Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 44.2.4 Product H 2 SO 4 treatmentTable 4.6 gives an overview of the potential treatment of the product H 2 SO 4 .TreatmentDilutionSO 2 strippingParticulateremovalDescriptionThe acid produced, generally 94 %, 96 % or 98.5 – 99.5 %, is diluted with water or steamcondensate to the usual commercial concentrations/usage concentrations (25 to 99 % H 2 SO 4 ).Dilution is carried out batchwise (“acid into water not vice versa!”) or continuously by inlinemixing.The hot acid is stripped with air in order to reduce the concentration of dissolved SO 2 to levelsbelow 30 mg/kg. The exhaust gas is returned to the contact process.After plant shutdown for maintenance, the sulphuric acid can contain particulatecontaminants, arising from insoluble iron sulphate or silicates from linings or filling materials.The removal is carried out with conventional equipment. Filtration is also carried out in filllines to road tankers or rail cars.Exhaust gascontaminantsNoneNoneNoneApplicabilityDe-nitrificationDecolourisation“Acid bleaching”Mercury removalSuperLig methodToho zinc methodEquivalent amounts of reducingchemicals are added in order toreact with NOHSO 4 (nitosylsulphuric acid) to nitrogen orUrea Absorber/tank N 2 Limited to