Bio-Chemicals Derived from Waste: Building on the Concept of a Bio-Refinery

Abstract

The work presented here has looked into the thermal-conversion of wheat and barley spent grains (SG). Wheat fermentation was carried in the laboratory to get a mashed product while barley grain residues were sourced from a local brewing company. Pyrolysis carried at 460, 520 and 540 oC at ambient conditions of pressure in a bench scale fluidized bed reactor resulted in producing bio-oil, charcoal and non-condensable gases. These products were characterized by using the Gas Chromatography Mass Spectrometry (GC-MS), Differential Thermo-glavemetric Analysis (DTG), Elemental Analyzer (E.A) and a Bomb Calorimeter. The final pyrolysis product analysis revealed that the bio-oil production yields and Higher Heating Value (HHV) largely depended on the pyrolysis temperature and the sample type. In comparison with original raw grain samples, the analysis of thermally treated (pyrolysis) spent grains revealed the presence of high carbon and low oxygen contents. Results gathered in this work have shown that high bio-crude-oil production yields can be obtained at 520 oC (53 and 37wt% bio-oil from wheat and barley SG). Pyrolysis of wheat and barley SG resulted in giving a Higher Heating Value (HHV) of 21.80 and 21.86 MJ/kg at 540 and 460oC, which is considerably more in comparison to their virgin counterparts. This suggested route thus has a potential for further up-gradation of waste bio-mass for use as an intermediate fuel or as a raw material source for producing other bio-chemicals.