Paper Title
Performance of Zeolite ZSM-5 Synthesised from South African Fly Ash in The Conversion of Methanol to Hydrocarbons

Abstract
This study provides a method of using South African fly ash (FA) as a cheap source of Si and Al by extracting Silica from a fused fly ash filtrate with concentrated sulphuric acid (99 %), and then using the extract to synthesise zeolite ZSM-5 products. This approach raised the Si/Al ratio that was 1.97 in the as-received fly ash to 10.8 in the silica extract. Because the obtained Si/Al ratio in the fused fly ash extract was still not deemed siliceous enough to synthesise crystalline zeolite ZSM-5 samples, therefore the addition of small amounts of fumed Si (0.000, 0.250, 0.375 g) into the synthesis gel was investigated. The synthesised zeolite ZSM-5 samples were then characterised using the following methods: XRD, SEM/EDS, FTIR, NMR and N2 BET. It was noticed that the addition of small amounts of fumed silica influenced the Si/Al ratio, phase purity, morphology, crystal size, N2 BET surface area, and the catalytic properties of the synthesised ZSM-5 products. The XRD spectra of zeolite ZSM-5 that was synthesised without the addition of fumed silica (0.00 g) showed that the catalyst was partially crystalline with a phase purity of 9 % while a phase purity of 95 or 94 % was obtained when the Si/Al ratio increased from 32 to 41 respectively. The Methanol to hydrocarbon reaction was used to test the performance of the synthesised ZSM-5 catalysts with reaction parameters that include: WHSV-1 = 2, temperatures (350 oC and 400 oC) and atmospheric pressure. The H-ZSM-5 catalyst synthesised with a Si/Al of 32 showed the highest conversion of methanol and yield of hydrocarbon fuels such as ethylene (C2), propylene (C3), and butene (C4) that was benchmarked against the commercial H-ZSM-5 Keywords - Coal fly ash, Acid Treatment, Zeolite ZSM-5, Fused Fly Ash Extract, TETRAPROPYLAMMONIUM Bromide, Methanol-to-hydrocarbons (MTH) Reaction.