To expand the database of kinetic parameters used for modeling the ignition of coals and their processing waste, promising coal-water slurry and coal-water slurry containing petrochemicals, studies have been performed on an experimental setup using thermal gravimetric analysis. The research into coals of various ranks (flame, gas, coking, low-caking, and non-baking) and their processing waste (filter cakes) has yielded the decomposition parameters of the organic matter of coal and the formation of volatile substances as well as the oxidation parameters of the coke residue of all the coals and filter cakes under study. The studies cover the temperature range of the burning processes: 450-1300 K (for low-, medium-, and high-temperature burning modes). We have ascertained the dependence of kinetic parameters (pre-exponential factor and activation energy) describing the thermal decomposition of the organic matter of coal on the rank of coals and filter cakes. The findings show that the kinetic parameters describing the thermal decomposition of the organic matter of coal and its processing waste are practically the same. The thermokinetic parameters of coke residue oxidation are close for all the coals under study but they differ significantly for coke residue of filter cakes. The values of thermokinetic parameters obtained in the research are necessary to devise adequate physical and mathematical models and perform numerical studies (for mathematical modeling) of fuel slurry combustion processes in the combustion chambers of power plants.
The
lack of effective technologies to use coal processing waste
and waste flammable liquids is a major research and development problem.
To address this problem, we study the ignition characteristics and
conditions for coal–water slurries (CWS) based on these wastes.
The key challenge posed by the wastes under study is their poor reactivity
(they require more power resources for sustainable ignition). Therefore,
this paper suggests adding a highly reactive material (charcoal) in
a low concentration to coal–water-slurry containing petrochemicals
(CWSP) based on wastes. Individual CWSP droplets are studied in a
model combustion chamber. The integral characteristics of the processes
under study (ignition delay time and minimum oxidizer temperatures
sufficient for ignition) are determined for a CWSP droplet of 0.5–2
mm in radius fixed at the junction of a low-inertia thermocouple using
a high-speed (up to 105 fps) video camera and Tema Automotive
software. We compare the ignition characteristics of CWSP compositions
based on charcoal and brown coal as well as filter cakes (processing
waste) of coking, low-caking, and non-baking coals in an oxidizer
flow (temperature of 600–1000 K and velocity of 0.5–5
m/s). Charcoal is a promising additional component for the CWS and
CWSP. In view of ecological, economic, and energy-related aspects,
it is advisible to use charcoal as an additive to intensify the CWS
and CWSP ignition. Even a small addition (within 10–15% in
relative mass concentration) of this component may significantly reduce
the limit (minimum) temperature of sustainable ignition and ignition
delay time (inertia).
<p class="ADMETabstracttext">The paper is devoted to the study of the ion exchange encapsulation of nicotinic acid in nanocontainers on polymer matrices. Dowex-50 cation exchanger, sulphonated polymer based on metacyclophanoctol, polymer zirconium phosphate, and strongly basic Dowex-1 anion exchanger are used as polymer matrices. It was confirmed that commercial ion exchangers can encapsulate up to 0.64 g of nicotinic acid per gram of polymer. The high elution rate of nicotinic acid from nanocontainers via the ion exchange mechanism makes it possible to achieve the desired pharmacokinetics of drug release in vivo.</p>
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