This article is the second part of our study devoted to a comprehensive analysis of bitumen-mastic insulation coatings (BMIC) used on steel underground distribution gas pipelines in the Republic of Belarus. Given the achievement of long service life, the influence of the technological stage (production of bitumen and mastic, pipe insulation works) on the current condition of the coatings has been completely exhausted, and the operational stage is the determining factor. The relationship between soil and subsoil conditions and the key features of operational aging of BMIP has been revealed, i.e. a combination of limited access to molecular oxygen and a moderate temperature regime (low rate of oxygen oxidation), the possibility of biocorrosion of bitumen and polymeric coating components, and the combined effects of soil moisture (hydrolysis, the Rebinder effect, oxygen and catalyst transport) and continuous mechanical impact from soil with the inclusion of moisture. The mechanism of operational destruction of BMIP is revealed, which consists in the accumulation of internal stresses, degradation of the physical-chemical and rheological properties of the mastic material, and its subsequent destruction under the influence of ground loads. The functional failure of the coating consists in the loss of its barrier and dielectric properties, and the formation of physical and electrical contact between the ground electrolyte and the metal surface of the pipe. The impact of plasticizing additives on the durability of bitumen mastics and, consequently, on the durability of bituminous insulation coatings is considered. It has been established that along with the positive effect of expanding the temperature range of bitumen materials used in pipe insulation work, the introduction of petroleum plasticizers in the form of industrial oils further reduces the stability of the bitumen matrix, promotes accelerated aging and the development of defect formation of BMIP (loss of cohesion, cracking, etc.) at the operational stage.

The State Program of the Republic of Belarus “Sustainable Energy and Energy Efficiency” for 2026–2030 envisages the maximum possible use of heat pumps in centralized and decentralized heat supply systems. The main factors facilitating the use of Heat Pump Units (HPUs) in conjunction with thermal energy storage technologies are the possibility of utilizing the lowtemperature heat sources, increasing the maneuverability of the power system in conditions of a high proportion of electricity generation from renewable energy sources and nuclear power plants, and reducing emissions of harmful substances. The article discusses the circumstances and technical solutions for integrating high-capacity HPUs into heat supply systems. To date, the share of highcapacity HPUs in the generating capacity structure of District Heating Systems (DHS) remains insignificant in global practice; however, in a number of countries their widespread application in the near future is considered as part of energy decarbonization programs. The authors discuss the technical aspects of integrating HPUs into existing DHS using various sources of low-potential heat, examine the application of different types of working fluids, and analyze the financial costs of project implementation. It is shown that the widespread deployment of HPUs is constrained by high capital costs, the uncertainty of the formation of electricity tariffs and the uncertainty of information about the efficiency of equipment at variable loads. Under these conditions, projects of HPUs implementation in the DHS cannot be regarded as model solutions, they require the use of individual design solutions for each specific case. The results of the analysis of technical solutions of projects implemented to date for the use of high-capacity HPUs in the DHS demonstrate the technical feasibility and economic expediency of using high-capacity HPUs in the territory of the Republic of Belarus in the presence of an economically acceptable source of low-potential heat.

Investigating the rheological behavior and mechanisms of structure formation in disperse systems based on organic binders is a critical task for optimizing energy consumption during the production and operation of viscoplastic petroleum products. The objective of this study is to improve the methodology for evaluating the rheological properties of such systems, accounting for their complex internal structure. Based on an extensive dataset obtained from rotational viscometry, a comparative analysis of flow curve approximation accuracy was performed using the Ostwald – de Waele, Shvedov – Bingham, Casson, and Herschel – Bulkley models. It is shown that the application of simplified power-law relationships leads to a substantial overestimation of the yield stress (up to 1000 %) and a misinterpretation of viscous resistance as static structural strength. The effectiveness of the three-parameter Herschel – Bulkley model is substantiated as the most reliable tool for describing the behavior of viscoplastic media (coefficient of determination > 0.99). It is established that the mineral filler acts as a thickening agent without forming a coherent load-bearing framework, even at high concentrations. The percolation mechanism of system reinforcement by cellulose fibers is confirmed, whereby a spatial reinforcing cluster is formed at fiber contents above 2.5 %. The developed empirical model, which describes the yield stress as a cubic function of fiber content and a linear function of polymer content, is recommended for the targeted regulation of the rheological properties of disperse systems. The obtained results ensure the rational use of expensive components and enhance the energy efficiency of production processes and the operational reliability of materials based on organic binders.

Nowadays, such areas of biomass processing as pyrolysis, gasification, and liquefaction continue to be improved in industrialized countries. Among modern technologies for the energy use of plant biomass, thermochemical conversion by pyrolysis is the most versatile, efficient, and cost-effective. A promising area for the development of the energy sector in the Republic of Belarus is the widespread use of wood biofuels, while the most promising one is oxygen-free thermochemical conversion of biomass. The development and implementation of new energyefficient equipment for the thermochemical conversion of wood biomass will provide a reduction of energy dependence and mitigate of the negative impact of the country's energy sector on the environment. The use of it in an amount not exceeding its annual increase is neutral with respect to carbon dioxide emissions into the atmosphere, which contributes to reducing emissions of this greenhouse gas, and therefore corresponds to the solution of preventing an environmental catastrophe on the planet. Pyrolysis makes it possible to obtain high-quality, environmentally friendly solid, liquid and gaseous fuels from almost any raw material containing organic hydrocarbon components. One of the significant disadvantages of the thermochemical conversion of biomass is the formation of large amount of carbon dioxide, which under certain conditions can account for up to 50 % of the volume of the gas being obtained. This results in a low calorific value of the thermochemical conversion products, significantly reducing the efficiency of the process. Biomass is a neutral fuel in terms of the CO2 balance in nature. However, to increase the specific heat of combustion of fuel gases, CO2 removal is necessary. In addition to increasing the heat of combustion, CO2 removal reduces transportation costs and protects pipelines from corrosion. Complete CO2 removal from fuel gases can significantly increase their calorific value.

The work is devoted to the implementation of current plans for import substitution and improving the efficiency of the energy sector of the Russian Federation. The study aims to substantiate the initial steam parameters in double-circuit combined-cycle heating plants with a promising domestic gas turbine installation GTE-65. The indicator of relative fuel savings in combined energy generation in comparison with separate energy generation was used as a criterion. A simulation model for analyzing the effect of fresh steam in high- and low-pressure circuits on the efficiency of double-circuit combined-cycle heating plants has been developed on the basis of United Cycle CAD. The model allows analyzing the pressure ranges of fresh steam for circuits: for the high-pressure circuit – from 10 to 18 MPa; for the low-pressure one – from 1.0 to 2.0 MPa. It has been established that increasing the steam pressure in the double-circuit combinedcycle heating plants based on the promising GTE-65 installation from the traditionally accepted 7–8 MPa for condensation profile installations to 15–17 MPa provides a total relative fuel saving of 38.0–38.1 %. An increase in steam parameters in the low-pressure circuit from the traditional value of 0.5–0.8 to the level of 1.3–1.5 MPa also makes it possible to improve fuel savings. Practical recommendations on the use of subcritical steam pressure parameters are proposed, based on operational experience and taking into account technical limitations of existing equipment.

In the context of the introduction of cross-border carbon regulation (CBAM) in Europe and the need to improve the energy efficiency of the Russian economy, the transition to a circular model in the energy sector is becoming not only an environmental but also an economic task. However, the absence of indicators of the closure of flows of carbon, heat and waste in open statistics does not allow us to assess Russia’s real readiness for such a transition. The purpose of the study is to identify the degree of readiness of the Russian energy sector for the circular model based on statistical data for 2004–2024, identify key barriers (including statistical ones) and propose measurable indicators for managing the transition. The following techniques were used in the work: descriptive statistical analysis of time series of primary energy consumption and CO2 emissions; Pearson correlation analysis for five-year intervals; trend extrapolation method for forecasting up to 2030; comparative analysis of three technological alternatives (CCUS/EOR, CCU, and renewable energy sources) according to six criteria; a system-functional analysis of statistical gaps; reviewing of 23 scientific sources and official industry reports. Over the past twenty years, the total consumption of primary energy in Russia has increased by 16 % (from ~541 to ~630 million tons of oil equivalent), while the consumption structure has remained virtually unchanged: gas – 44–46 %, oil – 22–24 %, coal – 16–18 %, nuclear and hydropower – 13–15 %, renewable energy – less than 1 % (1.25 % in electricity consumption, according to 2025 data). The correlation between energy consumption growth and CO2 emissions decreased from +0.85 (2004–2008) to +0.15 (2019–2023), indicating a break in the direct association, but absolute emissions remained stuck in the range of 1.55–1.65 million tons of CO2 per year. The production of “new” renewable energy generation in the first nine months of 2025 decreased by 2.7 % compared to the same period in 2024, and its share does not exceed 1.25 %. In Russian statistical databases (including statbase.ru) there are no key circular indicators, viz. the volume of CO2 captured, the volume of CO2 injected into reservoirs, the volume of CO2 used as raw materials, detailed monthly dynamics of renewable energy sources, replaced volume of fossil fuels, investments in circular projects. It is concluded that the Russian energy industry has successfully severed the association between consumption growth and emissions growth, but has not switched to a circular model; the achieved stabilization of emissions has been provided by linear methods (increasing energy efficiency, replacing coal with gas) rather than by closure of carbon flows. Without the introduction of six new statistical indicators and scaling of CCUS projects and renewable energy sources, Russia will remain in the “1.6 million tons trap”, i. e., in a state in which emissions do not increase, but do not decrease absolutely.