All natural gas contains water vapour. Said water must be removed to a content of 7 lb/MMSCF for most gas transmission systems and to as low as partial ppm water with dew points lower than –150 °F for cryogenic processing feed pre-treatment.
Gas dehydration prevents hydrate formation, potential plugging, and corrosion in the gas gathering, transmission system, or processing plant. KOCKEN Energy Systems Inc. Natural Gas Dehydrators are selected and constructed in accordance with GPSA Section 20, API 12GDU (when applicable) and all other applicable Industry Codes and Standards.
There are several process options that can be utilized to accomplish dehydration. KOCKEN offers a vast array of these processes consisting of the five basic below:
- Compression to a higher pressure with subsequent cooling and phase separation. The higher the pressure, the lower the saturated water vapour content in lb/MMSCF at a given temperature
- Cooling below initial dew-point
- Absorption with liquid desiccants
- Adsorption with solid desiccants
- Absorption with a deliquescing solid
KOCKEN considers any and all combinations of the available technology processes considering a combination of factors including:
- Water content specification
- Initial water content
- Process character
- Operational nature
- Economic factors
When gas is to be transported for long distances in pipelines, consideration must be given to the control of the formation of hydrates in the transmission system. To prevent formation of said hydrates, it is necessary to control the Water Dewpoint at a temperature below all conceivable operating tempera- tures. KOCKEN Sistemas de Energia Inc. offers a TEG Gas Dehydration Systems that can achieve wa- ter dewpoint depressions as high as 180F.
The glycol gas dehydrator design employs a contactor to provide intimate contact between the mois- ture laden natural gas and the dry glycol desiccant. The glycol regenerator consists of a reboiler, still column, stripping column and surge tank and is equipped with a natural gas fueled flame arrested burner. The glycol pump is typically a glycol-gas powered unit that utilizes energy from the high pres- sure rich glycol along with a small amount of high pressure gas to circulate the lean glycol.
All KOCKEN TEG Gas Dehydration Units are constructed according to the API 12GDU Specification for Glycol-Type Gas Dehydration Units, GPSA Section 20, ASME SectioN VIII, Division 1, and applica- ble Industry Codes and Standards unless stipulated otherwise.
- 3-Phase Glycol Flash Separator for reduced TEG losses. 2-Phase Fuel Gas Scrubber.
- 3rd Phase Controls on TEG Contactor.
- Particulate & Carbon Filtration.
- Standby and electric pump(s).
- Standard Design: 4#/MMSCF water content in outlet gas with lean TEG purity of 99.7%.
- Reflux coil incorporated in standard design for reduced TEG losses.
- High dewpoint depression units w/ water content in out- let gas as low 10ppm and TEG purities in excess of 99.99%.
- Azeotropic distillation for increased TEG purity with no stripping gas, decreased emissions, and lower TEG losses.