Kuniaki Aoyama

Development Study of 1500°C Class High Temperature Gas Turbine

This paper outlines the development programs of the next generation, 1500°C Class, high efficiency gas turbine. Combined cycle thermal efficiency of more than 55% (LHV) is expected to be obtained with metallic turbine components. To accomplish this, advancements must be made in the key technologies of NOx control, materials and cooling.Copyright

Advanced Gas Turbine Diagnostics Using Pattern Recognition

Power plant owners require their plants’ high reliability, availability and also reduction of the cost in today’s power generation industry. In addition, the power generation industry is faced with a reduction of experienced operators and sophistication of power generation equipment. Remote monitoring service provided by original equipment manufacturers (OEMs) has become increasingly popular due to growing demand for both improvement of plant reliability and solution of experienced operator shortage. Through remote monitoring service, customers can benefit from swift and appropriate operational support based on OEM’s know-how. Before implementation of remote monitoring, the customer and OEM often required repeated interchanges of information about operation and instrumentation data. These interchanges took a lot of time. Data analysis and estimation of deterioration were time-consuming. Remote monitoring has enabled us, OEMs, not only to access to a plant’s real-time information but also to trace the historical operation data, and therefore the required time of data analysis and improvement has been reduced. Mitsubishi Heavy Industries, Ltd. also embarked on around-the-clock remote monitoring service for gas turbine plant over a decade ago and has increased its ability over time. At present, the application of remote monitoring systems have been extended not only into proactive maintenance by making use of diagnostic techniques carried out by expert engineers but also into building a pattern recognition system and an artificial intelligence system using expert’ knowledge. Conventional diagnostics is only determining whether the plant is being operated within the prescribed threshold levels. Pattern recognition is a state-of-the-art technique for diagnosing plant operating conditions. By comparing past and present conditions, small deterioration can be detected before it needs inspection or repair, while all the operating parameter is within their threshold levels. Mahalanobis-Taguchi method (MT method) is a technique for pattern recognition and has the advantage of diagnosing overall GT condition by combining many variables into one indicator called Mahalanobis distance. MHI has applied MT method to the monitoring of gas turbines and verified it to be efficient method of diagnostics. Now, in addition to the MT method, automatic abnormal data discrimination system has been developed based on an artificial intelligence technique. Among a lot of artificial intelligence techniques, Bayesian network mathematical model is used.Copyright

Development and Testing of the 13MW Class Heavy Duty Gas Turbine MF-111

A new 13 MW class heavy duty gas turbine “MF-111” with the combustor outlet temperature of 1250°C (1523 K) was developed and tested.The thermal efficiency of MF-111 is designed to be 32% for simple-cycle and 45% in combined-cycle operation.MF-111 has single-shaft configuration, 15-stage axial flow compressor, 8 cannular type combustors and 3-stage axial flow turbine.Advanced cooling technology was incorporated for the turbine and the combustor design to be capable of higher combustor outlet temperature.The prototype was shoptested at full load in April, 1986. The performance and the metal temperatures of hot parts were confirmed to well satisfy the design goal. The first machine of MF-111 started the commercial operation from August, 1986 and has logged satisfactory operations.© 1987 ASME

Development of Ultra Low NOx Combustor with Catalytic Pilot Flame for Gas Turbine.

Low NOx combustion technologies for gas turbines, such as lean premixedflame combustion, have been developed and used for commercial gas turbines to meet stringent NOx regulations. However, lower NOx is required for themore severe regulations in some areas.For developing a practical catalytic combustor, intensive studies have been carried out for the screening of a favourable catalyst, the optimization of monolith sizes, the research of pressureeffects on performances and the confirmation of the effectiveness of a catalytic pilot flame.With these results, an ultra low NOx combustor for a gas turbine, which is based on a catalytic pilot flame and a lean premixed main flame, has been developed and achieved NOx of less than 10 ppm on high pressure combustion tests.High temperature gas, produced by catalytic combustion, is used as a pilot for flame holding of premixed main flames. This manner of combustion has some advantages compared with previous combustion technologies. These advantages are, besides less NOx from catalytic pilot than from diffusion flame pilot, less pressure drop on the setting catalytic pilot in parallel with main flames and high reliability by using smaller catalyst.The catalyst endurance tests are now under being carried out for the practical applications of this ultra low NOx combustor for gas turbines.