Investigations of nitrogen content and thermal decomposition activation energy (Ea) of two different kinds of nitrocellulose (NC) products, NMNC and MNC from the non-fat and original processes of linters,
respectively, were discussed. In this study, differential scanning calorimetry (DSC) and element analyzer (EA) are used, for
the above two chemicals, along with the same nitration condition in use of sulfuric acid (H2SO4) and nitric acid (HNO3) mixing acid. Ea was calculated by our induced model. According to our experimental results, the nitrogen content of NMNC/MNC was 11.71 and
11.55 mass%, in a low nitrogen content condition of mixing acid. The Ea parameters were 319.91 (NMNC) and 347.27 (MNC) kJ mol−1, individually. They indicated that the non-fat process of a linter made a higher degree of stability than the others. This
research also presents an efficient and accurate model of the thermal decomposition property evaluation for non-fat process
of linters. The outcome is believed to be very useful for helping to understand, and be applied as, an inherently safer design
during relevant NC manufacturing processes.
Diphenylcarbonate (DPC) has been regarded as a potential substitute material for highly toxic phosgene, reacting with bisphenol
A (BPA) in a phosgene-free process to produce polycarbonate (PC). For synthesizing DPC, methylphenylcarbonate (MPC) was the
critical intermediate with potential flammability in a transesterification reaction from dimethylcarbonate (DMC) and phenol.
Under the National Fire Protection Association (NFPA) criterion, MPC is viewed as one sort of combustible liquid (Class IIIB).
Once it fires or burns during storage, operation or transportation, it can cause a serious fire and explosion. However, researches
are still scanty in mentioning the basic but crucial fire and explosion features of MPC to date. A sound background of material
safety properties is essential for safe handling; in particular, flammability information is extremely crucial for a specific
chemical during a unit operation to prevent any fire and explosion hazards. In this study, we investigated the explosion limits
(LEL, UEL), maximum explosion pressure (Pmax), maximum rate of explosion pressure rise ((dP/dt)max), and gas or vapor explosion constant (Kg) of MPC, according to its practical operating conditions (1 atm, 250°C, 21 vol.% O2) and by means of a 20 L vessel (20-L-Apparatus).
By surveying and defining the experimental data through flammability tests, these basic but crucial safety-related parameters
on flammability characteristics of MPC were proposed, so as to advance understanding and to avoid fire and explosion accidents
for such relevant processes.
Information about the kinetics and thermal
decomposition of hydrogen peroxide (H2O2)
has been required for safety reasons, due to its broad applications in many
chemical industries. To determine the inherent hazards during H2O2
manufacturing, transportation, disposal, usage, and so on, this study deliberately
selected various H2O2 concentrations
and analyzed them by differential scanning calorimetry (DSC). In addition,
thermokinetic parameters were not only established for each of these reactions,
but also aimed at comprehensive, kinetic models with various tests conducted
at different heating rates.
To build up a comprehensive kinetic
model, various tests were conducted by heating rates of 1, 2, 4, 10C
min–1, respectively. According to dynamic
DSC tests, the experimental curves show that H2O2
decomposition has one exothermic peak and may start to decompose under 47–81C.
The total heat of decomposition is about 192–1079 J g–1.
Not only can these results prevent accidents caused by H2O2
during storage and transportation, but also assess its inherent hazards and
thereby design procedures for emergency response while runaway reactions occurring.
Thermal runaway reactions associated with exothermic behaviors of tert-butyl hydroperoxide (TBHP) solutions and TBHP reacting with alkaline contaminants were studied. A differential scanning calorimetry
(DSC) was used to characterize these inherent behaviors of TBHP solutions with KOH, NaOH, LiOH and NH4OH. The exothermic peak in thermal curves of TBHP solutions with different alkali were detected by DSC thermal analysis. By
thermal analysis, we compared various heats of decomposition of TBHP solutions with alkaline impurities, and determined the
incompatible hazards of various TBHP solutions with alkaline contaminants. Comparing with TBHP in various diluents, the adiabatic
runaway reaction via vent sizing package 2 (VSP2) indicated that aqueous TBHP intrinsically possesses the phenomena of thermal
explosion with dramatic self-reactive rate and pressure rise under adiabatic conditions. Many commercial organic peroxides
may have different hazard behaviors. Therefore, using thermal method to classify the hazards is an important subject.
about the kinetics and thermal decomposition of dicumyl peroxide (DCPO) is
required for safety concerns, due to its wide applications and accident cases.
To understand the inherent hazards during DCPO manufacturing, we selected
various concentrations in different stages and analyzed them by differential
scanning calorimetry (DSC). We evaluated thermokinetic parameters to set up
a simple, but comprehensive kinetic model, with various tests conducted at
heating rates of 2, 4, 6 and 10C min-1
. Subsequently, we established a more efficient, resource-effective, and cost-effective
model of safety evaluation for DCPO with different concentrations, according
to thermokinetic parameters, such as activation energy Ea
is 125.35 kJ mol-1 , frequency factor k0 is 3.12410 12
s-1 , reaction order n is 0.9 and heat of
decomposition ΔH is 750.52 J g-1
for DCPO 99 mass%.
Analytical equations related
adiabatic runaway reactions to programmed scanning thermal curves from differential
scanning calorimetry (DSC) were proposed. Thermal or pressure hazards can
be assessed from the adiabatic trajectories expressed in the analytical equations.
These industrially energetic materials include polymerizable monomers, unstable
organic peroxides and nitro-compounds. Various emergency relief behaviors,
such as tempered vapor, gassy, and hybrid were re-evaluated for calculating
vent sizing or mass flow rates from DSC thermal curves and the related physical
Authors:M. Lin, N. Lin, C. Chen, H. Liaw, and C. Shu
Explosion limits are crucial information for people who handle/operate flammable vapors or gases. It was reported in our previous
studies that there is a theoretical linear relation between the reciprocal of the explosion limits and the reciprocal of the
molar fraction of hydrocarbons diluted with inert carbon dioxide or nitrogen. In this work, oxygenated hydrocarbons were inertized
by inert steam, and the relation of the upper explosion limit and the extent of the inertization was explored. With the assumption
that the adiabatic flame temperatures are the same for all limit mixtures, it was found that the aforementioned linear relation
still holds in case the inert gas is of steam and the flammable material is of oxygenated hydrocarbons. Experimental work
was carried out in a 20-L-Apparatus at 101 kPa and 423 K to measure the upper explosion limit of methyl alcohol, acetone,
and methyl formate diluted with steam, respectively. It was found that experimental results fit the theoretical model very
Authors:Y. Chang, J. Lee, S. Wu, C. Chen, and C. Shu
Flammable chemicals are frequently encountered in industrial processes. Under the safe operation basis and for fire/explosion
danger prevention, it is imperative to recognize the flammability characteristics of these processes, especially under the
working scenarios for elevated pressure and temperature.
This study was conducted to investigate fire and explosion properties, including the explosion limits (LEL and UEL), maximum
explosion overpressure (Pmax), maximum rate of explosion pressure rise (dP/dt)max, gas or vapor deflagration index (Kg) and explosion class (St) of various acetone/water solutions (100, 75, 50 and 25 vol.%) at higher initial pressure/temperature up to 2 atm and 200°C
via a 20-L-Apparatus. We further discussed the safety-related parameters and fire/explosion damage degree variations in the
above aqueous acetone within 1 atm and 150°C. The results offered a successful solution for evaluating the flammability hazard
effect in such a relevant crucial process with elevated pressure and temperature.