Large temperature difference in high-pressure plate heat exchangers
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Our air separation unit has a capacity of 45,000 NM3/h. There are two types of gas flow in the high-pressure plate heat exchangers: one is where the gas goes from the second stage of the compressor to the expander at 2.7 MPa, and the other is where the gas comes from the third stage of the compressor at 7.2 MPa and then passes through a throttle valve before reaching the lower column. The return gases consist of oxygen at 8.2 MPa and contaminated nitrogen at 20 KPa. Each air separation unit is equipped with three sets of high-pressure plate heat exchangers. The facility has been in operation for three years now, and currently there is a significant difference in temperature across these three sets of heat exchangers, with the maximum temperature difference reaching 40 degrees; however, the dew point after heating and purging is within acceptable limits. I’m asking experts to explain what causes this.
Which company manufactures plate exchangers? It can handle such a high pressure difference.
Compare the piezoresistive values of previous channels on the board~~to see if they are normal ~~What about the liquid output? ~~
The temperature difference across the plates is large; from a process perspective, there is a high likelihood of blockages caused by ice or impurities. Additionally, too low a flow rate can lead to uneven flow. I’m not sure whether this issue has been resolved after heating the system. Also, where was the location selected for the dew point analysis? Was any analysis conducted on the high-pressure air before it entered the tower? With such a large device and such high gas flow rates during purging, it is difficult to detect minor ice blockages at the dew point
The heat exchangers have been in use for three years, and it’s time to schedule their cleaning; at least start with those that have the worst heat exchange performance.
It can be disassembled for manual cleaning or cleaned using chemical methods.
Hello, this is an imported plate heat exchanger that is brazed together as a single unit and cannot be disassembled; please suggest another solution
Hello, experts. This heat exchanger is imported, and the air separation equipment comes from Hangyang; it’s of the integrated brazed type. The dew points of the fluids at the inlet and outlet of the heat exchanger are all within acceptable limits, and there are no issues with the temperature probes. However, there is still a temperature deviation of 30 degrees. I would appreciate your advice
Hello, the heat exchanger has been heated, and the dew points at the inlets and outlets of all fluids are within the acceptable range of -55 degrees. Dew points were measured at both the inlets and outlets of each fluid; the high-pressure air entering the lower tower also passed the tests. The amount of purge gas used is between 190,000 and 200,000, and there is still a temperature difference of 30 degrees.