• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.3
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• pp.44-53
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• 2011

Siloxane, organo-silicon compound, is used in the various forms of products such as cosmetics and detergents due to its quality physical chemistry attributes. Siloxane included in landfill gas which is caused in the process of decomposing of such products after landfill has imposed negative impacts on the operation of landfill gas utility facilities. The objective of this study was to investigate the siloxane production characteristics depending on the features of various landfill site in Korea so that the analysis was made on the landfilling age and landfill waste by in terms of its concentration, structure and composition. As for the concentration of siloxane depending on time passage, 12 landfill sites were reviewed by landfilling age. As for production attributes change of siloxane by landfill wastes, the source of wastes, physical production ration and siloxane concentration were compared in 6 landfills. The average concentration of total-siloxane within LFG is $6.75mg/m^3$ and cyclic-siloxane out of it occupies over 93%. By element, D4 and D5 in order take the highest proportion regardless of total-siloxane concentration and landfilling age. Even though this study is not able to verify the different impact of each kind of wastes on the generation of siloxane, it is confirmed that total-siloxane and cyclic-siloxane decrease in line with the increase of landfilling age as it does in the first order decay model for landfill gas.

• Journal of the Korean Institute of Gas
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• v.11 no.2 s.35
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• pp.5-9
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• 2007

There have been 3E problems of energy, economy and environment since the earth has its history. Especially, the energy and environment problems have been getting serious after the modem industry revolution. Therefore, the demand of gas as an eco-friendly energy source is getting increased. With the demand of gas, the installation and use of gas boiler is also increased, so human life injury by the waste gas(CO) of boiler goes on increasing every you. Hence, we want to find out the harm to human body through the study on the concentration of CO by the length of the straight exhaust tube of gas boiler. The allowable concentration of CO is 50 ppm. The 3 m of once bended tube starts exceeding the allowable concentration of CO after 5 minutes, and the 4 m and 5 m starts exceeding after 3 minutes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.1
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• pp.65-78
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• 2007

The pollutants (Rn, CH, CO, HS, radioactive gas from radiolysis) were generated from the process of construction and operation of underground repository, and after disposal of low-intermediate radioactive waste inside there must be controlled by a ventilation system to distribute them in area where enough air is supported. Therefore, a suitable technical approach is needed especially at an underground repository that is equipped with many entry tunnels, storage tunnels, exhaust-blowing tunnels, and vertical shafts in complicated network form. For the technical approach of such a ventilation system, WIPP (Waste Isolation Pilot Plant) in U. S and SFR (Slutforvar for Reaktorafall) low-intermediate radioactive waste repository in Sweden were selected as the models, for calculating the required air quantity, organizing a ventilation network considering cross section, length, surface roughness of the air passage, and describing a calculation of resistance of each circuit. Based on these procedures, a best suited ventilation system was completed with designing proper capacity of fans and operating plan of vertical shafts. As a result of comparing the two repositories based on the geometry dimensions and ventilation facility equipment operation, more parallel circuit as in WIPP, brought decrease in resistance for entire system leading to reduce of operating costs, and the larger cross-sectional area of the SFR, the greater the percentage of disposal capacity. Accordingly, the mixture of parallel circuit of WIPP repository for reducing resistance and SFR repository formation for enlargement of disposal capacity would be the most rational and efficient ventilation system.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.23-28
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• 2017

Pyrolysis characteristics of waste plastic films were investigated by using a thermogravimetric analysis and pyrolyzer-gas chromatography/mass spectrometry. Thermogravimetric analysis results revealed that the pyrolysis of waste plastic films can be divided into two distinct reactions; (1) the decomposition reaction of starch at between 200 and $370^{\circ}C$ and (2) that of other plastic polymers such as PS, PP, PE at between 370 and $510^{\circ}C$. The kinetic analysis results obtained by using the revised Ozawa method indicated that the apparent activation energy of the pyrolysis reaction of waste plastic films was also changed dramatically according to the different decomposition reactions of two major waste plastic film components. Py-GC/MS results also revealed that the typical pyrolyzates of each polymer in waste plastic films were levoglucosan (starch), terephthalic acid (PET), styrene monomer, dimer, and trimer (PS), methylated alkenes (PP), and triplet peaks (PE) composed of alkadiene/alkene/alkane. The phthalate, used as a polymer additive, was also detected on the pyrogram of waste plastic films mixture.

• Clean Technology
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• v.25 no.1
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• pp.40-45
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• 2019

In this study, nitrous oxide ($N_2O$) emission concentration was measured 3 times continuously for 24 hours from August 27, 2018 to October 22, 2018 and non-dispersive infrared (NDIR) spectrometer was used to calculate $N_2O$ concentration of exhaust gas from municipal solid waste (MSW) incinerator. As a result of $N_2O$ emission characteristics, it is estimated that $N_2O$ emission concentration is due to the difference of furnace temperature, oxygen concentration rather than the chemical component of waste. The measured $N_2O$ emission concentration of MSW incinerator was obtained in the range of 53.6 ~ 59.5 ppm and the total average concentration was measured 55.6 ppm. Therefore, the amount of $N_2O$ emissions calculated from the $N_2O$ concentration was $98.05kg\;day^{-1}$ on average and the amount of $N_2O$ distribution in the range of $90.41{\sim}108.44kg\;day^{-1}$ was obtained. As a result, the $N_2O$ emission factor of the MSW incinerator was estimated to be $1,066.13g_{N_2O}\;ton_{waste^{-1}}$. The estimated $N_2O$ emission factor of the MSW incinerator was 20 times higher than calculated emission factor used in the Tier 2 method. Consequently, it is considered that the method of calculating the amount of $N_2O$ emission in the MSW incineration facilities using waste type and incineration amount needs to be supplemented to ensure accuracy.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.69-84
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• 2023

Despite the continuous installation and regular inspection of waste treatment facilities, complaints about excessive incineration and illegal dumping stench continue to occur at on-site treatment facilities. In addition, field surveys were conducted on the waste treatment facilities currently in operation (6 type) to understand the waste treatment process for each field, to grasp the main operating factors applied to the inspection. In addition, we calculated the material·energy balance for each main process and confirmed the proper operation of the waste disposal facility. As a result of the site survey, in the case of heat treatment facilities such as incineration, cement kilns, and incineration heat recovery facilities, the main factors are maintenance of the temperature of the incinerator required for incineration and treatment of the generated air pollutants, and in the case of landfill facilities Retaining wall stability, closed landfill leachate and emission control emerged as major factors. In the case of sterilization and crushing facilities, the most important factor is whether or not sterilization is possible (apobacterium inspection).In the case of food distribution waste treatment facilities, retention time and odor control during fermentation (digestion, decomposed) are major factors. Calculation results of material balance and energy resin for each waste treatment facility In the case of incineration facilities, it was confirmed that the amount of flooring materials generated is about 14 % and the amount of scattering materials is about 3 % of the amount of waste input, and that the facility is being operated properly. In addition, among foodwaste facilities, in the case of an anaerobic digestion facility, the amount of biogas generated relative to the amount of inflow is about 17 %, and the biogas conversion efficiency is about 81 %, in the case of composting facility, about 11 % composting of the inflow waste was produced, and it was comfirmend that all were properly operated. As a result, in order to improve the inspection method for waste treatment facilities, it is necessary not only to accumulate quantitative standards for detailed inspection methods, but also to collect operational data for one year at the time of regular inspections of each facility, Grasping the flow and judging whether or not the treatment facility is properly operated. It is then determined that the operation and management efficiency of the treatment facility will increase.

• Clean Technology
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• v.30 no.1
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• pp.37-46
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• 2024

Environmental problems caused by plastic waste have been continuously growing around the world, and plastic waste is increasing even faster after COVID-19. In particular, PP and PE account for more than half of all plastic production, and the amount of waste from these two materials is at a serious level. As a result, researchers are searching for an alternative method to plastic recycling, and plastic pyrolysis is one such alternative. In this paper, a numerical study was conducted on the pyrolysis behavior of non-condensable gas to predict the chemical reaction behavior of the pyrolysis gas. Based on gas products estimated from preceding literature, the behavior of non-condensable gas was analyzed according to temperature and residence time. Numerical analysis showed that as the temperature and residence time increased, the production of H₂ and heavy hydrocarbons increased through the conversion of the non-condensable gas, and at the same time, the CH₄ and C₆H₆ species decreased by participating in the reaction. In addition, analysis of the production rate showed that the decomposition reaction of C₂H₄ was the dominant reaction for H₂ generation. Also, it was found that more H₂ was produced by PE with higher C₂H₄ contents. As a future work, an experiment is needed to confirm how to increase the conversion rate of H₂ and carbon in plastics through the various operating conditions derived from this study's numerical analysis results.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.837-842
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• 2012

A pilot scale circulating fluidized boiler (CFB) for refuse derived fuel (RDF) is designed and constructed to demonstrate a performance of CFB technology for waste fuel utilization. The boiler has a design capacity of 6 MWth with $400^{\circ}C$ 38 ata steam generation performance. The maximum steam rate of the boiler was about 8 ton/h. The main component of the fuel was RDF (Refuse Derived Fuel) with high volatile contents and showed fast ignition and easy combustion. The pilot plant showed over 99.5% of combustion efficiency. Stable operation of RDF CFBC depended on the content of non combustion materials other than ash and fast removal of them. Emission level was under legal limit except that of HCl without external flue gas treatment facilities. Also about 60% of fuel chlorine was absorbed to fly ash particles. For HCl emission control flue gas treatment technology is required such as wet and dry scrubber in order to comply with Korean regulation.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.25-33
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• 1999

The recent emergence of biofiltration as a cost effective waste-gas control technology has stimulated in European countries and the USA. Biofiltration of soil vapor extraction off-gas from gasoline contaminated site was simulated in lab-scale in this study. A filling material used was a compost. This study was conducted to evaluate biofiltration characteristics of the compost material for gasoline off-gas. TPH elimination capacity at the gas loading rate of about 50g/$\textrm{m}^3$((filling material)/hr was circa 40g/$\textrm{m}^3$((filling material)/hr. Removal rate of xylene was the highest among BTEX. while it was the lowest in case of bezene. The maximum elimination capacity of the compost was about 1.5g/$\textrm{m}^3$((filling material)/hr for benzene. More than 95% of trimethylbenzene and naphtalene were removed below the loading rate of 0.7g/㎥(filling material)/hr. About 80% of total TPH and BTEX were removed by biodegradation.

• Journal of the Korean Wood Science and Technology
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• v.14 no.2
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• pp.21-28
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• 1986

A quartz type gasification reactor was designed and used for pyrolysis and gasification of sawdust, ricestraw and ricehusk. The initial reaction temperature was 350$^{\circ}C$, and up to 550$^{\circ}C$ to complete pyrolysis and gasification reaction. In order to examine the effect of catalyst on reaction temperature, $K_2CO_3$ and $Na_2CO_3$ as catalyst were also used. The product gas mixtures are identified to be CO, $CO_2$, $CH_4$ and $CH_3CHO$ etc. by Gas Chromatography and Mass Spectrometer. The highest gas volume of the gasified sawdust at 550$^{\circ}C$ amounts to 1800ml/g of sawdust, even though the yield and composition of this product gas are depending on the reaction temperature of the reactor and catalyst used.