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Despite many advantages of the utilization of biomass as a renewable energy source, certain bottlenecks during biomass plant operation can be identified. Transport and collection of biomass as well as non-uniform material characteristics are issues related to decreasing efficiency of logistics and fuel manipulation which can also cause economic problems with biomass collection, transport, and storage. Since biomass is an especially reactive fuel, this has raised concerns over its safe handling and utilization. Fires, and sometimes explosions, are a risk during all stages of fuel production as well as during handling and utilization of the product. This paper presents a novel method for assessing ignition risk and provides a ranking of relative risk of ignition of biomass fuels. Tests within this method include physical and chemical properties of biomass, thermal analysis measurements, and the calculation procedure steps which were made using characteristic temperatures from thermogravimetry recordings. The results of thermogravimetry analysis were used for determination of tangent slope of the mass loss rate curves in devolatilization zone at considered heating rates for all tested samples. Linear interpolation of the data obtained by tangent slope analysis and used heating rates may provide unique straight line for each sample in the ignition testing. Thermogravimetry index of spontaneous ignition (TGspi) is obtained for all samples based on newly established formula. By varying gradient of linear dependence of self-heating coefficient against reference temperatures, mass and heat transfer limitations for various biomasses were discussed. The proposed method is accurate as well as relatively simple and quick, enabling determination of data necessary for design and application of appropriate measures to reduce fire and explosion hazard related to operation of biomass.

Direct Numerical Simulations (DNS) are performed to investigate the process of spontaneous ignition of hydrogen flames at laminar, turbulent, adiabatic and non-adiabatic conditions. Mixtures of hydrogen and vitiated air at temperatures representing gas-turbine reheat combustion are considered. Adiabatic spontaneous ignition processes are investigated first, providing a quantitative characterization of stable and unstable flames. Results indicate that, in hydrogen reheat combustion, compressibility effects play a key role in flame stability and that unstable ignition and combustion are consistently encountered for reactant temperatures close to the mixture’s characteristic crossover temperature. Furthermore, it is also found that the characterization of the adiabatic processes is also valid in the presence of non-adiabaticity due to wall heat-loss. Finally, a quantitative characterization of the instantaneous fuel consumption rate within the reaction front is obtained and of its ability, at auto-ignitive conditions, to advance against the approaching turbulent flow of the reactants, for a range of different turbulence intensities, temperatures and pressure levels.

Despite many advantages of the utilization of biomass as a renewable energy source, certain bottlenecks during biomass plant operation can be identified. Transport and collection of biomass as well as non-uniform material characteristics are issues related to decreasing efficiency of logistics and fuel manipulation which can also cause economic problems with biomass collection, transport, and storage. Since biomass is an especially reactive fuel, this has raised concerns over its safe handling and utilization. Fires, and sometimes explosions, are a risk during all stages of fuel production as well as during handling and utilization of the product. This paper presents a novel method for assessing ignition risk and provides a ranking of relative risk of ignition of biomass fuels. Tests within this method include physical and chemical properties of biomass, thermal analysis measurements, and the calculation procedure steps which were made using characteristic temperatures from thermogravimetry recordings. The results of thermogravimetry analysis were used for determination of tangent slope of the mass loss rate curves in devolatilization zone at considered heating rates for all tested samples. Linear interpolation of the data obtained by tangent slope analysis and used heating rates may provide unique straight line for each sample in the ignition testing. Thermogravimetry index of spontaneous ignition (TGspi) is obtained for all samples based on newly established formula. By varying gradient of linear dependence of self-heating coefficient against reference temperatures, mass and heat transfer limitations for various biomasses were discussed. The proposed method is accurate as well as relatively simple and quick, enabling determination of data necessary for design and application of appropriate measures to reduce fire and explosion hazard related to operation of biomass.

Despite many advantages of the utilization of biomass as a renewable energy source, certain bottlenecks during biomass plant operation can be identified. Transport and collection of biomass as well as non-uniform material characteristics are issues related to decreasing efficiency of logistics and fuel manipulation which can also cause economic problems with biomass collection, transport, and storage. Since biomass is an especially reactive fuel, this has raised concerns over its safe handling and utilization. Fires, and sometimes explosions, are a risk during all stages of fuel production as well as during handling and utilization of the product. This paper presents a novel method for assessing ignition risk and provides a ranking of relative risk of ignition of biomass fuels. Tests within this method include physical and chemical properties of biomass, thermal analysis measurements, and the calculation procedure steps which were made using characteristic temperatures from thermogravimetry recordings. The results of thermogravimetry analysis were used for determination of tangent slope of the mass loss rate curves in devolatilization zone at considered heating rates for all tested samples. Linear interpolation of the data obtained by tangent slope analysis and used heating rates may provide unique straight line for each sample in the ignition testing. Thermogravimetry index of spontaneous ignition (TGspi) is obtained for all samples based on newly established formula. By varying gradient of linear dependence of self-heating coefficient against reference temperatures, mass and heat transfer limitations for various biomasses were discussed. The proposed method is accurate as well as relatively simple and quick, enabling determination of data necessary for design and application of appropriate measures to reduce fire and explosion hazard related to operation of biomass.

Direct Numerical Simulations (DNS) are performed to investigate the process of spontaneous ignition of hydrogen flames at laminar, turbulent, adiabatic and non-adiabatic conditions. Mixtures of hydrogen and vitiated air at temperatures representing gas-turbine reheat combustion are considered. Adiabatic spontaneous ignition processes are investigated first, providing a quantitative characterization of stable and unstable flames. Results indicate that, in hydrogen reheat combustion, compressibility effects play a key role in flame stability and that unstable ignition and combustion are consistently encountered for reactant temperatures close to the mixture’s characteristic crossover temperature. Furthermore, it is also found that the characterization of the adiabatic processes is also valid in the presence of non-adiabaticity due to wall heat-loss. Finally, a quantitative characterization of the instantaneous fuel consumption rate within the reaction front is obtained and of its ability, at auto-ignitive conditions, to advance against the approaching turbulent flow of the reactants, for a range of different turbulence intensities, temperatures and pressure levels.

During the utilization of coal in large power plants, one of the major logistical issues is related to spontaneous ignition of the coal. This characteristic of coal depends on the rank and type of the coal, the content of the moisture and volatile matter as well as particle size distribution. This paper presents the novel approach for determination of spontaneous ignition potential of the coal developed as the internal laboratory experimental method. The experimental tests were performed by thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) of tested samples at five different heating rates: 3, 5, 7, 10 and 20 K min−1 under an air atmosphere. The TGA results were used for determination of tangent slope of the mass loss rate curves in the zone of the release of volatiles at considered heating rates for all coal samples. The linear interpolation of the data obtained by performed tangent slope analysis and heating rates provides the straight line unique for each tested sample. According to the standard method, the slope of the obtained straight line is defined as thermogravimetric index of spontaneous ignition (TGspi). In addition, a new formula for determination of TGspi index was provided. Three different coal samples were analyzed and classified according to the spontaneous ignition potential, based on the obtained values for TGspi by standard procedure and also using a newly proposed method. By varying the gradient of linear dependence of self-heating coefficient against reference temperatures (Tref,i), the mass and heat transfer limitations for different coals were discussed. © 2019 The Combustion Institute

During the utilization of coal in large power plants, one of the major logistical issues is related to spontaneous ignition of the coal. This characteristic of coal depends on the rank and type of the coal, the content of the moisture and volatile matter as well as particle size distribution. This paper presents the novel approach for determination of spontaneous ignition potential of the coal developed as the internal laboratory experimental method. The experimental tests were performed by thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) of tested samples at five different heating rates: 3, 5, 7, 10 and 20 K min(-1) under an air atmosphere. The TGA results were used for determination of tangent slope of the mass loss rate curves in the zone of the release of volatiles at considered heating rates for all coal samples. The linear interpolation of the data obtained by performed tangent slope analysis and heating rates provides the straight line unique for each tested sample. According to the standard method, the slope of the obtained straight line is defined as thermogravimetric index of spontaneous ignition (TG(spi)). In addition, a new formula for determination of TG(spi) index was provided. Three different coal samples were analyzed and classified according to the spontaneous ignition potential, based on the obtained values for TG(spi) by standard procedure and also using a newly proposed method. By varying the gradient of linear dependence of self-heating coefficient against reference temperatures (T-ref,T-i), the mass and heat transfer limitations for different coals were discussed.

During the utilization of coal in large power plants, one of the major logistical issues is related to spontaneous ignition of the coal. This characteristic of coal depends on the rank and type of the coal, the content of the moisture and volatile matter as well as particle size distribution. This paper presents the novel approach for determination of spontaneous ignition potential of the coal developed as the internal laboratory experimental method. The experimental tests were performed by thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) of tested samples at five different heating rates: 3, 5, 7, 10 and 20 K min−1 under an air atmosphere. The TGA results were used for determination of tangent slope of the mass loss rate curves in the zone of the release of volatiles at considered heating rates for all coal samples. The linear interpolation of the data obtained by performed tangent slope analysis and heating rates provides the straight line unique for each tested sample. According to the standard method, the slope of the obtained straight line is defined as thermogravimetric index of spontaneous ignition (TGspi). In addition, a new formula for determination of TGspi index was provided. Three different coal samples were analyzed and classified according to the spontaneous ignition potential, based on the obtained values for TGspi by standard procedure and also using a newly proposed method. By varying the gradient of linear dependence of self-heating coefficient against reference temperatures (Tref,i), the mass and heat transfer limitations for different coals were discussed. © 2019 The Combustion Institute

Metal hydrides are known as a potential efficient, low-risk option for high-density hydrogen storage since the late 1970s. In this paper, the present status and the future perspectives of the use of metal hydrides for hydrogen storage are discussed. Since the early 1990s, interstitial metal hydrides are known as base materials for Ni – metal hydride rechargeable batteries. For hydrogen storage, metal hydride systems have been developed in the 2010s [1] for use in emergency or backup power units, i. e. for stationary applications. With the development and completion of the first submarines of the U212 A series by HDW (now Thyssen Krupp Marine Systems) in 2003 and its export class U214 in 2004, the use of metal hydrides for hydrogen storage in mobile applications has been established, with new application fields coming into focus. In the last decades, a huge number of new intermetallic and partially covalent hydrogen absorbing compounds has been identified and partly more, partly less extensively characterized. In addition, based on the thermodynamic properties of metal hydrides, this class of materials gives the opportunity to develop a new hydrogen compression technology. They allow the direct conversion from thermal energy into the compression of hydrogen gas without the need of any moving parts. Such compressors have been developed and are nowadays commercially available for pressures up to 200 bar. Metal hydride based compressors for higher pressures are under development. Moreover, storage systems consisting of the combination of metal hydrides and high-pressure vessels have been proposed as a realistic solution for on-board hydrogen storage on fuel cell vehicles. In the frame of the “Hydrogen Storage Systems for Mobile and Stationary Applications” Group in the International Energy Agency (IEA) Hydrogen Task 32 “Hydrogen-based energy storage” different compounds have been and will be scaled-up in the near future and tested in the range of 500 g to several hundre

会議情報: 第32回宇宙環境利用シンポジウム (2018年1月15日-16日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, Meeting Information: Space Utilization Research (January 15-16, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan

If a solid material of large surface area is contaminated with a liquid with a propensity to low-temperature thermal oxidation (most often oil high in unsaturated fatty acids), under certain conditions it can self-ignite. To identify the tendency to self-ignition of substances, there have been developed a number of methods, such as differential Mackey test, or recommended the use of other classical methods of thermal analysis, which however are not suited for the analysis of samples of larger volume. DTA and ARC appear to be among the best methods of thermal analysis, for the evaluation of dynamic and kinetic parameters of the process of self-heating of such samples., Pri kombinácii tuhých materiálov s veľkým povrchom a kvapalín so sklonom k nízkoteplotnej termooxidácii (najčastejšie oleje s vysokým obsahom nenasýtených mastných kyselín) môže dochádzať za určitých podmienok k samovznieteniu. Za účelom identifikácie sklonu látok k samovznieteniu boli vyvinuté viaceré metódy ako napríklad diferenčný Mackey test, alebo sú odporúčané sú aj klasické metód termickej analýzy, ktoré však nie sú vhodné pre analýzu vzoriek väčších objemov. Pre skúmanie dynamických a kinetických parametrov procesu samozahrievania takýchto vzoriek sa javia ako najvhodnejšie spomedzi metód termickej analýzy DTA a ARC.

If a solid material of large surface area is contaminated with a liquid with a propensity to low-temperature thermal oxidation (most often oil high in unsaturated fatty acids), under certain conditions it can self-ignite. To identify the tendency to self-ignition of substances, there have been developed a number of methods, such as differential Mackey test, or recommended the use of other classical methods of thermal analysis, which however are not suited for the analysis of samples of larger volume. DTA and ARC appear to be among the best methods of thermal analysis, for the evaluation of dynamic and kinetic parameters of the process of self-heating of such samples., Pri kombinácii tuhých materiálov s veľkým povrchom a kvapalín so sklonom k nízkoteplotnej termooxidácii (najčastejšie oleje s vysokým obsahom nenasýtených mastných kyselín) môže dochádzať za určitých podmienok k samovznieteniu. Za účelom identifikácie sklonu látok k samovznieteniu boli vyvinuté viaceré metódy ako napríklad diferenčný Mackey test, alebo sú odporúčané sú aj klasické metód termickej analýzy, ktoré však nie sú vhodné pre analýzu vzoriek väčších objemov. Pre skúmanie dynamických a kinetických parametrov procesu samozahrievania takýchto vzoriek sa javia ako najvhodnejšie spomedzi metód termickej analýzy DTA a ARC.

If a solid material of large surface area is contaminated with a liquid with a propensity to low-temperature thermal oxidation (most often oil high in unsaturated fatty acids), under certain conditions it can self-ignite. To identify the tendency to self-ignition of substances, there have been developed a number of methods, such as differential Mackey test, or recommended the use of other classical methods of thermal analysis, which however are not suited for the analysis of samples of larger volume. DTA and ARC appear to be among the best methods of thermal analysis, for the evaluation of dynamic and kinetic parameters of the process of self-heating of such samples., Pri kombinácii tuhých materiálov s veľkým povrchom a kvapalín so sklonom k nízkoteplotnej termooxidácii (najčastejšie oleje s vysokým obsahom nenasýtených mastných kyselín) môže dochádzať za určitých podmienok k samovznieteniu. Za účelom identifikácie sklonu látok k samovznieteniu boli vyvinuté viaceré metódy ako napríklad diferenčný Mackey test, alebo sú odporúčané sú aj klasické metód termickej analýzy, ktoré však nie sú vhodné pre analýzu vzoriek väčších objemov. Pre skúmanie dynamických a kinetických parametrov procesu samozahrievania takýchto vzoriek sa javia ako najvhodnejšie spomedzi metód termickej analýzy DTA a ARC.

If a solid material of large surface area is contaminated with a liquid with a propensity to low-temperature thermal oxidation (most often oil high in unsaturated fatty acids), under certain conditions it can self-ignite. To identify the tendency to self-ignition of substances, there have been developed a number of methods, such as differential Mackey test, or recommended the use of other classical methods of thermal analysis, which however are not suited for the analysis of samples of larger volume. DTA and ARC appear to be among the best methods of thermal analysis, for the evaluation of dynamic and kinetic parameters of the process of self-heating of such samples., Pri kombinácii tuhých materiálov s veľkým povrchom a kvapalín so sklonom k nízkoteplotnej termooxidácii (najčastejšie oleje s vysokým obsahom nenasýtených mastných kyselín) môže dochádzať za určitých podmienok k samovznieteniu. Za účelom identifikácie sklonu látok k samovznieteniu boli vyvinuté viaceré metódy ako napríklad diferenčný Mackey test, alebo sú odporúčané sú aj klasické metód termickej analýzy, ktoré však nie sú vhodné pre analýzu vzoriek väčších objemov. Pre skúmanie dynamických a kinetických parametrov procesu samozahrievania takýchto vzoriek sa javia ako najvhodnejšie spomedzi metód termickej analýzy DTA a ARC.

If a solid material of large surface area is contaminated with a liquid with a propensity to low-temperature thermal oxidation (most often oil high in unsaturated fatty acids), under certain conditions it can self-ignite. To identify the tendency to self-ignition of substances, there have been developed a number of methods, such as differential Mackey test, or recommended the use of other classical methods of thermal analysis, which however are not suited for the analysis of samples of larger volume. DTA and ARC appear to be among the best methods of thermal analysis, for the evaluation of dynamic and kinetic parameters of the process of self-heating of such samples., Pri kombinácii tuhých materiálov s veľkým povrchom a kvapalín so sklonom k nízkoteplotnej termooxidácii (najčastejšie oleje s vysokým obsahom nenasýtených mastných kyselín) môže dochádzať za určitých podmienok k samovznieteniu. Za účelom identifikácie sklonu látok k samovznieteniu boli vyvinuté viaceré metódy ako napríklad diferenčný Mackey test, alebo sú odporúčané sú aj klasické metód termickej analýzy, ktoré však nie sú vhodné pre analýzu vzoriek väčších objemov. Pre skúmanie dynamických a kinetických parametrov procesu samozahrievania takýchto vzoriek sa javia ako najvhodnejšie spomedzi metód termickej analýzy DTA a ARC.

If a solid material of large surface area is contaminated with a liquid with a propensity to low-temperature thermal oxidation (most often oil high in unsaturated fatty acids), under certain conditions it can self-ignite. To identify the tendency to self-ignition of substances, there have been developed a number of methods, such as differential Mackey test, or recommended the use of other classical methods of thermal analysis, which however are not suited for the analysis of samples of larger volume. DTA and ARC appear to be among the best methods of thermal analysis, for the evaluation of dynamic and kinetic parameters of the process of self-heating of such samples., Pri kombinácii tuhých materiálov s veľkým povrchom a kvapalín so sklonom k nízkoteplotnej termooxidácii (najčastejšie oleje s vysokým obsahom nenasýtených mastných kyselín) môže dochádzať za určitých podmienok k samovznieteniu. Za účelom identifikácie sklonu látok k samovznieteniu boli vyvinuté viaceré metódy ako napríklad diferenčný Mackey test, alebo sú odporúčané sú aj klasické metód termickej analýzy, ktoré však nie sú vhodné pre analýzu vzoriek väčších objemov. Pre skúmanie dynamických a kinetických parametrov procesu samozahrievania takýchto vzoriek sa javia ako najvhodnejšie spomedzi metód termickej analýzy DTA a ARC.

If a solid material of large surface area is contaminated with a liquid with a propensity to low-temperature thermal oxidation (most often oil high in unsaturated fatty acids), under certain conditions it can self-ignite. To identify the tendency to self-ignition of substances, there have been developed a number of methods, such as differential Mackey test, or recommended the use of other classical methods of thermal analysis, which however are not suited for the analysis of samples of larger volume. DTA and ARC appear to be among the best methods of thermal analysis, for the evaluation of dynamic and kinetic parameters of the process of self-heating of such samples., Pri kombinácii tuhých materiálov s veľkým povrchom a kvapalín so sklonom k nízkoteplotnej termooxidácii (najčastejšie oleje s vysokým obsahom nenasýtených mastných kyselín) môže dochádzať za určitých podmienok k samovznieteniu. Za účelom identifikácie sklonu látok k samovznieteniu boli vyvinuté viaceré metódy ako napríklad diferenčný Mackey test, alebo sú odporúčané sú aj klasické metód termickej analýzy, ktoré však nie sú vhodné pre analýzu vzoriek väčších objemov. Pre skúmanie dynamických a kinetických parametrov procesu samozahrievania takýchto vzoriek sa javia ako najvhodnejšie spomedzi metód termickej analýzy DTA a ARC.

If a solid material of large surface area is contaminated with a liquid with a propensity to low-temperature thermal oxidation (most often oil high in unsaturated fatty acids), under certain conditions it can self-ignite. To identify the tendency to self-ignition of substances, there have been developed a number of methods, such as differential Mackey test, or recommended the use of other classical methods of thermal analysis, which however are not suited for the analysis of samples of larger volume. DTA and ARC appear to be among the best methods of thermal analysis, for the evaluation of dynamic and kinetic parameters of the process of self-heating of such samples., Pri kombinácii tuhých materiálov s veľkým povrchom a kvapalín so sklonom k nízkoteplotnej termooxidácii (najčastejšie oleje s vysokým obsahom nenasýtených mastných kyselín) môže dochádzať za určitých podmienok k samovznieteniu. Za účelom identifikácie sklonu látok k samovznieteniu boli vyvinuté viaceré metódy ako napríklad diferenčný Mackey test, alebo sú odporúčané sú aj klasické metód termickej analýzy, ktoré však nie sú vhodné pre analýzu vzoriek väčších objemov. Pre skúmanie dynamických a kinetických parametrov procesu samozahrievania takýchto vzoriek sa javia ako najvhodnejšie spomedzi metód termickej analýzy DTA a ARC.

Economic and environmental constraints have created increasing demand for (material and energy recovery) and recycling of waste generated from households, commercial and industrial activities. A wide variety of materials waiting for sorting, recovery, recycling and disposal are stored at temporary storage sites (TSS) where physical, biotic and abiotic processes can lead the stored material to spontaneous ignition. Spontaneous fires at TSS are associated with severe social health economic and environmental implications. The objective of the present thesis was to access, quantify and mitigate the risk of spontaneous fires at temporary storage sites. It was found that during the period from 2000 to 2010, spontaneous fires have caused losses of about 49 million SEK (about 5 million Euros) to the Swedish waste and recycling industry. A comparison of two groups of waste operators (non-seasonal storage sites at private companies and seasonal storage sites at municipality owned companies) showed that the number of fire incidents per storage site was higher for the former one. Furthermore, it was found that there is a need to improve the behavior of environmental managers related to safety issues as a group of managers was found to be under the influence of optimism, attribution and availability biases. The managers under the influence of optimism bias preferred to follow low cost risk averting strategies and fire incidents were more frequently reported at their storage sites. The ArcGIS spatial analysis using Boolean and Weighted Linear Combination approach and open burn/open detonation model was used to provide the screening level guidelines for siting new storage sites with a due consideration given to potential off-site consequences of spontaneous fires on downwind population. Furthermore, experiments were conducted to investigate the combustion characteristics of MSW bales. The data suggested that the unwrapped bales might pose higher hazards for adjacently stored mater

Economic and environmental constraints have created increasing demand for (material and energy recovery) and recycling of waste generated from households, commercial and industrial activities. A wide variety of materials waiting for sorting, recovery, recycling and disposal are stored at temporary storage sites (TSS) where physical, biotic and abiotic processes can lead the stored material to spontaneous ignition. Spontaneous fires at TSS are associated with severe social health economic and environmental implications. The objective of the present thesis was to access, quantify and mitigate the risk of spontaneous fires at temporary storage sites. It was found that during the period from 2000 to 2010, spontaneous fires have caused losses of about 49 million SEK (about 5 million Euros) to the Swedish waste and recycling industry. A comparison of two groups of waste operators (non-seasonal storage sites at private companies and seasonal storage sites at municipality owned companies) showed that the number of fire incidents per storage site was higher for the former one. Furthermore, it was found that there is a need to improve the behavior of environmental managers related to safety issues as a group of managers was found to be under the influence of optimism, attribution and availability biases. The managers under the influence of optimism bias preferred to follow low cost risk averting strategies and fire incidents were more frequently reported at their storage sites. The ArcGIS spatial analysis using Boolean and Weighted Linear Combination approach and open burn/open detonation model was used to provide the screening level guidelines for siting new storage sites with a due consideration given to potential off-site consequences of spontaneous fires on downwind population. Furthermore, experiments were conducted to investigate the combustion characteristics of MSW bales. The data suggested that the unwrapped bales might pose higher hazards for adjacently stored mater

Spontaneous ignition of waste stockpiles represents a serious economic and safety problem. The said type of processes are deemed very important for determining a tendency of municipal solid waste (MSW) towards self-ignition, as well as for identifying appropriate technical measures (ventilation, forced cooling) that need to be implemented in order to prevent fires and pollutant emissions from MSW management facilities, especially waste transfer stations, waste storages, etc. The paper describes waste oxidation and spontaneous combustion processes, which are closely related to similar processes occurring in many other organic materials. Regardless of the considered process nature, results indicate that consumption of oxygen and heat transfer rate in the waste stockpile are significant and thus favorable for fire outbreak or explosion incidents. The "constant oxidation rate" values obtained, considered to be the process indicators, were significantly larger than the corresponding values obtained for different coal varieties.

A guide is developed that lays out the process of analyzing spontaneous ignition likelihood. The Frank-Kamenetskii (F-K) theory forms the basis of the approach. The Damkohler number, defined as the dimensionless heat generation parameter for a self-heating body, is described in terms of two key material constants and these materials are related to real incident spontaneous ignition scenarios. The Damkohler number is compared to the critical Damkohler number, value of heat generation at the onset of runaway condition, to determine if spontaneous ignition is likely. Corrections to the critical Damkohler number are described for cases of finite Biot number, low activation energy, and reactant consumption. Heat transfer analysis is needed in terms of a Biot number, and its calculation is described. A specific measurement of the heat transfer in an oven is described. Application of the spontaneous ignition hazard analysis for a real case is presented.

The oven basket method coupled with the Jones version of the crossing point method was used to test the following basket sizes with their respectful concentrations of linseed oil soaked cotton, 5cm (33.3%), 5cm (50%), 5cm (75%), 7.5cm (77%), 10cm (80%) with concentrations measured by weight. Some of the samples reached three different stages; ignition, smoldering or constant smoldering and flaming. The activation energies were 42.37 kJ/mol, 27.40 kJ/mol, 16.97 kJ/mol, 15.76 kJ/mol and 11.73 kJ/mol for the 5cm (33.3%), 5cm (50%), 7.5% (77%) and 10cm (80%) basket sizes. It was concluded that as the concentration and the basket size increased the activation energy decreased. The P and M values along with the reaction rate per unit volume were also calculated. The time to ignition increased as the oven temperature that each sample was tested at decreased and as oven temperatures approached ambient the time to ignition significantly increased topping 5.5 hours for the 5cm (75%) basket size.

The aim of this report is to contribute with information that can be used to improve access to good risk assessments associated with storage of wood pellets. Frank-Kamenetskii theory is described in a manner intended to facilitate for the reader to understand and carry out calculations with the theory. A modeling tool in Microsoft Excel for calculations with Frank-Kamenetskii theory has been developed. A description of constraints that the theory has when it comes to use for storages of wood pellets is given and a summary of alternative modeling techniques have been made. The work has contributed to the development of a methodology for measuring the thermal properties thermal conductivity, diffusivity and specific heat capacity on individual pellets with the Transient Plane Source method (TPS). This has been done through a series of laboratory experiments with TPS measurements in order to examine the significance of possible error sources and to state what you should have in mind when performing this kind of measurements.

Analytical work is presented for the spontaneous ignition of a hydrogen jet emanating from a slot into air. A similarity solution of the flowfield was obtained. This was combined with the species and energy conservation equations, which were solved using activation energy asymptotics. Limits of spontaneous ignition were identified as functions of slot width, flow rate, and temperatures of the hydrogen jet and ambient air. Two scenarios are examined: a cool jet flowing into a hot ambient and a hot jet flowing into a cool ambient. For both scenarios, ignition is favored with an increase of either the ambient temperature or the hydrogen supply temperature. Moreover, for the hot ambient scenario, a decrease in local fuel Lewis number also promotes ignition. The Lewis number of the oxidizer only has a weak effect on ignition. Because spontaneous ignition is very sensitive to temperature, ignition is predicted to occur near the edge of the jet if the hydrogen is cooler than the air and on the centerline if the hydrogen is hotter than the air.

A magazine fire involving 30,715 pounds of Navy propelling charges (hazard class 1.3/mass fire) occurred at Hawthorne AAP. The material was stored in Magazine 116-14-E. The propellant was unserviceable (condition code H), awaiting disposal instructions. At 0930, 9 August 1989, a nearby work crew heard a "bang" followed by smoke and sparks coming from the magazine door vents and smoke from the rear ventilator. The doors were then forced open by the pressure of the burning propellant followed by a large jet of flame. The magazine was allowed to cool overnight. An explosive ordnance disposal (EOD) team entered the magazine the next morning and determined there was no unburned propellant in the magazine. The most probable cause was spontaneous ignition due to low stabilizer of 8-inch, 55-caliber bagged propelling charges (national stock number (NSN) 1320-00-089-4275; Department of Defense identification code (DODIC) D605 located in the left front portion of the magazine. This was based on: the known low stabilizer content (0.04 to .13 percent) of seven 8-inch propelling charges lots located in this area (lot numbers DG-2-CO-68, DGR-1-HAW-55, DGR-11-CO-68, DGR-13-CO-68, DGR-14-CO-68, DGR-5-CO-69, and DGR-8-C-51); heavy fire damage occurring in the left front portion of the magazine; and analysis of observations made by several witnesses., See also ADA235006, Volume 2. Published in Minutes of the Explosives Safety Seminar (24th), held in St. Louis, MO on 28-30 Aug 1990.

The important problem of spontaneous ignition of solids heated by temporarily variant thermal radiant exposure is studied. Available data are examined in the light of a simple heat balance analysis to find that the observed behavior is predictable. An exposition of the elements of this general problem of ignition is made to realize that further research is required to predict the ignition behavior of realistic solids under realistic reradiative and free convective loss conditions. (Author), This article is from the Proceedings of the Asilomar Conference on Fire and Blast Effects of Nuclear Weapons (17th), 30 May-3 Jun 83, Asilomar Conference Center, Pacific Grove, CA., AD-A132 780, p195-198. Prepared in cooperation with Stan Martin and Associates, Redwood City, CA.