Tetsuo Tatsumi

Development of Silicon Nitride Components for Gas Turbine

Silicon nitride is one of the most practical candidates for ceramic gas turbines. The SN282 is silicon nitride material developed by Kyocera for gas turbines. Several new technologies have been developed to achieve materialization of ceramic gas turbines, such as material, fabrication process, evaluation / analysis technology. Recent technology is focused on recession of silicon-based ceramics under combustion gas. Environmental Barrier Coatings (EBCs) are developed to suppress these recession. We have found rare-earth element silicate and yttrium stabilized zirconium oxide (YSZ) have high corrosion resistance to the combustion gas. These materials were applied to the ceramic gas turbine components. The components with EBCs were evaluated in the actual engine tests. We have confirmed that the EBCs effectively work for the recession resistance.

Development Summary of the 300 kW Ceramic Gas Turbine CGT302

Japanese Ministry of International Trade and Industry has been promoting a 300 kW Ceramic Gas Turbine (CGT) research and development program for 10 years. It was begun in 1988 as a part of the “New Sunshine Project”. The development target is to achieve thermal efficiency of over 42% at a turbine inlet temperature (TIT) of 1350°C. We have been taking a part in this project and developing a regenerative two-shaft CGT302.This project will be finished at the end of FY1998. In 1998, we confirmed 31.7 ppm NOx emission at 1350°C by engine test. This result cleared the target emission level of 70 ppm. We also achieved 40.5% of thermal efficiency at 1412°C TIT and we are working to achieve the final target and cumulating operating hours to confirm reliability of ceramic components at 1200°C TIT which is considered to be reasonable temperature for commercial use.This paper describes about ten years development summary of the CGT302.Copyright

Summary of CGT302 Ceramic Gas Turbine Research and Development Program

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. (KM) 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 multi-fuel capability to be used in co-generation systems, and 3) to demonstrate long-term operation. The targets of this program were: i) to achieve a thermal efficiency of over 42% 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% thermal efficiency, and 31.7 ppm NOx emissions (O2 = 16%) at 1350°C TIT. At this time it had also accumulated over two thousand hours operation at 1200°C.In this paper, we summarize the development of the CGT302.Copyright

Research and Development of Ceramic Gas Turbine (CGT302)

The ongoing Japanese Ceramic Gas Turbine (CGT) project, as a part of the New Sunshine Project funded by the Ministry of International Trade and Industry (MITI), aims to achieve higher efficiency, lower pollutant emission, and multi-fuel capability for small to medium sized gas turbine engines to be used in co-generation systems. The final target of this project is to achieve a thermal efficiency over 42% at a turbine inlet temperature (TIT) of 1350°C.Under this project, Kawasaki Heavy Industries (KHI) is developing the CGT302 (a regenerative twin-spool CGT). The CGT302 has several unique features as follows: simple-shaped ceramic components, KHI’s original binding system for turbine nozzle segments, stress-free structure using ceramic springs and rings, etc. In addition to these features, a high turbine tip speed and a metal plate fin recuperator were adopted.At the end of the fiscal year 1994, an intermediate appraisal was carried out, and the CGT302 was recognized to have successfully achieved its target. The CGT302 endurance test at the intermediate stage required 20 hours’ operation of the basic ceramic engine. The actual testing accomplished 40 hours at over 1200°C TIT, which included 30 hours of operation without disassembling. The target thermal efficiency of 30% at 1200°C has almost been reached, 29.2% having been achieved. In 1995 the CGT302 recorded successfully 33.1% at 1190°C of TIT with no trouble.We will introduce the current status of R&D of the CGT302 and its unique features in this paper.Copyright

Development and Evaluation of Ceramic Components for a Gas Turbine

An 8000 kW class Hybrid Gas Turbine (HGT) project, administered by the New Energy and Industrial Technology Development Organization (NEDO), was completed in March 2004. The targets of this project were improvement in thermal efficiency and output power by using ceramic components, and early commercialization of the gas turbine system. The ceramic components were used for stationary parts subjected to high temperature. It became clear that silicon nitride material showed significant recession under combustion gas. Kyocera and Central Research Institute of Electric Power Industry developed new EBCs to suppress this recession. These EBCs were evaluated by exposure test, heat cycle test and actual HGT engine test. One of the EBCs showed slight defects after the actual engine tests. However, all EBCs showed high corrosion resistance and good adhesion. It was confirmed that the all EBCs worked effectively.

CURRENT STATUS OF CGT302 (PROGRESSING TO FINAL PHASE)

In Japan, a 300kW Ceramic Gas Turbine (CGT) Research and Development program was begun in 1988 as a part of “the New Sunshine Project” promoted by the Ministry of International Trade and Industry (MITI). The final target of this program is to achieve 42% thermal efficiency at 1350°C turbine inlet temperature (TIT). Kawasaki Heavy Industries, Ltd. (KHI) has been taking part in this program developing the CGT302 (a regenerative two-shaft CGT) with Kyocera Corporation (KC) and Sumitomo Precision Products Co., Ltd. (SPP). Now the final phase of the Pilot CGT is underway. By the end of the fiscal year 1995, the CGT302 achieved 33.1% thermal efficiency at 1200°C TIT, and remarkably low NOx emissions using a premixed lean combustor equipped with a variable air valve. By January 1997, thermal efficiency was increased to 37.0% at 1282°C and fairly low NOx was recorded at 1250°C. The engine rotational speeds were reduced to avoid foreign object damage (FOD). Accordingly, the compressor, gas generator turbine (GGT), and power turbine (PT) blade airfoils were redesigned. Engine tests have been ongoing to accumulate total engine operating time and thereby confirm measured performance, access durability, and identify needed areas of improvement.Copyright