Thesis
Pretreatment method using a mixture of ammonium carbonate and ammonium hydroxide to enhance the CH₄ generation of oil palm empty fruit bunch (Op-EFB)
Washington State University
Master of Science (MS), Washington State University
05/2016
Handle:
https://hdl.handle.net/2376/101821
Abstract
Pretreating lignocellulose for subsequent conversion into chemical intermediates and fuels remains a challenge due to the high cost of the process. Therefore, it is necessary to find new low-cost pretreatment methods with sufficient effects on the structure of the plant cell walls to reduce their recalcitrance. Alkaline pretreatment of biomass for CH4 production through anaerobic digestion (AD) can be performed under low severity conditions, leading to in lower costs. In this study, the use of a mixture of ammonium carbonate ((NH4) 2CO3) and ammonium hydroxide (NH4OH) was evaluated for its ability to pretreat oil palm empty fruit bunch (OPEFB). These ammonia-based chemicals can deconstruct silicified cuticle layer of the biomass and remove silica embedded on the OP-EFB. The correlation between delignification, hemicellulosic sugar solubilization (total of arabinose, xylose, and galactose present in the liquid fraction compared to the total dry weight arabinose, xylose, and galactose in the untreated OPEFB), ash removal (as a representative of silica removal), and pretreatment effectiveness for CH4 production in alkaline pretreatment was examined. Microscopy observation was also performed to examine the morphological changes occurred during pretreatment. Results show that the use of 10% (w/v) mixture of 1:1 (NH4) 2CO3 5% (w/v) and NH4OH 5% (w/v) resulted in lignin removal of 36.47%, 82.42% ash removal, and hemicellulose solubilization of 5.54% w/w from OP-EFB after 24 h pretreatment. Further pretreatment after 24 h resulted in insignificant changes in hemicellulose content. The 24 h pretreatment led to a maximum methane yields of 426.51 ml CH4/g VS, which was approximately 22.7% more than the yield from untreated OP-EFB. The improvement caused by this low severe pretreatment process is beneficial in the implementation especially considering the low installation and operation costs. The results from microscopy observation also showed how silica removal by the pretreatment method played significant roles to form the silica crater that is less recalcitrant to become a starting point of the digestion process in the AD's hydrolytic stage.
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Details
- Title
- Pretreatment method using a mixture of ammonium carbonate and ammonium hydroxide to enhance the CH₄ generation of oil palm empty fruit bunch (Op-EFB)
- Creators
- Iin Parlina
- Contributors
- Shulin Chen (Chair)Bin Yang (Committee Member) - Washington State University, Biological Systems Engineering, Department ofPius M Ndegwa (Committee Member) - Washington State University, Biological Systems Engineering, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 61
- Identifiers
- 99900525164101842
- Language
- English
- Resource Type
- Thesis