Thermodynamics of CO2-MDEA using eNRTL with Differential Evolution Algorithm

Abstract

Carbon dioxide (CO 2 ) capture by absorption with aqueous alkanolamines is considered as an important technology to reduce CO 2 emissions and to help alleviate global climate change. To understand more the thermodynamics of some of the CO 2 -Amines, the NRTL electrolyte model has been used to simulate the behaviour of carbon dioxide absorption by some amines. To determine NRTL interaction parameters of the model, VLE, heat capacity and excess enthalpy data have been used. In this study, carbon dioxide, water and Methyl DiEthanolAmine (MDEA) ternary system are used to calculate eNRTL (electrolyte Non-Ramdom Two Liquid) interaction parameters, and the system was modelled using VLE data available in the literature. Differential evolution algorithm (DE), an evolutionary computational technique, has been used to estimate NRTL parameters model to predict the VLE of CO 2 with MDEA. Differential Evolution algorithm (DE) have been used to compare it with annealing (SA) and deterministic technique like Levenberg-Marquardt (LM) using one set of experimental data for MDEA-H 2 O system. Its standard deviation is lower than those of SA and LM algorithms when used to regress the eNRTL binary interactions parameters for MDEA-H 2 O Keywords: Themodynamics of Electrolytes; CO 2 Capture; MDEA; Differential Evolution; NRTL. IntroductionDifferential Evolution (DE) algorithm is a new heuristic approach mainly having three advantages; finding the true global minimum regardless of the initial parameter values, fast convergence, and using few control parameters. DE algorithm is a population based algorithm like genetic algorithms using similar operators; crossover, mutation and selection. However, the success of DE in solving a specific problem crucially depends on appropriately choosing trial vector generation strategies and their associated control parameter values. Employing a trial-and-error scheme to search for the most suitable strategy and its associated parameter settings requires high computational costs. Moreover, at different stages of evolution, different strategies coupled with different parameter settings may be required in order to achieve the best performance. The NRTL-electrolyte model has been used for CO 2 absorption by MDEA where DE has been applied to have a better optimisation of the model. Scalable simulation, design, and optimization of the CO 2 capture processes start with modeling of the thermodynamic properties, specifically vapor-liquid equilibrium (VLE) and chemical reaction equilibrium, as well as calorimetric properties. Accurate modeling of thermodynamic properties requires availability of reliable experimental data. For the rational gas treating processes

CO2 Capture Modeling, Energy Savings, and Heat Pump Integration

“…Vivier et al independently examine use of the NRTL model for aqueous MEA with CO 2 through use of differential evolution algorithms . Kamalpour and Mehablia conduct a similar study for MDEA using the fuller ENRTL model …”