DESALTERS & DEHYDRATORS

Oil production is typically accompanied with the production of water from the well and this water needs to be removed in order to meet prescribed BS&W specifications. By removing produced water, one also limits the volume of water transported, for sales agreements and for refinery feedstock for maximum commercial value.

Crude oil will also contain salt which will be present in the water as soluble mineral salts. Therefore the removal of the water also removes salt. In some processing applications it may be necessary to desalt in two stages, with the addition of lower salinity dilution water being used between the stages.

Typical dilution rates may be in the order of 3-4% of the oil flowrate. In some cases, in order to save fresh water, it may be possible to inject seawater with the fresh water into the feedstock to meet the required outlet salt and BS&W specification. A full salt balance is completed to provide the optimum solution for dilution water flowrate versus BS&W specification, and any specified oil in water requirements.

GAS DEHYDRATION

Glycol dehydration is used to dehydrate gas streams in order to meet pipeline specifications and is accomplished by absorption of the water vapour using a glycol stream. The wet rich glycol stream is then recycled to the regeneration package for reconditioning ready for reuse. Triethylene Glycol (TEG) has gained the widest acceptance because it permits higher dew point depressions of natural gas and is more easily regenerated.

DPS have a tremendous amount of knowledge when it comes to the design of process packages and are developing a new generation of products to give our customers a range of standard and compact solutions.