Abstract: The particle size distribution of limestone produced by limestone preparation system(LPS) directly influences the control of furnace desulphurization and the utilization ratio of limestone. The fine crushing and screening are the keys of the LPS to control the particle size. To effectively control the particle size and reduce the production costs, more and more plants with circulating fluidized bed (CFB) boilers choose to build their own LPS instead of purchasing limestone. In this paper, based on the engineering practice, the equipments for limestone crushing and separation are introduced. The focus is on the analysis of the technical and economic performance of three different LPSs, i.e. AUBEMA crusher + vibrating screen, column mill + PL type powder separator and the crusher fabricated by FAM. The study indicates that the LPS of column mill equipped with PL type powder separator has better economic performance, higher unit output, less moisture sensitivity and lower maintenance requirement. Therefore, it is a reasonable choice for the LPS of large scale CFB boilers.

Key words: circulating fluidized bed, desulphurization, limestone preparation