Improvement in Blast Furnace Reaction Efficiency through the Use of Highly Reactive Calcium Rich Coke

Abstract

A method to produce coke in 'lump' form with high strength and reactivity through the addition of a catalyst was investigated in order to improve blast furnace reaction efficiency. The addition of Ca compounds to coal before carbonization was found to considerably increase the reactivity of the coke at a low temperature range in the thermal reserve zone of a blast furnace. Furthermore it was proved that strong, highly reactive 'lump' form coke could be produced by adding a Ca-rich non-caking coal and adjusting the coal blend composition. Based on this fundamental study, the Ca-rich coke was successfully produced in coke ovens on a commercial scale, both at Kimitsu and Muroran works. The use of the Ca-rich coke in the Muroran No. 2 blast furnace was found to cause a decrease in the reducing agent rate by 10 kg/t-p. This technology, producing coke of high reactivity and strength through catalyst addition, is promising as a means of improving the reaction efficiency of a blast furnace.

Ironmaking Technology for the Last 100 Years: Deployment to Advanced Technologies from Introduction of Technological Know-how, and Evolution to Next-generation Process

“…187) Validation of the blast furnace models was carried out, including issues such as measurement of hot metal residence time by a radioactive element tracer, gas flow inside the furnace, research on evaluation of the high temperature properties of sinter and lump ores, research on reduction, and the reaction behavior of sinter and coke mixtures under simulated blast furnace conditions. 113,115,185) Thanks to rapid progress in computer performance, these models are now used by engineers as on-site blast furnace simulators which enable calculation on a notebook computer.…”

“…These included SCOPE21 SCOPE21 is a technology featuring strengthened coal preprocessing and high speed carbonization, and was adopted in new coke ovens at Nippon Steel Oita Works in 2008 and Nippon Steel Nagoya Works in 2013. As technologies for reduced CO2 emissions and realizing low RAR operation, technologies for thermal reserve zone temperature control and chemical equilibrium control were developed 113,115) (see section 5.1), and at JFE East Japan Works (Keihin), injection of natural gas was adopted in the blast furnace and sintering process. 52,116) A two-stage reduction system 117) combining partially-reduced iron ore manufacturing in natural gas producing countries and use of the product ore in Japanese blast furnaces was proposed as a globally-oriented CO2 reduction technology that also encompasses use of inferior quality resources.…”

“…2 blast furnaces, and a RAR reduction of about 10 kg/thm was achieved at Nippon Steel Muroran No. 2 blast furnace (inner volume: 2 902 m 3 ) by using high Ca coke 115) whose reactivity was raised by catalysis of CaO in ash. A 5 year research project with the aims of halving blast furnace energy consumption and minimizing the environmental load of the blast furnace was carried out, beginning in 1999, as a Special Coordination Funds for Promoting Science and Technology general research project.…”

Enhancement of Low-temperature Gasification and Reduction by Using Iron-coke in Laboratory Scale Tests

“…[3][4][5][6][7] Furthermore plant trials proved that Ca-rich coke containing Ca as a catalyst could decrease reducing agent rate of blast furnace. 8) Usage of low grade iron ores as raw materials of such agglomerates is attractive to meet a lack of high grade iron ore resources. Therefore the Iron-coke containing Fe as a catalyst made from the mixture of coal and fine ores have been investigated with intensity as well.…”

Fate of Nitrogen and Sulfur during Reduction Process of Carbon-containing Pellet Prepared by Vapor Deposition of Gaseous-Tar and the Influences of the Hetero Elements on the Reduction Behavior and Crushing Strength

“…So far, reducing the thermal reserve zone temperature is expected to reduce CO 2 emissions and/or energy consumption from blast furnaces. [1][2][3] Therefore, the technical development of ironmaking materials that are rapidly reducible is very important to solve these problems. However, iron materials with a low reduction disintegration index (RDI) are required for use in blast furnace because the reduction disintegration occurs in the upper region of the blast furnace by the reduction of hematite to magnetite in lump ore/sinters with a volumetric expansion, which causes a loss of permeability in the blast furnace.…”