• Title/Summary/Keyword: Thermal decomposition reactor

Search Result 101, Processing Time 0.02 seconds

Effect of Inlet Shape on Thermal Flow Characteristics for Waste Gas in a Thermal Decomposition Reactor of Scrubber System (반도체 폐가스 처리용 열분해반응기의 입구형상이 열유동 특성에 미치는 영향에 관한 수치해석 연구)

  • Yoon, Jonghyuk;Kim, Youngbae;Song, Hyungwoon
    • Applied Chemistry for Engineering
    • /
    • v.29 no.5
    • /
    • pp.510-518
    • /
    • 2018
  • Recently, lots of interests have been concentrated on the scrubber system that abates waste gases produced from semiconductor manufacturing processes. An effective design of the thermal decomposition reactor inside a scrubber system is significantly important since it is directly related to the removal performance of pollutants and overall stabilities. In the present study, a computational fluid dynamics (CFD) analysis was conducted to figure out the thermal and flow characteristics inside the reactor of wet scrubber. In order to verify the numerical method, the temperature at several monitoring points was compared to that of experimental results. Average error rates of 1.27~2.27% between both the results were achieved, and numerical results of the temperature distribution were in good agreement with the experimental data. By using the validated numerical method, the effect of the reactor geometry on the heat transfer rate was also taken into consideration. From the result, it was observed that the flow and temperature uniformity were significantly improved. Overall, our current study could provide useful information to identify the fluid behavior and thermal performance for various scrubber systems.

A Study on Thermal Decomposition Characteristics of exo-tetrahydrodicyclopentadiene with Variation of Flow Rate (유량 변화에 따른 exo-tetrahydrodicyclopentadiene의 열분해특성에 관한 연구)

  • Kang, Saetbyeol
    • Korean Chemical Engineering Research
    • /
    • v.57 no.6
    • /
    • pp.763-767
    • /
    • 2019
  • In this study, thermal decomposition characteristics of exo-tetrahydrodicyclopentadiene (exo-THDCP) composed with a single compound were analyzed by using a flow reactor. The experiments were carried out at $500^{\circ}C$, 50 bar and the products of each flow rate condition were analyzed by using a GC/MS. As a result, it was confirmed that exo-THDCP was decomposed mainly into cyclic compounds and a part was isomerized by heat. As the flow rate was increased, the kinds and ratio of compounds produced through the decomposition and isomerization were decreased. Also, the conversion rate of exo-THDCP and the amount of heat absorbed during the decomposition were also decreased. The compounds rapidly produced by decomposition were mainly formed through the radical form of 1-cyclopentylcyclopentene (1-CPCP) which is one of the intermediates that can be formed from exo-THDCP because it has the lowest activation energy of 42 kcal/mol.

The Kinetics of Radical Copolymerization and Thremal Decoposition of Poly(Styrene-co-2- Hydroxypropylacrylate) (Poly(Styrene-co-2-Hydroxypropylacrylate)의 라디칼 공중합 및 열분해 속도론)

  • Kim, Nam-Seok
    • Journal of the Korean Applied Science and Technology
    • /
    • v.26 no.2
    • /
    • pp.205-212
    • /
    • 2009
  • Solution copolymerization of Styrene(St.) with 2-Hydroxypropylacrylate(2-HPA) was carried out with Benzoylperoxide(BPO) as an initiator in toluene at $80^{\circ}C$ in a batch reactor. Reaction volume and reaction time were 0.3 liters, 8 hours respectively. The time to reach steady state was about the six time. The monomer reactivity ratios, $r_1$(St.) and $r_2$(2-HPA) were determined by both the Kelen-Tudos method and the Fineman-Ross method ; $r_1$(St.)=0.376(0.330), $r_2$(2-HPA)=0.408(0.778). The activation energy of thermal decomposition was in the range of $33{\sim}55kcal/mol$.

Removal of Styrene Using Different Types of Non-Thermal Plasma Reactors (저온플라즈마 반응기의 형태에 따른 스타이렌 분해 특성에 관한 연구)

  • Park, Jeong-Uk;Choi, Kum-Chan;Kim, Hyun-Ha;Ogata, Atsushi;Futamura, Shigeru
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.27 no.2
    • /
    • pp.215-223
    • /
    • 2005
  • Non-thermal plasma decomposition of gas-phase styrene was investigated in this study using three different types of plasma reactors; dielectric-barrier discharge (DBD) reactor, surface discharge (SD) reactor and plasma-driven catalyst (PDC) reactor packed with 2.0 wt% $Ag/TiO_2$ catalysts. The main parameters used for the comparative assessment of the plasma reactors include the decomposition efficiency, carbon balance, byproduct distribution, COx ($CO+CO_2$) selectivity and COx yield. The SD and the DBD reactors showed better conversion efficiency of styrene than that of the PDC reactor due to their larger capability in ozone formation. On the other hand, the PDC reactor showed better carbon balance, the yield and the selectivity of COx. The required specific input energies to achieve 100% carbon balance from the decomposition of 100 ppmv styrene using the plasma alone reactors and the PDC reactor were 420 J/L and 110 J/L, respectively. The major decomposition products in gas-phase were CO, $CO_2$ and HCOOH regardless of the types of plasma reactors. In the case of SD and DBD reactors, the $CO_2$ selectivity ranged in $39.5{\sim}60%$. The $CO_2$ selectivity in the PDC reactor was in range of $68.5{\sim}75.5%$.

Thermal Decompostion of Methane Using Catalyst in a Fluidized Bed Reactor (유동층반응기에서 촉매를 이용한 메탄 열분해)

  • Jang, Hyun-Tae;Lee, Ji-Yun;Cha, Wang-Seog
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.9 no.2
    • /
    • pp.487-492
    • /
    • 2008
  • In this paper, Thermocatalytic decomposition of methane in a fluidized bed reactor (FBR) was studied. The technical approach is based on a single-step decomposition of methane over carbon catalyst in air/water vapor free environment. The factors affecting methane decompostion catalyst activity in methane decomposition reactions were examined. The fluidization phenomena in a gas-fluidized bed of catalyst was determined by the analysis of pressure fluctuation properties, and the results were confirmed with characteristics of methane decomposition. The effect of parameters on the H2 yield was examined for methane decompostion. The decompstion rate was affected by the fluidization quality such as mobility, U-Umf, carbon attrition, elutriation and effectiveness density of fluidization gas.

Catalytic decomposition of ethane over carbon blacks (카본 블랙 촉매를 이용하는 에탄 분해에 관한 연구)

  • Kim, Mi-So;Lee, Sang-Yup;Yoon, Ki-June
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2007.11a
    • /
    • pp.93-96
    • /
    • 2007
  • Catalytic activities of color and conductive carbon blacks in ethane decomposition for $CO_2-free$ hydrogen production were investigated. The ethane decomposition was carried out in a conventional fixed bed reactor under atmospheric pressure at 973-1173 K for 2 hours. When the decomposition in the presence of carbon black was compared with the non-catalytic thermal decomposition, the former exhibited significantly higher ethane conversion, higher C(s) selectivity and lower ethylene selectivity with small increase of the methane selectivity, which resulted in higher hydrogen yield. This indicates that carbon black is catalytically effective for dehydrogenation of ethane as well as subsequent decomposition of ethylene. All the carbon blacks exhibited stable catalytic activity with time. In durability tests, fluffy N-330 and BP2000 maintained their activities for 36 hours.

  • PDF

Development of a drift-flux model based core thermal-hydraulics code for efficient high-fidelity multiphysics calculation

  • Lee, Jaejin;Facchini, Alberto;Joo, Han Gyu
    • Nuclear Engineering and Technology
    • /
    • v.51 no.6
    • /
    • pp.1487-1503
    • /
    • 2019
  • The methods and performance of a pin-level nuclear reactor core thermal-hydraulics (T/H) code ESCOT employing the drift-flux model are presented. This code aims at providing an accurate yet fast core thermal-hydraulics solution capability to high-fidelity multiphysics core analysis systems targeting massively parallel computing platforms. The four equation drift-flux model is adopted for two-phase calculations, and numerical solutions are obtained by applying the Finite Volume Method (FVM) and the Semi-Implicit Method for Pressure-Linked Equation (SIMPLE)-like algorithm in a staggered grid system. Constitutive models involving turbulent mixing, pressure drop, and vapor generation are employed to simulate key phenomena in subchannel-scale analyses. ESCOT is parallelized by a domain decomposition scheme that involves both radial and axial decomposition to enable highly parallelized execution. The ESCOT solutions are validated through the applications to various experiments which include CNEN $4{\times}4$, Weiss et al. two assemblies, PNNL $2{\times}6$, RPI $2{\times}2$ air-water, and PSBT covering single/two-phase and unheated/heated conditions. The parameters of interest for validation include various flow characteristics such as turbulent mixing, spacer grid pressure drop, cross-flow, reverse flow, buoyancy effect, void drift, and bubble generation. For all the validation tests, ESCOT shows good agreements with measured data in the extent comparable to those of other subchannel-scale codes: COBRA-TF, MATRA and/or CUPID. The execution performance is examined with a mini-sized whole core consisting of 89 fuel assemblies and for an OPR1000 core. It turns out that it is about 1.5 times faster than a subchannel code based on the two-fluid three field model and the axial domain decomposition scheme works as well as the radial one yielding a steady-state solution for the OPR1000 core within 30 s with 104 processors.

The Study of the Effects of Nonthermal Plasma-Photocatalyst combined Reactor on Hydrocarbon Decomposition and Reduction during Cold Start and Warm-up in a SI Engine (스파크 점화기관 냉간 시동시 플라즈마 광촉매 복합장치에 의한 탄화수소 화합물 저감에 관한 실험적 연구)

  • Lee, Taek-Heon;Chun, Kwang-Min;Chun, Bae-Hyeock;Shin, Young-Gy
    • 한국연소학회:학술대회논문집
    • /
    • 2001.11a
    • /
    • pp.169-178
    • /
    • 2001
  • Among the recent research ideas to reduce hydrocarbon emissions emitted from SI engines till light-off of catalyst since cold start are those exploiting non-thermal plasma technique and photo-catalyst that draws recent attention by virtue of its successful application to practical use to clean up the atmosphere using the feature of its relative independence on temperature. Based on the previous research results obtained with model exhaust gases using an experimental emissions reduction system that utilizes the non-thermal plasma and photo-catalyst technique, further investigation was conducted on a production N/A 1.5 liter DOHC engine during cold start to warm-up. For the effects of non-thermal plasma-photocatalyst combined reactor, 10% concentration reduction was achieved with the fuel component paraffins, and the large increase in non-fuel paraffinic components and acetylene concentrations were similar to those of base condition. However the absolute value was locally a bit higher than those of base condition since the products was made from the dissociation and decomposition of highly branched paraffins by plasma-photocatalyst reactor. Olefinic components were highly decomposed by about 75%, due to these excellent decompositions of olefins which have relatively high MIR values, and the SR value was 1.87 that is 30% reduction from that of base condition, then, the photochemical reactivity was lowered.

  • PDF

Recovery of Gallium from GaAs Scraps by Thermal Decomposition (GaAs Scrap으로부터 熱分解法에 의한 갈륨 回收)

  • Choi, Young-Yoon;Nam, Chul-Woo;Yu, Yeon-Tae;Kim, Wan-Young
    • Resources Recycling
    • /
    • v.14 no.2
    • /
    • pp.28-32
    • /
    • 2005
  • By using thermal decomposition method, the preliminary experiments for recovery of metallic Ga from GaAs scraps produced in the manufacturing of compound semiconductors were carried out in laboratory(200 g/batch) scales. From these results, decomposition appratus with packed tower was constructed in commercial scale(30 kg/batch). The decomposition rate of GaAs increased with raising decomposition temperature, but the yield of Ga decreased over 1000$^{\circ}C. As a result, the optimum decomposition temperature was 1000~1050$^{\circ}C when the pressure of decomposition reactor was 2~2.5${\times}10^{-2} mmHg, and the yield of Ga was about 89 wt.%. The commercial decomposition apparatus was designed with packed tower because the partial pressure of As in vapor state was not reduced even if the temperature of As vapor was decreased. The recovery yield of Ga from GaAs scraps in large scale experiment showed 99%.

Incineration for Demilitarization of Waste Cyclotol (회수 Cyclotol의 비군사화를 위한 소각공정)

  • Lee, Si-Hwang;Baek, Seung-Won;Moon, Il;Park, Jung-Su;Kim, Hyoun-Soo;Oh, Min
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.19 no.4
    • /
    • pp.545-550
    • /
    • 2016
  • Demilitarization involves the disposal and recovery of obsolete explosives or ammunition. Cyclotol has been used as a military explosive along with RDX and HMX. A limited number of processes exist for safe disposal due to their sensitivity to thermal shock. Rotary kilns are widely used for thermal decomposition in many countries due to cost effectiveness and simplicity compared with supercritical oxidation. Phase change as well as condensed phase reactions(CPRs) and gas phase reactions(GPRs) with rates described by the Arrhenius equation of cyclotol has been considered in this work. Changes in gas fraction, reaction rate and mass of explosives were predicted at 490, 505 and 575 K. A maximum temperature of 2062 K has been predicted within the reactor at an initial temperature of 575 K due to GPRs. From this research, Thermal decomposition in the rotary kiln is plausible for demilitarization.