Impact of adhering soil and other extraneous impurities on the combustion and emission behavior of forest residue wood chips in an automatically stoked small-scale boiler

Zeng, Thomas; Kuptz, Daniel; Schreiber, Kathrin; Schön, Claudia; Schulmeyer, Fabian; Zelinski, Volker; Pollex, Annett; Borchert, Herbert; Loewen, Achim; Hartmann, Hans; Lenz, Volker; Nelles, Michael

doi:10.1007/s13399-018-00368-z

Cited by 18 publications

(14 citation statements)

References 82 publications

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“…In addition to horizontal screening, particle size distribution and particle shape were analysed using a continuously measuring image analysis device (Haver-CPA 4, Haver & Boecker GmbH, Germany) allowing for highly detailed information on the size and shape of the wood chips (Fig. 3 to 5) (Hartmann et al 2006, Hinterreiter et al 2012, Kuptz and Hartmann 2015, Kuptz and Hartmann 2021. The same samples were used for image analysis as for horizontal screening (n=1).…”

Section: Methodsmentioning

confidence: 99%

“…Due to the overall low amount of small particles of wood chips produced with the spiral chipper (see Section 3.2), these chips might incorporate a higher share of free cavities leading to a lower bulk density. A high porosity in bulk fuels might be useful for natural and artificial drying, as it decreases air pressure resistance during ventilation of wood chips ( Kristensen et al 2003, Kuptz and Hartmann 2021, Lenz et al 2015).…”

Section: Moisture Content and Bulk Densitymentioning

confidence: 99%

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Evaluation of Fuel Quality, Throughput Rate and Energy Consumption During Non-Industrial Wood Chip Production with Three PTO Driven Chippers

Kuptz

Hartmann

2021

Croat. j. for. eng. (Online)

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Physical wood chip quality is essential for failure-free and low emission combustion in small-scale boilers ≤100 kW. In Bavaria, these furnaces are often operated by farmers or private forest owners that produce their own fuels using small to medium sized PTO-driven chippers. As secondary fuel processing steps such as industrial screening are usually too expensive for private forest owners, the selection of suitable raw materials and process parameters to directly produce high quality fuels during chipping are deemed especially relevant for this user group. In the present study, three commonly used small-scale chippers ≤150 kW, i. e. a drum, a spiral and a disc chipper where evaluated in terms of fuel quality, throughput rate and energy consumption during wood chip production. Chipping was done using stem wood of European beech and Norway spruce. Machine settings were the ones recommended by the chipper manufactures for the production of high quality fuels. Additional chipping variants included the use of different raw materials such as crown residues of European willow and varying machine settings including blunt knives, increasing spiral cut length, large screen mesh sizes or increased PTO speeds. Representive wood chip samples were taken after each trial and analysed in their physical fuel properties according to international standards for solid biofuels but also using a continuously measuring image analysis device to determine particle length and particle shape. For all three mobile chippers, wood chips with the particle size class »P31s« according to the revised ISO 17225-4:2021 could be produced when stem wood was used as assortment. Fine content of chips, i. e. particles ≤3.15 mm, was lowest for the spiral chipper and increased for the drum and disc chipper, especially when blunt knives or narrow screen meshes were used for chipping. At the same time, blunt knives increased the particle shape factor (PSF) of the bulk materials indicating a rather broken particle surface structure compared to clean cut particles. Throughput rate decreased and energy consumption increased when fuels with small particle size were produced, e. g. when narrow screen meshes or narrow chipping spirals were applied. This trend was particularly pronounced when blunt knives were used for chipping due to grinding of the material. All three chippers could be recommended for the production of high quality fuels for small-scale boilers when suitable machine settings and raw materials are applied for chipping.

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Section: Methodsmentioning

confidence: 99%

Section: Moisture Content and Bulk Densitymentioning

confidence: 99%

Evaluation of Fuel Quality, Throughput Rate and Energy Consumption During Non-Industrial Wood Chip Production with Three PTO Driven Chippers

Kuptz

Hartmann

2021

Croat. j. for. eng. (Online)

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“…The largest increase in time horizons was achieved by the combustion of wood chips (Khattak et al 2020). It should be noted that wood chips release greenhouse gases during combustion, especially CO2, and thus releases the carbon sequestered by the growth of wood into the air (Zeng et al 2019). Nonetheless, its substitution for other fossil fuels with a higher carbon content ultimately reduces the production of greenhouse gases (Hájek et al 2019).…”

Section: Renewable Energy Consumptionmentioning

confidence: 99%

An analysis of renewable energy consumption efficiency in terms of greenhouse gas production in selected European countries

Rozenský

Hájek

Vrba

et al. 2020

BioRes

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The consumption of renewable energy sources results in the minimal production of greenhouse gases. However, the issue of environmentally efficient use of renewable energy sources remains a key concern. The primary aim of this article was to assess whether the energy production from renewable energy sources was environmentally efficient in four selected European countries: Germany, Austria, Poland, and the Czech Republic. In order to achieve the primary research goal, a regression analysis method was used for several variables. The results of the analysis suggested that with an increase in the consumption rate of renewable energy sources and biofuels equivalent to one thousand tons of oil, the volume of emissions from all sectors would increase by 0.0048 thousand tons (4.8 tons) on average. The system of emission allowances was rather environmentally inefficient at the lower allowance levels; in the monitored period of 2007 to 2016, the dependence of greenhouse gas production on the consumption of fossil fuels did not statistically manifest itself. Based on the analysis, the land use, land-use change, and forestry production activities do not contribute to increasing total greenhouse gas emissions.

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“…To achieve the required moisture, natural drying [18,19] or technical drying [20][21][22][23][24][25][26][27] can be used. Screening is employed to improve the particle size distribution after chipping and to reduce ash-related problems [9,28,29]. However, elaborate pretreatment increases the energy demand during fuel production and requires additional storage space and extra manpower for operation and maintenance [30].…”

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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Impact of adhering soil and other extraneous impurities on the combustion and emission behavior of forest residue wood chips in an automatically stoked small-scale boiler

Cited by 18 publications

References 82 publications

Evaluation of Fuel Quality, Throughput Rate and Energy Consumption During Non-Industrial Wood Chip Production with Three PTO Driven Chippers

Evaluation of Fuel Quality, Throughput Rate and Energy Consumption During Non-Industrial Wood Chip Production with Three PTO Driven Chippers

An analysis of renewable energy consumption efficiency in terms of greenhouse gas production in selected European countries

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

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