CO_2 capture from hot stove gas in steel making process

摘要

The capture of CO_2 from a hot stove gas in steel making process containing 30 vol% CO_2 by chemical absorption in a rotating packed bed (RPB) was studied. The RPB had an inner diameter of 7.6 cm, an outer diameter of 16 cm, and a height of 2 cm. Theaqueous solutions containing 30 wt% of single and mixed monoethanolamine (MEA), 2-(2-aminoethylamino)ethanol (AEEA), and piperazine (PZ) were used. The CO_2 capture efficiency was found to increase with increasing temperature in a range of 303-333 K. Itwas also found to be more dependent on gas and liquid flow rates but less dependent on rotating speed when the speed was higher than 700 rpm. The obtained results indicated that the mixed alkanolamine solutions containing PZ were more effective than thesingle alkanolamine solutions. This was attributed to the highest reaction rate of PZ with CO_2. A higher portion of PZ in the mixture was more favorable to CO_2 capture. The highest gas flow rates allowed to achieve a desired CO_2 capture efficiency andthe correspondent height of transfer unit (HTU) were determined at different aqueous solution flow rates. Because all the 30 wt% single and mixed alkanolamine solutions could result in a HTU less than 5.0 cm at a liquid flow rate of 100mL/min, chemicalabsorption in a RPB instead of a packed bed adsorber is therefore suggested to capture CO_2 from the flue gases in steel making processes.