Dependence of the Temperature of Effluent Gases of the Boilers on a Change in the Loading of Thermal Power Plants

Abstract

One of the efficient methods of inexpensive modernization of thermal power plant is to reduce the temperature of effluent gases of the boilers (t exh ). The purpose of this paper was to carry out the experimental computation investigation of a degree of influence of the operation mode and performance factors (feed water flow rate and temperature, electric and thermal power) on the temperature of effluent gases of the boilers with the retention of the longevity of gas escape ducts. The attempts made to reduce the temperature of effluent gases in order to increase an efficiency factor of the boilers are restricted by the influence of (t exh ) on the longevity of heating surfaces both of the convective ducts and the entire gas-air duct (air heaters, gas-air mains, and the smoke pipe), taking into consideration the dew point (t d ) at which the combustion gas moisture condensation is possible. Based on the analysis of performance indices of the steam boilers of a ТGМP-314А type the regression equation was formed. The research data prove that the feed water temperature produces the greatest influence on the temperature of combustion gases in the entire range of variation in the electric load of the unit. The analysis of obtained data showed that the temperature of exhaust gases is increased with an increase in the electric power to 130 °С. This allows us to decrease the temperature of combustion gases on average by 20 °С taking into consideration the reliability of convective heating surfaces. Computations of the influence of t exh on q 2 showed that with the 1°С drop in the temperature of combustion gases an increase in the efficiency factor of the boiler reaches 0,035 % for the natural gas burning and 0,06 % for the fuel oil burning. Thus, we can come to a conclusion that the efficiency factor of the boiler of a ТGМP-314А type can be increased by 0,7 % with no degradation of the reliability of the heating surfaces of convective duct for the natural gas burning. The specific consumption of standard fuel will be reduced by 1,61 g.s.f. (grams of the standard fuel)/(kw∙h).