Experimental and simulation evaluation of CO2/CO separation under different component ratios in blast furnace gas on zeolites

CO2 separation under different component ratios in blast furnace gas (BFG) is of great significance for promoting the application of top gas recovery in the iron and steel industry. The CO2 separation performance in BFG under four typical cases on zeolites modified by alkaline cations were studied. The results showed that the static selectivity increased from 6 to 15 when BFG pressure decreased from 200 to 100 kPa. In both isotherms and breakthrough experiments, it is favorable to obtain high adsorption selectivity of CO2/CO under the case of low CO2 concentration and high CO concentration. It could be attributed to the relative increase in the average energy occupied by CO2. In practical VPSA simulation, the LiX zeolites exhibited excellent CO2 recovery and purity in all cases. It suppressed the adverse effects of CO on CO2 adsorption capacity during adsorption phase and released a large amount of CO2 during desorption phase due to its significant differences in potential energy of different adsorption sites. From the two aspects of optimizing O2 injection concentration and CO2 separation performance, LiX zeolites are recommended to be used in medium oxygen blast furnaces.

Automated summary

The CO2 separation performance in blast furnace gas (BFG) with different component ratios was studied using zeolites modified by alkaline cations. Lowering the BFG pressure from 200 to 100 kPa increased the static selectivity from 6 to 15. It was found that high adsorption selectivity of CO2/CO could be obtained in cases with low CO2 concentration and high CO concentration. LiX zeolites showed excellent CO2 recovery and purity in practical VPSA simulation, making them recommended for use in medium oxygen blast furnaces.