Dehydration of Gas Mixture Using Throttling Valve: Effect of Pressure & Effect on Moisture Content

Natural gas hydrate has always bring major problem to pipelines corrosion and plugging. Many technologies have been invented and applied to tackle this problem. The widely used and most feasible technologies used is absorption by using triethylene glycol (TEG). This technology has been used in industry for decades due to its promising efficiency. However, its packing column requires a large column space for maximizing the absorption amount. Besides, there are other drawbacks of using this method such as desiccant effectiveness which decreases promptly at temperatures greater than 80°F (26.67°C) and high energy consumption. Hence, the throttling technique is proposed to remove moisture content in natural gas mixture in achieving the essentials for critical offshore application, which removes water vapor in large production, small size and less weight. The advantage of the proposed system include self-induced refrigeration, small in size, low operating cost, simple mechanical design and unlikely to form hydrates. In this project, relationship between feed pressure and temperature drop in a throttling valve is studied. On top of that, the effect on different moisture content in hydrocarbon mixture with various throttling pressure is studied. Mathematical study is also developed to model and validate the temperature drop for different gas mixture under different feed pressure in a throttling valve. Calculated value is compared with experimental data to study the contributing factor of efficient water removal. Dehydration via throttling valve can be achieved by controlling the parameters: eg., increasing the feed pressure with constant temperature and increasing the feed temperature with inlet pressure kept constant. The dehydration of gas mixture by using throttling valve deemed a valuable result noting that the effectiveness of the throttling valve can go up to 87% if a proper insulation is installed.