Sulfur dioxide gas is required to produce sulfuric acid. Sulfur dioxide can be obtained from burning sulfur, from roasting of sulfide ores in a smelter or decomposition of spent acid. Gas from smelters or spent acid are contaminated with heavy metal fumes and particulate, and can not be processed further without cleaning and cooling as dirty gas will produce poor quality acid, foul up filters and catalyst beds and will increase corrosion of the various equipment. The gas cleaning process includes humidification, cooling and the removal of acid mist. The conventional equipment for humidification and gas moling is fabricated from steel, lined with lead and acid-proof bricks. If fluorides are present, acid-proof brick lining is protected by carbon brick lining. The electrostatic mist precipitators are normally fabricated from lead-lined steel, In the installation of gas cleaning equipment, the materials of construction used are found to be marginal, at best installation is very labor intensive, requiring a wide variety of materials, high quality field workmanship and longer instruction schedule. Maintenance of this equipment is frequent, expensive and very time consuming. Also, lead burning in the field is a serious health hazard. Application of newer technology, innovative design, capability of field fabrication of large Fiberglass Reinforced Plastics (FRP) vessels and the new ASME RTP-1 standard allows the use of FRP vessels, which results in a most rest-effective design and reduces the construction schedule.
Keywords: sulfuric acid, gas cleaning, humidification, gas cooling, electrostatic mist precipitator, lead, acid-proof brick, carbon brick, FRP, cost, schedule, maintenance.