Sulfuric Acid Plants

The production of industrial grade sulfuric acid is a multi-step process whereby sulfur or sulfur dioxide is converted into sulfuric acid. In its simplest design, sulfur is thermally oxidized to sulfur dioxide, catalyzed to sulfur trioxide, and reacted with water to form sulfuric acid.  Additional equipment, such as heat exchangers, gas cleaning equipment, and demisters are typically required to meet process and emission objectives.

There are three main sources of sulfur for acid plants: sulfur generated from the Claus process at refineries, sulfur dioxide emitted from metallurgical roasting, and recovered sulfuric acid. The key to successful sulfuric acid production is to sufficiently clean the gas to prevent fouling of the expensive catalyst.

The design of a gas cleaning system for a sulfuric acid plant depends on the nature of contaminants in the feed.  Particulate plugs the catalyst.  Heavy metals poisons the catalyst.  Moisture must also be removed to prevent sulfuric acid formation outside of the catalyst beds.  Most gas cleaning systems use a combination of wet scrubbers and wet electrostatic precipitators (WESPs) to meet the stringent requirements of the gas entering the catalyst beds.

Envitech provides gas cleanup systems for these difficult and demanding processes. Our WESPs have a proven track record of removing heavy metals and particulate in corrosive environments and we have provided over 100 direct contact condensers.

Envitech also provides mobile scrubbers for the cleanup of NOx generated from maintenance activities.

Exhaust Sources:

  • Sulfur Burning
  • Roasters


  • Acid gases: HCl, HBr, HF
  • Particulate
  • Heavy metals: Lead (Pb), Mercury (Hg), Arsenic (As)