Summary: | 碩士 === 國立交通大學 === 分子醫學與生物工程研究所 === 106 === As a lignocellulosic crop, napiergrass is abundant in cellulose and hemicellulose. It has been considered as a potential energy crops due to its short growing cycle, low-cost for planting and is able to grow on infertile land. To enhance the microbial’s conversion efficiency to bio-ethanol, it is commonly pretreated by dilute-acid steam explosion (A-SE) and steam explosion(SE) to destroy its rigid structure. However, it’s not suitable for anaerobic digestion to produce biogas because of the low pH value and high C/N ratio (>45) after pretreatment. In this study, we investigate the biogas production efficiency by adjusting the pH value and C/N ratio, and we use swine wastewater to co-digest with the napiergrass to evaluate the feasibility of napiergrass as an energy crop.
The results showed that raw napiergrass contained 28% of hemicellulose and 70% which can be converted to sugar through the A-SE and SE pretreatment. In batch experiments, we adjusted the pH value to 5 and C/N ratio to 40 of A-SE napiergrass and found that its biogas production was 245 and 244 mL/g TS; The efficiency of swine wastewater co-digest with 1% dry weight of A-SE and SE napiergrass were 271 and 220 mL/g TS respectively. For continuous co-digestion experiment, a lab-scale continuous anaerobic reactor was used to investigate the biogas production efficiency of co-digestion. The results indicated that A-SE and SE could produce 347 and 260 mL/g TS respectively. The A-SE napiergrass showed the most optimum efficiency and has the best increase of efficiency compared with the batch experiment. In conclusion, we found that napiergrass was a good biogas production crop and it could be a suitable energy crop.
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