After the production overhaul was over, the molecular sieve was activated and the naked cold leak detection was normal. After the bare cooling was completed, two expanders were shut down and the whole tower was heated. After the heating is completed, close all valves inside and outside the device, and inflate the pressure, remove the maintenance shelf, clean the foundation of the cold box and dry it, and fill it with pearl sand. After loading sand, the air compressor is started to supply air to the air separation equipment. The product specifications and various operating process parameters of the air separation equipment meet or exceed the design requirements, and the phenomenon of ice running outside the main cold box is completely eliminated.
Experience and experience, the leak detection confirmation after the installation or overhaul of the air separation equipment must be in place, and no dead angles should be left. The leakage of low temperature gas and liquid in the cold box is also the main factor for the failure of the air separation equipment. During installation and pressure test leak detection It must be strictly checked to ensure that there is no leakage point before the closed cold box is filled with sand and put into production. The pipeline layout in the cold box should be reasonable, and try to avoid low-temperature equipment close to the cold box wall. Because the cold box plate material is ordinary carbon steel, it will produce embrittlement under low temperature environment for a long time, which is also the main reason for the cold box plate freeze cracking. At the same time, the equipment shall be repaired and repaired in time when the equipment reaches the prescribed period. Try to reduce the number of temporary shutdowns of the air separation plant. Changes in thermal expansion and contraction stress will affect the service life of the pipeline.
The air separation equipment should be heated thoroughly every time. When the air separation equipment is heated, the pearlite sand inside the cold box is often thawed, but the other parts still maintain a low temperature. If the pearlite sand is wet and frozen, it is easy to cause The pipe deformation in the tower is damaged. Add pearlescent sand in time. After the equipment has been running for a period of time, the pearlite in the cold box will sink and needs to be replenished in time. At the same time, the pearlite in the cold box should be kept dry. The cold box of the air separation plant should be filled with enough dry and dirty nitrogen during normal operation. During the temporary stop, the dry box must be connected to the outside to inflate the cold box. Do a good job of sealing the cold box. The process pipe inlet and outlet cold boxes should be re-sealed with glue every 5 years or so. The seals of the manholes at the top of the main and small cold boxes should be checked frequently to prevent rainwater from leaking into the cold boxes. It is recommended to use waterproof cloth.
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