• Nuclear Engineering and Technology
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• 제44권1호
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• pp.21-32
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• 2012

Fluorinated compounds mainly used in the semiconductor industry are potent greenhouse gases. Recently, thermal plasma gas scrubbers have been gradually replacing conventional burn-wet type gas scrubbers which are based on the combustion of fossil fuels because high conversion efficiency and control of byproduct generation are achievable in chemically reactive high temperature thermal plasma. Chemical equilibrium composition at high temperature and numerical analysis on a complex thermal flow in the thermal plasma decomposition system are used to predict the process of thermal decomposition of fluorinated gas. In order to increase economic feasibility of the thermal plasma decomposition process, increase of thermal efficiency of the plasma torch and enhancement of gas mixing between the thermal plasma jet and waste gas are discussed. In addition, noble thermal plasma systems to be applied in the thermal plasma gas treatment are introduced in the present paper.

• 대한기계학회논문집
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• 제19권9호
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• pp.2353-2364
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• 1995

The ignition phenomena of a solid fuel plate of polymethyl-methacrylate(PMMA), which is vertically positioned and exposed to a thermal radiation source, is numerically studied here. A two-dimensional transient model includes such various aspects as thermal decomposition of PMMA, gas phase radiation absorption, gas phase chemical reaction and air entrainment by natural convection. Whereas the previous studies considers the problem approximately in a one-dimensional form by neglecting the natural convection, the present model takes account of the two-dimensional effect of radiation and air entrainment. The inert heating of the solid fuel is also taken into consideration. Radiative heat transfer is incorporated by th Discrete Ordinates Method(DOM) with the absorption coefficient evaluated using gas species concentration. The thermal history of the solid fuel plate shows a good agreement compared with experimental results. Despite of induced natural convective flow that induces heat loss from the fuel surface, the locally absorbed radiant energy, which is converted to the internal energy, is found to play an important role in the onset of gas phase ignition. The ignition is considered to occur when the rate of variation of gas phase reaction rate reaches its maximum value. Once the ignition takes place, the flame propagates downward.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.658-661
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• 2007

KIER have been developing high-temperature solar technology, especially the solar thermal power generation system, since the early of 1990s. In 1994, the first research on high temperature solar technology started with PTC technology. At the moment the most advanced 10kW dish system is under demonstration for 10kW solar thermal power generation. Test results showed about 19.2% solar to electricity average efficiency. Another research activities of KIER is hybrid power generation. For hybridization, solar and LFG(landfill gas) are used. Another hybrid solar system is with solar chemical reaction. In this system, power unit is gas turbine, and the heat content of fuel(like natual gas) is upgraded by solar energy through chemical reaction. The latest project on solar thermal power generation is for 1 MW power tower system. This is the Korea-China Joint project.

• 한국산업융합학회 논문집
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• 제6권4호
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• pp.269-275
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• 2003

A non-thermal plasma process combined with $Cr_2O_3/TiO_2$ catalyst was applied to the decomposition of trichloroethylene (TCE). A dielectric barrier discharge reactor operated with AC high voltage was used as the non-thermal plasma reactor. The effects of reaction temperature and input power on the decomposition of TCE and the formation of byproducts including HCl, $Cl_2$, CO, NO, $NO_2$ and $O_3$ were examined. At an identical input power, the increase in the reaction temperature from 373 K to 473 K decreased the decomposition of TCE in the plasma reactor. The presence of the catalyst downstream the plasma reactor not only enhanced the decomposition of TCE but also affected the distribution of byproducts, significantly. However, synergistic effect as a result of the combination of non-thermal plasma with catalyst was not observed, i.e., the TCE decomposition efficiency in this plasma-catalyst combination system was almost similar to the sum of those obtained with each process.

• International Journal of Safety
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• 제9권1호
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• pp.6-11
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• 2010

Thermal analysis, heating test on gram scale and simulation of exothermic behavior based on kinetic analysis has been conducted in order to evaluate thermal hazards of self-polymerization of MDI. The exothermic reactions of MDI are expected to be the polymerization which forms carbodiimide and carbon dioxide, dimerization and trimerization. When MDI is kept in adiabatic condition during 1 week (10080 hours), the simulated result shows runaway reaction can occur in the case that initial temperature was more than $130^{\circ}C$. The relationship between the initial temperature (T, $^{\circ}C$) and TMR is given in a following equation. TMR=$4.493{\times}10^{-7}$ exp ($9.532{\times}10^3$/(T+273.15)) We propose that the relationship gives important criteria of handling temperature of MDl to prevent a runaway reaction.

• 태양에너지
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• 제15권1호
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• pp.73-84
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• 1995

[ $Ca(OH)_2$ ]의 열분해 반응을 이용하는 화학축열법에서는 $Ca(OH)_2$ 입자 충전층의 열전도성이 나쁘기 때문에 축열과정의 소요시간이 길어 실용화에 커다란 장애가 되고 있다. 본 연구에서는 $Ca(OH)_2$ 입자 충전층의 열전달을 촉진시키기 위해 반응기속에 구리판으로 된 전열핀을 설치하고 열분해 탈수반응 실험을 하였다. 그 결과 전열핀이 없는 경우보다 탈수반응에 소요되는 시간을 1/2 이하로 크게 단축시킬 수 있었다.

• 한국안전학회지
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• 제16권2호
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• pp.75-79
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• 2001

For handling and storage of reactive chemicals, the hazard evaluations have been extremely important. In the chemical industry, the most concerns are focused on the thermal harzards such as runaway reactions and thermal decompositions, which are mostly governed by thermodynamics and reaction kinetics or these reactive chemical in the system. This study no investigated the thermal decomposition characteristics of nitrophenylhydrazine isomers by using differential scanning calorimeter(DSC) and accelerating rate calorimeter(ARC). Experimental results showed that exothermic onset-temperatures in nitrophenylhydrazine(NPH) isomers were about 160-$210^{\circ}C$ by DSC and 100-$150^{\circ}C$ by ARC. The decomposition temperature acquired by ARC was about 50-$60^{\circ}C$ lower than that by DSC. Reaction heats were about 40-100cal/g by DSC and 330-750ca1/g by ARC. While ortho isomer of NPH show two distinct exothermic peaks, para isomer shows a single peak in DSC curves. The first exothermic peak for 2-NPH is mainly due to intramolecular dehydration forming 1-hydroxybenzotriazole(HOBT) and the second exothermic peak is mainly due to the decomposition of HOBT formed in the first step of decomposition. The exothermin peak in the DSC curve for 4-NPH is mainly due to dissociation of hydrazino and nitro groups.

• 대한기계학회논문집
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• 제19권2호
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• pp.559-567
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• 1995

The combustion process within a porous inert medium (PIM) burner is numerical studied. A detailed chemical reaction scheme including thermal and prompt NO$_{x}$ reactions is used to predict the formation and destruction of pollutants such as NO$_{x}$ and CO. The reaction paths for NO$_{x}$ formation are divided to quantify the amount of NO$_{x}$ formed through thermal NO$_{x}$ reaction or through prompt NO$_{x}$ reaction. Emission index is calculated to compare the actual mass of NO$_{x}$ or CO produced through the combustion of unit mass of fuel. It is found NO formation in PIM burner is confined in flame zone and formation is suppressed due to heat loss at down-stream of the flame. Higher production of NO through prompt NO reaction path is observed due to the higher concentration of fuel derivative species and its higher diffusion at flame front. For all equivalence ratios, CO emission within PIM burner is lower than that from the one-dimensional freely-propagating flame. PIM burner flame has better NO$_{x}$ emission index from .psi. = 0.75 to .psi. = 1.1. to .psi. = 1.1.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.46-51
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• 2008

In this study, evaluation system of the thermal properties of the exothermic agents was investigated. Exothermic agents property evaluation system was developed by metering variation of power supply. Thermal properties of exothermic agents was affected by material mixture condition of exothermic agents, however, it was not affected by temperature. It is possible to make various exothermic agents by means of regulating thermal properties which is based on property evaluation system of exothermic agents.

• 한국수소및신에너지학회논문집
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• 제16권3호
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• pp.262-268
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• 2005

[ $Zn(BH_4)_2$ ](8.4 wt% theoretical hydrogen storage capacity powders have been successfully synthesized by mechanochemical reaction from mixtures of $ZnCl_2$ and $NaBH_4$ powders in a 1:2 molar ratio in different times. $$ZnCl_2+2NaBH_4{\rightarrow}Zn(BH_4)_2+2NaCl$$ (1) $Zn(BH_4)_2$ powders were characterized by X-ray diffractometry(XRD), and Furier Transform Infrared spectrometry(FT-IR). The thermal stabilities of $Zn(BH_4)_2$ powders were studied by Differential scanning calorimetry(DSC), Thermogravimetry analysis(TGA), and Mass spectrometry(MS). $Zn(BH_4)_2$ can be tested for hydrogen evolution without further purification. The reaction to yield hydrogen is irreversible, the other products being compounds of Zn, and borane. $Zn(BH_4)_2$ thermally decomposes to release borane and hydrogen gas between about 85 and 150$^{\circ}C$.