Design criteria for

Scale-up and performance of a 1.47-m Scheibel column have been reported (98,154,155), as have detailed description and design criteria for the Scheibel column (156) and scale-up procedures (157). The same stage efficiency can be maintained on scale-up, and total throughput can be increased by three and one-half times at the expense of higher HETS. As of this writing, Scheibel columns up to 2.75 m in diameter are in service. 

The rotating-disk contactor (RDC), developed in the Netherlands (158) in 1951, uses the shearing action of a rapidly rotating disk to interdisperse the phases (Eig. 15b). These contactors have been used widely throughout the world, particularly in the petrochemical industry for furfural [98-01-1] and SO2 extraction, propane deasphalting, sulfolane [126-33-0] extraction for separation of aromatics, and caprolactam (qv) [105-60-2] purification. Columns up to 4.27 m in diameter are in service. An extensive study (159) has provided an excellent theoretical framework for scale-up. A design manual has also been compiled (160). Detailed descriptions and design criteria for the RDC may also be found (161). 

Kuhni contacters (Eig. 15e) have gained considerable commercial application. The principal features are the use of a shrouded impeller to promote radial discharge within the compartments, and a variable hole arrangement to allow flexibility of design for different process applications. Columns up to 5 m in diameter have been constmcted (176). Description and design criteria for Kuhni extraction columns have been reported (177,178). 

Design criteria for carbon adsorption include type and concentration of contaminant, hydrauhc loading, bed depth, and contact time. Typical ranges are 1.4—6.8 L/s/m for hydrauhc loading, 1.5—9.1 m for bed depth, and 10—50 minutes for contact time (1). The adsorption capacity for a particular compound or mixed waste stream can be deterrnined as an adsorption isotherm and pilot tested. The adsorption isotherm relates the observed effluent concentration to the amount of material adsorbed per mass of carbon. 

Giaphite with its exceptional strength and thermal stabiUty at high temperatures is a prime candidate material for many aerospace and nuclear appHcations. Its properties, through process modifications, are tailorable to meet an array of design criteria for survival under extremely harsh environmental operations. 

FIG. 17-69 Design curves for electrostatic precipitators for fly ash. Collection efficiency for various levels of percent sulfur in coal versus a) specific collecting surface, and (h) bus sections per 100,000 ftVmin (4.7 mVs). °C = (°F — 32) X (Ramsdell, Design Criteria for Precipitators for Modern Central Station Power Plants, Amen c m Power Conference, Chicago, III., 1968. )... 

Design criteria for satisfactoiy biological fluidized bed treatment systems include the major parameters given in Table 25-47. 

API Publ 937, Evaluation of Design Criteria for Storage Tanks with Frangible Roof Joints, First ed., April 1996. 

The resistance of the filter medium is negligible. Determine the filter s capacity in filtrate and the velocity of the belt. To solve this problem take a look at the design criteria for a rotary drum filter - they are very similar. 

In some cases, it is possible to combine the functions of blowdown and disengaging drums in one vessel. However, PR devices discharging liquid hydrocarbons lighter than pentane should not be connected into the drum if there is a possibility that such liquids could accumulate and be released to the sewer through the seal leg. Also, the drum vent should be sized to prevent pressure buildup due to vaporization. In these applications, the design criteria for both services must be met and special attention should be paid to potential hazards and problems which may be introduced, such as ... 

Hagstrom, K., Holmberg, R., Lehtimaki, M., Niemela, R., Radio, J., and Siitonen, E. Design Criteria for Air Filtrarion in General Industrial Ventilation. Proceedings of Ventilation 97, Ottawa, Canada, 1997, p. 59-65. 

European Committee for Standardization. CENfTC 156A)PG6 Ventilation for Buildings Design Criteria for Indoor Environment. Draft, European Prestandard prENV 1752, June 1996. 

Wilson, R. P., Jr. and Attalah, S. 1975. Design Criteria for Elame Control Devices for Cargo Venting Systems. US Coast Guard Report No. CG-D-157-75 (August 1975). Available from the NTIS, Springfield, VA 22161. 

Wilson, R. P. Jr. and Flessner, M. F. 1979. Design Criteria for Flame Arresters. Paper presented at the American Institute of Chemical Engineers 84th National Meeting, February 28-March 1, 1978, Atlanta, GA. 

Wheeler, D. E., Design Criteria For Chimney Trays, Hydrocarbon Processing July, (1968) p. 119. 

The design criteria for land units may be in accordance with local building codes using equivalent static design methods. 

Boilers and air heaters can be designed to operate in the condensing mode, that is, the outlet temperature of the products entering the flue can be at or close to the dewpoint. The usual design criteria for flues which attempt to avoid condensation are no longer applicable and it is necessary to incorporate additional features. These will include ... 

Process and Mechanical Design Criteria for FCC Feed Nozzles... 

The standpipe provides the necessary head pressure required to achieve proper catalyst circulation. Standpipes are sized to operate in the fluidized region for a wide variation of catalyst flow. Maximum catalyst circulation rates are realized at higher head pressures. The higher head pressures can only be achieved when the catalyst is fluidized. Table 7-5 contains typical process and mechanical design criteria for standpipes. 

Efforts should be made to eliminate the use of expansion joints in process piping. However, if needed, the expansion joints are used to mitigate the pipe stresses caused by large thermal movements. Table 7-9 lists the recommended mechanical design criteria for expansion joints. 

Cahan, Nagy and Genshaw examine design criteria for an electrochemical measuring system to be used for potentiostatic transient investigation of fast electrode reactions. They emphasise the importance of co-design of the experimental cell and electronics. 

Catalyst Section. The design criteria for the HYGAS plant methanation section were developed in the late 1960 s (10). At that time, three commercially available nickel methanation catalysts and one ruthenium... 

M.E. Gigliotti, Design Criteria for Plastic Package-Cushioning Materials , PLASTEC Rept 4 (1961) 3)M.C. StCyr, State of the Art,... 

The volume of carbon, sand, ion-exchange resin, or other media contained in a pressure tank and used as pre-treatment process for water. Requirements for bed depth, expansion and support, etc. are governed by the design criteria for each process. 

Check the newly chosen curriculum emphasis, articulated in the vision on the curriculum in terms of design criteria, for consistency at all stages of curriculum development. 

Fig. 2.6 Transformations from a vision on chemistry education into design criteria for an entire curriculum (1), into an exemplary unit (2), into students and teacher materials (3), into the operational form in a real elassroom, into attained learning results of students (4). The arrows in the lower part of the figure represent evaluative feedbaek loops of the transformations...

Is this vision effectively and correctly transformed into design criteria for the formal representation of a curriculum (are the criteria valid, precise and complete transformation 1) ... 

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