How to blow off the distillation column of small air separation equipment?

 The purpose of blowing off the rectification tower after heating is to remove mechanical impurities in pipes and containers. The steps for blowing out are as follows:
    1) Preparation before blowing: Close the heating air main inlet valve and all heating valves, open the purifier oil-water separator blowing valve at the same time, relax the top rod of the inlet and exhaust valves of the expander, close the -6 valve, Pull open the valve stem of the section-1 valve, open the blow-1, blow-2 valves and high pressure gauge valves, and close the purifier oil-water separator blow-off valve;
    2) High-pressure blow-off: When the pressure of the purifier rises to the highest starting pressure, open the high-pressure air main inlet valve, and then open the air inlet valves of oxygen, nitrogen, and distillate partitions intermittently, and blow out repeatedly, to blow out the gas Until clean. When the high-pressure pressure is lower than the normal working pressure, the blowing should be temporarily stopped, and then blown when it reaches the highest starting pressure;
    3) Medium-pressure blow-off: After the high-pressure blow-off is completed, close the high-pressure air main inlet valve and open the oil-water separator blow-off valve at the same time. Install high-pressure and medium-pressure pressure gauges, install and close the section-1 valve. Close the blow-1 and blow-2 valves, then open the high-pressure air main inlet valve and close the blow-off valve. When the high-pressure pressure of the heat exchanger rises to the highest starting pressure, open the section-1 valve, and maintain the medium pressure in the range of 0.4 ~ 0.5MPa, the gas is discharged from the valve sleeve of section-3, section-4 valve. When the high-pressure pressure is lower than the normal working pressure, the joint-1 valve can be temporarily used, and then blown after the high-pressure pressure is increased, until there is no impurity in the blown gas;
    4) Low-pressure blow-off: After the medium-pressure blow-off is completed, the throttle-1 valve is closed, the blow-1 and blow-2 valves are opened, and the throttle valve-3 and throttle valve 4 are installed. Close the blow-off valve, open the section-1 valve, keep the medium pressure at about 0.5MPa, and open the section-3, section-4 valves and the oxygen and nitrogen vent valves and distillate discharge valves at the same time, blow off the low pressure, and pay attention to the low pressure. Greater than normal working pressure. Intermittent blowing 4 to 5 times.