Research progress of CO removal in flue gas of typical steel production process

CO,one of the six standard air pollutants,is toxic to human body and the environment. The steel industry releases large amounts of industrial tail gas containing CO into the atmosphere every year. Under the background of "carbon peaking" and "carbon neutral",the whole steel industry is facing huge CO emission reduction pressure. The present situation of CO emission from flue gas in typical steel production process was summarized. Continuous emissions included coke oven flue gas,sintering flue gas and rotary kiln flue gas,etc. The CO concentration in these flue gases was low and the flue gas emissions were large. For CO reduction in flue gas,the research works on source control,process reduction and terminal treatment technologies were summarized. Source control refers to replacing fossil energy with environmentally friendly hydrogen and electrical energy. Process reduction focuses on improving fossil fuel combustion conditions to reduce CO emissions. Terminal treatment involves physically/chemically separating CO from the flue gas or oxidizing it to CO₂. Among the terminal treatment technologies,catalytic oxidation technology has low investment cost,no operational energy consumption and secondary pollution,and significant emission reduction effect. In addition,it can be combined with flue gas desulfurization and denitrification technology and has the possibility of industrial practice,but the current catalysts need to be optimized in terms of anti-poisoning and preparation cost. Finally,according to the CO emission reduction of sintering flue gas is an urgent problem to be solved,the feasible technical routes and challenges for CO emission reduction of sintering flue gas were analyzed. It is suggested that low input and high efficiency CO emission reduction can be achieved by coupling flue gas cycle,medium spraying,fuel improvement and catalytic oxidation technology.