Investigation of the performance of a pilotscale CO2 desorption column using CFD simulations

Abstract

Technology Center Mongstad (TCM) is the world’s largest and most flexible test facility for amine based CO2 absorption and desorption. This master thesis is based on an operational problem at TCM where excess liquid loading is experienced at water inlet (from the distributor) to the packing section of a CO2 desorption column. This work is mainly focused on creating a CFD simulation of the stripper while having the geometry and problem of the TCM desorber column in mind for further improvements.

A literature search on CFD simulations on CO2 stripper, absorber and packing has been carried out. A 2D laminar CFD simulation of a CO2 capture stripper has been conducted using volume of fluid (VOF) method by OpenFOAM. The objective of this task is to perform a CFD simulation of a liquid flow distribution at the inlet of the packing area where the packing area is simulated as a porous zone.

The porous media is implemented in the middle of the desorber column where its performance is evaluated by observing the change in pressure in that zone. Illustrations showing the liquid phase distribution and relations to the change of pressure and velocity along y-axis have been simulated and evaluated. A case study on velocity and Darcy value has been conducted to see its result on liquid distribution on the packing area. The velocity ranges between 0.1 [m/s] to 2 [m/s] and the Darcy coefficient of Darcy-Forchheimer equation between 100 to 8.85*1010 (The value evaluates permeability of the liquid to the porous zone). The results on this report do not point any solution for the problem but it gives a base case to work further to solve the problem.

In order to improve the current CFD simulation work, reactingMultiphaseEulerFoam solver can be a better choice for this case. Further creating the geometry of the packing in a CAD software and implementing that geometry into OpenFOAM can give more valid results than using a porous media.

Technology Center Mongstad (TCM) is the world’s largest and most flexible test facility for amine based CO2 absorption and desorption. This master thesis is based on an operational problem at TCM where excess liquid loading is experienced at water inlet (from the distributor) to the packing section of a CO2 desorption column. This work is mainly focused on creating a CFD simulation of the stripper while having the geometry and problem of the TCM desorber column in mind for further improvements.

A literature search on CFD simulations on CO2 stripper, absorber and packing has been carried out. A 2D laminar CFD simulation of a CO2 capture stripper has been conducted using volume of fluid (VOF) method by OpenFOAM. The objective of this task is to perform a CFD simulation of a liquid flow distribution at the inlet of the packing area where the packing area is simulated as a porous zone.

The porous media is implemented in the middle of the desorber column where its performance is evaluated by observing the change in pressure in that zone. Illustrations showing the liquid phase distribution and relations to the change of pressure and velocity along y-axis have been simulated and evaluated. A case study on velocity and Darcy value has been conducted to see its result on liquid distribution on the packing area. The velocity ranges between 0.1 [m/s] to 2 [m/s] and the Darcy coefficient of Darcy-Forchheimer equation between 100 to 8.85*1010 (The value evaluates permeability of the liquid to the porous zone). The results on this report do not point any solution for the problem but it gives a base case to work further to solve the problem.

In order to improve the current CFD simulation work, reactingMultiphaseEulerFoam solver can be a better choice for this case. Further creating the geometry of the packing in a CAD software and implementing that geometry into OpenFOAM can give more valid results than using a porous media.