Process introduction of TEG dehydration plant in the natural gas treating skid

Solvent absorption method is one of the most commonly used dehydration process in the natural gas processing industry, TEG dehydration (triethylene glycol dehydration) is usually used as a kind of Solvent. It utilizes the absorption principle and uses glycol substances (such as triethylene glycol) as absorbents to fully contact with natural gas, transferring water to the solvent to achieve dehydration.

After exiting the tower, it enters a casing heat exchanger and exchanges heat with the hot lean glycol before entering tower to reduce the temperature of the TEG. The natural gas after heat exchange enters the filter separator to separate the carried glycol and then enters the external pipeline. The rich TEG that has absorbed the moisture in the natural gas flows out from the absorption tower and enters the liquid level regulating valve, and after depressurization, it enters the reflux cooling coil at the top of the rich liquid rectification column and exchanges heat with the hot steam generated in the reboiler to provide column top reflux. After providing the column top reflux cooling capacity, it is heated to about 50 ℃, and then goes out of the coil to the TEG flash tank. The rich glycol is depressurized to 0.4mpa~0.6mpa in the flash tank, and the hydrocarbon gas and other gases dissolved in the TEG are flashed out, and this part of the gas is used as the fuel gas for the reboiler combustion.

The flashed rich liquid TEG enters the mechanical filter to filter out the mechanical impurities, and then enters the activated carbon filter to further adsorb the hydrocarbon substances dissolved in the TEG and the degraded substances of the TEG. Then it enters the plate-type lean-rich liquid heat exchanger, exchanges heat with the high-temperature lean TEG from the heat exchange buffer tank at the lower part of the TEG reboiler, and heats up to ~150 °C to enter the rich liquid rectification column.

In the TEG reboiler at the lower part of the rectification column, the TEG is heated to 193 ℃ , and the water in the TEG is fractionated and discharged from the top of the rectification column through the fractionation effect of the rectification column. The lean glycol with a concentration of about 99% (wt) overflows from the lean liquid stripping column in the reboiler to the lower TEG heat exchange buffer tank. Under the action of the dry gas in the lean liquid stripping column, the lean glycol concentration entering the heat exchange buffer tank can reach 99.5%~99.8%.

In the glycol buffer tank, the lean glycol with a temperature of about 193 °C enters the lean-rich glycol heat exchanger to exchange heat with the rich glycol, and the temperature drops to about 100 °C and enters the pump. The lean liquid TEG is pumped into the gas-liquid heat exchanger outside the absorption tower, and after cooling with the gas heat exchanger out of the tower, it enters the top of the absorption tower from the upper part of the casing to complete the solvent circulation.

Contact:

Sichuan Hengzhong Automation Equipment Co., Ltd.

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