When the small air separation unit fractionation tower cooling start, in addition to into the booster compressor and directly into the air under the tower, air turbine compressor discharge air from the venting valve to keep the compressor discharge pressure unchanged. As the temperature of each part of the fractionation tower gradually decreases, the amount of air inhaled will gradually increase, at this time can gradually close the air compressor venting valve. When the cold end of the main converter temperature close to the air liquefaction temperature (-172 ℃), small air separation unit cooling stage is over.
Issues to be noted during the cooling process.
Opening the valves of the cooling process in sequence.
Keeping the discharge pressure of the air turbine compressor and booster compressor stable.
The molecular sieve purifier regeneration gas from the air flow path to the dirty nitrogen flow path.
4, must control the flow rate through each flow path to ensure that the temperature of each part of the cold box falls evenly, there should not be a large temperature drop to prevent large thermal stress due to the large temperature drop.
5, cooling process, in order to accelerate the cooling, you can open each blow-off valve in turn, fold open the meter valve connector, open the meter valve to blow off, in order to discharge part of the hot gas until frost, and then close.
Dear Air Separation has detailed studies and specifications on the operation of complete sets of small air separation units, large air separation units and liquid air separation plants, to ensure the safe and stable operation of small air separation units, large air separation units and liquid air separation plants.
