Mixers estimation

A liquid-gas mixture is to flow in a 3-in. Schedule 40 Kenics mixer. Estimate the pressure drop of the unit. The system conditions and physical properties are ... 

If it is desired to relate fermenter performance to oxygen uptake rate in the broth, this number can be specified along with suitable desired gas rates, and the mixer estimated, based on this performance. Again, someone must have the link between this particular mass transfer specification and the actual performance of the fermenter. 

One Ibmol of a and 2 Ibmol of b are mixed in an isothermal constant-pressure mixer. Estimate the heat added to or subtracted from the mixture from the following data ... 

In calciilating the power required for mixers, a reasonable estimate of the average density and viscosity for a two-phase system is satisfactoiy. 

Scale-Up of Continuous Mixers Although scaling up on the basis oFconstant power per unit Feed rate [kWh/lcg or (hp-h)/lb] is iisii-allv a good First estimate, several other Factors rnav have to be considered, As the equipment scale is increased, geometric similarity being... 

The Loekliart and Martinelli [32] eoiTelation is employed to estimate the two-phase pressure drop in the Kenies mixer. The pressure drop... 

A new approach for obtaining kinetic data at short reaction times utilizing a static mixer coupled to the end of an extruder was introduced. This approach yielded kinetic data for an estimated 18.6 s reaction time and is potentially capable of much smaller times. 

Applicators, mixers, loaders, and others who mix, spray, or apply pesticides to crops face potential dermal and/or inhalation exposure when handling bulk quantities of the formulated active ingredients. Although the exposure periods are short and occur only a few times annually, an estimate of this exposure can be obtained by quantifying the excreted polar urinary metabolites. Atrazine is the most studied triazine for potential human exposure purposes, and, therefore, most of the reported methods address the determination of atrazine or atrazine and its metabolites in urine. To a lesser extent, methods are also reported for the analysis of atrazine in blood plasma and serum. 

Table 1 Summary of Estimated Absorbed Doses from Mixer-Loader and Applicator Studies with Chlorpyrifos...

The third approach for estimating risk from field data is the use of Monte Carlo simulation. This has been done in this study for the greenhouse mixer/loader/applicators,5 where the model that describes the relationship between the input variables is expressed by the following equation ... 

For comparison purposes, the results of the various analyses and risk estimates for the mixers/loaders/applicators in greenhouses are summarized in Table 6. All of these analyses present the risk assessor with some information about the possible hazards to workers who are exposed to... 

In the mid-1980s, Fenske et al. (1986a,b 1993) described the use of fluorescent compounds coupled with video-imaging measurements to produce exposure estimates over virtually the entire body. The technique has been applied to pesticide mixers and applicators by Fenske and his coworkers, but has not been widely used by other investigators. 

Case-based reasoning has earlier been used for instance for equipment design. Koiranen and Hurme (1997) have used case-based reasoning for fluid mixer design and for the selection of shell-and-tube heat exchangers. They have included an estimation of design quality for the case retrieval beside technical factors. 

Additional experiments in a loop reactor where a significant mass transport limitation was observed allowed us to investigate the interplay between hydrodynamics and mass transport rates as a function of mixer geometry, the ratio of the volume hold-up of the phases and the flow rate of the catalyst phase. From further kinetic studies on the influence of substrate and catalyst concentrations on the overall reaction rate, the Hatta number was estimated to be 0.3-3, based on film theory. 

The shear stress that the material experiences for flow across a blister mixer can be estimated using Eqs. 8.12 and 8.13. For this calculation, the flow in the axial direction is ignored to simplify the mathematics, and thus only the angular flow is considered. Ignoring the axial flow causes the calculated shear rate to be lower than in the actual channel. 

Based on the U.S. EPA s SITE demonstration in 1988, the cost of treating 5000 yd of contaminated waste using a 10-yd mixer was estimated to be 152/yd. Labor and supplies were the biggest cost factors, accounting for a cumulative 74% of the total cost (D213241, p. 21). A breakdown of this economic analysis is shown in Table 1. 

Capacities of line mixers such as those of Figure 10.13 and of static mixers such as those of Figure 10.14 are stated in manufacturers catalogs. A procedure for estimating mixing efficiencies from basic correlations is illustrated by Laddha and Degaleesan (1978, p. 424). 

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