Performance of an ammonia-based CO2 capture pilot facility in iron and steel industry

Abstract

In the present paper, we report experimental results from an ammonia-based carbon dioxide (CO2) capture process operation. A pilot facility of 1000Nm3/h to remove CO2 from blast furnace gas (BFG, ∼23% of CO2) has been constructed in an iron-making workplace, resulting in the CO2 production of 10t-CO2/d. Steam generated from waste heat recovery system has been successfully supplied to the CO2 removal unit for regeneration of absorbent solution and concentration of ammonia. Technical performance shows that the facility can capture CO2 at the rate of 90% with the purity of 99% in the product CO2 stream. Results of process simulations and process operation confirmed the improvement of process economics through heat integration and pressurized absorption. Thermal energy requirement for the regeneration of absorbent solution could be lowered to 2.5GJ/t-CO2. Accordingly, the ammonia slip has been reduced to the level of ∼10ppm in both columns of absorption and regeneration. From this study we found that the technology could be a competitive option for the economic reduction of CO2 emissions in large stationary point sources such as in iron and steel industry. Conclusively, we insist that the developed technology is extremely functional if there exists waste heat at low temperature.