This report shows the findings of experiments conducted for the screening of potential carbon dioxide absorbing materials (CAMs) for the capture of CO2. This report is done to assess the CO2 absorption performance of nine potential absorbents. The absorbents are CaO, Ca(OH)2, MnO2, ZnO, CuO, PbO, MgO, Na2CO3 and K2CO3. CO2 is the reaction gas used and together with N2 and air, they form the reactive and inert environment for the experiments. The experiments are carried out using the ATI Cahn TG-121 model thermo-gravimetric analyser (TGA). Other equipments include TGA-linked computer, gas control panel, gas regulators, gas bottles, gas tubes, sample containers, chemical scoop, sealing tapes, stainless steel forceps and oven. The running of the experiments is automated by establishing the methods in the computer using the TG software. It also allows automatic collection and saving of TG run data. The conduction of the experiments are split into 10-cycle and 1-cycle test with the latter done for testing the effect of sample mass. In chapter 4, almost all 10-cycle TG runs show a shifting trend of positive/negative weight increase of initial weight on each cycle over the carbonation cycles. MnO2, Na2CO3, K2CO3 and 1-cycle CaO are removed from the analysis due to unsuccessful experiments.
After screening the absorbents, the highest conversions for CaO, Ca(OH)2, ZnO, CuO, PbO and MgO are found to be 39%, 60%, 2.3%, 19%, 17 and 5.5% respectively. Regenerability results show ZnO, CuO and PbO having stable, almost constant regenerability over the carbonation cycles while CaO, Ca(OH)2 and MgO shows better stability in regeneration in the latter carbonation cycles (i.e. 7th to 10th cycles). After performing the assessment based on conversion and regenerability of the absorbents, Ca(OH)2 looks to have the best CO2 absorption performance under the experimental conditions. Its nearest competitor is CaO, with CuO comparable to the latter. The overall reproducibility of the experiment results for the thesis project was concluded as uncertain based on contradicting results for 1-cycle CaO and ZnO. The variation of sample mass is seen to have an effect of changing the conversions of the absorbent by a small difference. However, the effect of sample mass cannot be established as insufficient data is collected from the experiments.