Reactivity and Conversion Behaviour of Brazilian and Imported Coals, Charcoal and Blends in view of their Injection into Blast Furnaces

Machado, Janaína G M S; Osório, Eduardo; Vilela, Antônio Cezar Faria; Babich, Alexander; Senk, Dieter; Gudenau, Heinrich Wilhelm

doi:10.1002/srin.200900093

Cited by 58 publications

(29 citation statements)

References 21 publications

(23 reference statements)

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“…The possibility that interactions between the mineral matter of the BC and CC coals has hindered the access of the gas to the char should not be excluded. Machado 2009 showed that large reductions in the ash fusion temperatures occurred when Brazilian coal was mixed with biomass 26 . In the cases in which CC is mixed with the highest rank coals (ICA and ICB), the experimental curve shows a lower conversion than the calculated one in the first steps of CO 2 gasification (Figure 3 curves b and c).…”

Section: Study On Behaviour Of Coals Charcoal and Mixtures Using Tgamentioning

confidence: 99%

Reactivity of brazilian coal, charcoal, imported coal and blends aiming to their injection into blast furnaces

2010

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For about 10 years the steel industry in Brazil has used pulverized coal injection (PCI) technology in the blast furnaces based on imported coals. In order to decrease the dependence on imported coals, Brazilian coal, which has limited use due to high ash content, was suggested to be mixed with imported coal and charcoal. The aim was to examine the reactivity of the samples. The charcoal use in the steel industry contributes to the CO 2 emission reduction, since it represents a renewable source of energy. The reactivity of the coals, charcoal and mixtures was evaluated through simultaneous thermal analyses. Results of this study are presented and discussed.

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Section: Study On Behaviour Of Coals Charcoal and Mixtures Using Tgamentioning

confidence: 99%

Reactivity of brazilian coal, charcoal, imported coal and blends aiming to their injection into blast furnaces

2010

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“…4,5) First studies on charcoal and charcoal-ore fines mixture injection were carried out by RWTH Aachen University in co-operation with Mannesmann S.A. (MSA) Brazil on a laboratory rig in Aachen and at a charcoal blast furnace in Belo Horizonte (inner volume 474 m 3 , hearth diameter 5.5 m). 6) Results showed feasibility of this technology but raised problems concerning the charcoal behaviour in and outside of the raceway.…”

Section: Introductionmentioning

confidence: 99%

Charcoal Behaviour by Its Injection into the Modern Blast Furnace

Babich

Senk

Fernández³

2010

ISIJ Int.

126

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Nowadays the use of charcoal in metallurgy is intimately linked to small blast furnaces in Brazil. Due to the challenge for CO 2 mitigation, interest for charcoal use as a renewable energy source is rising. In the scope of European efforts to mitigate carbon dioxide emissions in the steel industry in the post-Kyoto period, the use of charcoal in cokemaking and ironmaking has been investigated. This paper presents results of an experimental study on charcoal behaviour under the blast furnace simulating conditions performed at the Department of Ferrous Metallurgy, RWTH Aachen University and at the National Centre for Metallurgical Investigations, Madrid. Conditions in the raceway and in the furnace shaft were simulated using thermo-analytical, laboratory and pilot facilities. Charcoal samples were produced in two furnaces for pyrolysis from different wood types at various carbonisation conditions. Furthermore technological and ecological assessment of blast furnace process when injecting different types of charcoal was performed using a mathematical model. All the experiments and calculations were also performed with reference mineral coals for injection. Conversion efficiency of all the tested charcoals is better or comparable with coals. Change in coke rate, furnace productivity and further operation parameters when replacing pulverised coal with charcoal depends on charcoal ash content and composition.KEY WORDS: blast furnace; charcoal injection; CO 2 emission; raceway simulation; secondary consumption. 81© 2010 ISIJ coal Brazilian furnaces not only in terms of larger dimensions and higher operational parameters but also in terms of in-furnace reaction conditions: the chemical reactivity of coke is significantly lower compared with charcoal and Boudouard reaction occurs in the coke blast furnace at higher temperatures. Therefore the degree of indirect reduction in the furnace shaft is higher and consequently carbon monoxide content in top gas and its calorific value are lower. Effect of charcoal injection on large blast furnaces and at high injection rates was studied up to now mainly by mathematical modelling. 7) There are also studies on waste wood use for producing metallurgical coke and for BF injection, 8,9) but the raw wood is difficult to be grinded, because it is composed of rigid structure of cellulose and lignin.10) In Ref. 10) a study was done on biomass injection. In this work, firstly technological and ecological assessment of BF operation when injecting charcoal was conducted using a mathematical model. Afterwards, laboratory and pilot injection trials, microscopic study as well as tests using thermal analysis were carried out to investigate the charcoal behaviour under the blast furnace raceway simulating conditions. Furthermore solution loss reaction of charcoal in the furnace shaft was investigated to evaluate the possibilities of secondary utilisation of charcoal outside the raceway. Effect of charcoal on coke reactivity was studied as well. Injection of PC used in the industrial blast furnace...

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“…The use of charcoal in composite briquettes, sourced from sustainable biomass resources, could be a convenient way of introducing renewable carbon into the iron-making process. Charcoal has a lower ash content than coal and the ash is normally less acidic, i.e., it has a relatively high CaO/SiO 2 ratio [5].…”

Section: Introductionmentioning

confidence: 99%

“…(5) and (6). Equation (5) indicates that stoichiometric reduction of hematite would require a C/Fe mass ratio of 0.161. However, at typical reaction temperatures and with some available carbon to react with CO 2 via Eq.…”

Section: Introductionmentioning

confidence: 99%

The Strength and Density of Green and Reduced Briquettes Made with Iron Ore and Charcoal

Somerville

2016

J. Sustain. Metall.

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Composite briquettes or pellets consisting of iron ore, carbon, and a binder are a source of direct reduced iron (DRI). In the handling of green and reduced briquettes, high strength is important to minimize briquette breakdown. The use of charcoal as a source of carbon, rather than coal provides a way of introducing renewable carbon into the ironmaking process. Composite briquettes were made with Australian hematite iron ore, low volatile charcoal and 2 % starch as a binder. The carbon-to-iron mass ratio was varied between 0.18 and 0.26. The green briquettes were heated to either 1300 or 1350°C for times varying from 3 to 15 min. After heating, the briquettes were tested for compressive strength, density, and the degree of iron metallization. The aim of the work was to determine the key strength forming features of the briquettes during heating and reduction. Dried green briquettes, made with a starch binder, were found to be very strong and required a force of at least 3800 N to yield under compression. After heating for 3 min, the briquettes lost strength rapidly before regaining strength at longer heating times of 10 and 15 min. Increasing the C/Fe ratio in the briquette mix decreased the strength and density, and increased the iron metallization of the heated briquettes. Briquette strength also increased with increasing time from 10 to 15 min and heating temperature from 1300 to 1350°C. These observations can be explained in terms of the distance between iron oxide particles in the briquette mix. At low C/Fe ratios, iron oxide particles will be relatively close together which facilitates the development of a connected slag network which acts as a binder and increases briquette strength.

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Reactivity and Conversion Behaviour of Brazilian and Imported Coals, Charcoal and Blends in view of their Injection into Blast Furnaces

Cited by 58 publications

References 21 publications

Reactivity of brazilian coal, charcoal, imported coal and blends aiming to their injection into blast furnaces

Reactivity of brazilian coal, charcoal, imported coal and blends aiming to their injection into blast furnaces

Charcoal Behaviour by Its Injection into the Modern Blast Furnace

The Strength and Density of Green and Reduced Briquettes Made with Iron Ore and Charcoal

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