Wood Biofuels Research Articles

Production and trade of wood biofuels in the Asia-Pacific region

Production and trade of wood biofuels in the Asia-Pacific region

Combustion Efficiency of Various Forms of Solid Biofuels in Terms of Changes in the Method of Fuel Feeding into the Combustion Chamber

This study analyzes the combustion of pellets and briquettes made of plant biomass in low-power heating devices powered periodically with fuel being placed on the grate, as well as after modification using an automatic fuel feeding system in the gutter burner. The use of herbaceous biomass in the form of pellets in low-power heating devices with automatic fuel feeding and combustion in a gutter burner is not widely promoted and popular. Therefore, this study used four types of herbaceous waste biomass (wheat straw, rye straw, oat straw and hay) and one type of woody waste biomass (birch sawdust) for testing. The basic chemical characteristics were determined for the raw materials. After appropriate preparation, the selected starting materials were subjected to briquetting and pelleting processes. Selected physical properties were also determined for the obtained biofuels. Biofuels made from birch sawdust had the lowest heat value (16.34 MJ·kg−1), although biofuels made from wheat, rye and hay straw had a slightly lower calorific value, respectively: 16.29; 16.28 and 16.26 MJ·kg−1. However, the calorific value of oat straw biofuels was only 15.47 MJ kg−1. Moreover, the ash content for herbaceous biomass was 2–4 times higher than for woody biomass. Similar differences between herbaceous and woody biomass were also observed for the nitrogen and sulfur content. To burn the prepared biofuels, a domestic grate-fired biomass boiler was used, periodically fed with portions of fuel in the form of pellets or briquettes (type A tests), which was then modified with a gutter burner enabling the automatic feeding of fuel in the form of pellets (type B tests). During the combustion tests with simultaneous timing, the concentration of CO2, CO, NO and SO2 in the exhaust gases was examined and the temperature of the supplied air and exhaust gases was measured. The stack loss (qA), combustion efficiency index (CEI) and toxicity index (TI) were also calculated. The research shows that the use of automatic fuel feeding stabilizes the combustion process. The combustion process is balanced between herbaceous and woody biomass biofuels. Disparities in CO2, CO and Tgas emissions are decreasing. However, during type B tests, an increase in NO emissions is observed. At the same time, the research conducted indicates that the combustion of herbaceous biomass pellets with their automatic feeding into the combustion chamber is characterized by an increase in combustion efficiency, indicating that when the combustion process is automated, they are a good replacement for wood biofuels—both pellets and briquettes.

Wood combustion nanoparticles emitted by conventional and advanced technology cordwood boilers, and their interactions in vitro with human lung epithelial monolayers

Biomass-burning boilers and stoves are widely used in many parts of the world, producing combustion emissions linked with health risks. Combustion emission nanoparticles (NPs) were collected from four representative wood burning boilers using oak cordwood at specific times in the burn cycle. The morphology and composition of the NPs was characterized using transmission electron microscopy and energy dispersive X-ray analysis. To determine the degree of NP cytotoxicity with human lung tissue, the combustion NPs were introduced to incubated lung bronchial epithelial monolayers (NCI-H292) in vitro at doses of 0.1 × 10-6 and 3.0 × 10-6 kg/L for 2 and 4 h. Histochemical analysis showed that cell death increased by a factor of 3.5 for both doses after 4 h when compared to the control. Ultrapure NPs prepared by wet chemical methods were also introduced to the epithelial lung cells for similar doses and exposure times and the cultures exhibited significantly reduced mortality. Electron microscopy was used to study the mechanism of cell mortality for the synthesized and combustion-based NPs by examining how the NP byproducts interacted with individual cell organelles. It was found that cell survival was strongly correlated with the absence of contaminants (salts, heavy metals, poly aromatic hydrocarbons) associated with the NPs entering the cells. Synthesized NPs consisting of pure carbon were relatively well tolerated and could be excreted without damaging the cell ultrastructure. Thus, careful removal of extraneous contaminants by controlling the burn cycle with a catalyst is essential to minimize the health and environmental effects of wood biofuel combustion. In better words, optimized advanced technology wood-burning boilers and stoves can provide a CO2-neutral energy source and significantly contribute to a future where fossil fuels have a reduced role.

Теплотворная способность древесины сосны в культурах северотаежного лесного региона

Calorific value of plants is an important characteristic for evaluation of material cycles and energy conversion in forest ecosystems, as well as a qualitative characteristic of plant raw materials as fuel. Wood biofuel is increasingly used in the production of thermal energy, in this regard, it is important to study the calorific value of wood, as well as the conditions for growing high-quality raw materials. The research purpose is to identify the dependence of the calorific value of pine wood in crops on its macroscopic structure, the assimilation apparatus characteristics, density and height of the stand. Small, medium, and large not damaged model trees without pathologies were selected on temporary sample plots. Cores from which were taken with an increment borer at a height of 1.3 m to measure radial growth on the semi-automatic complex Lintab-6 with an accuracy of ±0.01 mm. The calorific value of pine wood was determined in an absolutely dry state using an automated bomb calorimeter ABK-1V. To study the influence of the assimilating apparatus on the wood calorific value, needles of all ages were selected from the middle branch of the model tree crown. Cross sections were prepared from the middle part of a needle using a sledge microtome MS-2. Histological elements of a needle were measured by the Axio Scope.A1 microscope using the IMAGE-PRO INSIGHT 8.0 software. The average heat capacity of pine wood in heath-lichen pine forests is (20 731±133) J/g; in cowberry pine forests – (20 618±141) J/g; in bilberry pine forests – (20 513±104) J/g at a stand density from 1160 to 3806 pcs/ha. The highest pine wood heat capacity is found in heath-lichen pine forests with the density of stand 5021 pcs/ha. The increased pine wood heat capacity in pine forests with high stand density is due to a reduction in the number of needles on the branch (r = –0.75) and an increase in the diameter of resin channels (r = – 0.88). The influence of the average stand height and the annual layer structure on the calorific value of pine wood was found.

Logistic characteristics and requirements of Swedish wood biofuel heating plants

The demand for wood biofuel for district heating plants and combined heat and power plants (CHPs) has increased, caused by an increase in both the number and size of CHPs. This places large demands on the logistics system supplying these plants with fuel, with a particular interest in the use of alternative modes of transport such as rail and sea. The aim of this paper is to identify the industry actors’ requirements, constraints, and preferences regarding the wood-biofuel supply chain and to identify the logistical challenges this entails, as well as how this impacts the opportunity for an increased use of alternative transport solutions. A survey was sent to all Swedish CHPs, combined with six interviews with transport companies, terminal operators, and forest companies. The study shows that the industry has a local focus that limits potential logistics and sourcing solutions. It is also challenged by urban sprawl, with expanding residential areas close to the CHPs putting further constraints on the operations. Significant variations in fuel demand, depending on unpredictable outside temperature and seasonal variation, is a further challenge. The low density of the fuel has a negative impact on transport costs and introduces a trade-off between chipping close to the forest to increase density versus more efficient chipping at the CHP. Intermodal transport only used by large plants, driven by a shortage of local fuel.

Possibilities of using biofuel ash in the cultivation of spring barley

Wood biofuel ash is a complex and heterogeneous mixture of inorganic crystalline and amorphous minerals together with organic matter. Biofuel ash is usually enriched with K, P, Ca and Mg, which are essential macronutrients for plant growth. Currently, a large proportion of biofuel ash is disposed of in landfills. However, ash processed into granular products can be used as a stand-alone or additional mineral fertilizer in agriculture. The aim of the research is to determine the chemical composition of biofuel ash and evaluate its suitability for the production of ash granules; also to evaluate the yield of spring barley grain and straw fertilized with bulk and granular biofuel ash, and the correlation between the yield and the amount of K2O applied by different fertilization products. The experiment was carried out in 2017–2018. Concentrations of heavy metals (Cr, Pb, Ni, Cd) and microelements (Zn and Cu) in wood biofuel ash did not exceed the permissible norms, and from them it was possible to produce fertilization products (ash granules) and use them in a vegetation experiment. During the experiment, it was found that the fertilization products significantly (P < 0.05) increased the yield of grown spring barley grains and straw in both years of the study, and the performed correlation regression analysis was positively strong in both years of the study (P < 0.01). The yield of spring barley increased with the increase of K2O content in fertilizer products.

The energy and ecological performance of the hot water boiler burning linden bark and wood briquettes

The North-West of Russia possesses huge wood resources reserves, therefore the issues of the most efficient use of wood biomass are relevant for this region. The implication of wood biofuels into fuel and energy budget provides an opportunity to reduce the negative impact of power industry facilities on the environment and preserve the potential of non-renewable fuels for future generations. An effective way of the complex solution of energy and ecological problems, while providing heating loads for consumers, is the use of modern devices operating on solid biofuel. Technical analysis of foreign and domestic high-performance heating units has great importance. The aim of the research is an evaluation of energy and ecological performance of the Firematic 60 hot water boiler burning bark of linden, briquettes from wood sanding dust and sawdust of plywood processing, as well as briquettes obtained by pressing softwood sawdust and shavings. The paper presents thermotechnical characteristics of burning biofuels and the components of boiler heat balance and gaseous emission from the burning linden bark and briquettes. Particulate matter emission and content of soot were studied. The shape and composition of soot particles were determined with a Zeiss SIGMA VP electronic scanning microscope. Presented data were obtained using equipment of the Research Center of Power Engineering Innovations. The results of the comprehensive energy audit have shown that the Firematic 60 boiler provides high technical and economic performance with minimum emission of harmful substances to the atmosphere. It can be used for low-rise buildings heat supply in weather conditions of the Arctic region especially.

Versatile grinder technology for the production of wood biofuels

The exploitation of wood biomass for thermal energy production often represents an effective complementary source to petroleum, especially where there is the availability of extended forests. Focusing the attention on household plants, the wood pellet currently constitutes a widespread biofuel, which however is characterized by non-negligible production costs. Wood microchips constitute a recently developed alternative, which compensates its inferior characteristics by an easier production process. To obtain these biofuels, the particle size reduction is crucial, because it sensibly influences the power consumption of the drying processes, as well as the raw material supply strategies. In this context, this paper presents an innovative grinding technology, which can be exploited to produce wood particle sizes for both wood pellets and microchips production. In particular, the prototype of the grinder and the experimental plant are shown, which have been used for performing preliminary biofuel production tests. The main design characteristics of the prototype are provided, together with preliminary experimental results that provide first evidences about the potentialities of the proposed wood grinding technology.

Оценка производства и потребления древесного биотоплива в Республике Коми

Оценка производства и потребления древесного биотоплива в Республике Коми

How Wood Fuels’ Quality Relates to the Standards: A Class-Modelling Approach

The quality requirements of wood biofuels are regulated by a series of harmonized international standards. These standards define the technical parameter limits that influence the quality of solid biomass as a fuel. In 2014 the European reference standard for solid biofuel was replaced by the International ISO standard. In the case of wood chips, the main difference between the European and International standards is the definition of particle size distribution classes. In this context, this study analyses the quality of wood chips and its variation over the years according to the “former” (EN 14691-4) and “in force” (ISO 17225-4) standards. A Soft Independent Modelling of Class Analogy (SIMCA) model was built to predict the best quality of wood chips and to clarify the relationship between quality and standard parameters, time and changes in the standard regulations. The results show that, compared to the EN standards, classification with the ISO standards increases the samples belonging to the best quality classes and decreases the not classified samples. Furthermore, all the SIMCA models have a high sensitivity (>90%), reflect the differences introduced to the quality standards and are therefore suitable for monitoring the quality of wood chips and their changes.

Thermogravimetric and kinetic analyses of the thermal decomposition of fuel wood

The results of studies of the thermal transformations of granulated wood biofuel performed by thermogravimetry and differential scanning calorimetry in an atmosphere of argon at heating rates of 5, 10, 20, and 30 K/min are reported in this paper. The results of the analysis were used for the determination of the preexponential factor and activation energy of the thermal decomposition of wood biofuel based on the Kissinger, Kissinger–Akahira–Sunose, and Ozava–Flynn–Wall isoconversion model-free methods. The values of activation energy for the release of volatile substances in the course of the thermal decomposition of wood granules varied in ranges of 87–250 and 76–242 kJ/mol.

Thermal degradations of wood biofuels, coals and hydrolysis lignin from the Russian Federation: Experiments and modeling

The thermal degradation of wood biofuels (spruce, pine), of coals from different fields of the Russian Federation and of hydrolysis lignin is investigated using a thermogravimetric analyzer under different heating conditions and under non-oxidative or oxidative atmospheres. The samples are indeed submitted to a linear temperature ramp of 10K/min or to a temperature ramp of 200K/min up to a residence temperature between 250 and 450°C where they are maintained during 4h (isothermal conditions). The values of the kinetic parameters are determined for these different samples in both thermal conditions, either using the differential isoconversional method or by means of an Extended Independent Parallel Reaction (EIPR) model. The values of the kinetic parameters obtained with this EIPR model for spruce trunk are also compared with that of its main constituents (hemicellulose, cellulose and lignin).

АНАЛИЗ ТЕРМОГРАВИМЕТРИЧЕСКИХ И КИНЕТИЧЕСКИХ ДАННЫХ РАЗЛИЧНЫХ ВИДОВ ДРЕВЕСНОГО БИОТОПЛИВА СЕВЕРО-ЗАПАДНОГО РЕГИОНА РОССИЙСКОЙ ФЕДЕРАЦИИ

АНАЛИЗ ТЕРМОГРАВИМЕТРИЧЕСКИХ И КИНЕТИЧЕСКИХ ДАННЫХ РАЗЛИЧНЫХ ВИДОВ ДРЕВЕСНОГО БИОТОПЛИВА СЕВЕРО-ЗАПАДНОГО РЕГИОНА РОССИЙСКОЙ ФЕДЕРАЦИИ

Opportunities and challenges for rail transport of solid wood biofuel

The use of solid biofuel for energy in heating plants has increased drastically during the last decades. This substantial and increasing demand has placed focus on delivering biofuel to the plants, as logistics issues are considered one of the key challenges for further increased use of biofuel. Problems in sourcing enough fuel locally due to the increasing size of power plants and environmental concerns has sparked an interest in using multimodal road-rail transport as a cost effective and environmentally friendly way of long-haul transport. A case study is performed at a Swedish district heating plant to investigate the potential of introducing multimodal transport. Extensive calculations are performed in the design and operation of a multimodal system, showing both costs and CO2 emissions. This is analysed in relation to key logistical challenges in the industry. A best case scenario is identified. Conclusions are that the potential for multimodal transport is greatest among the largest plants with large volumes to achieve high resource utilisation of the transport equipment. A shift from road to multimodal transport is facilitated by that a large share of the current road transport flows already pass through a terminal, which improves multimodal transport competitiveness against road transport as this reduced the cost difference. This study leads to better understanding of the strengths and weaknesses of multimodal biofuel transport and has practical implications for anyone in the process of designing such systems.

Business models for sustainable biofuel transport: the potential for intermodal transport

The use of solid wood biofuels for energy production in heating plants has increased drastically during the last decades. Great interest has been shown in replacing unsustainable road transport of wood fuel with more sustainable intermodal transport. This paper maps the common business models for biofuel transport in Sweden and suggests how these models may be developed to accommodate intermodal transport. A view of the biofuel supply chain as five overlapping networks (industry, material, operations, transport, and infrastructure) connected by four transaction markets (sourcing, operations, transport, and traffic) have been used. Four typical business models have been found: Regional/National Biofuel Company, Local Biofuel Company, Heating Plant Own Account, and Wood Processing Industry. Cooperation and vertical integration among the actors are important to reach the large transport volumes required for intermodal transport. Key issues to increase the intermodal potential are: increased vertical integration and cooperation, sharing of transport resources and infrastructure, joint purchases, outsourcing to expert actors, building trust and open communication, and not underestimating the complexity of intermodal transport. The results have implications for any actor interested in developing intermodal transport or policy measures. The contribution includes the new approach of developing business models by using the five-layer network-market model.

Secondary cell walls built with speed

Plant Science Plant cell walls provide the cellulose that is integral for wood, cotton fiber, and many biofuels. Cellulose is synthesized outside the cell membrane by cellulose synthase enzymes. Much of the secondary cell wall, responsible for the sturdiness of wood, is formed by xylem cells embedded in the core of the plant. Watanabe et al. leveraged ectopic expression to bring xylem-style cellulose synthase activity to the epidermal surface of the plant (see the Perspective by Schneider and Persson). Combining this improved accessibility with fluorescent tagging showed that secondary cell walls are built faster than primary cell walls, perhaps due to increased velocity and density of cellulose synthase complexes. Science , this issue p. [198][1], see also p. [156][2] [1]: /lookup/doi/10.1126/science.aac7446 [2]: /lookup/doi/10.1126/science.aad3200

Investigation of thermal degradation of different wood-based biofuels of the northwest region of the Russian Federation

The thermal degradation of different wood biofuels collected in the Arkhangelsk region (northwest of the Russian Federation) was investigated in order to extract their kinetic parameters. Thermogravimetric analysis was carried out for small samples under inert atmosphere or air. These samples were heated from 20 to 1300 � C under three heating rates of 5, 10 or 20 � C min -1 . The mass loss rates were measured during the drying, devolatilization and char combustion processes. Average values of the activation energies were determined using Friedman's and Ozawa- Flynn-Wall's methods under inert atmosphere and air. The morphological analysis of raw samples and of the corre- sponding chars was also performed. Pore development presents an effective impact on char reactivity. These experimental results and the kinetic data obtained in this work should be considered for the simulation of the pyrolysis and combustion processes of different biofuels in industrial devices.

Energy and moisture losses during poplar and black locust logwood storage

The main problem with firewood production is the same as for other wood biofuels: storage. Usually, firewood is stored in logwood. The goal of this study was to determine the drying storage dynamics of logwood used for firewood production under the typical forest practice of southern Europe. Storage dynamics were evaluated for two different tree species (poplar and black locust) with logwood disposed in uncovered piles for a period of 180days (March–September). In this study, the effect of the diameter of logs and their position inside the pile on wood drying was evaluated. This evaluation was performed considering the main key drying physical parameters — temperature (T), moisture content (MC), heating value (HV) and dry matter (DM).The study found that initial values of key parameters were different for both forestry species, but at the end of the storage period the values were considered to be similar. No statistically significant differences were pointed out between logs with different diameter sizes and different positions in the pile. For this reason, drying logwood in uncovered piles can be considered a good storage method irrespective of forestry species, the diameter of logs and the position of logs in the pile.

Определение наличия искусственных компонентов в древесном биотопливе

Определение наличия искусственных компонентов в древесном биотопливе

Анализ методик оценки физико-механических и тепловых характеристик древесных пеллет

The paper discusses the methodology for assessing characteristics in relation to this type of wood biofuel. Part of the methods is adopted by the national standards of the Russian Federation, the other part is proposed because of the lack of regulations. Interest in solid biofuels in the last decade has increased steadily, a rather stable market was formed, and there are its own leaders. Until not long ago the absence of legally approved methods for determining physical, mechanical, thermal, chemical characteristics made significant challenges for the development of this promising trend of industrial production, both in Europe and in the Russian Federation.