laboratory investigations of polyamine solvents for co...
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Universität StuttgartProf. Dr. techn. G. Scheffknecht
Institut für Verfahrenstechnik und DampfkesselwesenInstitute of Process Engineering and Power Plant Technology
Laboratory Investigations of Polyamine Solvents for
CO2 -Scrubbing from Flue Gases
Dipl.-Ing. K. BrechtelProf. Dr. techn. G. Scheffknecht
Dr.-Ing. S. Unterberger
4th International Conference on Clean Coal Technologies, Dresden, 18. – 20.05.2009
Universität StuttgartBase Case: Monoethanolamine
rich loading~0,45mol CO2 / mol MEA
lean loading~0,2-0,25mol CO2 / mol MEA
energy demandfor regeneration
3,7-4,2MJ/ kg CO2
pressure loss~4mbar/m
energy efficiency of power plant
minus ~13%-points
Universität Stuttgart
energy required for regenerationheat of reactionsensible heatheat of water vaporization
Qregeneration = Qdes + Qsens + Qstrip
energy saving bynew solvent (heat of reaction)lower circulation rate/ higher working capacity(sensible heat)solvent and process (water vapor)
Base Case: Monoethanolamine
energy efficiency of power plant
minus ~13%-points
50% heat of reaction20% sensible heat30% vaporization
50% heat of reaction20% sensible heat30% vaporization
Universität StuttgartAmine Investigation: Laboratory Setup
synthetic flue gas
investigation of amines atdifferent temperatures
determination of equilibrium loadingof amines
reference Monoethanolamine (MEA)temperature influencecomparison of amines
Universität StuttgartInvestigation of Polyamines
experiments based on 20% MEA as referenceall amines in equivalent ratio to MEA based on number of amino groupsall tested solution contain the same number of amino-groups
Universität StuttgartEquilibrium Loading of Amines
Universität StuttgartEquilibrium Loading of Amines
increasing cycling capacity lower flow rate of solvent
working working capacitycapacity
Universität StuttgartEquilibrium Loading of Amines
increasing capacity per unit of solventsame absorption of CO2 by each amino-group
Universität Stuttgart
more realistic testCO2 absorption by surface contact of gas and solventcolumn height defines contact timereaction rate plays significant role
test setupsimple glass columninsulatedsampling points for profilemeasurements (gas + temperature)
Wetted Wall Column
heated synthetic gas flow loaded amine
CO2 reduced gasnew solvent
temperature and gas sampling
points
Universität StuttgartWetted Wall Column
high CO2 uptake in the bottom (high CO2 concentration area)50% of height for 30% of CO2 removal
Universität StuttgartWetted Wall Column
reaction rate of AEAE and DETA very similar to MEAfinal loading important
MEA 85%, AEAE and DETA 90% of equilibrium loading
Universität StuttgartWetted Wall Column
complex molecules are reacting slower than MEAfor TEPA height of column has to be increased significantly
Universität StuttgartWetted Wall Column
same column design possible for MEA, AEAE and DETAhigh increase in necessary height for TETA and TEPA
Universität StuttgartConclusions
equilibrium loading testslow concentration of polyamine necessary to reach equal MEA concentrationdifferent working capacities depending on used amineworking capacity increase by mol but not by amino groupdirect link of number of amino groups and absorbed amount of CO2
higher working capacity lead to lower circulation rate
wetted wall columnreaction rate plays significant rolelow height for bulk removalAEAE and DETA perform as well as MEATETA and TEPA need higher columns
Universität StuttgartOutlook
investigation of solvents still on the waydegradation experimentshigher concentrated amine solutionsevaluation of additives to prevent degradationlow thermal regeneration
new design of absorberopen spray towerno packingnew process parameter: absorptionover droplet-surfacerecirculation for bulk removal
Universität Stuttgart
Thank you for your attention!Thank you for your attention!
We would like to thank the We would like to thank the EnBWEnBW KraftwerkeKraftwerke AG AG for their support of this work!for their support of this work!