The heat capacity of Plate-fin switching heat exchanger is small,Air separation equipmentThe start time is short, at 30 ~ 36 H level; the start time of the air separation unit with stone cooler needs 48 ~ 60h.
In terms of operation, master the essentials of operation: prevent moisture and carbon dioxide from being brought into the tower; strictly control the temperature difference between the cold end and the hot end; pay attention to the cooling of the main cooling; give full play to the refrigeration capacity of multiple expansion machines; reasonable allocation and utilization of cooling capacity, depending on the potential of the equipment itself to shorten the start-up time.
Because of the large heat capacity of the stone cooler, it takes quite a long time to cool down to normal temperature after heating. The air of the turbine air compressor can be used to blow the stuffing to near normal temperature before starting the expansion machine, and hot air can be discharged from the automatic valve box. In this way, the precooling time of the stuffing can be shortened.
In addition, using external cold source is also an effective way to shorten the start-up time. When the main cooling is over and liquid appears, input liquid oxygen, liquid or liquid nitrogen from the outside. The method of infusion is to connect the liquid source with the liquid oxygen discharge valve, open the liquid oxygen discharge valve and inject the external liquid into the main cooling. When the main cold liquid level reaches the normal liquid level, the infusion can be stopped, and the air separation tower can enter the stage of purging. With this infusion technology, the start-up time can be shortened by more than 12 hours. This is a very economical method, which has been applied in many units and has achieved practical energy saving effect.
The source of the liquid can be provided by another running air separation plant; it can also be discharged into the storage tank for standby when parking; it can also be introduced from the low temperature storage tank of liquid oxygen.
