Papers by Tony Bridgwater
Applied Geochemistry, 2017
Metal smelter activities have contaminated approximately 700 km 2 of the Campine region in Belgiu... more Metal smelter activities have contaminated approximately 700 km 2 of the Campine region in Belgium and The Netherlands. This work aimed to assess the effectiveness of biochar added to this soil using compost, peat or lime as a reference. Amendments were mixed with the contaminated soil at a 2 or 4% ratio (w:w) and equilibrated for up to 44 weeks. Treatment with biochar released significantly lower concentrations of Cd in the soil solution than compost or peat. In comparison to the blanks, soil solution concentrations of Cd were reduced 67% on average for the 4% biochar treatment and increased 30% and 231% for the 4% compost and 4% peat treatments, respectively. The lime treatment was equally effective as the biochar in reducing Cd concentrations. Similar trends were observed when conducting consecutive CaCl 2 extractions. However, pH-stat leaching tests showed biochar and the other organic amendments to be more effective than lime in retaining Cd from the solution. The combined effect of pH and metal complexation capacity of added biochar resulted in an effective reduction in soluble Cd concentrations that lasted longer than when lime, compost or peat are used.
Molecular Catalysis, 2021
Biomass-derived carboxylic acids (e.g. acetic acid AcOH and formic acid FA) are a green and low-c... more Biomass-derived carboxylic acids (e.g. acetic acid AcOH and formic acid FA) are a green and low-cost hydrogen source to replace hazardous H 2 gas in in-situ hydrogenation processes. To date, bio-acids dehydrogenation has been mainly conducted using noble metal catalysts which would negatively impact the process economy, thus development of efficient non-noble metal catalysts for this purpose is highly desirable. In this study, the performance of transition metals supported on nitrogen doped carbon nanotubes was thoroughly evaluated by computational modelling based on Density Functional Theory (DFT). Results revealed that, out of the 10 selected transition metal candidates, molybdenum (Mo) was most active for binding AcOH and a combination of Mo and nitrogen doping significantly enhanced binding to the carboxylic acid molecules compared to pristine carbon nanotubes (CNTs). The newly designed Mo/N-CNT catalysts considerably facilitated the bio-acids decomposition compared to the non-catalytic scenarios by lowering energy barriers. FA distinctly outperformed AcOH in hydrogen donation over Mo/N-CNT catalysts, through its spontaneous cleavage leading to facile hydrogen donation.
Bioresource Technology, Feb 1, 2011
Different species and genotypes of Miscanthus were analysed to determine the influence of genotyp... more Different species and genotypes of Miscanthus were analysed to determine the influence of genotypic variation and harvest time on cell wall composition and the products which may be refined via pyrolysis. Wet chemical, thermo-gravimetric (TGA) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) methods were used to identify the main pyrolysis products and determine the extent to which genotypic differences in cell wall composition influence the range and yield of pyrolysis products. Significant genotypic variation in composition was identified between species and genotypes, and a clear relationship was observed between the biomass composition, yields of pyrolysis products, and the composition of the volatile fraction. Results indicated that genotypes other than the commercially cultivated Miscanthus x giganteus may have greater potential for use in bio-refining of fuels and chemicals and several genotypes were identified as excellent candidates for the generation of genetic mapping families and the breeding of new genotypes with improved conversion quality characteristics.
Energy & Fuels, Feb 22, 2010
ABSTRACT The paper presents a comparison between the different drag models for granular flows dev... more ABSTRACT The paper presents a comparison between the different drag models for granular flows developed in the literature and the effect of each one of them on the fast pyrolysis of wood. The process takes place on an 100 g/h lab scale bubbling fluidized bed reactor located at Aston University. FLUENT 6.3 is used as the modeling framework of the fluidized bed hydrodynamics, while the fast pyrolysis of the discrete wood particles is incorporated as an external user defined function (UDF) hooked to FLUENT’s main code structure. Three different drag models for granular flows are compared, namely the Gidaspow, Syamlal O’Brien, and Wen-Yu, already incorporated in FLUENT’s main code, and their impact on particle trajectory, heat transfer, degradation rate, product yields, and char residence time is quantified. The Eulerian approach is used to model the bubbling behavior of the sand, which is treated as a continuum. Biomass reaction kinetics is modeled according to the literature using a two-stage, semiglobal model that takes into account secondary reactions.
Applied Energy, Jun 1, 2022
Applied Catalysis A-general, Sep 1, 2019
Highlights • Hydrogen donation in catalytic decomposition of bio-acids and H 2 was investigated. ... more Highlights • Hydrogen donation in catalytic decomposition of bio-acids and H 2 was investigated. • Ten transition metals were tested for bio-acid adsorption. • Electron density difference was analysed to elucidate interface interaction. • Mo showed good effects in facilitating the decomposition of bio-acids. • AcOH had good potential as an alternative hydrogen donor compound over Mo (110).
Environmental progress & sustainable energy, Apr 5, 2012
A comprehensive examination is made of the characteristics and quality requirements of bio-oil fr... more A comprehensive examination is made of the characteristics and quality requirements of bio-oil from fast pyrolysis of biomass. An appreciation of the potential for bio-oil to meet a broad spectrum of applications in renewable energy has led to a significantly increased R&D activity that has focused on addressing liquid quality issues both for direct use for heat and power and indirect use for biofuels and green chemicals. This increased activity is evident in North America, Europe, and Asia with many new entrants as well as expansion of existing activities. The only disappointment is the more limited industrial development and also deployment of fast pyrolysis processes that are necessary to provide the basic bio-oil raw material. 2012 American Institute of Chemical
A systematic survey of the possible methods of chemical extraction of iron by chloride formation ... more A systematic survey of the possible methods of chemical extraction of iron by chloride formation has been presented and supported by a comparable study of :feedstocks, products and markets. The generation and evaluation of alternative processes was carried out by the technique of morphological analysis vihich was exploited by way of a computer program. The final choice was related to technical feasibility and economic viability, particularly capital cost requirements and developments were made in an estimating procedure for hydrometallurgjcal processes which have general applications. The systematic exploration included the compilation of relevant data, and this indicated a need.to investigate precipitative hydrolysis or aqueous ferric chloride. Arising from this study, two novel hydrometallurgical processes for manufacturing iron powder are proposed and experimental work was undertaken in the following .areas to demonstrate feasibility and obtain basic data for design purposes: (1)...
This paper presents the main results of the French project PRECOND which aimed at evaluating the ... more This paper presents the main results of the French project PRECOND which aimed at evaluating the technical & economical viability of fast pyrolysis as biomass preconditioning route for the following utilizations: gasification and FT-synthesis into synthetic transport bio-fuels; petroleum co-refining into transport bio-fuels; combustion for CHP. First, the expected bio-oil specifications have been assessed according to the utilization. A bench scale fluidized bed, identified as the reference technology, was constructed and operated on different biomasses. The methods for physico-chemical characterization of bio-oils were characterized were evaluated, as well as their stability and rheological behaviour. Besides, a new model of the reactor was set-up, resulting in good predictions of the experimental mass balances. Finally, a techno-economical assessment of the whole preconditioning route has led to evaluation of bio-oil production costs and the consequence on the utilizations consid...
Perennial grasses offer potential for providing a year round supply of low cost biomass when grow... more Perennial grasses offer potential for providing a year round supply of low cost biomass when grown in southern European conditions. Four crops, Giant reed, Cardoon thistle, Miscanthus and Switchgrass have been assessed for ash content, composition and melting behaviour. Ash content for all four crops is high compared to wood and initial data suggests soil contamination is a major contributor. All crops have naturally high levels of potassium and chlorine but it is notable that Cardoon also has high levels of calcium and sodium. Ash melting temperatures are between 1000°C and 1160°C in oxidizing conditions except for Cardoon where some samples have sintered at ca 750°C. Pilot scale combustion tests on Giant reed, Miscanthus and Switchgrass at Graz showed slag accumulation on the grate, high rates of fouling and high emissions. Corrosion problems would also be expected. Preliminary fluidized bed gasification of Switchgrass was successful, however testing on Cardoon was abandoned due t...
Waste and Biomass Valorization, 2020
This study aims to compare the potential of Virginia mallow to other high yielding perennial gras... more This study aims to compare the potential of Virginia mallow to other high yielding perennial grasses and hardwoods by characterising and comparing fast pyrolysis product yields. Feedstocks selected for this study include miscanthus (Miscanthus x giganteus), Virginia mallow (Sida hermaphrodita), willow short rotation coppice (SRC) (Salix viminalis) and oak (Quercus robur). The experimental work was split into two sections: analytical (Py–GC–MS) and laboratory-scale processing using a 300 g h−1 continuous bubbling fluidised bed reactor. Pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) has been used to quantify pyrolysis products from these feedstocks by simulating fast pyrolysis heating rates using a CDS 5200 pyrolyser closed coupled to a PerkinElmer Clarus 680 GC–MS. High bio-oil yields were achieved for Virginia mallow, willow SRC and oak (65.36, 62.55 and 66.43 wt% respectively), but miscanthus only produced a yield of 53.46 wt% due to increased feedstock ash content. The ...
Fuel, 2020
Co-pyrolysis is one of the most promising options for using coal and biomass because coal is low ... more Co-pyrolysis is one of the most promising options for using coal and biomass because coal is low in hydrogen and biomass can supplement the hydrogen content to make a more valuable and reactive product gas. The mixture of coal and biomass is prepared, with the mass ratio of biomass varying between 0 and 100 %. Due to limitations in experimental methods, the data points measured in these studies are coarse and therefore, insufficient for kinetic energy analysis and model comparison. Therefore, a mathematical model has been proposed to combine a study of the influence of experimental parameters with different materials to understand better the effect of these parameters on pyrolysis with the rigorous control of experimental conditions in terms of precision and repeatability. The advantages of mathematical modelling co-pyrolysis make it possible to design a reaction scheme capable of describing this phenomenon and extracting kinetic parameters, making it possible to compare fuels, which can be used for the simulation of this process in thermal power plants. The experimental analysis of measured co-pyrolysis data was taken from literature work to validate the proposed model. The numerical model results are in good agreement with the experimental data for co-pyrolysis. The most significant degree of synergetic effects on the product yields was observed at 600℃ and a biomass blending ratio of 70 wt.%. Furthermore, the improvement of char reactivity also identifies the synergies in copyrolysis.
Renewable Energy, 2019
This study presents the first experimental investigation of date palm (Phoenix dactylifera) waste... more This study presents the first experimental investigation of date palm (Phoenix dactylifera) waste fast pyrolysis in a bubbling fluidized bed reactor. The physiochemical characteristics of the feedstock (from cultivars grown in the Emirate of Sharjah in the UAE), including three anatomical parts of the plant, namely, leaves, leaf stems and empty fruit bunches, have been first analyzed and compared to other popular type of biomass. These components have been subjected to fast pyrolysis and mass balances have been derived. The fast pyrolysis products (bio-oil, and non-condensable gas) have been analyzed in terms of their chemical composition, thermogravimetric profiles, and energy content. The overall product distribution in mass percentage at the pyrolysis temperature of 525 ºC was found to be 38.8% bio-oil (including 10.4% reaction water), 37.2% biochar and 24.0% non-condensable gas. The overall energy conversion efficiency (ratio of energy content in the product to that in the feedstock) was found to be 87.0%, thus indicative of the good potential of converting the date palm waste to energy while eliminating the negative environmental impact and cost associated with waste disposal.
Journal of Analytical and Applied Pyrolysis, 2018
Characterisation and Py-GC/MS were conducted to evaluate the bioenergy potential of I. Cylindri... more Characterisation and Py-GC/MS were conducted to evaluate the bioenergy potential of I. Cylindrica. Imperata Cylindrica has a calorific value of 18.39 MJ/kg, with low ash content of 2.97% and high volatile content of 72.01%. Py-GC/MS analysis revealed abundant furanic compounds, guaiacyl lignin, p-hydroxyphenyl lignin, syringyl lignin, aromatic hydrocarbons, ketonic compounds, organic acids and miscellaneous hydrocarbons. Imperata Cylindrica is a potential feedstock for value-added platform chemicals and energy production. The highest bio-oil yield from the pyrolysis of Imperata Cylindrica was 37.16% at 500°C
Fuel Processing Technology, 2018
Bio-oil from the fast pyrolysis of agro-residues still need to contemplate different production s... more Bio-oil from the fast pyrolysis of agro-residues still need to contemplate different production scenarios to look for its feasibility. For this reason, in this work the effect of a range of fast pyrolysis temperature (450, 480, 510 and 550 °C) processing rape straw biomass (with high K content) has been studied in a continuous bubbling fluidised bed reactor. It was found that the catalytic effect of the inorganic content was different at each fast pyrolysis temperature, with the lower temperatures resulting in the highest yield of biooil due to minor catalytic effect (up to 41.39 wt. %). It was also found that at 480 °C the bio-oil presented the best combination of physico-chemical features such as non-separation
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Papers by Tony Bridgwater