Comparative analysis of energy requirements of CO_2 removal from metallurgical fuel gases

摘要

The paper presents preliminary results of the analysis concerning a CO_2 removal process, applied to metallurgical fuel gases: blastfurnace gas and Corex gas. The CO_2 removal is realised by the physical absorption process with the Selexol solvent as the absorbing liquid. The analysis is focused on the energy consumption in the case of such installations, when blast-furnace gas or Corex gas are supposed to be treated. The CO_2 removal from metallurgical gases can be attractive from both technological and environmental points of view. Decreased CO_2 content in the gases and increased lower heating value (LHV) results in better conditions for its utilisation e.g. in a gas turbine-based combined heat and power (CHP) plant or direct utilisation within the process, e.g. as an auxiliary fuel or reducing gas in a blast furnace. As the composition, flow rate and LHV of the raw blast furnace and Corex gases differ strongly, the physical absorption installation has different requirements and operation parameters in the two cases. The optimisation leads to minimal energy consumption with the assumed CO_2 removal efficiency. The results indicate which technology of pig-iron production has greater potential in the field of mitigation of greenhouse gas emissions, with respect to the technological possibilities of utilisation of the treated fuel gases.