Reactors hydrodynamics

In the design of optimal catalytic gas-Hquid reactors, hydrodynamics deserves special attention. Different flow regimes have been observed in co- and countercurrent operation. Segmented flow (often referred to as Taylor flow) with the gas bubbles having a diameter close to the tube diameter appeared to be the most advantageous as far as mass transfer and residence time distribution (RTD) is concerned. Many reviews on three-phase monolithic processes have been pubhshed [37-40]. 

Evaluation of reactor hydrodynamics by measuring gas-liquid mass transfer coefficient... 

Furthermore, it is sometimes questionable to use literature data for modeling purposes, as small variations in process parameters, reactor hydrodynamics, and analytical equipment limitations could skew selectivity results. To obtain a full product spectrum from an FT process, a few analyses need to be added together to form a complete picture. This normally involves analysis of the tail gas, water, oil, and wax fractions, which need to be combined in the correct ratio (calculated from the drainings of the respective phases) to construct a true product spectrum. Reducing the number of analyses to completely describe the product spectrum is one obvious way to minimize small errors compounding into large variations in... 

A proper laboratory or process development unit (PDU) is required if there is a lack of information on the reaction mechanism, kinetics, and the reactor hydrodynamics, especially for a new reaction system (Dutta and Gualy, 2000). In laboratory experiments, certain aspects of the process are investigated by handling small amounts of raw materials to reduce the material constraints to a minimum. In these experiments, all mechanisms that do not depend on size, such as thermodynamics and chemical kinetics, can be illuminated (Trambouze, 1990). 

DOE, Slurry Reactor Hydrodynamics Studies Final Report, US Department of Commerce, National Technical Information Service, USA (DOE, 1985)... 

Evaluate the reactor hydrodynamics by determining the retention time distribution (see Levenspiel, 1972, 1999). 

Kitron, Y. and Tamir, A. (1988). Performance of a coaxial gas-solid two impinging streams (TIS) reactor Hydrodynamics, residence time distribution and drying heat transfer. I EC Research, 27 1760-1767. 

Krishna, R. (1993). Analogies in Multiphase Reactor Hydrodynamics. In Encyclopedia of Fluid Mechanics. Supplement 2. Advances in Multiphase Flow. Ed. N. P. Cheremisinoff. Houston Gulf Publishing. 

Reactive Stripping in Structured Catalytic Reactors Hydrodynamics and Reaction Performance... 

Deterministic computational methods have been applied to the description of deactivation processes [54] models also exist for inter- and intraparticlc diffusion as well as reactor hydrodynamics. For pore diffusion. 

M. L. Janex, P. Savoye, Z. Do-Quang, E. Blatchley 111, and J. M. Laine, Impact of water quality and reactor hydrodynamics on wastewater disinfection by UV, nse of CFD modeling for performance optimization. Water Science and Technology 38(6), 71-78 (1998). 

On-going research is focused on various aspects starting from improving the reactor hydrodynamics to the catalyst development. Several new reactor designs (Fig. 2) with possibilty of scale-up are available (38 0). An improved reactor design is recently published where reactor perfromace is improved by inducing Taylor-Couette flow (41). 

Reactor hydrodynamics and modeling are complex. Scale-up and design thus presents serious challenges which limits the use of these reactors to applications that can justify the significant research and development efforts involved. 

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