The first chapter presents an analysis of the fleet, technical condition of TPP and CHPP boiler units, of small and medium-sized boilers, as well as their potential fuel base, identifies the main types of boiler units that should be converted to available domestic solid fuels, and substantiates the purpose and objectives of the research. The second chapter contains findings in the main trends in the redistribution of heat generation and heat perception across the elements of boiler plants converted to other types of fuel, calculations of the adiabatic combustion temperature and the share of fuel heat carried to the convective pass of the boiler dependence on the specific volume of solid fuel combustion products, and the proposal to use this value as a criterion for the possibility of converting dense bed boilers from coal to biomass. The third chapter is devoted to the development and calculation justification of
technical solutions for the deep reconstruction of TPP boiler units, in particular, the replacement of pulverizing systems with an intermediate pulverized coal hopper with pulverizing systems with direct pulverized coal injection into the burners, the reconstruction of 300 and 800 MW gas-oil boiler units with their conversion to bituminous coal, and organisation of co-combustion of biomass and coal in pulverized coal boilers at TPPs and CHPPs. Chapters 4 and 5 present the calculation-based and practically implemented
technical solutions for the conversion of anthracite boilers at TPPs and CHPPs to bituminous coal combustion, and for the conversion of anthracite and gas-oil boilers of small and medium capacity to bituminous coal and biomass. The dissertation is the first to prove by calculations and to experimentally confirm that when anthracite boilers are converted to burning bituminous coal, the furnace temperature decreases due to an increase in the volume of combustion products, including flue gas recycling for fuel drying, and a decrease in hot air consumption. This leads to an increase in heat removal from the furnace, which changes the heat transfer rate of the convective heating surfaces of the boiler and must be taken into account when developing technical solutions for converting boilers to bituminous coal, and to reduction in thermal nitrogen oxides generation. For pulverized coal boilers, for the first time, a power limitation was found for the conversion from anthracite to bituminous coal combustion due to an increase in the specific volume of bituminous coal combustion products compared to anthracite, as well as the temperature and, accordingly, the volume flow rate of flue gases, which should be taken into account when calculating their expected technical and economic indicators. For the first time, the possibility and conditions for organising the combustion of hard coal with different volatile yields, with the conversion from gas group coal to anthracite or vice versa by adjusting the operating parameters only, have been proved and found. For the first time, the criterion for the possibility of dense bed boilers converting from coal to biomass based on the specific volume of combustion products is substantiated and it is found that the condition for such conversion is the redistribution of heat transfer in the convective pass towards an increase in the economiser and a decrease in the air preheater. For the first time, the effect of abrasive cleaning of heating surfaces of dense-layer boilers from biomass ash deposits when alternate or co-combustion of biomass with coal was experimentally found. The practical significance of the results obtained is determined by the fact that the study developed and proved by calculations technical solutions for the reconstruction of gas-oil boilers TGMP-314 and TGMP-204 of 300 and 800 MW power units of Trypilska and Zaporizka TPPs with their conversion to bituminous coal, for the conversion of anthracite boiler units TPP-210 and TPP-210A at 300 MW of Zmiivska TPP to bituminous coal, for the organisation of co-combustion of fuel biomass with coal in the pulverised coal boiler unit TPP-210A at Tripilska TPP, typical technical solutions for conversion of anthracite boiler units at CHPP plants with steam capacity from 90 to 250 t/h to bituminous coal burning. It were developed, calculated and practically implemented the technical solutions for the conversion of three anthracite boilers TPP-210A of 300 MW power units of Trypilska TPP to bituminous coal, of an anthracite boiler unit TPP-200-1 at 800 MW of Slovianska TPP to burn bituminous coal and fuel mixtures with different volatile matter yields, of anthracite boiler units with a steam capacity of 220 t/h of Darnytska CHPP to burn bituminouscoal under martial law, of dense bed anthracite boilers to burn bituminous coal and biomass, and for gas-oil boilers of the BKZ-75GMA type reconstruction to burn bituminous coal and biomass pellets on a chain grate.
