• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.363-363
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• 2011

열분해 반응기 내에서 실리콘 필름을 성장시키는 것은 반도체/디스플레이, 태양전지, 신소재 등 다양한 분야에서 중요한 공정이다. 더욱이 반도체 소자 선폭이 줄어들면서 나노입자의 오염 제어가 더불어 중요해지고 있다. 생산 공정 기술의 집적화에 따라 패턴 사이 거리가 작아지고, 이에 불과 수 십 나노미터크기의 오염입자에 의해서 패턴불량이 발생하고 생산수율을 감소시킨다. 일반적으로 반도체 공정 중 발생한 오염입자는 반응기 내의 가스가 물리/화학적 공정에 의해 핵생성(nucleation)이 일어나 핵(nuclei)이 생성되고, 이 때 표면반응 및 응집(coagulation)에 의해 성장하게 된다. 이에 본 연구에서는 열분해 반응기 내에서 사일렌(SiH4) 가스를 열분해하여 발생되는 실리콘 오염입자의 핵생성과 성장 모델을 정립하고, 생성된 오염입자의 거동과 전달 현상을 이론적으로 고찰하였다. 열분해 반응기와 같은 기상공정(Gas to particle conversion)에서 오염입자가 생성될 때, 그 성질과 크기 등에 물리/화학적 영향을 주는 요소는 전구체/이송기체의 농도 및 유량, 작동 압력, 작동 온도와 반응기 고유 특성 등이 있다. 수치해석의 정당성과 빠른 계산을 위해 단순화시킨 0D 모델인 Batch 반응기와 1D모델인 plug flow 반응기 등에서 SiH4 가스의 열분해 과정시 생성되는 Si cluster를 상용코드인 CHEMKIN 4.1.1을 이용하여 계산하였으며, 2D모델인 Shear flow 반응기로 확장시켜 Si 오염입자가 생성특성을 연구하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.22-25
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• 2005

The thermal degradation of carbon/phenolic composite have been studied at high temperature by using thermogravimetric (TGA). A heating .ate of 5, 10, 15, 30 and $50^{\circ}C/min$ was used for the determination of thermal decomposition parameters of composite materials at high-temperature service. It has been shown that as the heating rates is increased, the peak decomposition rates are occur at higher temperature. Based on results of thermogravimetric analysis, the pyrolysis process is analyzed and physical and mathematical models for the process are proposed. The thermal analysis also has been conducted using transient heat conduction and the in-depth temperature distribution and the density profile were evaluated along the solid rocket nozzle. As a future effort the thermal decomposition parameter determined in this investigation will be used as input to thermal and mechanical analysis when subjected to solid rocket propulsion environment.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.35-41
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• 2001

Lignin model compounds I-lV were pyrolyzed at 315$^{\circ}C$. The mixture compounds pyrolized were analyzed by GC-MS spectrometry. The results were summarized as follows : 1. From the pyrolysis of lignin model compound I and II, 0.45mo1 of guaiacol, 0.5mol of dimethoxyphenol(DMP), and 0.12 and 0.23mo1 of dimethoxyacetonphenone(DMAP) were produced respectively. 2. In the pyrolysis of lignin model compound III and IV, 0.26mol of guaiacol, 0.30mo1 of DMP, and 0.09 and 0.15mo1 of trimethoxyaretonphenone(TMAP) were produced respectively 3. Pyrolysis mechanism of lignin model compounds are dehydrated at first, and $\beta$-04 linkage cleavaged, and then guaiacol, DMP, DMAP and TMAP were produced. The above results show that lignin model compound I and II produce more aromatic compounds than lignin model compound III and IV. This is reason that veratryl unit structures may pyrolize easier than trimethoxyphenol unit structures. The closer research is proceeding.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.76.2-76.2
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• 2011

석탄의 탄종별 열분해 생성물은 석탄가스화기의 뮬레이션 기법의 첫 번째 단계이며 이러한 탄종별 생성물 예측은 가스화기의 성능, 즉 가스화기 출구 가스조성, 탄소전환율, 냉가스 전환율등을 예측하는데 있어 가장 기본적이고 중요한 절차이다. 본 논문에서는 석탄가스화기내 열분해 과정을 모사할 수 있도록 석탄 성상과 가스화기 운전압력에 따라 탄종별 고온고압 열분해시의 생성물을 정량적으로 계산하는 방법을 제시하였다. Merrick(1983)의 방법을 기반으로 석탄의 성상(공업/원소분석치), 가스화기 운전압력과 몇가지 상관관계식으로부터 고온고압하 열분해 생성물을 계산하는 방법이며 이를 프로그램화하여 가스화기 시뮬레이터용 모듈로 구성할 수 있도록 하였다. 또한, 국내 수입 5개 탄종에 대하여 열분해 생성물의 조성을 구하였으며 이를 상용 열분해모델의 결과와 서로 비교하였다. 열분해 생성물 조성의 분포는 다른 상용 프로그램 결과와 부합하였으며 생성물의 발열량도 원탄의 발열량과 적합한 결과를 보여주었다.

• Resources Recycling
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• v.23 no.6
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• pp.47-53
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• 2014

Effective treatment and energy conversion technologies are necessary due to the ban of the dumping of organic waste including the sewage sludge. In this study, the kinetics of pyrolysis and combustion were derived in a TGA and thermobalance reactor, which is essential for thermal conversion of sewage sludge to energy. Three steps are shown for the pyrolysis in TGA and the different pre-exponential factors and activation energies are derived depending on the temperature range. Three models of gassolid reaction were applied to the reaction kinetics analysis for the combustion of sewage sludge char and shrinking core model was an appropriated model. Apparent activation energy and pre-exponential factor were evaluated and the effect of oxygen partial pressure was examined.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.349-356
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• 2020

The heat release rate (HRR) and fire growth rate of fire for the solid combustibles consisting of multi-materials was measured through the ISO 9705 room corner test, and the computational analysis in a closed compartment was performed to simulate a fire using the heat release rate prediction model provided by a Fire Dynamics Simulator (FDS). The method of predicting the heat release rate provided by the FDS was divided into a simple model and a pyrolysis model. Each model was applied and computational analysis was performed under the same conditions. As the solid combustible consisting of multi-materials, a cinema chair composed mostly of PU foam, PP, and steel was selected. The simple model was over-predicted compared to the predicted heat release rate and fire growth rate using the pyrolysis model in a closed compartment.

• Journal of Energy Engineering
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• v.18 no.1
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• pp.9-16
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• 2009

The experimental work has been carried out for the study of pyrolysis and char-air reaction of five coals used in Y power station in Korea. For five coals, the characteristics of pyrolyis and char reaction have been investigated with TGA, and their kinetic parameters were obtained and compared each other. The order of pyrolysis rate for five coals were as follows : Peabody, Flame, MIP, Indominco, Elk valley. The behavior of char - air reaction for five coal chars have been successfully described by the grain model. The rate of char-air reaction gave the maximum value for Flame coal char, on the while Elk valley coal char had the minimum value. For the reaction temperature over 1,000K, Flame coal char - air reaction was very fast compared with other coal chars.

• Fire Science and Engineering
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• v.30 no.1
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• pp.31-36
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• 2016

This study investigates the characteristics of thermal decomposition of an epoxy-based intumescent paint using thermogravimetric analysis (TGA) and numerical simulation. A mathematical and numerical model is introduced to describe mass loss profiles of the epoxy-based intumescent coating induced by the thermal decomposition process. The decomposition scheme covers a range of complexity by employing simplified 4-step sequential reactions to describe the simultaneous thermal decomposition processes. The reaction rates are expressed by the Arrhenius law, and reaction parameters are optimized to fit the degradation behavior seen during thermogravimetric (TG) experiments. The experimental results show a major 2-step degradation under nitrogen and a 3-step degradation in an air environment. The experiment also shows that oxygen takes part in the stabilization of the intumescent coating between 200 and $500^{\circ}C$. The simulation results show that the proposed model effectively predicts the experimental mass loss as a function of time except for temperatures above $800^{\circ}C$, which were intentionally not included in the model. The maximum error in the simulation was less than 3%.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.907-918
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• 2000

The pyrolysis characteristics of celluloses and plastics, which are the principal materials contributing to the municipal solid wastes(MSWs), was investigated with a thermal gravimetric analysis reaction system. The experiments were carried out in a nitrogen atmosphere in the temperature range of 400~900K at various experimental conditions. Also, a modified pyrolysis model for compressed MSWs has been proposed. Varing the heating rate to 20, 30, 40K/min, reaction orders of MSWs' main component were around 1.1~1.9, activation energies were 117~166kJ/mol for celluloses and 187~239kJ/mol for plastics. Char yield was proportional to the heating rate, particle size, and compressed ratio. The model proposed in this study, which is applying Arrhenius equation and thermodynamics, is closer to the experimental results than the conventional model.

• Fire Science and Engineering
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• v.31 no.3
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• pp.41-48
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• 2017

In order to investigate the influence of changes in the thermal properties of solid combustibles on thermal decomposition, a series of solid pyrolysis experiments were performed using a cone calorimeter specified in KS F ISO 5660-1. In the present study, Poly Methyl Methacrylate (PMMA) which does not produce Char during pyrolysis process was used as solid fuel. Results obtained from cone calorimeter experiments were compared to ones obtained from numerical analysis of Fire Dynamics Simulator (FDS) 1D pyrolysis model adopted with thermal properties of solid fuel as input parameters. Comparisons between experimentally calculated and model-predicted mass loss rate were then made to elucidate the effect of changes in the thermal properties on pyrolysis of PMMA.