Vol 62, No 10 (2019)

The properties of bituminous Zh coal are studied. The change in gas content over time in sealed bed samples is determined. It is found that, for all size classes of coal, the pressure of the gas released from the coal stabilizes over 24 h; about half of the pressure increase occurs in the first 3 h. The gas content is greater in coal of the 5–10 mm class than in coal of the ≤3 mm class.

Experimental briquetting of substandard coke breeze at PAO Koks is considered. The briquets are characterized by drop strength of 99.9%. Their ash content is close to that of the coke breeze, thanks to the low ash content of the binder. The briquettes’ elevated yield of volatiles is associated with the binder’s high yield of volatiles. In industrial experiments, the briquets are used to produce hot metal in a cupola furnace. Replacement of 20% and 40% of the coke in the batch by the briquets does not impair the smelting process.

In the present study, the kinetics of isothermal gasification of metallurgical coke by carbon dioxide was investigated through the use of thermogravimetry. For gasification of carbonaceous materials, two typical conversion models, i.e. the John-Mehl-Avrami model (JMA) and the random pore model (RPM), were employed to portray the reaction process. Compared with the RPM model, the JMA model was found to be the suitable conversion model after the further comparison of the Arrhenius parameters calculated from these two conversion models.

Research on decreasing the consumption of coal tar and expanding the range of materials used in binder-pitch production by adding coal extracts and chemical byproducts is reviewed. The liquid byproducts employed are tall oil, semicoking tar, and residues of styrene distillation; the solid byproducts are rubber granules and polycarbonate wastes.

Means of improving the operational efficiency of circulatory water systems at coke plants are considered. Attention focuses on systems in which the industrial-grade water is prepared by means of an activated solution of coagulant (aluminum sulfate). The activation of coagulant solutions and their use to treat industrial-grade water is studied. The influence of the settling velocity and content of suspended particulates on the effectiveness of water clarification is investigated. Effective means of activating the coagulant solutions are identified. Formulas are proposed for use in improving the water processing in circulatory water systems at coke plants.

The efficiency of a system with separate subsystems is compared with that of an integrated system developed by means of an informational approach to system organization. The comparison is based on exergy analysis. As an example, we consider a system for commercial carbon dioxide production from flue gases at a trigeneration power plant. The trigeneration power plant combines two subsystems: a Rankine cycle for flue gas heat recovery (after the removal of sulfur and nitrogen oxides); and a refrigeration cycle with an expander for the capture and extraction of carbon dioxide as a commercial product. The exergy efficiency of the integrated system is more than twice that of the system with the components operating independently of each other. This indicates a synergetic effect, in which the overall efficiency of the system exceeds the efficiency of either subsystem.

Approaches to assessing professional risk are considered for the example of a EuroChem facility. Deficiencies in the program for professional risk assessment outlined in Russian Handbook 2.2.1766–03 are analyzed. This program takes no account of the worker’s age, experience, and overall health. Likewise, statistical data regarding workplace injuries and morbidity are ignored. At the same time, the method of calculating the individual professional risk proposed by the Klin Institute of Labor Protection and Working Conditions permits calculation of the risk for 66 workers and determination of an integral index of professional risk within the organization. Comparison of risk assessments by method in Handbook 2.2.1766–03 and the Klin method shows that the class of working conditions affects the individual professional risk but is not the determining factor.