Experimental Research into Combustion of Bosnian coal to Acquire Specific Data for Design and Operation of Large Boilers

摘要

The paper deals with methodology of investigation of specific coal combustion behaviours, to support boiler design. In this work, optimization of thermodynamic conditions of PF combustion by an experimental method is presented. Special lab-scale furnace electrically heated entrained PF flow reactor is used for the experiments, with ability to change the process temperature at desire in the range from the ambient to 1560oC. Slagging and fouling assessment is based on 6-criteria evaluation of ash deposits formed into the reactor. The test points, reflecting the different types of ash deposit formed are plotted against the appropriate traditional coal indices onto graphic diagrams process temperature – traditional coal index, providing the new set of valuase of the slagging/fouling indicators. Emission indicators are formed on the base of measurements of the emission at different temperatures and for different air distribution and excess air ratios. In this way, new coal combustion behaviour predictors are formed, providing a set of data to support design the new and operation the existing large boilers based on the coal tested. In the work, results for 7 different coals are presented, namely 3 single Bosnian coals – two lignite and one brown coal, and 4 different coal blends. Using this methodology, a number of fundamental data and corelations of different parameters useful for optimization of design the new and operation the existing large boilers, are acquired. Furthermore, presented results, contributing to the filling out the world coal data base, are highly recommended to use as an indication of the combustion behaviours of those world coals which are, according to the coal and the ash chemical composition, similar to the Bosnian lignite and brown coal tested.