In almost every gas processing plant, there will be natural gas dehydration unit. Sometimes, it is called dehydration unit (DHU) or dehydrator. When, I was working in Tripatra and involving in Senoro Gas Development Project, the facilities consisted of dehydration unit as one of them.
Natural gas dehydration unit is an important facilities in onshore and offshore gas processing plant. Its function are:
- To mitigate risk of water condensation, which leads to flow capacity issues (pipeline clogging and blocking)
- To prevent hydrate formation or to minimize corrosion
- To ensure smooth operation in downstream facilities. For example, gas pipeline is usually required 4-7 lb/MMSCF water content (87.2-152.6 ppm). For cryogenic unit (to produce LNG), water content in gas shall be less than 1 ppm. For CNG plant, before entering compressor unit, water content shall be reduced to maximum 3 lb/MMSCF to meet product specification.