Wood Pellet Quality Research Articles

Reducing the Ash Content of Gliricidia (Gliricidia sepium) and Calliandra (Calliandra calothyrsus) Wood Pellets through Debarking and Mixing with Acacia (Acacia mangium) and Pines (Pinus merkusii) Wood

The use of renewable energy from wood biomass which is processed in the form of wood pellet are environmentally friendly, sustainable and also to reduce greenhouse effect and environmental pollution. The main problem in the quality of a wood pellet from Gliricidia and Calliandra is the ash content (1%) has not fulfilled the Europe quality standard requirement A1-EN14961 (ash content ≤ 0.7%) yet fulfills the A2-EN14961 quality standard. The effort to lower the ash content is by debarking and mixing with other wood variety to increase the quality of Gliricidia and Calliandra wood pellet quality in the international market. The aim of this research is to discover the effect of debarking and mixing of Gliricidia and Calliandra with pine and acacia wood toward the quality of wood pellet, especially the ash content. The result shows ash content for pine wood pellet and acacia wood pellet consecutively 0.36% and 0.71% have fulfilled the Europe quality standard EN 14961 (max. 0.7%) and have the potency to be the mixer raw material for Gliricidia (ash content 1.19%) and Calliandra (ash content 1.05%). Debarking method can lower the ash content of Gliricidia and Calliandra wood pellet consecutively 36.1% (from 1.19% to 0.76%) and 18.1% (from 1.05% to 0.86%) and almost fulfill the A1 Europe quality standard (EN 14961 max 0.7%). Wood mixing Gliricidia-Calliandra-Pine (1:1:1) ash content is 0.89% with 20.5% decreasing rate, almost fulfill the A1 Europe quality standard (EN 14961 max 0.7%). Wood mixing Gliricidia-Calliandra-Acacia (1:1:1) ash content is 1.17% with 2.7% decreasing rate. Method combination by mixing pine wood, debarking of gliricidia and calliandra have the potency to generate wood pellet with ash content suitable with the A1 Europe standard EN 14961 max 0.7% [1].

Karakteristik Pelet Serbuk Gergaji Tiga Jenis Kayu Limbah Industri Mebel Sebagai Energi Alternatif Terbarukan

Wood industry waste in Indonesia is very abundant, the percentage based on yield produced can reach 50% for sawdust, 70% for plywood industry waste, and 70% of forest harvesting waste. Wood pellets can be an alternative energy source and the availability of raw materials is very easy to find. Wood pellets are the main concern at this time because of the ease of use in raw materials and have environmentally friendly characteristics. The aims of this research was to investigate the characteristic of wood pellets from three types sawdust of wood waste from furniture industry on Palangkaraya city and compare the propreties of wood pellet with Indonesian National Standard (SNI 8021: 2018). This study used material from the sawdust waste of benuas (Shorea laevis Ridl), melur (Dacrydium spp), and jelutung rawa (Dyera polyphylla). Particles from those materials were made on 40-60 mesh, and to reduce the of extractive substances, the particles were extracted in hot water at 100°C for 3 hour. Pellets are made using single-pelletizer at room temperature with a pressure of 30 MPa for 4 hour. The target density of wood pellet was 1 g/cm³ with a diameter was 0.9 cm and length weas 4.5 cm. The results showed that the quality of Benuas, Melur and Jelutung Rawa wood pellets based on SNI 8021: 2018 wood pellet quality standards showed that the testing of wood pellets in general met the Indonesian National Standards except density. Based on the characteristics of the three types of sawdust waste studied based on specific gravity that the type of wood pulp with medium density as raw material for wood pellets that have the best quality because it has a lower water content of 3.72%, higher density 0.75 g / cm3, lower ash content 0.6%.

Study on the effects of storage conditions on pretreated and raw biomass

This study aims to investigate influential of the storage condition that affects biomass properties that are covering storages (covered and uncovered) of the torrefied and untorrefied pellets of wood and corncob pellets. And the properties of the pellet after storage for 6 months consist of higher heating value (HHV), moisture content, durability, and dry matter loss. The result shows that the torrefied (wood and corncob) pellets have higher HHV than untorrefied pellets around 15-30%. For the moisture content, the covered pellets have less moisture content than uncovered approximately 3% for both (wood and corncob pellets). Furthermore, the durability continuously decreases from start to 6 months until the durability of corncob black wood and corncob pellet decrease around 95.2% in the case uncovered while in the covered case of wood and corncob, the durability decline around 7.4% and 4.1% respectively. To sum up, the experiment demonstrates that piling a pellet under dry conditions (or covering the pellet to avoid moisture conditions) can upgrade the HHV and energy density of the pellet and the quality of torrefied pellet is greater than untorrefied pellet as well as the wood pellet quality is also better than corncob in term of a low increasing rate of moisture content and dry matter loss and higher of durability, HHV and energy density.

POTENSI TUMBUHAN PIONIR UNTUK WOOD PELLET SEBAGAI BIOENERGI TERBARUKAN

The increasing demand for energy in Indonesia is due to the need or the number of Indonesian population which has increased and is inversely proportional to the availability and production of existing energy. One of the best solutions that can be done is to promote the use of pioneer wood (fast growing plant) as an energy source by processing wood into wood pellets. The method used is a survey method by looking for a place to grow several types of pioneer plants. The purpose of this study was to determine the quality of wood pellets and the potential of several types of pioneer plants tested as environmentally friendly, sustainable renewable bioenergy. The pioneers tested were Acacia mangium, Jatropha curcas, Macaranga tanarius, Swietenia mahagoni, Leucaena leucocephala, and Sesbania grandiflora. The quality of Wood Pellets from pioneer plants is seen from the density ranging from 0.433 gr / cm3 to 0.503 gr / cm3, moisture content of 5.55% - 12.4%, ash content of 1.95-6.2%, and the calorific value of powder from 3657.67% - 4178.18%. Of the several types of pioneer plants tested, the most potential was Leucaena leucocephala because it had met SNI 8021 - 2014 and had the highest calorific value as required.

Photomicrogrph Atlas of Wood Pellet Components

Concerns about climate change, energy security, and the diversification of energy supplies have made renewable resources increasingly more attractive and important sources of energy. As interest grows, bioenergy (energy from bio-based sources) is becoming more environmentally friendly and economically viable and has started to play a more prominent role in the global energy mix. In this changing market, wood pellets have emerged as a sustainable source of power with the potential to become a mainstream fuel in the future energy market. Pellets are currently the most economical way of converting biomass into fuel, and they are a fast-growing component of the energy sector. Pellets can be made from various types of biomass including industrial waste and co-products, food waste, agricultural residues, and virgin lumber, which are compressed under high pressure. Among these, wood pellets are the most common, and they generally are made from raw trees, wood shavings, compacted sawdust, industrial wastes from the milling of lumber, manufacture of wood products and furniture, and construction. The wood pellets available on the market are sold as fuel (heating and grilling) or as absorbents for animal bedding. But while the wood pellets are a fast-growing component of the energy sector and important tool in fight with global warming, it is important to understand influence of wood pellet quality on combustion emissions, and how their usage impacts human health and environment. Thanks to wood pellet industry efforts, especially in the North America and European Union, many of the wood pellets follow rigorous production procedures, and certification. However, there are still some manufacturers that do not use the same production scrutiny, which can result in poorer quality of their pellets. Our research show that in some extreme cases these uncertified wood pellets contain more than 20 percent of impurities. While some of those contaminants are so big that can be visible even without microscope the majority of the contaminants are of micrometer size and can be detected and identify only under a microscope. While the current standards test the quality of pellets based on a variety of physical and chemical properties, some impurities in pellets (glass, plastic, metal, ceramics, coal, and coke) are not easily identified this way. Our research shows that reflected light microscopy can be successfully used to identify and quantify those contaminants. Although reflected light microscopy technique is a well-known and widely used method allowing examination of various materials, this is a novel application for pellet fuels.

Evaluation of Bioenergy Potential and Relative Impact of Microclimate Conditions for Sustainable Fuel Pellets Production and Carbon Sequestration of Short-Rotation Forestry (Populus × Canadensis Moench.) in Reclaimed Land, South Korea: Three-Year Monitoring

It is important to manage sustainable short-rotation coppices (SRCs), having an important role in carbon sink and bioenergy output, because most of SRCs in South Korea were established on reclaimed land. However, during the last three years, the growth pattern of the SRCs was remarkably changed with soil condition. This study aimed to identify the sustainability of SRCs used for carbon storage, biomass and fuel pellet production, monitoring the neighboring vegetation of SRCs by land-use exchange, examine physiological changes of poplar in a seasonal trend, and to evaluate whether poplar is suitable for making wood pellets over time. The calculated biomass yield per area of poplar grown was 103.07 Mg per total area (55.6 ha), and volumes of carbon dioxide absorption were estimated to be 329.72 Mg CO2. Wood pellet quality based on the criteria scored third grade, indicating that poplar is appropriate to be manufactured as fuel pellets. Moreover, monitoring of the flora distribution in SRCs revealed changes in species composition. As halophyte was increased during drought, soil organic matter, net growth and total chlorophyll of poplar were significantly decreased. These findings indicate that physiological changes and growth pattern of SRCs may be negatively affected by microclimate and provide better understanding for the effective management of SRCs amid environmental changes.

The Wood Pellet Sector: Barriers to Growth and Opinions of Manufacturers in Poland

Biomass is a major source of renewable energy in the EU and Poland, stimulating the growth of the wood pellet sector. Wood pellet demand is stimulated by a complex interaction of market forces and policies including EU climate, energy, and environmental regulations, Poland’s program to improve air quality, and subsidies for the replacement of inefficient stoves used by households. This article focuses on the growth of the wood pellet industry, imports and exports in Poland, and wood pellet quality and use by households. The main issues faced by the EU wood pellet sector between 2013 and 2016 are further considered in the context of opinions of Polish wood pellet manufacturers. Industry opinions were collected in response to an open-ended question that probed for the main issues faced by wood pellet producers during the survey implemented by the authors in 2019. Respondents identified difficulties in obtaining raw material for pellet production and poor pellet quality as major problems. Although the majority did not feel concerned about competition from imported wood pellets, a small number of respondents viewed such competition as a problem reflecting the reversal of decreasing imports in 2017. Overall, the domestic wood pellet industry can be expected to grow because of increasing pressure to expand the use of renewable energy and will be driven by the household sector switching to more efficient, wood burning stoves. Additionally, the expanding area of private Polish forests may become a source of much-needed raw material for wood pellet manufacturing.

Optimizing Quality of Wood Pellets Made of Hardwood Processing Residues

Small-scale wood pellet producers often use a trial-and-error approach for determining adequate blending of available wood processing residues and pelletizing parameters. Developing general guidelines for optimizing wood pellet quality and meeting market standards would facilitate their market entry and profitability. Four types of hardwood residues, including green wood chips, dry shavings, and solid and engineered wood sawdust, were investigated to determine the optimum blends of feedstocks and pelletizing conditions to produce pellets with low friction force, high density and high mechanical strength. The feedstock properties reported in this study included particle size distribution, wood moisture content, bulk density, ash content, calorific values, hemicelluloses, lignin, cellulose, extractives, ash major and minor elements, and carbon, nitrogen, and sulfur. All residues tested could potentially be used for wood pellet production. However, high concentrations of metals, such as aluminum, could restrict their use for accessing markets for high-quality pellets. Feedstock moisture content and composition (controlled by the proportions of the various residue sources within blends) were the most important parameters that determined pellet quality, with pelletizing process parameters having less overall influence. Residue blends with a moisture content of 9%–13.5% (dry basis), composed of 25%–50% of sawdust generated by sawing of wood pieces and a portion of green chips generated by trimming of green wood, when combined with a compressive force of 2000 N or more during pelletizing, provided optimum results in terms of minimizing friction and increasing pellet density and mechanical strength. Developing formal relationships between the type of process that generates residues, the properties of residues hence generated, and the quality of wood pellets can contribute to optimize pellet production methods.

Jakość pelletu drzewnego stosowanego w automatycznych kotłach klasy 5 z Ecodesign na rynku detalicznym w kontekście ochrony powietrza w Polsce

Jakość pelletu drzewnego stosowanego w automatycznych kotłach klasy 5 z Ecodesign na rynku detalicznym w kontekście ochrony powietrza w Polsce

Influence of blending and hot water extraction on the quality of wood pellets

In order to meet the projected demand for biomass feedstocks, multiple sources will be needed. Biomass feedstocks are often have a high degree of variability with regards to important properties such as ash, moisture, and energy content. The efficiency of conversion processes may be sensitive to this variability; thus, strategies are needed to ensure that consistent and reliable feedstocks are produced that meet end-user specifications. The objective of this study was to examine the effect of source, blending and hot water extraction (HWE) on the quality of wood pellets. Debarked maple biomass was blended at various rates with whole stem harvested willow, HWE willow, and HWE maple biomass, made into pellets and then compared to existing ISO (17225) pellet standards. Untreated willow pellets were unable to consistently meet key specifications such as ash and moisture. However, pellets blended with either HWE willow, maple or HWE maple at rates between 20 and 50 percent willow still met the most stringent requirements. HWE decreased the ash content of willow below 1% and was on par with untreated maple. HWE increased the energy content of pellets in this study approximately 1 MJ kg−1. Blending and HWE have the potential to decrease variation in feedstock for pellet production and expand the range of material that can be used while still meeting standards for quality. Technologies for rapidly assessing feedstock properties at the front or back end will be needed to maximize the benefits of these two strategies when more variable feedstocks are used.

Effects of increased soil fertility and plant growth-promoting rhizobacteria inoculation on biomass yield, energy value, and physiological response of poplar in short-rotation coppices in a reclaimed tideland: A case study in the Saemangeum area of Korea

This study aims to investigate the physiological response, biomass yield and its bio-energy value to charcoal mineral fertilizer and Bacillus subtilis strain JS, a plant growth-promoting rhizobacteria, under nine different soil-enrichment procedures, and to provide a reference for suitable management strategies for short-rotation coppices on the marginal soils of reclaimed tidelands in Saemangeum area of Korea. The treatments used in this experiment were as follows: 1) 1:100 (volume basis) diluted rhizobacteria inoculation {B1, (B. subtilis: double-distilled water, v/v)}, 2) 1:50 diluted rhizobacteria inoculation (B2), 3) mineral fertilization {F1, (charcoal 200 kg ha−1)}, 4) additional mineral fertilization {F2, (charcoal 300 kg ha−1)}, 5) F1+B1, 6) F2+B1, 7) F1+B2, 8) F2+B2, and 9) control plot with no soil enrichment (C). The plant species used in this study is Populus euramericana. Net photosynthetic assimilation using leaves acclimated for 2 min at 1500 μmol m−2 s−1 was the highest in F1+B2, followed by B2+F2 and B2. Total biomass yield in F2+B2 was the highest by a significant margin among the nine soil-enrichment procedures, whereas that in the control soil was lowest. Plants in all soil conditions provided similar net calorific values of dry mass, and they all fell within the third grade of wood pellet quality criteria of the National Institute of Forest Science standard specification (Korea), within the premium category in the Pellet Fuels Institute standard specification (US), and within the A1 category in the EN-Plus standard specification (EU). Moreover, it was confirmed that the poplar was suited to produce wood pellets for heating energy.

Characterization and elemental analysis of wood pellets obtained from low-valued types of wood

ABSTRACTIn this study, we compared the quality of wood pellets obtained from several different raw materials, i.e., Rhododendron ponticum (Type 1), Laurus nobilis (Type 2), and Castanea sativa (Type 3). The quality of the wood pellets was characterized mainly by their bulk density, moisture content, ash content, volatiles, sulfur content in the ash, total sulfur content, heating values, elemental analysis of the ash, and chlorine content. The results showed that bulk density was similar for each type of pellet. In quality values, ash content and the sulfur content in the ash were found to be lower for Type 3 (Chestnut wood pellets) than they were for the other two types. The results also showed that dry samples of Type 1, Type 2, and Type 3 wood pellets had heating values of 5057, 4691, and 4571 kcal/kg, respectively, whereas the original (undried) samples had heating values of 4571, 4409, and 4293 kcal/kg, respectively.

Specific energy consumption and quality of wood pellets produced using high-moisture lodgepole pine grind in a flat die pellet mill

In the present study a Box–Behnken experimental design was used to understand the effect of the moisture content of lodgepole pine grind (33–39%, w.b.), die speed (40–60Hz) and preheating temperature (30–90°C) on the pellet quality and specific energy consumption. The partially dried pellets produced had high-moisture content in the range of 19–28% (w.b.), and were further dried to <9% (w.b.) in a mechanical oven set at 70°C for 3h. Dried pellets were further evaluated for pellet moisture content, unit, bulk, tapped density, and durability. Response surface models developed for the product properties have adequately described the process based on coefficient of determination values. Surface plots developed indicated higher unit, bulk, and tapped density (1050, 520, 560kg/m3) are achievable at 33–35% (w.b.) moisture content of the lodgepole pine grind, die speed of 60Hz and preheating temperature of 30–60°C. Higher moisture content of 39% (w.b) reduced unit, bulk, and tapped density to <912, 396, and 452kg/m3. Higher durability values of >95% were obtained at 33–35% (w.b.) at lower preheating temperatures of 30–50°C and higher die speed of >50Hz. At 33% (w.b.) moisture content of the lodgepole pine grind, preheating temperature of 90°C, and die speed of 60Hz, the observed specific energy consumption was <116kWh/ton. Scanning electron microscope studies indicated that lignin crosslinking is the primary reason for binding of the lodgepole pine grind at high-moisture content.

Can woody biomass support a pellet industry in southeastern Ontario: A case study

The European Renewable Energy Directive introduced in 2009 mandates a 20% renewable energy share by 2020 and has driven a rising trend of wood pellet usage in EU member states that exceeds the domestic supply. This surge presents an exporting opportunity for pellet manufacturers in North America. In recent years Canada has supplied the bulk of its wood pellets to Europe; this is changing as western Canadian producers shift their focus to Asian markets. With this development and with a new dedicated pellet shipping port in Quebec, eastern Canada is well placed to increase the supply of pellets to Europe. The potential for a pellet industry in Bancroft, Ontario was evaluated by quantifying sawmill residues from twelve mills within a 200-km radius. Given recent downturns in the lumber industry, a pellet mill in Bancroft would deliver economic benefits to the local community. Using a sawmill residue model and forest biomass characterization database, these residues were evaluated to determine the potential output and quality of wood pellets. Standing trees in the region currently allocated as pulpwood were also analyzed as a potential source of biomass. The analysis of biomass resources in the Bancroft region illustrates the potential for a pellet industry meeting European pellet standards with a minimum annual production of 100 000 tonnes.

The effects of storage on the net calorific value of wood pellets.

The wood pellet export from Canada to Europe has been increasing steadily in recent years (roughly 1.8 million ton in 2013). Due to distances involved, wood pellets remain in transit and storage for months before their final consumption. The net calorific value determines the price of wood pellet purchase in Europe. There have been concerns about the changes of net calorific values over time. In this study, the effects of storage time, storage configuration, storage temperature, and wood pellet quality on the net calorific value of wood pellets for a period of 6 months were investigated. Storage configurations were open or closed and storage temperatures were 25 °C, 35 °C and 45 °C. Two types of wood pellets used were whitewood and mixed. The results in closed storage indicated that storage time had a positive effect on the net calorific value where the net calorific value increased by 1% to 2% over the storage period. In open storage, the moisture content had the most significant impact on the net calorific value. The net calorific values of the two types of wood pellets were found to be significantly different at p < 0.001. A multivariable linear regression and analyses of variancemore » performed verified the graphical results. Lastly, the authors postulated that the higher energy potential compounds, such as aldehyde and ketone, produced during pellet storage, caused the increase in net calorific values.« less

Impact of fuel quality and burner capacity on the performance of wood pellet stove

Pellet stoves may play an important role in Serbia in the future when fossil fuel fired conventional heating appliances are replaced by more efficient and environmentally friendly devices. Experimental investigation was conducted in order to examine the influence of wood pellet quality, as well as burner capacity (6, 8 and 10 kW), used in the same stove configuration, on the performance of pellet stove with declared nameplate capacity of 8 kW. The results obtained showed that in case of nominal load and combustion of pellets recommended by the stove manufacturer, stove efficiency of 80.03% was achieved. The use of lower quality pellet caused additional 1.13 kW reduction in heat output in case of nominal load and 0.63 kW in case of reduced load. This was attributed to less favourable properties and lower bulk and particle density of lower quality pellet. The use of different burner capacity has shown to have little effect on heat output and efficiency of the stove when pre-set values in the control system of the stove were not altered. It is concluded that replacement of the burner only is not sufficient to increase/decrease the declared capacity of the same stove configuration, meaning that additional measures are necessary. These measures include a new set up of the stove control system, which needs to be properly adjusted for each alteration in stove configuration. Without the adjustment mentioned, declared capacity of the stove cannot be altered, while its CO emission shall be considerably increased.

Fuel Properties of Woody Pellets in Domestic Markets of Korea

This study investigated physical properties and combustion gas characteristics for 8 types of wood pellets (4 domestic and 4 imported products) distributed in the domestic market. Results showed that most pellet types were first-grade pellets in the wood pellet quality standards in Korea with the exception of 3 pellet types from K company (second-grade in mechanical durability), G company (off-grade in nitrogen content) and P company (second-grade in ash percentage). Mixed pellets which contained more lignin and sap content were higher in mechanical durability (%) than that of white pellets. From the combustion gas analysis results, NOx emitted from all pellets combustion was at acceptable levels for national emission standard of the Clean Air Conservation Act except for pellets from G company. In addition, CO levels from all types of wood pellets were acceptable except for pellets from D company and domestic pellets were higher CO levels than imported pellets. These results indicate the higher CO levels in domestic pellets due to the usage of forest thinning materials including logging debris which usually had the high content of bark.

A multivariate SIMCA index as discriminant in wood pellet quality assessment

The pellet market has experienced a continuous development and increase in recent years due to a number of positive properties of this enhanced biomass. However the supply chain has not been entirely able to follow the same trend, causing some issues, often related to the quality of traded products. These problems can be partially solved by ensuring a continuous and reliable flow of information regarding the quality parameters of wood pellets from the producers to the final users. The aim of this work is to define a metric index for quality parameters that can detect the certifiability of analyzed samples compared with those on the market. The model is built on measured quality parameters of certified and non-certified wood pellet samples taken from products on the market applying a multivariate class modelling methodology (soft independent modelling of class analogy, SIMCA). Results showed that the model can predict the general quality of some test samples and that its precision, already fairly high, can be constantly improved by adding new model samples. The output of the model is also the relative influence (modelling power) of each variable in the prediction of certifiability. The SIMCA model could be easily integrated and implemented on the most common digital platforms where users (private, laboratories, agencies, etc.) could test their samples and verify if the index of their pellet falls within the area defined by the model for certified samples.

Effects of thermal treatment on energy density and hardness of torrefied wood pellets

Three types of wood pellets samples, including two types of commercial pellets and one type of lab-made control pellets were torrefied in a fixed bed unit to study the effect of thermal pretreatment on the quality of wood pellets. The quality of wood pellets was mainly characterized by the pellet density, bulk density, higher heating value, Meyer hardness, saturated moisture uptake, volumetric energy density, and energy yield. Results showed that torrefaction significantly decreased the pellet density, hardness, volumetric energy density, and energy yield. The higher heating value increased and the saturated moisture content decreased after torrefaction. In view of the lower density, lower hardness, lower volumetric energy density, and energy yield of torrefied pellets, it is recommended that biomass should be torrefied and then compressed to make strong pellets of high hydrophobicity and volumetric energy density.

Wood pellet quality with respect to EN 14961-2 standard and certifications

Wood pellet production has increased hugely in recent years from 7 to 19 milliontons in the period 2006–2012, mainly due to the demand created by policies and bioenergy use targets in Europe. Italy is one of the most important importers for domestic heating application and the Italian market can be considered a good subject to estimate the efficacy of quality standards and certification application. The assessment of the quality of wood pellet sold in the market and how the information reported on bag reflect the quality of the product has been carried out during a three-year period. Characterisation analyses and collection of data regarding information reported on bags such as characterisation results, ash class, wood species, certifications, and standard references have been carried out. Results have been statistically evaluated. More than half of samples fulfill the requirements of the A1 class of EN 14961-2 standard, related to the higher quality pellets. Certification, like ENplus and DINplus, appears to be appropriated to guarantee for a high quality of pellet sold in the market. Ash content alone could be a good representative parameter for a first, rapid quality assessment. Ash content results significantly lower in coniferous pellet than in broadleaf one.