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Stability of a Benzyl Amine Based CO 2 CaptureAdsorbent in View of Regeneration Strategies

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ABSTRACT

Inthis work, the chemical and thermal stability of a primary amine-functionalizedion-exchange resin (Lewatit VP OC 1065) is studied in view of thepotential options of regenerating this sorbent in a CO2 removal application. The adsorbent was treated continuously in thepresence of air, different O2/CO2/N2 mixtures, concentrated CO2, and steam, and then the remainingCO2 adsorption capacity was measured. Elemental analysis,BET/BJH analysis, Fourier transform infrared spectroscopy, and thermogravimetricanalysis were applied to characterize adsorbent properties. This materialwas found to be thermally and hydrothermally stable at high temperatures.However, significant oxidative degradation occurred already at moderatetemperatures (above 70 °C). Temperatures above 120 °C leadto degradation in concentrated dry CO2. Adding moistureto the concentrated CO2 stream improves the CO2-induced stability. Adsorbent regeneration with nitrogen strippingis studied with various parameters, focusing on minimizing the molesof purge gas required per mole of CO2 desorbed.

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IR spectra for IER after treatment in dry 80% CO2 at120 °C and 100% dry CO2 at 150 °C for 72 h conditions,as well as for fresh urea and undegraded IER sample. Samples of IERwere pretreated at 100 °C in flowing N2 for 1 h thencooled.
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fig7: IR spectra for IER after treatment in dry 80% CO2 at120 °C and 100% dry CO2 at 150 °C for 72 h conditions,as well as for fresh urea and undegraded IER sample. Samples of IERwere pretreated at 100 °C in flowing N2 for 1 h thencooled.

Mentions: Using CO2 as purgegas for regeneration can be a relevantcondition when pure CO2 is targeted as product. Due tothe adsorption equilibrium, the required regeneration temperaturewhen using pure CO2 to desorb the sorbent is much higherthan for nitrogen stripping. According to the result of Alessi andKitchin,45 the resin used in this studycan regenerate completely under 1 atm of CO2 at 200 °C.However, the thermal stability turns out to be a problem at this temperaturefor the IER studied here. Based on the results on thermal stability,as shown in Figure 2, the maximum temperature of continuous CO2 exposure wasfound to be around 150 °C. We therefore evaluated the sorbentstability under 0.8 atm CO2 at 120 °C and at 1 atmof CO2 at 150 °C, as can be seen in Figure 6. By comparing of the resultsat 120 and 150 °C, we found that sorbent degradation increaseswith temperature and with the partial pressure of CO2.The loss of CO2 capacity is around 9% at 120 °C undercontinuous 80% CO2 exposure for 72 h. The degradation for(repeated) short periods of exposure was not tested, but this is probablybest tested in a multicycle duration test. The samples after the 72h continuous treatment were analyzed by FTIR, see Figure 7. The results of FTIR showthat the deactivated sample develops a peak at 1670 cm–1 and the intensity of this peak increases with the increased extentof degradation. The developed peak lays in the same range with theFTIR result of fresh urea, which points toward the formation of ureaafter treatment in concentrated CO2.


Stability of a Benzyl Amine Based CO 2 CaptureAdsorbent in View of Regeneration Strategies
IR spectra for IER after treatment in dry 80% CO2 at120 °C and 100% dry CO2 at 150 °C for 72 h conditions,as well as for fresh urea and undegraded IER sample. Samples of IERwere pretreated at 100 °C in flowing N2 for 1 h thencooled.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5384483&req=5

fig7: IR spectra for IER after treatment in dry 80% CO2 at120 °C and 100% dry CO2 at 150 °C for 72 h conditions,as well as for fresh urea and undegraded IER sample. Samples of IERwere pretreated at 100 °C in flowing N2 for 1 h thencooled.
Mentions: Using CO2 as purgegas for regeneration can be a relevantcondition when pure CO2 is targeted as product. Due tothe adsorption equilibrium, the required regeneration temperaturewhen using pure CO2 to desorb the sorbent is much higherthan for nitrogen stripping. According to the result of Alessi andKitchin,45 the resin used in this studycan regenerate completely under 1 atm of CO2 at 200 °C.However, the thermal stability turns out to be a problem at this temperaturefor the IER studied here. Based on the results on thermal stability,as shown in Figure 2, the maximum temperature of continuous CO2 exposure wasfound to be around 150 °C. We therefore evaluated the sorbentstability under 0.8 atm CO2 at 120 °C and at 1 atmof CO2 at 150 °C, as can be seen in Figure 6. By comparing of the resultsat 120 and 150 °C, we found that sorbent degradation increaseswith temperature and with the partial pressure of CO2.The loss of CO2 capacity is around 9% at 120 °C undercontinuous 80% CO2 exposure for 72 h. The degradation for(repeated) short periods of exposure was not tested, but this is probablybest tested in a multicycle duration test. The samples after the 72h continuous treatment were analyzed by FTIR, see Figure 7. The results of FTIR showthat the deactivated sample develops a peak at 1670 cm–1 and the intensity of this peak increases with the increased extentof degradation. The developed peak lays in the same range with theFTIR result of fresh urea, which points toward the formation of ureaafter treatment in concentrated CO2.

View Article: PubMed Central - PubMed

ABSTRACT

Inthis work, the chemical and thermal stability of a primary amine-functionalizedion-exchange resin (Lewatit VP OC 1065) is studied in view of thepotential options of regenerating this sorbent in a CO2 removal application. The adsorbent was treated continuously in thepresence of air, different O2/CO2/N2 mixtures, concentrated CO2, and steam, and then the remainingCO2 adsorption capacity was measured. Elemental analysis,BET/BJH analysis, Fourier transform infrared spectroscopy, and thermogravimetricanalysis were applied to characterize adsorbent properties. This materialwas found to be thermally and hydrothermally stable at high temperatures.However, significant oxidative degradation occurred already at moderatetemperatures (above 70 °C). Temperatures above 120 °C leadto degradation in concentrated dry CO2. Adding moistureto the concentrated CO2 stream improves the CO2-induced stability. Adsorbent regeneration with nitrogen strippingis studied with various parameters, focusing on minimizing the molesof purge gas required per mole of CO2 desorbed.

No MeSH data available.


Related in: MedlinePlus