[Show abstract][Hide abstract] ABSTRACT: Willow, a leading bioenergy feedstock, may be planted for bioremediation and has been used, more recently, as the biomass feedstock in the manufacture of biochar for agricultural applications. Here, we present a detailed study of the physical and chemical factors affecting willow char properties, where the feedstock is a by-product of bioremediation, potentially transferring pollutants such as heavy metals to the wood feed. Biochar samples were produced via pyrolysis of short-rotation coppice willow, grown on contaminated land, using several treatment times at heat treatment temperatures (HTTs) in the range 350–650 °C, under a constant flow of argon, set at either 100 or 500 mL min−1. The samples were analysed for yield, elemental analysis and structural characteristics, including surface area and pore size distribution, surface functionality and metal content. All chars obtained have high fixed carbon contents but vary in surface characteristics with a marked increase in basic character with increasing HTT, ascribed to the removal of surface oxygen moieties. Results indicate a minimum pyrolysis temperature of 450 °C is required to produce a defined mesoporous structure, as required to facilitate oxygen transport, HTT ≥ 550 °C produces total surface area of >170 m2 g−1 and, more importantly, an appreciable external surface area suitable for microbial colonisation. The data show that selection and optimisation of char properties is possible; however, the interplay of factors may mean some compromise is required.
Full-text · Article · Mar 2014 · BioEnergy Research
[Show abstract][Hide abstract] ABSTRACT: To avoid negative impacts on food production, novel non-food biofuel feedstocks need to be identified and utilised. One option is to utilise marine biomass, notably fast-growing, large marine 'plants' such as the macroalgal kelps. This paper reports on the changing composition of Laminaria digitata throughout it growth cycle as determined by new technologies. The potential of Laminaria sp. as a feedstock for biofuel production and future biorefining possibilities was assessed through proximate and ultimate analysis, initial pyrolysis rates using thermo-gravimetric analysis (TGA), metals content and pyrolysis gas chromatography-mass spectrometry. Samples harvested in March contained the lowest proportion of carbohydrate and the highest ash and alkali metal content, whereas samples harvested in July contained the highest proportions of carbohydrate, lowest alkali metals and ash content. July was therefore considered the most suitable month for harvesting kelp biomass for thermochemical conversion to biofuels.
Full-text · Article · Jan 2011 · Bioresource Technology
[Show abstract][Hide abstract] ABSTRACT: Biochar is a black, carbon-rich, material produced by thermally treating biomass materials in zero- or limited- oxygen conditions using a process called pyrolysis. When applied to land, biochar is not only a carbon sink, but can act as a soil improver by increasing the water and nutrient- holding capacity of the soil. It may also be effective in reducing greenhouse gas emissions from the soil. With the correct calibration, therefore, biochar application could offer considerable benefits in terms of mitigating climate change, improving food security and reducing reliance on chemical fertilisers, all of which could have considerable environmental and economic advantage.
[Show abstract][Hide abstract] ABSTRACT: 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.
Full-text · Article · Oct 2010 · Bioresource Technology
[Show abstract][Hide abstract] ABSTRACT: Fifteen Miscanthus genotypes grown in five locations across Europe were analysed to investigate the influence of genetic and environmental factors on cell wall composition. Chemometric techniques combining near infrared reflectance spectroscopy (NIRS) and conventional chemical analyses were used to construct calibration models for determination of acid detergent lignin (ADL), acid detergent fibre (ADF), and neutral detergent fibre (NDF) from sample spectra. Results generated were subsequently converted to lignin, cellulose and hemicellulose content and used to assess the genetic and environmental variation in cell wall composition of Miscanthus and to identify genotypes which display quality traits suitable for exploitation in a range of energy conversion systems. The NIRS calibration models developed were found to predict concentrations with a good degree of accuracy based on the coefficient of determination (R2), standard error of calibration (SEC), and standard error of cross-validation (SECV) values. Across all sites mean lignin, cellulose and hemicellulose values in the winter harvest ranged from 76–115 g kg−1, 412–529 g kg−1, and 235–338 g kg−1 respectively. Overall, of the 15 genotypes Miscanthus x giganteus and Miscanthus sacchariflorus contained higher lignin and cellulose concentrations in the winter harvest. The degree of observed genotypic variation in cell wall composition indicates good potential for plant breeding and matching feedstocks to be optimised to different energy conversion processes.
No preview · Article · May 2010 · Biomass and Bioenergy
[Show abstract][Hide abstract] ABSTRACT: The objectives of the experiment were to assess the impact of nitrogen (N) and potassium (K) fertiliser application on the cell wall composition and fast-pyrolysis conversion quality of the commercially cultivated hybrid Miscanthus x giganteus. Five different fertiliser treatments were applied to mature Miscanthus plants which were sampled at five intervals over a growing season. The different fertiliser treatments produced significant variation in concentrations of cell wall components and ash within the biomass and affected the composition and quality of the resulting fast-pyrolysis liquids. The results indicated that application of high rates of N fertiliser had a negative effect on feedstock quality for this conversion pathway: reducing the proportion of cell wall components and increasing accumulation of ash in the harvested biomass. No exclusive effect of potassium fertiliser was observed. The low-N fertiliser treatment produced high quality, low ash-high lignin biomass most suitable as a feedstock for thermo-chemical conversion.
Full-text · Article · Mar 2010 · Bioresource Technology
[Show abstract][Hide abstract] ABSTRACT: Biomass from forage and energy crops can provide a renewable source of meat, milk, and wool, or power, heat, transport fuels
and platform chemicals, respectively. Whilst in forage grasses some improvements have been made, the potential of energy grasses
is limited because plant varieties have not yet been selected for this purpose. There are distinct challenges to determine
and improve quality traits which increase ultimate energy yield but experience from forage crops can help. Energy grasses
offer the potential to be utilised through either thermal or biological conversion methods with the route chosen being largely
determined by the calorific value, moisture content and the ratio of soluble to structural carbohydrates. Plant chemical composition
underlies these characteristics, for example whichever way grass feedstocks are converted the major determinates of energy
are lignin, cell wall phenolics and the soluble and cell wall carbohydrates. These components affect the efficiency of the
energy conversion process to meat, milk, wool, energy, platform chemicals and the end quality of certain liquid fuels such
as pyrolysis oils. To associate phenotype to genotype for such underlying chemical composition, it is necessary to develop
both DNA based molecular markers and high throughput methods for compositional analysis. The genetic resources available in
forage and energy grasses are limited in comparison with several model grasses including maize and for some traits it may
be appropriate to work initially on such a model and then translate this research back to the forage or bioenergy crop. However
not all traits will be present in the model, and so genetic and genomic resources are and will have to be developed in the
crops themselves. As part of the EU project GRASP, SNP based markers have been developed in carbohydrate associated genes
which map to soluble carbohydrate QTL in Lolium perenne (perennial ryegrass) and these have been used in association studies in a synthetic population of L. perenne to measure allele shifts. High throughput calibration models have been developed using near infrared reflectance spectroscopy
(NIRS) and Fourier transform infrared spectroscopy (FTIR) in the mid-infrared spectral range which allow accurate predictions
of a number of composition traits including lignin, cellulose and hemicellulose contents in several forage and energy grasses
including Miscanthus, L. perenne and related species. These calibrations have allowed a comparison of chemical composition from different grass genotypes,
species and environments. Both tools and genetic resources for the optimisation of biomass as forage and energy feedstocks
are therefore being developed to enable association of phenotype with genotype.
[Show abstract][Hide abstract] ABSTRACT: Two energy grass species, switch grass, a North American tuft grass, and reed canary grass, a European native, are likely to be important sources of biomass in Western Europe for the production of biorenewable energy. Matching chemical composition to conversion efficiency is a primary goal for improvement programmes and for determining the quality of biomass feed-stocks prior to use and there is a need for methods which allow cost effective characterisation of chemical composition at high rates of sample through-put. In this paper we demonstrate that nitrogen content and alkali index, parameters greatly influencing thermal conversion efficiency, can be accurately predicted in dried samples of these species grown under a range of agronomic conditions by partial least square regression of Fourier transform infrared spectra (R(2) values for plots of predicted vs. measured values of 0.938 and 0.937, respectively). We also discuss the prediction of carbon and ash content in these samples and the application of infrared based predictive methods for the breeding improvement of energy grasses.
[Show abstract][Hide abstract] ABSTRACT: Proceedings of the 5th International Symposium on the Molecular Breeding of Forage and Turf 2007 (MBFT 2007), Sapporo Convention Center, Japan, 2-6 July 2007. This book includes papers from plenary lectures and selected oral presentations of the 5th International Symposium on the Molecular Breeding of Forage and Turf. A wide variety of themes are addressed in a collection that provides authoritative reports on the recent progress and understanding of molecular technologies and their application in plant breeding. The book covers almost all relevant areas in molecular breeding of forage and turf as well as biofuel crops, from gene discovery to the development of improved cultivars.