Page 10 - Microsoft Word - Sulfo and Sulfa 1.doc

The process equipment cost is an important factor to be considered in choice of a
sulfonation process. You must look at the installed cost of the system, tankage and
required safety systems. The equipment cost is almost exactly the inverse of the reagent
cost. Here, the air/SO process is highest in cost while the simple batch sulfamic process
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is lowest. Other processes are intermediate.

The final factor to consider in the choice of sulfonation processes is the cost of waste
disposal. The chlorosulfuric acid and oleum sulfonation processes produce large
by-product streams of either hydrochloric acid or sulfuric acid. These by-products must
be recovered and sold, or disposed of as a waste. Waste disposal can have a significant
impact on the profitability of these processes, as the necessary equipment can be costly
and the disposal costs can be high.

[1]
Figure 10 shows the trends in sulfonation plants in the United States . The air/SO
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process has rapidly overtaken the oleum process as the predominate choice. This is the
result of several trends. The first is the waste disposal cost for the spent sulfuric acid
from the oleum process. The second is the desire of many processors to avoid storing a
hazardous material such as oleum. The third is the move toward compact detergent
products which reduces or eliminates the sodium sulfate content of detergent products.
The oleum process adds a large quantity of sulfate to the products and for many
applications this is not acceptable. Finally, the air/SO process is capable of making a
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broad range of very high quality products.

Figure 10. Estimated U.S. Sulfonation Plants

1980 1985 1990

No. of No. of No. of
Plant Type Plants Capacity* Plants Capacity* Plants Capacity*

SO 3 44 630.0 62 855 41 1,016
Oleum 51 720.0 50 605 39 548
Chlorosulfonic
Acid 5 35.0 6 50 6 59
Sulfoxidation 1 0.45 2 1.35 1 0.45

Totals 101 1385.45 120 1,511.35 87 1,623.45

*Million kg/yr (Information supplied by E.A. Knaggs)

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