폐타이어 분쇄물의 자연발화현상에 대한 재연실험 및 열분석에 관한 연구

고재선,장만준 한국화재소방학회 2012 한국화재소방학회논문지 Vol.26 No.6

These days, spontaneous ignition phenomena by oxidizing heat frequently occur in the circumstances of processing and storing waste tires. Therefore, to examine the phenomena, in this work, this researcher conducted the tests of fires of fragmented waste tires (shredded tire), closely investigated components of the fire residual materials collected in the processing and storing place, and analyzed the temperature of the starting of the ignition, weight loss, and heat of reaction. For the study, this researcher conducted fire tests with fragmented waste tires in the range of 2.5 mm to 15 mm, whose heat could be easily accumulated, and performed heat analysis through DSC and TGA, DTA, DTG, and GC/MS to give scientific probability to the possibility of spontaneous ignition. According to the tests, at the 48-hour storage, rapid increase in temperature (178℃), Graphite phenomenon, smoking were observed. And the result from the DTA and DTG analysis showed that at 166.15℃, the minimum weight loss occurred. And, the result from the test on the waste tire analysis material 1 (Unburnt) through DSC and TGA analysis revealed that at 180℃ or so, thermal decomposition started. As a result,the starting temperature of ignition was considered to be 160℃ to 180℃. And, at 305℃, 10 % of the initial weight of the material reduced, and at 416.12℃, 50 % of the intial weight of the material decreased. The result from the test on oxidation and self-reaction through GC/MS and DSC analysis presented that oxidized components like 1,3 cyclopentnadiene were detected a lot. But according to the result from the heat analysis test on standard materials and fragmented waste tires, their heat value was lower than the basis value so that self-reaction was not found. Therefore, to prevent spontaneous ignition by oxidizing heat of waste tires, it is necessary to convert the conventional process into Cryogenic Process that has no or few heat accumulation at the time of fragmentation. And the current storing method in which broken and fragmented materials are stored into large burlap bags (500 kg) should be changed to the method in which they are stored into small burlap bags in order to prevent heat accumulation. 본 연구에서는 최근 빈번히 발생하고 있는 폐타이어의 가공 및 저장상황에서의 산화열에 의한 자연발화현상을 규명하기 위해 폐타이어 분쇄물에 대한 화재 재연실험과 가공 및 저장장소에서 수거한 화재 잔존물에 대한 면밀한 성분 분석및 발화개시온도, 무게감량, 반응열 등을 분석하였다. 이를 위해 열축적이 용이한 폐타이어 분쇄물 2.5~15 mm 범위의파쇄된 분쇄물을 대상으로 재연실험 및 DSC 및 TGA, DTA, DTG, GC/MS를 통한 열분석을 시행하여 자연발화의 가능성에 대한 과학적인 개연성을 부여하고자 하였다. 연구결과를 살펴보면 재연실험을 통하여 관찰한 결과 48시간 저장시에 온도의 급상승(178℃) 및 탄화현상, 연기발생이 관찰되었다. 또한 DTA, DTG 분석한 결과 166.15℃에서 최초중량감소가 일어나는 것으로 분석되었다. 아울러 DSC 및 TGA를 이용한 폐타이어 분쇄물 1(Unburnt)의 실험결과180℃ 부근에서 열분해를 시작하는 것으로 나타나 폐타이어의 발화 개시온도는 160~180℃라고 말할 수 있다. 그리고305℃에서 최초 원료 무게의 10 % 중량감소가 있었고, 원료 무게의 50 % 중량감소는 416℃로 분석되었다. 또한 GC/MS와 DSC를 이용한 산화성 및 자기반응성시험에 있어서는 1,3 cyclopentnadiene 등 산화성성분이 다량 검출되었지만표준물질과 폐타이어 분쇄물과의 열분석실험결과 기준치 이하로 분석되어 자기반응성은 없는 것으로 분석되었다. 따라서 폐타이어의 산화열에 의한 자연발화현상을 방지하기 위해서는 분쇄시 열축적이 적거나 없는 냉동파쇄방식 등의 가공공정으로 전환유도를 고려해야하며 현재 파쇄·분쇄물을 대형 마대(500 kg)로 저장하는 방식에서, 마대를 소형화하여 분쇄물을 분산 저장하는 등의 방법으로 열축적을 방지해야한다.

제조공정상 발생하는 비산분진의 화재ㆍ폭발 위험성에 대한 열적특성 비교에 관한 연구

Ko Jae Sun 한국재난정보학회 2014 한국재난정보학회 논문집 Vol.10 No.1

본 연구에서는 잠재적인 화재 및 폭발 위험성이 있는 밀가루 제조공정에서의 분진 및기능성비누제조공정에서의살리실산분진, 합판제조공정에서목분, 폐타이어처리 공정에서 발생하는 분진들을채집하여 열적특성을 비교하기 위해 실험을수행하였다. DSC 실험결과 대상시료 모두 활석의 첨가량이 증가할수록 열 유속은 감소하고 온도 는 감소상태인 것으로 분석되었다. 이는 분해속도가 줄어드는 것이고, 위험성이 감소 하고있는것을나타내는것이다. 그러나대상시료 모두 승온속도가증가할수록흡열 개시온도가 낮은온도 부분으로이동하고있으며, 흡열량도 크게증가하였다. 이는 승 온속도가증가할수록시료의 분해위험성이증가하는것으로분석되었다. 아울러TGA 실험결과대상시료모두 무게감량의비율은활석의양이증가할수록전체 무게감량이 줄어들어열적안정성을확보하는것으로나타났다. 향후 분진폭발메커니즘의지속적 연구와 보완이 효과적인 분진폭발예방 대책수립에 기여할 것으로 기대된다. This study carried out an experiment in order to compare thermal characteristics after collecting dust generated in the process of disposing of waste tire, plywood flour in the process of manufacturing plywood, salicylic acid dust in the process of manufacturing functional soap, and dust in the process of manufacturing wheat powder, which has potential fire and explosion hazard. According to the results of experiment, the analysis showed that all samples subject to the experiment were in the condition where heat flux decreased and temperature decreased as the quantity of added talc was increased. This shows that decomposition rate decreased, and hazard decreased. However, in all of samples subject to the experiment, as heating rate increased, endothermic onset temperature moved to the low-temperature part, and the amount of absorbed heat was largely increased. This showed that the decomposition hazard of sample increased as heating rate increased, according to the analysis. Besides, TGA experiment results showed that thermal stability was secured because total weight loss decreased as the amount of talc was increased for all samples subject to the experiment regarding the ratio of weight loss. It is expected that the continuous research and supplementation of dust explosion mechanism in the future will contribute to the establishment of measures for the effective dust explosion prevention.

TGA를 이용한 고온 조건에 노출된 시멘트 페이스트 경화체의 질량감소율 특성

지우람 ( Ji Woo-ram ),신기돈 ( Shin Ki-don ),조현서 ( Cho Hyeon-seo ),이건철 ( Lee Gun-cheol ) 한국건축시공학회 2018 한국건축시공학회 학술발표대회 논문집 Vol.18 No.2

In this study, TGA analysis of hardened cement paste with fire damage was performed. The mass reduction rate of 600 ℃ specimens was about 22 ~ 25%, and the sample of 800 ℃ showed the mass loss rate of 9 ~ 13%. As the target temperature and hold time increased, the mass reduction rate decreased. As the depth increased, the mass reduction rate decreased.

Finite Element Analysis and Performance Comparison of Leaf Spring Based on Unidirectional Sisal Fiber-Reinforced Epoxy Composite Against Woven Fiber-Reinforced Composite

Mohammed Irfan Khan,Chitresh Nayak 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9

The objective of this work is to examine sisal fiber-reinforced epoxy composite to replace metallic leaf spring in electric vehicles. The fiber is heat treated for the improvement of interfacial strength of the composite, before reinforcing them in epoxy matrix in unidirectional orientation, and woven geometry. Composite prepared from hand-layup method is further investigated to explore the mechanical properties required for the efficient performance of leaf spring. Experimentation reveals the magnitude of tensile, flexural, and impact strengths of the composite to be 65 MPa, 170 MPa, 13 MPa and 53 MPa, 148 MPa, 14 MPa, respectively, for both unidirectional and woven geometry. The thermal response of the fabricated composites is estimated by thermogravimetric analysis (TGA), and the fractured specimens are examined under electron microscope. Experimental results of composites are imported in simulation software for finite element analysis. The result of this investigation shows that maximum deformation and von Mises stress obtained are 59.77 mm, 224.87 MPa and 45.339 mm, 219.23 MPa for unidirectional and woven composite leaf spring, respectively. In addition, scanning electron microscopy (SEM) is used to analyse the strained surfaces to get a better understanding of the microstructure and the process of failure.

Synthesis and growth of sodium bitartrate monohydrate a new organometallic nonlinear optical single crystal

V. Siva Shankar,R. Siddheswaran,R. Sankar,R. Jayavel,P. Murugakoothan 한국물리학회 2009 Current Applied Physics Vol.9 No.5

Sodium bitartrate monohydrate (SBTMH) a new organometallic nonlinear optical material, with molecular formula, [C4H5NaO6 . H2O] has been synthesized at ambient temperature. Spectral, thermal and optical techniques have been employed to characterize the new material. Bulk single crystals of size 13 × 4 ×4㎣ of SBTMH have been grown by slow cooling method. The unit cell parameters of the grown crystal were determined by single crystal XRD. Functional groups present in the sample were identified by FTIR spectral analysis. Thermal stability of SBTMH was determined using TGA/DTA. The grown crystals exhibit nonlinear properties. The dielectric response of the crystal with varying frequencies was studied. The optical transparency range and the lower cut-off wavelength of the material were identified from the UV–vis–NIR absorption spectrum. Sodium bitartrate monohydrate (SBTMH) a new organometallic nonlinear optical material, with molecular formula, [C4H5NaO6 . H2O] has been synthesized at ambient temperature. Spectral, thermal and optical techniques have been employed to characterize the new material. Bulk single crystals of size 13 × 4 ×4㎣ of SBTMH have been grown by slow cooling method. The unit cell parameters of the grown crystal were determined by single crystal XRD. Functional groups present in the sample were identified by FTIR spectral analysis. Thermal stability of SBTMH was determined using TGA/DTA. The grown crystals exhibit nonlinear properties. The dielectric response of the crystal with varying frequencies was studied. The optical transparency range and the lower cut-off wavelength of the material were identified from the UV–vis–NIR absorption spectrum.

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.

Acid Sludge로 오염된 토양의 열탈착 공법 적용

박상민 ( Sang-min Park ),전필용 ( Pil-yong Jeon ),신수연 ( Su-yeon Shin ),박응렬 ( Eung-ryeol Park ),고성환 ( Sung-hwan Go ),정홍배 ( Hong-bae Jung ),백기태 ( Ki-tae Baek ) 한국환경기술학회 2016 한국환경기술학회지 Vol.17 No.1

본 연구는 Acid sludge 폐기물 매립에 의한 탄화수소로 오염된 인도네시아 정유플랜트 부지 토양을 대상으로 초기특성분석 및 열중량 분석(TGA-DSC)을 통해 열탈착 공법의 적용가능성을 확인하였다. 해당부지의 오염물질 성분은 GC/FID 분석을 통해 고체성분의 paraffin (C₁₈H₃₈~C₃₇H₇₆) wax계열로 확인되었다. 열중량 분석을 통해 질량변화가 가장 많은 구간은 364~461℃사이로 확인되었으며 이것은 이 온도 구간에서 대부분의 유기물이 제거되는 것을 나타낸다. 또한 약 400℃에서 가장 높은 DSC그래프가 나타났기 때문에 대부분의 유류오염물질들은 400℃에서 제거될 것으로 예상되었다. 이 결과를 기초로 열탈착 실험을 한 결과, 오염토양의 최적 열탈착 온도 조건은 약 350℃로 나타났으며 이 온도에서 TPH 농도는 인도네시아 환경기준 이하로 제거되었다. This study investigated the potential of thermal desorption of the soil contaminated with hydrocarbon in refinery site, Indonesia, which was contaminated by landfilling acid sludge. In this study, the characteristics of contaminated soil was confirmed and thermal gravimetric analysis (TGA) and differential scanning calorimeter (DSC) analysis were carried out. Contaminant was confirmed as paraffin (C₁₈H₃₈~C₃₇H₇₆) wax. In the results of TGA-DSC, the most of the organic matter was removed at 364~461℃ and the most contaminants was desorbed at 400℃. Based on these results, the optimum condition of thermal desorption was expected to 350℃ and hydrocarbons in the soil was removed under Indonesia standard in the temperature range

TGA-DSC 장비를 이용한 엔진오일내 연료희석량 분석방법 연구

전경주(Kyoungju Jeon),용승열(Seungryoul Yong) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Kinetic study of the thermal decomposition of uranium metaphosphate, U(PO₃)₄, into uranium pyrophosphate, UP₂O₇

Yang, Hee-Chul,Kim, Hyung-Ju,Lee, Si-Young,Yang, In-Hwan,Chung, Dong-Yong ELSEVIER 2017 JOURNAL OF NUCLEAR MATERIALS Vol.489 No.-

<P><B>Abstract</B></P> <P>The thermochemical properties of uranium compounds have attracted much interest in relation to thermochemical treatments and the safe disposal of radioactive waste bearing uranium compounds. The characteristics of the thermal decomposition of uranium metaphosphate, U(PO<SUB>3</SUB>)<SUB>4</SUB>, into uranium pyrophosphate, UP<SUB>2</SUB>O<SUB>7</SUB>, have been studied from the view point of reaction kinetics and acting mechanisms. A mixture of U(PO<SUB>3</SUB>)<SUB>4</SUB> and UP<SUB>2</SUB>O<SUB>7</SUB> was prepared from the pyrolysis residue of uranium-bearing spent TBP. A kinetic analysis of the reaction of U(PO<SUB>3</SUB>)<SUB>4</SUB> into UP<SUB>2</SUB>O<SUB>7</SUB> was conducted using an isoconversional method and a master plot method on the basis of data from a non-isothermal thermogravimetric analysis. The thermal decomposition of U(PO<SUB>3</SUB>)<SUB>4</SUB> into UP<SUB>2</SUB>O<SUB>7</SUB> followed a single-step reaction with an activation energy of 175.29 ± 1.58 kJ mol<SUP>−1</SUP>. The most probable kinetic model was determined as a type of nucleation and nuclei-growth models, the Avrami-Erofeev model (A3), which describes that there are certain restrictions on nuclei growth of UP<SUB>2</SUB>O<SUB>7</SUB> during the solid-state decomposition of U(PO<SUB>3</SUB>)<SUB>4</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermal decomposition kinetics of U(PO<SUB>3</SUB>)<SUB>4</SUB> into UP<SUB>2</SUB>O<SUB>7</SUB> was investigated. </LI> <LI> The thermal decomposition followed a single-step reaction with an activation energy of 175.3 ± 1.6 kJ mol<SUP>−1</SUP>. </LI> <LI> The most probable kinetic model was determined as a type of nucleation and nuclei-growth models, the Avrami-Erofeev (A3). </LI> </UL> </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.