Effect of pre-treatment conditions on the analytical pyrolysis products from birch wood lignocellulose

摘要

The production of valuable chemicals from biomass is an integral part in the way to substitute fossil raw materials and promote the development of a bio-based society. For different reasons, progress in this field today is not sufficient, especially concerning the pyrolytic processing methods. Pyrolysis of lignocellulosic (LC) materials like wood is a complex process determined by three different main constituents, namely, hemicelluloses, cellulose and lignin, producing diverse decomposition products. For this reason, it is an interesting approach to conduct the pre-treatment of wood for obtaining raw materials, favourable for producing one or several compounds in excess. Birch (Betula pendula) wood chips were treated with 3% H_2SO_4 from wood oven dry mass and hydrolysed in two different ways. The effect of the pre-treatment on the yield and composition of the analytical pyrolysis products was investigated by the pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) method. The yield of the pyrolysis liquid products, especially levoglucosan, strongly depended on the temperature and method of birch wood hydrolysis. More neutral washing pH favoured the arising of levoglucosan, but decreased the yield of furfural and its derivatives, 1,6-anhydro-β-D-glucofuranose and l,4:3,6-dianhydro-α-D-glucopyranose. LC pre-treatment conditions have a significant effect on the composition of pyrolysis liquid products and, changing the pre-treatment parameters, can be used to increase the yield of valuable products.