Search results for "Torrefaction"
showing 10 items of 12 documents
Influence of Elevated Pressure on the Torrefaction of Wood
2016
The use of pressurized reactors in industrial processes can improve efficiency and economics. Torrefaction is a partial pyrolysis of lignocellulosic biomass designed to result in a solid product with improved fuel properties for utilization in combustion and gasification. In this work, the influence of elevated pressure on the torrefaction of wood has been investigated. Wood samples were torrefied using a pressurized thermogravimetric reactor (PTGR) with pressures of 0.1 to 2.1 MPa. The results indicate that reactor pressure, particle size of feedstock, and wood species are all factors in torrefaction yield improvements. Torrefaction at 2.1 MPa pressure improved the higher heating value (ca…
Biochar from Waste Derived Fuels as Low-Cost Adsorbent for Waste Hydrocarbons
2020
Abstract The aim of this study is to prove technical feasibility of combined refuse derived fuel (RDF) torrefaction and oily wastewater treatment approach by using RDF derived biochar as a sorption media. Biochars prepared from refuse derived fuels in torrefaction, carbonization and pyrolysis modes were analysed as fuels and as hydrocarbon sorbents. Changes of elemental composition and properties of material during thermal treatment and subsequent washing process have been analysed. Experimental evaluation of sorption behaviour of toluene and diesel fuel on obtained biochar performed. Our results show that torrefaction/carbonization of RDF coupled with the subsequent washing of biochar is a…
Torrefied versus conventional pellet production – A comparative study on energy and emission balance based on pilot-plant data and EU sustainability …
2015
Abstract Torrefaction is an emerging technology which enables greater co-firing rates of biomass with coal. To date however there has been a lack of real production data from pilot-scale torrefaction plants. Without such data any environmental benefits of torrefied pellet production are difficult to quantify. In this study data on consumable inputs from a semi-industrial torrefaction plant and the physical properties of produced pellets are used to analyse energy input and air emissions of torrefied pellet production and product transport. EU sustainability criteria are used to compare CO2-equivalent emissions from torrefied and conventional pellet production starting from harvesting of log…
Considerations on factors affecting biochar densification behavior based on a multiparameter model
2021
The optimization of upscaled biochar pelleting is limited by lack of knowledge regarding the effects of process parameters. A multiparameter model, coupled to a single pellet press unit, was for the first time applied to biochar production to predict the upscaled biochar pelleting process behavior. The model permits to estimate in a time and cost-effective way how the die friction forces, quantified through the pellet exiting pressure, are affected by the key process parameters. It was observed that to achieve acceptably low exiting pressures (in the order of 100 MPa), it was critical to produce biochar at high temperatures (e.g. 600 °C). Addition of water as a binder is also beneficial, wh…
A comparative economic analysis of torrefied pellet production based on state-of-the-art pellets
2017
Abstract Torrefied pellets have fuel properties superior to those of conventional wood pellets and potentially allow greater rates of co-firing and thus larger reductions in net CO 2 emissions. Despite the growing amount of scientific output on torrefaction, the economic feasibility of torrefied pellet production is still a topic of considerable uncertainty. This is an obstacle for decision makers looking to implement sustainable energy policies. This paper compares the economics of torrefied pellets to conventional wood pellets. Working backwards from demonstrated pellet properties, this work attempts to answer the following question: Based on state-of-the-art torrefied pellets, what would…
Sorption properties of torrefied wood and charcoal
2014
AbstractPre-treating biomass by torrefaction is assumed to improve the material's storage properties because of reducing hydrophilicity. In order to assess the effect of sorption on storage properties, the adsorption of water vapour and capillary absorption of liquid water in torrefied and charred spruce and birch were studied. In addition, the chemical changes were evaluated through Fourier Transform Infrared (FT-IR) spectroscopy. Adsorption decreased notably as severity of treatment increased, as was expected due to degradation of the wood constituents, namely hemicelluloses and amorphous cellulose. Capillary absorption increased with increasing severity in spruce samples while birch show…
Thermal Decomposition and Combustion of Microwave Pre-Treated Biomass Pellets
2021
The objective of the study was to investigate a more effective use of commercially available biomass pellets (wheat straw, wood, peat) using microwave pretreatment to improve heat production. Pellets were pretreated using the originally designed microwave torrefaction device. The effects of microwave (mw) pretreatment were quantified, providing measurements of the weight loss and elemental composition of pellets and estimating the effect of mw pretreatment on their porosity, surface area and calorific values at pretreatment temperatures of T = 448–553 K. Obtained results show that the highest structural variations and elemental composition during mw pretreatment were obtained for wheat stra…
Torrefaction and pyrolysis of metal-enriched poplars from phytotechnologies: Effect of temperature and biomass chlorine content on metal distribution…
2017
Abstract Torrefaction (290 °C) and pyrolysis (450 and 800 °C) trials were performed at pilot scale with a patented reactor on metal-enriched poplars from a contaminated soil managed by phytotechnologies and poplars cultivated on uncontaminated soil, for comparison. This study emphasized the influence of temperature on end-product yield, metal distribution in end-products and metal behavior. Results showed that the evolution of the end-product yield, i.e. biochar, bio-oil and gas fractions, was depending on temperature rather than other parameters such as the origin or metal content of the tested poplars. Torrefaction decreased the processed poplars weight, leading to metal-enriched torrefie…
Effect of torrefaction on properties of pellets produced from woody biomass
2020
Torrefaction has been recognized as a promising strategy to improve handling and storage properties of wood-based pellets, thus producing a uniform-quality commodity with high energy density and hydrophobicity. In this work, pellets produced from spruce stem wood, bark, and forest residues were torrefied in a bench-scale tubular reactor at 225 and 275 °C with two residence times (30 and 60 min). The effects of torrefaction on general properties, grindability, mechanical properties, hydrophobicity, and microstructure of the studied pellets were investigated. The increase of torrefaction severity reduced mass yields, but the heating values and the fixed carbon content of the torrefied pellets…
Bio-coal, torrefied lignocellulosic resources – Key properties for its use in co-firing with fossil coal – Their status
2012
Abstract Bio-coal has received generous amounts of media attention because it potentially allows greater biomass co-firing rates and net CO2 emission reductions in pulverised-coal power plants. However, little scientific research has been published on the feasibility of full-scale commercial production of bio-coal. Despite this, several companies and research organisations worldwide have been developing patented bio-coal technologies. Are the expectations of bio-coal realistic and are they based on accepted scientific data? This paper examines strictly peer-reviewed scientific publications in order to find an answer. The findings to date on three key properties of torrefied biomass are pres…