engleski

Dilute alkali pre-treatment of wheat straw in high-pressure reactor

Waste lignocellulosic raw materials are by- products of agriculture, forest and wood industry, and represent a valuable alternative for the production of biofuels and different biochemicals. Since lignocellulose is highly resistant to microbial degradation, the aim of this work was to conduct alkali pre-treatment of wheat straw and to determine the optimum conditions for wheat straw pre-treatment with sodium hydroxide solution. Pretreatment of wheat straw was performed in high-pressure reactor. The reactor was filled with 500 g of wheat straw (% w/w ; reduced in size to 5 mm pieces) and 10 L of 2 % (w/w) sodium hydroxide solution and homogenized. Pre-treatment was performed at 120, 160, 180 and 210°C and residence time of 1, 10 and 20 minutes. After pretreatment two phases were obtained, liquid and solid phase (pre-treated wheat straw). Composition of these phases was determined according to NREL method (Sluiter et al., 2011). Glucan content in the pretreated wheat straw ranged from 23.5 % to 86.1 %, while xylan and arabinan content ranged from 1.6 % to 24.8 % and 0.00 % to 11.4 %, respectively. Also, in these pretreatments 55.8 % to 97.1 % of lignin was removed. The highest glucan content (86.1 %) in solid phase was determined at 210°C and a residence time of 10 minutes while maximum lignin removal (97.1 %) in contrast to wheat straw composition was determined at 210°C and 20 minutes residence time.

Wheat straw, dilute alkali pre-treatment, high-pressure reactor, different temperatures, deferent residence times

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