이승희 Seung-whee Rhee

DOI:10.9786/kswm.2019.36.7.583

Abstract

As 45% of bio-solid recovered fuel (bio-SRF) materials were imported from foreign countries in 2017, it is necessary to expand the supply of bio-SRF using organic waste in Korea. To promote the supply of domestic-waste-based bio-SRF, a mixture of animal manure and biomass with low ash content was considered for use as a renewable energy source, such as carbonization residue. However, most studies on the carbonization of animal manure have been carried out on a laboratory scale, and there is little research on the energy efficiency of the carbonization process of animal manure at the pilot-plant scale. Therefore, it is necessary to evaluate factors such as mass and energy yields in the bio-SRF manufacturing process on a pilot-plant scale. In this study, swine manure and woody waste were used in the carbonization process on a pilot-plant scale to evaluate energy efficiency. In a pilot-plant scale carbonization system, the manufacturing processes consists of the drying process, crushing process, separation process, mixing process, carbonization process, and waste gas treatment process. To evaluate the energy efficiency for the carbonization processes on a pilot-plant scale, the mass yield, energy yield, and energy density of the bio-SRF manufacturing were reviewed. Of the 3,000 kg of mixed materials, 1,146 kg was recovered as carbonization residue, obtaining a mass yield of 38.2%. In addition, the energy yield of the entire process was estimated to be 73.3%, with energy density measuring at 1.92. These results indicate that the carbonization process on a pilot-plant scale is reasonably energy efficient.

Key Words

Energy efficiency, Swine manure, Woody waste, Carbonization, Pilot plant

이유민 You Min Lee , 이성미 Seong Mi Lee , 김혁진 Hyeok Jin Kim , Poudel Jeeban , 오세천 Sea Cheon Oh

DOI:10.9786/kswm.2019.36.7.592

Abstract

While the world relies heavily on energy production using fossil fuels, the alarming impact of fossil fuel use on the environment has led to increasing research into application of alternative energy sources such as biomass. Among the various pathways of using biomass as a substitute energy source, biodiesel from transesterification of biomass has the advantage of lower net CO₂, lower sulfur content, and improved biodegradation as compared to readily available diesel. However, proper selection of raw material for biodiesel production is crucial, as the unprocessed material may be contaminated. In this regard, coffee grounds, which would otherwise be discarded, make a good source of biodiesel. As of 2017, 130,000 tons of coffee grounds were produced and disposed of, except for a small amount used for fertilizer and deodorizing purposes. Our research study was conducted to investigate the characteristics of biodiesel synthesis through soxhlet extraction using coffee grounds. The optimum reaction conditions were determined by varying potassium hydroxide (KOH) and methanol (MeOH) concentrations, retention times and transesterification temperatures. In addition, from the characteristic analysis of the liquid product using GC and GC/MS analysis, 76% of biodiesel was obtained.

Key Words

Coffee grounds, Biodiesel, Soxhlet extraction, Base catalyst, Transesterification

박훈채 Hoon Chae Park , 최명규 Myung Kyu Choi , 최항석 Hang Seok Choi

DOI:10.9786/kswm.2019.36.7.601

Abstract

In order to investigate the heat transfer of carbon black from waste tire pyrolysis, the particle cooling of carbon black was simulated using computational fluid dynamics (CFD). In the present study, the effects of cooling temperature and particle mixing were investigated. As the cooling temperature decreases, the cooling rate of carbon black increases. However, the particle mixing had a great influence on the particle-particle (wall) conductive heat transfer. The cooling rate of carbon black was more strongly influenced by particle mixing than the influence from cooling temperature. Also, during mixing cooling, the cooling efficiency according to the with or without of paddle screw was analyzed. The experimental and CFD analysis results can be further applied to the design of the screw conveyor cooler.

Key Words

Carbon black, CFD, Fast pyrolysis, Heat transfer, Waste tire

이상엽 Sang-yeop Lee , 박세원 Se-won Park , 정연욱 Yean-ouk Jeung , 한건호 Gun-ho Han , 서용칠 Yong-chil Seo , 김우현 Woo-hyen Kim

DOI:10.9786/kswm.2019.36.7.608

Abstract

Conventional sewage sludge is treated through incineration, landfill, and fertilization. However, interest in sludge treatment has increased due to problems with treatment costs after the generation of environmentally hazardous materials such as heavy metals, viruses, and high moisture content. Therefore, in this study, a hydrothermal treatment was applied to properly treat and use the sludge as an energy source. The reaction was carried out for 1 hour at the optimum temperature of 200℃ to reduce the moisture content of the sample, and increase the calorific value to improve the fuel quality. The improved sample was used to determine the value of the fuel by applying it to a gasification technique, which is a thermal treatment. The calorific value of syngas of sludge gasification was 1,041.57 kcal/kg, and the lower calorific value of syngas after hydrothermal treatment was 1,242.59 kcal/kg. In addition, the cold gas efficiency increased from 39.5% to 45.3%, and pollutants such as HCN, HCl, NH₃, and tar decreased. As a result of the overall characteristics, the hydrothermaltreated sludge is considered to be of sufficient value as a fuel for gasification technology.

Key Words

Sewage sludge, Hydrothermal, Gasification, Moisture, Gas pollution

양원석 Won-seok Yang , 권영현 Young-hyun Kwon , 최경구 Gyung-goo Choi , 이원석 Won-seok Lee , 이은송 Eun-song Lee , 김기헌 Ki-heon Kim

DOI:10.9786/kswm.2019.36.7.617

Abstract

A general waste composition analysis, consisting of a proximate analysis, has been presented. The definition and usage of terms were clarified, and all terms should be combined with their respective units. In this study, a proximate analysis method was applied to bottom ash, rubbers, automobile shredder residue, plastics, sewage sludge, and waste water sludge in considering the characteristics of individual waste. It has been observed that this proximate analysis method, based on the characteristics of individual waste, required drying the waste for more than 6 hr, until the moisture contents reached between 105 to 110℃ and a constant weight. It has been suggested that 2 hr of ignition at a maximum 850℃ for ash is recommended.

Key Words

Waste composition, Three components, Proximate Analysis, Combustible matter

이은송 Eun-song Lee , 백승기 Seung-ki Back , 조수진 Soo-jin Cho , 김기헌 Ki-heon Kim , 서용칠 Yong-chill Seo

DOI:10.9786/kswm.2019.36.7.624

Abstract

This study provides the correlation between mercury (Hg) content and leachate concentration of fly ash (FA) from waste incinerators: a municipal solid waste incinerator (MSWI) and a medical waste incinerator (MWI). In addition, the stability and leaching characteristics of Hg were estimated to develop stabilization treatment technology for hazardous waste having the leachate Hg concentration as 0.005 mg-Hg/L based on the waste management law in Korea. As a result of a sequential extraction procedure consists of five-steps, FA (MSWI) and FA (MWI) contained mainly unstable mercury compounds with high solubility or sensitive to changes in pH. The major constituents were found to be Ca, Fe and Si by the x-ray fluorescence analysis. The high alkalinity ([Ca]/[Si]) could affect the conversion of Hg compounds to amphoteric ions, then could contribute to the increasing of F3 fraction from the sequential extraction procedure. Fe could affect oxidation of Hg and increasing the production of HgO. These factors could affect the increase in mobility of Hg compounds in fly ash; spraying lime (Ca(OH₂) in air pollution control devices also could affect the high mobility of Hg compounds. Therefore, the development of control technology (e.g. stabilization) of discharged fly ash by considering the chemical properties and stability.

Key Words

Mercury, Content, Leaching, Stability, Sequential extraction procedure

박세원 Se-won Park , 이상엽 Sang-yeop Lee , 정연욱 Yean-ouk Jeong , 한건호 Gun-ho Han , 서용칠 Yong-chil Seo

DOI:10.9786/kswm.2019.36.7.632

Abstract

In this study, the gasification process was operated using various feedstocks, including biomass, waste, and fossil fuel. Sawdust, waste solid refuse fuel, and coal were selected as the representative for the feedstocks. In the case of waste fuel, it must be utilized as a new and renewable energy, rather than a disposed target. A comparative study on feedstock type was conducted, and the feedstocks were applied to a lab-scale downdraft fixed bed gasification process. The experimental conditions were maintained for the assessment of the gasification process’s applicability, and the deduction of the optimum equivalent ratio of feedstock. The results of the study revealed that the waste solid refuse fuel was more applicable to the gasification process than coal and sawdust, with an optimal equivalent ratio of 0.4 in all feedstocks, and the highest cold gas and carbon conversion efficiency. Detailed results showed that cold gas efficiency was 50.94%, and carbon conversion ratio was 54.66% from waste gasification. In further studies or researches, gasification technologies using waste, biomass or coal were continuously conducted for development of high efficient technology. This study could potentially be used as reference data for gasification operations at commercial plants.

Key Words

Feedstock, Biomass, Fossil fuel, Waste, Gasification

유흥민 Heung-min Yoo , 정택호 Taek Ho Chung , 이상엽 Sang-yeop Lee , 박세원 Se-won Park , 서용칠 Yong-chil Seo

DOI:10.9786/kswm.2019.36.7.644

Abstract

There are many issues related with environment in the world. As time goes by, it would be main problems for present generations in the near future. Especially, the problems for air pollutant including particulate matter (PM) need to be resolved among locals or nations. In order to develop the renewable energy sources sustainably, the facility operators should prove the harmlessness for environments, such as atmosphere, water, and health risk. In Korea, the government is faced with these problems. Especially, local citizens have been demanding suspension of operating and using the fluffsolid refused fuel (SRF) in combined heat and power plants. According to this problem, the government has announced the 4th master plan for renewable energy in Korea, one of the main contents is to decrease supplement proportion of the ‘waste to energy’ part from approximately 68 % to 29 %. However, this master plan could cause ‘combustible waste congestion’ because the balance between supply and demand was not considered. Thus, the efficient method to resolve should be developed, while considering the balance. To solve these issues, many researchers have been suggesting and researching to establish a tracking technology on air pollutant sources. It may serve an appropriate solution to us in the near future, if it can identify the air pollutant sources among variable sources, such as combined heat and power plant, a lot of vehicles, and another sources. In this study, the carbon isotope was used to identify sources among SRF, gasoline, diesel and motorcycles with vehicles in order to establish the Korean database of exhausted gas from various engines. In the case of SRF, gasoline, and diesel, the outcome has been revealed as the average of carbon isotope -26.814‰, - 26.949‰, and -28.298‰ respectively. As a result, the carbon isotope of area located in the near plant might expect to be in the range from -26.814‰ to -25.446‰, and that in the urban might expect to be about -30‰.

Key Words

Stable isotope, Carbon isotope, Fluff-SRF, Tracking of air pollutant source, Particulate matter

성진호 Jin-ho Sung , 조수진 Su-jin Cho , 이은송 Eun-song Lee , 이주찬 Joo-chan Lee , 김정훈 Jeong-hun Kim , 엄남일 Nam-il Um , 김우일 Woo-il Kim , 김기헌 Ki-heon Kim , 서용칠 Yong-chil Seo

DOI:10.9786/kswm.2019.36.7.652

Abstract

This paper addresses the management of mercury released from anthropogenic sources in South Korea. Based on previous studies, mercury-contaminated waste from 2011 to 2030 was estimated. During that period, mercury release into anthropogenic sources increased from an estimated 54 to 88 tons. The source of the mercury was primarily nonferrous metal smelting facilities. The estimates did not include reuse of byproducts such as cement production facilities and sewage sludge incineration. Excluding those byproducts, mercury releases from anthropogenic sources increased from an estimated 41 to 71 tons during the same period. Mercury released from nonferrous metal smelting facilities was about 88% of South Korea. The generation of mercury-contaminated waste was calculated using mercury and the mercury byproducts. Mercury-contaminated waste from anthropogenic sources was estimated to increase from 11,700 to 12,800 thousand tons (from 2011 to 2030). The mercury-contaminated waste was released by fly ash from coal combustion part. The management of mercury releases and the treatment of sludge from nonferrous metal smelting facilities is important. In addition, the treatment of fly ash from coal combustion waste is important for reducing and managing mercurycontaminated waste.

Key Words

Mercury, Release, Contaminated waste, Distribution factor

이주찬 Joo-chan Lee , 성진호 Jin-ho Sung , 이은송 Eun-song Lee , 김정훈 Jeong-hun Kim , 조수진 Su-jin Jo , 서용칠 Yong-chil Seo

DOI:10.9786/kswm.2019.36.7.665

Abstract

The steel industry generally has been consuming a significant amount of raw materials and energy to manufacture steel. However, the discharge of various types of byproducts and waste were approximately 50%. In the case of iron manufacturing, many byproducts and wastes are generated from complicated production processes involving raw materials, rolled steel, and stainless steel. While the production of steel slag is increasing, the blast furnace and steel slag discharged from steel facilities are only partially recycled for use in low-value road aggregate and cement materials for reuse in the cement and iron facility processes. It is necessary to reduce the production of iron waste and thus reduce the cost of waste disposal through recycling while preventing environmental pollution. Furthermore, it is important to recycle steel slag produced in industrial activities and develop ways to extend recycling methods. In the previous study, the oxidation characteristics of elemental mercury were identified using steel slag. Previous research has found that mercury control efficiency is approximately 50% in domestic steel facilities and that mercury is oxidized by fly ash and steel oxide. In this study, experiments were performed at room temperature (100℃ and 200℃) for each air and syngas. The oxidation reaction of elemental mercury using was estimated using 1 mm, 2.36 mm, and 4.75 mm steel slag samples. Oxidation reactivity was approximately two times higher in the oxidation reaction at 100℃ and 200℃ than at room temperature. There was a slight variation in the oxidation reaction at 100℃ to 200℃. The level of oxidation reaction was not significant, regardless of the temperature and size of the samples. However, oxidation reactivity experienced the highest values under syngas conditions.

Key Words

Steel slag, Recycling, Elemental mercury, Oxidation

김기헌 Ki-heon Kim , 강준구 Jun-gu Kang , 이동진 Dong-jin Lee , 이원석 Won-seok Lee , 문희성 Hee-sung Moon

DOI:10.9786/kswm.2019.36.7.673

Abstract

This study was to use the basic data through the analysis of physical and chemical properties of produced dry feed in facilities that using raw materials from food waste. In addition, based on the standards of solid recovered fuel (SRF) and bio-SRF, we evaluated the potential use of recycling in thermochemical processes such as incineration plants, cement plants, and power plants that can recover energy. Results from food waste analyses of three components of dry feed showed moisture content of 4.9% (content range of 0.4 ~ 8.4%), combustible content of 79.9% (75.1 ~ 86.6%) and ash content of 15.2% (12.9-16.5%). These results satisfy the SRF standards of water content of less than 10% and an ash content of less than 20%. However, the ash content of 15% partially exceeded the bio-SRF standard. Results of the elemental analyses were established to be average percentages of carbon 44.1% (41.8 ~ 46.3%), hydrogen 3.7% (3.2 ~ 4.1%), nitrogen 6.4% (6.0 ~ 6.8%), sulfur 0.29% (0.26 ~ 0.31%), and chlorine 1.35% (1.18 ~ 1.74%). All results met the SRF standards, though the bio-SRF standard of chlorine of less than 0.5% was exceeded. The average biomass content was 94.4% across facilities, although some facilities did not meet the Bio-SRF standard. Analysis of low calorific value showed that the average of 3,928 kcal/kg (3,740 ~ 4,170 kcal/kg) fulfilled this SRF standard in all facilities. Effects of the external environment on dry feeds in long term storage (for at least 8 months) were analyzed. As a result of analysis moisture content and calorific value with increased over storage time, the difference between the two parameters was undistinguished. In addition, the impact of precipitation due to weak water proof cover significantly increased the overall water content of food waste.

Key Words

Food waste, Dry feed, Calorific value, SRF, Bio-SRF

백승기 Seung-ki Back , 성진호 Jin-ho Sung , 정법묵 Bup-mook Jeong , 장하나 Ha-na Jang , 이은송 Eun-song Lee , 조수진 Soo-jin Cho , 강연석 Yeon-suk Kang , 서용칠 Yong-chil Seo

DOI:10.9786/kswm.2019.36.7.683

Abstract

This study estimated the stability of mercury (Hg) compounds in coal combustion residuals (CCRs) from Hybrid Filter (HF) systems in coal power plants. The HF system, which was designed for the control of fine particulate matter, was found to have a performance to have a co-benefit effect by controlling mercury compounds in flue gas. The cascade impactor was used to measure the control efficiency of dust by particle size at the inlet and outlet of the HF system. Then, the particle size distribution of the HF fly ash was estimated by comparing the concentrations of the total suspended particles. The sequential extraction procedure consisting of five steps was applied to the CCRs: fly ash from the electrostatic precipitator and HF, and gypsum from the flue gas desulfurization. The behavior of Hg was affected by the development of air pollution control devices (APCDs), and as a result, we identified fly ash having a different form compared to previously reported data. The residual Hg fraction increased to a greater extent compared to the mobile Hg fraction in HF fly ash compared to ESP fly ash; the fraction estimated to be Hg⁰ and Hg⁰-amalgam decreased. FGD gypsum contained a higher ratio of the mobile Hg fraction than the fly ash collected from ESP and HF. Information on the stability of Hg compounds regarding developed APCDs needs to be considered for the recycling and disposal of CCRs.

Key Words

Fine particulate matter, Hybrid Filter, Co-benefit effect, Mercury, Stability

김희진 Hee-jin Kim , 김정훈 Jeong-hun Kim , 김종현 Jong-hyeon Kim , 박정민 Jung-min Park

DOI:10.9786/kswm.2019.36.7.693

Abstract

Recently, there has been growing interest in the emission characteristics and behavior of anthropogenic mercury compounds from emission sources. It is required to establish a standard for reliable mercury measurement methods. To address this necessity, this study has evaluated the applicability of the new measurement method, Continuous Emission Monitoring (US EPA 30A, CEM). In addition, the reliability evaluation was conducted through the Ontario Hydro Method (ASTM D6784, OHM) and Sorbent trap method (US EPA Method 30B). Monitoring for three months using CEM from municipal waste and hospital incinerators indicated that emission concentrations ranged from 5 to 20 μg/Sm³ with an average concentration of 10.48 μg/Sm³ and the maximum mercury concentration was about 150 μg/Sm³ in municipal incinerators. In the case of hospital waste incinerators, the variation of the mercury emission concentration was large, with an average of 16.74 μg/Sm³ and a maximum of 280 μg/Sm³. This may be due to unintentional waste intermittently fed into incinerators, and episodes associated with high concentrations of mercury emissions have been shown to be relatively short (several hours). No problems were encountered during sampling or analysis, and the reported data are believed to be representative of the stack conditions at the time of testing. As a result of the RATAs (Relative Accuracy Test Audits) by inter-mercury measurement methods for the municipal waste and the hospital waste incinerators, it was found that both facilities satisfied the RATAs by the proposed standard evaluation method. More measurements, including Hg sources, are to be carried out in the future to have a clear scenario of Hg emissions from the country and to be able to apply effective control measures.

Key Words

Mercury measuring method, CEM (Continuous Emission Monitoring), Sorbent trap, RATAs (Relative Accuracy Test Audits), Ontario Hydro Method (OHM)

장하나 Ha-na Jang , 이주형 Ju-hyung Lee , 김정훈 Jeong-hun Kim , 송금주 Geum-ju Song , 문영훈 Young-hun Moon , 서용칠 Yong-chil Seo

DOI:10.9786/kswm.2019.36.7.704

Abstract

With the trend towards more stringent regulations, Korea has investigated implementing US MACT (Maximum Available Control Technology) or BAT (Best Control Technology) to manage hazardous air pollutants (HAPs) from major emission sources. Sampling and analyses of hazardous air pollutants were performed at five municipal waste incinerators (MWIs) with different combustion capacities and air pollution control device configurations. The concentrations of particulate matter and heavy metals were controlled at efficiencies of 90 ~ 95% across the APCDs due to the installation of bag-filters with high efficiencies in all the MWIs examined. All MWI plants complied with the emission limit of NOx. In the tested facilities, selective catalytic reduction (SCR) was more efficient for NOx removal than selective non-catalytic reduction (SNCR). Benzene and its compounds and xylene were the main emitted substances among the volatile organic compounds (VOCs). A draft guideline of MACT was suggested based on US MACT regulations for MWIs, reviewing the existing Korean regulations, and sampling and analyzing the HAPs from operating facilities.

Key Words

Harzardous air pollutants, Maximum available control technology, Municipal solid waste, Nox, Volatile organic compound