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Before entering the drying tower, the in the off-gas treatment section cleaned sulfur dioxide-containing gases are generally diluted to achieve an certain O2/SO2-ratio. The dried gases are then compressed to the pressure required to overcome the pressure drop of the overall plant.
The feed gas is heated stepwise in a series of indirect gas-gas heat exchangers, first cooling the hot gases from the catalyst bed and then between the individual beds. The cooled sulfur trioxide-rich gases from the last bed passed into the SO3 absorber.
At low feed-gas concentrations and with the help of highly active catalysts, tail gas concentrations are attained that are equivalent to the levels associated with standard double absorption plants based on high SO2 concentrations. If required, an existing single absorption plant can be brought into conformity with stringent anti-pollution legislation either by retrofitting an intermediate absorption stage, or by the addition of a tail gas purification system e.g. Outotec's PERACIDOX system.
We have build or designed single absorption plants for:
- Capacity of 7,900 tpd
- Feed-gas concentration of 2 vol.-% SO2
- Conversion efficiency of 99 %
For further information, please contact acid(at)outotec.com
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