A new flowsheeting tool for flue gas treating

E.P. van Elk, A.R.J. Arendsen, G.F. Versteeg

Abstract

A new flowsheeting tool, specifically designed for steady-state simulation of acid gas treating processes, has been developed. The models implemented in the new tool combine all issues relevant for the design, optimization and analysis of acid gas treating processes, including post-combustion and pre-combustion carbon dioxide capture. The computer code consists of an extremely user-friendly graphical user interface and a very powerful numerical simulator that handles rigorous modeling of thermodynamics, activity based kinetics, rate-based mass transfer and supports all unit operations relevant for gas treating plants (absorbers, strippers, flash drums, heaters, pumps, compressors, mixers and splitters, etc.).
Although the simulator can be used as a multifunctional steady state flowsheeting program, it has been specifically designed for acid gas treating applications. The program includes an extensive database of thermodynamic parameters, interaction coefficients, kinetics, etc. that has been optimized to accurately predict the vapor liquid equilibriums (VLE), thermodynamic and physical properties and the kinetically enhanced mass transfer (both analytical and rigorous) of amine based capturing processes. The program applies the Electrolyte Equation of State (E-EOS) thermodynamic model, which is expected to better predict the behavior of acid gas treating processes than conventional models often applied, like e.g. Kent-Eisenberg or more complex activity based models like Pitzer, Deshmukh-Mather or ElecNRTL. Alternative thermodynamic models can, however, easily be implemented in the simulator.
For the optimal prediction of column performances, the program includes a database of various tray types, as well as a large collection of both dumped and structured packing respectively. Several mass transfer and hydrodynamic models have been implemented that benefit from accurate physical property models (density, viscosity, surface tension, diffusivity, conductivity) specifically selected for acid gas treating applications. The tool is able to describe complete acid gas treating processes, including complex processes with multiple (mixed or hybrid) solvent loops, and is able to significantly improve the understanding of the performance of potential new solvents.

Keywords: flowsheeting; simulator; rate-based; gas treating; carbon dioxode capture; flue gas; absorption; stripping