Interaction of the Temperature of Exhaust Gases and the Economic, Technical and Ecological Indices of Heat and Power Plants

Abstract

A growing competition at world power markets and a fast scientific and technical progress in the development of the alternative types of fuels expand the opportunities for Ukraine as for choice of the sources and the ways of delivery of primary power resources, power mix optimization and the reduction of hotbed gas emissions in the future. The objective of this research was to establish computation relationships between the temperature of exhaust gases and the ecologic and economic indices of heat power plant. A decrease in the temperature of exhaust gases and an efficient use of their heat for heat and power plant cycles enables an increase in the efficiency factor of the boiler and the power plant on the whole. The losses of q2, % are defined, first of all, by the temperature of exhaust gases of the boiler text, °С. It has already been established that the value of text depends on many factors (type of fuel, boiler heat surface arrangement, surface impurity degree, etc) and its choice can be made by the solution of technical and economic problem. The computations of the influence of text on q2 showed that the decrease in the temperature of flue gases by 1 °С results in the increment of the efficiency factor by 0.35 % when the natural gas is fired and by 0.06 % in the case of solid fuel combustion. An increase in the efficiency factor of the boiler of a TGMP-314A type can reach 0.7 % with no reliability degradation of the heating surface of convection trunk in the case of natural gas firing. The specific standard fuel consumption will be reduced by 1.61 s.f.g/(KW∙h). From the ecological standpoint the advantages are as follows: a drop in the temperature of exhaust gases results in a decrease of the emissions of nitrogen oxides by 250 g/GJ and carbon dioxides are reduced by 52 g/GJ. As for the TGM-96A boiler a drop in the temperature to a safe level to provide the reliability of gas escape channels of the boiler will result in an increase of the efficiency factor of the boiler by 0.14 % (the standard fuel saving is 0.32 s.f.g./(KW∙h). The emissions of nitrogen oxides and carbon oxides are reduced by 40 g/GJ and 10 g/GJ, accordingly.