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Wildfires are getting extreme and more frequent because of increased fuel loads in the forest and extended dry conditions. Prevention of wildfire by fuel treatment methods will generate forest residues in large volumes, which in addition to available logging residues, can be used to produce biofuels and bioproducts. In this study, the techno-economic assessment of three portable systems to produce woodchips briquettes (WCB), torrefied-woodchips briquettes (TWCB) and biochar from forest residues were evaluated using pilot-scale experimental data. A discounted cash flow rate of return method was used to estimate minimum selling prices (MSPs) for each product, to conduct sensitivity analyses, and to identify potential cost-reduction strategies. Using a before-finance-and-tax 16.5% nominal required return on investment, and a mean transport distance of 200 km, the estimated delivered MSPs per oven-dry metric ton (ODMT) of WCB, TWCB, and biochar were $162, $274, and $1044 respectively. The capital investment (16–30%), labor cost (23–28%), and feedstock cost (10–13%) without stumpage cost were the major factors influencing the MSP of solid biofuels and biochar. However, the MSPs of WCB, TWCB, and biochar could be reduced to $65, $145, and $470/ODMT respectively with technologically improved portable systems. In addition, the MSPs of solid biofuels and biochar could be further reduced by renewable energy and carbon credits, if the greenhouse gas (GHG) reduction potentials are quantified and remunerated. In conclusion, portable systems could be economically feasible to use forest residues and make useful products at current market prices while simultaneously reducing potential wildfires and GHG emissions.

As urbanization continues, water pollution is of increasing concern for human health and the environment. Water contaminants common in urban stormwater include nutrients, metals, suspended solids, pesticides, and pathogens. The search for an inexpensive and readily available material that can effectively remove common stormwater contaminants is ongoing. Studies have shown that woodchips are a promising material that can remove many different contaminants, including these common contaminants and emerging contaminants of concern. The type of wood and shape of woodchips can impact the removal efficiencies of different contaminants due to different partitioning coefficients and capillary action. This review compiles studies on the ability of woodchips of different types to remove these common stormwater contaminants and emerging contaminants of concern. Overall, the literature demonstrated woodchips are an inexpensive and effective material that could be implemented for the removal of contaminants in urban stormwater.

The paper concerns the analysis of harmful emissions during the combustion process in households. The subject of the analysis is a low emission heating device with an output of 50 kW for burning biomass of forest origin (low-quality hardwoods or softwoods). The proposed boiler is automatically fed from the connected container by means of a screw conveyor. In this way, the optimum amount of fuel is supplied for maximum heat output (adjustment of the ratio of primary air to fuel). The proposed biomass heating system is equipped with a primary and secondary air supply system and exhaust gas sensors. This ensures optimal regulation of the air mixture and efficient and clean combustion. Proper control of the combustion process, control of the air supply by means of a lambda sensor and power control of the system ensure a low-emission combustion process. The system precisely adjusts to the heat demand. This results in highly efficient heating technology with low operating costs. In the presented work, the emission of exhaust gases from the proposed heating device during the combustion of woodchips and beech–oak pellets were measured. It is demonstrated that the proposed design of the boiler equipped with intelligent control significantly reduces emissions when the biomass solid fuels are used, e.g., CO emissions from beech and oak chips and pellets in the low-emission boiler—18 extract pipes shows the value

Future research will be focused on understanding the effect of gasification conditions on biochar properties, and correlating biochar properties with soil application related greenhouse gas emissions and soil properties, as well as crop performance. Chicken manure and rice hull biochar were pre-mixed and co-composted to produce an organic fertilizer. Simultaneous production of biochar and combustible syngas was achieved with top-lit updraft gasification of rice hulls and woodchips. Biomass gasification is considered one of the most promising technologies for production of high-quality biofuels. Biomass gasification has many advantages over direct combustion. It converts low-value feedstocks to high-quality combustible gases, which can be not only directly burned or used for heat or electricity generation but also turned into liquid transportation fuels, such as Fischer-Tropsch (FT) diesel and gasoline. The FT process produces high-value, colorless, odorless, and low-toxicity clean-burning fuels that can be used in conventional engines with little or no modification.

Storage is the critical operation within the biomass supply chain to reduce feedstock supply risks and to manage smooth year-around operations of a biorefinery or a bioenergy plant. This paper analyzed the economic and environmental impacts of four different biomass storage systems for woodchips (Outdoor-open, Outdoor-tarped, Indoor, and Silo) and two systems for pellets (Indoor and Silo). Storage cost includes the costs for handling (including ventilation in case of silo storage), infrastructure investment, and dry matter loss (DML) for each system. The estimation of total greenhouse gas (GHG) emissions includes the fugitive emissions from storage piles and emissions due to electricity and fuel consumption for each system. Among four storage systems, the outdoor-tarped ($15.0 ODMT−1, ODMT: Oven Dry Metric Ton) and silo ($5.8 ODMT−1) storage were the least-cost options for woodchips and pellets respectively. However, silo-storage could be the most promising option for storing woodchips ($5.8 ODMT−1) and pellets ($2.3 ODMT−1), if it is used for short-term (two months) and frequently (at least six times) in a year. The total GHG emissions for six-month storage were 2.8–11.8 kgCO2e ODMT−1 for woodchips and 8.6–42.0 kgCO2e ODMT−1 for pellets. During Outdoor-open storage, the lower heating value of woodchips could drop to 37% due to increased dry-matter loss (DML) and moisture content. The initial moisture content, bulk density, DML, and resource required during handling were the most sensitive parameters influenced the storage performances of both woodchips and pellets. This study has demonstrated that a combination of different storage options along the supply chain could reduce the total biomass storage cost for a biorefinery or power plant.

The use of woodchips of local origin for heating purposes is a diffused practice in some areas, like northern Italian alpine and sub-alpine zones, where large woods and forests extensions occur. In recent years, many thermal plants producing energy using woodchips as fuel have been constructed, supplying single edifices and delivering heated water to small communities through district heating. Unfortunately, due to the Chernobyl fall-out, particularly relevant in many mountain areas of northern Italy, woodchips of local origin are often contaminated with relevant 137Cs traces: therefore, the woodchips burning aimed at water heating produces ashes in which the 137Cs activity concentration is highly enriched with respect to that of the raw material. Typical activity concentrations of 137Cs in such ashes span a range from a few hundreds to several thousands Bq/kg. These combustion ashes are subject to different fates, according to reuse opportunities and law restrictions (not referred to the radiological aspects). Landfill disposal is the most common general option, together with the use in compost production plants and concrete factories. In this paper, we focused in particular to the use of concrete containing highly contaminated ashes, being considered as the most relevant from the radioprotection point of view. Therefore, some evaluations of the public exposure to radiations coming from concrete utilized as building material and containing woodchip ashes with high radioactivity levels (specifically 137Cs and 40K) have been done. The dose estimates for a person living in a house built with “contaminated” concrete were made using both standardized gamma radiation exposure indices and simulation models. The results are presented and discussed. Finally, a new formulation of the activity concentration index I is proposed for a safe and radioprotection sound use of building material containing woodchip ashes.

In this study, we developed a techno-economic model to estimate the production cost of renewable diesel and gasoline from aspen woodchips through fast pyrolysis-based bio-oil and its subsequent hydroprocessing. The whole pathway includes the conversion of woodchip biomass to bio-oil through fast pyrolysis followed by upgrading to transportation fuels via hydroprocessing. Experiments were carried out to develop for the process model. This detailed process and techno-economic study was done based on 2000 dry t day−1 aspen woodchips (base case capacity), from which we estimated the cost to produce renewable diesel and gasoline. For this base case, using the present method, 148.81 ML year−1 of renewable diesel and 99.21 ML year−1 of gasoline using merchant hydrogen can be produced. The production costs of renewable diesel and gasoline for 2000 t day−1 are 1.09 and 1.04$ L−1, respectively. We also studied the effect of changing the scale of the facility from 500 to 5000 t day−1 on the production costs of renewable diesel and gasoline. The economic optimum plant size (the capacity at which fuel production cost is lowest) was determined to be 3000 t day−1. Finally, we carried out sensitivity and uncertainty analyses for the base case and determined that production cost is most sensitive to bio-oil yield and internal rate of return (IRR).

To realize full energy recovery from grass and chicken manure (CM), the integration of high-solid anaerobic digestion (HSAD) and gasification was investigated experimentally. The anaerobic biodegradability of grass can be enhanced through codigestion with CM. When the volatile solids (VS) ratio of CM to grass was 20:80, C/N ratio calculated to be 21.70, the cumulative biogas yield was the highest, 237 ml·g − 1 VS. The enhancement of biogas production was attributed to the buffering effects of ammonia and rich trace elements in CM. In semi-continuous systems, when the organic loading rate was 4.0 g VS·L − 1 ·d − 1 , the HSAD process was stable, with the average biogas yield 168 ml·g − 1 VS. More than 80% fractions of the digestates were volatile matters, which meant that the digestates can be used as feedstock for gasification to produce syngas. The VS ratio of grass to CM had significant overall energy generation through HSAD and gasification. Compared with gasification of digestate, cogasification with woodchips increased syngas yield and low heat value (LHV). Increasing of mass ratio of digestates to woodchips led to the decrease of LHV.

The characteristics and applications of carbonaceous materials play a vital role in silicon production using an electric arc furnace, as this is an energy-intensive industry with high energy operating costs that is currently facing severe challenges to become more sustainable and more competitive. In this study, the effect of different carbon materials on specific electrical consumption and the exergetic efficiency and the silicon yield for two types of furnace was investigated using a statistical analysis method based on actual production data from the silicon plant. The highest exergetic efficiency values of 0.39 (8.3 MVA) and 0.42 (12.5 MVA) without recovery were obtained by the application of petcoke and charcoal. The exergetic efficiency was higher in the larger capacity furnace than in the smaller furnace for the same consumption of raw materials. The correlation between exergetic efficiency and carbon materials was evaluated and revealed that the moisture content and graphitization of raw materials have a significant effect on the exergetic efficiency. The reactivity of mixtures was improved by synergistic interactions between petcoke and coal or woodchips, which increased the carbothermic reduction utilization of silica based on the higher silicon yield indicator, but reduced the exergetic efficiency and silicon actual production, as it increased the specific electrical consumption.

There is a growing demand for alternative forms of energy that could firstly replace fossil fuels, with the environmental advantages resulting therefrom, but that could be as well economically more beneficial by allowing companies to obtain competitive advantages from the aforementioned alternative forms of energy. In this sense, the use of waste to produce thermal energy is presented as an alternative worthy of study. In this paper, an analysis is made of the use of waste from the textile industry, more precisely cotton waste, which is used as a renewable resource for the production of thermal energy. After the characterization of the waste, the energetic potential is determined comparatively to other fuels such as woodchips and wood pellets. A comparative economic assessment with other fuels is carried out. The obtained results show that the cotton briquettes have a heating value of 16.80 MJ/kg and a cost of 0.006 €/kWh when used as fuel. This predicts an annual reduction in fuel cost of 80, 75 and 70% when compared with fuel-oil, wood pellets and wood chips, respectively. Thus, the use of cotton waste could be a viable alternative, economically and environmentally, to produce thermal energy.

In Chile, the demand for pellets has increased considerably in the last years. However, woodchips and sawdust from Pinus radiata which are the traditional materials used for its confection are not always available, making it necessary to investigate other biomass sources complementary. In this study, the residue from corn milling (corn dust) in a maximum distance of 49 km from the pellet production company was analyzed and evaluated as a biomass source. The physical-mechanical and energetic properties of this material were analyzed, then the quality of the pellets created with different percentages of this and P. radiata sawdust was determined. The company requires 10,000 tons of material for its production at a cost of US$80,000 annually. Its distance from the sources of P. radiata sawdust causes it to make them pay US$ 8 t −1 for the material compared to US$ 3 t −1 that companies close to the sources pay, affecting its competitiveness. It was determined that the test tube 50M/50PR meets all the quantitative, qualitative and economic requirements. The acquisition of the 5000 tons required would generate a cost of US$5800 in transporting this material to the plant, this way the company would save US$34,200 in its operational costs annually.

The life cycle energy consumption and greenhouse gas (GHG) emission performances of forest biomass-derived oxymethylene ether (OME) synthesis used as a diesel additive are analyzed in this study. OME, a new alternative liquid fuel, has great miscibility with conventional fuels like diesel. OME can reduce combustion emissions significantly when used as a diesel additive without any modification to the engine. A data-intensive spreadsheet-based life cycle assessment (LCA) model was developed for OME synthesis from woodchips derived from two different kinds of forest biomass, whole tree and forest residue. Woodchip harvesting, chip transportation, chemical synthesis of OME from biomass-derived syngas, OME transportation to blending, and vehicle combustion of this transportation fuel were considered in the system boundary. The results show that the whole tree pathway produces 27 g CO2eq/MJ of OME, whereas the forest residue pathway produces 18 g CO2eq/MJ of OME over 20 years of plant life. The difference is mainly due to some emissions-intensive operations involved in biomass harvesting and biomass transportation such as skidding, road construction, etc., in the whole tree pathway. Also, vehicle combustion was found to be the most GHG-intensive unit for both pathways. OME combustion in a vehicle accounts for about 77% and 83% of the total life cycle GHG emissions for the whole tree and forest residue pathways, respectively. This study also compares the diesel life cycle emission numbers with the life cycle emissions of OME derived from forest biomass, and it was observed that GHG emissions can be reduced by 20–21% and soot (black carbon) emissions can be reduced by 30% using a 10% OME blended diesel as a transportation fuel compared with conventional diesel.

The silicon industry is an energy-intensive industry with high energy operating costs and is currently facing new challenges to improve sustainability and become more competitive. Petroleum coke, coal, and charcoal are typically utilized as carbonaceous reductants for silicon production, and the mixture of different carbonaceous materials plays a very important role in the specific power consumption and the exergy efficiency of the process. Of these materials, in particular, charcoal preparation requires large amounts of wood, and continued and extensive deforestation contributes to ecological damage. Thus, it is urgent to study carbonaceous reductants that can be alternatives to charcoal or to find strategies that do not require the application of charcoal in the silicon production process. Exergy efficiency was used as an overall indicator to evaluate the effect of different carbon materials on the process of silicon production in this study. An exergetic efficiency of 0.39 was obtained for silicon produced with a mixture of woodchips and no charcoal. The overall exergy efficiency and the silicon yield exergy indicator results indicated that the addition of woodchips to a mixture of carbonaceous materials improved the performance of the silicon furnace, even if the fixed carbon contribution was lower. There was no change in exergetic efficiency (0.33) for the mixture of petroleum coke and coal as carbonaceous materials with or without charcoal and woodchips. Therefore, a mixture of petroleum coke and coal without charcoal can be used as carbonaceous reductants while maintaining the exergetic efficiency of the process of silicon production.

Forestry thinning logs, a low-value by-product of the forestry industry, present an opportunity for bioenergy production. It can be converted into solid, liquid, and gaseous fuels via different conversion techniques. Comparative life cycle assessment and life cycle costing (LCC) analysis were conducted to evaluate six options: woodchip gasification for power generation; wood pellets gasification in combined heat and power plant; wood pellet combustion for domestic water and space heating; pyrolysis for power generation; pyrolysis with bio-oil upgrading to transportation fuels; and ethanol production for transportation fuel mix. The functional unit used in this study was the treatment of 1 Mg of biomass. Global warming; acidification; eutrophication; fossil depletion, human toxicity; and land use impact categories were considered. The LCC also included greenhouse gas (GHG) emissions costs. The effects of uncertainties in the system on the overall performance of the scenarios were also evaluated. The results showed that all options except for ethanol production are GHG emission negative. Woodchips gasification performed best in all environmental impact categories and had the lowest LCC ($177.6/Mg). Biomass drying consumed more than 50% of the energy requirement for all options except for production of liquid transportation fuels via upgrading of pyrolytic oil, in which case the fuel upgrading process was the most energy intensive. In terms of energy return, all options, except electricity production through pyrolysis, offered positive return. The results highlight the importance of using biomass with least possible processing in order to maximise environmental and energy return and minimise LCC.

The objective of this study is to perform a comparative estimation of the life cycle environmental performance of biochar from woodchip pyrolysis, and woodchip combined heat and power production. The wood processing industry draws up over 14% of the whole industrial sector turnover, making the wood industry one of the most valuable players in the Latvian economy. Woodchips are valuable logging residues integrated in the energy sector. The environmental performance is analyzed through the Life Cycle Assessment (LCA). LCA is performed according to the methodology described in the ISO 14040:2006 standards using the SimaPro 8.1.0.60 software and the Ecoinvent 3.1. database.

Woodchip is widely used as fuel in dedicated biomass and, even in some conventional energy generation plants. However, there are concerns about atmospheric air pollution from flue gases emitted during wood biomass combustion, particularly oxides of nitrogen (NOx) and particulates

The environmental legislation and strict enforcement of environmental regulations are the tools effectively used for developing the market of materials for environmental protection technologies. Sustain ability criteria shift environmental engineering systems to more sustainable-material-based technologies. For carbon-based medium materials in biofiltration, this trend results in attempts to use biochar for biofiltration purposes. The paper presents the analysis of biochar properties based on the main criteria for biofiltration medium integrating the environmental quality properties of biochar, following the European Biochar Certificate guidelines. Three types of biochar produced from feedstock of highly popular and abundant types of waste are analysed. A multi component approach was applied to summarize the results. The lignocellulosic type of biochar was found to be more competitive for use as a biofiltration medium than the types of biochar with high ash or lignin content. (C) 2016 Elsevier Ltd. All rights reserved.

The possibility of using construction and demolition (C&D) waste wood as a bulking material in biosolids composting was investigated. Potential contaminants in C&D waste wood include arsenic (As), chromium (Cr), and copper (Cu) from treated wood, and lead (Pb) from paints. Untreated and treated woodchips from C&D wood were mixed with biosolids, composted using an aerated static pile process, and cured. There were no significant differences between untreated and treated woodchips with respect to composting process, time to stability, or product quality. Composting parameters monitored included moisture content, pH, electrical conductivity, organic matter degradation, fecal coliform levels, and stability by respirometry. Finished compost quality was evaluated in terms of potential toxic elements (PTE) levels. PTE values in treated woodchips (26 ± 35, 29 ± 41, 56 ± 46, and 5 ± 5 µg·g−1 for As, Cr, Cu, and Pb, respectively) were higher and more variable than those in the untreated woodchips (3 ± 3, 17...

The valorization of residual biomass plays today a decisive role in the concept of &ldquo, circular economy&rdquo, according to which each waste material must be reused to its maximum extent. The collection and energy valorization at the local level of biomass from forest management practices and wildfire prevention cutting can be settled in protected areas to contribute to local decarbonization, by removing power generation from fossil fuels. Despite the evident advantages of bioenergy systems, several problems still hinder their diffusion, such as the need to assure their reliability by extending the operating range with materials of different origin. The Italian project &ldquo, INNOVARE&mdash, Innovative plants for distributed poly-generation by residual biomass&rdquo, funded by the Italian Ministry of Economic Development (MISE), has the main scope of improving micro-cogeneration technologies fueled by biomass. A micro-combined heat and power (mCHP) unit was chosen as a case study to discuss pros and cons of biomass-powered cogeneration within a national park, especially due to its flexibility of use. The availability of local biomasses (woodchips, olive milling residuals) was established by studying the agro-industrial production and by identifying forest areas to be properly managed through an approach using a satellite location system based on the microwave technology. A detailed synergic numerical and experimental characterization of the selected cogeneration system was performed in order to identify its main inefficiencies. Improvements of its operation were optimized by acting on the engine control strategy and by also adding a post-treatment system on the engine exhaust gas line. Overall, the electrical output was increased by up to 6% using the correct spark timing, and pollutant emissions were reduced well below the limits allowed by legislation by working with a lean mixture and by adopting an oxidizing catalyst. Finally, the global efficiency of the system increased from 45.8% to 63.2%. The right blending of different biomasses led to an important improvement of the reliability of the entire plant despite using an agrifood residual, such as olive pomace. It was demonstrated that the use of this biomass is feasible if its maximum mass percentage in a wood matrix mixture does not exceed 25%. The project was concluded with a real operation demonstration within a national park in Southern Italy by replacing a diesel genset with the analyzed and improved biomass-powered plant and by proving a decisive improvement of air quality in the real environment during exercise.

Apart from being used as an oil stock for bio-fuels production, an annual crop plant Brassica napus, thought to be an agro-waste, and used either as an animal feed, soil fertilizer or biomass for combustion and thermal energy production. Alternatively, as a bio-based and locally bio-sourced cellulosic material, it could be used as a thermal insulation in sustainable building fabrication, likewise woodchips, a bio-waste from the wood industry. In this study, the above-mentioned bio-waste materials&rsquo, thermal properties were identified using a sandwich panel from medium density fibreboard (MDF) and wood studs. Premanufactured panels have been filled in with randomly oriented short-cut rapeseed and with short-cut woodchips. A modified guarded hot box method was used to designate steady and un-steady state thermo-physical parameters of such insulation panels. The examined bio-waste materials absorbed thermal fluctuations of the exterior environment and kept the indoor building environment at constant temperature regardless of such fluctuations. The ability of bio-based sandwich panels to store heat energy was found to be similar to mineral wool. Additionally, VOC (volatile organic compound) emissions of tested materials were identified using gas chromatography-mass spectrometry (GC-MS) combined with headspace solid-phase microextraction (HS-SPME) to declare materials&rsquo, harmlessness to indoor environmental quality and human wellbeing. In conclusion, bio-based short-cut materials proved to be a viable environmentally friendly and energy efficient alternative to conventionally used thermal insulations.

An alternative way has been proposed for the PVC-containing medical wastes valorization by co-hydrothermal carbonization (HTC) with lignocellulosic biomass. The organic-Cl in PVC can be converted to the inorganic-Cl via hydrolysis, defunctionalization, recondensation, and aromatization in the HTC process. Followed by the washing process with the condensed water, the inorganic-Cl with high water-solubility could be removed from the solid products (i.e. hydrochar). Lignin as a biomass component can significantly improve the dechlorination efficiency of PVC in the HTC process. Here, the dechlorination performance of lignocellulosic components is given as the following order: lignin > cellulose > hemicellulose. In addition, lignin can adjust the particle sizes of solid products by inhibiting the agglomeration in the order of lignin > hemicellulose > cellulose. In the pilot-scale HTC process, the addition of woodchips improves the dechlorination efficiency of hospital wastes (HW). The hydrochar particles with low-chlorine content and higher heating value could be used as a clean coal-alternative fuel.

Gasified biomass syngas has been successfully used to produce liquid hydrocarbons at pilot scale using a novel biochar-supported catalyst. Producer gas from a downdraft gasifier was made from woodchips and contained 53% N2, 17% CO, 14% H2, 13% CO2, and 2% CH4 after undergoing a rigorous scrubbing and refining process. The producer gas was successfully scrubbed so that the catalyst contaminants contained in the gas (e.g., NH4 and O2) were lower than 1 ppm. This study involved over 2000 h of biomass syngas trials at the pilot plant and achieved objectives to better understand and overcome challenges associated with reactor scale-up. A mass balance closure of ±5% was achieved. Producer gas, which flowed through the system only once (without a recycle loop), had a CO conversion of 59% or greater after being introduced to the novel biochar-supported catalyst. The pilot-scale catalyst bed had a much greater surface area for the gas to flow through than previously tested lab-scale reactors (approximately 15 times more surface area), which allowed channels to form and flow regimes to be more inconsistent than in the smaller reactor tubes. This accounted for the lower yield, so smaller tubes are suggested to improve efficiency and overall yield.

In countries like Latvia, with large forest areas and intensive forestry, large quantities of forest residues are formed. The primary use of forest residues is processing it into forest woodchip fuels. However, it is generally thought that forest woodchips are of poor quality, with one of the main weak spots being low ash melting temperature that accounts for the creation of molten ash in boilers. Molten ash formation in boiler furnaces significantly increases equipment maintenance costs. Thus, this resource is not used to its full potential. The ash melting temperature varies for different materials. The different ash melting properties of different logging residue fuel parts is investigated, highlighting the fractions which contribute to the formation of molten ash in the largest extent. Ash melting properties are evaluated separately for pine and spruce branches and needles. The ash melting properties are evaluated in a mutual relationship as well as in the context of previous research.

Biomass gasification with CO2 as the gasifying agent is a promising way to relieve the energy shortage and minimize CO2 emission. In this study, Eulerian method was used to study the CO2 gasification of biomass in a fluidized bed gasifier. It was found that the CO2 percentage in the gasifying mixture with air, the CO2-to-biomass ratio, the moisture content of woodchips, and the woodchip size had great influence on the gasification performance. With the increasing CO2-to-biomass ratio, the mole fraction of CO in the producer gases would be increased while those of H2 and CO2 vary in the opposite trend. When CO2 mass percentage in the gasifying agent was 60%, the fractions of CO and CH4 in the producer gas reached the maximum, as well as the lower heating value and cold gas efficiency, so this was the optimal condition when the gasifier had the best performance. The moisture content and particle size of the woodchips had negative effects on the gasification performance, because of the lower heating value of producer gases, cold gas efficiency and CO2 conversion ratio were both reduced with increasing moisture content and particle size. This study offers a promising way to integrate the gasification of renewable biomass with CO2 capture, and may be helpful in the design and operation of biomass gasifier.

Substrate characterization experiments were carried out on different feedstocks and structure materials considered appropriate for use in dry anaerobic batch digestion systems. Physical material characteristics tested were bulk and saturated bulk density, compressed density, permeability, compactibility, water holding capacity, maximum water content, and volatile solid content. Oedometer tests were conducted on prepared feedstock/structure material mixtures targeting a high permeability under compression. Porous materials such as straw and woodchips were tested to determine if they enhance material mixture properties to yield superior permeability and allow percolation.

In 2014, the European standards of solid biofuel classification have been replaced by the International ISO standards. Considering wood chips, the main change concerns the definition of particle size distribution classes. This change in the quality, as a consequence of the new standard rules, has been quantified using 206 wood chips samples. The results show an improved classification of particle size distribution of woodchips with a reduction of not classified samples from 40 to 14% and an increase in samples belonging to the dimensionally smaller particle size classes.

European Union has set a 70 % recycling goal for construction and demolition waste by 2020. In Finland, for example, 40 % of this waste is wood. The purpose of this study was to test the technical feasibility of pulping contaminated wood waste from the construction industry and using such pulps for fibre-based products outside of the conventional paper industry. It was found out that both chemical and thermo-mechanical pulping, and mechanical milling can be used for pulping contaminated wood waste chips received from construction waste treatment plant. The resulting pulps were then utilized successfully to prepare product demonstrations (wood fibre filaments and thick foam formed panel structures). There are no technical restraints for pulping contaminated construction wood waste, and the resulting pulp quality depends on the shape and size of the woodchips, dry content, wood species and type of contaminants. Although wood treated with copper preservatives can set special safety and process requirements, it does not necessarily impair the key properties of the final product.

Co-processing of woody biomass with two bio-chars (bio-chars made from switchgrass and red oak bark) was studied as a way of upgrading the pyrolysis vapors. The clean woodchips were pyrolyzed with and without bio-chars under atmospheric pressure at the target temperature of 500 °C. The co-processing with both bio-chars showed a significant influence on the bio-oil yields, moisture content and pH value of bio-oils. However, the vapor-upgrading process significantly decreased the carbon yield in the bio-oil when using switchgrass bio-char was used for co-processing. The bio-oil yield decreased from 49.31% (non-bio-char) to 44.81% with the switchgrass bio-char and to 48.68% with the bio-char from the red oak bark. The lost mass of bio-oil ended-up in the gaseous phase as reflected in an increased content of carbon dioxide and carbon monoxide. The gaseous-phase composition of hydrogen increased from 0.82% to 3.74%, of carbon dioxide from 21.16% to 32.33%, and of carbon monoxide from 16.49% to 23.19% with the addition of the switchgrass bio-char compared to non-bio-char pyrolysis.

This study analyses the impact on the GHG (greenhouse gas) emissions of the raw material supply chain, the utilisation of excess heat and CO2 storage for a bio-SNG (biomass gasification-based synthetic natural gas) system by applying a consequential life cycle assessment approach. The impact of the biomass supply chain is analysed by assessing GHG emissions of locally produced woodchips and pellets with regional or transatlantic origin. Results show that the supply area for the gasification plant can be substantially increased with only modest increases in overall GHG emissions (3-5%) by using regionally produced pellets. The transatlantic pellet chains contribute to significantly higher GHG emissions. Utilising excess heat for power generation or steam delivery for industrial use contributes to lower emissions from the system, whereas delivery of district heating can contribute to either increased or decreased emissions. The production technology of the replaced heat and the carbon intensity of the reference power production were decisive for the benefits of the heat deliveries. Finally, the storage of CO2 separated from the syngas upgrading and from the flue gases of the gasifier can nearly double the GHG emission reduction potential of the bio-SNG system. (C) 2015 Elsevier Ltd. All rights reserved.

This paper is aimed to assess the performance of air blown fixed-bed downdraft gasification of local lignocellulosic biomasses which in perspective of Southern Norway are both available and sustainable. Long rotation forest crops birch, oak and spruce, coupled with energy crops poplar and willow were used as feedstocks. The gasification conditions undertaken were widely varied in-terms of air (∼3.20–4.20 N m3/h) and fuel flow (∼1.70–2.10 kg/h) so that the corresponding equivalence ratio (ER) differed (0.19–0.80) and ultimately reflected to other operational parameters such as bed temperature (∼550–760 °C maximum), producer gas yield (∼1.50–2.30 N m3/kg, wet base), cold gas efficiency (∼35–51%), carbon conversion efficiency (∼61–76%) and so on. An emphasis was also placed on evaluating material balance by accounting the by-products (such as tar, char) of gasification so that the system reliability is identified. Overall, the gasification performance of different woody biomass was found viable over a broad range of operating condition which is appealing in contributing this technology in the context of regional bioenergy and thus towards the renewable energy.

This paper describes the research done in order to valorise the biomass ash and evaluate its use as supplementary cementitious material (SCM) in the cement industry. The biomass ash samples used in this study were collected from three different power plants. The characterisation of the ashes as SCMs was performed after two different valorisation processes: (i) a vitrification process in order to obtain a new material with high hydraulicity and (ii) an easy de-alkalisation process in order to reduce the alkali content. The results of this work show that biomass ash derived from the combustion of woodchips and straw, properly treated, is characterised by pozzolanic activity and latent hydraulicity that could be exploited for the manufacture of low embodied energy concrete. The ultimate strength of mortars prepared using vitrified biomass ash becomes higher than that of the parent Portland cement after 28 days.

Hot water extraction of aspen woodchips was treated at about 160 °C for 2 h with a liquor-to-solid ratio of 4.76:1 in a 1.84 m3 batch reactor with external liquor circulation. Both five-carbon and six-carbon sugars are obtained in the extraction liquor. Xylose and xylooligomers are the main five-carbon sugar in the hot water extract, which reached a maximum concentration of 0.016 mol/L, and 0.018 mol/L, respectively. Minor monosaccharides including galactose, mannose, rhamnose, glucose, and arabinose are also obtained during the hot water extraction. Rhamnose is the main six-carbon sugar in the extraction liquor, which has a maximum concentration of 0.0042 mol/L. The variations of acetyl groups and formic acid are investigated due to their catalytic effect on the extraction reactions. Zeroth-order kinetics models are found to be adequate in describing the dissolved solids, acids, xylose, and xylooligomers.

This study assesses the techno-economic and environmental performance of C6 sugars production from softwood (spruce) and corn. Two technologies were considered in the assessment: organosolv of spruce woodchips (2nd generation) and corn wet milling (1st generation). Process models were developed to generate relevant data to assess the technical performance and derive inputs for the economic and environmental assessments. The economic assessment was carried out using Net Present Value (NPV) as indicator, while the environmental assessment followed a prospective cradle-to-gate life cycle assessment (LCA) for 5 impact categories. The results indicate that when organosolv is integrated with an anaerobic digestion unit, the net energy requirements are lower than those of the wet milling process to produce an equivalent flowrate of C6 sugars. Assuming equivalent C6 sugar prices for the two technologies (300 €/t), the corn based technology shows positive NPV (178 M€) and lowest fixed capital investment requirements (55 M€). The organosolv technology (coupled to anaerobic digestion) also shows positive NPV (238 M€) at base case lignin prices (630 €/t), but higher fixed capital investment needs (236 M€). The economics of the organosolv process were found to be highly sensitive to sugar and lignin yields and prices as well as biomass feedstock costs. From an environmental perspective, the organosolv based routes show relatively better performance than corn wet milling, with 3 categories including climate change and non-renewable energy use showing lower impacts and 2 showing potentially higher impacts. Overall, the organosolv process (2nd generation) shows better performance from an environmental point of view in addition to a positive NPV. However, the inherent risks of new technologies and high investments associated with the 2nd generation technologies assessed in this work, mean that significant additional development, coupled with appropriate government support, are likely necessary before full-scale implementation.

Among the various types of agricultural waste, significant amounts of energy can be obtained from woodchips derived from comminuted pruning residues. This study aimed to assess the feasibility of using kiwi orchard clear-cut biomass for energy production. The field trial was conducted in a commercial kiwi (Actinidia chinensis) orchard located in Northwest Italy. We evaluated the biomass yield, woodchip quality, energy consumption, and economic sustainability of this practice. Processed data determined the available biomass to be 20.6 tonnes dry matter ha−1. Woodchip analysis showed a biomass moisture content of 53% and a relatively low heating value of about 7.5 MJ·kg−1. Furthermore, the average ash content was 2.4%. Production cost was 99.6 €·t−1 dry matter, which was slightly less than the market price of 100 €·t−1 dry matter for woodchips. In summary, kiwi clear-cut recovered biomass may be a valid alternative biomass source.

Nitrate-nitrogen (nitrate-N) removal rates can be increased substantially in denitrifying bioreactors with a corn ( L.) cob bed medium compared with woodchips; however, additional organic carbon (C) is released into the effluent. This laboratory column experiment was conducted to test the performance of a postbed chamber of inert plastic biofilm carrier (PBC) after corn cobs (CC) to extend the area of biofilm colonization, enhance nitrate-N removal, lower total organic C losses, and reduce nitrous oxide (NO) production at warm (15.5°C) and cold (1.5°C) temperatures. Treatments were CC only and CC plus PBC in series (CC-PBC). Across the two temperatures, nitrate-N load removal was 21% greater with CC-PBC than CC, with 54 and 44% of total nitrate N load, respectively. However, total organic C concentrations and loads were not significantly different between treatments. Colonization of the PBC by denitrifiers occurred, although gene abundance at the outlet (PBC) was less than at the inlet (CC). The PBC chamber increased nitrate-N removal rate and reduced cumulative NO production at 15.5°C, but not at 1.5°C. Across temperatures and treatments, NO production was 0.9% of nitrate-N removed. Including an additional chamber filled with PBC downstream from the CC bioreactor provided benefits in terms nitrate-N removal but did not achieve C removal. The presence of excess C, as well as available nitrate, in the PBC chamber suggests another unidentified limiting factor for nitrate removal.

New value-added uses for solid municipal waste are needed for environmental and economic sustainability. Fortunately, value-added biochars can be produced from mixed solid waste, thereby addressing solid waste management issues, and enabling long-term carbon sequestration. We hypothesize that soil deficiencies can be remedied by the application of municipal waste-based biochars. Select municipal organic wastes (newspaper, cardboard, woodchips and landscaping residues) individually or in a 25% blend of all four waste streams were used as feedstocks of biochars. Three sets of pyrolysis temperatures (350, 500, and 750 °C) and 3 sets of pyrolysis residence time (2, 4 and 6 h) were used for biochar preparation.The biochar yield was in the range of 21–62% across all feedstocks and pyrolysis conditions. We observed variations in key biochar properties such as pH, electrical conductivity, bulk density and surface area depending on the feedstocks and production conditions. Biochar increased soil pH and improved its electrical conductivity, aggregate stability, water retention and micronutrient contents. Similarly, leachate from the soil amended with biochar showed increased pH and electrical conductivity. Some elements such as Ca and Mg decreased while NO3-N increased in the leachates of soils incubated with biochars. Overall, solid waste-based biochar produced significant improvements to soil fertility parameters indicating that solid municipal wastes hold promising potential as feedstocks for manufacturing value-added biochars with varied physicochemical characteristics, allowing them to not only serve the needs for solid waste management and greenhouse gas mitigation, but also as a resource for improving the quality of depleted soils. Qatar National Research Fund

The research, whose results are presented, is aimed at determination of development of moulds number in wood chips under different storage temperatures. The experiments were carried out with the moisture of samples 65%, 22% and 1%. During the long-term storage the effect of water content in material on development of moulds can be recorded. The risks linked to mould occurrence can be considerably eliminated by reduction of water content.

A hybrid plant that consists of a gasification system, Solid Oxide Fuel Cells (SOFC) and a Simple Kalina Cycle (SKC) is investigated. Woodchips are introduced into a fixed bed gasification plant to produce syngas, which is then fed into an integrated SOFC-SKC plant to produce electricity. The pre-treated fuel then enters the anode side of the SOFC. Complete fuel oxidation is ensured in a burner by off-gases exiting the SOFC stacks. Off-gases are utilized as heat source for a SKC where a mixture of ammonia and water is expanded in a turbine to produce additional electric power. Thus, a triple novel system based on a gasification plant, a SOFC plant and a SKC plant is presented and investigated. The system is called IGSKC (Integrated Gasification SOFC Simple Kalina Cycle). The system layout is studied, and the optimal ammonia-water mole fraction is selected. An electrical efficiency of 58% is achieved; plant size and nominal power are selected based on the required cultivation area.SOFC heat recovery with SKC is compared to a Steam Cycle (SC). Although ammonia-water more accurately fits the temperature profile of the off-gases, the presence of a Hybrid Recuperator enhances the available work in the SC case, resulting in a higher overall thermal efficiency.

Torrefied biomass represents a high quality renewable energy commodity that can be used to substitute fossil fuels such as coal. However, densification processes such as pelletisation is necessary to improve the tradability of “low-dense” torrefied biomass. In this work, two process pathways were assessed for energy and mass balance in making torrefied pellets from softwood chips and qualities of the resulting torrefied pellets were compared. Pathway I involve drying the wood chips, torrefaction, grinding followed by densification. In pathway II, wood chips were dried, ground, densified and finally torrefied. The results showed that it was difficult to bind the torrefied biomass particles and a binding agent was necessary to enable their effective pelletisation with reasonable energy consumption. In contrary, pelletization of raw materials was possible without using binding agents and when the “raw wood pellets” were torrefied, the pellets surprisingly stayed intact and had several promising properties such as higher energy/carbon value, reduced moisture content and higher stability in water. In addition, the pathway II was more efficient in terms of overall energy and material balance.

Thermodynamic and thermoeconomic investigations of a small-scale integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120 kW e have been performed. Woodchips are used as gasification feedstock to produce syngas, which is then utilized to feed the anode side of the SOFC stacks. A thermal efficiency of 0.424 LHV (lower heating value) for the plant is found to use 89.4 kg/h of feedstock to produce the above mentioned electricity. Thermoeconomic analysis shows that the production price of electricity is 0.1204 $/kWh. Furthermore, hot water is considered as a by-product, and the cost of hot water is found to be 0.0214 $/kWh. When compared to other renewable systems of similar scales, this result shows that if both SOFC and Stirling engine technology enter the commercialization phase, then they can deliver electricity at a cost that is competitive with the corresponding renewable systems of the same size.

This paper presents a thermo-economic analysis of an integrated biogas-fueled solid oxide fuel cell (SOFC) system for electric power generation. Basic plant layout consists of a gasification plant (GP), an SOFC and a retrofitted steam-injected gas turbine (STIG). Different system configurations and simulations are presented and investigated. A parallel analysis for simpler power plants, combining GP , SOFC , and hybrid gas turbine (GT) is carried out to obtain a reference point for thermodynamic results. Thermodynamic analysis shows energetic and exergetic efficiencies for optimized plant above 53% and 43% respectively which are significantly greater than conventional 10 MWe plants fed by biomass. Thermo-economic analysis provides an average cost of electricity for best performing layouts close to 6.4 and 9.4 c€/kWe which is competitive within the market. A sensitivity analysis of the influence of SOFC stack cost on the generation cost is also presented. In order to discuss the investment cost, an economic analysis has been carried out and main parameters such as Net Present Value (NPV), internal rate of return (IRR) and Time of Return of Investment (TIR) are calculated and discussed.

The presented research included laboratory scale composting of sewage sludge and woodchips mixtures amended with biochar in 45 L reactor system conducted for 16 days. The effect of biochar amendment on ammonia emission was investigated. The addition of biochar reduced significantly volatilization of ammonia during the first week of the process. Also, the addition of biochar increased temperature and organic matter decomposition.

Forest harvest residues, which include limbs, branches, and tree tops, have the potential to generate energy. This paper uses a life-cycle assessment to determine the energy input-to-output ratios for each unit operation in the use of these residues for power generation. Two preparation options for obtaining the biomass were evaluated. For Option 1, the forest residues were chipped at the landing, while for Option 2 they were bundled and chipped at the power plant. Energy use and greenhouse gas (GHG) emissions were found for power plants sizes ranging from 10 to 300 MW. For power plants with capacities greater than 30 MW, the transportation of either bundles or woodchips to the power plant used the most energy, especially at larger power plant sizes. Option 1 used less energy than Option 2 for all power plant sizes, with the difference between the two becoming smaller for larger power plants. For the life-cycle GHG emissions, Option 1 ranges from 14.71 to 19.51 g-CO 2 eq/kW h depending on the power plant size. Option 2 ranges from 21.42 to 20.90 g-CO 2 eq/kW h. The results are not linear and are close to equal at larger power plant sizes. The GHG emissions increase with increasing moisture content. For a 300 MW power plant with chipping at the landing, the GHG emissions range from 11.17 to 22.24 g-CO 2 eq/kW h for moisture contents from 15% to 50%. The sensitivity analysis showed both energy use and GHG emissions are most sensitive to moisture content and then plant lifetime. For the equipment, both the energy use and GHG emissions are most sensitive to changes in the fuel consumption and load capacity of the chip van and the log-haul truck used to transport either bundles or wood chips to the power plant.

This paper investigated the possibilities of using birch wood chips for fixed-bed downdraft gasification. The preliminary air gasification resulted producer gas with an average composition of 11.5 % CO, 5.4 % CO2, 5.9 % H2, 0.38 % CH4 corresponding to a mean lower heating value of about 2 MJ/kg. The approximate size of woodchips used for gasification was around 11.5 mm for a maximum solid throughput of 0.65 kg/h. The obtained equivalence ratio (ratio between actual air fuel ratio and stoichometric air fuel ratio) as a result of air and biomass feed was close to 0.45 which was stable throughout the test. Producer gas left the gasifier at ca. 150 °C and was diverted for flaring owing to the level of low energy content. Despite availability, the option for gas to generate heat and electricity via integrated gas engine has not been utilized in the present case and remained for further ongoing research.

Biomass has emerged in the renewable energy area with high potential to contribute to the energy needs in both the industrialized and developing countries. The objective of this study is to evaluate and compare the economic feasibility of three different configurations of a woodchips power plant based on the circulating fluidized-bed (CFB) gasification: (1) a gas engine, (2) a gas turbine, and (3) gas & steam turbines. A comprehensive model of the power plant was developed employing the process simulator, Aspen Plus. The economic feasibility was analyzed in terms of the payback period (PBP), return on investment (ROI), and discount cash flow rate of return (DCFROR). It was proposed that the power plant has an economic benefit for plant sizes of over 150 t/d of dry woodchips in all the three cases. The gas engine was a better choice for the power plant sizes smaller than 200 t/d or 22 MW e , while the gas & steam turbines had the highest benefit at big plant sizes over 200 t/d. A sensitivity analysis was performed for the 150 t/d plant to identify key variables that have a strong impact on DCFROR. The total capital investment (TCI) and plant size had a major influence on DCFROR.

This paper presents an exergetic analysis of a fast pyrolysis plant simulated in Aspen Plus, producing crude bio-oil from lignocellulosic feedstock (hybrid poplar woodchips). The simulation includes the drying and pretreatment of the biomass, the pyrolysis reactor, product recovery, and a combustion reactor that provides the process heat. Chemical and physical exergies are determined for all process streams and the exergy destruction is calculated at the component level of the plant. The overall exergetic efficiency of the plant is found to be 71.2%, with the gas-and-char combustor of the plant causing the highest exergy destruction. Relatively high irreversibilities are also calculated in the pyrolysis reactor and the bio-oil recovery section (quench and water cooler), as well as in the dryer and the mill. Further investigation shows considerable potential for improvement when introducing the hot exhaust gases of the combustor directly in the dryer without using part of their thermal energy for preheating the combustion air. This measure increases the overall plant efficiency to 73.2% by reducing the inefficiencies in the dryer and the heat exchangers. Lastly, the contribution of the compressors and pumps to the overall exergy destruction is found to be rather small.