TREATMENT OF WASHING WASTE WATER FROM DESULFURIZATION EQUIPMENT OF COKE OVEN GAS

摘要

PURPOSE:To prevent the diffusion of H2S to the atmosphere, the increase of excessive sludge, the damage of a combustion furnace due to Na in washing waste water and the closure of the water pipe part of a waste heat boiler by adding sulfuric acid to the NaOH washing waste water of a desulfurization tower to recover generated H2S and free S and subjecting the residual waste water to activated sludge treatment. CONSTITUTION:Sulfuric acid 3 is added to washing waste water due to NaOH to adjust the pH of said waste water to 7 or less to liberate H2S 5 and solid sulfur. Generated H2S 5 is mixed with coke oven gas 15 to be guided to desulfurization equipment 17. The absorbing solution (desulfurization solution) 18 having H2S absorbed therein is supplied to sulfuric acid equipment 22 through a concn. tower 20 to be recovered as 98% sulfuric acid 23. The washing waste water containing free sulfur 7 is dehydrated using dehydration and washing equipment 9 and free sulfur is washed by washing water 10 and dehydrated to become sulfur sludge 11 sufficiently lowered in the concn. of Na. This sludge is mixed with the desulfurization solution 18 through a tank 21 and the resulting mixture is supplied to the sulfuric acid equipment 22 to be recovered as 98% sulfuric acid. The liquid 8 obtained by the removal of free sulfur 7 and the washing waste water 12 of sulfur are treated in activated sludge equipment.