Influence of wood chip quality on emission behaviour in small-scale wood chip boilers

Schön, Claudia; Kuptz, Daniel; Mack, Robert; Zelinski, Volker; Loewen, Achim; Hartmann, Hans

doi:10.1007/s13399-017-0249-7

Cited by 29 publications

(11 citation statements)

References 16 publications

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“…Standards are designed in a way that enables the standardization of different solid biofuels including densified solid biofuels (pellets and briquettes) and thermally treated biofuels (charcoal), but also minimally processed fuelwood (firewood, hog fuel, and wood chips). Due to an increasing industrial scale use of wood chips for production of heat and electricity, it is important to acknowledge that wood chips quality is the major factor in energy production efficiency [10], and that the quality of wood chips is important for proper functioning of small scale non-industrial appliances [11,12]. Therefore, the standard that defines general requirements, in terms of fuel specification and classes-HRN EN ISO 17225-1:2014 [13] points out dimensions, moisture content, and ash content as the main normative properties of wood chips.…”

Section: Introductionmentioning

confidence: 99%

Variability of Normative Properties of Wood Chips and Implications to Quality Control

et al. 2021

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The research was conducted with the goal to determine the variability of the quality parameters of the wood chips produced from the most favorable raw material (energy roundwood), and in the most controllable operational conditions (pellet factory), as the first step in identifying opportunities to optimize the wood chips’ quality monitoring. Four raw material types were tested: fir/spruce and beech debarked energy roundwood, as well as energy wood with bark of the same species. Sampling was conducted during six consecutive months along with laboratory testing, all according to the HRN EN ISO standards for solid biofuels. Interpretation of the results was done in relation to deviation from the first sampling results (as an indicator of the possibility to retain the quality of wood chips), and repeatability and reproducibility set in the standards (as an indicator of acceptable variability). The influence of the species and debarking process on the wood chips’ quality was analyzed as well. Relative deviation from the first sampling as well as the quality class change pointed moisture content as a normative property with the lowest possibility to retain initial values over the six-month period. Ash content results indicated a strong possibility to maintain the initial ash content class in the majority of the samples. In just three cases, the results of ash content were outside the reproducibility limits with first sampling as a reference. Gross calorific value results pointed only four samples outside the reproducibility limits with the first sampling results are set as a reference. Wood species influenced gross calorific value and the median value of the particle size distribution and debarking showed a significant positive effect on the moisture content reduction as well as on the ash content reduction. Presented findings are indicative for the investigated raw materials, however for the general conclusion on the subject of wood chips normative properties variation, various raw material types will have to be examined in further research.

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Section: Introductionmentioning

confidence: 99%

Variability of Normative Properties of Wood Chips and Implications to Quality Control

et al. 2021

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“…Solid biomass combustion plants-from kilowatt-sized furnaces for domestic heating to combined heat and power plants in the megawatt range-suffer from a decisive drawback in comparison to many other (mainly fossil) alternatives due to the low quality and the challenging properties of the utilized feedstock. Inappropriate fuel quality drastically affects a biomass furnace's behavior: Subpar biomass reduces the lifespan of a furnace and leads to operational challenges, such as corrosion, ash deposition [1][2][3][4][5] as well as increased gaseous and particulate emissions [6]. The majority of industrial solid biomass combustion plants rely on woody biomass (commonly known as wood chips) as feedstock.…”

Section: Introductionmentioning

confidence: 99%

Image-Based Model for Assessment of Wood Chip Quality and Mixture Ratios

Plankenbühler

Kolb

Grümer³

et al. 2020

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This article focuses on fuel quality in biomass power plants and describes an online prediction method based on image analysis and regression modeling. The main goal is to determine the mixture fraction from blends of two wood chip species with different qualities and properties. Starting from images of both fuels and different mixtures, we used two different approaches to deduce feature vectors. The first one relied on integral brightness values while the latter used spatial texture information. The features were used as input data for linear and non-linear regression models in nine training classes. This permitted the subsequent prediction of mixture ratios from prior unknown similar images. We extensively discuss the influence of model and image selection, parametrization, the application of boosting algorithms and training strategies. We obtained models featuring predictive accuracies of R2 > 0.9 for the brightness-based model and R2 > 0.8 for the texture based one during the validation tests. Even when reducing the data used for model training down to two or three mixture classes—which could be necessary or beneficial for the industrial application of our approach—sampling rates of n < 5 were sufficient in order to obtain significant predictions.

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“…However, due to the growing competition for high‐quality wood assortments , , low‐quality wood assortments like forest residues, wood chips from roadside maintenance, or scrap wood shall be increasingly used. These materials are commonly characterized by higher amounts of fines and ash‐forming matter in addition to a disadvantageous particle size distribution . Thus, mechanical fuel pretreatment is usually a prerequisite for the use of these assortments.…”

Section: Introductionmentioning

confidence: 99%

Influence of Screening and Drying on Low‐Quality Wood Chips for Application in Small‐Scale Gasification Plants

et al. 2020

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Before using low-quality wood chips for gasification on the small and medium scale (30-500 kW el), mechanical fuel pretreatment has to be employed to ensure the required fuel characteristics concerning particle size distribution and moisture. Two different low-quality wood assortments (calamity wood and roadside maintenance wood) were subjected to three different mechanical fuel pretreatment strategies and a detailed analysis was realized along the supply chains. The results reveal the enrichment in elements characteristic of soil contamination in the removed fine fraction. Gasification tests were successfully performed with the upgraded low-quality fuels in field trials and indicated comparable electrical efficiencies but higher supervision effort during plant operation.

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Influence of wood chip quality on emission behaviour in small-scale wood chip boilers

Cited by 29 publications

References 16 publications

Variability of Normative Properties of Wood Chips and Implications to Quality Control

Variability of Normative Properties of Wood Chips and Implications to Quality Control

Image-Based Model for Assessment of Wood Chip Quality and Mixture Ratios

Influence of Screening and Drying on Low‐Quality Wood Chips for Application in Small‐Scale Gasification Plants

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