Which type of fluidized bed boiler circulates the bed materials?

A circulating bed boiler is specifically designed to allow for the continuous circulation of bed materials within the system. In this type of boiler, solids are not just fluidized and then settle; instead, they are transported through the system, enhancing the overall efficiency of fuel combustion and heat transfer.

The circulation of bed materials helps maintain an optimal temperature and ensures uniform mixing of the solid particles with the combustion gases. This results in improved combustion performance, reduced emissions, and better thermal efficiency. The ability to continuously circulate the bed materials also allows for the handling of larger and more varied types of fuel, accommodating different combustion characteristics.

In contrast, stationary bed boilers, bubbling bed boilers, and fixed bed boilers do not have this feature of continuous circulation. Bubbling bed boilers can fluidize particles, but they typically do not have the same level of continuous material circulation as found in circulating bed boilers. Thus, the defining characteristic of a circulating bed boiler lies in its design to promote the movement of bed materials, ultimately leading to a more efficient and effective combustion process.