• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.264-270
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• 2016

This Study is to into fuel using a torrefation reaction to food waste. When the fuel of only food waste alone, fuel value is was performed at a ratio of sewage sludge constant attempts to prevent low. Mixing ratios of food waste and sewage sludge, 10:0, 8:2, 6:4, 5:5. Regardless mixing ratio, it was possible to confirm that decreases the moisture content of 10% or less at a reaction temperature of $240^{\circ}C$ or higher. As the ratio of the reaction temperature and the sewage sludge is high, the fixed carbon content is increased. It was measured at up to 36%(mixing ratios6:4, reaction temperature $270^{\circ}C$) from the initial 1.1%. From the reaction temperature $240^{\circ}C$ satisfied with 3000Kcal/Kg or more is a SRF criteria shows the calorific value. It was possible to obtain a heating value that is increased from the raw sample approximately sextuple. As reaction temperature is heightened, Van krevelen Diagram moved to the range of Lignite range. It was possible to obtain high fuel ratio and 5,500Kcal/kg or less of a combustility index as the sewage sludge mixing ratio becomes high. Increase the fixed carbon content, than those food waste alone solid fuel into and improved fuel costs, it is necessary to ensure that the quality of the fuel is improved.

• Clean Technology
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• v.27 no.1
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• pp.79-84
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• 2021

In this study, the waste activated carbon used in the painting process was filled into a cylindrical cartridge and the characteristics of desorption by low temperature gas were investigated. Adsorption and desorption experiments of toluene with activated carbon were conducted to determine the flow rate of desorption. In an experiment where desorption was performed while changing conditions at flow rates of 1, 2 and 4 ㎥ min-1, it was determined that 2 ㎥ min-1 was appropriate due to the high THC concentration and desorption time. In the early stage of the desorption of waste activated carbon, 2-butanone and MIBK (methyl isobutyl ketone) with a low boiling point were generated at a high rate in the gas component, and after that, the concentration of THC decreased and the BTX was desorbed at a high rate. The total calorific value of the gas component generated during the desorption of waste activated carbon was 316 kcal kg-1. From repeating the regeneration of waste activated carbon with toluene five times, it was observed that the iodine value and the specific surface area were relatively lower than that of new activated carbon. In the desorption experiment where two cylindrical cartridges were connected in series, the maximum THC concentration was about 470 ppm.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.49-57
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• 2016

In this study, a thermal hydrolysis technology was used to treat the poultry carcasses that were killed due to Avian Influenza (AI) occurrence, as well as to determine the possibility of fueling for the resultant products. Experimental results showed that the poultry carcasses were liquefied except for sand, and showed the optimum efficiency at $190^{\circ}C$ and operating time of 60 minutes. It has been shown that liquid products obtained after thermal hydrolysis has good conditions for fuel conversion since it had high carbon contents and calorific value, as well as low ash content. In addition, it was possible to operate the thermal hydrolysis facility by using only the waste heat generated in the combustion without injecting the auxiliary fuel, and the exhaust gas generated in the combustion has a small influence on the atmosphere.

• Clean Technology
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• v.24 no.4
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• pp.339-347
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• 2018

In order to cope with environmental problems and climate change caused by fossil fuels, renewable energy supply is increasing year by year. Currently, waste energy accounts for 60% of renewable energy production. However, waste has a lower calorific value than fossil fuels and contains various harmful substances, which causes serious problems when applied to power generation boilers. In particular, the chlorine in the waste fuel increases slagging and fouling of boiler heat exchangers, leading to a reduction in thermal efficiency and the main cause of high temperature corrosion, lowering facility operation rate and increasing operating cost. In this study, the high temperature corrosion experiments of superheater materials (ASME SA213/ASTM A213 T2, T12 and T22 alloy steel) by alkali chlorides were conducted, and their corrosion characteristics were analyzed by the weight loss method and SEM-EDS. Experiments show that the higher the temperature and chloride content, the more corrosion occurs, and KCl further corrodes the materials compared to NaCl under the same condition. In addition, the higher the chromium content of the material, the better the corrosion resistance to the alkali chlorides.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.3
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• pp.55-61
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• 2018

This study evaluated if the selected samples meets the Solid Refuse Fuel quality criteria in Korea. Biomass and plastic wastes generated in D City were mixed in diverse ratio. When the biomass content was about 40%, the moisture content was close to the SRF criteria and was measured to be 9.8%. The ash contents were analyzed up to 4.19%, and the lower calorific values based on Steuer, Dulong Equation and Bomb Calorimeter were at least 4,851, 4,181 and 3,847 kcal/kg, respectively. As a result of the elemental analysis, sulfur and chloride content were measured up to 0.05%. Those values satisfied the SRF criteria. Also, heavy metals(Hg, Cd, Pb, As) were analyzed to be below the SRF criteria. This makes it possible to use efficiently the wood byproducts abandoned in the woods, and the physical properties of wood being weak to moisture can be supplemented with plastics. Consequently, if plastic and biomass were well mixed and made into SRF, it would overcome the problem of shortening the life span of incineration facilities due to the high temperature of plastic wastes in the incinerator.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.48-59
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• 2018

This study was conducted to suggest the effective management and recycling processes of coffee waste, which can be easily obtained from coffee shops and coffee-related products industries. Prior to the fabrication of pellets, the potential of coffee waste as a raw material of pellet was investigated through the examination of its chemical compositions and fuel characteristics. Major gradient included in coffee waste was holocellulose, followed by fat/oil and protein. Coffee waste contained a small quantity of ash (0.7%), such as calcium, sodium, potassium and magnesium. Interestingly, coffee waste was easily dried probably due to its porous structure. Pellets fabricated with coffee waste and larch sawdust showed good fuel characteristics, such as moisture content, ash content, density and durability. The pellets exceed greatly the minimum requirements of $1^{st}$-grade wood pellet standard designated by National Institute of Forest Science (NIFOS). Particularly, the high calorific value of coffee waste showed the potential as a raw material of pellet. However, owing to high nitrogen and sulfur contents, coffee waste is like to be used as a raw material of wood pellet for combined heat and power plants equipped with a reduction system of $NO_x$ and $SO_x$ gases. On the other hand, 91 wt% larch sawdust and 9 wt% coffee waste are required to fabricate the $1^{st}$-grade wood pellets designated by NIFOS. Pellets fabricated with the conditions are estimated to have nitrogen content of 0.298% and sulfur content of 0.03%. Lastly, if amounts of coffee waste and sawdust in the production of wood pellets are adequately adjusted according to its purchasing price, the manufacturing cost of pellet can effectively be reduced. In addition, it is expected tp prepare the effective recycling process of waste and to relieve the environmental burden with the reduction of waste from the commercialization of coffee waste/larch pellets.

• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.258-267
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• 2017

In this study, pitch pine (Pinus rigida, PIR) and Mongolian oak (Quercus mongolica, QUM) pellets were fabricated with bark or/and drying waste liquor (DWL) of larch (Larix kaempferi, LAK) as an additive. Based on the results of fuel characteristics of the pellets, optimal conditions for producing the high-quality pellets were provided. In the analysis of chemical composition, bark contained holocelluose and lignin of 90% and over. DWL had 0.1% solid assumed to sugars which are generated from the oven-drying of LAK logs. QUM showed high ash content (2.2%) by containing of bark in the sawdust. Bark and DWL of LAK had high ash content of 4% and over. Calorific values of all specimens and additives were higher than that of the $1^{st}$-grade standard of wood pellets designated by NIFOS (18.0 MJ/kg). PIR and QUM pellets were fabricated with additive of 2 wt% based on the solid weight of oven-dried sawdust using a piston-type flat-die pelletizer, and thus ash content and calorific value of the pellets did not affect by the use of additive. Durability of the pellets increased with the use of additive. Durabilties of pellets, which were fabricated with bark as an additive and DWL as a controller of moisture content for sawdust, did not differ from those of pellets without additives and were lower than those of pellets either with bark or DWL. However, use of both bark and DWL for the production of wood pellets might be favorable because it can make a profit from the collection process of DWL. Based on the results of fuel characteristics of the pellets, QUM and PIR pellets were produced by a flat-die pelletizer. Moisture content (MC), bulk density and durability of the pellets improved with the use of additive. Particularly, sawdust MC of 10% and the addition of bark or DWL for PIR as well as sawdust MC of 12% and the addition of bark for QUM might be optimal conditions for the production of high-quality pellets. Except for the ash content of QUM pellets, other properties of PIR and QUM pellets exceeded the $1^{st}$-grade wood pellets standards of NIFOS.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.103-106
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• 2014

Recycling of bottom ash from municipal solid waste (MSW) incinerator has been strictly limited due to its composition of high level chlorine and other unfavorable substances. The composition of MSW has been, however, changed after the introduction of garbage-bag sales system, extended producer responsibility (EPR) policy and the prohibition of direct landfill of food waste. Recent waste shows reduced moisture and chlorine content, increased calorific value due to the separation of food waste, incombustible materials and PVC. The main purpose of this study is to investigate the trend of composition changes of MSW incinerator bottom ash and to compare the analytical results with those before the separation system was introduced. CaO content of bottom ash, one of the major component of cement clinker, increased from 26.7% in 2001 to 34.0% in 2006. The chlorine content showed a dramatic decrease from 1.84% in 2001 to 0.00655% in 2006, which is closely compatible with that of the fly ash of coal-utilizing thermal power plants, which is mainly due to the changes of MSW composition. It is eventually considered that there is a possibility of utilizing the incinerator bottom ash as a raw material of cement clinker feed substances.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.479-482
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• 2008

Since late of 2000, KIER has developed a novel pyrolysis process for production of fuel oils from polymer wastes. It could have been possible due to large-scale funding of the Resource Recycling R&D Center. The target was to develop an uncatalyzed, continuous and automatic process producing oils that can be used as a fuel for small-scale industrial boilers. The process development has proceeded in three stages bench-scale unit, pilot plant and demonstration plant. As a result, the demonstration plant having capacity of 3,000 tons/year has been constructed and is currently under test operation for optimization of operation conditions. The process consisted of four parts ; feeding system, cracking reactor, refining system and others. Raw materials were pretreated via shredding and classifying to remove minerals, water, etc. There were 3 kind of products, oils(80%), gas(15%), carbonic residue(5%). The main products i.e. oils were gasoline and diesel. The calorific value of gas has been found to be about 18,000kcal/$m^3$ which is similar to petroleum gas and shows that it could be used as a process fuel. Key technologies adopted in the process are 1) Recirculation of feed for rapid melting and enhancement of fluidity for automatic control of system, 2) Tubular reactor specially-designed for heavy heat flux and prevention of coking, 3)Recirculation of heavy fraction for prevention of wax formation, and 4) continuous removal & re-reaction of sludge for high yield of main product (oil) and minimization of residue. The advantages of the process are full automation, continuous operation, no requirement of catalyst, minimization of coking and sludge problems, maximizing the product(fuel oil) yield and purity, low initial investment and operation costs and environment- friendly process. In this presentation, background of pyrolysis technology development, the details of KIER pyrolysis process flow, key technologies and the performances of the process will be discussed in detail.

• Environmental Engineering Research
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• v.23 no.3
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• pp.250-257
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• 2018

We developed new composites by combining the solid waste from Low-Density Polyethylene in the form of plastic bag (PB) and biomass from rice husk (RH),in the form of $(RH)_x(PB)_{1-x}$ (x = (1, 0.9, 0.7, 0.5)), as alternative fuels for electrical energy sources, and for providing the best solution to reduce environmental pollution. Elemental compositions were obtained by using proximate analysis, ultimate analysis, and X-ray fluorescence spectroscopy, and the thermal characteristics were obtained from thermogravimetric analysis. The compositions of carbon and hydrogen from the ultimate analysis show significant increases of 20-30% with increasing PB in the composite. The activation energy for RH is 101.22 kJ/mol; for x = 0.9 and 0.7, this increases by 4 and 6 magnitude, respectively, and for x = 0.5, shows remarkable increase to 165.30 kJ/mol. The range of temperature of about $480-660^{\circ}C$ is required for combustion of the composites $(RH)_x(PB)_{1-x}$ (x = (1, 0.9, 0.7, 0.5)) to perform the complete combustion process and produce high energy. In addition, the calorific value was determined by using bomb calorimetry, and shows value for RH of 13.44 MJ/kg, which increases about 30-40% with increasing PB content, indicating that PB has a strong effect of increasing the energy realized to generate electricity.