Gas Dehydration Methods
Before gas can be sold the gas need to be dehydrated from its water content. This efforts need to be done to prevents hydrates and water vapor. The water vapor in gas line could create corrosion problems. There are many methods to dry the gas:
1. Cool the gas until it forms the hydrate formation and separate the water. This methods will leave high water content (±30 lb/MMscfd)
2. Low-temperature Exchange (LTX) unit can be used to melt the forming hydrates. The problem with LTX is it needs high inlet pressure (2,500 psi) to work effectively.
3. Use CaCl2 to reduce the moisture by contact reaction. This method is not commons since it’s very corrosive and can’t be regenerated.
4. Use regenerated solid desiccant (alumina, silica gel, molecular sieve). They can absorb the moisture to a very low level but it’s expensive.
5. Use methanol or ethylene glycol as liquid desiccant. Although it can’t be regenerated but it’s not expensive so it widely uses to hydrate the gas well flow line to prevent the hydrates from freezing the choke.
6. Use regenerated glycol to dry the gas. This is the most common method of gas dehydration system.
Categories: Gas Processing | Tags: Gas Dehydration, Glycol, liquid desiccant, Low-temperature Exchange, solid desiccant | Leave a comment