D. Kamińska, S. Kamiński, KAMIKA Instruments, Warszawa, Poland

 Each process engineer in his struggle with precise definition of the grain-size distribution of the coal dust, ash, lime powder and synthetic gypsum, has to give some thought to the question, how much time need such measurements and how frequently he/she is able to repeat these measurements in order to control the process he/she operates e.g. coal combustion or flue gas desulfurization. Usually such measurements are made sporadically in relation to the bulk of material used in the process, trusting that the coal dust or lime powder have stable grain-size distribution, which assumption does not always agree with reality. Moreover the currently made measurements are always made too late. Examination results are obtained after the raw material has been applied and there is no possibility to make any grain-size corrections.