• Geomechanics and Engineering
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• v.38 no.4
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• pp.335-352
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• 2024

Low carbon energy demand in South Korea is increasing, hence leading to an increasing usage of wood pellets and the amount of its combustion by-product called wood pellet fly ash (WA). In an effort to develop recycling technology, this research investigates the use of WA as a new sustainable binder for backfill soil materials. The influence of WA on weathered granite soils (WS) is investigated by mixing 5%, 15%, and 25% of WA dosage, compacted at optimum moisture content, then cured for 3, 7, 14, and 28 days. After curing, the compacted specimens were investigated through unconfined compressive tests, pH tests, total suction tests, and microstructural analysis. The findings suggest that the higher the dosage rate, the higher strength and modulus. Additionally, the alkali ions of WA aid in the cementation of WS particles, and newly cementitious minerals are confirmed after 28 curing days. The refinement of pore microstructures led to a denser WS matrix and stiffness improvements. The results validate the binding potential of wood pellet fly ash on weathered granite soils in terms of strength, modulus, and microstructures.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.4
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• pp.83-90
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• 2019

In this study, the characteristics of the SRF (Solid Refuse Fuel) prepared by blending each of the additives (citrus peel, waste wood, coal) in the heavy oil fly ash, evaluating the heavy oil fly ash recyclability. Recycling SRFs were fabricated by pellet extruding method after blending the heavy oil fly ash and additives based on 30% moisture content. As a result, the formability of the SRFs was excellent under condition of blending heavy oil fly ash with coal or citrus peel and the highest calorific value was 4,274 kcal/kg at heavy oil fly ash mixed with coal. Therefore, the formability and calorific value were improved when the heavy oil fly ash was mixed with coal(20 wt%) at 30% moisture content. From these results, the applicability of SRFs with additives was confirmed by using the heavy oil fly ash from J thermal power plant.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.77-78
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• 2023

This paper experimentally examined the recycling of combustion by-products emitted from a combined heat and power plant using lignocellulosic biomass fuel. Physical and chemical analyzes were performed on Bio-SRF and three types of wood pellet combustion by-product samples (fly-ash, FA). As a result of the experiment, the compressive strength of mortar substituted with 5, 10, and 20% of FA compared to the cement weight was found to be excellent, and its recyclability was confirmed as a substitute for existing admixtures.

• Clean Technology
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• v.24 no.4
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• pp.323-331
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• 2018

The results of an experimental investigation on the co-firing characteristics and slagging behavior of dried and hydrothermal carbonization sewage sludge, sub-bituminous coal, and wood pellet in a fluidized bed were presented. Combustion tests were conducted in a lab-scale bubbling fluidized bed system at the uniform fuel-air equivalence ratio, air flow rate, and initial bed temperature to measure bed temperature distribution and combustion gas composition. 4 different fuel blending cases were prepared by mixing sewage sludge fuels with coal and wood pellet with the ratio of 50 : 50 by the heating value. $NO_x$ was mostly NO than $NO_2$ and measured in the range of 400 to 600 ppm in all cases. $SO_2$ was considered to be affected mostly by the sulfur content of the sewage sludge fuels. The cases of hydrothermal carbonization sewage sludge mixture showed slightly less $SO_2$ emission but higher fuel-N conversion than the dried sewage sludge mixing cases. The result of fly ash composition analysis implied that the sewage sludge fuels would increase the possibility of slagging/fouling considering the contents of alkali species, such as Na, K, P. Between the two different sewage sludge fuels, dried sewage sludge fuel was expected to have the more severe impact on slagging/fouling behavior than hydrothermal carbonization sewage sludge fuel.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.663-671
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• 2023

This research experimentally evaluated the recyclability of four varieties of lignocellulosic fly ash(FA), a by-product from three power plants employing lignocellulosic biomass(Bio-SRF, wood pellets) as a fuel source. Comprehensive analyses were conducted on FA, encompassing both physical parameters (particle shape, size distribution, fineness, and density) and chemical properties(chemical composition and heavy metal content). Mortar test specimens, with FA mixing ratios ranging from 5 to 20%, were produced in compliance with KS L 5405 standards, and their flow and compressive strength were subsequently measured. The test results indicated that the four types of FA exhibited particle sizes approximately between 20~30㎛, densities around 2.3~2.5g/cm³, and a fineness range of 2,600~4,900cm²/g. The FA comprised approximately 50~90% of components such as SiO₂, Al₂O₃, Fe₂O₃, and CaO, displaying characteristics akin to type-II and type-III FA of KS L 5405 standards, albeit with differences in chlorine and SiO₂ content. From the mortar tests, it was observed that the compressive strength of the mortar ranged between 34~47MPa when the pellet combustion FA was mixed in proportions of 5~20%. FA, produced exclusively from the combustion of 100% lignocellulosic fuel, is assessed to possess high recyclability potential as a substitute for conventional admixtures.