The Features of the Steam Temperature Change of CFBB

Abstract

The PC fired boilers (PCB) can maintain steam temperature at setpoint between 70% and 100% MCR but the CFB boilers (CFBB) can do it between 50% and 100% MCR. What make the CFBB possess excellent steam temperature control performance? There are many differences about steam temperature control between CFBB and PCB. The steam temperature of CFBB is associated with many factors. The first is the configuration of boilers such as the configuration and arrangement of separators, the section area of furnace, the arrangement of secondary air(SA) ports etc.. The second is the fuel property, including their heat value, content of moisture, ash and sulfur, the property of ash, including its strength, size etc. The third is the parameters of boiler operation, such as the inventory of bed, the ratio of primary air(PA) to SA, the excess air, the ratio of upper SA to lower SA etc.. This paper analysises the reasons of CFBB possessing excellent steam temperature control performance and the feature of steam temperature change of CFBB.