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Show Abstract 1 Development of Supplementary Firing Burner for Gas Turbine Repowering system Yoshihiro Kokura Yuichi Ichiraku Masahiko Matsumura Osaka Gas Company,Ltd. Toshio Yoshida Volcano Company, Ltd. The so-called industrial repowering system, which is to introduce gas turbine into the existing boiler-steam turbine system, is excellent in saving energy as well as cost effective due to minimum renovation of existing system. The main objective of this development is to get maximum firing capacity per turbine exhaust, to reduce NOx, to fire stably by exhaust of low oxygen concentration or fresh air interchangeably, and to fabricate the system at low cost. Our developed burner has stable firing range with exhaust whose 02 concentration is 14 - 21% and temperature is 350 - 600°C, and enables remaining 02 concentration to reduce to less than 3% (dry) without providing additional air. We divided the exhaust entering part of the burner into two stages and this burner can be also operated with fresh air at the regular inspection of the gas turbine. NOx of this burner is less than 50 ppm (02 0%) at 500°C of exhaust temperature and 15% of 02 concentration. It was proved that, NOx emission under the maximum load is in the linear correlation with the theoretical flame temperature. To reduce further NOx emission, steam injection and two-stage combustion are effective. 1. Introduction In Japan co-generation systems has been increasing and total capaci ty of natural gas fired industrial gas turbine installed gets to 346,000 kW. For wide spread of co-generation system, we need to increase the efficiency of the system and to decrease the initial cost for the system. The industrial repowering system, which is to introduce gas turbine into existing boiler-steam turbine system, is excellent in saving energy and effective in initial cost due to minimum renovation of existing system. However, this system has not widely used yet. In Fig. 1, a flow chart of typical repowering system is shown. For CASE 2, air is mixed into turbine exhaust gas to have more stearn generation capacity than CASE 1. Typical power generation capacity of gas turbines for industrial repowering system is 3,000 to 6,000 kW. It is necessary to develop the exhaust gas supplementary firing burner applicable to the power boiler having capacity of 40 T / h to 100 T / h. Because NOx emission is strictly regulated, it is required to decrease the cost for the system and to reduce generation of NOx. emission. |