• Title/Summary/Keyword: 발열 특성

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A Study on the Thermal Characteristics of Waste Organic Sludges Generated from the Industrial Complex -Paper and Beverage Manufacturing Industries- (산업단지에서 배출되는 폐 유기성 슬러지의 열적 특성 -제지업 및 음식료업을 중심으로-)

  • Shon, Byung-Hyun;Lee, Joo-Ho;Jung, Moon-Hun;Kim, Min-Choul;Ko, Ju-Hyun;Park, Hung-Suck;Lee, Gang-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.5
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    • pp.1359-1367
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    • 2008
  • We analyzed the physical and chemical properties such as proximate analysis, ultimate analysis, heating values, thermogravimetric analysis, and combustion test for the organic sludges generated from paper and beverage manufacturing industries in the industrial complex. The average water and combustible content of the organic sludges from paper and beverage manufacturing industries were 66.07% and 14.67%, 54.98% and 26.77%, respectively. From the ultimate analysis of the organic sludges, C, H, O, N, and S compositions were 21.75%, 3.42%, 32.70%, 0.63%, and 0.30%, respectively. For beverage manufacturing industries, C, H, O, N, and S compositions were 39.88%, 4.28%, 23.20%. 2.65%, and 0.35%, respectively. According to the results of investigating the lower heating values by Dulong's equation, 1 sludge(T company) was on the range of over 2,000 kcal/kg. This sludge could be directly applied to industries which try to use the energy by direct incineration. From the TGA test, the minimum combustion temperature of A company's sludge was about $700^{\circ}C$ for direct use for energy and that of 3 sludges(C, I, and T company) were at least over $800^{\circ}C$.

A Kinetic Study of Steam Gasification of Low Rank Coal, Wood Chip and Petroleum Coke (저등급 석탄, Wood Chip, Petroleum Coke의 수증기 가스화반응 Kinetics 연구)

  • Gong, Sujin;Zhu, Xueyan;Kim, Yangjin;Song, Byungho;Yang, Won;Moon, Woongsig;Byoun, Yoonseop
    • Korean Chemical Engineering Research
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    • v.48 no.1
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    • pp.80-87
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    • 2010
  • Lignite of low rank coal and petroleum coke of high sulfur content can be high potential energy sources for coal gasification process because of their plentiful supply. The kinetic study of steam gasification has been performed in an atmospheric thermobalance with wood chip, lignite, bituminous, anthracite, pet-coke. The effects of gasification temperature($600{\sim}850^{\circ}C$) and partial pressure of steam(30~90 kPa) on the gasification rate have been investigated. The modified volumetric reaction model was applied to the experimental data to describe the behavior of carbon conversion and to evaluate the needed kinetic parameters. Lignite and wood chip with high volatile content showed high average gasification rates comparing to other fuel and thus they might be proper fuel for gasification processes. The activation energies for wood chip, lignite, bituminous, anthracite, and pet-coke through Arrhenius plot were found to be 260.3, 167.9, 134.6, 82.2, 168.9 kJ/mol, respectively. The expression of apparent reaction rates for steam gasification of various chars have been proposed as basic information for the design of coal gasification processes.

The study on DC-link Film Capacitor in 3 Phase Inverter System for the Consideration of Frequency Response (3상 인버터 시스템에서 주파수 특성을 고려한 필름 콘덴서의 DC-link 적용 방법에 관한 연구)

  • Park, Hyun-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.117-122
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    • 2018
  • A large-capacity three-phase system air conditioner recently includes an inverter circuit to reduce power consumption. The inverter circuit uses a DC voltage that comes from DC-link power capacitor with the function of rectifying, which means AC voltage to DC voltage using a diode. An electrolytic capacitor is generally used to satisfy the voltage ripple and current ripple conditions of a DC-link power capacitor used for rectifying. Reducing the capacitance of the capacitor decreases the size, weight, and cost of the circuit. This paper proposes an algorithm to reduce the input ripple current by combining the minimum point estimation phase locked loop (PLL) phase control and the average voltage d axis current control technique. When this algorithm was used, the input ripple current decreased by almost 90%. The current ripple of the DC-link capacitor decreased due to the decrease in input ripple current. The capacitor capacity can be reduced but the electrolytic capacitor has a heat generation problem and life-time limitations because of its large equivalent series resistance (ESR). This paper proposes a method to select a film capacitor considering the current ripple at DC-link stage instead of an electrolytic capacitor. The capacitance was selected considering the voltage limitation, RMS (Root Mean Square) current capacity, and RMS current frequency analysis. A $1680{\mu}F$ electrolytic capacitor can be reduced to a $20{\mu}F$ film capacitor, which has the benefit of size, weight and cost. These results were verified by motor operation.

Experimental Study of Co-firing and Emission Characteristics Fueled by Sewage Sludge and Wood Pellet in Bubbling Fluidized Bed (기포 유동층 반응기를 이용한 하수슬러지 및 우드펠렛 혼소에 관한 연소 특성 분석 및 비교)

  • Lee, Youngjae;Kim, Jongmin;Kim, Donghee;Lee, Yongwoon
    • Clean Technology
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    • v.23 no.1
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    • pp.80-89
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    • 2017
  • The bubbling fluidized bed (BFB) reactor with a diameter of 0.1 m and a height of 1.2 m was used for experimental study of co-firing and emission characteristics fueled by sewage sludge (SS) and wood pellet (WP). The facility consists of a fluidized bed reactor, feeding system, cyclone, condenser and gas analyzer, The mean particle diameter and minimum fluidization velocity are $460{\mu}m$ and $0.21ms^{-1}$ respectively. SS produced from Korea and WP from Canada were examined. The various mixing ratios of WP were 20, 50, and 80% based on HHV. The equivalence ratio of 1.65, reactor temperature of $800^{\circ}C$, air flow rate of $100Lmin^{-1}$, and fluidization number of 4 were fixed in the BFB experiment. In TGA, the range of combustion temperature of SS was wider than that of WP. It represents that the combustibility of WP is higher than that of SS. The BFB reactor temperature was maintained between 800 and $900^{\circ}C$. CO emission of SS was high because of lower combustibility. $NO_X$ and $SO_X$ formation of SS were higher than that of WP since high nitrogen and sulfur contents of SS. CO, $NO_X$, and $SO_X$ formation were suppressed as the mixing ratio of WP was increased. The slagging and fouling tendencies show high in all test conditions.

Evaluation of the Deicing Performance and Concrete Structure Effect with Various Deicing Chemicals (제설제 종류에 따른 융빙성능 및 콘크리트에 미치는 영향 평가에 관한 연구)

  • Lee, Byung-Duck;Yun, Byung-Sung;Lee, Joo-Kwang;Chung, Young-Hwan
    • International Journal of Highway Engineering
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    • v.7 no.4 s.26
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    • pp.113-123
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    • 2005
  • In this study, calcium chloride$(CaCl_2)$, sodium chloride (NaCl), organic acids-containing deicer(NS 40, NS 100), mixed deicier$(NaCl\;70%+CaCl_2\;30%,\;NS\;40\;70%+CaCl_2\;30%,\;NaCl\;70%+NS\;40\;30%,\;NS\;40\;70%+NaCl\;30%)$ is investigated based on the laboratory test for deicing performance, freez-thaw resistance of concrete, and corrosion rate of metal. Test items for deicing performance were ice melting and ice penetration, freezing point depressions and eutectic point, pH, thermal properties for selected deicing chemicals as well as their compatibility with concrete and metal were experimentally investigated. As a test results, in case of the use chloride-containing deicier in area that concrete structures has subjected to freez-thaw reaction in winter season, it showed that mixed deicing chemicals with optimum ratio has desirable method than use one deicing chemicals when is consider to deicing performance and effects, corrosion of steel materials, and freez-thaw resistance of concrete. When use various deicing chemicals mixed, NS40(70%)+calcium chloride(30%) showed the best effective method.

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Synthesis of High-energy-density Fuel through Dimerization of Bicyclo[2.2.1]hepta-2,5-diene over Co/HY Catalyst (Co/HY 제올라이트 촉매상에서 Bicyclo[2.2.1]hepta-2,5-diene 이량화를 통한 고에너지밀도 연료 제조)

  • Kim, Jongjin;Shim, Beomseok;Lee, Gayoung;Han, Jeongsik;Jeon, Jong-Ki
    • Applied Chemistry for Engineering
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    • v.29 no.2
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    • pp.185-190
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    • 2018
  • The dimer of bicyclo [2.2.1] hepta-2,5-diene (norbornadiene) can be used as a high-energy-density fuel. The purpose of this study is to investigate the effect of Co loading on the acid properties of HY zeolite catalyst and the catalytic activity in norbornadiene dimerization. When the cobalt was loaded on the HY zeolite catalyst, the amount of acid sites did not change, but the acid strength weakened. This can be attributed to the decrease in $Br{\ddot{o}}nsted$ acid site and the increase in Lewis acid site. The norbornadiene conversion and yield of norbornadiene dimer over the Co/HY catalyst showed higher than those over the HY zeolite catalyst. The higher activity of the Co/HY catalyst can be ascribed to the higher amount of Lewis acid sites over the Co/HY catalyst. Density and calorific values of the norbornadiene dimer prepared by using the Co/HY catalyst agreed well with the known values in the literature. It was confirmed that the norbornadiene dimer prepared in this study can be used as a high-energy-density fuel.

Structural Charateristics of Silk Fibroin Gel on The Preparation Conditions (Silk Fibroin Gel의 제조조건에 따른 구조특성)

  • Lee, Kwang-Gill;Lee, Young-Woo;Yeo, Joo-Hong;Nam, Jin;Kweon, Hae-Young;Park, Young-Hwan
    • Journal of Sericultural and Entomological Science
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    • v.41 no.1
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    • pp.41-47
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    • 1999
  • Silk fibroin dissolved in highly concentrated calcium chloride and ethanol mixture aqueous solution turned into gel under suitable conditions. Preparation conditions and properties of gel were investigated as a function of parameters such as pH of solution, fibroin concentration, glycerol concentration and molecular weight. When pH of silk fibroin aqueous solution was near the isoelectronic point(pH 3.9~4.0), gelation occurred rapidly and strength of gel was stonger than that of pH-unadjusted due to electrostatic repulsion decrease between silk fibroin macromolecules. As concentration of silk fibroin and glycerol was higher, gelation occurred more rapid. FT Infra-red spectra of freeze-dried fibroin gel showed that gelation was derived by intermolecular anti-parallel ${\beta}$-sheet structure formation. In addition to, it was found that white-precipitate occurred instead of gelation when aqueous silk fibroin was treated by enzyme(flavouzyme), however, after flavouzyme-treated silk fibroin aqueous solution was centrifugated gelation occurred instantly. The results of differential scanning thermal analysis and infra-red spectroscopy showed that thermal stability and crystallinity of enzyme-hydrolyzed fibroin are superior to those of unhydrolyzed fibroin.

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Study for Characteristic of Frictional Heat Transfer in Rotating Brake System (회전을 고려한 브레이크 디스크의 마찰열전달 연구)

  • Nam, Jiwoo;Ryou, Hong Sun;Cho, Seong Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.817-822
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    • 2017
  • The braking system is one of the most important components in vehicles and machines. It must exert a reliable braking force when they are brought to a halt. Generally, frictional heat is generated by converting kinetic energy into heat energy through friction. As the kinetic energy is converted into heat energy, high temperature heat is generated which affects the mechanical behavior of the braking system. Frictional heat affects the thermal expansion and friction coefficient of the brake system. If the temperature is not controlled, the brake performance will be decreased. Therefore, it is important to predict and control the heat generation of the brake. Various numerical analysis studies have been carried out to predict the frictional heat, but they assumed the existence of boundary conditions in the numerical analysis to simulate the frictional heat, because the simulation of frictional heat is difficult and time consuming. The results were based on the assumption that the frictional heat is different from the actual temperature distribution in a rotating brake system. Therefore, the reliability of the cooling effect or thermal stress using the results of these studies is insufficient. In order to overcome these limitations and establish a simulation procedure to predict the frictional heat, this study directly simulates the frictional heat generation by using a thermal-structure coupling element. In this study, we analyzed the thermo-mechanical behavior of a brake model, in order to investigate the thermal characteristics of brake systems by using the Finite Element method (FEM). This study suggests the necessity to directly simulate the frictional heating and it is hoped that it can provide the necessary information for simulations.

Electrode bonding method and characteristic of high density rechargeable battery using induction heating system (유도 가열 접합 시스템을 이용한 대용량 이차전지 전극의 접합 방법 및 특성)

  • Kim, Eun-Min;Kim, Shin-Hyo;Hong, Won-Hee;Cho, Dae-Kweon
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.6
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    • pp.688-697
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    • 2014
  • In this study, electrode bonding technology needed for high density of rechargeable battery is studied, which is recently researched for electric vehicle, the small leisure vessel. For the alternative overcoming the limit of stacking amount able to be stacked by conventional ultrasonic welding, the low temperature bonding method, eligible for minimum of degeneration of chemical activator on the electrode surface which is generated by thermal effect as well as the increase of conductivity and tension strength caused by electrode bonding using filler metal, not using conventional direct heating on the electrode material method, is studied. Specifically to say, recently used more generally the ultrasonic welding and spot welding method are not usable for satisfying stable electric conductivity and bonding strength when much electrode is stacking bonded. If the electrical power is unreasonably increased for the welding, due to the effect of welding temperature, deformation of electrode and activating material degeneration are caused, and after the last packaging, decline of electrical output and generating heat cause to reduce stability of battery. Therefore, in this study, induction heating system bonding method using high frequency heating and differentiated electrode method using filler metal pre-treatment of hot dipping are introduced.

Properties of Hydration Heat of High-Strength Concrete and Reduction Strategy for Heat Production (고강도 콘크리트의 수화열 특성 및 발열 저감대책에 관한 연구)

  • Jaung, Jae-Dong;Cho, Hyun-Dae;Park, Seung-Wan
    • Journal of the Korea Institute of Building Construction
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    • v.12 no.2
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    • pp.203-210
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    • 2012
  • Recently, the interest and demand for large-scale buildings and skyscrapers have been on the rise, and the performance of concrete is an area of high priority. Securing 'mass concrete and high strength concrete' is very important as a key construction technology. For high strength concrete, the high heat of hydration takes place inside the concrete because of the vitality of hydration in cement due to the large amount of powder, and leads to problems such as an increase of thermal stress due to the temperature difference with the outside, which results in cracks and slump loss. For this reason, measures to solve these problems are needed. This study aims to reduce the hydration heat of high strength concrete to control the hydration heat of mass concrete and high strength concrete, by replacing the type of admixture, The purpose of this study is to control the hydration heat of high strength concrete and mass concrete. Our idea for this purpose is to apply not only the types and contents of admixture but also incorporation mixing water to ice-flake. As a result of the test, the use of blast furnace slag and fly ash as admixture, and the use of ice-flake as mixing water can improve the liquidity of concrete and reduce slump loss. Significantly dropping the maximum temperature will contribute greatly to reducing cracks due to hydration heat in mass concrete and high strength concrete, and improve quality.