• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.367-373
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• 2011

This research is a basic researching process for producing solid fuel that mixing paper sludge and Heat Transfer Medium Oil. Under the presence of Heat Transfer Medium Oil, paper sludge is heated and dried with home appliance microwave for comparing drying efficiency and energy efficiency of different types of drying method. As a result, Heat Transfer Medium Oil and paper mixing case of drying method, OMD, is the most efficient way to shorten the time for evaporating moisture in the paper sludge. In addition, heat transfer effect and density is increased with adding Heat Transfer Medium Oil by microwave. Future more, OMD's energy cost for evaporating whole moisture is 78% cheaper than MD. Also, OMD process shows the best energy efficiency with comparing other process. Evaporation rate of paper sludge evaporation process with microwave is 11.66% increased by adding Heat Transfer Medium Oil 150g. Preheating Heat Transfer Medium Oil or improving different ways injecting Heat Transfer Medium Oil is a good way to increase a rate of initiative moisture evaporation process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.660-667
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• 2018

This study examined the optimal manufacturing conditions of RDF using heat-dried sludge from sewage treatment plant in Cheonan with the oil-drying method. The amounts of oil evaporation and oil drying of the heat-dried sludge were measured at different temperatures to evaluate the value of the product. The performance of the product was then measured using a calorimeter and TGA. In addition, the concentration of odor, NH3, H2S, and TVOC during drying was determined using a portable odor-meter. Ingredient analysis was performed by EDS. Considering mass-production, the oil to heat-dried sludge weight ratio was fixed to 4:1. At $130^{\circ}C$, only physical mixing occurred after the instantaneous drying of internal water. Considering the eco-friendly aspects, there was no significant difference in the drying efficiency between $160^{\circ}C$ and $190^{\circ}C$. Therefore, the optimal conditions were a drying temperature of $160^{\circ}C$ within 5 minutes. Finally, the RDF manufactured in this study and fuel used in the thermal power plants were compared. The calorific value was 4,449kcal/kg, the water content was 2% and the ash content was 34%, which is higher than the fuel of thermal power plants. Therefore, it is believed that coal energy as well as wood pellets can be replaced.

• Clean Technology
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• v.15 no.3
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• pp.154-164
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• 2009

In 2007, 94% of organic wastewater sludge from industries located in Ulsan was disposed of by ocean dump. The ocean dump of organic sludge would be totally prohibited by the year of 2012. However, there is no alternative but incinerating the sludge from the industries located in Ulsan. Securing the technology for sludge treatment and on-land disposal is very important issue among the industries in the Ulsan Petrochemical Industry Complex. In this study, the material aspects of dried and carbonized sludge as a fuel were evaluated for petrochemical and sewage sludge from Ulsan. The dried and carbonized sludges from the factories producing terephthalic acid, BTX, propylene, chemical textile, etc. of which the low heat value exceeded 3,000 kcal/kg had high potential as a fuel according to the results of thermal characteristic analysis. However, the dried sludges with heat values lower than 2,100 kcal/kg and carbonized sludges, lower than 1,100 kcal/kg containing more Inorganic material from the industries producing pulp, paper, methylamine, amide, etc. had a little potential to be used as a fuel. In most cases, drying the sludge showed better results than carbonization in the aspect of thermal characteristics of sludge.

• Resources Recycling
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• v.31 no.6
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• pp.60-65
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• 2022

This study presents the carburization process for recycling sludge, which was formed during silicon wafer machining. The sludge used in the carburization process is a mixture of silicon and silicon carbide (SiC) with iron as an impurity, which originates from the machine. Additionally, the sludge contains cutting oil, a fluid with high viscosity. Therefore, the sludge was dried before carburization to remove organic matter. The dried sludge was washed by acid cleaning to remove the iron impurity and subsequently carburized by heat treatment under vacuum to form the SiC powder. The ratio of silicon to SiC in the sludge was varied depending on the sources and thus carbon content was adjusted by the ratio. With increasing SiC content, the carbon content required for SiC formation increased. It was demonstrated that substoichiometric SiC_x (x<1) was easily formed when the carbon content was insufficient. Therefore, excess carbon is required to obtain a pure SiC phase. Moreover, size reduction by high-energy milling had a beneficial effect on the suppression of SiC_x, forming the pure SiC phase.

• Journal of Environmental Science International
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• v.30 no.2
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• pp.135-143
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• 2021

This study executed evaluation of drying characteristics based on the polymer injection rate (8%, 10% and 12%) and the drying method[NIF(near-infrared ray). According to this study analyzed VS, VS/TS, and calorific value compared with 'the auxiliary fuel standard of the thermoelectric power plant and the combined heat & power plant'. The results are as follows. In the case of NIR, the VS was slightly changed at the early stage of the material preheating period and the constant drying rate period with low moisture evaporation. But VS reduction was shown higher as moisture was dried. In the case of non-digested sludge with high VS content, the VS reduction rate by drying was shown lower than that of digested sludge. As the flocculant injection rate increased, the VS loss due th drying was found to be small. Also, the higher the flocculant injection rate was the longer the drying time. Especially, in the case of the NIR drying equipment, as the moisture content of sewage sludge decreased(moisture content 20~40%), the loss of net VS also showed a tendency to increase sharply. It is shown that the high calorific value according to the drying time of the non-digested sludge was changed from 590 kcaℓ/kg to 3,005 kcaℓ/kg and from 539 kcaℓ/kg to 2,796 kcaℓ/kg.

• Journal of Hydrogen and New Energy
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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.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.5-11
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• 2023

This study was conducted to improve energy efficiency and problems such as clumping and fouling in the glue zone that occur in the moisture content range of 40 to 60% when sewage dehydration residue is directly fed into the dryer. The temperature of the hot air is low at 270~300℃, and the paddle-type flotation method and dehydrated residue are applied to the circulated heat storage media to increase the contact area with the hot air, thereby reducing energy recovery and gas emissions. The water content of the dried residue is 2.7. ~7 .5%, the heat of evaporation of moisture was 608.0~690.6 kcal/kg·H₂O, which confirmed an energy saving effect of about 8.8% compared to the heat of evaporation of moisture of 714.5 kcal/kg·H₂O when no heat storage media was used.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.443-450
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• 2019

We studied to find the optimal manufacturing conditions of coffee grounds sludge RDF with oil drying method. We expanded the lab scale to pilot scale to compare the efficiency of the oil-drying equipment and The selection of the ratio of coffee grounds and oil, the setting temperature, and the temperature change and water content with time were measured. In order to analyze the characteristics of the research results, characteristics of solid fuels produced(Coffee grounds of oil-dried) by calorimeter, TGA, combustion equipment, and combustion gas measuring instrument were analyzed. As a result, the ratio of oil to coffee grounds was 4: 1, and when the setting temperature was set to $300^{\circ}C$, the water content reached 10wt.% or less within 20 minutes. ln addition, it showed high calorific value of 6,273kcal/kg. However, coffee grounds had a similar composition to wood and showed high luminance and produced a lot of CO in combustion gas. As a result, it is considered to be unsuitable for thermoelectric power plant and camping fuel, but the initial ignition speed is high and the heat generation is high, so it is considered that it can replace the fuels for current use.