Optimization of Gas Nozzles Geometry in Dual-Fuel Burners of Power Stations

Thermal power required by boilers in steam power stations is supplied through gas or heavy oil fueled burners. Incorrect functioning of these burners results, on one hand, in their inability to supply the utility's needed steam and, on the other hand, in imposing damages to various parts of the boiler and burner's structure itself. The present paper investigates problems related to the burners used in the boilers of Shazand 325 MW power station in Arak. Gas-fueled nozzles of these boilers had suffered burns, so that a large number of them would have to be either repaired or replaced in every six-monthly maintenance cycle. These difficulties are caused partly by design errors and partly by incorrect commissioning of these burners. In this paper, the burners' faults are investigated from the following viewpoints: (1) Statistical assessment of failures. (2) Investigation of trend in the nozzles failure and microstructure changes during operations. (3) Calculation of nozzles temperature when using heavy oil and natural gas fuels. Investigations leading to solutions providing new designs for nozzles in this paper and later evaluation of temperature of the new nozzles in various conditions using natural gas and heavy oil fuels have been carried out.