IMPLEMENTATION OF A MODERN LOWNOX FIRING SYSTEM FOR BITUMINOUS COAL INTO A NEW TAYLOR-MADE BOILER CONCEPT CONSIDERING BOUNDARY CONDITIONS OF AN EXISTING PLANT

摘要

The requirements for future concepts and modern steam generators are getting higher and more diverse. This concerns the emission values as well as other conditions such as investment costs, site conditions and boiler geometry. Depending on the coal quality NOx-emissions can be achieved with Low NOx combustion systems of the newest generation of significant less than 400 mg / Nm (tr., 6% O2). However, the design of the combustion chamber of the steam generator has always to be considered. Based on a concrete project for the replacement of an existing steam generator, the various boundary conditions are presented, which require to bring the needs of the furnace and the steam generator in line. A reconciliation between the firing system and the steam generator is indispensable. The higher the requirements, the better the interface between the firing system, steam generator and existing plant must be smoothed. The following boundary conditions are taken into account: - Existing boiler house; - Limited floor space and height; - Fuel range; - Slagging of coal; - Compliance with emission values; - Boiler efficiency; - Part load operation; - Different suppliers for the steam generator and the firing system. With a common approach of boiler manufacturer and supplier of firing system, already in the planning phase, an optimal steam generator concept is created. In compliance with the emission levels and other boundaries a solution is worked out. The solution goes to the limits of the previous experience and guidelines. As a result it can be stated that only a joint consideration of firing system and steam generator lead to an optimal solution of the task and to the satisfaction of the operator.