Cooling of cryogenic reactors
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A cryogenic reactor, 12 m3, with a jacket and internal coils, requiring a temperature of -40°C. Should one choose a low-temperature heat transfer oil unit or liquid nitrogen? Please share your respective strengths and weaknesses.
Select the refrigeration unit; medium: ethylene glycol
Consider the cooling requirements: if a rapid cooling rate is required, liquid nitrogen is recommended; if the requirements are not stringent, ethylene glycol or heat transfer oil is suggested； If further heating is needed, it’s best to use heat transfer oil.
When using liquid nitrogen, the material must possess both low-temperature resistance and corrosion resistance~~~ In that case, a chromium-nickel alloy is the only option~~~ However, an advantage of this alloy is that it allows for a smaller size. Ethylene glycol is the recommended coolant~~~
Our company’s Air Liquide Alaska unit for cryogenic applications – liquid nitrogen for cooling the heat transfer oil
Why not use liquid nitrogen for direct cooling, but instead cool the heat transfer oil with liquid nitrogen and achieve indirect cooling?
Have you considered that when liquid nitrogen vaporizes inside the coil, if its flow rate is too high, the volume of gas generated will be large. Given the small diameter of the coil, the gas flow velocity will be very high, which can easily carry the liquid nitrogen into the discharge pipe. As a result, there are limits on the amount of liquid nitrogen that can be added, and therefore the cooling time may not be much faster than that achieved with heat transfer oil.
Have you considered that when liquid nitrogen vaporizes inside the coil, if its flow rate is too high, the volume of gas generated will be large. Given the small diameter of the coil, the gas flow velocity will be very high, which can easily carry the liquid nitrogen into the discharge pipe. As a result, there are limits on the amount of liquid nitrogen that can be added, and therefore the cooling time may not be much faster than that achieved with heat transfer oil.
At liquid nitrogen temperatures, the material freezes into ice, making it impossible to maintain stability. Using alcohol for circulation is relatively stable and easy to control