Generic Methods for Coke Oven Gas Desulphurisation by Wilfried ...

200THE COKE OVEN MANAGERS’ASSOCIATIONThe process sequence of the Perox Process is similar to theStretford Process.The chemical reaction steps are similar, too. The sulphur forming isperformed by catalyst directly, however.The Perox process needs ammonia bearing coke oven gas. Ammoniais utilized as absorbent for hydrogen sulphide and the catalysthydrochinone (parabenzolchinone) is used for sulphur forming. Sidereactions with hydrogen cyanite also lead to the formation ofthiocyanate and thiosulfate.The other wet oxidative processes (Fig. 3) such as Takahax,Thylox, Fumaks and LoCat are comparable with the Stretford andPerox processes, but using other absorbents and catalysts.All of these wet oxidative processes produce a high contaminatedwaste water, which make the addition of an elaborate treatmentfacilities necessary.Now, an overview of the third group of desulphurisation processes,the neutralization processes or also called absorption and strippingprocesses is given (Fig. 3).Neutralization ProcessesThese processes are characterised by absorption and stripping(desorption) of hydrogen sulphide and conversion into elementalsulphur or sulphuric acid as in a subsequently installed plants.The simplified flow sheet of the Sulfiban Process shows a typicalabsorption/desorption process with H 2 S scrubber, H 2 S stripper andheating equipment.In the reclaimer continuous removal of heat-stable salts isperformed. The removed hydrogen sulphide leaves the process as acomponent of the sour gas and can be processed either to elementalsulphur or sulphuric acid.