Takero Fukudome

Development and Evaluation of Ceramic Components for Gas Turbine

An 8000 kW class Hybrid Gas Turbine (HGT) project, administered by the New Energy and Industrial Technology Development Organization (NEDO), has been ongoing since July of 1999 in Japan. Targets of this project are improvement in thermal efficiency and output power by using ceramic components, and early commercialization of the gas turbine system. The ceramic components are used for stationary parts subjected to high temperature, such as combustor liners, transition ducts, and first stage turbine nozzles. Development of the gas turbine is conducted by Kawasaki Heavy Industries, Ltd. (KHI), to achieve the Turbine Inlet Temperature (TIT) of 1250°C, thermal efficiency of 34%, NOx emission less than standard regulation values, and 4,000 h engine durability. Kyocera is in charge of the development and evaluation of the ceramic components. Recently, recession of the Si based ceramic materials under the combustion gas is the focus of attention to improve the reliability of ceramic components for gas turbine. For the HGT project, the silicon nitride material (SN282 : silicon nitride material produced by Kyocera Corporation) is used for the components subjected to high temperature. The SN282 was evaluated under the combustion gas, and clear recession was observed. Our technology of the Environmental Barrier Coating (EBC) is under development to obtain reliable heat resistive SN282 components, against the recession by combustion gas. Reliability of the SN282 with EBC has been evaluated by exposure and hydrothermal corrosion test. Ceramic components made of SN282 with EBC will be also evaluated by a proof engine test of 4,000 h, which starts in the spring of 2002.Copyright

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 and Evaluation of Ceramic Components for 8000-kW Class Hybrid Gas Turbine

An 8000 kW class hybrid gas turbine (HGT) project, administered by the New Energy and Industrial Technology Development Organization (NEDO) and sponsored by the Ministry of International Trade and Industry (MITI), has been started in July 1999 in Japan[1]. The target of this project is improvement in thermal efficiency and output power by using ceramic components, and earlier commercialization of the gas turbine system. Ceramic components are used for stationary parts subjected to high temperature, such as combustor liners, transition ducts, and first stage turbine nozzles. The gas turbine development was conducted in cooperation with Kawasaki Heavy Industries, Ltd. (KHI).Kyocera started a study on fabricating the ceramic HGT components after evaluating their shape, placement, and fabrication methods. For these ceramic components, we are using the SN282 silicon nitride material developed and used for ceramic gas turbine components in the previous ceramic gas turbine project (300kW CGT)[2-4]. We have started to accumulate the strength evaluation data, using test bars cut from the aforementioned components, and begun long term tensile creep testing to confirm the reliability of the ceramic components.Copyright

Impact Fracture Behavior of Turbine-Grade Silicon Nitride Ceramic Under Tensile Stress at Elevated Temperatures

A series of particle impact tests was carried out at elevated temperatures up to 1400°C and under tensile stresses up to 200 MPa using a gas turbine-grade silicon nitride (SN282-Kyocera Corporation). It was found that: 1) At room temperature, 100 MPa tensile stress brings 8% strength degradation. 2) Regarding the effect of the temperature without applying tensile stress, similar to the case of quasi-static loading, the fracture toughness seems to play a predominant role under the dynamic loading also. 3) At 1350°C under 100 MPa tensile stress, effect of the stress on the degradation increases by 15%. 4) The effects of temperature and tensile stress on the strength degradation seem to be additive for temperatures up to 1350°C. Above 1350°C, remarkable strength degradation appears.© 2005 ASME

Development of the 8000 kW Class Hybrid Gas Turbine

Based on the successful result of the Japanese national project for 300 kW class ceramic gas turbine development (this project was finished in March 1999), the New Energy and Industrial Technology Development Organization (NEDO) contract project “Research and Development on Practical Industrial Co-generation Technology”, funded by the Ministry of Economy, Trade and Industry (METI), started in August 1999. This project is a five-year plan until the end of the 2003 fiscal year. The objective of this project is to encourage prompt industrial applications of co-generation technology that employs a hybrid gas turbine (HGT; using both metal and ceramic parts in its high-temperature section) by confirming its soundness and reliability. The development activities are performed through ceramic material evaluation test and long-term operation test for the HGT of the medium size (8,000-kW class). It is expected that the development can realize low pollution and reducing the emission of CO2 with highly efficient use of energy. To grasp the material characteristic of the ceramic, the tensile creep rupture test, cyclic fatigue test, sub-critical crack growth test, and exposure test had been carried out. Sub element tests, such as Sector Model Text and Pre-test were carried out prior to the operation study. The operation study was started in the 2002 fiscal year. The operation tests to 5/8-load (about 5,000-kW) had been carried out as of February 2003. This paper gives the progress of the developments of the HGT.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.