cost and inconvenience associated with replacing existing cryogenic equipment in the future.
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