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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 SUPRACID®
process is a combination of the SULFACID® process
and an upstream acid concentrator. The
combined process can be used when the incoming gas is above 100°C and the water content
is well below its saturation point. The basic principle is to
contact the gas with a stream of acid causing water to evaporate from acid thereby
concentrating the acid in the process. This
concentration is achieved in a one or two stage concentrator comprising acid sprays and
multi-venturi nozzle trays. Hot gas entering the
bottom of the concentrator is contacted by a circulating stream of 60 to 70% sulphuric
acid (acid concentrations will vary with the application).
Weaker acid (20 to 30% H2SO4) from the second stage
concentrator is fed to the first stage. The
hot gas is cooled by evaporation of water into the gas while the weaker acid is
effectively concentrated from 20-30% to 60-70%. The
gas then passes into the second stage of the concentrator which is located directly above
the first stage. In the second stage, the
gas is cooled further, again by evaporation of the water into the gas stream. Acid at a concentration of 20 to 30% sulphuric
acid is circulated to cool the gas further by evaporation of water from the acid. In the second stage, weaker acid (approximately
14% H2SO4) from the downstream SULFACID®
reactor is mixed with the circulating acid. The
overall effect is top cool the gas and concentrate acid from 14% to 20-30% sulphuric acid.
The cooled gas leaves the
concentrator and enters the SULFACID® reactor where the
sulphur dioxide is converted to sulphuric acid by wet catalysis in the presence of oxygen,
water and carbon-bearing catalyst located in the fixed bed reactor. Product acid is drawn
from the first stage of the concentrator on level control.
The acid is cooled and filtered (if required) before delivery to storage.
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Copyright© 2005,
2006, 2007, 2008 DKL
Engineering, Inc., All Rights Reserved |
