The widely held supposition that the residence tnne dlstrlbutlon of a recycle system always approaches that of an Ideal mixer in the limit of htgh recycle rates has been disproved Physically plausible systems exist whtch vlolate both sufficiency condtttons of Buffham and Nauman [l] Limiting distrlb
The limiting residence time distribution of continuous recycle systems
โ Scribed by Michael Rubinovitch; Uzi Mann
- Publisher
- Elsevier Science
- Year
- 1979
- Tongue
- English
- Weight
- 862 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0009-2509
No coin nor oath required. For personal study only.
โฆ Synopsis
The hmltmg residence hme dlstrlbuhon (RTD) of contmuous recycle systems as the recycle ratlo approaches mlimty IS consldered It IS shown that the RTD converges to the exponential dtstrlbutlon whenever the system does not consist of a "dead volume" at the hnut Thus hmltmg behavior IS independent of the system configuratlon and flow patterns Issues concemmg the proper modeling approach and the mathematical formulatton of the condition that the system has no "dead volume" are discussed m detiul Some examples lllustratlng the importance of selecting the proper modehng approach are also provided Madison 1973
๐ SIMILAR VOLUMES
The residence-time density function for a recycle system usually tends to exponential form, with mean equal to the ratio of the volume to the volumetric flow-rate, when the recycle rate is increased at constant throughput. Two conditions each suffidient to guarantee this behaviour are: (i) that the
Equations are presented for the residence time distribution in recycle systems with crossmixing between the forward and recycle streams. The use of the method of moments to obtain the system parameters, the crossflow and recycle rates, is described and the implications of the limits of the model are