• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.101-108
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• 2022

This study analyzed the physicochemical properties and combustion characteristics of dry food waste to evaluate the possibility of using food waste as a solid refuse fuel (SRF). The characteristics of dry food waste as a fuel were analyzed by comparing the difference in properties with SRF, and the combustion characteristics after conversion into fuel were identified. Ultimate analysis, proximate analysis, calorific value analysis, and TGA analysis were conducted using two types of food waste and two types of SRF, and the following results were obtained. The moisture content and ash content of dry food waste were 1.7~10.0 wt.% and 7.8~11.7 wt.%, respectively, which satisfied the quality standards for SRF. The low calorific value of dry food waste was 4,000 ~ 4,720 kcal/kg, which was higher than the quality standard of 3,500 kcal/kg for SRF. As a result of TGA analysis of dry food waste, the combustion reaction started at about 200 ℃ and the highest burning rate was at about 500 ℃. After moisture evaporation between 100 and 200 ℃, initial volatile matter, carbon and residual volatile matter were released and burned between 200 and 500 ℃. Based on the high calorific value and low moisture and ash content of dry food waste, it is considered that it is possible to convert dry food waste into SRF through the application of efficient drying technology and strict quality standard inspection in the future.

• Fire Science and Engineering
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• v.28 no.5
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• pp.71-79
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• 2014

This study was performed to test the combustive properties of Medium Density Fibreboards (MDFs) treated with chemicals of the bis-(dimethylaminomethyl) phosphinic acid (DMDAP), N,N-dimethylethylenediaminomethyl-bis-phosphonic acid (DMDEDAP), piperazinomethyl-bis-phosphonic acid (PIPEABP), and methylpiperazinomethyl-bis-phosphonic acid (MPIPEABP). MDFs were painted in three times with 15 wt% solution of the bis-(dimethylaminomethyl) phosphinic acid and alkylenediaminoalkyl-bis-phosphonic acids at the room temperature, respectively. After drying MDF treated with chemicals, combustive properties and volatile organic compounds (VOCs) contents were examined by the cone calorimeter (ISO 5660-1), test for flame retardant (NEMA Notice No. 2012034), and gas chromatography (KS M ISO 11890-2), respectively. It was indicated that the MDFs treated with chemicals showed the longer time to combustion time (CT) = (442~492) s than that of virgin plate by reducing the burning rate except for CT treated with DMDAP. In adition, the MDFs treated with chemicals showed both of the higher char area (44.33~61.33) kg/kg and char length (10.33~11.67) cm than those of virgin plate. Especially, the MDFs treated with chemicals showed the higher mean volatile organic compounds (VOCs) (0.188~0.333) g/L than that of virgin plate within the prescribed limits. Thus, It is supposed that the combustion- retardation properties were improved by the partial due to the treated chemicals in the virgin MDF.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.309-314
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• 2012

Flame flickering occurs mainly because of the buoyancy force for pool fires under ambient air. The cup-burner flame was used for experimental investigation of the effect of the oxidizer velocity on the gravitational instability. The results showed that the flickering frequency decreased with increasing oxidizer velocity. The frequency-buoyancy relation with nondimensional variables coincided with that of the buoyant flume and pool fires when the characteristic velocity was defined as the difference between the fuel and oxidizer velocities, which implies that the origin of the gravitational instability is the Kelvin-Helmholtz instability in the shear layer. The effect of the oxidizer composition on the instability was also examined through nitrogen dilution in the oxidizer stream. As the concentration of inert gas increased, the length of the blue flame increased and lift-off behavior was observed. The oscillation frequency was independent of the dilution ratio, but was related to the local flame structure.

• Korean Journal of Materials Research
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• v.5 no.7
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• pp.835-841
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• 1995

The deposition properties of Si$_3$N$_4$ deposited by low pressure chemical vapor deposition were studied to evaluate Si$_3$N$_4$as part of multi-layer coatings for anti-oxidation and anti-wear coating of graphite in the propellant-burning environment. Si$_3$N$_4$was deposited on the pack-SiC coated graphite and the tendencies of deposition rate and surface morphology changes with temperatures and reaction gas ratios were investigated. In low deposition temperatures the deposition rate increased tilth increasing temperature but in high temperatures the deposition rate decreased with increasing temperature. The grain size of Si$_3$N$_4$decreased with increasing temperature. In condition that the range of reaction gas ratios is 20$\leq$NH$_3$/SiH$_4$$\leq$40, the deposition rate and surface morphology did not change. The Si$_3$N$_4$deposited at 800~130$0^{\circ}C$ was amorphous, and by post-annealing at 130$0^{\circ}C$ in a $N_2$ambient, the Si$_3$N$_4$crystalized.

• Fire Science and Engineering
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• v.31 no.3
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• pp.1-10
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• 2017

This study examined the risk of accidents when handling hazardous materials in hazardous materials storage facilities without safety facilities. In the case of illegal dangerous cargo containers, the burning rate is very fast in the case of fire, which leads to explosions, that are damaging and difficult to control. In addition, accidents that occur in flammable liquid hazardous materials are caused mostly by accidents that occur in the space due to leakage. Therefore, the variables that affect these accidents were derived and the influence of these variables was investigated. Numerical and computational fluid dynamics programs were used to obtain the following final results. First, when a flammable liquid leaks into a specific space, it is influenced by temperature and relative humidity until a certain concentration (lower limit of combustion) is reached. In the case of temperature, it was found that the reaching time was shorter than the flash point In addition, the effect of variables on pool fire accidents of leakage tanks is somewhat different, but the variables that have the largest influence are the wind speed. Therefore, it is expected that the results of this study will be used as basic data for similar numerical analysis and it will provide useful numerical information about the accidental leakage of hazardous materials under various research conditions.

• Polymer(Korea)
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• v.26 no.2
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• pp.260-269
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• 2002

The fire resistance of particulate polypropylene composite systems were investigated by using various reinforced particles such as zeolite, talc, $CaCO_3$ particles. In this study, The effect of particle size on the thermal properties of composite and the effect of reinforced particles on the fire resistance were studied. The inorganic reinforced particles used in this study were recycled zeolite(average particle diameter=85.34 $mu extrm{m}$), $CaCO_3$ (33.93 $mu extrm{m}$), and talc (18.51 $mu extrm{m}$). The fire resistance of composite systems was thoroughly examined by measuring limited oxygen index (LOI, ASTM D2863) and cone calorimetry (ASTM E1354, ISO 5660). Thermal stability of composite systems was thoroughly examined by measuring TGA. The flame retardants (DBDPO) and reinforced particles reduce the maximum heat release rate (M-HRR) in the order of Talc > $CaCO_3$ > recycled Zeolite. Comparing the cone calorimetry experimental results of the particle reinforced polymer composite system exhibited twice higher efficiency than DBDPO in polypropylene systems, and the LOI also showed similar trends to the cone calorimetry experiments. The optical and scanning electron microscopy techniques were used to investigate the composites ash layer and the core fracture surfaces in the burning process. The reinforcing inorganic particles seemed to accumulate at the surface of ash layer, and subsequently intercept the oxygen transport and heat transfer into the core area.