Key technologies for CO2 capture and recycling after combustion: CO2 enrichment in oxygen enriched combustion of converter gas

Abstract

With the progress of industrial development, global total CO2 emissions have increased exponentially. For example, although iron and steel industries have played an important role in the process of economic development, their CO2 emission intensities have reached 2.0 tCO2/t steel. Therefore, accomplishing CO2 emission reduction in iron and steel industries will have a great impact on the overall CO2 emission reduction. Devising a method for capturing CO2, with low energy consumption and high efficiency, will be of great significance to the large-scale capture of CO2 by iron and steel enterprises. In this study, numerical simulation and experimental research are used to analyze the influence of the parameters of oxygen-enriched combustion and conditions of converter gas on the concentration of CO2 in flue gas and the generation of NOx. The variation laws for the temperature field of oxygen-enriched combustion and flue gas composition of converter gas are explored. A front-stage combustion scheme suitable for CO2 capture after combustion is then defined. Herein, the CO2 content of flue gas was 74.32%, whereas the generation of NOx was 113.3 ppm, which fulfilled the NOx emission standard for new gas-fired boilers in China. The influence of the CO2 content of flue gas on the capture efficiency and energy consumption was further studied. The capture time and power consumption were reduced by 37.6% and 38.8%, respectively. The results of this study can provide a new idea and theoretical data reference for large-scale CO2 capture and utilization in iron and steel industries.