Purpose. The development and implementation of technologies for partial and total replacement of anthracite by domestic bituminous coal and fuel mixtures at thermal power plants of Ukraine. Methodology. Theoretical and experimental studies on the processes of combustion of coal and solid fuel biomass in the pulver ized coal flame. Industrial tests at TPPs and CHPPs. findings. Technical solutions in conditions of termination of Donetsk anthracite for combusting nondesigned fuels and fuel mixtures at 7 thermal power plants are developed. Four anthracite boilers at two thermal power plants have been converted to gas coal and got a new start, while four combined heat and power plants are being converted to such fuels. originality. Determination of kinetic characteristics of pyrolysis and combustion of coal of different metamorphism rank, of coal mixtures and solid fuel biomass, improvement of methods for calculation of the dynamics of coal and fuel mixtures combus tion in conditions of pulverized coal flame, of methods for estimation and regulation of pulverized coal inclination to spontaneous ignition and explosion. Practical value. The findings of this study have solved the strategic problem of uninterrupted energy and heat supply from TPPs and CHPPs of Ukraine in crisis conditions of interruption of Donetsk anthracite supplies due to the war actions in the East, the problem of conversion of anthracite power units to bituminous coal of domestic production with the improvement of technical, economic and environmental indicators, expanded the fuel base of TPPs which work on anthracite, and identified the ways to ef ficient use of Donetsk anthracite after Donbass reintegration. The technical solutions developed have significant prospects for further implementation.
Purpose. Development of a method and forecast estimation of sulfur dioxide emission reduction during combustion of steam coal by regulating its quality during coal preparation. Methodology. Study on sulfur content in coal using sieve, fractional analysis, analysis of ash and total sulfur content. Forecasting of sulfur content in concentrate according to the developed calculation method. Production tests at the coal preparation plant. Forecasting of the level of SO2 emissions during pulverized coal combustion according to the developed calculation method. Findings. The distribution of sulfur content of Ukrainian steam bituminous coal by size classes depending on ash content is investigated; the proximity of sulfur content to the linear dependance on the ash content of the run-of-mine coal, rock-free substance, rock and concentrate is proved. The calculations of the level of SO2 emissions during pulverized combustion of coal and its cleaned products taking into account their elemental composition is performed, and the linear dependence of the level of SO2 emissions on the total sulfur content to lower heating value (LHV) ratio is proved. Based on the obtained results, methods are developed for determining the expected sulfur content in the concentrate and the forecasted level of SO2 emissions during its combustion; the optimal depth of preparation for the coal from various mines is determined by the criterion of compliance of the SO2 emission level with the current environmental standards. Originality. Proximity of the sulfur content to the linear dependence on the ash content of the run-of-mine coal, rock-free substance, rock and concentrate is proved. The linear dependence of the level of SO2 emissions on the ratio of the total sulfur content to LHV during pulverized combustion of coal and its clean products is proved. Practical value. A method has been developed for determining the expected sulfur content in the products of coal preparation by jigging, taking into account the allowable content of the high-density fraction in the concentrate and adding dense slimes to the coal preparation products. A method has been developed for determining the predicted level of SO2 emissions during their combustion. The optimal depth of the coal preparation for coal from various mines has been determined by the criterion of compliance of the level of SO2 emissions with the current environmental standards.
Purpose. To develop scientific foundations and technical solutions and to implement the converting of the anthracite boiler of the 800 MW unit of Slovianska TPP with central coal pulverizing plant to sub-bituminous coal combustion with maximum use of existing equipment, without stopping the unit’s operation. Methodology. Theoretical and calculational studies on the processes of coal drying and pulverizing at the central coal pulverizing plant. Calculational justification of technical solutions to eliminate the risk of pulverized coal ignition in the pulverized coal supply system and in the boiler unit burners. Trial tests at the coal pulverizing plant and boiler unit. Findings. The technological features of coal pulverizing plant with steam panel dryers designed for anthracite and the peculiarities of the drying process of an individual coal particle were analyzed. It is substantiated that coal drying at the first stages takes place according to the “wet bulb thermometer” mechanism, and safe conditions for sub-bituminous coal pulverizing are determined and confirmed by tests. Technical solutions to eliminate the risk of pulverized coal ignition in the pulverized coal supply system and in the boiler burners were calculated and implemented, which allows the combustion of different coal grades (anthracite, sub-bituminous coal and their mixtures) without changing the composition of the air duct equipment and burners, using only operational measures. Originality. For the first time, it was proved that coal drying at the first stages takes place according to the “wet bulb thermometer” mechanism, and safe conditions for sub-bituminous coal pulverizing at the central pulverizing plant with steam panel dryers and unventilated ball drum mills were determined. Practical value. Technical solutions were developed and implemented to convert the anthracite boiler of the 800 MW unit of Slovianska TPP with a central coal pulverizing plant to sub-bituminous coal burning with maximal use of existing equipment, without stopping the unit’s operation, including safe modes of sub-bituminous coal pulverizing, as well as pulverized coal of various coal grades and their mixtures feeding and combustion. As a result of the implementation of the developed technical solutions, the 800 MW power unit of Slovianska TPP became the first unit in the world capable of using anthracite and sub-bituminous coal separately or in the form of mixtures of a wide range of compositions.
The paper analyzes the main properties of liquefied petroleum gas and the peculiarities of its energy use compared to natural gas, including taking into account the specifics of the operation of pulverized coal boiler units of the CHP. The advantages of liquefied petroleum gas compared to heavy fuel oil are shown and a comparative economic assessment of their use is given. It is shown that interchangeability with natural gas is ensured by mixing the vaporized liquefied petroleum gas with air to form a homogeneous mixture — synthetic natural gas, which can be directly used in burners as a direct substitute for natural gas without changes in the composition of the equipment and in the design of the boiler burners. The calculation is presented of the permissible limits of the air fraction for liquefied petroleum gas of different composition according to the criterion of the Wobbe Index correspondence of synthetic natural gas and natural gas. Technical solutions are proposed for the use of liquefied petroleum gas as a reserve and alternative fuel at coal-fired combined heat and power plants in the event of damage of gas supply networks, which provide reliable and economical feeding of a coal-fired boiler unit with synthetic natural gas in such fundamentally different modes as coal jet “lighting” with low consumption and pressure of synthetic natural gas and ignition or emergency operation at a load of 25 % with high consumption and increased synthetic natural gas pressure, with the possibility of switching from natural gas to liquefied petroleum gas and vice versa. Bibl. 17, Fig. 3, Tab. 5.
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