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Circulating fluidized bed (CFB) boilers offer a technically viable and environmentally friendly means for the clean and efficient utilization of solid fuels. However, the complex gas–solid two-phase flow processes within them have hindered a thorough resolution of prediction issues related to coupled combustion, heat transfer, and pollutant generation characteristics. To address the deficiencies in scientific research, meet the practical operational needs of CFB boilers, and comply with new carbon emission policies, conducting full-scale field tests on large-scale CFB boilers is needed, so that the complex gas–solid flow, combustion, and heat transfer mechanisms in the furnace can be comprehended. In this paper, issues related to large-scale CFB boilers, including the uniformity of air distribution, secondary air injection range, spatial distribution of oxygen consumption and combustion reactions, distribution of pollutant generation, hydrodynamic and heat transfer characteristics, coal feeding distribution characteristics, coal diffusion characteristics under thermal operating conditions, and engineering research on anti-wear technology, are reviewed. By integrating practical engineering applications, the basic methods and measurement techniques used in full-scale field tests for large-scale CFB boilers are summarized, providing a practical reference for conducting engineering tests with large-scale CFB boilers. [ABSTRACT FROM AUTHOR]

The relevance of the study lies in the problem of calculating the bearing capacity of pile-screw foundations in the conditions of cryolithozone propagation under the influence of static pulling and pressing loads. Pile-screw foundations are a fairly new type in construction, although the first mention of them dates back to the late XVIII – early XIX centuries. This technology has proven itself from the best side. In recent years, screw piles have gained wide popularity in the construction of various facilities, but still occupy a relatively small share in foundation construction. The potential of this technology is poorly disclosed, the definition of load-bearing capacity in domestic standards is not regulated. Objective to analyze the existing methods and develop recommendations for calculating the bearing capacity of pile-screw foundations in cryolithozone conditions, comparing the results of calculations of the ultimate resistances of this type of foundation obtained by various methods with full-scale field tests and drilling piles. Methods: systematization, analysis of domestic and foreign experience in calculating screw piles in the areas of permafrost distribution; collection and processing of materials for field testing of soils with screw piles in the area of arrangement of the Bovanenkovskoe field; performing calculations of bearing capacity by various methods and comparing the results with data from field tests and drilling piles; description of the methodology for conducting field tests of piles in the conditions of the cryolithozone. Results. The authors have carried out the calculations of the bearing capacity of screw piles under cryolithozone conditions by various methods described in the literature and their comparison with the data of field tests of soils, a comparative assessment of the bearing capacity of screw piles with metal drill piles with a tip in the same geocryological conditions, revealed the advantages and disadvantages of the methods considered and various types of pile foundations. Based on the results obtained, conclusions are drawn about the possibility of using screw piles in cryolithozones and obtaining the necessary and sufficient information for their design.

Circulating fluidized bed (CFB) boilers offer a technically viable and environmentally friendly means for the clean and efficient utilization of solid fuels. However, the complex gas–solid two-phase flow processes within them have hindered a thorough resolution of prediction issues related to coupled combustion, heat transfer, and pollutant generation characteristics. To address the deficiencies in scientific research, meet the practical operational needs of CFB boilers, and comply with new carbon emission policies, conducting full-scale field tests on large-scale CFB boilers is needed, so that the complex gas–solid flow, combustion, and heat transfer mechanisms in the furnace can be comprehended. In this paper, issues related to large-scale CFB boilers, including the uniformity of air distribution, secondary air injection range, spatial distribution of oxygen consumption and combustion reactions, distribution of pollutant generation, hydrodynamic and heat transfer characteristics, coal feeding distribution characteristics, coal diffusion characteristics under thermal operating conditions, and engineering research on anti-wear technology, are reviewed. By integrating practical engineering applications, the basic methods and measurement techniques used in full-scale field tests for large-scale CFB boilers are summarized, providing a practical reference for conducting engineering tests with large-scale CFB boilers.

[Display omitted] • Field surface explosion tests of the full-scale buried pipeline were carried out. • Influence factors of pipe's dynamic response were discussed by parametric analysis. • Control standard of explosive charge for preventing pipeline damage is obtained. • Damage prediction model of pipe corresponding to different damage level are derived. Buried high-density polyethylene (HDPE) pipelines have been extremely vulnerable to terrorist attacks and third-party damage in recent years, so it is important to study the vibration response and safety criterion of buried HDPE pipelines under the action of surface blast loads. In this paper, based on the full-scale field tests, the damage characteristics of HDPE pipes under the action of surface blast loads are studied. Next, a 3D numerical calculation model was established to analyze the response characteristics of the buried pipes subjected to surface blast loads and its reliability was verified using the field monitoring data. Then, the safety of the pipes under different blast load conditions was studied in combination with numerical simulation software, and different damage models of the pipe were established based on damage theory. The results show that the peak particle velocity (PPV) of both the pipe and the surface increases as the distance from the explosive decreases, and the vibration velocity of all measurement points is dominated by the vertical direction (Y). Meanwhile, as the surface explosive is triggered, the pipe is prone to overall bending deformation in the axial direction, resulting in the destruction of the pipe. Finally, based on the comprehensive numerical calculations, numerical simulation results were obtained for different damage levels of the pipes under surface blast loading. What's more, the damage prediction model of the pipes is also proposed, and the critical curves corresponding to different damage levels are derived. [ABSTRACT FROM AUTHOR]