Nobuyuki Nishiguchi

Manager GH-PT R & D Headquarters
(1-1-1 Hama, Amagasaki City, Hyogo 661 Japan)

Abstract

Waste heat energy is the most expected national energy source in Japan, which is most effectively used in the case of electric power. This paper shows current situation of technological research & development and social background in this field. WTE (Waste-to-Energy) electric power generation is not so popular in Japan because of (1)low price of electricity sold via grid line, and(2)low efficiency of power generation (10%-15%) because of high temperature corrosion of superheater tube inside waste heat boiler. For higher efficiency of WTE, several researches are now going; (1)development of super heater tube material resistant against high temperature metal corrosion; (2)cycle efficiency improvement by reheating of wet steam outlet from high pressure turbine; (3)cycle efficiency improvement by using additional fuel for superheating. We define REAL WTE EFFICIENCY as an evaluating measure of real effect of additional fuel in the case of SUPER WTE SYSTEM (additional fuel superheating system). We find that there exists an optimal point for most efficient usage of additional fuel, and that REAL WTE EFFICIENCY almost depends on steam pressure and superheat temperature. At last we show some cases of constructing SUPER WTE SYSTEMS and current movement of the regulation of the law.

Key words: unused energy, waste-to-energy, efficiency, superheater, gas turbine