Simulation of an Offshore Natural Gas Purification Process for CO₂ Removal with Gas–Liquid Contactors Employing Aqueous Solutions of Ethanolamines

In the scenario of offshore rigs angular indifference, modularity, and compactness strongly influence selection of technology for natural gas purification. Gas–liquid contactors have such attributes and perform gas absorption without the concerns of packing columns like weight, flooding, gravitational alignment, and water saturation. This paper proposes a model for gas–liquid hollow fiber contactors using aqueous alkanolamines for CO₂ removal from high pressure natural gas. The model assumes high-pressure compressible flows of both permeate and retentate with full thermodynamics via equations of state. Permeate is approached as a reactive vapor–liquid equilibrium flow of solvent with CO₂/CH₄ from membrane fluxes. Phase change and reactive heat effects are modeled via mass, energy, and momentum balances written for permeate/retentate as a differential-algebraic system for dependent variables temperature, pressure, and component flows. Profiles are obtained via numerical spatial integration with algebraic resolution imbedded, accounting for permeate reactive vapor–liquid equilibrium with only the molecular species incorporated into a Chemical Theory framework