• Korean Chemical Engineering Research
• /
• 제47권3호
• /
• pp.337-343
• /
• 2009

선택적 고체순환을 위한 신개념 2탑 유동층 공정에 적용하기 위해 고체분리기와 고체순환시스템을 개발하였다. 고체분리기에 의한 고체분리속도는 고체분사노즐의 유속, 고체층 높이, 고체분사노즐의 직경이 증가함에 따라 증가하였으며 유동화 속도의 영향은 크지 않았다. 본 연구에서 개발한 고체분리기를 이용하여 굵은입자($212{\sim}300{\mu}m$)와 고운입자($63{\sim}106{\mu}m$)의 분리가 가능하였으며 고체분리속도는 66~453 g/min의 범위를 나타내었다. 고체순환시스템의 고체순환속도는 고체분사노즐의 유속, 고체층 높이, 고체유입구멍의 개수가 증가함에 따라 증가하였으며 유동화 속도의 영향은 크지 않았다. 본 연구에서 개발한 고체순환시스템을 이용하여 고운입자의 순환이 가능하였으며 고체순환속도는 65~390 g/min의 범위를 나타내었다. 본 연구에서 개발된 고체분리기와 고체순환시스템을 적용하여 선택적 고체순환이 가능한 2탑 유동층 공정을 구성하였으며 장기연속운전 가능성을 확인하기 위해 약 20시간까지 고체분리-순환 장기연속운전을 실증하였다. 두 유동층의 압력강하 값과 고체분리속도가 안정적으로 유지되어 고체순환이 원활하게 유지되는 것을 확인하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
• /
• pp.393-397
• /
• 2001

The innovatory process, that is the direct separation and recovery of the iron and zinc metals contained in the high temperature exhaust gas generated from the electric arc furnace fer the inn scrap melting and/or the dust treatment, has been proposed. This proposed process consists of the moving coke bed filter that is directly connected to the electric furnace, and the following heavy metal condenser. The exhaust gas passes through the filter and the condenser right after exhausting from the electric furnace. The moving coke bed filter is being controlled at about 1000℃ and collects iron and slag components contained in the high temperature exhaust gas. Heavy metals such as zinc and lead pass through the filter as vapor. Based on the thermodynamic considerations, the iron oxide and the zinc oxide are reduced in the filter. The solution loss reaction rate is comparatively low at about 1000℃ in the coke bed filter by the analysis using the mathematical simulation model. The heavy metal condenser is installed in the position after the coke bed filter, and rapidly cools the gas from about 1000℃ to 450℃ by a full of the cooling medium like the solid ceramic ball in addition to the cooling from the wall. The zinc and lead vapor condense and separate f개m the gas in a liquid state. The investigation of the characteristics of the exhaust gas of the commercial electric arc furnace, the fundamental experiments of the laboratory scale and the bench scale ensured the formation of this proposed process. A small-scale pilot plant examination is carrying out at present to confirm the formation of the process. It is certain that the dust generation of the electric arc furnace is extremely decreased, and it can save the energy consumption of usual dust treatment processes by the realization of this process.

• Advances in environmental research
• /
• 제3권3호
• /
• pp.231-251
• /
• 2014

The present study examines the phosphate adsorption potential and behavior of mixture of Ground Burnt Patties (GBP), a solid waste generated from cooking fuel used in earthen stoves and Red Soil (RS), a natural substance in fixed bed column mode operation. The characterization of adsorbent was done by Proton Induced X-ray Emission (PIXE), and Proton Induced ${\gamma}$-ray Emission (PIGE) methods. The FTIR spectroscopy of spent adsorbent reveals the presence of absorbance peak at $1127cm^{-1}$ which appears due to P = O stretching, thus confirming phosphate adsorption. The effects of bed height (10, 15 and 20 cm), flow rate (2.5, 5 and 7.5 mL/min) and initial phosphate concentration (5 and 15 mg/L) on breakthrough curves were explored. Both the breakthrough and exhaustion time increased with increase in bed depth, decrease in flow rate and influent concentration. Thomas model, Yoon-Nelson model and Modified Dose Response model were used to fit the column adsorption data using nonlinear regression analysis while Bed Depth Service Time model followed linear regression analysis under different experimental condition to evaluate model parameters that are useful in scale up of the process. The values of correlation coefficient ($R^2$) and the Sum of Square Error (SSE) revealed the Modified Dose Response model as the best fitted model to the experimental data. The adsorbent mixture responded effectively to the desorption and reusability experiment. The results of this finding advocated that mixture of GBP and RS can be used as a low cost, highly efficient adsorbent for phosphate removal from aqueous solution.

• Carbon letters
• /
• 제7권3호
• /
• pp.180-187
• /
• 2006

The treatment of piggery wastes was carried out at pilot scale using a multilayered metal-activated carbon system followed by carbon bed filtration. The physicochemical properties were obtained from treated samples with aqueous solutions containing metallic ions such as $Ag^+$, $Cu^{2+}$, $Na^+$, $K^+$ and $Mn^{2+}$, which main obsevations are subjected to inspect surface properties, color removal properties by Uv/Vis and EDX. Multilayered metal-activated carbons were contacted with waste water to investigation of the simultaneous catalytic effect for the COD, BOD, T-N and T-P removal. The removal results for the piggery waste using multilayered metal-activated carbon bed was achieved the satisfactory removal performance under permitted values of Ministry of Environment of Korea. The high efficiency of the multilayered metal-activated carbon bed was determined by the performance of this material for trapping, catalytic effect and adsorption of organic solid particles.

• Food Science and Biotechnology
• /
• 제18권5호
• /
• pp.1071-1075
• /
• 2009

Allyl isothiocyanate (AI), a volatile compound of mustard, has excellent antimicrobial effects, but its volatility hinders its wide usage as an ingredient of food products. Microencapsulation technique, therefore, was applied for delaying the release time of AI. For delaying the release time of AI, the mustard powder, which contained AI, was microencapsulated with 5% modified starch by using fluidized bed processing. The efficiency of the controlled release of AI at various pH was analyzed by the head space (HS) analysis and solid phase microextraction (SPME) method using gas chromatography (GC). Also, modified starch encapsulated powder was added into kimchi for applying in food industry. As the result, the release time of AI was delayed by microencapsulation with modified starch and the higher pH could be the faster release of AI. Also, the period until the pH values and total acidity of kimchi reached up to 4.5 and 0.6%, which give its malsour taste, was extended by microencapsulation. These results showed that modified starch encapsulated powder could prolong the preservation in food system.

• 한국안전학회지
• /
• 제14권1호
• /
• pp.78-85
• /
• 1999

The removal characteristics of H$_2$S from IGCC process over the natural manganese ore(NMO) containing several metal oxides($MnO_x$ : 51.85%, $FeO_y$ : 3.86%, CaO : 0.11%) were carried out in a batch type fluidized bed reactor(I.D.=40mm, height=0.8m). The $H_2S$ breakthrough curves were obtained as a function of temperature, initial gas velocity, initial gas concentration, and aspect ratio. The effect of particle size ratio and particle mixing fraction on $H_2S$ removal were investigated with binary system of different particle size. From this study, the adsorption capacity of $H_2S$ increased with temperature but decreased with excess gas velocity. The breakthrough time for $H_2S$ is reduced as the gas velocity is increased which leaded to gas by-passing and gas-solid contacting in a fluidized bed reactor. The results of the binary particle system with different size in batch experimental could predict to improve the behavior of continuous process of $H_2S$ removal efficiency. The natural manganese ore could be considered as potential sorbent in $H_2S$ removal.

• Journal of Industrial and Engineering Chemistry
• /
• 제67권
• /
• pp.219-230
• /
• 2018

The present study examined a moving bed biofilm reactor (MBBR) bioreactor on a laboratory scale for simultaneous removal of atrazine, organic carbon, and nutrients from wastewater. The maximum removal efficiency of atrazine, chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN) were 83.57%, 90.36%, 90.74% and 87.93 respectively. Increasing salinity up to 40 g/L NaCl in influent flow could inhibit atrazine biodegradation process strongly in the MBBR reactor.Results showed that MBBR is so suitable process for efficiently biodegrading of atrazine and nitrogen removal process was based on the simultaneous nitrification-denitrification (SND) process.

• Nuclear Engineering and Technology
• /
• 제56권3호
• /
• pp.959-965
• /
• 2024

The High Temperature Test Unit (HTTU) was an experimental set-up to conduct separate and integral effects tests of the Pebble Bed Modular Reactor (PBMR) core. The annular core consisted of a randomly packed bed of uniform spheres. Natural convection tests using both nitrogen and helium, and forced convection tests using nitrogen, were conducted. The maximum material temperature achieved during forced convection testing was 1200 ℃. This paper presents the numerical analysis of the flow and temperature distribution for a forced convection test using 3D CFD as well as a 1D systems-CFD computer code. Several modelling approaches are possible, ranging from a fully explicit to a semi-implicit method that relies on correlations of their associated phenomena. For the comparison between codes, the analysis was performed using a porous media approach, where the conduction and radiative heat transfer were lumped together as an effective thermal conductivity and the convective heat transfer was correlated between the solid and gas phases. The results from both codes were validated against the experimental measurements. Favourable results were obtained, in particular by the systems-CFD code with minimal computational and time requirements.

• Korean Chemical Engineering Research
• /
• 제60권4호
• /
• pp.535-543
• /
• 2022

실리콘 카바이드 입자(평균 입도 123 ㎛)의 유동층 태양열 흡열기의 성능 및 효율에 영향을 미치는 입자 거동 해석을 위해 MP-PIC 모델을 이용하여 전산모사를 수행하였고, 기존 실험결과와의 비교를 통해 검증하였다. 특히, 본 연구에서는 실험적으로 접근하기 어려운 유동층 표면 부근에서의 거동을 모사함으로써 흡열 성능과 입자 거동과의 상호 영향을 분석하였다. CPFD 모사결과는 입자층 및 프리보드에서의 평균 고체체류량과 압력요동 등 수력학적 특성 실험결과를 잘 예측하였다. 입자 흡열기에서 1차적으로 태양열 에너지를 흡수하여 층 내부로 전달하는 층 표면 부근에서의 국부 고체체류량은 입자층 내 기포거동에 따라 중심부에서 상대적으로 낮은 값을 나타내는 불균일 분포를 나타내었다. 프리보드 영역에서 국부 고체체류량은 기체속도가 증가할수록 축방향과 각 높이에서의 횡방향에서 불균일성이 증가하였고, 이는 입자 흡열기의 프리보드 영역 내 비산된 입자에 의해 반사된 태양광 에너지 손실과 연관된 압력강하 상대표준편차 증가의 원인임을 나타내었다. 입자 흡열기 내 기체속도 증가에 따른 국부적인 기체 및 입자 속도의 변화에 대한 고찰을 통해, 유동층 내 국부적인 입자거동 특성은 Geldart B 입자 물성과 관련된 입자층 내 기포 거동과 밀접하게 연관됨을 확인하였다. 유동층 입자 흡열기의 성능 척도인 일사량 당 유동기체의 출입구 온도차(∆T/I_DNI)는 입자 층 표면 및 표면 상부 프리보드 영역 내 압력요동 RSD와 상관관계가 매우 높음을 확인하였고, 이 결과는 흡열기 성능 개선에 활용할 수 있을 것으로 판단되었다.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
• /
• pp.165-166
• /
• 2014

The application of particle reaction model in the packed bed process modeling is discussed for iron ore pellet induration process. Combustion of coke breeze in the pellet is estimated by using shrinking unreacted-core model and grain model in which the progress of chemical reaction is described in different concepts. Under the identical inlet gas and solid conditions, the calculation using shrinking core model showed deviated results in terms of temperature profile and conversion fraction, which may imply the significance of selecting proper particle reaction model in consideration of particle characteristics and process operation conditions.