Wood Pellets Research Articles

Evaluation Indicator for the Spontaneous Combustion of Biomass Fuel Pellets and Its Self-Ignition Control

ABSTRACT To investigate the spontaneous combustion characteristics of biomass fuel particles, spontaneous combustion processes of 10 biomass samples were simulated by programmed-heating and continuous oxidation experiments. Analysis results indicated that during the very initial stage of spontaneous combustion (<90 °C), each biomass fuel particles merely yielded CO at 0–20 ppm, while the subsequent exponential growth of gas emissions tended to exhibit a significant variation on spontaneous liability. Due to the diversity of biomass material sources, its spontaneous combustion tendency is not only determined by internal properties, but also influenced by external factors such as particle size, ventilation rate, moisture, etc. There are many factors affecting the spontaneous combustion tendency, which cannot be analyzed accurately and quantitatively. Therefore, it is necessary to propose a stable indicator based on thermal analysis to objectively evaluate the tendency of biomass spontaneous combustion. A scientific index was proposed to precisely assess the spontaneous combustion tendency of biomass materials. Specifically, the activation energy (E) at the O2 gain stage was adopted as the priority criterion: If E < 70 kJ/mol, the biomass was defined to be highly flammable; if 70 ≤ E ≤ 80 kJ/mol, the biomass was considered to be prone to self-ignition; and if E > 80 kJ/mol, the biomass was regard as non-spontaneous combustion. Besides, data from cross-point temperature tests fundamentally support the reliability of mentioned evaluation methodology. In fire-extinguishment experiments, a conventional approach, such as suffocate by self-extinguishing, only reduced the temperature to 99.9–238.7°C. The comparison of extinguishing materials such as gaseous N2/liquid nitrogen, CO2, and C3HF7 revealed that extinguishing fire with C3HF7 exhibited a dramatic advantage at burning temperature > 500°C. However, fire extinguishing with CO2 was more suitable for the spontaneous combustion ignition of biomass at temperature ≤ 300°C.

Livestock Manure Compost Mixed with Biochar: Efficient Pelleting and Pellet Production Characteristics

Biochar is difficult to make pellets on its own. The pelleting of biochar mixed with livestock manure compost could have the following advantages: (1) use compost as a binder, (2) reduce the moisture content of compost for pelleting by simply mixing without drying, and (3) promote the application of biochar for carbon sequestration by simultaneous application with agricultural machinery for chemical fertilizers while preventing dust pollution and additional work for the farmer. Fertilizer pellets need to be produced in an economical manner. Therefore, we empirically examined the productivity of pelleting using a roller die pellet mill, which is characterized by high throughput and is commonly used in the mass production of multifertilizer and wood pellets. Although a feedstock with 25% biochar mixed with cattle manure compost produced fewer pellets than a feedstock consisting of only compost, the energy input per unit of production remained the same. The results suggest that the addition of biochar may not increase GHG emissions during the production of this new material. Durability and wettability showed similar or higher values in the mixed pellets, indicating that the new material can be used as a fertilizer in the same way as cattle manure pellets.

Consumer Preferences for Wood-Pellet-Based Green Pricing Programs in the Eastern United States

Co-firing wood pellets with coal is an attractive alternative energy generation method with economic, social, and environmental benefits for the US energy generation sector. One way to sustainably use wood pellets for co-firing is to create consumer-supported green pricing programs (GPPs). Our study surveyed residents of five states (Alabama, New Jersey, New York, Pennsylvania, and Virginia) to investigate preferences for the attributes of a hypothetical GPP. The study applied the Best Worst Choice method, which employs the Best Worst Scaling (BWS) and binary choice (BC) task. The BWS analysis showed that residents of all five states most value the flexibility of contracts, the location of energy generation, and the reduction of carbon emissions as attributes of GPPs. The BC analysis, however, showed that residents are willing to pay a premium for length of contract, followed by reduction of carbon emissions and variability of payments. This study shows that the adoption of optimal GPP attributes can create real customer value. The success of GPPs will depend on increasing enrollment and public support; hence, the next step will be to increase awareness levels and green consciousness through sensitization in the form of public education exercises and media campaigns. Such measures will serve to inform and educate residents on the benefits of GPPs and lessen the gap between intrinsic value and willingness to pay for select attributes.

Biomass Pellet Fuel Production and Utilization in Ghana: A Review

Biomass Pellet Fuel Production and Utilization in Ghana: A Review

Utilization of wood pellet for industrial use

The use of wood pellets for industrial uses has grown significantly in recent years due to their sustainability, cost-effectiveness, and environmental advantages. Wood pellets have a wide range of industrial applications, including energy generation, heating, and manufacturing processes. They made from compacted sawdust and wood waste provide a renewable alternative to traditional fossil fuels, helping to cut greenhouse gas emissions and combat climate change. In the energy industry, wood pellets are a feasible substitute for coal in power plants, allowing for the transition to greener energy sources. Their stable quality and high energy density make them an appealing option for power generation, especially in areas trying to meet renewable energy requirements. Furthermore, wood pellets are rapidly being used in industrial heating applications such as boilers and furnaces across a wide range of industries, including manufacturing, food processing, and agriculture. Their efficient combustion properties and dependable supply chain make them an affordable option for enterprises looking to save operating expenses and carbon footprints. Technological developments in the pellet production process, along with governmental frameworks that encourage sustainable practices and renewable energy, are anticipated to propel market expansion. In summary, the use of wood pellets in industry presents a strong way to satisfy the rising need for environmentally friendly heating and energy sources. Wood pellets have the potential to be a key player in the shift towards a more sustainable industrial landscape by utilizing its renewable nature and environmental advantages.

Adoption of renewable heating systems and thermal energy communities in the Netherlands: An empirical study

Renewable heating systems (RHS), such as solar thermal, geothermal, heat pumps, wood pellets, biomass, are essential to reduce dependence on fossil fuel-based heating systems and resulting CO2 emissions. Despite their benefits in terms of CO2 emissions, the widespread adoption of RHS has yet to be achieved. This paper aims to get insights into the intention to adopt RHS in the Netherlands For this purpose, it designs and conducts a survey based on the extended version of the theory of planned behavior, with five components: attitude, subjective norms, perceived behavioral control, personal norms, and descriptive norms. The survey also includes questions on participation in a thermal energy community. The results show that several factors affect individuals’ intention to adopt RHS. Many individuals in the Netherlands have a positive attitude toward adopting RHS, which is primarily caused by environmental concerns and wanting energy independence for their country. However, the majority of individuals think that they do not have the knowledge, financial means, or time to adopt RHS. Also, individuals who feel strong moral values and responsibilities are more likely to adopt RHS. Most individuals are willing to participate in a thermal energy community, and prefer participating in an energy community over adopting RHS individually. Based on these insights, a number of recommendations are made to stimulate the adoption of RHS in the Netherlands, such as taking into account moral norms, introducing policies to incentivize thermal energy communities, and addressing issues of injustice.

Effect of the Addition of Elderberry Waste to Sawdust on the Process of Pelletization and the Quality of Fuel Pellets

This paper presents the results of a study on the process of the pelletization of pine sawdust with the addition of herbaceous waste from elderberry, in the working system of a pellet press with a flat matrix, in the context of producing fuel pellets. Based on the research, the impact of the addition of herbal waste in the form of elderberry waste on the granulation process of pine sawdust and the assessment of the quality of the obtained pellets were determined. The addition of herbaceous waste from elderberry to pine sawdust had a beneficial effect on the kinetic durability of the obtained fuel pellets, with an increase of up to approximately 1.3% (from 98.03 to 99.31%). Based on the obtained results, it can be concluded that the mechanical strength of all the tested pellets is higher than 97.5%, which is consistent with the ISO 17225-1:2021-11 standard. The bulk density of pellets with the addition of herbaceous waste from elderberry increased (from 649.34 to 658.50 kg∙m−3) as did their density (from 1231.38 to 1263.90 kg∙m−3). The addition of herbaceous waste from elderberry in amounts ranging from 10% to 20% did not have a significant effect on the power requirements of the pelletizer, which decreased compared to the pelletization process of pure pine sawdust. The percentage of this decrease compared to the pelleting process with pure pine sawdust was approximately 10%. The addition of herbaceous waste from elderberry to pine sawdust slightly reduces the energy value (i.e., the heat of combustion and the calorific value) of the obtained pellets. The addition of 30% elderberry waste resulted in a decrease in the heat of combustion from 20.27 to 19.96 MJ·kgd.m.−1, while the calorific value of the pellets decreased from 19.98 to 18.69 MJ·kgd.m.−1 compared to pine sawdust pellets. Hence, adding herbaceous waste from elderberry seems to be a good way of managing large amounts of waste of this kind generated in herbal processing plants. This method of waste management opens new perspectives towards more sustainable and economically effective energy production.

Co-Gasification of Pistachio Shells with Wood Pellets in a Semi-Industrial Hybrid Cross/Updraft Reactor for Producer Gas and Biochar Production

The possibilities of pistachio shell biochar production on laboratory-scale gasification and pyrolysis devices have been described by several previous studies. Nevertheless, the broader results of the pistachio shell co-gasification process on pilot-scale units have not yet been properly investigated or reported, especially regarding the detailed description of the biochar acquired during the routine operation. The biochar was analysed using several analytical techniques, such as ultimate and proximate analysis (62%wt of C), acid–base properties analysis (pH 9.52), Fourier-transform infrared spectroscopy (the presence of –OH bonds and identification of cellulose, hemicellulose and lignin), Raman spectroscopy (no determination of Id/Ig ratio due to high fluorescence), and nitrogen physisorption (specific surface 50.895 m2·g−1). X-ray fluorescence analysis exhibited the composition of the main compounds in the biochar ash (32.5%wt of Cl and 40.02%wt of Na2O). From the energy generation point of view, the lower heating value of the producer gas achieved 6.53 MJ·m−3 during the co-gasification. The relatively high lower heating value of the producer gas was mainly due to the significant volume fractions of CO (6.5%vol.), CH4 (14.2%vol.), and H2 (4.8 %vol.), while hot gas efficiency accomplished 89.6%.

Fuel Wood Pellets Produced from Sawdust of Scots Pine Mature and Juvenile Wood: Self-Heating and Off-Gassing Tests at Industrial Scale

This study investigated self-heating and off-gassing of Scots pine (Pinus sylvestris) wood pellets made from sawdust generated from separated mature and juvenile wood. The pellets were produced at an industrial scale and stored in large piles of about 7.2 tonnes. The production process involved drying the sawdust using three different methods and to varying moisture contents. The results indicated significant influences of both raw material type (F(6) = 61.97, p < 0.05) and drying method (F(2) = 65.38, p < 0.05) on the self-heating of the pellets. The results from the multiple regression analysis further showed that both the raw material type and pellet moisture content significantly influenced the temperature increase, with strong correlations observed for pellets produced using low-temperature drying (F(3, 14) = 83.52, multiple R2 = 0.95, p < 0.05), and medium temperature drying (F(3, 13) = 62.05, multiple R2 = 0.93, p < 0.05). The pellets produced from fresh mature wood sawdust were found to be more prone to self-heating and off-gassing while steam drying the sawdust at high temperature and pressure led to a significant reduction in heat and gas generation across all materials. The heightened self-heating and off-gassing in mature wood pellet can be attributed to a higher proportion of sapwood in the raw material. The probable explanations to the observed differences are in line with biological mechanisms for self-heating and off-gassing, as well as the chemical oxidation of fatty and resin acids.

Evaluation of physicochemical properties and combustion behavior of biomass refuse-derived fuel

Recently, a 125 MW biomass power plant in South Korea has been operating annually using 600,000 tons of wood pellets as fuel, producing approximately 6,000 tons of biomass refuse-derived fuel (BRDF) each year. Owing to challenges in pulverizing biomass, large particles are introduced into the boiler furnace during power generation. However, their size hinders complete combustion, and approximately 1.0 % of the fuel input to the boiler descends to the bottom and is subsequently collected in the ash hopper; it corresponds to BRDF. This study evaluated the recyclability and applicability of BRDF in boilers by comparing its fuel properties with those of raw wood pellets (RWP), torrefied wood pellets (TWP), and coal. Furthermore, we analyzed and assessed the physicochemical properties and fundamental combustion characteristics using the thermally treated biomass grindability index (TTBGI), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The fixed carbon content of BRDF increased, whereas the volatile matter content decreased compared with that of RWP. The H/C and O/C atomic ratios of BRDF were similar to those of coal, and the higher heating value (HHV) of BRDF was improved compared with the other samples. Scanning electron microscopy (SEM) images confirmed significant pore development in the BRDF, and BET analysis indicated an increase in the specific surface area. The TTBGI measurements indicated improved grindability of the BRDF and increased lignin content. In particular, Cmean (%/min) and Cmax (%/min) increased compared with RWP, and the combustion characteristics of the BRDF improved. Therefore, this study suggests that BRDF has the potential to be utilized as a fuel in existing boilers.

Elimination of indigo carmine in water by Pinus patula biochar: Adsorption process optimization, kinetics and isotherms

The textile industry causes major pollution to water bodies due to the discharge of dye-containing wastewater, such as indigo carmine (IC). Biochar has been used to treat organic pollutants like dyes because of its pore structure and surface area, as well as the functional groups contained, low cost, and sustainability of this material. In this study, biochar derived from Pinus patula wood pellets was used to assess its efficiency in the elimination of IC in water. Under optimal conditions of pH, biochar dose, and particle size (3, 13.5 g/L, and 300–450 µm, respectively), a 99% removal of a 25 mg/L solution of IC was achieved. Furthermore, studies on dissolved organic carbon (DOC) revealed that Pinus patula biochar contributed to a 73.8% reduction in the organic matter present in water. The IC adsorptive process was described by the pseudo-second order kinetic and the Freundlich isotherm models. Chemical and physical adsorption mechanisms were associated with the uptake of IC by Pinus patula biochar. Hydrogen bonding, electrostatic attraction, π-π interactions, and pore-filling were regarded as the possible mechanisms involved in the adsorption system. Pinus patula wood pellets biochar was shown to be an efficient adsorbent to remove dyes from water.

The Initial ash deposition formation in horizontal combustion reactor for blending torrefied biomass wood pellets and coals

In response to global warming, the world power plant plans to consistently phase out coal-fired power generation or replace coal with biomass such as wood pellets. However, when the biomass is used itself as a fuel, it is hard to be grounded because of the internal structure. To solve these problems of biomass the torrefaction is the one of the technologies which can enhances the grindability and energy density of the biomass. In order to confirming the utility of this biomass, the combustion characteristics should be analyzed, especially ash formation in the boiler. In this study, these characteristics according to the torrefied wood pellet blending ratio were analyzed using horizontal combustion reactor(HCR) and a scanning electron microscope with energy dispersive spectrometer (SEM-EDS). The SEM-EDS analysis could confirm that the initial ash deposition layer was formed predominantly by ash components had a significant effect on the growth of ash. Furthermore, the tendency of ash deposition with respect to torrefied biomass blending has been studied, along with discussions on the mechanism of ash deposition with the substances composing ash in blending cases.

Comparing Wood Chip Quality from Different Sources across the Southeastern United States

Abstract Global use of renewable energy has risen over the past few decades because of international energy policy changes, new legislation, and an effort to create a more sustainable energy source for a rapidly growing global population. One of these renewable energy sources is biofuels, specifically in the form of wood pellets created from wood chips. Wood pellet manufacturers in the southeastern United States must adhere to rigid quality-control standards of the European markets where their pellets are shipped and consumed. Thus, there is a need to improve our understanding of the factors that influence the quality of the source materials. Higher heating value (HHV), moisture content (MC), ash content, elemental composition, and size stratification are all important quality factors to consider when analyzing wood chips. Variations in these quality factors can cause longer drying times, blockages in feed systems, excess waste, and fluctuations in energy output. The objective of this study was to quantify these quality factors across multiple sources of wood chips. Softwood and hardwood in-woods chip samples as well as softwood mill residual chips were collected from thinnings and clear-cuts across the southeastern United States. Softwoods had a greater HHV and MC than hardwood chips, with 18,949 kJ/kg and 18,242 kJ/kg, respectively. Softwood thinnings had the highest HHV and lowest ash content. However, only 4 of the 60 samples analyzed were from softwood thinnings. This study provides an overview of the variation in wood chip quality across the southeastern United States.

Life Cycle Assessment of Using Firewood and Wood Pellets in Slovenia as Two Primary Wood-Based Heating Systems and Their Environmental Impact

Sustainable use of biomass energy sources can reduce dependency on fossil fuels. Wood biomass is the primary source for heating in Slovenia, with firewood and wood pellets having the highest share. Slovenia’s largest consumers of wood fuels are households primarily using wood from their forests or imported wood pellets. This research used a life cycle assessment to analyze and evaluate the environmental impacts of using firewood and wood pellets for household heating in Slovenia for the first time. The results showed that wood logs have a considerably greater effect on stratospheric ozone depletion, ozone formation, and fine particulate matter (PM) formation. The impact on global warming was lower due to short transportation distances and using log boilers with high combustion efficiency (0.016 and 0.041 kg CO2 eq for wood log and wood pellet combustion, respectively). An increase in transportation distance from 100 km to 1000 km resulted in an 84.9% increase in the values for the categories ozone formation and human health, a 120.4% increase for fossil resource scarcity, and a 102.4% increase in global warming, supporting the premise that short distribution routes are necessary for more sustainable use of the energy source.

Application of Near Infrared Spectroscopy for the Detection of Chemically Treated Pellets Unsuitable for Combustion

The relevant growth of the wood pellet market in Europe in the last decade led to an increased focus on solid biofuel as a necessary and available renewable resource for energy production. Among biofuels, wooden pellets are among the most widespread for domestic heating. Therefore, monitoring the qualitative properties of commercialized pellets is crucial in order to minimize the amount of harmful emissions in residential areas. Standard ISO 17225 sets threshold values for the chemical and physical properties that commercialized biofuels must fulfil. Specifically, ISO 17225-2 defines that pellets for residential use must be produced from virgin wood, but no method is proposed to assess the actual origin of the material, leading to the risk of the commercialization of pellets made up from chemically treated materials. This study proposes a model obtained via near infrared spectroscopy analyses and chemometrics methods, such as classification, to rapidly assess whether pellets are made up of virgin or chemically treated wood. The result suggests the effectiveness of NIRs for the detection of non-virgin pellets with an accuracy greater than 99%. Furthermore, the model appeared to be accurate in the assessment of both milled and intact pellets, making it a potential in-line instrument for assessments of pellets’ quality.

Emission Models for Selected Harmful Substances Emitted During Low-Temperature Combustion of Wood Pellets

Emission Models for Selected Harmful Substances Emitted During Low-Temperature Combustion of Wood Pellets

Soft System Methodology Approach: Case Study of Renewable Energy Development of Wood Pellets as an Implementation of a Circular Economy

The development of wood pellets as a sustainable energy source derived from biomass waste has not significantly increased over the past few decades, despite a rise in demand for and sales of its products worldwide. Several variables contribute to the intricate issue of creating wood pellets from biomass waste as a renewable energy source, including the roles and responsibilities of various stakeholders, including the government, financial institutions, academia, the manufacturing sector, and non-governmental organizations. This article uses a waste management model that employs the Soft System Methodology (SSM) approach to assess the challenge of producing wood pellets from biomass waste as a renewable energy source and possible solutions. Data and information on the development of wood pellets as a renewable energy source derived from biomass waste were acquired through a literature review and in-depth interviews with specialists. The study’s findings demonstrate that using the SSM technique leads to a conceptual model that depicts the interactions between sub-elements to enhance the development of wood pellets as a biomass waste-derived renewable energy source. This concept was developed to lessen any adverse effects and enhance the processing of biomass waste. The success of goals is determined by the importance of each actor’s role and the collaboration of other actors, including local, national, and corporate governments. The Ministry of Environment and Forestry is the primary stakeholder and has a say in policy and program formulation. The Ministry of Industry, Energy and Mineral Resources, financial institutions, and other relevant organizations can help with this effort.

Economic and Sustainability Comparative Study of Wood Pellets Production in Portugal, Germany and Sweden

During the last decade wood pellets consumption grew rapidly. In this paper the development of the wood pellet production factors for markets in Germany, Sweden and Portugal are compared. Domestic market prices for pellet production factors as well as domestic market prices for pellets variation are analysed. The analysis are based on two model plants, representing the first common technologies for small scale production based on dry sawdust sources, and the second represents large scale production based on wet materials. The results show how differences in costs of raw materials, energy and labour affects wood pellets production. The economic sustainability for European pellet producers depends on their domestic markets as internationally traded pellets are priced lower than their production costs, being Portugal an exception due to lower labour and raw materials costs. Future pellet production will be based on wet raw materials such as logs and wet sawdust. These raw materials are also demanded by pulp and paper or fiberboard industries. The transition from smaller wood pellets plants using dry raw materials to larger plants using wet raw materials, can be expected to follow comparative advantages regarding raw materials, energy costs and economies of scale.

Biomass for energy production characteristics, amount and distribution in Latvia

Biomass is one of the largest renewable energy sources in Latvia. Since 54,7 % of the state area is covered by forests, the firewood, wood chips and pellets play a significant role in the heat production, especially at households and municipal heating facilities. Wood chips and pellets are also important export products. Changes in the energy-producing wood export since 1997 are explained. Other kinds of biomass that can be used for heat and electricity production are various agricultural and food production residues, livestock breeding buy-products, sewage sludge, combustible (organic) part of household and industrial wastes, etc. In the present paper, a variety of biomass forms used as the energy sources are analysed. The characteristics of different types of wood biomass and the variations in their parameters are considered. The following determined parameters of biomass are presented: the calorific value, ash content, bulk density, melting point of ashes, sulphur and chlorine content, and others. The biomass energy potential calculated for different regions of Latvia (the data of 2007) is discussed. On the map of Latvia the amount and energy potential of agricultural straw and other biomass for different regions are shown. Some recommendations elaborated how to improve biomass utilization for heat and electricity production.

Occupational Dust Exposure as a Risk Factor for Developing Lung Function Impairment.

Dust exposure is high in several industries. We investigated associations of exposure in paper mills, wood pellet plants, and iron foundries with lung function impairment. Respirable silica, inhalable paper dust, or inhalable wood dust were collected as personal samples and spirometry was performed. Multiple linear regression analyzed associations with FEV 1 %pred and FVC%pred. Wood pellet workers with high exposure to inhalable dust had lower FEV 1 %pred (95% CI) (-9.4 [-16 to -2.6]) and FVC%pred (-9.8 [-15 to -4.0]) compared with lowest exposure level. Workers at paper mills and foundries had no dose-dependent association but lower FEV 1 %pred and FVC%pred than in workers at wood pellets plants. Increased exposure to inhalable wood dust is associated with decreased lung function. Foundry and paper mill workers have generally lower lung function than wood pellet workers. Spirometry should be considered in workers in industries with airborne particulate matter pollution.