Agitation speed

The ethyl acetate is distilled at 70—100°C, leaving spherical particles. This graining operation requires ca 1 to 1.5 h. Grain density and size are determined by the concentration of salt in solution, the temperature and time of the dehydration, agitation speed, and the rate of distillation of the ethyl acetate. 

Vacuum diyers are usually filled to 50 to 65 percent of their total shell volume. Agitator speeds range from 3 to 8 r/min. Faster speeds yield a shght improvement in heat transfer but consume more power. 

Material Diameter X length, m Initial moisture, % dry basis Steam pressure. Pax 10 Agitator speed, r/min Batch dry weight, kg Final moisture, % dry basis Pa X 10 Time, h Evaporation, kg/(h-m")... 

Diameter, m Length, m Heating surface, m Working capacity, m l Agitator speed, r/min Drive, kW Weight, kg Purchase price (1995) ... 

From the above data, the combination of specific throughput and agitation speed which gives the optimum performance in terms of separation can be determined. At this condition the following relationships can be calculated ... 

From the above data, the condition of throughput and agitation speed which gives the optimum performance can Be determined. 

Finally, the production column agitator speed is determined by maintaining the same power per unit volume as was used on the pilot column. 

The column is run over a range of throughputs (V -t- Vj and agitation speeds at each condition the concentrations of the streams... 

Column diameter in. Amplitude, in. Plate spacing, in. Agitator speed, strokes/min Extractant Dispersed phase Minimum HETS Throughput, gal hr- ft-2 Volumetric efficiencies V/HETS,h" ... 

From these data, plots are made of volumetric efficiency and agitation speed at each throughput level from these plots the condition which gives the maximum volumetric efficiency is selected for scale-up. 

Scale-Up of Batch Mixers The prime basis of scale-up of batch mixers has been equal power per unit volume, although the most desirable practical criterion is equal blending per unit time. As size is increased, mechanical-design reqmrements may hmit the larger mixer to lower agitator speeds if so, blend times will be longer in the larger... 

Agitator speed Feed rate Size of beads... 

The seleeted seale-up rule is applied to determine the agitator speed N2 from the equation ... 

A software package (MIXER) was developed to determine the heat transfer coefficient for any type of agitator and surface using the value in Table 7-16, fluid physical properties, agitator speed, and diameter. 

The models presented correctly predict blend time and reaction product distribution. The reaction model correctly predicts the effects of scale, impeller speed, and feed location. This shows that such models can provide valuable tools for designing chemical reactors. Process problems may be avoided by using CFM early in the design stage. When designing an industrial chemical reactor it is recommended that the values of the model constants are determined on a laboratory scale. The reaction model constants can then be used to optimize the product conversion on the production scale varying agitator speed and feed position. 

The inside eonveetive heat transfer eoeffieient h is the only element of the overall heat transfer eoeffieient U that varies with the agitation speed N. If heat is removed from an agitated reaetor using an internal eoil or external jaeket, the overall heat transfer rate depends on the rotation speed of the agitator N and if the proeess side offers the major resistanee. This is expressed by... 

The particle size of the dispersed phase depends upon the viscosity of the elastomer-monomer solution. Preferably the molecular weight of the polybutadiene elastomer should be around 2 x 10 and should have reasonable branching to reduce cold flow. Furthermore, the microstructure of the elastomer provides an important contribution toward the low-temperature impact behavior of the final product. It should also be emphasized that the use of EPDM rubber [136] or acrylate rubber [137] may provide improved weatherability. It has been observed that with an increase in agitator speed the mean diameter of the dispersed phase (D) decreases, which subsequently levels out at high shear [138-141]. However, reagglomeration may occur in the case of bulk... 

The initiator usually constitutes less than 1% of the final product, and since starting the process with such a small amount of material in the reaction vessel may be difficult, it is often reacted with propylene oxide to produce a precursor compound, which may be stored until required [6]. The yield of poloxamer is essentially stoichiometric the lengths of the PO and EO blocks are determined by the amount of epoxide fed into the reactor at each stage. Upon completion of the reaction, the mixture is cooled and the alkaline catalyst neutralized. The neutral salt may then be removed or allowed to remain in the product, in which case it is present at a level of 0.5-1.0%. The catalyst may, alternatively, be removed by adsorption on acidic clays or with ion exchangers [7]. Exact maintenance of temperature, pressure, agitation speed, and other parameters are required if the products are to be reproducible, thus poloxamers from different suppliers may exhibit some difference in properties. 

Using the grid in Figure 5-33, calculated shaft hp = 19.5, and agitator speed = 90 rpm. 

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