Energy consumption simulation and optimization of the triethylene glycol dehydration process in the natural gas industry

Abstract

Triethylene glycol (TEG) dehydration systems frequently suffer from high energy consumption due to localized thermal inefficiencies. This study proposes an integrated retrofitting framework for a practical TEG unit in Southwest China, physically capturing and repurposing waste heat from both overhead vapor and reboiler flue gas. An iterative mathematical model, validated against plant data with a maximum relative uncertainty strictly below 5%, was developed to quantify the thermodynamic and economic improvements. The optimized system reduces overall fuel gas consumption by 44.86% and increases reboiler thermal efficiency from 39.23% to 44.66%. By reusing the cooled overhead vapor as supplementary reboiler fuel and completely eliminating the incinerator, the proposed retrofit achieves a rapid investment payback period of 9.2 months. Furthermore, this structural modification physically prevents the emission of 206.5 tons of CO ₂ equivalent annually and eliminates trace volatile organic compound (VOC) flaring. Sensitivity analysis identifies the excess air factor in the reboiler's ejector burner as the most critical parameter influencing system performance, providing clear guidance for future industrial upgrades.