Transferring Equipment

Due to the nature of batch operations, transferring and charging of process materials is a common activity. This can entail gas, liquids, and/or solids handling via open equipment. This may include pumping of liquids from drums or dumping of solids from other containers into an open vessel, shoveling material into a dryer, or making temporary connections such as at hose stations. 

Primary concerns include the of loss of containment and the potential for exposure of operating personnel to hazardous materials the potential for other hazards such as fires or explosions and the ergonomic issues inherent in manipulating large, heavy containers. The first two concerns are of particular significance in batch operations, since operating personnel are often more frequently and more intimately exposed to the batch processes than is typically the case with continuous processes. 

A number of design alternatives should be considered when milling materials that are combustible or are temperature sensitive, such as 

Other ignition sources should be identified and excluded through consideration of 

Milling of impact-sensitive materials should generally be avoided. 

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Even if the reactor temperature is controlled within acceptable limits, the reactor effluent may need to be cooled rapidly, or quenched, to stop the reaction quickly to prevent excessive byproduct formation. This quench can be accomplished by indirect heat transfer using conventional heat transfer equipment or by direct heat transfer by mixing with another fluid. A commonly encountered situation is... 

Use heat transfer equipment which requires a low inventory, such as plate heat exchangers. 

Fig. 17. Effect of axial dispersion in both phases on solute distribution through countercurrent mass transfer equipment. A, piston or plug flow B, axial...

George W. Gassman, Paul J. Schajhuch, Thomas J. McAvoy, Dale E. Seborg Process Economics F. A. Holland, J. K Wilkinson Transport and Storage of Fluids Meherwan P. Boyce Heat-Transfer Equipment Richard L. Shilling, Kenneth J. Bell,... 

Kenneth J. Bell, Ph.D., P.E., Regents Professor Emeritus, School of Chemical Engineering, Oklalioma State University Member, American Institute of Chemical Engineers (Section 11, Heat-Transfer Equipment)... 

Overall Coefficient of Heat Transfer In testing commercial heat-transfer equipment, it is not convenient to measure tube temperatures (t,3 or t4 in Fig. 5-6), and hence the overall performance is expressed as an overall coefficient of heat transfer U based on a convenient area dA, which may be dAi, oi an average of dAi and dA whence, by definition,... 

According to this analysis one can see that for gas-absorption problems, which often exhibit unidirectional diffusion, the most appropriate driving-force expression is of the form y — y tyBM,. ud the most appropriate mass-transfer coefficient is therefore kc- This concept is to he found in all the key equations for the design of mass-transfer equipment. 

Because heat-transfer equipment for solids is generally an adaptation of a primarily material-handhng device, the area of heat transfer is often small in relation to the overall size of the equipment. Also pecuhar to sohds heat transfer is that the At varies for the different heat-transfer mechanisms. With a knowledge of these mechanisms, the At term generally is readily estimated from temperature hmita-tions imposed by the burden characteristics and/or the construc tion. 

Conauctive Heat Transfer Heat-transfer equipment in which heat is transferred by conduction is so constructed that the solids load (burden) is separated from the heating medium by a wall. 

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