Characterization of selected Nigerian biomass for combustion and pyrolysis applications

Biomass is the most utilized form of renewable energy, especially in developing nations, and is a possible replacement for fossil fuel in power generation. The most commonly used method for recovering energy from biomass is combustion. Many countries are exploring the utilization of energy crops and indigenous residues to deliver sustainable sources of biomass. For these bio-resources, detailed characterization of the fuel properties is essential in order to optimize the combustion processes. In this study, some potential energy crops and woods from Nigeria, namely Terminalia superba, Gmelina arborea, Lophira alata, Nauclea diderrichii, and also one abundant agricultural residue, palm kernel expellers (PKE), were characterized for their combustion properties. Standard characterization methods such as proximate and ultimate analyses, metals analysis, and ash fusion test were used for this purpose and the results were compared with some U.K. biomass. In addition, their thermal conversion was assessed by thermogravimetric analysis and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). Finally, combustion studies were conducted by suspending single biomass particles in a methane flame to obtain information on reactivities and combustion characteristics. Results indicate that the ash fractions in the Nigerian woods were low in K, Si, and Ca, resulting in low calculated alkali indices, hence these fuels are not predicted to cause severe fouling problems. Furthermore, the analysis of the evolved product during devolatilisation from Py-GC-MS suggests that the content of oil is high in Gmelina. Finally, the results from the single particle combustion experiments revealed a longer char burn out rate for Lophira and Nauclea when compared with those of Terminalia and Gmelina

Spectroscopic analysis of bio-oil produced from sawdust of three hard wood species in Nigeria

Environmental implications of use of fossil fuel are fast becoming a global issue. The use of fossil fuel has been implicated in the accumulation of greenhouse gases, and the shift towards use of environment friendly sources of fuel is becoming popular. In this study wood waste from three tropical hardwoods were investigated for their potential to produce biofuel. Pyrolytic degradation was used to produce bio-oil from the sawdusts of Gmelina arborea, Nessogordonia papaverifera and Cordia millenii .The functional groups and various classes of chemical compositions present in thee bio-oil obtained at different temperature conditions were identified by Fourier Transform Infrared (FT-IR) analysis. The oxygen content is reflected by the presence of oxygenated fractions such as carboxylic and alcohol groups produced by pyrolysis of the cellulose, phenolic and methoxy groups produced by pyrolysis of the lignin. The bio-oil obtained showed comparable fuel properties and can be treated as moderate grade commercial fuels. In order to utilize it as commercial transportation fuel certain enhancement in properties like density and corrosiveness have to be normalize. The bio-oil obtained contains chemical compounds of varying carbon chain length from C4 - C27 and functional groups such as alkanes, alkenes, alkynes, alcohols, ketones, aldehyde, aromatic rings, amides and nitrile compounds. The thermal degradation processes (pyrolysis), may help to reduce environmental pollution, deforestation at the same time providing greater amounts of desirable, renewable fuel and chemical source.Keywords: Fossil fuel, Bio-oil, Pyrolysis, Biomass, wood residu