laboratory investigations of polyamine solvents for co...

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


increasing cycling capacity lower flow rate of solvent

working working capacitycapacity


increasing capacity per unit of solventsame absorption of CO2 by each amino-group


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


reaction rate of AEAE and DETA very similar to MEAfinal loading important

MEA 85%, AEAE and DETA 90% of equilibrium loading


complex molecules are reacting slower than MEAfor TEPA height of column has to be increased significantly


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


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!

laboratory investigations of polyamine solvents for co...

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