Volchyn I. Development and improvement of processes of dust and sulphur dioxide removal from TPP boilers

The dissertation is devoted to the development and improvement of technologies for flue gases cleaning from dust and sulphur dioxide emissions from TPP boilers, based on the results of experimental and theoretical studies. To improve the efficiency of dry electrostatic precipitator (ESP) it is proposed to implement pre-charging of the fly ash particles before the ESP, and to implement periodic rapping of the electrodes. For wet precipitators the optimum droplet size is determined in the range 75-200 microns and to meet the requirements of European Directives it is recommended to introduce wet ESP with dust removal efficiency above 99.5%. It was proved that the rate of wet desulphurisation is determined by the interfacial mass transfer, which process is much slower than protolytic reaction in solution. The use of grinded limestone as sorbent is justified due to its high rate of absorption of sulphur dioxide and the absence of deposits of calcium sulphite. It is proved that the formation of sulphate in the solution occurs only through the hydrosulphite oxidation, while increase of the ash content in the washing liquid reduces the emissions of sulfur dioxide. The feasibility is experimentally proved, of using the grinded limestone as a sorbent in the semidry desulphurisation technology. A mathematical model is developed of the process of the hot flue gas desulphurisation by droplets with suspended sorbent. The pilot-scale dry desulphurisation plants are developed and commissioned at the steam boilers at Ukrainian TPPs. The linear approximation is obtained of the concentrations of sulphur dioxide versus sulphur and ash content as per dry basis of fuel. The technological regulations for construction of flue gas cleaning plants at Ukrainian thermal power plants are developed.