Vol 62, No 3 (2019)

A mechanism is proposed for the interaction of coal with paramagnetic nitrogen oxides produced in the decomposition of sodium nitrite. The main role in the self-oxidation of coal is played by quinoid structures with high redox potential. Four basic periods are identified in the thermooxidative transformation of coal. These periods differ in the rate of the processes, the quantity of gaseous oxidative products, and their composition. The decomposition products of the coal react most vigorously with the oxidant in the fourth period. That leads rapidly to self-heating of the reaction mixture, culminating in explosive gas liberation.

Industrial needle-coke samples are studied. Their paramagnetic characteristics are determined over a broad range of magnetic fields. For some samples, no pronounced signal from the microwave resonator is observed. This indicates that the conversion of the molecular structure to coke is complete in those samples. For some samples, the ESR spectra contain two sharply resolved signals from centers associated with aliphatic and aromatic fragments. That indicates incomplete structural transformation.

Traditional concepts regarding the influence of the entrainment of coal particles in coking on the quality of coal tar may usefully be expanded. In addition to increase in the ash content, the water content of the tar is increased. To eliminate stabilization of the emulsion forming in the condensation department, a limit of 10–13% has been imposed on the content of coal in the ≤0.2 mm class. Analysis of production data shows that the presence of coal particles smaller than 0.071 mm in the batch increases the density of the coal tar and its content of quinoline-insoluble materials. It is found that the water content of the tar is increased more strongly by the aromatic component of the coal than by the mineral component. The emulsifying properties of dusty coal are greatest for Zh coal and least for G coal.

The criteria of system complexity are physically interpreted for the problem of optimal process organization in chemical engineering. To that end, optimization by means of a thermoeconomic approach using undetermined Lagrange multipliers is considered. The Lagrange multipliers obtained characterize the complexity of the system and represent the unit exergy cost of intermediate streams or product streams, which by definition must be minimized. The Lagrange multipliers obtained by applying the information approach to optimal system organization also characterize its complexity. By analogy, it may be supposed that they reflect the unit information cost of intermediate streams or the product streams similar to thermoeconomic criteria. It was shown that thermoeconomic complexity criteria cannot be used in practice on account of various fundamental limitations. Conversely, information complexity criteria are of practical value since all the characteristics present depend solely on process operating parameters. Decreasing the unit information cost is viewed as a tradeoff between the possibility of additional energy reserves in the system, on the one hand, and the costs of organizing energy production processes, on the other. Accordingly, these criteria may be regarded as hybrid, analogously to thermoeconomic criteria.

The disposal of mobile communication devices, which forms part of their life cycle, is considered in the present work. The valuable components present in various devices (mobile phones, smart phones, tablets, e-books) are noted. On that basis, the yield of basic components is plotted against the type of device. The gaseous emissions associated with the roasting of electronic waste are tabulated. Analysis of existing disposal methods permits the development of a system for the disposal of mobile communication devices based on a combination of mechanical and thermal methods. The reactor employed includes a retort that facilitates the charging of crushed components and their final discharge. The cycle for the continuous operation of two reactors is presented. By combining low-temperature pyrolysis and electrical melting, valuable products may be obtained: gold, silver, copper, and carbon black. The production of granulated fuel from such carbon is discussed. The use of a hydrodynamic scrubber minimizes the environmental impact of the system for disposal of mobile communication devices.