After the distillation column is started, the main possible reasons why the high pressure does not rise to the designed value are:
1) insufficient processing air volume;
2) serious leakage of inlet and exhaust valves of the expansion machine;
3) leakage from high pressure to low pressure. What on earth is the specific reason, should be checked before judgment. The rough introduction is as follows:
First, determine whether the air displacement of the air compressor meets the design requirements. Judging from the discharge of oxygen, nitrogen and distillation, when the low pressure (surface pressure) is kept at 0.055MPa, the pressure difference of general oxygen flow meter is above 6.23kPa (40cmCCl4 column, nitrogen flow rate is above 5.46kPa (35cmCCl4 column), and distillation is above 16kPa (12 cm mercury. It shows that the air volume meets the design requirements.
Otherwise, check:
1) the pipe line, purifier import valve, air compressor at all levels chui chu fa, oil-water separator chui chu fa whether leak;
2) Check whether the air filter is blocked;
3) whether the air compressor valve is damaged or not;
4) whether the cylinder and piston ring are worn;
5) If the air volume is sufficient, check whether the middle and low pressure of the distillation column are too high;
6) If the medium pressure is obviously greater than the normal value, the sealing condition of the inlet and exhaust valves of the expansion machine should be checked.
The method of checking the sealing of the expansion machine valve: close the joint-1 valve and the through-6 valve, drain out the medium pressure gas, and close the air inlet valve of the expansion machine. Open the-6 valve slowly. When the high pressure reaches 2MPa, open the outlet pressure gauge joint of the expansion machine and check whether there is air leakage. If the air inlet valve is good, close the pass-6 valve, open the blowing-off valve of the expansion machine, release the air storage, and then put the air inlet valve of the expansion machine in the state of rising and opening, and the exhaust valve in the state of closing. Open the-6 valve slowly, raise the high pressure to 2MPa (gauge pressure), and check whether the outlet pressure gauge joint of the expansion machine leaks. If the inlet and outlet valves leak, they should be disassembled for maintenance.
If both the inlet and exhaust valves of the expansion machine are in good condition, it is necessary to check whether the tube of the heat exchanger is cracked. The inspection method is to close all the valves of the distillation column and open the high pressure air inlet valve. Raise the high pressure air pressure to the working pressure when the equipment is started, and check whether there is gas in the low pressure system. If there is gas, it means the possibility of leakage from high pressure to low pressure, then further determine the leakage position and repair it.
