Page 133 - Plant design and economics for chemical engineers

108 PLANT DESIGN AND ECONOMICS FOR CHEMICAL ENGINEERS

operating personnel. What precautions in each instance should be taken to minimize
the hazard?
23. The following information has been obtained during a test for the BOD of a given
industrial waste: 15 ml of the waste sample was added to a 500-ml BOD bottle, and
the bottle was then filled with standard dilution water seeded with sewage organisms.
A second 5OO-ml BOD bottle was filled with standard dilution water. After 5 days at
2O”C, the blank and the diluted waste samples were analyzed for dissolved oxygen
content by the sodium azide modification of the Winkler method. The blank results
indicated a dissolved-oxygen content of 9.0 ppm. Results for the diluted sample
showed a dissolved-oxygen content of 4.0 ppm. On the basis of the following
assumptions, determine the BOD for the waste. The specific gravities of the liquids
are 1.0; the waste sample contains no dissolved oxygen.
24. Outline and present solutions to the materials handling, waste disposal, and safety
problems that are encountered in the nitric acid unit shown in Figs. 2-1 and 2-2.
25. Provide a design for handling the spent acid which is removed from the settler after
the sulfonation process in the sodium dodecylbenzene sulfonate process described in
Chap. 2. The final waste effluent must meet the waste-disposal standards of EPA.
26. A process for preparing acetaldehyde is by direct oxidation of ethylene. (This process
is described in Prob. 8 of Chap. 2.) Completely analyze the various factor which
should be considered in choosing a plant site for this process. With this information,
outline possible geographical locations for the plant, noting the advantages and
disadvantages of each site.
27. The trend in the fertilizer industry during the past few years has been toward larger
and larger fertilizer plants. In terms of plant location, what are the more important
factors that should be considered and which factors become even more important as
the size of the plant is increased? Are these factors of equal importance regardless
of the type of fertilizer produced? Analyze this situation for ammonia, urea, and
phosphate fertilizer process plants.
28. Make an analysis of various means of transportation available at Chicago, IL,
Houston, TX, and Denver, CO. Use this analysis to determine what form of
transportation should be recommended from these three locations for the shipment
of the following finished chemical products:

Quantity Frequency Distance of shipment
100 lb solid Once a month 100 miles
50,000 lb solid Once a month 100 miles
50,000 gal liquid Once a week 100 miles
50,000 gal liquid Once a week 500 miles
50,000 gal liquid Daily 500-mile radius

Since destination of the chemical product can greatly affect the mode of transporta-
tion recommended, consider various destinations in this analysis, e.g., coastal loca-
tion, river location, mountain location, etc. What approximate cost would have to be
added to each shipment of finished chemical products as shipping charges in the
above analysis?