Modelling of reactive absorption for natural gas treatment

Abstract

The objective of this work is to create a model to simulate the absorption of CO2 using monoethanolamine solution. CO2 is a problem for natural gas, since it reduces its calorific capacity, accelerates corrosion in ducts, and also may freeze cryogenic processing lines in a traditional gas treatment plant. Reactive absorption of CO2 using alkanolamines is the most consolidated method of removing this contaminant from natural gas. Therefore, a good model of this unit is paramount for correct design, operation and optimization. A rigorous rate-based two-film model was proposed for modelling absorption of CO2 using monoethanolamine. Discretization with finite volumes was performed to solve the resulting partial differential equation system. Three models were then proposed to solve the algebraic-differential equation system, each with decreasing number of simplifications in order to generate initial guesses for the final solution. The model was validaded using literature data from pilot plant, and the interfacial area parameter was adjusted. Finally, some case studies were simulated in order to verify its consistency.