Improvement of natural gas dehydration performance by optimization of operating conditions: A case study in Sarkhun gas processing plant

• Process simulation of natural gas dehydration unit is done.
• Improvement of natural gas dehydration performance is investigated.
• Some modifications about operating condition are suggested.
• The water and hydrocarbon dew point temperatures improved by applying modifications.
• Reduction in greenhouse gas emission is achieved after modifications.

Water dew point adjustment unit is one of the main natural gas refinement processes for controlling the content of water and other impurities in natural gas to some allowable limit. Investigating the dew point adjustment unit of the Sarkhun gas processing facility revealed that due to inappropriate performance of liquid level control of the separators, this unit encountered hydrate formation and also the glycol consumption rate increased considerably. In this regard, the three phase separator and filters were simulated by steady state simulation software and the optimum separation temperature was determined. The operating condition of the dew point control unit was adjusted based on the optimum conditions achieved by simulation and for more investigation, experimental sampling was performed. The experimental results showed that the water and hydrocarbon dew point temperatures improved from −10 °C to −26 °C and from −5 °C to −9 °C, respectively after modifications. The outstanding achievement was a remarkable reduction in greenhouse gas emission after modifications mainly due to a considerable decrease in gas flared. According to experimental data, greenhouse gas production reduced by about 50% (decreased from 60,000 to 30,000 ton/year). More importantly, greater than 6000 tonnes of Liquified Petroleum Gas (LPG) was additionally produced annually per 1 MMSCM that provided additional annual income of about $11 million.