Assessment of chemical enhancement and energy consumption of natural gas dehydration processes

Abstract

Water vapors are found in high concentrations during natural gas production and processing. Energy consumption is known to be a drawback of the glycol dehydration process. Toxic and greenhouse gas emissions are another drawback from the environmental point of view. This paper served to propose a solution to the two problems together by using an emissions stream from the regenerator distillation tower to serve as a striping gas which solved the environmental problem of emissions and helped to reduce energy consumption. Aspen HYSYS was used to model glycol dehydrating as the most widely used and economically viable technique for drying off natural gas streams. This method uses the solvent tri ethylene glycol (TEG) as the absorbent. The focus of this research is to analyze sensitivity to the modeling outcomes. Furthermore, the results suggest that the process might be enhanced and save energy consumption. The simulation used three different tri-ethylene glycol flows, stripping gas flows, and different reboiler temperatures were used in the simulation. The modeling technique was effective in decreasing the water content in the regeneration column from 75lb/MMSCF to 2.5lb/MMSCF and saving energy consumption during the dehydration of natural gas. However, the results showed that in the fourth case when the amount of triethylene glycol is equal to 665.3 kg/h, and reboiler energy is equal to 247300 kJ/h, therefore the energy consumed per kilogram of the TEG is equal to 371.7 kJ/kg which represents the lowest amount of energy consumed during solvent regeneration. However, the results suggest that using emissions as a stripping gas can increase TEG purity and boost the efficiency of the dehydration plant, which appears to be a better option in the long run. The results suggest that the demonstrated approach may help towards decarbonization and zero emission of the dehydration process.