송태협 Tae-hyeob Song , 박지선 Ji-sun Park , 이세현 Sea-hyun Lee , 윤상혁 Sang-hyuck Yoon

DOI:10.9786/kswm.2016.33.2.111

Abstract

Using of the ground granulated blast furnace slag as the substitutes of cement mixtures is increasing. This is used about 40% as the substitutes commercially but recently there are several tests used the maximum 80%. When used as the substitutes of cement mixtures which can improve the durability, the watertightness and the sulfate resistance but there is reduced the concrete quality due to early strength reduction and the drying shrinkage increase. Therefore it is very important to make the curing environment which helps early hydration activation vigorously. In this study, the hydrate characteristics replacing the maximum 80% of ordinary portland cement with blast furnace slag powder and using the alkali activator to increase early hydration activation were considered and analyzed by the XRD, TG-DTA, SEM, From these tests results, the use of the alkali activator had the increase of the calcium hydroxide according to ages and the reach time reduced about 1 min. and 9 min. for the first and second peak respectively. The effects on the hydrate characteristics of using the alkali activator were not significant.

Key Words

Slag powder, Hydrate, Cement, Hydro thermal reaction

오민아 Minah Oh , 조우리 Woori Cho , 정원덕 Won-duck Chung , 박성규 Seong-kyu Park , 이재영 Jai-young Lee

DOI:10.9786/kswm.2016.33.2.119

Abstract

The ocean dumping of organic waste as food waste has been prohibited since 2012 and so it is necessary to find alternative methods for its treatment and disposal. The purpose of this study was to treat food waste via hydrothermal carbonization (HTC) that has advantages such as no pre-treatment as drying feedstock and low energy consumption. Additionally, feasibility study for Bio-SRF (Solid Refused Fuel) was conducted to produce hydrochar via HTC. As results from quality standards experiments based on 「Solid Fuel Product Quality Testing Method in Korean」, the optimal condition of 220℃ as reaction temperature and 4 hr as reaction time have been selected. Since 2012, the ocean dumping of organic waste as food waste has been prohibited, it is necessary to replace its treatment and disposal. This study applied to treat of food waste via hydrothermal carbonization (HTC) which the method has advantages such as no pre-treatment as drying feedstock and low energy consumption. Moreover, feasibility study for Bio-SRF (Solid Refused Fuel) conducted to producted hydrochar via HTC. As a results from quality standards experiments based「Solid Fuel Product Quality Testing Method in Korean」, the optimal condition of 220℃ as reaction temperature and 4 hr as reaction time has been selected.

Key Words

Hydrochar, Bio-SRF, Food waste, Hydrothermal carbonization

김정은 Jeong-eun Kim , 김동현 Dong-hyun Kim , 정재칠 Jae-chil Jung , 송형운 Hyoung-woon Song , 육종묵 Jong-mook Yuk , 전오성 Oh-sung Jeun , 장석준 Seuk-jun Jang , 노영석 Young-seok Roh

DOI:10.9786/kswm.2016.33.2.129

Abstract

This study is to compose the optimized membrane module process system to selectively separate and treat toxic gas emitted from the semiconductor process. To optimize the operation of membrane module process system to treat toxic gas, the inlet toxic gas toward the membrane module shall have equal flux and equal pressure. Therefore, if the inlet flux on the membrane may be equalized only with the adjustment of pipe diameter and arrangement without installation of devices such as flowmeter at the junction between distributing pipe and separation membrane, the pipe composition of membrane module process system may be optimized to reduce the cost as well. Here, the inlet gas pressure toward the membrane module shall be above 3 bar, and thus in this study, the system was established for gas to be compressed with the compressor to stably maintain the pressure at the inlet of membrane module. Accordingly, the flow and pressure of gas within the pipe from the compressor to the membrane module were evaluated through the numerical analysis to optimize the diameter and arrangement of pipe - eventually to be reflected on the on-site design. Based on the result of flow analysis, the 5,000 LPM fluoride gas separation system to be applied to the actual semiconductor process was established, and to confirm the separation and return efficiency of NF₃, CF₄, and SF₆, in this study 1,000 ppm of highly concentrated NF₃, CF₄, and SF₆ were injected into the system to check the rate of separation and return. The system was continuously operated for 300 hours, and in case of SF₆ and CF₄, on average of 93% or higher return rate and concentration ratio of 1 were maintained, while in case of NF3, on average of 90% or higher return rate and concentration ratio of 1 were maintained. Therefore, it was confirmed that the fluoride gas separation system may be applied as a low-energy consumption high-efficiency system for the electronic industry.

Key Words

Permeance, Membrane, Separation, Electronics industry, Perfluorocompound gas

정원덕 Wonduck Chung , 오민아 Minah Oh , 조우리 Woori Cho , 박성규 Seong-kyu Park , 이재영 Jai-young Lee

DOI:10.9786/kswm.2016.33.2.137

Abstract

The amount of food waste is generated every year in Korea. Despite food waste contain a large amount of valuable organic resources, The rate of recycling is low because of high moisture contents and sodium. It proposed a solution to the problem is the Hydrothermal carbonization (HTC) technology. The Bio-char is produced by HTC allows to increase the recycling uses. The agents of heavy metal adsorption are mainly used with lime and activated carbon. However, these have difficulties such as low economical feasibility and solubility. This study focused on the application of the adsorbent. It is expected to have advantages in heavy metal waste water like Acid Mine Drainage (AMD) or industrial effluent. In this study, the adsorption capacity of bio-char was measured with the conditions of the time and the amount of bio-char inputs to remove in the artificial AMD. Artificial waste water 10 ppm and 100 ppm was prepared using Cu, Pb, Cd, As, and analyzed a batch-test to find the optimum condition. The experimental results showed The optimal blending ratios with activated bio-char and contaminated water were 1 : 20 for high concentration (100 ppm), 1 : 100 for low concentration (10 ppm). As the results, the absorption efficiency of the heavy metals, shows more than 99% except for arsenic.

Key Words

Bio-char, Chemical activation, Heavy metal, Adsorption, Adsorbent

유흥민 Heung-min Yoo , 손준익 Jun-ik Son , 권영현 Young-hyun Kwon , 백승기 Seung-ki Back , 정법묵 Bup-mook Jung , 김기헌 Ki-heon Kim

DOI:10.9786/kswm.2016.33.2.145

Abstract

In present study, the coffee residue was analyzed to finding out physicochemical characteristics and TG analysis that can simulate a pyrolytic kinetic, while comparing with that of chicken residue and food waste. The higher heating value (HHV) of coffee residue was 5,250 kcal/kg that is higher than that of wood pellet (4,300 kcal/kg), Additionally, it showed a good activation energy 72 kJ/mol which is similar with that of other biomass, such as saw dust, wood-chip and so on. It means that the coffee residue is meeting to standard for highest quality of wood pellet, and it would be used as a biomass in the future. However, it never become a fuel without main fuel, such as coal and wood, because its discharge amount is too little. Thus, it has to be applied to existing process, such as power plant which must to meet a RPS regulation. For this, physicochemical characteristics of various biomass have to be analyzed, while considering a discharge amount of them. Therefore, the research result would be provided to reclassification coffee residue to biomass from food wastes in the future.

Key Words

Coffee residue, Physicochemical characteristics, Activatin energy, Biomass, Pyrolytic kinetic

박태순 Tae Soon Park , 엄우형 Woo Hyung Eum

DOI:10.9786/kswm.2016.33.2.154

Abstract

This paper presents the performance of the concrete included the bio sulfur derived from the landfill and additives. The bio sulfur was obtained from the landfill site and derived the various chemical process. The bio sulfur is the liquid type and the results of initial compression tests show that the bio sulfur itself is not good enough to generate the compressive strength. The additives which are paper ash and desulfurization gypsum added to support and increase the compressive strength of the bio sulfur concrete. The resistance of chemical and sodium ability of the bio sulfur and additive concrete were evaluated using SEM and EDS analysis. The structure of the bio sulfur and additive concrete shows the dense micro particle and hard enough to resist the chemical and sodium intrusion.

Key Words

Bio sulfur, Landfill, Paper ash, Compressive strength

정희숙 Hee Suk Jung , 고동신 Dong Shin Ko , 송형운 Hyoung Woon Song

DOI:10.9786/kswm.2016.33.2.164

Abstract

Purpose of this study is the design of the optimal membrane plate in filter press which is one of the devices for improving the solid-liquid separation through the mechanical dewatering of sewage sludge. We tried to improve durability of the membrane plate and efficiency of the filtrate drainage through the flow and structural analysis. Characteristics of specific pressure were also evaluated according to the shape of the membrane plate.

Key Words

Structural analysis, Filter press, Membrane plate, Solid-liquid separation, Design optimization

이용운 Yong Woon Lee , 박진제 Jinje Park , 류창국 Changkook Ryu , 채태영 Taeyeong Chae , 양원 Won Yang , 박현주 Hyunjoo Park

DOI:10.9786/kswm.2016.33.2.171

Abstract

For material recovery of black carbon and pyrolysis oil, pyrolysis is considered as an alternative to combustion-based technologies for treatment of waste tire. This study investigated the heat transfer optimization in a pyrolysis reactor for waste tire chips with a capacity of 24 t/d. The reactor was required to have a larger heat transfer rate from hot gas to tire chips in the early stage of pyrolysis, whereas the rate in the later stage should be lower. This was to prevent thermal cracking of heavy compounds in the pyrolysis vapor and to improve the quality of black carbon. CFD was applied to analyze the flow and heat transfer in the complex geometry of the reactor for a total of nine design cases. It was found that modifications to control the distribution of gas flow rate along the reactor are more effective for the present reactor than adjusting the measures for heat transfer enhancement (such as fins). The ideal design improvement was to divide the reactor into two gas sections for a separate control of the flow rate, and to remove the fins of which its alignment perpendicular to the flow inhibits the hot gas from approaching the tube of tire chips.

Key Words

CFD, Black carbon, Heat transfer, Pyrolysis, Waste tire

손해준 Hae-jun Son , 이우근 Woo-keun Lee

DOI:10.9786/kswm.2016.33.2.179

Abstract

In this study, the leaching characteristics of magnesium from mine residue by acid leaching method was studied. First, It was confirmed the effect of the particle size. The particle size was selected 80 mesh in consideration of the leaching amount and recycling rate of Mg. And after, It was compared to the leaching characteristics of magnesium by H₂SO₄, HCl and HNO₃. Among them, leaching efficiency of H₂SO₄ was best. After the experiments were conducted with H₂SO₄. The effect of various parameters such as acid concentration, reaction temperature, and liquid/solid ratio on the leaching process were investigated. It was determined that the leaching amount of magnesium increased with reaction acid concentration, temperature, and liquid/solid ratio, and decreasing particle size. Maximum leaching amount of magnesium was obtained at the condition of particle size blow 80 mesh, temperature 80℃, 6 M H₂SO₄, 10/1 liquid/solid ratio, 6 h of reaction time and 180 rpm.

Key Words

Magnesium, Acid leaching, Mine residue, Sulfuric acid

최형진 Hyeong-jin Choi , 이승희 Seung-whee Rhee

DOI:10.9786/kswm.2016.33.2.184

Abstract

Since sewage sludge has low heating value as an energy source, it is desirable that sewage sludge is mixed with woody waste to enhance energy potential. Among thermal methods for waste to energy, carbonization process is used in this study. In order to estimate reaction kinetics for carbonization process using mixture of woody waste and sewage sludge, the content of sewage sludge is varied from 10 ~ 30% in mixture of woody waste and sewage sludge in carbonization process. Carbonization time is changed from 10 min to 50 min and carbonization temperature is varied from 250℃ to 350℃. The carbonization process for mixture of woody waste and sewage sludge was optimized at carbonization temperature of 300℃ for 20 min, 20% of sewage sludge content. As increased carbonization temperature, reaction rate constant, frequency factor and degree of carbonization were increased. As increased the content of sewage sludge, conversion, ash content and degree of carbonization were decreased. At optimal conditions for carbonization process, frequency factor and activation energy in Arrhenius equation can be decided by 3.61 × 10^-2 min^-1, 7,101.8 kcal/kmol respectively.

Key Words

Sewage sludge, Carbonization, Reaction kinetics, Conversion, Activation energy

김나랑 Na-rang Kim , 박수남 Soo-nam Park , 구재회 Jae-hoi Gu , 김형택 Hyung-taek Kim

DOI:10.9786/kswm.2016.33.2.192

Abstract

This paper was conducted experimental work to energy recovery and syngas production using a pilot scale fixed bed gasification process of solid waste. The temperature of gasifier bottom section was the highest at about 522 ~ 808℃. The syngas composition was contained CO 10.0 ~ 11.4%, H₂ 8.4 ~ 11.3%, CH₄ 3.7 ~ 3.9%, CnHm 3.3 ~ 4.3% with lower heating value 1,500 kcal/Nm³. About 68.8% of the waste and the air energy is converted to syngas. Approximately 8.4% is lost in heat of heat exchanger and cleaning process and about 0.8% of the heat energy is recycled into the gasifier in the form of preheated air. The electric power output rate was found to range 10.5 to 12.5 kW.

Key Words

Downdraft fixed-bed gasifier, Synthesis gas, Air gasification, Power generation, Energy recovery

안재홍 Jaehong Ahn , 주문솔 Munsol Ju , 오정익 Jeong-ik Oh , 김재영 Jae Young Kim

DOI:10.9786/kswm.2016.33.2.200

Abstract

The disposal of food waste has raised environmental concerns. The use of food waste disposers can be a convenient measure to manage household organic wastes. This device can be introduced to resolve the inconvenience of separating food wastes and implement the policy for converting food wastes into resources. However, the use of disposer has been prohibited in Korea unless the total solid recovery rate is greater than 80% (by dry wt.). Therefore, it is important to separate solid portions from disposer wastewater as much as possible to meet the standard. The objective of this study is to examine the control factors such as sieve size of screen, coagulation, RPM of centrifuge on solid-liquid separation. The result revealed that the use of sieve less than or equal to 0.3 mm could meet the total solid recovery rate of 80% (by dry wt.). Also, the coagulation filtrate recirculation using a coagulant, PAC, improved the solid recovery rate of 11.0% (by dry wt.) in using the sieve of 0.6 mm. This led to the total solid recovery rate of 79.3% (by dry wt.). Although RPM variation of centrifuge hardly influences the total solid recovery rate, when the separated solid residue is processed to compost or feedstock it is good because of low moisture content.

Key Words

Food waste disposer, TS recovery rate, Solid-liquid separation, Filtrate coagulation