ExxonMobil develops new way to dehydrate gas

EXXONMOBIL has developed a new, patented natural gas dehydration system, called cMIST, which it says could replace conventional large dehydration towers.

The in-line cMIST system can reduce the surface footprint of a dehydration system by 70%, according to the oil giant, and is half the weight of a conventional system, which is particularly relevant for offshore systems. It is also cheaper. ExxonMobil has extensively field-tested the system, and president of ExxonMobil Upstream Research Company, Tom Schuessler, describes the technology as a “step-change in operational efficiency”.

cMIST uses a proprietary droplet generator, which breaks up conventional glycol solvents into small droplets which can then be easily dispersed throughout the gas flow. The energy to create the droplets comes from the gas flow itself. The droplets have a very small surface area which can efficiently absorb any water vapour in the natural gas. An inline separator will coalesce the glycol droplets, which are then moved to the outside edge of the pipe wall for easy collection. Another conventional system removes the water from the glycol, which is then reused in the droplet generator.

ExxonMobil has licensed cMIST to Chemtech, a division of Sulzer and one of the leading companies in separation technology, which will deploy the technology in the oil and gas industry.

Torsten Wintergerste, Chemtech president, said that the technology will allow for “much needed reductions in capital expenditures for both greenfield projects and existing facilities seeking brownfield debottlenecking opportunities.”