Page 17 - Microsoft Word - Sulfo and Sulfa 1.doc

Figure 17. Continuous Tandem Type Sulfonation-Sulfation with Oleum

Neutralized
Detergent
Slurry
Alkyl Benzene Reaction
from Storage Coil

Oleum Sulfonation Sulfation Neutralization
from Cooler Cooler Cooler
Storage
Proportioning Mixing Mixing Alkali Mixing
Pump Pump Pump Pump

Fatty Alcohol Oleum
from Storage from Storage
Sulfonation Sulfation Neutralization

Air/SO Sulfonation Equipment
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Four possible sources of SO gas used for an air/SO sulfonation system are:
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3
• Sulfuric acid plant converter gas
• SO from boiling concentrated oleum
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• Liquid SO
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• Sulfur burning in equipment specifically designed to produce SO gas
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for sulfonation

Converter gas from a sulfuric acid plant contains 10–12% SO and appears to be a
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potential SO source for sulfonation. There are several problems with using a sulfuric
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acid plant as an SO source for sulfonation. Nevertheless, such an arrangement has been
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commercially installed and at first glance appears to be an attractive, low cost method of
supplying SO gas to a sulfonation plant. Physical location is a limiting factor; as the
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sulfonation plant must be installed as closely as possible to the sulfuric acid plant
converter. In addition, the sulfonation plant can run only when the sulfuric acid plant is
running.

There are three other more subtle difficulties when using a sulfuric acid plant as an SO
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source for sulfonation. First, the SO gas at approximately 18% concentration must be
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diluted to the normal range for sulfonation (typically 4–7%). An auxiliary air supply
must be installed, which adds expense and complexity. Second, because sulfuric acid
absorption towers are used for air drying, the air/SO from a sulfuric acid plant has a
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higher dew point (typically –35°C) than that required in a sulfonation plant (typically –

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