THE COST-EFFECTIVE USE OF NICKEL ALLOYS AND STAINLESS STEELS FOR CHIMNEYS (STACKS) IN AIR POLLUTION CONTROL SYSTEMS

摘要

The majority of Air Pollution Control Systems employ wet scrubbing technology for the removal andrnneutralisation of acidic products emitted on the combustion of fossil fuels and the incineration of waste materials, priorrnto discharge of the flue* gases from a chimney or stack** to the atmosphere.rnDischarge of wet gases from a scrubber at or below dewpoint results in the formation of condensates. Inrnaddition to the formation of highly corrosive sulfuric acid in the clean gas stream, hydrochloric and hydrofluoric acidsrnmay be present to a greater or lesser degree.rnHigh alloy stainless steels and nickel base alloys are increasingly specified for the linings of the clean gasrnhandling conduit, comprising ducts, gas turning devices, flues and dampers to change direction of flow or forrnisolation.rnApplication of intrinsically expensive materials in appropriate forms permits cost-effective utilisation,rnparticularly when Life Cycle Cost criteria are taken into consideration.