JT Unit Skids |
Joule-Thompson Effect | Operational Temperatures
DPC has JT units operating as warm as 60°F and as cold as -15°F.
- Warm Operations:
A warm operation is when the cold separator of a JT unit operates at anything 40°F or higher. Warm operations are usually stable as long as the unit has no greater than 7#/MMSCF of water entering it. Methanol injection is used to handle water spikes above 7#/MMSCF.
- Cold Operations:
A cold operation is when the cold separator is operating between 30°F and 20°F. To successfully operate a unit in this range, the operator must either operate his TEG system to produce 3#/MMSCF water or rely on a good methanol distribution system. 7#/MMSCF water has a water dew point of approximately 30°F at typical transporting pipeline pressures. Therefore when operating at these temperatures with 7#/MMSCF gas, free water droplets will form. Free water will either form hydrates or freeze into ice. Without a good distribution of a suppressant like methanol, the JT unit will foul it's heat transfer surface, plug off with ice and hydrates, and ultimately stop working. The lost sales associated with only a couple hours of down time will greatly offset any savings from the rental of a JT unit from a low-quality provider. This is the major cause of downtime with JT operations.
- Very Cold Operations:
DPC defines this as any temperature below 20°F. In these cases special care must be taken. DPC highly recommends that gas water contents be lower than 2#/MMSCF for reliable operations.
METHANOL INJECTION IS ONLY A SUPPLEMENT TO GOOD DEHYDRATION OPERATIONS
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