Heat Exchange and Hydrodynamic Characteristics of Unified Package of Cold Layer of RAH

Heating the air in the boiler air heater with the heat of fuel combustion products performs the functions of increasing the fuel combustion temperature, increasing the temperature level of gases in convective heating surfaces, improving ignition and fuel combustion conditions, increasing boiler efficiency by utilizing waste gas heat, improving fuel quality due to its preliminary supply, etc. However, the peculiarities of the process of heating the air in the air heaters do not allow to achieve a decrease in the temperature of the exhaust gases. This is due to the unfavorable ratio of heat capacities of flue gases and air, as well as corrosion and contamination of the heating surfaces of air heaters. The research of heat transfer processes and hydraulic resistance of unified package of cold layer of RAH is depicted at this work. The graphic dependence of the change in the coefficient of hydraulic resistance and Nu number for unified packages with single line of sheets and simplified profile with corrosion resistance enamel from the Reynolds number for different values of the length of the replaced areas was constructed. The unified packing of the simplified profile has increased by 1.17 times equivalent diameter and is characterized by good operational parameters and takes into account the risk of contamination of heating surfaces due to the enamel coating.

Capture of Pollutants from Exhaust Gases by Low-Temperature Heating Surfaces

One of the most effective methods towards improving the environmental safety of combustion engines is the application of specially prepared water-fuel emulsions (WFE). The application of WFE makes it possible to reduce primary sulfur fuel consumption and reveals the possibility of capturing the pollutants from exhaust gases by applying condensing low-temperature heating surfaces (LTHS). In order to realize such a double effect, it is necessary to investigate the pollution processes on condensing LTHS of exhaust gas boilers (EGB), especially the process of low-temperature condensing a sulfuric acid vapor from exhaust gases to investigate the influence of condensing LTHS on the intensity of pollutants captured from the exhaust gases. The aim of this research is to assess the influence of the intensity of pollutants captured from exhaust gases by condensing LTHS in dependence of water content in WFE combustion. Investigations were carried out at a special experimental setup. The processing of the results of the experimental studies was carried out using the computer universal statistical graphic system Statgraphics. Results have shown that in the presence of a condensing heating surface, the degree of capture (purification) of pollutants from the exhaust gas flow is up to 0.5–0.6.

ENERGY EFFICIENT EQUIPMENT FOR MODERNIZATION OF THE GAS BOILERS POWER 0.1-30 MW

The possibility of modernization of boilers TVH-8M, TVH-8 and NYYSTU-5, operated in Ukraine, with the increasing of their technical and economic indicators to the modern European level is shown. Projects of modernization of boilers have been developed, which consist in redesign of heating surfaces in convective shafts of existing boilers without increasing their overall dimensions with using convective part of pipes diameter 32 x 3 mm and replacement of burner devices by developed new type MPIG-3. It is shown that the results of industrial implementations achieved efficiency of boilers type TVH-8M (TVH-8) 94-96% in the operating range of their load and obtained the calculated efficiency for boilers NYYSTU-5 92-94%. It is experimentally proven that when installing special calibrated nozzle, instead of drilled holes in the collectors of gas burners, it is possible to keep the nozzle geometry (natural gas burner consumption depending on pressure) unchanged throughout the service life. The technical possibility of combustion of biogas and mixtures of natural gas and hydrogen in the slot bottom diffusion burners of the MPIG-3 type, when replacing only the nozzle apparatus is shown. Bibl. 17, Fig. 6, Table 1.

Maintenance and repair of ship boilers

The textbook shows the features of the layout and designs of ship auxiliary, recycling and combined boilers that affect their working conditions and methods of maintenance and repair. Recommendations for external inspection of boilers, control and maintenance in action are given. With examples from ship practice, the main methods of cleaning, defecation and repair of heating surfaces and other parts of various types of boilers are considered. It is intended for students of higher educational institutions studying in the specialty "Operation of marine power plants" and university teachers. It can also be useful for ship mechanics.

Integrated research of slaging intensityof the boilerunit heating surfaceswhen burning non-project fuels

THE PURPOSE. Comprehensive research of the slagging intensity is the heating surfaces of the BKZ-420-140 boiler unit with solid slag removal at the Abakan CHP when burning non-project fuels. The relevance of the work is due to the technical necessity and economic feasibility of conversion boiler units to combustion of non-design coals. METHODS. The problem has been analyzed by methodology for conducting complex tests, measurements and processing of experimental data, as well as the results of experimental and computational studies of a boiler unit when operating on coals of various qualities. RESULTS. Qualitative and quantitative parameters for assessing the properties of off-design coals and their behavior in real operating conditions of radiation, semi-radiation and convective conditions, taking into account their modes and design functions, have been obtained. CONCLUSION: A computational analysis of the operating modes of boiler units when burning non-design fuels showed that a promising technology for involving non-design coals in the fuel and energy balance of a thermal power plant is providing a scientifically based mixture of design and nondesign fuels.Analysis of the slagging and polluting properties of non-design coals makes it possible to predict changes in the characteristics of the thermal efficiency of heating surfaces and to develop many practical recommendations for optimizing the parameters of the cleaning equipment installed on the boiler.Also, mixtures of fuels were determined for which the wall temperatures of the metal of the outlet stack of the superheater increase, which significantly reduces the strength characteristics of the surface.The assessment and prediction of the reliability of the heating surface is carried out by calculating the temperature of the metal wall in the most heat-stressed place.

Electric Spark Alloying of Radiant Coils for Pyrolysis Furnaces

Currently, the petrochemical industry uses furnaces to produce ethylene, the main element of which is radiant coils designed for the decomposition of straight-run gasoline into pyrolysis gas, which is the main product for producing ethylene. In radiant coils, the gasoline decomposition process must take place at a temperature of about 800 °C with a high heating rate in order to avoid coking of the coils. Heat is supplied by radiation from the inner lining of the furnaces heated by the flame of flat-flame gas burners. For radiant heat transfer to occur, the surface of the coils must have a high degree of blackness. This article presents the developed technology for coating heating surfaces with shungite and the results of increasing their emissivity to intensify radiant heat transfer. Measurements of the emissivity after electrospark alloying were carried out by the radiation method, according to which, according to Kirchhoff’s law, the emissivity is equal to the emissivity at equal temperatures.

INCREASE OF EFFICIENCY OF WASTE-HEAT BOILERS WITHIN SELECTION OF COMPRESSOR SHOP LAYOUT

Increasing the efficiency of steam boilers is largely due to the timely cleaning of heating surfaces, which improves their steam efficiency and saves a significant amount of conditional fuel. One of the promising directions in this way is the use of pneumatic pulse technology, which ensures the production of highefficiency, safe, remotely controlled cleaning systems. The implementation of this technology involves, among other things, evaluating the composition and layout of the necessary equipment of the compressor shop, solving the problems of their optimal design.