Heat transfer mixing

Activities associated with bioreactors include gas/hquid contacting, on-hne sensing of concentrations, mixing, heat transfer, foam control, and feed of nutrients or reagents such as those for pH control. The workhorse of the fermentation industry is the conventional batch fermenter shown in Fig. 24-3. Not shown are ladder rungs inside the vessel, antifoam probe, antifoam system, and sensors (pH, dissolved oxygen, temperature, and the like). Note that coils may lie between baffles and the tank wall or connect to the top to minimize openings... 

The essential feature of a Jluidized-bed reactor is that the solids are held in suspension by the upward flow of the reacting fluid this promotes high mass and heat transfer rates and good mixing. Heat transfer coefficients in the order of 200 W/m-°C between jackets and internal coils are typically obtained. The solids may be a catalyst, a reactant (in some fluidized combustion processes), or an inert powder added to promote heat transfer. 

Figure 5-40. Liquid mixing heat transfer. Compiled by permission from References 3, 5, 6, and 22.

Oldshue, J. Y, F luid Mixing, Heat Transfer and Scale Up, Chemical and Process Engineering, April 1966, p. 183. 

Similarity for scale up, 312, 313 Dynamic, 313 Geometric, 312, 313 Kinematic, 313 Turbulence, 323 Mixing heat transfer... 

Approach well mixing Heat transfer Gas in plug-flow... 

Basically, using these technologies one would like to move forward to the theoretical optimum of a chemical process, which is that there are no other limitations than chemical kinetics. Normally a chemical process is influenced by more than just kinetics hydrodynamics (mixing), heat transfer, and mass transfer determine the quality of the process. Process intensification focuses on removing these three limitations to reaching the goal of kinetically limited processes. This is schematically depicted in Figure 2. 

More than 100 micro structured devices are listed on the homepage of the pChemTec consortium [24]. The devices cover physical applications such as flow distribution, mixing, heat transfer, phase transfer, emulsification and suspension, as well as chemical applications such as chemical and biochemical processing. Some separation units such as membrane separation and capillary electrophoresis are also offered. Control devices such as valves, micro pumps for product analysis and mass flow controllers supplement the catalog. 

Distillation Fluid Mixing Heat Transfer Steam Tables Thermodynamics... 

Atomic and Molecular Collisions Batch Processing Chemical Thermodynamics Fluid Mixing Heat Transfer... 

Fluid mechanics is the foundation of combustion. Mixing, heat transfer, or chemistry all depend on the underlying flow distribution. In turn, they affect the flow pattern. All four processes are intimately linked and interdependent. 

Physical properties for all flows are inputted. The user must specify certain parameters such as mixing models, kinetic rates, turbulence, and others as required. The CFD model is generally full-scale with complete similitude. The governing differential equations that solve all aspects of mixing, heat transfer, chemistry, turbulence, fluid mechanics, species, and continuity are iterated across the entire model until a converged solution is obtained for all cells and boundary conditions. 

Process-intensifying equipment, such as novel reactors, intensive mixing, heat-transfer and mass-transfer devices ... 

Polymers can be classified according to the techniques used during the polymerization of the monomer. In bulk polymerization, only the monomer (and possibly eatalyst and initiator, but no solvent) is fed into the reactor. The monomer undergoes polymerization, at the end of whieh a (nearly) solid mass is removed as the polymer product. As we shall see later, bulk polymerization is employed widely in the manufacture of condensation polymers, where reactions are only mildly exothermic and viscosity is mostly low thus enhancing ready mixing, heat transfer, and bubble elimination. Solution polymerization involves polymerization of a monomer in a solvent in which both the monomer (reactant) and polymer (product) are soluble. Suspension polymerization refers to polymerization in an aqueous medium with the monomer as the dispersed phase. Consequently, the polymer resulting from such a system forms a solid dispersed phase. Emulsion polymerization is similar to suspension polymerization but the initiator is located in... 

S. M. Senn and D. Poulikakos. Laminar mixing, heat transfer and pressure drop in tree-like microchannel nets and their application for thermal management in polymer electrolyte fuel cells. J. Power Sources, 130 178-191, 2004. 

Scale-up concept for modular microstructured reactors based on mixing, heat transfer, and reactor safety. Chem. Eng. Process., 50 (10), 1017-1026. 

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