Shigemi Mandai

Investigation of Combustion Structure Inside Low NOx Combustors for a 1500°C-Class Gas Turbine

This paper describes the cold flow tests and low pressure combustion tests which were conducted for the development of a 1500°C-class low NOx combustion system. In the cold flow tests, the effect of vane angle and the momentum ratio of fuel to air flow on mixing characteristics inside the premixing nozzles was investigated. The stabilization of the flow field inside the combustor was confirmed by measurement of the axial velocity distribution and observations by using a tuft of soft thread.Combustion characteristics in terms of emissions and stability were investigated initially by low pressure combustion tests, and the gas temperature distribution inside the combustor was measured. NOx emissions for a 1500°C-class gas turbine as low as 50ppm at 15% oxygen at design pressure were demonstrated.Copyright

Development of Gas Turbine Combustors for Low BTU Gas

Large-capacity combined cycles with high-temperature gas turbines burning petroleum fuel or LNG have already been operated in large numbers in both domestic and foreign countries and have achieved good results. On the other hand, as the power generation technology utilizing coal burning the coal gasification combined plants are also under research. Since coal-gasified gas is lower in BTU and harder to burn than conventional fuel, development of this combustor is one of the important problems to be solved. To develop the combustor burning low BTU gas in our company, we have proceeded the study for blast furnace gas, i.e. by-product gas in the ironworks and have succeeded in practical use of the multi-can type combustor burning low BTU gas in the combined plant supplied to Chiba Works, Kawasaki Steel Corporation.

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.

Study on catalytically ignited premixed combustion

Abstract This paper describes some of the major issues related to catalytically ignited premixed combustion and the effect of pressure and velocity on the mass transfer of the catalytic reaction. The first issue is concerned with partial burning of the fuel air mixture on the catalyst surface prompting gas phase combustion to take place downstream of the catalyst layer. The latter part of this paper deals with the potential for reduced combustion efficiency from a mass transfer perspective, when going from atmospheric testing conditions to actual high pressure gas turbine operating conditions.

Methane Combustion by A Full Scale Catalytic Combustor for Gas Turbines.

The methane combustion test at atmospheric pressure was carried out by using a full scale catalytic combustor with an improved Pd catalyst for 100MW gas tur-bine. The objective is to clarify the feasibility on application of high temperature catalytic combustion to gas turbines for the LNG combined cycle power plant system. The results can be summerized as follows:1) The manufactured full scale catalytic combustor consists of a reverse annular pre-burner, an annular mixer and Pd catalyst. The dimensions of combustor is 450mm in dia-meter and 800mm in length.2) Pd catalyst showed high activity in methane catalytic combustion and the combustion reaction proceeded enough at even lower temperatures corresponded to the compressed air temperature in gas turbine systems.3) The catalytic combustor showed excellent performance in methane combustion at atmospheric pressure. The NOx emission was extremely low and the combustion efficiency was approximately 100% in wide range conditions. As a result, catalytic combustion is ex-pected to be applied to gas turbine combustors.