| 1. |
- Poornejad, Nafiseh, et al.
(författare)
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Improvement of Ethanol Production from Spruce by Solvent Pretreatment
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Lignocelluloses are abundant and inexpensive resources that can be used for production of bioethanol. However, these materials, especially softwoods, are resistant to enzymatic hydrolysis and a pretreatment process is necessary for efficient conversion to ethanol. The pretreatment is intended to render the cellulose amenable to enzymatic hydrolysis and subsequent fermentation to bioethanol. Several methods has been suggested for the pretreatment of lignocelluloses. The pretreatment with cellulose solvents are among the promising methods since they can perform in mild processing conditions. N-Methylmorpholine-N-oxide (NMMO) is among the industrial solvents which can dissolve cellulose by breaking intermolecular interactions. NMMO is nowadays used in the industrial Lyocell process, which is one of the modern and environmentally friendly industrial fiber-making technologies. It does not produce any toxic waste pollutants, and can be recovered over 98%. The pretreatment of lignocellulose by NMMO can modify the crystal structure of cellulose. In the current work a commercial grade 50% (W/W) NMMO solution was used for pretreatment of spruce. The NMMO solution was concentrated by vacuum evaporation to 85% NMMO. The pretreatment performed at 120ºC for 3 h. The pretreated wood species were then regenerated by addition of boiling distilled water, followed by vacuum filtration and washing. The pretreated and untreated spruce species were enzymatically hydrolyzed by commercial cellulase (celluclast 1.5L, Novozyme, Denmark) and Β-glucosidase (Novozyme 188, Novozyme, Denmark) at 45ºC for 96h. A thermotolerant strain of Saccharomyces cerevisiae was used for fermentation. Inoculum was aerobically cultivated at 30 °C and 120 rpm for 24 h. The enzymatic hydrolyzate was supplemented with necessary nutrient and fermented by the yeast for 24h at 30 °C and 120 rpm. The liquid samples were analyzed by HPLC. The results showed that the yield of ethanol increased from 7.2 g/g to 77 g/g, when the wood treated with the solvent. Formation of glycerol and other metabolites were also detected and discussed. It can be concluded that the method can be a promising alternative for pretreatment of softwoods for bioethanol production.
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| 2. |
- Salehi, Hamid, et al.
(författare)
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The role of particle size and other properties on silo discharge behaviour of chipped wood biomass
- 2024
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Ingår i: Powder Technology. - : Elsevier. - 0032-5910 .- 1873-328X. ; 432
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Tidskriftsartikel (refereegranskat)abstract
- To achieve net-zero carbon emissions by 2050, the UK government emphasizes the pivotal role of sustainable bioenergy in electricity, transportation, and heating. However, challenges persist in handling biomass particulate solids in production facilities, leading to economic impacts. This study investigates the flow characteristics of stemwood chips from four tree species using a novel drum chipper. Experimental analyses include bulk density measurements, silo discharge studies, biomass flow property assessments, and wall friction measurements. Comparative analyses are performed using Jenike's procedure for building wedge-shaped silos, with a focus on predicting the critical opening size to prevent arching. Additionally, the paper delves into the creation of statistical models aimed at identifying key factors influencing the flow behaviour during silo discharge. Emphasis is placed on understanding potential discrepancies between theoretical predictions and experimental results concerning critical silo openings for arch-free discharge. The results contribute to understanding the factors influencing the flow behaviour of wood chips, informing silo design considerations. Our findings suggest limitations in applying traditional silo design methods, urging further research for more accurate predictions.
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