Why cannot the temperature in front of the turbine expander be too low

A different approach should be adopted, that is, the temperature at the exit of the expander needs to match the saturation temperature at that pressure. The difference relative to this saturation temperature is called the \"superheat\" after the expander. The smaller this superheat, the lower the temperature, which is more conducive to the accumulation of liquid. This is the exact opposite of the concept of efficiency; therefore, in practice, focus is placed on using as little air as possible, with efficiency being a factor to consider only when there is an excess of cooling capacity. To be more specific, regarding your question: if the temperature at the inlet of the expander is too low, supersaturation may occur, resulting in liquid formation, which can cause damage to the impeller. Additionally, incomplete vaporization can also lead to pressure fluctuations in the expander. That said, it’s difficult to operate an expander with liquid in it using the standard process. For reference.

Simply put, it is to prevent liquid from entering the turbine inlet when the temperature is low, thereby avoiding damage to the equipment!