Mixing heating

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... 

Impeller Type Horsepower (Op. cost mix. heat added) N rpm Torque Initial cost... 

For thermoset-matrix materials, heat is usually added as a catalyst to speed the natural chemical reaction of polymerization. Two-part epoxies, such as found in your local hardware store, consist of a tube of epoxy and a tube of chemical hardener that react when mixed. Heat... 

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... 

For mixtures of liquids and for solutions, the heat of mixing (heat of solution) may be significant, and so must be included when calculating the enthalpy of the mixture. 

In a chemical process, the transformation of raw materials into desired chemical products usually cannot be achieved in a single step. Instead, the overall transformation is broken down into a number of steps that provide intermediate transformations. These are carried out through reaction, separation, mixing, heating, cooling, pressure change, particle size reduction or enlargement. Once individual steps have been selected, they must be interconnected to carry out the... 

The Ru3(C0)- 2 Y adducts are similarly prepared both through impregnation (solvent cyclohexane) or dry mixing (heating at 90°C under vacuum. 

The liquid in the tank is assumed perfectly mixed. Heat is added at a rate Q to hold the desired pressure in the tank by vaporizing the liquid at a rate W (mass per time). Heat losses and the mass of the tank walls are assumed negligible. Gas is drawn off the top of the tank at a volumetric flow rate F . F is the forcing function or load disturbance. 

When azeotropic distillation is used for toluene, the solvent used is usually a mixture of methyl ethyl ketone (MEK) and water (10%). The solvent and the toluene are mixed, heated, and then charged to a distillation column... 

---