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Hydrogen rich syngas from the pyrolysis and gasification of solid waste and biomass

Efika, Emmanuel Chidi (2013) Hydrogen rich syngas from the pyrolysis and gasification of solid waste and biomass. PhD thesis, University of Leeds.

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Abstract

Biomass and wastes are potential resources for the production of renewable hydrogen, synthetic fuels, chemicals and energy via pyrolysis and gasification. Waste biomass and refuse derived fuel (RDF), and their single components were investigated for pyrolysis to produce a hydrogen rich syngas with a bench scale fixed bed reactor. The samples were pyrolysed at different temperatures, heating rates and particle sizes to recover syngas, oil and char products. The waste biomass was investigated for steam pyrolysisgasification in a continuous screw kiln reactor to produce hydrogen. The samples were gasified at different temperatures, steam/biomass ratios, and in the presence of nickel catalysts. The effects of nickel loading on the catalyst, the catalyst/waste biomass ratio, the effects of different metal additives and the effect of in-situ CO2 capture were also investigated for hydrogen production and resistance to catalyst deactivation by coking. A commercial scale pyrolysis reactor was studied for the pyrolysis of real world wastes. FTIR and GC/MS analysis of the oils from the pyrolysis of waste biomass, RDF and their single components indicated that the oil product from high heating rate pyrolysis contained mostly aromatics and alkenes, while that from slow heating rate contained mostly oxygenates, alkanes and alkenes. Gaseous products from the waste biomass, RDF and their single components contained mostly CO, CO2, H2, CH4 and C2 – C4 gases. Increasing the pyrolysis temperature and heating rate both resulted in an increase in gas and hydrogen production while reducing the oil and solid char yields. The gas yield and hydrogen yield were increased with increasing nickel loading and catalyst to waste biomass ratio during steam pyrolysisgasification. The lowest tar yield of 0.01g of tar per m3 of gas and highest hydrogen yield of 55 vol% were achieved at catalyst/waste biomass ratio of 2. Ce and La promoted catalysts showed improved catalyst resistance to coking and increased hydrogen yield. CaO resulted in in-situ capture of CO2 however the H2 yield was not increased due to the deactivation of CaO by tar in. The commercial scale system resulted in conversion of wastes to syngas, oil and char however results were not comparable to laboratory scale results due to limitations in the commercial scale process.

Item Type: Thesis (PhD)
ISBN: 987-0-85731-480-2
Academic Units: The University of Leeds > Faculty of Engineering (Leeds) > School of Chemical and Process Engineering (Leeds)
Depositing User: Repository Administrator
Date Deposited: 07 Jan 2014 09:53
Last Modified: 01 Oct 2018 00:18
URI: http://etheses.whiterose.ac.uk/id/eprint/4943

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