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| Sulphuric Acid on the WebTM | Technology Manual | DKL Engineering, Inc. |
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Knowledge for
the Sulphuric Acid Industry Introduction
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The SULFACID®
process involves the adsorption of SO2 by activated carbon and the subsequent
reaction with oxygen and water to form sulphuric acid. The SULFACID®
process has been developed to remove SO2 from waste gases generated by chemical
and metallurgical processes. SO2 is recovered in the form of dilute
sulfuric acid only (i.e. < 20% H2SO4).
The process lends itself particularly well to applications where the dilute
sulfuric acid can be directly reused, as for example in titanium dioxide production
according to the sulfate process. The features of the SULFACID® process are:
The process if design to
handle weka gas containing less than 1% volume (dry basis) SO2 and minimum 7%
volume (dry basis) O2.
The Temperature must be a minimum of 30°C and the gas cannot contain more than 30
mg/Nm³ of dust. The feed gas should also have a defined relative humidity prior to
being admitted to the SULFACID® reactor. Humidification of the feed gas
can done using water, steam or weak acid. When the feed gas enters the reactor it travels up through the catalyst bed where the sulfur dioxide is converted to sulfuric acid by wet catalysis in the presence of oxygen and water. The reaction that takes place in the presence of the catalyst is SO2 + ½ O2 + n H2O ð H2SO4 (n-1) H2O + 3.02 kJ The clean,
water-saturated gas leaving the reactor is discharged to atmosphere via a stack. The
sulfuric acid formed collects in the pores and on the surface of the catalyst is
intermittently washed out by spraying water over the catalyst. Sulfuric acid in a
concentration range of 10 to 20 wt.% flows off into a collecting tank. The
conversion of sulfur dioxide to sulfuric acid on the catalyst proceeds according to the
following reaction equation: The first SULFACID®
plant was started-up in 1968 with 14 commercial-scale systems now in operation. When
testing in the pilot scale is required, a mobile pilot plant is available to verify the
suitability of the SULFACID® process directly on site and allow optimal
scale-up to commercial operation. |
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Copyright© 2005,
2006, 2007, 2008 DKL
Engineering, Inc., All Rights Reserved |
