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Polymerised styrene-butadiene rubber (SBR) 1502 is one of the most common petrochemical products. During the identification of fire evidence, the combustion residues of SBR 1502 highly interfere with the identification of gasoline, a fire accelerant. By conducting thermogravimetric–differential scanning calorimetry (TG-DSC) experiments at various oxygen concentrations (0, 14, and 21 vol.%), the TG-DSC combustion characteristic behaviour of SBR 1502 was investigated. Gas chromatography–mass spectrometry was used to examine the combustion residues at different stages. The results indicated a lack of 2,3-dimethylnaphthalene among the combustion residue of SBR 1502 at the oxygen concentration of 0 and 14 vol.%, thus effectively avoiding the interference of this combustion residue in gasoline identification. The results of the quantitative analysis revealed aromatic hydrocarbon components as the most interfering components for all oxygen concentration and temperature. The combustion residues of SBR 1502 at different oxygen concentrations and combustion stages exhibited different degrees of interference in gasoline identification. Therefore, qualitative and quantitative analyses (hierarchical clustering analysis) were employed to eliminate interference from SBR 1502 in gasoline identification. The results provide theoretical support during the fire identification process. [ABSTRACT FROM AUTHOR]

During fire investigation, gasoline, as a common accelerant, is produced by petroleum cracking. However, the pyrolysis residues of other petrochemicals may interfere with gasoline identification. Polymerised styrene butadiene rubber (SBR) 1502 has combustion characteristics highly consistent with those of gasoline, thus having a great effect on gasoline identification. This study investigated the pyrolysis process of SBR 1502 by using thermogravimetric–differential scanning calorimetry (TG–DSC) and gas chromatography–mass spectrometry (GC–MS) to examine the residues during combustion stages, including pyrolysis and nonpyrolysis stages. The results indicated that 2,3-dimethylnaphthalene in the pyrolysis residues of SBR 1502 in pyrolysis stages 2 and 3 was lacked. However, when SBR 1502 only undergoes the first pyrolysis stage or even earlier (Nonpyrolysis stage), the characteristic components in the residue are similar to gasoline. In addition, mathematical methods were applied to analyse relevance and differences between SBR 1502 and gasoline. The conclusion was that the Pearson product-moment correlation was > 0.990, which may interfere with the identification, and principal component analysis could efficiently distinguish them. The current results can provide an accurate and feasible basis for fire investigation. [ABSTRACT FROM AUTHOR]

Coal spontaneous combustion (CSC) is a global, long-standing thermal hazard in coal mining that causes serious environmental damage, particularly in developing countries. Ionic liquids (ILs) are environmentally friendly, green, economical, and a new type of fire-preventing material that inhibits coal oxidation and alleviates thermal production. In this study, 1-butyl-3-methyl imidazole tetrafluoroborate ([BMIM][BF4]) and 1-butyl-3-methyl imidazole ([BMIM][I]) at various mass ratios (0.0, 0.5, 2.0, 5.0, and 10.0 mass%) were used to treat three types of coal (lignite, 1/3 coking coal, and anthracite) for CSC. The combustion-mass loss and thermal release rate of ILs treated relative to untreated coal samples were investigated using a synchronous thermal analyzer, and the optimal addition mass ratio of ILs was predicted. Not only do ILs have the most efficient inhibiting effect, but they also consider the economic benefit. Per thermogravimetric-differential scanning calorimetry, for the content of 5.0 mass% [BMIM][BF4], the inhibiting effect is favorable for universal applications. In addition, coal samples treated with 5.0 mass% [BMIM][BF4] were subjected to programmed-temperature heating experiment testing. The oxygen consumption rate, inhibiting effect, as well as apparent activation energy, were determined. The inhibiting effect at 120.0–150.0 °C was the most obvious, which provided the basis of the application for CSC prevention. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are a type of environmentally friendly solvents. Several studies have proven that ILs can inhibit the spontaneous combustion of coal (SCC). In this study, a synchronous thermal analyzer was used to analyze the effects of the imidazolium-based IL [BMIM][BF4] on coal of three metamorphic grades. A coal sample exhibiting the optimal inhibiting result was selected to investigate the effect of the oxygen concentration on IL inhibition. The results revealed that the influence of IL on the mass loss process of the three metamorphic grades of coal varied considerably. High inhibition was observed in lignite. However, the IL promoted the mass loss process in 1/3 coking coal and anthracite. The IL delayed the ignition temperature of lignite by 42 °C, whereas those of 1/3 coking coal and anthracite were advanced by 10 and 8 °C, respectively. Furthermore, the initial exothermic temperature of the three treated coal samples was higher than those of the raw coal samples. Compared with the raw coal samples, the heat released per gram of lignite, 1/3 coking coal, and anthracite was reduced by 1142, 353, and 226 J, respectively. The results indicated that the IL had a prominent inhibiting effect on the exothermic properties of the three coal samples, and the inhibiting effect decreased with an increase in the metamorphic grade of coal. Moreover, the oxygen concentration did not alter the inhibition properties of the IL on the SCC. However, the inhibiting effect weakened as the oxygen concentration decreased. [ABSTRACT FROM AUTHOR]

Coal spontaneous combustion (CSC) is an extremely complex physical and chemical reaction between coal and oxygen, and it results in the gradual accumulation of thermal energy that eventually produces conditions that are favorable for combustion. Ionic liquids (ILs) inhibit coal oxidation and reduce the amount of heat that is produced. A synchronous thermal analyzer was used to examine the effects of imidazolium-based ILs on bituminous coal from two sources. The results revealed that with the anion [BF4]−, the inhibiting effect of [BMIM]+ was stronger than that of [EMIM]+. Moreover, with the cation [BMIM]+, the inhibiting effects of [BF4]− were stronger than that of [I]− and [NO3]−. The inhibiting effects of the ILs on CSC were estimated using the Ozawa-Flynn-Wall method, which relates the apparent activation energy to the degree of conversion. The inhibiting effect of [BMIM][BF4] offers a basis for effectively preventing CSC and is favorable for universal application. [ABSTRACT FROM AUTHOR]