Coke oven gas waste water desulphurisation - by combustion with air and forming waste gas having high hydrogen sulphide to sulphur di:oxide ratio

摘要

In parent patent, waste waters, obtd. in coke over gas desulphurisation with an organic O carrier-contg. scrubbing soln., are removed by pyrolytic decomposition using the heat of the evaporating liqs. and of the waste gas formed. The inorganic components of the waste waters, conc. to 70-30% are decomposed in a reducing atmos. generated by the combustion of coke overn gas and of NH3 vapours formed in coke oven gas treatment in absence of air. S formed is sepd. Waste gas and vapours formed in waste water concn. are added to coke oven gas before pre-cooling. In this addn., waste water decompsn. takes place in a combustion chamber at 100-1100 (1050) degrees C. Air quantity added is such that waste gas formed in combustion chamber exhibits mol. ratio H2S:SO2>2:1 (2.1:1 to 2.6:1). Waste gas formed is free from N oxides. Air supply control to combustion chamber achieves optimum H2S:SO2 ratio for S deposition, according to equation 4 H2S + 2SO2 right arrow 4 H2O + 3 S2.