Summary of CGT302 Ceramic Gas Turbine Research and Development Program

Abstract

The Japanese ceramic gas turbine (CGT) research and development program (FY1988-1998) as a part of the New Sunshine Project funded by the Ministry of International Trade and Industry (MITI) was completed in March 1999. Kawasaki Heavy Industries, Ltd. (KHI) participated in this research program from the beginning and developed a twin-shaft CGT with a recuperator, designated as the “CGT302.” The purposes of this program were (1) to achieve both a high efficiency and low pollutant emissions level using ceramic components, (2) to prove a multifuel capability to be used in cogeneration systems, and (3) to demonstrate long-term operation. The targets of this program were (i) to achieve a thermal efficiency of over 42 percent at a turbine inlet temperature (TIT) of 1350°C, (ii) to keep its emissions within the regulated value by the law, and (iii) to demonstrate continuous operation for more than a thousand hours at 1200°C TIT. The CGT302 has successfully attained its targets. In March 1999 the CGT302 recorded 42.1 percent thermal efficiency, and 31.7 ppm NOx emissions (O2=16 percent) at 1350°C TIT. At this time it had also accumulated over 2000 hours operation at 1200°C. In this paper, we summarize the development of the CGT302.

Impact of heat transfer on the performance of micro gas turbines

“…The turbine polytropic adiabatic efficiency is set to 80% and a combustion chamber adiabatic efficiency of 98% is assumed. The turbine inlet temperature is set at 1175 K, which is close to the material limit of a non-cooled metallic turbine [1,4,23]. The housing is assumed to be made of 3 mm thick stainless steel 316 with a thermal conductivity of 21.5 W/mK [27] whereas the shaft and rotor are made of Inconel 601 with a thermal conductivity of 11.2 W/mK [27].…”

“…With a predicted shift to smaller micro turbines, implying lower component efficiencies and an increased impact of heat transfer, reasonable cycle efficiencies can only be obtained through an increase of the turbine inlet temperature while simultaneously limiting the impact of heat losses. Whereas significant development in material science has enabled higher temperatures to be sustained [23], the same advances have not been forthcoming in heat transfer management.…”

Small recuperated ceramic microturbine demonstrator concept

“…The lower heat exchanger gas inlet temperature associated with the selection of a higher compressor pressure ratio allowed the use of a metallic recuperator. The engine tested, designated CCGT 302 demonstrated an exceptional thermal efficiency of 42.1% (without a generator) at a turbine inlet temperature of 1350°C [17]. If the generator and frequency converter were included with say a 90% overall electrical efficiency, the thermal efficiency would have been 37.4%.…”

Experimental Assessment of a Sliding-Blade Inside-Out Ceramic Turbine

“…Since the 1970s, monolithic ceramic properties, cost as well as manufacturing processes have significantly improved thanks to many substantial development programs. With these improvements in material quality and reliability, some programs successfully tested engines above 40% thermal efficiency, but never reached the required reliability and foreign/domestic object damage resistance to become products [4][5][6].…”