Chemical Drying:
Chemical Drying is to fill Moisture absorption agent, Methanol usually.make use of Methanol’s strong Absortion ability of Moisture to dry the pipeline.This way costs less,but the Methanol must be disposed,it is contaminated.Meanwhile Methanol is easy to explode and burn,once wrongly disposed,it can be really dangerous.
Physical Drying:
Physical Drying is divided into Vacuum drying and dry air drying.The former is to make use of vacuum pump to create minus zero pressure in the pipeline,in this way the water boiling point becomes low and changes into air,then is pumped out.Thus the pipeline will be dried.This method fits very much stations and pipeline of changing diameter. But the weak point is high consume and high cost.
Dry Air Drying is to fill air of low dew-point into the pipeline,wait until it combines with the wet air and absorbs it to bring it out at the end.Keep filling in dry air at the launching point,the dry air keeps absorbing wet air and exhausts it.Finally the water dew-point is 5°C lower than the lowest surrounding tempreature required for Gas Transmission.This method is applied with foam pigs and fits long-distance pipeline drying.
Inner Structure of Dry Air Drying Machine
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