Techno-Economic Analysis of a Natural Gas Dehydration System: A Case Study of an “X” Processing Plant in the Niger Delta

Abstract

The presence of water in the natural gas stream could cause pipeline corrosion, limit pipeline flow capacities, pipeline blockages and possible damage to process filters, valves, and compressors. The absorption gas dehydration system with Triethylene Glycol (TEG) as an inhibitor is the most widely used and reliable gas dehydration system for non-cryogenic pipeline operation. TEG losses have been a serious concern to the operation personnel in “X” dehydration Plant in the Niger Delta region of Nigeria. This study therefore presents the economic analyses of gas dehydration by the introduction of a stripping (sales) gas to the TEG regenerator-reboiler to enhance the vapor separation and scrub off any gaseous impurities that may still exist in the rich TEG. The existing dehydration units were modeled and process parameters were simulated using Aspen HYSYS® software. An instance from the simulation results shows that, for a TEG flow rate of 0.4543 m3/h, 97% of TEG was recovered. However, with the introduction of a dry natural gas to the reboiler, 99.98% of the TEG was recovered. This significant improvement, which represents 10.2 kg/h of TEG recovery, translates to a cost saving of approximately $89,352 per year.

Keywords

• gas processing plants
• niger delta
• teg absorption units
• gas dehydration