Explosion characteristics of combustible wood dust in confined system: Analysis using oxygen consumption energy

Yun Seok Kim,이민철,이동호 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

The explosion characteristics, such as maximum explosion pressure, rate of explosion pressure rise, explosion efficiency, were investigated to determine the roll and significance of oxygen consumption energy in dust explosion. Dust explosion experiments were conducted in a Siwek 20L spherical explosion apparatus for three wood dust samples from a wood-based panel production factory. Unlike gas explosions having maximum explosion pressure at near chemical stoichiometric concentration, both the maximum explosion pressure and the maximum rate of explosion pressure of wood dusts appeared at three times or much higher equivalence ratio. Although there were differences in particle size among tested dusts, in the case of dust of which the mean particle size was not larger than 100 ㎛, P maxappeared at lower equivalent ratios when mean particle sizes were smaller and at higher equivalent ratios when mean particle sizes were relatively larger. Explosion efficiency for all dusts are around 10 %, of which the value is relatively lower than most of other normal combustion, which signifies dust explosion remains 90 % of unburned dust with high fire risks after explosion. In a dust explosion, it is difficult to estimate the weight of suspended dust participating in explosions, especially in fuel rich conditions, so a method for estimating explosion overpressure by applying oxygen consumption energy based on unit volume (1 m 3 , SAPT condition) was newly proposed and verified from the result of explosion efficiency. To practically apply these results to dust treating industry, the assessment procedure for dust explosion influence has been provided by introducing TNT equivalent model and its scaled distance.

입자크기 변화에 따른 마그네슘 분진의 폭발특성

정우진,나가이히로시 한국방재학회 2013 한국방재학회논문집 Vol.13 No.2

We conducted experiments to examine the explosion characteristics of different sizes of micro-sized and nano-sized magnesium dust. These explosion characteristics, such as the maximum explosion pressure and maximum rate of pressure rise, depend on the dust concentration. Changes in the particle sizes do not cause clear differences in the explosion characteristics of nano-sized magnesium dust. However, the explosion characteristic values of micro-sized magnesium dust decrease with increasing particle size. Furthermore, nano-sized magnesium dust showed greater explosion characteristics than micro-sized magnesium dust. The calculated flame propagation velocity showed the same trend as the maximum explosion pressure and maximum rate of the pressure rise. The results of classifying the explosion intensity hazards of a magnesium dust explosion showed that the explosion index increased with the decrease of particle size. 다른 크기를 갖는 나노 사이즈와 마이크로 사이즈의 마그네슘 분진의 폭발특성을 실험적으로 조사하였다. 마그네슘분진의 최대폭발압력과 최대압력상승속도 등 폭발특성은 분진의 농도에 의존하였다. 나노 사이즈 마그네슘분진은 입자크기의 변화에 따른 명백한 폭발특성의 차이는 없었다. 그러나 마이크로 사이즈 마그네슘분진은 입자크기가 증가함에 따라 폭발특성치가 감소하였다. 또한 나노 사이즈 마그네슘분진은 마이크로 사이즈 분진보다 커다란 폭발특성을 보였다. 분진폭발의 화염전파속도를 계산한 결과, 화염전파속도 또한 최대폭발압력, 최대압력상승속도와 동일한 경향을 나타내었다. 그리고 마그네슘 분진폭발의 폭발강도 위험성을 분류한 결과, 입자의 크기가 작을수록 폭발지수가 커졌다.

사료분진의 폭발특성에 관한 연구

이홍주,우인성,홍현경,사민형,김윤선,황명환,황성민,박희철,이주엽 대한안전경영과학회 2011 대한안전경영과학회지 Vol.13 No.4

This study examined into property of flour dust explosion to get the basic data for safety of industry by protecting accident of dust explosion. The experiment was conducted to know the effect of distance between explodes in the experiment device, effect of flour dust concentration, effect of humidity, effect of explosion pressure to the dust concentration and effect of inactive substance additive. The study indicated that explosion was happened effectively at the optimum distance 100mm or less in inter-polar distance, and minimum ignition energy was measured at 6mm. The data of feed concentration to the probability of explosion showed that the smaller the particle diameter was, the larger probability of explosion was, and the higher the dust concentration was, the more increased the pressure of explosion was, but more than upper limit of dust concentration, then the explosion of pressure decreased. For the effect of humidity, the more it contained water, the more decreased the ignition energy of dust was, so increased minimum explosive concentration, and effective water content was minimum 10% or more. Inactive substance additive was effective in adding more than 15% CaCO3 and CaO as substance inhibiting dust explosion, in which CaCO3 was more effective than CaO. the analysis of the flame of dust explosion was performed by high-speed video camera, it showed the size of flame bacame smaller in order that sub feed, main feed, wheat powder. As a result, sub feed was expected to be less dangerous than others.

원료의약품 분진의 폭발 위험성 평가

김원성,이근원,우인성,전상용,Kim, Won Sung,Lee, Keun Won,Woo, In Sung,Jeon, Sang Yong 한국안전학회 2018 한국안전학회지 Vol.33 No.2

Dust explosions are occurring in a variety of industries. A dust explosion caused by a specific energy generates huge amount of energy in the ignition and releases decomposition gas. Damages can be increased since this released decomposition gas can cause second and subsequent explosions. In this study, the goal was to obtain practical information on what could affect the explosion by comparing the characteristics of two kinds of dusts with completely different chemical properties. Three kinds of dusts were measured and evaluated for explosion pressure, dust explosion index, explosion limit and minimum ignition energy. It is possible to grasp the characteristics of each dust and use it as useful accident prevention data in the production of raw material powder.

밀가루분진 및 살리실산분진의 폭발하한농도 및 열적특성 비교에 관한 연구

고재선 한국화재소방학회 2012 한국화재소방학회논문지 Vol.26 No.4

We have examined In order to compare each other from explosion and combustion characteristics about the dusts which collects from manufacturing process of wheat flour and cosmetics manufacturing process of functional Keratin removal soap at the small and medium enterprise style. We measured explosive pressure and explosive lower limit which follows in change of concentration change at the time of talc addition uses Hartman dust explosion apparatus, also measured weight loss and endothermic quantity uses DSC and TGA. The explosion test results show that increased explosive lower limit concentration and explosive pressure decreased by the increased ratio of the talc dust. And the DSC results show that heat flux and temperature decreased by the increased ratio of the talc dust. Also increased in raising temperature causes initial smoldering temperature to move towards low temperature section and the endothermic quantity increased on a large scale. Together the TGA results show that weight loss decreased by the increased ratio of the talc dust. From this research we have assured the successive dust explosion mechanism study will play a key role as a significant safety securing guideline against the dust explosion. 본 연구에서는 중소기업형의 밀가루 제조공정 및 각질제거용 기능성 비누를 생산하는 화장품 제조공정에서의 분진들을 채집하여 폭발 및 열적특성을 비교하기 위해 실험을 수행하였다. 폭발실험은 Hartman식 분진폭발장치를 이용하였고,열적실험은 DSC 및 TGA를 이용하여 활석첨가시 농도의 변화에 따른 폭발압력 및 폭발하한계와 온도에 따른 무게감량과 흡열량을 측정하였다. 폭발실험결과 두 시료 모두 활석분진의 비율이 증가할수록 폭발하한농도가 증가하는 것을 볼수 있었고, 폭발압력은 감소됨을 확인하였다. 그리고 DSC 실험결과 활석의 첨가량이 증가할수록 열유속은 감소하고 온도 또한 약간의 감소상태인 것으로 분석되었다. 또한 두 시료 모두 승온 속도가 증가 할수록 흡열개시온도가 낮은 온도부분으로 이동하고 있으며, 흡열량도 크게 증가하였다. 아울러 TGA 실험결과 활석의 양이 증가할수록 전체 무게감량이줄어드는 것으로 나타났다. 향후 분진폭발메커니즘의 지속적 연구와 보완이 효과적인 분진폭발예방 대책수립에 기여할것으로 기대된다.

분진폭발 억제장치 개발에 관한 연구

이익형,이영자 서울보건대학 1995 서울보건대학 부설 한국보건과학연구소 논문집 Vol.2 No.1

Several methods exist for the prevention of dust explosions and for the mitigation of explosion effects. Explosion supression is a technique by which burning in a confined mixture is detected and arrested during the incipient stages to prevent development of pressure which could result in the damaging effects of an explosion. The main components of this system are high speed explosion detection and activation system to release the suppressant. Explosion tests were conducted in a stainless steel, cylindrical vessel having a volume of 80liter for the development of suppression system in our study. The pressure-time characteristics recorded for each explosion test was used to determine the performance of high speed explosion detection and activation system. Tests with halon suppressant showed a decrease of maximum explosion pressure. An explosion suppression system under our research operated well for high speed explosion detection but not high-rate discharge system. On this study we developed high speed explosion detection and activation technology to discharge the suppressant successifully and anticipated that this technology can be applicable to other explosion protective system.

식료품 분진의 발화 및 폭발 위험성

한우섭,Han, Ou-Sup 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.5

식료품 가공 산업에서 분진폭발사고가 자주 발생하고 있으며 배관이나 장치 내의 화염전파에 의한 폭발피해가 증가하고 있다. 그러나 다양한 분체특성으로 인하여 활용 가능한 화재폭발특성자료가 적다는 문제가 있다. 사고발생 빈도가 높고 사회적 수요가 많은 설탕, 옥수수, 밀가루의 발화 위험성과 폭발특성을 실험적으로 조사하였다. 설탕, 옥수수, 밀가루 분진의 평균입경은 27.56, 14.76, $138.5{\mu}m$로 나타났으며 이러한 분체조건에서 열중량분석(TGA) 및 시차주사열량계(DSC)를 사용하여 발화온도를 조사하였다. 최대폭발압력($P_m$) 및 폭발지수는($K_{st}$) 각각 7.6, 7.6, 6.1 bar 및 153, 133, 61 [$m{\cdot}bar/s$]로서 분진폭발 위험성은 설탕이 가장 높고 밀가루가 가장 작았다. 또한 분진폭발 시의 화염전파로 인한 피해확대 위험성을 평가하기 위하여 분진화염전파의 소요시간을 계산하였으며 화염전파로 인한 폭발피해 위험성은 설탕, 밀가루, 옥수수 분진의 순으로 높았다. Severe dust explosions occurred frequently in food processing industries and explosion damage increase by flame propagation in pipes or plants. However there are few fire explosion data available due to various powder characteristics. We investigated the characteristics of ignition and explosion on sugar, cornstarch and flour dust with high frequency accidents and high social demand. The measurements showed the median diameter of 27.56, 14.76, $138.5{\mu}m$ and ignition temperature has been investigated using by thermo-gravimetric analysis (TGA) and differential scanning calorimeter (DSC). The maximum explosion pressure ($P_m$) and dust explosion index ($K_{st}$) of sugar, cornstarch and flour are 7.6, 7.6, 6.1 bar and 153, 133, 61 [$m{\cdot}bar/s$], respectively. The flame propagation time in duct was calculated in order to evaluate the damage increase due to flame propagation during dust explosion. The explosion hazard increase due to flame propagation was higher in the order of sugar, flour and cornstarch dust.

목재 부유분진의 폭발 위험성 평가

이근원(Keun Won Lee),이수희(Su-Hee Lee),한우섭(Ou-Sup Han) 한국가스학회 2013 한국가스학회지 Vol.17 No.5

분진폭발은 플라스틱류, 제약, 목재, 곡물 저장고, 고체연료 및 화학약품의 제조와 같은 다양한 산업에서 발생되고 있다. 본 연구에서는 폐목재를 재활용하여 Particle board를 생산하는 공정의 사이로 분진, 함머밀 분진 및 뉴송 분진을 선택하여 분진폭발 특성을 평가하였다. 실험은 20 L 구형 폭발용기를 이용하여 목재 부유분진의 최대폭발압력, 분진폭발지수, 폭발한하계, 및 최소 점화에너지를 측정하고, 평가하였다. 이들 연구결과는 Particle board를 생산하는 제조공정의 화재?폭발사고 예방을 위한 공정안전 정보로 활용할 수 있을 것이다. Accidents of dust explosion has been occurred in various industries as a plastics, pharmaceuticals, timber, grain storage, solid fuels and chemicals. In this study, the silo dust, hammer mill dust and Nyusong dust in the manufacturing process of the particle board to utilize west wood, which were selected for this experiment and were evaluated the characteristics of dust explosion. The explosion characteristics such as a maximum explosion pressure, explosion index, lower explosive limit, and minimum ignition energy in suspended dust of the wood by Siwek 20 L apparatus were measured and evaluated for the experiment. The results of this study can be used the process safety measures to prevent accidents of fire and explosion in the suspended dust of wood.

나노 및 마이크로 입자 알루미늄의 폭발 특성

한우섭(Ou-Sup Han),이근원(Keun-Won Lee) 한국가스학회 2014 한국가스학회지 Vol.18 No.5

마이크로 크기의 알루미늄 분진의 폭발 특성에 대한 연구는 많이 조사되어 왔지만 나노 크기의 알루미늄 분진에 대한 연구는 매우 적다. 본 연구에서는 나노 및 마이크로 크기의 알루미늄 분진 (70 nm, 100 nm, 6 μm, 15 μm)이 분진폭발특성에 미치는 영향을 20 L 폭발시험 장치를 사용하여 실험적으로 조사하였다. 부유 상태의 알루미늄 분진의 입자 크기가 감소하면, 나노 크기에서의 알루미늄 분진의 폭발하한농도(LEC)는 마이크로 크기의 알루미늄분진보다 감소하였다. 나노 크기의 알루미늄 분진에서의 폭발특성은 마이크로 크기의 알루미늄 분진과 명확한 폭발성의 차이를 보이지 않았다. 투과 전자 현미경(TEM )에 의해 나노 크기의 알루미늄 입자의 관찰로부터 입자 간의 응집성의 증가가 나노 알루미늄 분진의 폭발성에 영향을 미칠 수 있을 것으로 추정되었다. Explosion characteristics of micro-sized aluminum dusts had been studied by many researchers, but the research of nano-sized aluminum dusts were very insufficient. In this study, an experimental investigation was carried out on the influences of nano and micro-sized aluminum dusts (70 nm, 100 nm, 6 μm, 15 μm) on dust explosion properties of aluminum particles by using 20 L explosion apparatus. With decreasing of particle size in suspended aluminum dusts, the LEC (lower explosion concentration) of nano-sized aluminum is lower than that of micro-sized aluminum. The particle size change of nano-sized aluminum dusts seems no obvious explosion differences than that of micro-sized aluminum dusts. From the observation of nano-sized aluminum particles by TEM (Transmission Electron Microscopy), it is estimated that increase of particles aggregation may have effects on the explosion characteristics of aluminum nanopowders.

발전용 유연탄의 분진폭발 특성 연구

김승환,이주헌,하동명 한국위험물학회 2019 한국위험물학회지 Vol.7 No.2

Recently, the use of various bituminous coal has been increasing in the power generation industry. Disasters may occur with this increase because the combustion characteristics of the carbon dust can not be accurately grasped. Particularly, dust explosion is larger than other explosion risk, so management is needed. Dust refers to solid particles of 0.1㎛ to 100㎛ generated by grinding, handling, abrupt impact, explosion, perforation, heating, crushing, etc., Although studies on spontaneous ignition of bituminous coal are ongoing in Korea, there are few studies of dust explosion. Therefore, this study conducted a dust explosion experiment five times on each mesh by sifting 120-170mesh, 200-230mesh, 230-270mesh, and 270-325mesh using US bituminous coal and domestic bituminous coal. The dust explosion test predicts the lower explosion limit of dust, and the experimental data presented should be used as a reference for securing safety in the process of handling bituminous coal.