Natural gas dehydration by desiccant materials

Abstract

Water vapor in a natural gas stream can result in line plugging due to hydrate formation, reduction of line capacity due to collection of free water in the line, and increased risk of damage to the pipeline due to the corrosive effects of water. Therefore, water vapor must be removed from natural gas to prevent hydrate formation and corrosion from condensed water. Gas dehydration is the process of removing water vapor from a gas stream to lower the temperature at which water will condense from the stream; this temperature is called the “dew point” of the gas. Molecular sieves are considered as one of the most important materials that are used as desiccant materials in industrial natural gas dehydration. This work shows a study of natural gas dehydration using 3A molecular sieve as a type of solid desiccant materials, the scope of this work was to build up a pilot scale unit for a natural gas dehydration as simulation of actual existing plant for Egyptian Western Desert Gas Company (WDGC). The effect of different operating conditions (water vapor concentration and gas flow rate) on dehydration of natural gas was studied. The experimental setup consists of cylinder filled with 3A molecular sieve to form a fixed bed, then pass through this bed natural gas with different water vapor concentration, The experimental setup is fitted with facilities to control bed pressure, flow rate, measure water vapor concentration and bed temperature, a gas heater was used to activate molecular sieve bed. Increasing water vapor concentration in inlet feed gas leads to a marked decrease in dehydration efficiency. As expected, a higher inlet flow rate of natural gas decrease dehydration efficiency. Increasing feed pressure leads to higher dehydration efficiency.