Method for refining coke oven gas in wet desulfurizing process

• Main Author: YOO, GYE SU
• Format: Patent
• Language: English; Korean
• Published: 30.04.2004
• Edition: 7
• Subjects: PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TRANSPORTING

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. 본 발명에 따른 습식 탈유공정에서의 COG 정제방법은 COG의 불순물인 시안을 제거하는데 필요한 유황 함량을 미리 계산하고 습식 탈유공정 내의 유황 함량을 상기 계산된 양만큼 적정하게 유지함으로써 유황에 의해 맹독성의 시안화나트륨을 무해한 로단염으로 변화시키는 반응을 최적화하는 방법을 제공하는 데 그 목적이 있다. 이러한 목적을 달성하기 위해 본 발명은, 흡수탑, 재생탑 및 완충조에 의해 이루어지는 종래의 습식 탈유공정에서의 COG 정제방법에 있어서, 상기 흡수탑에서 흡수되는 시안(CN)의 양을 연속적으로 측정하고, 그 측정값으로부터 제어컴퓨터가 적정 유황 함량의 설정값을 계산하는 단계; 상기 완충조에서 생성된 다유화나트륨(NaS)을 유황 조정조로 공급하며, 그 공급된 다유화나트륨 중 상기 제어컴퓨터에서 계산된 설정값에 부합되는 양만큼을 재생탑으로 재공급하는 단계를 더 포함하는 것을 특징으로 한다.