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dc.contributor.advisorStrydom, C.A.
dc.contributor.advisorBunt, J.R.
dc.contributor.authorCollins, Anna Catharina
dc.date.accessioned2014-07-09T06:44:18Z
dc.date.available2014-07-09T06:44:18Z
dc.date.issued2014
dc.identifier.urihttp://hdl.handle.net/10394/10837
dc.descriptionMSc (Chemistry), North-West University, Potchefstroom Campus, 2014en_US
dc.description.abstractAlkali compounds were added to a South African coal with a high swelling propensity and the behaviour of the blends were investigated. A vitrinite-rich bituminous coal from the Tshikondeni coal mine in the Limpopo province of South Africa was used. To reduce the influence of the minerals in the coal, the coal was partially demineralized by leaching with HCl and HF. The ash content of the coal sample was successfully reduced from 17.7% to 0.6%. KOH, KCl, K2CO3 and KCH3CO2 were then added to the demineralized coal in mass percentages of 1%, 4%, 5% and 10%. The free swelling indices (FSI) of the blends were determined and the samples were subjected to acquisition of TMA and TG-MS data. Addition of these potassium compounds to the demineralized coal reduced the swelling of the vitrinite-rich coal. From the free swelling indices of the various mixtures, it was concluded that the potassium compounds reduce the swelling of the coal in the following order of decreasing impact: KCH3CO2 > KOH > K2CO3 > KCl. From dilatometry experiments done on the blends with the 10% addition of potassium compounds, it was seen that with the addition of potassium compounds to the demineralized coal, a reduction in dilatation volume was obtained. The influence of the potassium compound in decreasing order: K2CO3> KOH> KCH3CO2> KCl. An increase in the softening temperature was observed for the demineralized coal-alkali blends. Thermogravimetric analyses were performed on the demineralized coal-potassium blended samples (<75 μm). These samples were pyrolyzed under a nitrogen atmosphere to a maximum temperature of 1200 °C using a heating rate of 10 °C/min. The relative reactivity for each of the blends with the different wt% addition was determined. From these results it was seen that KCH3CO2 increased the relative reactivity, whereas the KOH, KCl and K2CO3 showed an inhibiting influence. The attached mass spectrometer provided information on the low molecular mass gaseous products formed in the various temperature ranges as the thermal treatment proceeded. From the mass spectroscopy results, it was found that the potassium compounds decreased the temperature at which maximum evolution of H2 takes place. Thermomechanical analyses were performed on the 10 wt% addition of the potassium compounds to the demineralized coal. During TMA analyses, the sample was heated to 1000 °C using a heating rate of 10 °C/min. From the TMA result obtained it was clear that the addition of KCl did not have an influence on the swelling of the demineralized coal. All results are discussed.en_US
dc.language.isoenen_US
dc.subjectSouth African coalen_US
dc.subjectSwellingen_US
dc.subjectDilatometryen_US
dc.subjectTMAen_US
dc.subjectPlastic propertiesen_US
dc.subjectPyrolysisen_US
dc.subjectPotassium compoundsen_US
dc.subjectSuid-Afrikaanse steenkoolen_US
dc.subjectDilatometrieen_US
dc.subjectPlastiese eienskappeen_US
dc.subjectPiroliseen_US
dc.subjectKalium verbindingsen_US
dc.titleThe influence of potassium and calcium species on the swelling and reactivity of a high–swelling South African coalen
dc.typeThesisen_US
dc.description.thesistypeMastersen_US
dc.contributor.researchID20682972 - Strydom, Christiena Adriana (Supervisor)
dc.contributor.researchID20164200 - Bunt, John Reginald (Supervisor)


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