5
th
International Conference on Experiments/Process/System Modeling/Simulation/Optimization
5
th
IC-EpsMsO
Athens, 3-6 July, 2013
© IC-EpsMsO
TWO-PHASE GAS-LIQUID REACTING FLOW IN POROUS MEDIA
Dariusz Asendrych
1
, Pawel Niegodajew
1
, Stanislaw Drobniak
1
, Adam Tatarczuk
*
1
Czestochowa University of Technology, Institute of Thermal Machinery
al. Armii Krajowej 21, 42-200 Czestochowa, Poland
e-mail: imc@imc.pcz.czest.pl , web page: http://www.imc.pcz.pl
*
Institute of Chemical Processing of Coal, Centre for Process Studies
ul. Zamkowa 1, 41-803 Zabrze, Poland
e-mail: office@ichpw.zabrze.pl , web page: http://www.ichpw.zabrze.pl
Keywords: carbon capture & storage (CCS), multiphase flow, chemical absorption, porous media, CFD
Abstract. The paper is devoted to CFD modelling of the CO
2
capture from flue gases with the use of chemical
absorption. The model incorporates various physico-chemical submodels, in particular Eulerian countercurrent
2-phase gas-liquid flow in porous media, chemical reaction of CO
2
absorption/desorption combined with heat
release/consumption, inter-phase heat transfer and the water evaporation/condensation phenomena. The special
attention has been put on flow hydrodynamics in porous region, where a flow resistance and a liquid holdup
have to be modelled with special care. Moreover, a flow redistribution model has been adopted in a porous
region in order to adequately reconstruct liquid behaviour due to the geometry constraints of packed bed filling
elements. Due to high complexity of the model, its development and testing has been performed with the use of a
number of simplified models. Test simulations have shown a good agreement with experimental data acquired at
the reference pilot CCS installation proving the model relevance and its usefulness to industrial applications.
1 INTRODUCTION
The care about the environment enforces the reduction of greenhouse gases emission, in particular the
significant cuts in carbon dioxide being released from power industry. Carbon Capture and Storage (CCS) is
regarded as the most efficient solution for the near future allowing to achieve the CO
2
emission targets. Among
the available CCS technologies the "post-combustion" capture seems to be the most promising for
implementation into industrial practice in relatively short time
[9]
. The remaining two CCS methods, i.e. "pre-
combustion capture" and "oxy-fuel combustion"
[18]
require more research efforts and higher investments before
their introduction into power industry.
The present paper is devoted to the post
combustion capture which can be easily adopted
to the existing power plant installations operated
on different kinds of fossil fuels. Its
implementation requires to build the CCS unit
and to integrate it with the power plant cycle.
The principle of operation of capture unit is
presented in Fig. 1. Flue gases are sent through
the absorber where carbon dioxide is captured by
chemical absorption with the use of aqueous
monoethanolamine (MEA) solution supplied to
the column at its top. Both phases pass through
the packed bed where the most of the chemical
reaction occurs due to the enlarged contact area
between phases. The loaded MEA (containing
absorbed CO
2
) solution is pre-heated before
entering the desorber (stripper) where, with the
help of additional heat, the carbon dioxide is released, then sent to the compression unit and transported to the
storage location. The recycled MEA then flows through the heat exchanger (improving process efficiency) and
finally enters the absorber being ready for the next capture cycle. MEA is the most common choice of chemical
Figure 1. The process flow diagram for CO
2
capture in
a post-combustion method