In which fluidized bed design does continuous circulation of solids occur?

The continuous circulation of solids is a key feature of the circulating fluid bed design. In this system, solid particles are continuously transported and circulated through the reactor or processing unit, which allows for improved heat and mass transfer.

In circulating fluid beds, a strong upward gas flow is maintained, lifting the solid particles and enabling them to circulate back down through the system. This circulation is beneficial for processes that require high throughput and better temperature control since it allows for greater contact between the gas and solids, leading to enhanced chemical reactions or heat exchange.

The effectiveness of the circulating fluid bed is particularly vital in applications such as combustion, gasification, and certain types of chemical reactors, where uniformity and efficiency in solid movement can significantly influence the overall performance of the system.

This distinguishes the circulating fluid bed from other designs, which may not support continuous solid circulation or rely on different mechanisms for fluidizing and handling solids. For instance, bubbling fluid beds are characterized by the formation of bubbles and do not inherently support continuous solids circulation as robustly as circulating fluid beds do. The fixed bed design involves stationary solids, while hybrid beds may incorporate features of both fluidized and non-fluidized systems, but do not emphasize continuous solid circulation to the same extent as circulating fluid beds