신미수 Misoo Shin , 김용주 Yongju Kim , 이용국 Yongguk Lee , 장동순 Dongsoon Jang

DOI:10.9786/kswm.2016.33.1.1

Abstract

These days, the development of various pre- and post-combustion techniques has been pursued in order to reduce the emission of CO₂ in the fleet of coal-fired power plants, since it is of great importance to each country`s energy production while also being the single largest emitter of CO₂. As part of this kind of research efforts, in this study, a novel burning method is tried by the co-burning of the pulverized coal with the stoichiometric mixture of the hydrogen and oxygen (H₂+1/2O₂) called as HHO. For the investigation of this idea, the commercial computational code (STAR-CCM+) was used to perform a series of calculation for the IFRF (International Flame Research Foundation) coal-fired boiler (Michel and Payne, 1980). In order to verify the code performance, first of all, the experimental data of IFRF has been successfully compared with the calculation data. Further, the calculated data employed with pure coal are compared with the co-burning case for the evaluation of the substituted HHO performance. The reduced amount of coal feeding was fixed to be 30% and the added amount of HHO to produce a similar flame temperature with pure coal combustion was considered as 100% case of HHO addition. This value varies from 100 to 90, 80, 60, 50, 0% in order to see the effect of HHO amount on the performance of pulverized coal-fired combustion with the 30% reduced coal feeding. One of the most important thing found in this study is that the 100% addition of HHO amount shows approximately the same flame shape and temperature with the case of 100% coal combustion, even if the magnitude of the flow velocity differs significantly due to the reduced amount of air oxidizer. This suggests the high possibility of the replacement of the coal fuel with HHO in order to reduce the CO₂ emission in pulverized coal-fired power plant. However, an extensive parametric study will be needed in near future, in terms of the reduction amount of coal and HHO addition in order to evaluate the possibility of the HHO replacement for coal in pulverized coal-fired combustion.

Key Words

Combustion efficiency, Numerical simulation, Clean combustion technology

이철규 Cheal-gyu Lee

DOI:10.9786/kswm.2016.33.1.10

Abstract

Ozonation was performed for an effective removal of bisphenol A in laboratory scale batch reactor under various experimental conditions including the Al₂O₃ catalysts dosage, UV irradiation and temperature. Flow rate of ozone 1.0 L min^-1 and ozone concentration of 75 ± 5 mg L^-1 was maintained constantly, and the pH, COD and TOC were measured in 10 min intervals during oxidation processes for 60 min at 20℃. Our results confirmed that the O₃/UV, O₃/UV/Al₂O₃ in the ozonation improved the removal efficiency of both COD and TOC in solution compared with O₃ process alone. The pseudo first-order rate constants for the elimination of COD and TOC were calcluated to be 3.58 × 10^-4 sec^-1, 1.58 × 10^-4 sec^-1 and 7.98 × 10^-4 sec^-1, 3.42 × 10^-4 sec^-1 and activation energy was 1.44 kcal·mol^-1 and 2.32 kcal·mol^-1 at 20℃, respectively.

Key Words

Bisphenol A, Al₂O₃, Ozonation, Activation energy

김양기 Yang-gi Kim , 박송인 Song-in Park , 박현수 Hyun-soo Park , 하훈 Hoon Ha , 정경모 Kyeong-mo Jung

DOI:10.9786/kswm.2016.33.1.18

Abstract

This study was conducted to evaluate the emission characteristics of air pollutants from incineration facilities in Jeollanam-do. We selected 8 incineration facilities depend on type and the 19 items such as dust etc. were measured at the measurement hole for emission gas from air contamination control units. The range of emission concentrations for dust was 2.8 ~ 20.9 mg/Sm3 less than permissible air discharge standards. The results of 10 gaseous contaminants such as SOx was less than permissible air discharge standards. The range of emission concentrations for NOx was 13.4 ~ 120.0 ppm, less than permissible air discharge standards. As G facility was 112.4 ppm, 120.0 ppm, it exceeded emission standard (100 ppm) twice. The range of emission concentrations for HCl was ND ~ 85.300 ppm, B Facilitiy exceeded emission standard (20 ppm) as 85.300 ppm. The range of emission concentrations for NH₃ was ND ~ 76.333 ppm, A, D, H Facility exceeded emission standard (30 ppm). The concentration of each facility was 42.416 ppm, 62.930 ppm, 76.333 ppm. The results of heavy metals (5 items) showed within emission standards. G facility is operating in condition that input of urea is 100 L/day. If input of urea were changed to 50 ~ 75 L/day, the operating cost of air pollution prevention facility can be reduced by 25% ~ 50%. In this study, the correlation between urea input and nitrogen oxides was statistically significant, but the correlation between urea input and ammonia showed insignificantly. Our research attempts to evaluate the emission characteristics of air pollutants from incineration facilities and to institute a reduction plan, an effective management of incinerators.

Key Words

Air pollutants, Emission characteristics, Incinerator, Emission standard

남윤미 Yunmi Nam , 최종현 Jonghyun Choi , 장용철 Yong-chul Jang , 이진홍 Jin-hong Lee

DOI:10.9786/kswm.2016.33.1.29

Abstract

Aluminum can is one of the common and economically valuable recycling items in municipal waste streams. In this study, the reduction rate of the greenhouse gas emission and energy savings were estimated when aluminum cans are recycled by using material flow analysis, US EPA WARM method, and EU Prognos method. Based on the results, approximately 16,630 ton of aluminum in 2010 was recovered as ingot, while 10,873 ton of aluminum can to can recycling occurred in the same year. The reduction rate of aluminum recycling was estimated to be 240,986 tCO₂eq/yr by US EPA WARM method, while about 305,283 tCO₂eq/yr was found by the recycling using EU Prognos method. The difference resulted partly from the different system boundary and the loss rate during aluminum recycling process. The results of the energy savings and greenhouse gas reduction rate would be valuable for waste management policy makers to estimate the potential reduction rate of greenhouse gas by aluminum can recycling and accelerate recycling infrastructure of waste streams. This study also implies that the applications and results of both methods to estimate greenhouse gas reduction rates by aluminum can recycling should be carefully reviewed and acknowledged before the use of the method due to the different assumptions and results that are anticipated.

Key Words

Aluminum can recycling, GHG reduction, Energy savings, WARM, Prognos

정용길 Yong-gil Chong , 박진규 Jin-kyu Park , 김인희 In-hee Kim , 유문형 Moon-hyoung Yoo , 이남훈 Nam-hoon Lee

DOI:10.9786/kswm.2016.33.1.38

Abstract

The Intergovernmental Panel on Climate Change (IPCC) recommended the first order decay (FOD) model for estimating methane emissions from solid waste landfills. However, selecting appropriate parameter is a major challenge in methane emission modeling. The degradable organic carbon (DOC) and the fraction of degradable organic carbon which decomposes (DOC_F) are the two primary parameters in the methane generation potential (L₀). The DOC is the amount of organic carbon that can be decomposed by biochemical reactions in microorganisms. Chemical analysis methods are currently available to measure the DOC including using total organic carbon and element analysis methods. However, chemical analysis methods are not appropriate for determination of the DOC, which indicated that the DOC should be measured by biochemical tests. In addition, these methods should consider a fossil carbon content that needs a complex and high cost of analysis. The DOC_F is an estimate of the fraction of carbon that is ultimately degraded and released from landfills. However, no methodology is provided for determination of the DOC_F in landfills. Therefore, the purpose of this study was to suggest methodologies for the determination of DOC and DOC_F in solid waste landfills. A biochemical methane potential (BMP) test could be used to calculate the DOC because the BMP represents an upper limit on the methane potential of a waste, which corresponds to a maximal amount of degraded organic carbon. The calculation was based on the assumption that the DOC_F is 100%. In this study, two methodologies were suggested to determine the DOC_F in landfills. The first one uses a new equation (DOC_F = 2.76W-0.44) with moisture content in the landfill that actual methane flux data are unavailable. Moisture content is a major ecological parameter on the anaerobic biodegradability of the solid waste in the landfill. Another methodology is to use _L0,Landfill/L _0,BMP ratio. The L _0,Landfill could be determined by a regression analysis if methane flux data were available.

Key Words

Greenhouse gas, Solid waste landfill, L₀, DOC, DOC_F

Patricia. J. Abdulai , Sookoo Lee

DOI:10.9786/kswm.2016.33.1.46

Abstract

The objective of this study is to investigate the potential use of MSW incineration fly ash as an economic material for the removal of heavy metals (Pb, Mn, Fe, and Cu) from AMD. Batch adsorption experiment was conducted to examine the effects of pH, adsorbent dosage and contact time on metal ions removal in synthetic AMD using MSW incineration fly ash. Precipitation of calcium hydroxide and sodium hydroxide was used for comparison with MSW incineration fly ash by adjusting the pH (5 ~ 11) by coagulation method with 20 min reaction time. Comparing the application of Ca(OH)₂ and Na(OH), fly ash proves more efficient which may be due to its porosity and chemical composition. The results from adsorption studies showed that maximum adsorption rate was achieved at 0.4g dose when various fly ash dosages were added to the solution with 60 min optimum time and removal efficiency of heavy metals was over 96%. The effectiveness of fly ash can be related to its high calcium (CaO 55%) content. Efficiency of heavy metals removal was directly linked to the amount of fly ash in the reaction mixture and to the final pH attained. pH plays a significant role in heavy metal uptake. The main removal mechanism was adsorption at the surface of the fly ash together with the precipitation and co- precipitation from the solution with chemicals. Therefore the use of MSW incineration fly ash for treatment of AMD would represent a new market opportunity for this waste product. It can also be useful for neutralizing AMD and possibly reduce its adverse effects to the environment with efficient removal of metal ions from AMD.

Key Words

Acid mine drainage, Heavy metals removal, Fly ash, Adsorption, Coagulation

이희성 Hee-sung Lee , 전태완 Tae-wan Jeon , 황동건 Dong-gun Hwang , 강영렬 Young-yeul Kang , 장미정 Mi-jeong Jang , 유혜영 Hye-young Yoo , 홍수연 Soo-youn Hong , 박선오 Seon-oh Park , 김태희 Tae-hee Kim , 신선경 Sun-kyoung Shin , 안도요시토 Yoshito

DOI:10.9786/kswm.2016.33.1.56

Abstract

This study focused on enhancing the mechanical properties and thermal stability of bio-composites with natural agricultural residues and improving the interfacial adhesion between polymer and biodegradable agricultural residual waste fibers. To achieve this purpose, we proposed superheated steam (SHS) treatment method as a novel pre-treatment of fiber for improved of compatibility in polymer matrix. The use of SHS-treatment was investigated as a method for improving interfacial adhesion between agricultural residual waste fibers and polymer and with the goal of enhancing mechanical properties. We selected wheat straw fibers for agricultural waste fibers to improve the surface modification. Wheat Straw Fibers (WSF) was treated with SHS in order to modify its characteristics for bio-composite applications. Treatment was conducted at temperatures 200℃ and 230℃ for each 1 h. SHS-treated WSF was evaluated for its chemical composition, thermal stability, morphology and crystallinity. Thermal stability of the fibers was investigated using thermogravimetric analysis and found that the degradation temperature of the fibers is increased after of the SHS treatment. In addition, SHS treatment contained in the WSF reduce the rate of hemicellulose components. The WSF is polar nature of lignocellulose due to the presence of hydroxyl and carboxyl groups in cellulose and hemicellulose causes it to be incompatible with non-polar thermoplastics. SHS-treatment was found to be able to remove hemicellulose, which is the most hydrophilic and most thermally unstable component in WSF, since it has the lowest thermal resistance. Removal of hemicellulose makes the fiber less hydrophilic and this will potentially increase the compatibility of treated WSF and polymers and improves the mechanical properties and water resistance of composites.

Key Words

Bio-composites, Surface modification, Agricultural waste, Compatibility, Superheated steam (SHS)

Soo-ho Park , Thanh Cong Hoang , Jongo Kim , Woo-bum Lee

DOI:10.9786/kswm.2016.33.1.66

Abstract

The objective of this study was to examine the torrefaction process of three lignocellulose biomasses (rice husks, coffee shell, and wood) produced in Vietnam. Three different torrefaction temperatures ranging from 200℃ to 300℃ and three residence times of 20, 40, and 60 min were considered. The result showed that temperature had a higher effect on torrefaction process of biomass than residence time. Based on the findings of this study, a residence of 40 min could be suggested for an effective and proper torrefaction process to recycle the agricultural biomass and wood at 300℃. The torrefied products become fuel sources which can be applied to replace with fossil fuels.

Key Words

Biomass, Torrefaction, Mass yield, Elemental composition, Energy density

박은영 Eun-young Park , 김용진 Yong-jin Kim , 정승미 Seung-mi Jeong , 이동훈 Dong-hoon Lee

DOI:10.9786/kswm.2016.33.1.75

Abstract

We investigated optimal conditions for the hydrolysis of Laminaria japonica using a single enzyme such as Celluclast 1.5 L, Saczyme, and alginate lyase, for the production of reducing sugar. Redesigned experimental conditions including the optimal conditions determined for the single enzyme were proposed, and the hydrolysis of Laminaria japonica was also performed with a mixture of enzymes. The reducing sugar yield with the mixed enzymes was lower than that with Celluclast 1.5 L, which showed the highest efficiency among the enzymes used. Considering the reducing sugar yield and economics, it would seem that hydrolysis by mixed enzymes had no advantage. The coefficient of determination (R²) of Y₁ (the yield of reducing sugar by Celluclast 1.5 L) was 0.89. The P value of Y₁ was < 0.001, indicating statistical significance. By the response surface methodology (RSM), the optimum reaction conditions for hydrolysis of Laminaria japonica by Celluclast 1.5 L were determined to be enzyme of 8.0%, a reaction time of 26.4 h, a pH of 4.0, and a temperature of 42.6℃, resulting in the production of 117.7 mg/g-Laminaria japonica.

Key Words

Enzyme, Laminaria japonica, Hydrolysis, Response Surface Methodology (RSM)

리앙징 Jing Liang , 임병란 Byung Ran Lim , 이수구 Soo Koo Lee

DOI:10.9786/kswm.2016.33.1.85

Abstract

This study was performed to find the effect of Enteromorpha prolifera as a biosorbent on the removal of heavy metals such as lead, copper, zinc and cadmium from the synthetic wastewater. The biosorption experiment was conducted using biomass of dried Enteromorpha prolifera, which has caused environmental pollution issues in oceans and lakes. To find the physico-chemical characteristics and adsorption capacity, parameters such as biosorbent dosage, initial heavy metal concentration, pH value of solution, contact time which influence the effects on heavy metals removal were changed and the optimum values were found through batch test. The experimental results showed that the sequence for adsorption capacity of heavy metals by Enteromorpha prolifera was Pb²⁺> Cu²⁺> Cd²⁺> Zn²⁺. The optimum conditions of pH, contact time and dosage of biosorbent were pH 5.0, 60 min. and 0.5 g/L, respectively. As initial heavy metal concentration increased, the adsorption capacity increased up to 17.53 mg/g for Pb with 98% removal efficiency. From the adsorption thermodynamic and kinetic analysis, the biosorption pattern of Pb, Cu, Zn and Cd was well described using Freundlich and Langmuir sorption isotherm with their R² values of 0.99 and 0.97, respectively. The sorption kinetics followed pseudo-second order kin etic models and thus supported chemical sorption rather than internal diffusion. The work clearly indicates the potential of using Enteromorpha prolifera as an excellent adsorbent for heavy metal removal in industrial wastewater.

Key Words

Biosorbent, Enteromorpha prolifera, Heavy metal, Adsorption isotherm

유윤성 Yunsung Yoo , 조호용 Hoyong Jo , 강동우 Dongwoo Kang , 이민구 Min-gu Lee , 이상엽 Sang Yup Lee , 홍범의 Bum Ui Hong , 최창식 Chang Sik Choi , 박진원 Jinwon Park

DOI:10.9786/kswm.2016.33.1.92

Abstract

This research deals with carbon dioxide utilization using amino acid salt solution. Energy-efficient CCU (carbon capture and utilization) technology in which no thermal desorption step is required was suggested. Waste concrete was considerd as Ca²⁺ source. (1.5 M potassium glycinate + 0.15 M piperazine) was used. After solution is saturated with carbon dioxide, 25wt% 100 ml of calcium chloride solution to replace Ca²⁺ from waste concrete in experiment was added. And then, precipitated calcium carbonate (PCC) was formed. As a result of absorption experiments of (1.5 M potassium glycinate + 0.15 M piperazine), CO₂ loading value for the first absorption and reabsorption step was 0.7354 and 0.2848 mol CO₂/ mol absorbent, respectively. Also, the yield of PCC formation of (1.5 M potassium glycinate + 0.15 M piperazine) was 43.63%. Based on these data, the amount of CO₂ reduction was calculated. Calcium carbonate can be classified into calcite, vaterite, and aragonite according to their crystal structures and morphology. XRD and SEM analysis were performed and the result showed that the morphology of produced PCC salt was vaterite.

Key Words

CO₂ absorption, Glycine, Waste concrete, Amino acid salt, CCU

송연민 Yun Min Song , 석종혁 Jong Hyuk Seok

DOI:10.9786/kswm.2016.33.1.101

Abstract

The purpose of this study is to investigate the regional waste discharge and characteristics in Incheon Metropolitan City, and to evaluate the potential energy recovery for combustible wastes being discharged from Incheon province as well as currently being landfilled in the Sudokwon Landfill Site. Approximately, 2,466 ton and 0.879 kg/(capita·day) were estimated for annual average discharge of domestic wastes and daily domestic waste discharge rate per person in Incheon during the period from 2007 to 2013. The least squares methodology indicates those values to decrease to 1,120 ton and 0.347 kg/(capita·day), respectively in year 2021. The assessment of potential energy recovery for the landfilled household solid wastes indicated that total energy of 1.00 × 10⁷ GJ and 212 billion Won of electric charges could be recovered and saved each year. For the construction wastes, recoverable annual energy and electric charges were 1.04 × 10⁷ GJ and 269 billion Won, respectively.

Key Words

Potential energy recovery, Wastes, Landfill