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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 advancement in materials has created several options for the materials of construction for a Drying Tower. The traditional material of construction for the tower shell is carbon steel which has been lined with a corrosion resistant lining. Alternatives to the traditional material of construction is an all metal tower but this option cannot be used for all cases. All metal towers are sensitive to excursions from the normal operating acid concentrations and temperatures. Localized hot spots, non-wetted areas and weak acid formation have all resulted in tower failures. The gas inlet area is subject to weak acid formation due to the lack of acid flow and the wet gas entering the tower. Special attention must also be paid to the area under the packing support to ensure that acid flows evenly across the surface of the metal to avoid dry areas. The high silicon stainless steels (SX, SARAMET, ZeCor) are most sensitive to weak acid formation and the resulting higher corrosion rates. Alloy C-22 is more forgiving if the weak acid were to form inside the tower. All metal towers are generally not recommended for metallurgical or acid regeneration plants.
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