Extraction of Hemicellulose from Acacia Wood via Autohydrolysis and Ethanol Precipitation

Isolation and utilization of hemicellulose are important processes in the pulp mill-based biorefinery. Considering the potential end use of the hemicellulose,this study investigated the concentration of monomeric and oligomeric sugars in the hydrolysate derived from autohydrolysis of acacia wood and the obtainment of these sugars via ethanol precipitation. The rate of generation of monomers and oligomers increased dramatically with an increase of the temperature from 160℃ to 180℃. The maximum content of oligomers and total sugars was achieved under conditions of 180℃ and 10 min,170℃ and 85 min,respectively. Interestingly,the maximum yield of hemicellulose via ethanol precipitation was achieved in a much shorter time,compared with the maximum yield of oligomer from the hydrolysate by autohydrolysis. A 6. 66 g / L quantity of hemicellulose was obtained by intensifying the conditions of ethanol precipitation. The hemicellulose characteristics were analyzed by Fourier transform infrared,nuclear magnetic resonance,and ultraviolet spectroscopy,and the molecular weight was determined by gel permeation chromatography and thermal analysis.

Energy and Autohydrolysis By-Products from Industrial Crops

The world is experiencing a growing shortage of raw materials which is especially severe in the energy sector and being worsened by the unfavorable environmental impact of a consumerist cultttre revolving around the exploitation of non-renewable resources. In this work, the calorific value and chemical composition of liquors resulting from the autohydrolysis of six different lignocellulosic materials was determined （Eucalyptus globulus, Arundo donax, Leucaena diversifolia, Paulownia fortunei, Sunflower stalks and Chamaecytisus proliferus） and was assessed for the obtainment of energy, sugars and other chemical products by using of integral fractionation based on autohydrolysis. Autohydrolysis processes have been considered interesting in the case of timber species studied compared with herbaceous species with variations in the extraction of the xylan fraction at 180℃ between 19.68% for Eucalyptus globulus and 36.79% for Leucaena diversifolia and 200℃ between 57.86% for Paulawniafortunei and 79.13 % for Chamaecytisusproliferus. In general, all materials show a solid fraction ＂more energy＂ from the hydrolysis to 200℃ than 180℃ and raw materials. It is interesting as the potential economy valuation of the liquid fractions of the hydrolysis, the solid waste recovery present more energetic profitability.

Autohydrolyzed Low-Cost Biomass and Adsorbent Aging

Autohydrolysis or self-hydrolysis or hydrothermal treatment of lignocellulosic materials like sawdust and straw is already used in bioethanol industry for water soluble fermentable sugars production.The main idea in this paper is the use of the autohydrolysis and other thermochemical treatments’solid residue as an adsorbent.In this study continuous fixed-bed-column systems were investigated.Continue-flow experiments were carried out on stainless steel columns with dimensions 15×2.5 and 25×2.5 cm.In chemical processing,a packed bed is a hollow tube,pipe,or other vessel that is filled with a packing material.