Some Additional Considerations about Chemical Processes

9 SOME ADDITIONAL CONSIDERATIONS ABOUT CHEMICAL PROCESSES 

The methods we present in this chapter and the rest of the text are applied universally in the chemical process industry. There are several features of industrial processes that tend not to show up in textbooks, however. You will And out about them as soon as you go to work as a chemical engineer, but it could be helpful to know about them in advance. 

Since our purpose in this text is to help you to develop skills in certain basic methods of chemical process analysis, we have intentionally omitted most of the complicating factors that can make industrial processes so difficult to manage. Once you have mastered the basics, you can start learning how to adjust for the complications. 

Material Balances in Process Design and Process Operation 

Methyl ethyl ketone (MEK) is to be recovered from a gas mixture containing 20.0 mole% MEK and 80.0 mole% at 85 C and 3.5 atm. In a proposed process design, a stream of this mixture is fed to a condenser at a rate of 500 Us and is cooled at constant pressure, causing most of the MEK to condense. 

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The nominal chemical costs (in 1994 dollars) for SuIFerox process units, based on typical iron and chelant losses, are currently projected at about 235 to 300 per long ton of sulfur (Hammond and Pirtle, 1994). Actual chemical costs experienced in some plants may be considerably higher than this because of unanticipated mechanical losses such as a high frequency of spills, above average leakage due to poor equipment maintenance, or losses due to improper sampling procedures. Additional data on chemical losses for refineiy gas treating applications are provided by Day and Allen (1992). 

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