When the main condenser evaporator leaks seriously, a large amount of high-pressure nitrogen will leak to the low-pressure oxygen side, and the pressure of the upper and lower columns and the purity of the product will change significantly until normal production cannot be maintained.
When the main condenser evaporator leaks slightly, the pressure of the upper and lower columns will not change significantly, and the purity of liquid oxygen in the main condenser evaporator will not decrease significantly. The common phenomenon is that the purity of the gas and liquid oxygen in the main condensing evaporator is very different, and the gas concentration is lower than that in equilibrium with liquid oxygen. For example, the concentration of liquid oxygen is 99% and that of gaseous oxygen is 96%, that 7 main cooling pipes were found to be leaking during maintenance.
The common causes of leakage are as follows:
1.Pipes are worn due to mutual vibration. For long tube condensing evaporator, there are thousands of copper tubes, the diameter of which is only 10 mm, the length of which is 8m, and the distance between the tubes is very small. In the process of operation, due to the impact and vibration of the air flow, it is easy to bend and deform in the middle of the pipe and rub against each other, and may wear for a long time.
2.The water in the pipe causes freezing and cracking. When the heating is not complete, especially when the small tubes are blocked, the chance of water accumulation will be formed, and it can not be blown away in the heating process. The water will freeze into ice at low temperature, and the volume will expand, which may cause the small pipe to freeze and crack.
3.The main condensing evaporator has a slight explosion in local area. When acetylene or hydrocarbons accumulate locally in the main cooler, explosion may occur under certain conditions. When such a slight explosion occurs, there is no external reaction, no sound can be heard, and it is usually undetectable at first. Only when the oxygen purity changes automatically and cannot be adjusted,can this situationhappen.
