Knowledge for the Sulphuric Acid Industry
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DKL Engineering, Inc.
Technology - REGESOX™
February 15, 2003
The REGESOX™ process if used primarily for the treatment of gases containing low concentrations of CS2 / H2S. These gases are typical of the viscose fibre production process.
Sulphuric acid in the concentration range of 40 to 60 wt%H2SO4 is produced as a by-product.
The REGESOX™ is a regenerative heat exchange
process consisting of two reactors loaded with CS2 / H2S
oxidation catalyst, SO2 conversion catalyst and inert heat exchange
material. Cold wet feed gas is heated by the treated gases leaving the
second reactor. The preheated gases enters the first reactor and is heated
to the required reaction temperature by the inert heat exchange material.
The gases then pass through the CS2 / H2S oxidation
catalyst followed by the SO2 conversion catalyst. The oxidation
reactions are exothermic and the temperature of the gas increases. The hot
gases pass from the first reactor into the second reactor where the hot gases
are cooled while heating the catalyst and reactor material. The remaining
heat in the gas is used to preheat the incoming cold gas.
After 5-10 minutes, the flow is reversed. The second reactor has sufficient heat stored in the inert heat exchange material to heat the cold incoming gases to the required reaction temperature. The process of switching the first and second reactors is repeated. The sulphuric acid that is formed will condense on the heat exchange material.
The acid is collected at a temperature of approximately 60°C and a concentration of approximately 50 wt% and may be recycled directly to the spinning plant acid system of the viscose fibre plant due to the high purity of the acid.
A fuel fired heater between both reactors compensates for any heat losses and is used mainly during start-up. The system can thus be operated with nearly zero fuel consumption.