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Overall plan for COURSE50

Concept and current state of CO₂ ultimate reduction in the steelmaking process (COURSE50) aimed at sustainability in the Japanese steel industry

Since FY2008, Japanese steel manufacturers (four blast furnace steel manufacturers and one engineering company) have been promoting projects for the “Development of technologies for an environmentally harmonized steelmaking process” under COURSE50 (CO₂ Ultimate Reduction in Steelmaking process by innovative technology for cool Earth 50), a national project commissioned by the New Energy and Industrial Technology Development Organization. The goal of COURSE50 is to establish technologies which contribute to a mitigation of approximately 30 % in CO₂ emissions at integrated steel plants by 2050. Two kinds of technologies are being investigated: (a) Intensified hydrogen reduction of iron ore using coke oven gas to curb carbon input in blast furnaces, and (b) Sequestration of CO₂ in the blast furnace gas through the chemical absorption method and physical adsorption method by the effective utilization of unused waste heat in the integrated steel plants. In the case of (a), the main challenge is the conservation of global and local heat balances in the blast furnace. In the case of (b), the main task is improving the energy consumption of chemical absorption and physical adsorption by improving the agents and materials as well as the process.

執筆者/発表者	Shigeaki Tonomura, Naoki Kikuchi, Natsuo Ishiwata, Shin Tomisaki, and Yukio Tomita
公表日	2016/6/28
公表先	Journal of Sustainable Metallurgy
公表資料	2, 191–199 (2016)

Method for reducing CO₂ in blast furnace

Improvement in reduction behavior of sintered ores in a blast furnace through injecting of reformed coke oven gas

As an innovative route to mitigating CO₂ emissions in ironmaking, increasing the hydrogen reduction in a blast furnace is promising. One possible method is the shaft injection or blast tuyere injection of coke oven gas (COG) with its hydrogen concentration enhanced by steam-reforming methane and tar. Therefore, the reduction behavior of sintered ores in a blast furnace by injecting reformed COG was investigated using a softening-melting tester and counter-current reaction simulator (BIS). The shaft injection of reformed COG promoted the reduction and improved the permeability of the ore layer, particularly in the wall area of the blast furnace. An injection rate larger than 200 Nm3/t-HM was required for reformed COG for a limiting intermediate distribution ratio of injection gas lower than 20% in a large blast furnace. Unchanged shaft temperature and increased hydrogen reduction were observed during the shaft injection of hot reformed COG in the BIS test. The water-gas shift reaction below the temperature of the thermal reserve zone was insignificant even for the shaft injection of reformed COG. As for tuyere injection, direct reduction was decreased by increasing the injection rate of reformed COG from tuyere. The injection of COG with or without reforming from tuyere reduced the carbon consumption of the blast furnace by 10 kg/t-HM. The influence of the composition of COG on carbon consumption was insignificant. Direct observation of hydrogen reduction revealed a decrease in flooding molten slag in the upper coke layer during reduction, thus explaining the improved permeability of the ore layers

執筆者/発表者	Kenichi Higuchi, Shinroku Matsuzaki, Koji Saito, Seiji Nomura
公表日	2020/10/15
公表先	ISIJ International
公表資料	Vol. 60 (2020), No. 10, 2218-2227

Effect of Large Amount of Co-injected Gaseous Reducing Agent on Combustibility of Pulverized Coal by Non-Contact Measurement

Nowadays, reduction of amounts of CO₂ from ironmaking process is important from the aspect of prevention of the global warming. COURSE50 is Japanese national project which aims to reduce the amount of CO₂ emission from ironmaking process by 30% by 2050. In COURSE50, we try to reduce iron oxide with H2 to decrease amounts of carbon use, by injecting large amount of gas containing H2 and pulverized coal (PC) from tuyere. In that case, PC combustibility can be different from that in general blast furnace condition, due to high co-injected reducing gas ratio. Though a large number of researches about PC combustion around tuyere of blast furnace has been carried out, the effect of large amounts of co-injected reducing gas on PC combustibility was hardly investigated. To evaluate that, we conducted experiments with two experimental furnaces equipped with various non-contact measurement apparatus and found that;
1) The larger amounts of co-injected reducing gas were, the faster O2 and CO₂ consumption, and CO and H2 generation in the raceway.
2) The amounts of co-injected reducing gas should be optimized for higher PC combustibility.
3) Co-injected reducing gas activated PC combustion by raising PC temperature, and that resulted in acceleration of PC.
4) Trade-off relationship between rapid heating effect and O2 consumption of co-injected reducing gas could determine the optimum amounts of reducing gas.
Consequently, we elucidated how we could co-inject reducing gas with PC as reducing agents without deteriorating PC combustibility.

執筆者/発表者	Kota Moriya, Koichi Takahashi, Akinori Murao, Takeshi Sato, Kiyoshi Fukada
公表日	2020/1/27
公表先	ISIJ International
公表資料	Vol. 60 (2020) No.8 p1662

Sustainable aspect of CO₂ ultimate reduction in steelmaking process (COURSE50 project), part 1: hydrogen reduction in the blast furnace

COURSE50 (CO₂ Ultimate Reduction in Steelmaking process by innovative technology for cool Earth 50) aims to increase the proportion of hydrogen reduction in the blast furnace. This objective raises the key issue of heat balance changes in individual regions as well as in the overall blast furnace. In order to compensate for the endothermic reactions of hydrogen, a decrease in direct reduction by carbon, a huge endothermic reaction, is being executed. Among the various hydrogen sources available in the industry, coke oven gas (COG) was chosen because of its availability and stability. However, COG requires reforming for it to be injected into the shaft of the blast furnace because this zone cannot combust the hydrocarbon components of COG. COURSE50 has carried out successful COG and reformed COG injection trials at LKAB’s experimental blast furnace in Luleå, Sweden, in cooperation with LKAB and Swerea MEFOS. Carbon consumption in both the COG and reformed COG injection periods decreased compared with the base period because of the planned increase in hydrogen reduction instead of direct reduction by carbon. These results indicate the possibility of increasing the amount of hydrogen reduction in the blast furnace.

執筆者/発表者	Koki Nishioka, Yutaka Ujisawa, Shigeaki Tonomura, Natsuo Ishiwata, and Peter Sikstrom
公表日	2016/5/23
公表先	Journal of Sustainable Metallurgy
公表資料	2, 200–208 (2016)

Improvement of Coke Strength by High-Performance Binders

Effect of volumetric breakage due to DI measurement on pore structure in coke

Coke strength is an important property and generally evaluated with Drum Index (DI). It is considered that coke breakage occurs by two types of breakages during DI measurement, surface breakage and volume breakage. In this study, the cause of volume breakage was investigated by image analysis of cross-sectional image of coke before and after the DI measurement. As a result, a new image analysis method was developed. In this image analysis method, pore shape and coke-matrix connectivity were evaluated and new parameters “degree of Irregularity (I)” and “Connectivity Index (CI)” were proposed. I and CI represent pore shape and coke-matrix connectivity, respectively. By using this image analysis method, it was revealed that pore shape and coke-matrix connectivity were improved on adding HPC (High Performance Caking additive). By comparing the cross-sections before and after the DI measurement, it was found that the volume breakage occurred at the portions which have higher porosity, coarse pores, cracks and thin pore wall. Furthermore, it was clarified that the thickness of the pore wall broken by the DI measurement was < 7.6 µm thickness.

執筆者/発表者	Naoto Sakimoto, Toshimasa Takanohashi, koji Sakai, Takahiro Shishido, Takuya Yoshida, Noriyuki Okuyama
公表日	2015/4/1
公表先	ISIJ international
公表資料	Vol. 56 (2016), No. 11 pp. 1948-1955

CO₂ separation by chemical absorption

Prediction of the Basicity of Aqueous Amine Solutions and the Species Distribution in the Amine−H2O−CO₂ System Using the COSMO-RS Method

A conductor-like screening model for real solvents (COSMO-RS) was applied to the study of the amine−H2O−CO₂ system. pKa values for 25 amines including a variety of alkanolamines and some cyclic or aromatic amines were calculated by the COSMO-RS method coupled with the density functional theory (DFT). The predictions of pKa values were compared using different DFT levels for geometry optimization and also with those based on another solvation model (SM5.4/A). The DFT-COSMO calculation at the BP/TZVP level has shown a relatively good correlation with experimental values for the 25 amines (R2 ≅ 0.8) at a low computational cost. With this method, we have developed a calculation model to predict the equilibrium ratio between carbamate and bicarbonate anions in a CO₂-loaded aqueous amine solution and have confirmed the validity of the prediction model by 13C NMR spectroscopy.

執筆者/発表者	H. Yamada, S. Shimizu, H. Okabe, Y. Matsuzaki, F. A. Chowdhury, Y. Fujioka
公表日	2010/1/20
公表先	Industrial & Engineering Chemistry Research
公表資料	49, 2449-2455 (2010)

Results of RITE’s Advanced Liquid Absorbents Develop for Low Temperature CO₂ Capture

In the present paper, we investigated CO₂ capture with six amine based absorbents, including three formulated solvents. Aqueous solutions of the amines (mass fraction; 30% for single amine and >30% for blended solvents) were used to evaluate the performance for CO₂ capture. Gas scrubbing, vapor-liquid equilibrium (VLE), and reaction calorimetry experiments were conducted in the laboratory to obtain the absorption rate, the amount of CO₂ absorbed, cyclic CO₂ capacity, and heat of reaction for each absorbent. The results of these absorbents were compared with the conventional amine absorbents (MEA, AMP, DEA, and MDEA). Three high performing formulated absorbents (RN-1, RN-2, and RN-3) were developed, and these had lower heats of reaction, higher cyclic capacities, and comparable absorption rates compared with MEA. Some blended solvents were already demonstrated with real blast furnace gas at pilot test plants with capacities of 1 ton-CO₂/day and 30 ton-CO₂/day and showed promising results in terms of reducing absorbent regeneration energy.

執筆者/発表者	F. A. Chowdhury, K. Goto, H. Yamada, Y. Matsuzaki, S. Yamamoto, T. Higashii, M. Onoda
公表日	2017/7/1
公表先	Energy Procedia
公表資料	114, 1716-1720 (2017)

Catalysis of CO₂ Absorption in Aqueous Alkanolamine Solution by Boronic Compounds: A Combined Computational and Experimental Study

Theoretical and experimental investigations have been performed to obtain carbonic anhydrase (CA) mimic catalysts that are effective for CO₂ absorbents containing highly concentrated amines. One of the most serious problems associated with such absorbents is the inhibition of catalysts due to strong binding of the reaction products—bicarbonates and alkylcarbonates—as well as amine compounds at the active site of the catalysts. The active form of the CA mimic catalyst, M–OH, must be formed prior to the binding of such inhibitors. Taking into account the fact that OH– is a Lewis base that is harder than the inhibitors, we focus on hard Lewis acids, in particular, boron compounds, on the basis of the Hard and Soft Acids and Bases principle. With the aid of density functional theory (DFT) calculations, we experimentally confirm that triphenylborane and boric acid derivatives are efficient catalysts for CO₂ absorption in an aqueous solution of 30 wt % 2-(isopropylamino)ethanol. The DFT calculations predict that the intrinsic reactivity toward CO₂ is improved, while the resistance to inhibitions is reduced, as the hardness of the boron center is decreased.

執筆者/発表者	Y. Matsuzaki, S. Yamamoto, H. Yamada, F. A. Chowdhury, K. Goto
公表日	2020/6/26
公表先	Industrial & Engineering Chemistry Research
公表資料	59, 13016-13023 (2020)

CO₂ separation by physical adsorption

Reduction of electric power consumption in CO₂-PSA with Zeolite 13X adsorbent

Reduction of CO₂ from waste gases from various industries is now desired worldwide. As a technology for separating CO₂ from mixed gases, Pressure Swing Adsorption (PSA) is one of the practical processes that are widely used at present owing to the simplicity of its gas separation mechanism. In order to reduce the cost of CO₂ separation, a further reduction of the running cost of CO₂-PSA operation is required. Among all the utilities used in CO₂-PSA, electric power consumption has the greatest impact, especially in cases where the pressure swing range between gas adsorption and gas desorption is large. Electric power consumption increases significantly when the pressure loss inside the adsorber has reached a non-negligible level. Changing the adsorbent pellet size is a convenient method for reducing pressure loss, but its effect on CO₂-PSA performance was unclear. Therefore, in this work, the effects of the size of the adsorbent pellets on both the gas adsorption behavior and the electric power consumption in CO₂-PSA were evaluated experimentally. From the results of laboratory-scale CO₂-PSA experiments and gas adsorption rate measurements, it was observed that the effect of the pellet size appeared only in the early stage of the gas adsorption step and was not dominant when the cycle time was sufficiently long. Subsequently, pilot-scale CO₂-PSA experiments with the same CO₂ throughput were also conducted, and as a result, the electric power consumption of a vacuum pump was lowered by 15% in case of using d = 3.0 mm larger adsorbent pellets compared to the results with d = 1.5 mm smaller adsorbent pellets.

執筆者/発表者 Nobuyuki Shigaki, Yasuhiro Mogi, Takashi Haraoka, Ikuhiro Sumi

公表日 2018/4/11

公表先 Energies

公表資料 2018, 11, 900

執筆者/発表者	Nobuyuki Shigaki, Yasuhiro Mogi, Takashi Haraoka, Ikuhiro Sumi
公表日	2018/4/11
公表先	Energies
公表資料	2018, 11, 900

Recovery of waste heat from a trial high-performance heat exchanger

Heat recovery from low-temperature off-gas using micro-channel heat exchanger

In the COURSE50 project, a CO₂ separation and recovery system using an amine aqueous solution has been considered. In the system, the aqueous solution should be heated in a recovering process for the desorption of CO₂.The recovering temperature is less than 100 oC; thus, exhaust gases of steel plants can be utilized for heating. In this research, we first appraised the quantity of heat required in the project to recover 20 % of the CO₂ emitted from a representative steel works, designed a heat-recovering network to collect the heat from exhaust gas sources across the steel works, and found that pressured water was appropriate as the heat recovering medium. Second, we estimated the required efficiency of heat exchangers and realized that a heat exchanger with micro water vessels was appropriate because the flow rate of pressured water is much less than the gases. We designed and manufactured trial one and measured its efficiency in our laboratory using air and water. Finally, we experimentally measured the variation of its efficiency with time using real exhaust gas of a furnace of a steel plant.

執筆者/発表者 Kazuaki KOBAYASHI1*, Yuki KUWAUCHI, Yuji OGAWA

公表日 2017/10/11

公表先 EMECR 2017

執筆者/発表者	Kazuaki KOBAYASHI1*, Yuki KUWAUCHI, Yuji OGAWA
公表日	2017/10/11
公表先	EMECR 2017

Recovery of waste heat from molten slag

Effect of gas velocity distribution on heat recovery process in packed bed of plate-shaped slag

A new twin-roll continuous slag solidification process and heat recovery process from a slag packed bed was developed for utilization of the waste heat of steelmaking slag. Plate-shaped slag with the thickness about 7 mm was successfully produced in a pilot plant, and the sensible heat of the slag was recovered by blowing air into the slag chamber. However, the gas distribution inside the slag packed bed was unclear because of the unique shape of the slag plates, and this remained a concern for further scale-up designing of the slag chamber. Therefore, in order to estimate the gas distribution in the packed bed, a simple computational fluid dynamics (CFD) model which considers the wall effect around the inner wall of the chamber was developed, and this model was fitted to the results of laboratory-scale velocity distribution measurements. The results showed that the gas velocity distribution was properly estimated, and the intensity of the wall effect was similar in both cases. As the next step, the gas velocity distribution and its effect on the slag heat recovery process in a pilot-scale slag chamber were evaluated with the assistance of the CFD simulation model. The simulation results were compared with the measured data obtained in a pilot-scale test, and as the result, a similar wall effect was also observed in the pilot-scale chamber. However, the intensity of the wall effect was limited enough to prevent serious deterioration of the uniformity of the gas distribution.

執筆者/発表者 Nobuyuki Shigaki, Sumito Ozawa, Ikuhiro Sumi

公表日 2017/5/28

公表先 Energies

公表資料 2017, 10, 755

執筆者/発表者	Nobuyuki Shigaki, Sumito Ozawa, Ikuhiro Sumi
公表日	2017/5/28
公表先	Energies
公表資料	2017, 10, 755

Heat recovery process from a packed bed of hot slag plates

Reduction of CO₂ emissions from the steelmaking process is strongly required for prevention of global warming. One promising heat resource that is estimated to have great potential for energy saving is the waste heat of steelmaking slag, which has a temperature of above 1 673 K in the molten state. This molten slag can be solidified in a plate-like shape by feeding it on the surface of water-cooled rolls, and the heat of the plate-like slag can be recovered easily in spite of its low heat conductivity. When these hot slag plates are packed in a slag chamber, the heat of the slag can be recovered by heat exchange with a counter current gas flow. Because the efficiency of gas-slag heat transfer changes depending on the shape of the packed slag, it is difficult to estimate the efficiency of slag heat recovery without evaluating the accuracy of the heat transfer coefficient in the bed. In this work, the effect of the slag shape on the accuracy of the heat transfer equation was evaluated by conducting both laboratory-scale and pilot-scale slag heat recovery experiments and performing a fitting analysis by using a slag packed bed heat transfer simulation model. A comparison of the experimental results and calculation results confirmed that the heat transfer coefficient can be estimated by using Johnson-Rubesin’s equation modified by a correction factor in case the packed materials are plate-like. The effect of the correction factor on the efficiency of slag heat recovery at the industrial scale was also estimated.

執筆者/発表者	Nobuyuki Shigaki, Hiroyuki Tobo, Sumito Ozawa, Yasutaka Ta, Kazuma Hagiwara
公表日	2015/10/15
公表先	ISIJ International
公表資料	Vol.55 (2015), No.10, p2258

PAGE TOP

TECHNOLOGY

Overall plan for COURSE50

Concept and current state of CO2 ultimate reduction in the steelmaking process (COURSE50) aimed at sustainability in the Japanese steel industry

Method for reducing CO2 in blast furnace

Improvement in reduction behavior of sintered ores in a blast furnace through injecting of reformed coke oven gas

Effect of Large Amount of Co-injected Gaseous Reducing Agent on Combustibility of Pulverized Coal by Non-Contact Measurement

Sustainable aspect of CO2 ultimate reduction in steelmaking process (COURSE50 project), part 1: hydrogen reduction in the blast furnace

Improvement of Coke Strength by High-Performance Binders

Effect of volumetric breakage due to DI measurement on pore structure in coke

CO2 separation by chemical absorption

Prediction of the Basicity of Aqueous Amine Solutions and the Species Distribution in the Amine−H2O−CO2 System Using the COSMO-RS Method

Results of RITE’s Advanced Liquid Absorbents Develop for Low Temperature CO2 Capture

Catalysis of CO2 Absorption in Aqueous Alkanolamine Solution by Boronic Compounds: A Combined Computational and Experimental Study

CO2 separation by physical adsorption

Reduction of electric power consumption in CO2-PSA with Zeolite 13X adsorbent