Scale-up design

It is recommended that suspended solids be removed from the feed stream to a GAC column. If this is not possible in the scale-up design, then the effect of suspended solids should be included in the pilot run. In the upflow operation, most of the suspended solids work their way up through the GAC bed without a significant increase in pressure drop. 

The Br is a measure of the extent to which viscous heating is important relative to an impressed temperature difference. This can be of some concern in the scale-up design, v usually increasing, with other properties remaining constant. A comparison of the Br for a pilot scale (0.05-m screw) and an industrial (0.15-m screw) unit yields values of ca. 0.65, and 5.73, respectively, for the Br with A = 0.5 w/m K and rj = 500 Pa.s at 60 rpm. The numbers suggest that viscous dissipation will be important and will be much more pronounced in the case of an industrial unit. 

The dynamic response used to describe fluid motion in the system is bulk velocity. Kinematic similarity exists with geom.etric similarity in turbulent agitation [32]. To duplicate a velocity in the kinematically similar system, the kno m velocity must be held constant, for example, the velocity of the tip speed of the impeller must be constant. Ultimately, the process result should be duplicated in the scaled-up design. Therefore, the geometric similarity goes a long way in achieving this for some processes, and the achievement of dynamic and/or kinematic similarity is sometimes not that essential. 

Often the scaled-up design provides equipment or speeds that are non-standard, which then require adjust-... 

Fluxes scale directly and volumes scSe proportionately with the feed volume. A safety factor will be built into the scale-up design so that process times will not be the same. 

Safety policy, management practices, 68-69 Sax s Dangerous Properties of Industrial Materials, 78 Scale-up design... 

S. Morrell, A new autogenous and semi-autogenous mill model for scale-up, design and optimisation, Miner. Eng. 17 (2004) 437-445. 

It should be noted that the extraction rate shown in Figs. 3-7 is based on the concentration change in the stripping solution, which can be converted to the extraction rate per unit membrane area commonly used in process scale-up design. With 500 mL of the stripping solution and 1.4 m2 of the membrane area in the extractor, 1 g/(L-h) is equivalent to 0.357 g/(m2-h). Thus, the extraction rate at pH 4.0 with 40 g/L of lactic acid and 30% Alamine 336 was 7.1 g/(m2-h). A higher extraction rate can be achieved with a more reactive extractant such as Adogen 283, which is a secondary amine. 

For scale-up operations, the selection of the reactor is considered to be the key element in designing SCWO systems. Environmental regulations set the requirement for the destruction efficiency, which in turn sets requirements on the temperature and residence time in the reactor (as an example, the required DRE is 99.99% for principal hazardous components and 99.9999% for polychlorinated biphenyls, PCBs). The reactor parameters for the scale-up designs can be extrapolated from the available bench-scale data. A detailed discussion on available reactor types is given below. 

Two full-scale high temperature ACR experimental facilities were built at the Marquardt Co. (18). The first series of tests examined oil penetration in a two-dimensional version of the ACR operating at typical conditions. The experience gained from this facility was used to construct a second test facility that verified the full-scale ACR gas yields and confirmed the scale-up design methods. Both tests used similar equipment and experimental techniques. 

TIP Reactions that lead to the formation of a viscous oil may be difficult to scale up. For rapid scale-up, design conditions that do not generate any viscous oil. 

Despite a continuing strong interest in ELM operations, most of the studies conducted so tar have been devoted to batch extraction operations and little attention has been devoted to continuous operation, which is necessary for successful scale-up design procedures of these processes. Some of the models developed for continuous liquid membrane operations are discussed below. 

Fig. 9.7 Scale-up design for a planar, all metal membrane system from Union Carbide Patent 3,336,730,22 August 1967 [12], Precedence for a 10 miUion cubic feet (25 tons) per day hydrogen plant using metal membranes ...

---