Abstraсt: This article describes the world experience of using hydrogen fuel cells in road transport. Examples of the use of hydrogen fuel cells as power plants, both for passenger cars, and for trucks and buses are given. It is shown that this industry is rapidly developing due to the extremely high prospects of the approach in the field of ecology and in conditions of decreasing oil reserves.
Keywords: fuel cells, hydrogen energy, automobile transport.
Abstraсt: The physical and mechanical properties of the secondary copolymer of propylene with ethylene, filled with rice husk, were studied, depending on the method of processing the polymer composite. The processing of a polymer composite by injection molding, as compared to pressing, makes it possible to reduce the degree of crystallinity of the polymer matrix and, as a consequence, to reduce the elastic modulus of the material. This increases the resistance of the plastic product to deformation both in the process of static rupture and bending, and in the process of dynamic impact.
Keywords: copolymer of propylene with ethylene, physical and mechanical properties, injection molding, pressing.
Abstraсt: Three new drugs, such as (2R) -2-amino-3-hy-droxypropanoic acid (D-serine), ® -4-amino-3-isoxaz-olidinone (D-cycloserine) and 4 – [[ 4 – [(3-Oxo-1,2-ox-azolidin-4-yl) iminomethyl] phenyl] methylidenemino] -1,2-oxazolidin-3-one (terizidone) were investigated in this work. There were determined the main fire and explosion hazard indicators for all substances by calculation and experimental methods. Thermal analysis with determination of kinetic parameters of thermal decay by Kissinger method was also carried out. The results are included in safety certificates for substances to ensure safety at work.
Keywords: d-serine, d-cycloserine, terizidone, fire and explosion hazard of substances, ignition temperature, thermal analysis, enthalpy of formation, enthalpy of combustion, temperature of the beginning of intense exothermic decomposition.
Abstraсt: The comparative consumption of sulphuric acid for the decomposition of phosphate raw materials from various deposits is presented. Various methods of processing phosphogypsum into target products are analyzed. It has been shown that phosphogypsum from JSC «Ammofos-Maxam» consists of dihydrate calcium sulfate and about 7-8% quartz, phosphorite and phosphoric acid. The process of gypsum conversion using diammophos pulp (pH = 7.5) has been studied depending on the WPA: Gypsum ratio (2: 1; 2.5: 1; 3: 1), process temperature (30; 50°C) and stirring duration (30; 60; 120; 180 min.). After the reaction, the pulp is separated into liquid and solid phases. The washed and dried solid phase is a precipitate, and its liquid part is a solution of ammonium sulfate with a mixture of ammonium phosphate. The material balance has been calculated and a technological scheme for processing phosphogypsum has been proposed, which makes it possible to obtain ammonium sulfate phosphate with precipitate by adding an ammophos suspension to the liquid phase, drying and granulating sulfoammophos pulp.
Keywords: phosphogypsum, ammonized phosphoric acid, conversion, precipitate, ammonium sulfate solution, sulfoammo-phos, composition, material balance, technological scheme.
Abstraсt: The article presents a model of an absorption column for the separation of ethanepropane fraction of a gas fractionation unit, used to optimize technological modes and assess the design parameters of the apparatus. The column model was developed in the UniSim Design modeling software environment.
Keywords: modeling, absorption tower of gas fractionation plant, unisim design.
Abstraсt: The number of studies devoted to the development of energy storage devices is increasing due to the growing share of alternative energy sources in the structure of global electricity production. Among large-scale energy storage facilities, redox flow batteries are the most promising for a number of reasons. However, even for the most studied type of such energy storage devices – all-vanadium redox flow battery – there is a significant gap between the key specific characteristics of laboratory prototypes and commercially realized power plants. This work presents a battery prototype of 10 membrane-electrode assemblies where all the main problems arising during the transition from a single cell to a battery are minimized due to a number of original design solutions. The manufactured battery functions stably with an energy efficiency of more than 70% on a scale of 100 charge-discharge test cycles.
Keywords: batteries, electrochemical current sources, redox flow battery, membrane-electrode assembly, vanadium redox flow battery.
Abstraсt: The paper examines the influence of ultrasonic welding on metallized carbon strips. The results of evaluating the strength characteristics of carbon strips depending on the modes of ultrasonic welding are presented. The results of the structural assessment and qualitative assessment of the obtained samples after experiments on bonding the layers of a carbon metallized tape by ultrasonic welding to increase the strength of the final samples are presented. An evaluation model, algorithms for deriving boundary conditions and determining the category of the obtained samples have been developed.
Keywords: carbon fabrics, structural analysis, ultrasonic welding.
Abstraсt: To separate the light group of rare earth elements (REE) La, Ce (III), Pr, and Nd along the Ce(III)/Pr line from nitrate solutions with a low concentration of nitric acid with a salting-out agent ammonium nitrate and without a salting-out agent, it was proposed to use solutions of synergistic mixtures of methyltri-nitrate n-octylammonium and tri-n-butyl phosphate in a hydrocarbon solvent. Compositions of extraction mixtures with separation coefficients along the Ce(III)/Pr line of more than 1.65 were determined. The main parameters are calculated – the number of stages, the ratio of the volumes of the aqueous and organic phases for the extraction and washing parts of counter-current extraction cascades with the supply of the initial solution of the mixture to be separated into the central part of the cascade for the variants of separation from low-acid nitrate solutions with and without a salting-out agent. It has been shown that the effective separation of a four-component mixed solution containing light REEs can be carried out in cascades containing from 25 to 56 stages at ratios of volumes of organic and aqueous phases from 1: 1 to 3: 1 in different parts of the cascade.
Keywords: lanthanum, cerium (III), praseodymium, neodymium, extraction, separation, nitrate solutions, synergistic mixtures, methyl-tri-n-octylammonium nitrate, tri-n-butyl phosphate.
