Heat transfer performance of heat exchangers for the small air separation unit

The start-up phase of the whole low-pressure oxygen generator is that liquid empty appears first in the lower tower, and then liquid oxygen appears in the upper tower. The cold energy needed to accumulate liquid in the tower mainly comes from the expansion machine, which uses the low temperature gas after expansion to make part of the air liquefaction in the liquid purifier. But the upper tower itself can not produce liquid, it mainly depends on the liquid from the lower tower into the upper tower. In the phase of hydrops, in order to accumulate the liquid level as soon as possible, the cooling volume should be transferred to the tower as much as possible, the phenomena of overcooling, temperature difference at the hot end and cold loss increase caused by excess cooling of switching heat exchanger should be avoided. As for how to recycle and transfer the cold volume of the air expansion into the tower, whether it is by the liquid purifier to transfer the cold volume to the lower tow...

When the output pressure of turbine air compressor is constant, when the flow rate decreases to a certain value, surge will occur. Therefore, it is necessary to control the flow rate of the turbine air compressor and prevent its flow value from entering the surge zone. However, when the system resistance increases, the flow rate will surely decrease, which makes it possible for the flow value to enter the surge zone. Therefore, the common solution is to add a bypass valve from the outlet to the inlet or vent. When the turbine air compressor is normal, the valve is closed. The flow rate is reduced to a certain value, and then the flow through the turbine air compressor is increased.