Recirculating transport reactors

Table 4-4 summarizes the ratings of the various reactors. The CFSTR and the recirculating transport reactor are the best choices because they are satisfactory in every category except for construction. The stirred batch and contained solid reactors are satisfactory if the catalyst under study does not decay. If the system is not limited by internal diffusion in the catalyst pellet, larger pellets could be used and the stirred-contained solids reactor is the better choice. However,... 

Figure 5-19 Recirculating transport reactor. [From V. Weekman,/l/C/i J. 20, 833,...

Adding a recirculating loop to the transport reactor, a well-mixed condition is achieved provided the recirculation rate is large with... 

This reactor gives more mechanical problems in construction and operation and is costlier than a straight-through transport reactor. It needs a recirculating pump or recirculating jet and plugging and flow problems (particularly at the bends) can be encountered. 

By recirculating the gas and catalyst tibrough the transport reactor (Figure S-19), one can achieve a well-mixed condidon provided that the recirculation rate is large with respect to the feed rate. 

Bermti et al [13], for example, used the term CFB to generically describe systems like fast fluidized bed, riser reactor, entrained bed, transport bed, pneumatic transport reactor, recirculating solid riser, highly expanded fluid bed, dilute phase transported bed, transport line reactor and suspended catalyst bed in co-current gas flow. 

Robinson and Walsh have reviewed earlier cell designs. The performance of a 500 A pilot plant reactor for copper ion removal is described. Simplified expressions were derived for mass transport both in single pass [243] and batch recirculation [244]. For a detailed discussion of the principle and the role of the rotating cylinder electrode reactor in metal ion removal the reader is referred to Refs. [13] and [241] (46 references). 

---