Preface to the Special Issue on “Recent Approaches to Control of Cohesive Zone Phenomena and Improvement of Permeability in Blast Furnace”

摘要

Social and economic circumstances around steelmakingindustries have drastically changed. The Paris Agreementaims to hold the increase in the global average temperatureto well below 2°C above pre-industrial levels and pursu-ing efforts to limit the temperature increase to 1.5°C. Torealize this aim, every developed country set its nationaldetermined contributions with several ten percent of thereduction in greenhouse gas emissions by 2030. In paral-lel, the trend of fossil fuel divestment has been expanded.The steelmaking industries emit a huge amount of CO 2 andare requested to take drastic technical transformation, suchas the conversion of reducing agent and carbon recycling.Although various technical developments are in progressall over the world, the current ironmaking process mustbe ultimately improved at the same time. With such back-ground, the low-carbon operations of blast furnace havebeen pursued. Under the low-carbon operation of the blastfurnace, supplies of thermal energy and reducing gas thatare important driving forces of the process decrease, andthe volume of the coke bed that maintains the permeabilityin the furnace decreases. Additionally, the degradation ofthe ironmaking resources, such as a decrease in the particlediameter, increases in the combined water and ganguematerials, has been progressing. To realize the low-carbonoperation of the blast furnace under such circumstances, theoperation efficiency of the blast furnace must be improvedwhile avoiding operation instabilities. It is considered thatone of the key issues to realize the highly efficient and stableoperation of the blast furnace is to control cohesive zone.