Tarımsal atık olan mısır sömeğinden metan üretiminin ortak çürütme ve ön işlem ile geliştirilmesinin incelenmesi

In recent years, the renewable energy requirement is increased with the population increase and reduction of fossil fuel resources. In terms of biomass energy, corn waste constitutes the highest portion (33%) among crop wastes in the world. Thus, corncob, which is a corn waste and also non-food waste, has a great potential as a renewable energy source in the country. In this thesis study, the biochemical methane potential (BMP) of corncob (raw CC) was investigated initially and assessed by adopting co-digestion with feed (chicken manure (83%) and poppy (17%)), digestate or post-digestate and a pretreatment method, alkaline hydrothermal pretreatment at 240℃ (AHP_240). BMP of corncob was 103 mL CH4/g VSadded, and the highest synergistic effect was observed in Raw CC+Digestate reactors with 172 mL CH4/g VSadded. After AHP_240 method was applied, although sCOD of AHP_240 CC increased 17 times compared to Raw CC, methane yield of both AHP_240 CC and its co-digestion reactors did not significantly improve. After that, hydrothermal, alkaline and alkaline hydrothermal pretreatment methods were applied on Raw CC by using various temperatures, namely 150℃, 180℃ and 210℃ for their optimization. The hydrothermal pretreated corncob (HP CC) had 55-61% higher methane yield than Raw CC and there was no statistically significant difference among methane yields obtained for different temperatures studied. Thus, HP_150 method was selected as the optimum pretreatment method. Lastly, raw CC or hydrothermal pretreated corncob at 150 ℃ (HP_150 CC) were used as substrates with digestate in semi-continuous co-digestion reactors to investigate the optimum operational conditions, i.e., hydraulic retention time (HRT) and organic loading rate (OLR), leading to the maximum methane production. The highest methane yield of HP_150 CC and Digestate reactor was 392 mL CH4/g VSadded at an HRT of 10 days and OLR of 4.5 g VS/L.d. Raw CC apparently requires more than 15 days of HRT for higher solubilization. But, when HP_150 method is applied, HRT of 10 days seems to be profitable. This means smaller volume and lower capital cost for biogas plant. The use of HP_150 CC with Digestate in semi continuous reactors seems to be promising and feasible for methane production in large-scale biogas plant.