Desulphurisation of flue gases, esp. from coal-fired power stations - by scrubbing with dilute sulphuric acid contg. ferrous sulphate oxidn. catalyst

摘要

Desulphurisation involves scrubbing and catalytic oxidn. of the SO2-enriched wash liquor to H2SO4. The Fe(II) sulphate catalyst is added to the liquor in the scrubber and is removed electrolytically as Fe from a side stream of the acid, the Fe being returned to the wash liquor via dissoln. equipment. The process allows recycling of the catalyst and removal of all harmful materials present in the flue gas. Environmental pollution is avoided, since no waste liquor with a high chloride content is produced. The process can be combined with other processes to give marketable or disposable end-prods., e.g. 76% H2SO4 useful in pickling, fertiliser mfr. etc. Subsequent processes include conversion of the Cl2 formed in electrolysis to hypochlorite and use of this and the water used for washing the solids filtered from the side stream for prepn. and decarbonation of the cooling tower water; and concn. of the excess acid from electrolysis, with recovery of HCl acid contg. small amts. of HF and conversion of the NO formed to N2.