Abstract
Amine-silica adsorbents are considered alternatives to aqueous solutions of amines, which have been traditionally used to capture carbon dioxide (CO 2) from flue gas. Among amine-silica adsorbents, polyethyleneimine (PEI)-silica is particularly effective at capturing CO 2 from flue gas due to its high thermal stability. In this study, we investigated the influence of PEI type (i.e. branched vs. linear) and molecular weight on the CO 2 capture performance of PEI-silica adsorbents. PEI molecular weight influenced the thermal stability of PEI-silica adsorbents; however, when the molecular weight was ≥1200Da the increase in stability was negligible in the temperature range of 25-160°C. Branched PEIs (BPEIs) achieved higher CO 2 saturated sorption capacities compared to linear PEIs (LPEIs); however, LPEIs were more stable than BPEIs during CO 2 sorption-desorption cycling. PEI molecular weight also influenced the CO 2 saturated sorption capacity; CO 2 saturated sorption capacity decreased as PEI molecular weight increased, and among the adsorbents tested in this study BPEI/800-silica had the highest CO 2 saturated sorption capacity (202mg CO 2/g adsorbent). Both PEI type and molecular weight exhibited influence on the sorption or desorption heat of PEI-silica adsorbents. The CO 2 regeneration heat was much lower than that of MEA solution for all PEI-silica adsorbents tested in this study.
| Original language | English |
|---|---|
| Pages (from-to) | 750-755 |
| Number of pages | 6 |
| Journal | Applied Energy |
| Volume | 136 |
| DOIs | |
| Publication status | Published - 31 Dec 2014 |
| Externally published | Yes |
Keywords
- Carbon capture
- Polyethyleneimine
- CO2 adsorbent
- Nano silica
- CARBON-DIOXIDE
- POSTCOMBUSTION CAPTURE
- AMINE SORBENTS
- HIGH-CAPACITY
- ADSORPTION
- SBA-15
- DESORPTION
- KINETICS
- TEMPERATURES
- ZEOLITES