혼합 액체연료의 화학반응차수 계측에 관한 실험적 연구

최효현(Hyohyun Choi),임준석(Junseok Lim),김철진(Chuljin Kim),손채훈(Chae Hoon Sohn) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.5

본 연구에서는 열분석법을 이용하여 혼합 액체연료의 수치해석에 필요한 여러 가지 인자를 측정하였다. 이러한 열분석법에는 열중량 분석방법(TGA, Thermo-Gravimetric Analyzer)과 시차 주사열량 측정법(DSC, Differential Scanning Calorimetry)이 있다. 열중량 분석방법을 통한 비등온 실험(non-isothermal experimental) 결과를 토대로 Freeman Carroll의 수학적인 후처리 방법을 이용하여 미지의 액체연료의 구성 성분에 대한 동역학적 변수인 활성화 온도와 반응차수로 각각 6128.2 K와 1.4를 얻었다. 그 외 다양한 수학적 처리 방법에 따른 동역학적 변수의 값을 구해보았고, 계산 결과는 처리방법에 따라 약간의 차이를 보였다. Thermal Analyses are conducted to measure various factors of a liquid fuel required for numerical analysis. Thermal Analyses are divided into two different methods of TGA (Thermo Gravimetric Analysis) and DSC (Differential Scanning Calorimetry). Non-isothermal experimental results are analyzed using by TGA. The results are filtered by a Freeman Carroll method. At the same time, chemical parameters of unknown liquid fuel, activation temperature and reaction order are measured to 6128.2 K and 1.4, respectively. Furthermore, the parameters can be obtained by various mathematical methods. It is found that tha parameters depend on the processing method.

반탄화 온도와 승온속도에 의한 바이오매스 열분해 거동

공성호 ( Sung Ho Gong ),안병준 ( Byoung Jun Ahn ),이수민 ( Soo Min Lee ),이재정 ( Jae Jung Lee ),이영규 ( Young Kyu Lee ),이재원 ( Jae Won Lee ) 한국목재공학회 2016 목재공학 Vol.44 No.5

본 연구에서는 반탄화 과정에서 바이오매스 열분해 거동을 열중량 분석과 발생되는 기체분석으로 확인하였다. 반응 온도는 220∼300℃, 승온속도 10∼30℃/min, 반응시간은 110분으로 고정하여 분석하였다. 백합나무 중량감소율은 220℃에서 8.01∼8.81%, 300℃에서 71.86∼77.38%로 나타났으며, 240℃ 이상에서 급격하게 증가하였다. 반면 낙엽송 중량감소율은 300℃에서 49.58∼54.15%로 백합나무와 비교하여 낮았다. 백합나무에 대한 활성화 에너지는 87.32∼91.24 kJ/mol으로 승온속도에 따라 큰 차이를 나타내지 않았으며, 낙엽송에 대한 활성화 에너지는 83.85∼91.60 kJ/mol으로 나타났다. 반탄화 과정에서 발생하는 가스성분은 대부분 헤미셀룰로오스 유래 성분이었으며 반응온도가 증가하면서 성분의 종류 및 농도도 증가하였다. 백합나무에서는 furfural, acetic acid가 고농도로 검출되었다. In this study, the thermal degradation behavior of biomass during torrefaction was studied by thermogravimetric and byproduct gas analysis. Torrefaction temperature, time, and heating rate were 220∼300℃, 110 min, and 10∼30℃ /min, respectively. The degradation rate of yellow poplar was 8.01∼8.81% at 220℃ and 71.86∼77.38% at 300℃ depending on heating rate. The degradation rate significantly increased at temperature over 240℃. On the other hand, degradation rate of larch was relatively low as 49.58∼54.15% at 300℃. The activation energy of yellow poplar was 87.32∼91.24 kJ/mol; these values did not significantly change with heating rate. The activation energy of larch was 83.85∼91.60 kJ/mol. The major components of the gas generated during torrefaction were derived from hemicellulose. The component types and concentrations increased with torrefaction severity. High concentrations of furfural and acetic acid were detected during torrefaction of yellow poplar.

Comparison of Pyrolysis Kinetics Between Rigid and Flexible Polyurethanes

김성현,전병희,Xiang Li,임은정,이경환 한국공업화학회 2007 Journal of Industrial and Engineering Chemistry Vol.13 No.7

The pyrolysis kinetics of rigid and flexible polyurethane were examined using thermogravimetric analysis. During the experiment, some of the main compounds were detected. Rigid polyurethane produced five types of low molecular weight organic products, and flexible polyurethane produced at least eleven types of low molecular weight organic products. The main decomposition range of rigid polyurethane took place between 200 and 410 oC, and flexible polyurethane between 150 and 500 oC. A consecutive kinetic model for the pyrolysis of polyurethanes is proposed. The model was able to simulate the experimental curves with good agreement. Using this kinetic model, the kinetic parameters such as activation energy, frequency factor and reaction order could be determined. The average activation energy of flexible polyurethane was 203.1 KJ/mol, which is almost 1.59 times higher than that of rigid polyurethane, 127.7 KJ/mol.

Studies on the growth, structural, optical, thermal and electrical properties of nonlinear optical cadmium mercury thiocyanate glycol monomethyl ether single crystal

라그하반,A. Bhaskaran,R. Sankar,R. Jayavel 한국물리학회 2010 Current Applied Physics Vol.10 No.2

Single crystals of cadmium mercury thiocyanate glycol monomethyl ether (CMTG) were grown from a mixed solvent of glycol monomethyl ether (GME):water (1:1) by slow evaporation method. The crystal structure and morphology were confirmed by single crystal X-ray diffraction analysis. Presence of functional groups and the coordination of glycol monomethyl ether (GME) and thiocyanate (SCN-) in the CMTG compound were confirmed by FT-IR analysis. Optical transparency of the grown crystal was studied by UV–Vis spectroscopy. Thermal stability and decomposition process were studied by means of TGA and DTA analysis. Dielectric measurement on CMTG single crystal was carried out for various frequency and temperatures. The surface studies by scanning electron microscopy reveals the formation of layer growth pattern indicative of 2D nucleation mechanism. From the second harmonic output power measurement by Kurtz powder method, it is observed that CMTG is a potential material for nonlinear optical applications among the bimetallic thiocyanate adducts series.

Synthesis and characterization of soluble polyimides functionalized with carbazole moieties

Mathews, Anu Stella,Kim, Dongjo,Kim, Youngkyoo,Kim, Il,Ha, Chang-Sik Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of polymer science Part A, Polymer chemist Vol.46 No.24

<P>Here, we report the synthesis and characterization of new soluble polyimides that are functionalized using carbazole moieties in their side chain. As a monomer for synthesizing the polyimides, 4″-carbazole-9-yl-[1,1′;2′,1″] terphenyl-4-4′-diamine and 2-(3-carbazol-9-yl-propyl)-biphenyl-4,4′-diamine were synthesized and then characterized using <SUP>1</SUP>H NMR, <SUP>13</SUP>C NMR, FTIR, UV–visible and photoluminescence spectroscopy, differential scanning calorimetry (DSC), and elemental analysis. The polyimides synthesized via chemical imidization processes were characterized with X-ray photoelectron spectroscopy, gel permeation chromatography, wide angle X-ray diffraction, thermogravimetric analysis, DSC, tensile strength measurement, and dielectric property measurement. Results showed that the synthesized polyimides were soluble in a variety of organic solvents, optically transparent in a visible range, thermally stable, mechanically strong, and considerably low dielectric. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8117–8130, 2008</P> <B>Graphic Abstract</B> <P>We report here new soluble semiconducting polyimides (PIs) containing carbazole moieties in the side chain. For dianydrides were used pyromellitic anhydride (PMDA) or 2, 2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). The carbazole diamine derivatives are 4″-carbazole-9-yl-[1,1′;2′,1″] terphenyl-4-4′-diamine (CzTPDA) and 2-(3-carbazol-9-yl-propyl)-biphenyl-4,4′-diamine (CzHBPDA). All PIs showed high mechanical strength (>1.5 GPa) and extremely high glass transition temperature (>260 °C). Interestingly, most of PIs exhibited low dielectric constant below 3, whilstile the PI films were optically transparent in the visible range (>∼400 nm). Here are structures of CzTPDA and CzHBPDA synthesized in this work. <img src='wiley_img/0887624X-2008-46-24-POLA23109-gra001.gif' alt='wiley_img/0887624X-2008-46-24-POLA23109-gra001'> </P>

The influence of process parameters on the structure and properties of micamechanically activated in an ultra centrifugal mill

Ljubiša Andric 한양대학교 세라믹연구소 2012 Journal of Ceramic Processing Research Vol.13 No.4

This paper presents the results of research on mechanical activation of dry mica in an ultra centrifugal mill with a peripheral comminution path. The variable parameters of the mill operation were: rate of rotor revolution (no = 10.000 and no = 20.000 r.p.m.), circle sieve mesh (80, 120, 200 and 500 µm) and the current intensity. The following technological parameters were studied: mechanical activation time, rotor velocity, mill capacity and specific energy consumption. The mechanically activated powder was examined by application of thermal and thermogravimetric analyses, analysis of the degree of mechanical activation and the specific surface area, as well as X-ray diffraction analysis. The optimal results of the mechanical activation were obtained with a full mill load, using a circle sieve mesh of 80 µm and nominal rate of rotor revolution of 20.000 r.p.m. It was shown that the mechanically activated mica obtained employing these process parameters had passed into the amorphous state.

압축 착화 엔진에서 기존 및 저온 디젤 연소에서 발생하는 배기가스의 입자상 물질에 관한 특성 비교

정용진(Yongjin Jung),신현동(Hyun Dong Shin),배충식(Choongsik Bae) 한국연소학회 2012 KOSCOSYMPOSIUM논문집 Vol.- No.45

The characteristics of particulate matters (PM) from an exhaust gas for conventional and low temperature diesel combustion (LTC) in a compression ignition engine was experimentally investigated by the elemental, thermogravimetric analysis. Morphology of PM was also studied by the transmission electron microscopy. PM for LTC shows that it contains more volatile hydrocarbons, which can be easily evaporated than conventional regime. PM for LTC is comprised of smaller primary particles.

Determination of thermal decomposition kinetics of low grade coal employing thermogravimetric analysis

Prakash Parthasarathy,최항석,황재규,박훈채 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.6

The decomposition kinetics of low grade coals was studied and compared with the kinetics of higher grade coals using thermogravimetric analysis. The effect of atmospheres (air, O2 and N2) on coal decomposition kinetics was also investigated. Experiments were carried out under non-isothermal conditions from room temperature to 950 oC at a heating rate of 10 oC/min. Three kinetic models--multiple linear regression equation, unreacted shrinking core and continuous reaction--were used to determine the kinetic parameters of coal decomposition. From the kinetic parameters determined through the multiple linear regression equation, coal type and the atmosphere had an effect on coal decomposition kinetics. Also, there was some variation in the kinetic parameters of coal decomposition determined by the chosen kinetic models. However, the model employing multiple linear regressions yielded consistent results with respect to theoretical background. Under air, the order of the secondary decomposition of coal samples was found to be 0.88, 1.33, 1.69 and 1.52 for samples A, B, C and D, respectively. The order of the secondary decomposition of coal samples when operated under O2 was 1.09, 1.45, 2.36 and 1.81 for samples A, B, C and D, respectively. Under N2, the order of the secondary decomposition of coal samples was 0.72, 0.79, 1.15 and 1.02 for samples A, B, C and D, respectively.

Copper biosorption by pine cone shell and thermal decomposition study of the exhausted biosorbent

G. Blazquez,M.A. Martın-Lara,E. Dionisio-Ruiz,G. Tenorio,M. Calero 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.5

Pine cone shell (PCS), a vegetable solid waste has been used as effective and efficient biosorbent for the removal of Cu(II) from aqueous solutions. The biosorbent was characterized by elemental analysis,potentiometric titrations, surface area and pore size distribution and FTIR analyses. Batch adsorption experiments were carried out as a function of solution pH, particle size, biosorbent dosage, contact time,and initial metal ion concentration. Then, equilibrium isotherms and kinetic data parameters were evaluated. Equilibrium data agreed well with Langmuir isotherm model. The biosorption capacities of PCS for Cu(II) were determined at 25 8C with the Langmuir model as 6.81 mg/g. The kinetics data fitted well into the pseudo-second-order model with correlation coefficient greater than 0.99. Also, dynamic biosorption studies were carried out using a packed-bed column and the main column parameters were determined. Pine cone shell was shown to be a promising biosorbent for Cu(II) removal from aqueous solutions. Finally, the pyrolysis characteristics of native PCS and Cu-loaded PCS were investigated by thermogravimetric analysis (TGA) in order to study the possible recycling of PCS after its use as biosorbent of copper.

디프로파길 플로렌의 합성과 그 열반응 특성에 관한 연구

諸葛英淳,張相熙 경일대학교 2001 論文集 Vol.17 No.-

Dipropargylfluorene(DPF), a fluorene derivative having reactive acetylenic functionality, was synthesized by the reaction of fluorene and propargyl bromide with the catalyst of NaOH/PhCH2N+Me3Cl- in high yield. The chemical structure of DPF was characterized by NMR (1H- and 13C-), IR, UV-visible spectroscopies, and elemental analysis. The thermal reaction properties of DPF were studied by differential scanning calorimetry and thermogravimetric analysis. The DSC thermogram of DPF exhibited that it start to melt and react at 117℃ and at 247℃, respectively, and it has a broad processing window. However, most of DPF was evaporated from the open sample cell at relatively low temperature in the TGA experiment. The DPF is very volatile in the open chamber, thus it should be cured in the closed chamber.