Method for refining coke oven gas in wet desulfurizing process

摘要

PURPOSE: A method for optimizing reaction in which high toxic sodium cyanide is changed into harmless sodium thiocyanate by sulfur by pre-calculating content of sulfur required for removing cyan that is an impurity of coke oven gas and properly maintaining content of sulfur in wet desulfurizing process is provided. CONSTITUTION: The method for refining coke oven gas in wet desulfurizing process comprises first step of supplying coke oven gas and sodium hydroxide (NaOH) into an absorption column(10), producing sodium hydrogen sulfide (NaHS) and sodium cyanide (NaCN) by reacting hydrogen sulfide (H2S) and hydrogen cyanide (HCN) contained in the coke oven gas with sodium hydroxide, and leaving out the sodium hydrogen sulfide and sodium cyanide and discharging the rest of gases; second step of calculating a set value of proper sulfur content required for refining the cyanogen from the measured values using a control computer(70) after continuously measuring an amount of cyanogen (CN) absorbed from the absorption column; third step of discharging the sodium thiocyanate (NaSCN) after producing sodium hydroxide and sulfur and sodium thiocyanate (NaSCN) by transferring the sodium hydrogen sulfide and sodium cyanide remained in the absorption column to a regeneration column(20) and supplying compressed air, catalyst and Na2Sx+1 as much as an amount corresponding to the set value calculated in the control computer into the regeneration column; and fourth step of supplying the Na2Sx+1 into a sulfur balancing tank(60) and resupplying the supplied Na2Sx+1 as much as an amount corresponding to the set value calculated in the control computer into the regeneration column after transferring sulfur produced in the regeneration column into a buffer tank(30) and supplying sodium hydroxide and hydrogen sulfide into the buffer tank, thereby producing Na2Sx+1.