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Theoretical Foundation of Carbonation Pellet Process for Ferrous Sludge Recycling 被引量:1
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作者 HU Chang-qing HAN Tao +1 位作者 ZHANG Yu-zhu ZHANG Zhi-xia 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2011年第12期27-31,共5页
For the recycling of ferrous sludge from steel industry,the carbonation pellet process should be considered as a "green" process,since no impurities are added as well as CO2 can be sequestrated and consumed.Through ... For the recycling of ferrous sludge from steel industry,the carbonation pellet process should be considered as a "green" process,since no impurities are added as well as CO2 can be sequestrated and consumed.Through the thermodynamic calculation,the carbonation reaction can occur spontaneously and is an exothermic reaction.Based on the kinetic analysis through unreacted core model,the interfacial chemical reaction was the rate controlling step in the initial fast stage of carbonation,and the CO2 diffusion through the CaCO3 product layer was the rate controlling step in the following extremely slow stage.For the carbonation bonded mechanism,the pellet strength was gained by the formation and growing of CaCO3 product layer.Since the interfacial chemical reaction was the critical stage of the entire carbonation process,the emphasizes should be focused on the improvement of sorbent activity and the optimization of process parameters,such as pore structure,pore surface area,and total pressure,CO2 partial pressure,reaction temperature,etc to accelerate the reaction rate and to improve the quality of carbonation pellets. 展开更多
关键词 CO2 sequestration ferrous sludge carbonation pellet THERMODYNAMICS kinetics unreacted core model
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Effect of Na_2CO_3 on reduction and melting separation of ludwigite/coal composite pellet and property of boron-rich slag 被引量:2
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作者 王广 薛庆国 王静松 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第1期282-293,共12页
The effects of Na_2CO_3 on the reduction and melting separation behavior of ludwigite/coal composite pellet, the desulfurization ratio and the property of the separated boron-rich slag were investigated at laboratory ... The effects of Na_2CO_3 on the reduction and melting separation behavior of ludwigite/coal composite pellet, the desulfurization ratio and the property of the separated boron-rich slag were investigated at laboratory scale in the present work. Na_2CO_3 could improve the reduction rate of the composite pellet to some extent. The melting separation of the composite pellet became increasingly difficult with the increase of Na_2CO_3 in the pellet due to the sharply increasing of the melting point of slag. The sulfur content of the iron nugget gradually decreased from 0.27% to 0.084%(mass fraction) with the Na_2CO_3 content in the pellet increasing from 0 to 6%. The efficiency of extraction of boron(EEB) of the slow cooled boron-rich slag decreased from 86.46% to 59.52% synchronously. Na_2CO_3 had obviously negative effect on melting separation of the composite pellet and boron extraction of the boron-rich slag. 展开更多
关键词 LUDWIGITE carbon composite pellet reduction and melting separation DESULFURIZATION boron-rich slag boron extraction
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Preparation of CaO-containing carbon pellets from coking coal and calcium oxide:Effects of temperature,pore distribution and carbon structure on compressive strength in pyrolysis furnace 被引量:2
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作者 Xiao-min You Xue-feng She +2 位作者 Jing-song Wang Qing-guo Xue Ze-yi Jiang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2021年第7期1153-1163,共11页
CaO-containing carbon pellets(CCCP)were successfully prepared from well-mixed coking coal(CC)and calcium oxide(CaO)and roasted at different pyrolysis temperatures.The effects of temperature,pore distribution,and carbo... CaO-containing carbon pellets(CCCP)were successfully prepared from well-mixed coking coal(CC)and calcium oxide(CaO)and roasted at different pyrolysis temperatures.The effects of temperature,pore distribution,and carbon structure on the compressive strength of CCCP was investigated in a pyrolysis furnace(350-750℃).The results showed that as the roasting temperature increased,the compressive strength also increased and furthermore,structural defects and imperfections in the carbon crystallites were gradually eliminated to form more organized char structures,thus forming high-ordered CC.Notably,the CCCP preheated at 750℃exhibited the highest compressive strength.A positive relationship between the compressive strength and pore-size homogeneity was established.A linear relationship between the com-pressive strength of the CCCP and the average stack height of CC was observed.Additionally,a four-stage caking mechanism was developed. 展开更多
关键词 calcium oxide-containing carbon pellets calcium carbide coking coal compressive strength pyrolysis furnace
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Effect of CaO and CaCO3 on Reduction Rate of Iron Ore Pellets Containing Carbon 被引量:4
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作者 YANG Xue-min XIE Yu-sheng +3 位作者 WANG Da-guang HUANG Dian-bing KONG Ling-tan YANG Tian-jun 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2000年第2期1-5,共5页
The effect of metallurgical fluxes CaO and CaCO3 on the reduction rate of iron ore pellets containing carbon in nitrogen atmosphere has been studied by a weight-loss thermal balance. The experimental results showed th... The effect of metallurgical fluxes CaO and CaCO3 on the reduction rate of iron ore pellets containing carbon in nitrogen atmosphere has been studied by a weight-loss thermal balance. The experimental results showed that adding CaO or CaCO3 can promote reduction reaction as the added CaO or CaCO3 probably decrease the apparent activation energy of iron ore concentrate-carbon-CaO or CaCO3 reaction, and the reduction rate constant changes with mass percent of CaO and CaCO3. The kinetic analysis also showed that the rate-controlling step of the reaction is inner gas diffusion. 展开更多
关键词 iron ore pellet containing carbon reduction rate CAO CACO3
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Estimate of the Deposition Profile of Carbon Pellets Using a High-Speed VUV Imaging System in the LHD 被引量:1
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作者 明廷凤 Satoshi OHDACHI +1 位作者 Yasuhiro SUZUKI LHD Experiment Group 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第12期1178-1183,共6页
The deposition profile of the impurity pellet is measured by a two-dimensional fast- framing vacuum ultraviolet (VUV) camera system in the large helical device (LHD). The fast framing camera selectively measures t... The deposition profile of the impurity pellet is measured by a two-dimensional fast- framing vacuum ultraviolet (VUV) camera system in the large helical device (LHD). The fast framing camera selectively measures the emission from the hydrogen-like ions of carbon (C VI) with a frame rate of several kHz. From the emission profile of the hydrogen-like carbon ions, which are in the process of ionization, the initial deposition profile of the carbon is estimated using a simple one-dimensional transport model. 展开更多
关键词 VUV impurity transport carbon pellet injection LHD
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Improvement of Plasma Performance Using Carbon Pellet Injection in Large Helical Device
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作者 Shigeru MORITA Motoshi GOTO +17 位作者 Kenichi NAGAOKA Chunfeng DONG Hangyu ZHOU Zhengying CUI Yunbo DONC Xiang GAO TKatsumi IDA Katsunori IKED Osamu KANEKO Shiyao LIN Haruhisa NAKANO Masaki OSAKABE Ryuichi SAKAMOTO Yasuhiko TAKEIRI Ang TI Katsuyoshi TSUMORI Mikiro YOSHINUMA LHD experiment group 《Plasma Science and Technology》 SCIE EI CAS CSCD 2011年第3期290-296,共7页
A cylindrical carbon pellet with a size of 1.2L x 1.2φ mm to 1.8L x 1.8φ mm and a velocity of 100 m/s to 300 m/s was injected into large helical device (LHD) for an efficient fueling based on its deeper deposition... A cylindrical carbon pellet with a size of 1.2L x 1.2φ mm to 1.8L x 1.8φ mm and a velocity of 100 m/s to 300 m/s was injected into large helical device (LHD) for an efficient fueling based on its deeper deposition instead of hydrogen gas puffing and ice pellet injection. Electron density increment of Ane = 10^14 cm^-3 is successfully obtained by single carbon pellet injection without plasma collapse. Typical density and temperature of the ablation plasma of the carbon pellet, e.g., 6.5× 10^16 cm^-3 and 2.5 eV for CII, are examined respectively by spectroscopic method. A confinement improvement up to 50% compared to ISS-95 stellarator scaling is clearly observed in a relatively low-density regime of ne = 2 × 10^13 cm^-3 to 4×10^13 cm^-3, and high ion temperature Ti(0) of about 6 keV is also observed with an internal transport barrier at ne = 1.2 × 10^13 cm^-3. In particular, the improvement in the ion temperature largely exceeds that observed in hydrogen gas-puffed discharges, which typically ranges below 3 keV. 展开更多
关键词 carbon pellet injection confinement improvement high ion temperature
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Influence of furnace temperature and non-uniform heat flux density on direct reduction process of newly designed carbon containing pellet
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作者 LI Nan WANG Feng PAN Liang-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第1期296-312,共17页
In this study,innovative ellipsoid pellet with craters on its surface was designed,and the direct reduction process was compared with ellipsoid(without craters)and sphere pellets.In addition,furnace temperature and un... In this study,innovative ellipsoid pellet with craters on its surface was designed,and the direct reduction process was compared with ellipsoid(without craters)and sphere pellets.In addition,furnace temperature and uneven heat flux density effects on the pellet direct reduction process were also studied.The results show that ellipsoid pellet is better than that of spherical pellet on metallization ratio.However,under the condition of non-uniform heat flow,the ellipsoid pellet final metallization rate and zinc removal rate were lower.Although the heat transfer effect of ellipsoid pellet with craters was not improved significantly,the metallization rate and zinc removal rate were found improved,which will have a cumulative effect on the pellets direct reduction process in rotary hearth furnace.Under varying furnace temperature conditions,the pellet temperature was higher than that of the constant furnace temperature.After 1200 s,pellet Fe concentration increased to 123.6%,metallization rate and zinc removal rate increased to 113.7%and 102.2%,respectively.These results can provide references for the carbon-containing pellet design used in rotary hearth furnace. 展开更多
关键词 rotary hearth furnaces carbon containing pellets direct reduction process heat and mass transfer mathematical model
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REDUCTION BEHAVIOR OF IRON ORE PELLETS CONTAININGCARBON UNDER NON-ISOTHERMAL CONDITION
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作者 X.M.Yang Y.S.Xie +3 位作者 D.G.Wang D.B.Huang T.J.Yang L.T.Kong 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2000年第5期1059-1067,共9页
The reduction behavior of iron ore pellets containing carbon under non-isothermal condition in the temperature range from 573 to 1373 K was investigated in a laboratory scale setup. The test results show that carbon c... The reduction behavior of iron ore pellets containing carbon under non-isothermal condition in the temperature range from 573 to 1373 K was investigated in a laboratory scale setup. The test results show that carbon content has no obvious effect on reduction degree of composite pellets (C/O mole ratio=1.0) by CO in the temperature range from 573 to 1373 K under linear temperature-rising program; reduction degree of iron ore pellets containing carbon is large in 90%CO-10%CO2 mixture than that of in 100%CO atmosphere or in 80%CO-20%CO2 mixture; the s type temperature-rising program has a better effect than that of linear one in increasing the reduction degree; and reduction degree of slower linear temperature-rising program is greater than that of faster one, but the final reduction degrees, i.e., those at the highest temperature are about the same for various CO partial pressures or temperature-rising programs. The kinetic analysis also shows that the reduction of iron ore-carbon composite pellets by CO or CO-CO2 mixture under non-isothermal condition should be controlled by surface reaction, and the apparent reduction activation energy changes with the reduction progress under various test conditions. 展开更多
关键词 iron ore pellet containing carbon reduction behavior KINETICS activation energy NON-ISOTHERMAL
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Mobile power generation system based on biomass gasifcation 被引量:4
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作者 Lu Ding Mingming Yang +5 位作者 Kai Dong Dai‑Viet N.Vo Douglas Hungwe Jiahan Ye Alexander Ryzhkov Kunio Yoshikawa 《International Journal of Coal Science & Technology》 EI CAS CSCD 2022年第3期171-184,共14页
Disaster-hit and/or un-electrifed remote areas usually have electricity accessibility issues and an abundance of plant-derived debris and wood from destroyed wooden structures;this can be potentially addressed by empl... Disaster-hit and/or un-electrifed remote areas usually have electricity accessibility issues and an abundance of plant-derived debris and wood from destroyed wooden structures;this can be potentially addressed by employing a decentralized ultrasmall biomass-fed gasifcation power generating system.This paper presents an assessment of the technical viability of an ultra-small gasifcation system that utilizes densifed carbonized wood pellets/briquettes.The setup was run continuously for 100 h.A variety of biomass was densifed and carbonized by harnessing fugitive heat sources before charging into the reactor.Carbonized briquettes and furnished blends exhibited inferior gasifcation performance compared to the carbonized pellets.In the absence of tar blockage problems,steady-state conditions were achieved when pre-treated feedstock was used.Under steady-state conditions for carbonized pellets gasifcation operated at an equivalence ratio of 0.32,cold gas efciency and carbon conversion achieved 49.2%and 70.5%,respectively.Overall efciency and maximum power output of 20.3%and 21 kW were realised,respectively.It was found that the system could keep stable while the low heating valve of syngas was over 4 MJ/m^(3)on condition that avoiding tar blocking issues.The results indicate that the proposed compact ultra-small power generation system is a technically feasible approach to remedy power shortage challenge.In addition,process simulation considering carbonized wood gasifcation combined power generation was formulated to produce syngas and electricity.Woody pellets with the fow rate of 20 kg/h could generate a 15.18 kW power at the air fow rate of 40 Nm^(3)/h,which is in a good agreement with 15 kW in the 100 h operation.It is indicated that the gasifcation combined power generation cycle simulated by Aspen simulator could achieve reliable data to assist the complicated experiment operation. 展开更多
关键词 Small-scale power generation Densifcation Carbonized pellet Carbonized briquette Gasifcation
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Microstructure Variation of Pellets Containing Ferrous Dust during Carbonation Consolidation 被引量:2
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作者 Yan SHI Shi-meng LIU +1 位作者 Chang-qing HU Yu-zhu ZHANG 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2015年第2期128-134,共7页
The carbonation and microstructure characteristics of pellets containing ferrous dusts were investigated during carbonation consolidation at differem reaction temperatures and CO2 partial pressures. The results indica... The carbonation and microstructure characteristics of pellets containing ferrous dusts were investigated during carbonation consolidation at differem reaction temperatures and CO2 partial pressures. The results indicated that green pellets had loose and network supporting structure with initial strength, and large cracks and pores existed in the pellets. The carbonation reaction was controlled by interracial chemical reaction at the initial fast stage, which limited diffusion and thus caused the reaction rate to decrease. With increasing reaction temperature and CO2 partial pressure, the conversion rates of CaO and the number of microcrystalline CaCO3 particles increased, and the volume expansion of CaCO3 led to a decrease in the open porosity, average pore size and specific surface area of the pellets. Micro pores were occluded, and the number of smaller pores (diameter less than 50 nm) increased, thereby resulting in the more compact and uniform structure of carbonated pellets. Simuhaneously, the dense structure prevented CO2 diffusion into the product layer, affecting the increase in carbonation conversion rate. 展开更多
关键词 ferrous dust MICROSTRUCTURE CaO conversion rate carbonated pellet green pellet
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Reduction Kinetics of Vanadium Titano-Magnetite Carbon Composite Pellets Adding Catalysts Under High Temperature 被引量:8
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作者 ZHANG Jian-liang XING Xiang-dong +3 位作者 CAO Ming-ming JIAO Ke-xin WANG Chun-long REN Shan 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2013年第2期1-7,共7页
Experiments were carried out by adding CaF2 and NaF as catalysts in an Ar atmosphere to study the isothermal reduction kinetics of vanadium titano-magnetite carbon composite pellets under high temperature in the range... Experiments were carried out by adding CaF2 and NaF as catalysts in an Ar atmosphere to study the isothermal reduction kinetics of vanadium titano-magnetite carbon composite pellets under high temperature in the range from 1 473 to 1 673 K. The scanning electron microscope (SEM) was used to characterize the microstructure of product. By analyzing reduction mechanism, it was found that the rate controlling step was gas diffusion, and the activation energy was 178.39 kJ/mol without adding any catalysts. Adding CaF2 or NaF of 3% to vanadium titano-magnetite carbon composite pellets can decrease the apparent activation energy of reduction, and the decrease extent was 14.95 and 15.79 kJ/mol, respectively. In addition, temperature was an important factor influencing on reaction rate. 展开更多
关键词 carbon composite pellet reduction kinetic CATALYST vanadium titano-magnetite
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Reduction Characteristics and Kinetics of Bayanobo Complex Iron Ore Carbon Bearing Pellets 被引量:8
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作者 DING Yin-gui WANG Jing-song +2 位作者 SHE Xue-feng WANG Guang XUE Qing-guo 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2013年第5期28-33,共6页
The kinetics of isothermal reduction of the carbon bearing pellets, which were mainly composed of Bayanobo complex iron ore and pulverized coal, was investigated by thermogravimetry at the temperature of 1 273-1 673 K... The kinetics of isothermal reduction of the carbon bearing pellets, which were mainly composed of Bayanobo complex iron ore and pulverized coal, was investigated by thermogravimetry at the temperature of 1 273-1 673 K. The effects of xC/xO and the atmospheres on the extent of reduction also were investigated. The results indicate that the fractional reaction increased proportionally with temperature increasing and heating temperature is the significant influence factor to the reaction of carbon bearing pellets. The optimum xC/xO is 1.2 and the effect of atmosphere on the reduction of iron oxides is almost negligible. The results can be interpreted that the reaction was initially controlled by a mixed controlled mechanism of carbon gasification and interface chemical reaction, and in the later stage, interface chemical reaction became the rate-controlling step. Apparent activation energy values of reduction at different levels of fractional reaction were calculated. Before F (fraction of reaction)=0.5, the apparent activation energy ranges from 66.39 to 75.64 kJ/mol, while after F=0.5, the apparent activation energy is 80.98 to 85.37 kJ/mol. 展开更多
关键词 Bayanobo complex iron ore carbon bearing pellet THERMOGRAVIMETRY apparent activation energy
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Comprehensive Utilization of Paigeite Ore Using Iron Nugget Making Process 被引量:18
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作者 DING Yin-gui WANG Jing-song +2 位作者 WANG Guang MA Sai XUE Qing-guo 《Journal of Iron and Steel Research International》 SCIE CAS CSCD 2012年第6期9-13,共5页
The feasibility of paigeite ore treatment with iron nugget making process is proved. The isothermal reduc- tion experiments at laboratory scale were carried out, using carbon bearing pellets which were made of boron c... The feasibility of paigeite ore treatment with iron nugget making process is proved. The isothermal reduc- tion experiments at laboratory scale were carried out, using carbon bearing pellets which were made of boron contai- ning iron concentrate and pulverized coal mainly, from 1 623 to 1 723 K with different heating time. The results indi- cated that iron nugget making process depends mainly on heating time and temperature. And the iron nugget and slag can separate in a clean manner at 1 673 K for 15 min. For the iron nugget, the C content is 3.57% (mass percent) and B is 0. 065~ (mass percent). The B203 content of slag is 20.01~/00, and the boron was concentrated into one phase which is identified as suanite (Mg2BaOs) during the solidification. With an extraction ratio of 80~ under the atmospheric conditions, the activity of boron in slag is good. The boron-rich slag can be used to extract boric or boric acid and alleviate the shortage of boron resource. Through series of calculation and analysis related, it can be conclu- ded that the recovery ratio of Fe and boron are about 98% and 97% respectively. The results show that this method is feasible and effective on the utilization of paigeite ore. 展开更多
关键词 boron containing iron concentrate carbon bearing pellets iron nugget boron-rich slag
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