• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.526-531
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• 2009

This paper suggests the dehydration and RDF(Refuse Derived Fuel) production of organic sludge, livestock manure and sewerage sludge causing environmental problems, with hydrothermal pre-treatment process. The renewable technology from the organic wastes must involve short treatment time required, reusable energy source, anti-odor and viruses, low cost for the treatment, and well-fertilization. The hydrothermal pre-treatment process promotes to evaporate moisture in the sludge after being shortly treated in a reactor, which is supplied steam and heat by an external boiler, due to the pressure with steam breaks the cell walls of the sludge, so this process removes the internal moisture of the cell. Then, the treated sludge(solid-state) is mixed with waste vinyls called RDF(6,706kcal/kg).

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.5
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• pp.439-446
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• 2009

This paper investigates the dehydration and RDF (Refuse Derived Fuel) production of organic wastes, livestock manure and sewerage sludge with pressurized hydrothermal treatment process. The renewable technology for the organic wastes must involve short treatment time required, reusable energy source, anti-odor and viruses, low cost for the treatment, and well-fertilization. The pressurized hydrothermal treatment process promotes to evaporate moisture in the waste after being shortly treated in a reactor, which uses steam and heat supplied by an external boiler. By the pressurized steam, the cell walls of the waste break and effectively release the internal moisture. Then, the dried waste can be mixed with waste vinyls to produce RDF with a higher heating value as high as 6,700 kcal/kg.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.09a
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• pp.3-12
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• 2006

The main feature of these total technologies is that we can constitute the optimum treatment scheme fitting to the property of wastes, amount of wastes and energy requirement. For high moisture content wastes or biomass resources, high pressure steam process (MMCS) for crush, dry and deodorize wastes to produce high quality fertilizer of fuel is most appropriate. For dry or semi-dry solid wastes, the STAR-MEET system can be applied to produce low-BTU gases for power generation using duel fueled diesel engines of Stirling engines, and the REPRES and HyPR-MEET systems can be applied to produce hydrogen rich medium-BTU gas. For waste plastics and oils, liquefaction technology is best fit to produce light oil or kerosene equivalent fuel oils. These total technologies are completely different from the existent waste treatment technologies based on land-filling or incineration, and are expected to disseminate all over the world in the near future.

• Journal of the Korean Applied Science and Technology
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• v.22 no.4
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• pp.306-314
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• 2005

In this study, spherical $pre-BaTiO_3$ particles are prepared by gelation and aging process in autoclave without catalysts. The (Ba-Ti) gel used as a starting material was prepared by aging mixtures of titanyl acylate with barium acetate aqueous solution([glacial acetic acid (AcOH)]/[titanium isopropoxide (TIP)] 4, [barium acetate]/[TIP] 1) at $45^{\circ}C$ for 48hrs. XRD and SEM results for the (Ba-Ti) gel sample at aging process showed that the gel was formed via aggregation of the fine particles. It seems to be the primary particles of bulk (Ba-Ti) gel amorphous, but the spatial arrangement of barium and titanium in the (Ba-Ti) gel is similar to that in crystalline $BaTiO_3$ particles. From XRD and FT-IR. spectroscopy analysis it was found that the crystal structure of the prepared particles continuously transformed from amorphous to tetragonal as the calcination temperature increased, and crystallized spherical cubic and tetragonal $BaTiO_3$ powder obtained at the very low calcination temperature between $500^{\circ}C$ and $900^{\circ}C$ after 1hrs of heat treatment respectively. According to BET analysis result, final particle have pore structure of ink bottle shape which is produced by aggregation of fine spherical particles with surface area of $280m^2/g$ and average pore size of 130nm.

• Clean Technology
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• v.25 no.1
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• pp.74-80
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• 2019

Thermochemical treatment of sewage sludge is an energy-intensive process due to its high moisture content. To save the energy consumed during the process, the hydrothermal carbonization process for sewage sludge can be used to convert sewage sludge into clean solid fuel without pre-drying. This study is aimed to investigate co-firing characteristics of the hydrothermally carbonated sewage sludge (HCS) to a pulverized coal combustion system. The purpose of the measurement is to measure the pollutants produced during co-firing and combustion efficiency. The combustion system used in this study is a furnace with a down-firing swirl burner of a $80kW_{th}$ thermal input. Two sub-bituminous coals were used as a main fuel, and co-firing ratio of the sewage sludge was varied from 0% to 10% in a thermal basis. Experimental results show that $NO_x$ is 400 ~ 600 ppm, $SO_x$ is 600 ~ 700 ppm, and CO is less than 100 ppm. Experimental results show that stable combustion was achieved for high co-firing ratio of the HCS. Emission of $NO_x$ and $SO_x$ was decreased for higher co-firing ratio in spite of the higher nitrogen contents in the HCS. In addition, it was found that the pollutant emission is affected significantly by composition of the main fuel, regardless of the co-firing ratios.