Mitigation of BTEX Emissions through Optimization of Natural Gas Dew Point Control Unit

Abstract

The removal of water from natural gas is essential to prevent issues like equipment corrosion and hydrate formation, ensuring safe processing and transmission. During the dehydration process, glycol solvent absorbs not only water but also volatile organic compounds (VOCs) and aromatic compounds such as benzene, toluene, ethylbenzene, and xylene (BTEX). These harmful compounds are released into the atmosphere during glycol regeneration, causing environmental pollution and health problems. Natural gas dehydration can be achieved through methods like absorption, adsorption, and direct cooling of wet gas. This study focuses on direct cooling using JT Valve technology expansion, combined with monoethylene glycol (MEG) injection as a hydrate inhibitor. The aim is to improve the natural gas dew point and reduce BTEX emissions by optimizing operational conditions and examining the impact of variables on BTEX emissions and natural gas water and hydrocarbon content. The study is conducted on an existing natural gas dehydration unit (NGDU) in the Egyptian western desert. Simulation results show that factors such as JT upstream pressure, JT downstream pressure, MEG circulation rate, inlet gas temperature, and MEG reboiler temperature significantly affect the sales gas dew point. The proposed technique effectively eliminates BTEX emissions from the dehydration unit, demonstrating that direct cooling technology with JT Valve and MEG is a viable solution for mitigating BTEX emissions. Additionally, the study develops two quadratic correlations using regression analysis to accurately calculate the produced gas water content and hydrocarbon dew point under various operational conditions.