Study of Bed Material Agglomeration in A Horizontal Circulating Fluidized Bed Boiler Burning Rice Husk

During combustion of potassium containing biomass, there is a risk for bed material agglomeration when using circulating fluidized bed boilers (CFB). Tsinghua University has developed a new type of CFB Boiler, a so called horizontal circulating fluidized bed boiler (HCFBB). Instead of having one high combustion chamber, it consists of three combustion chambers with low height but placed in parallel horizontally. The alkali related bed material agglomeration was studied in one of such boilers in Xiamen, China, burning rice husk. Ash samples from the bottom of the bed, from the bottom of the join part of the secondary and burnout chamber and from the cyclone have been taken and they have been studied by SEM-EDX analysis. The results show some interesting correlation among potassium, aluminum, phosphorus. The collection of deposit on heat exchange tubes in the convection section of the boiler was attempted using a deposit probe situated in the flue gas channel during combustion, however no deposit was formed