Preface to the Special Issue on “Approach of Cokemaking Technology for Low CO₂ Emission and High Quality While Extending Available Resources”

Study

Since ironmaking process require an enormous amount of energy and so the cutting down on carbon dioxide emissions is a global issue, the role of ironmaking process is especially important. To reduce carbon dioxide emissions in cokemaking, a manufacturing of high-strength coke for stable low RAR (reducing agent rate) blast furnace operation and a decrease in energy consumption in cokemaking are desired. On the other hand, the price of high-quality coal remains at an elevated level in recent years and so its resource depletion will occur in the world. From the viewpoint of securement of the raw material resource for cokemaking with maintaining cost competitiveness, the development of a technique which can widely utilize low-quality but inexpensive non or slightly caking coals and convert unused carbon resources such as subbituminous and brown coals, including carbon neutral biomass into cokemaking raw materials. In this way, it should be important to promote the fundamental research on “New Cokemaking Technology” which can utilize lower-quality coal and produce higher-quality coke with lower carbon dioxide emissions.

The division of High Temperature Process, the Board of Academic Society, ISIJ has continued specific fundamental research projects since 1977. In these projects, basic thermophysical properties of caking coals and cokes, coal carbonization control for high-quality coke production, thermos-plasticity and thermal adhesiveness of coals, high-strength and high-reactivity cokes have been investigated. The fundamental knowledge obtained from these projects was applied to the development of Super Coke Oven for Productivity and Environment toward the 21st century (SCOPE21) as a national project from 1994 to 2003. The commercial operation of SCOPE21 has started in 2008.

The specific fundamental research project called “Technique Elements for New Cokemaking Process” was established in 2015, and interesting researches were conducted from March 2015 to February 2018. The academic member for this project was researchers from universities and a national institute who specialized in carbon resources, chemical engineering, and carbonization. In addition, the middle and young research workers of Japanese ironmaking and cokemaking companies participated. Achievements of this project were reported in ISIJ International, vol. 59, No. 8 (2019).

Inheriting the preceding achievements above, the next research project called “Cokemaking Technology for Low CO₂ Emission and High Quality while Extending Available Resources” was established in March 2020 and finished in February 2022. The academic member of new project was six researchers from universities and two from national institute, and research workers of ironmaking and cokemaking companies also joined. The project aims to conduct fundamental research toward cokemaking technology contributing to energy conservation and carbon dioxide reduction when using cokes in blast furnaces and during manufacturing cokes. The following related technologies were especially focused: (1) Up-grading technology of low-quality coals and biomass to produce high-strength coke. Theorization regarding up-grading technology needs to be conducted, and so optimized conditions during upgrading can be found. (2) Conversion technology of unused carbon resources such as subbituminous, brown coals, and biomass into cokemaking raw materials. Especially, the utilization of biomass resources as raw materials is strongly desired from the point of reduction of carbon dioxide emission. (3) New carbonization technology to decrease energy consumption in cokemaking. Even though the operation is based on the reduction of the carbon impact, the production of high-strength cokes is needed.

To summarize the activities of this research project, a special issue on “Approach of Cokemaking Technology for Low CO₂ Emission and High Quality while Extending Available Resources” was invited for publication. A wide range of research fields, such as pretreatment technology of raw materials, co-processing technology of varied materials, molding technology of raw coal particles or biomass, carbonization technology which can control the carbonization temperature and pressure, and other studies related to coke utilization and application, were welcome to contribute this special issue. As a result, numerous papers had been submitted to the special issue. This fact represents many researchers have a high interest and are conducting various research to solve the depletion of raw materials resources for cokemaking and carbon dioxide emission.

We sincerely hope that this special issue will contribute to a novel cokemaking process proposal in the future. Finally, on behalf of the editors of this special issue, I am grateful to all the authors and the reviewers for their significant contributions. In addition, I am grateful to the members of the technical society, Coke committee, ISIJ for their valuable advice.