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Miscanthus × giganteus was subjected to pre-treatment with deionised water, hydrochloric acid or Triton X-100 surfactant, and subsequently fast pyrolysed in a fluidised bed reactor at 535 °C to obtain bio-oil. Triton X-100 surfactant was identified as a promising pre-treatment medium for removal of inorganic matter because its physicochemical nature was expected to mobilise inorganic matter in the biomass matrix. The influence of different concentrations of Triton X-100 pre-treatment solutions on the quality of bio-oil produced from fast pyrolysis was studied, as defined by a single phase bio-oil, viscosity index and water content index. The highest concentration of Triton X-100 surfactant produced the best quality bio-oil with high organic yield and low reaction water content. The calculated viscosity index from the accelerated ageing test showed that bio-oil stability improved as the concentration of Triton X-100 increased. [ABSTRACT FROM AUTHOR]

Abstract: The research investigates the fuel property variations associated with the time of harvest and the duration of storage of Miscanthus x giganteus over a one year period. The crop has been harvested at three different times: early (September 2009), conventional (April 2010) and late (June 2010). Once harvested the crop was baled and stored. Biomass properties of samples taken from different storage zones were compared. The thermochemical properties have been investigated using a range of analytical equipment including thermogravimetric analysis (TGA) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). In addition, bio-oil has been produced from the early, conventional and late harvest using a laboratory scale (300 g h−1) fast pyrolysis unit. The potential organic liquid yield (on dry basis, also excluding the reaction water generated) based on the laboratory fast pyrolysis processing undertaken in this study, was found to vary between 2.82 and 3.18 dry t ha−1 for the early and the late harvest respectively. The bio-oil organic yield was reduced by approximately 11% (0.36 t ha−1) between the early and the late harvest. Char yield was also reduced by approximately 18% (0.61 t ha−1). The highest gas yield (18.03%-1.60 t ha−1) was observed for the conventional harvest. Gas chromatography-mass spectrometry (GC-MS) analysis of the bio-oil shows that levoglucosan, methylbenzaldehyde and 1,2-benzenediol all increase as a consequence of delayed harvest. It was also observed that by delaying the harvest time the O:C atomic ratio is reduced and a more carbonaceous feedstock is produced. [Copyright &y& Elsevier]

Abstract: The aim of this study is to characterise and compare fast pyrolysis product yields from straw, high yielding perennial grasses and hardwoods. Feedstocks selected for this study include: wheat straw (Triticum aestivum), switch grass (Panicum virgatum), miscanthus (Miscanthus x giganteus), willow short rotation coppice (Salix viminalis) and beech wood (Fagus sylvatica). The experimental work is divided into two sections: analytical (TGA and Py-GC–MS) and laboratory scale processing using a continuously fed bubbling fluidized bed reactor with a capacity of up to 1kg/h. Pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS) has been used to quantify pyrolysis products and simulate fast pyrolysis heating rates, in order to study potential key light and medium volatile decomposition products found in these feedstocks. Py-GC–MS quantification results show that the highest yields of furfural (0.57wt.%), 2-furanmethanol (0.18wt.%), levoglucosan (0.73wt.%), 1,2-benzenediol (0.27wt.%) and 2-methoxy-4-vinylphenol (0.38wt.%) were found in switch grass, and that willow SRC produced the highest yield of phenol (0.33wt.%). The bio-oil higher heating value was highest for switch grass (22.3MJ/kg). Water content within the bio-oil is highest in the straw and perennial grasses and lowest in the hardwood willow SRC. The high bio-oil and char heating value and low water content found in willow SRC, makes this crop an attractive energy feedstock for fast pyrolysis processing, if the associated production costs and harvest yields can be maintained at current reported values. The bio-oil from switch grass has the highest potential for the production of high value chemicals. [Copyright &y& Elsevier]

Abstract: The main aim of the work is to investigate sequential pyrolysis of willow SRC using two different heating rates (25 and 1500°C/min) between 320 and 520°C. Thermogravimetric analysis (TGA) and pyrolysis – gas chromatography – mass spectroscopy (Py–GC–MS) have been used for this analysis. In addition, laboratory scale processing has been undertaken to compare product distribution from fast and slow pyrolysis at 500°C. Fast pyrolysis was carried out using a 1kg/h continuous bubbling fluidized bed reactor, and slow pyrolysis using a 100g batch reactor. Findings from this study show that heating rate and pyrolysis temperatures have a significant influence on the chemical content of decomposition products. From the analytical sequential pyrolysis, an inverse relationship was seen between the total yield of furfural (at high heating rates) and 2-furanmethanol (at low heating rates). The total yield of 1,2-dihydroxybenzene (catechol) was found to be significant higher at low heating rates. The intermediates of catechol, 2-methoxy-4-(2-propenyl)phenol (eugenol); 2-methoxyphenol (guaiacol); 4-Hydroxy-3,5-dimethoxybenzaldehyde (syringaldehyde) and 4-hydroxy-3-methoxybenzaldehyde (vanillin), were found to be highest at high heating rates. It was also found that laboratory scale processing alters the pyrolysis bio-oil chemical composition, and the proportions of pyrolysis product yields. The GC–MS/FID analysis of fast and slow pyrolysis bio-oils reveals significant differences. [Copyright &y& Elsevier]

Abstract: An international study of fast pyrolysis of lignin was undertaken. Fourteen laboratories in eight different countries contributed. Two lignin samples were distributed to the laboratories for analysis and bench-scale process testing in fast pyrolysis. Analyses included proximate and ultimate analysis, thermogravimetric analysis, and analytical pyrolysis. The bench-scale test included bubbling fluidized-bed reactors and entrained-flow systems. Based on the results of the various analyses and tests it was concluded that a concentrated lignin (estimated at about 50% lignin and 50% cellulose) behaved like a typical biomass, producing a slightly reduced amount of a fairly typical bio-oil, while a purified lignin material was difficult to process in the fast pyrolysis reactors and produced a much lower amount of a different kind of bio-oil. It was concluded that for highly concentrated lignin feedstocks new reactor designs will be required other than the typical fluidized-bed fast pyrolysis systems. [Copyright &y& Elsevier]

Abstract: In this study the impact of senescence and harvest time in Miscanthus on the quality of fast pyrolysis liquid (bio-oil) was investigated. Bio-oil was produced using a 1kgh−1 fast pyrolysis reactor to obtain a quantity of bio-oil comparable with existing industrial reactors. Bio-oil stability was measured using viscosity, water content, pH and heating value changes under specific conditions. Plant developmental characteristics were significantly different (P ⩽0.05) between all harvest points. The stage of crop senescence was correlated with nutrient remobilisation (N, P, K; r2 =0.9043, r2 =0.9920, r2 =0.9977 respectively) and affected bio-oil quality. Harvest time and senescence impacted bio-oil quality and stability. For fast pyrolysis processing of Miscanthus, the harvest time of Miscanthus can be extended to cover a wider harvest window whilst still maintaining bio-oil quality but this may impact mineral depletion in, and long term sustainability of, the crop unless these minerals can be recycled. [Copyright &y& Elsevier]