Comparative Study on the Combustion Performance of Coals on aPilot-Scale Test Rig Simulating Blast Furnace Pulverized CoalInjection and a Lab-Scale Drop-Tube FurnaceHongyu Li,, Liza Elliott, Harold Rogers, and Terry Wall*,

Chemical Engineering, University of Newcastle, Newcastle, New South Wales 2308, AustraliaSchool of Materials and Metallurgy, University of Science and Technology Liaoning, Anshan 114001, Peoples Republic of ChinaBlueScope Steel, Port Kembla, New South Wales 2505, Australia

ABSTRACT: Direct evaluation of the combustibility of pulverized coals in ironmaking blast furnace pulverized coal injection(PCI) is difficult. A pilot-scale PCI rig may be used to test the combustion performance of a PCI coal. However, the replicationof the conditions in the blowpipetuyereraceway region is complicated and costly. Drop-tube furnaces (DTFs), which havebeen widely used in coal combustion research, are seen as an alternative to such combustion tests. This study therefore comparescoal combustion performances in a DTF and a PCI rig, where the coal is burned at the as-ground size distribution to assess thesuitability of a DTF to replace a PCI rig. In addition, this study tries to establish the methodology for ranking the PCI coalcombustion performance through coal burnouts produced in the DTF. The measured burnouts from both the DTF and thepilot-scale PCI rig produced a linear relationship against the coal volatile matter (VM) content, although the trend of the DTFburnouts have a steeper slope. The burnouts of the two low-volatile coals (coals 1 and 2) stand outside the band and hadsignificantly higher burnouts in the PCI rig but not in the DTF. This is attributed to higher char fragmentation duringcombustion in the PCI rig. Overall, the data in this study suggest that cheap lab-scale DTF tests can be a good substitute ofexpensive tests using a pilot-scale PCI rig for the evaluation of PCI coals.

1. INTRODUCTION

Pulverized coal has been routinely injected into ironmakingblast furnace tuyeres as an auxiliary fuel for around 40 years,following the oil crisis in the 1970s. It reacts with pressurizedblast at a high temperature until it is burnt out or the residualchar leaves the raceway. This technology reduces costs andimproves blast furnace productivity. However, the injection rateis limited by the coal combustion performance. If the injectedcoal combusts efficiently, a high injection rate may be appliedto reduce the amount of coke required. However, unburnt charleaving the raceway increases significantly with an increasinginjection rate because of a decreasing coal burnout and candecrease the permeability of a blast furnace burden column. Acombustion test is a safe alternative to optimize coal selectionfor pulverized coal injection (PCI) in a blast furnace andminimize negative impacts on the blast furnace operation.Pilot-scale PCI test rigs, Aachen-type rigs, and drop-tube

furnaces (DTFs) have been previously used to evaluate thecombustion performance of PCI coals.13 PCI rigs are designedto simulate the injection of coal into a blast furnace, includingcoal injection into the blast passing through the blowpipetuyere system, jet expansion, and combustion as it passes acrossthe void space of the raceway. The thermal and chemicalconditions of the blast are set to model as closely as possiblethose of actual blast furnaces (such as blast temperature, oxygencontent, and velocity). Early types of these rigs were describedby Kobe Steel4 and Nippon Steel5 in the development ofmodern PCI technology. Broken Hill Proprietary, Ltd. (BHP),later BlueScope Steel, developed and operated a number ofsuch pilot-scale test rigs for PCI coal research between 1983

and 2008, and a large number of coals have been tested, withsome results being presented in the public domain.610

The Aachen-type3 bench-scale test rig was developed in the1980s11 and used to simulate the behavior of fine coal particlesinjected into the blowpipetuyereraceway region. This rigcomprises two furnaces in series. The first furnace produces hotgas as blast, and the other furnace is the combustion chamber.These rigs have limited availability, and the test results aredifferent to the results from the pilot-scale PCI rigs.3

Alternatively, a DTF is a very common piece of equipment incoal research laboratories and has also been used to test coalcombustion for PCI applications.2,12,13 In comparison to otherlaboratory combustion apparatuses, such as a thermogravi-metric analyzer and a wire mesh reactor, it can produce arelatively high temperature (1800 K) and a high heating rate(104 K/s). The particles are fed in a dynamic, dilute phase,which allows for individual and cloud particle combustion. Inthis kind of reactor, both solid and gaseous products aremeasured downstream from the feeding port. Lu et al.13 used aDTF with temperatures from 900 to 1500 C to produce charfrom pulverized coal before characterizing it, suggesting thatchar produced in a DTF would be similar to that in PCI. Du etal.2 studied the influences of the reaction temperature, coalparticle size, fuel ratio (defined as the ratio of fixed carbon to

Special Issue: 4th (2013) Sino-Australian Symposium on AdvancedCoal and Biomass Utilisation Technologies

Received: July 31, 2013Revised: October 27, 2013Published: October 28, 2013

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volatile matter), and coal blending on the burnout of pulverizedcoal in a DTF at the temperature range of 11001400 C.Their findings indicated that the combustion behavior of coalsdepends upon not only the gas temperature but also theparticle size.Significant differences exist in the configuration and

combustion conditions between a PCI rig and a DTF. Nocomparison of coal combustion results from them has beenpreviously published in the literature. The purpose of this workis therefore to (1) compare the combustion performance of arange of coals combusted in the two rigs with typical particlesize distributions of PCI, (2) establish the methodology to findif the ranking of the PCI combustion performance can bepredicted by DTF tests on the same coals with DTF burnoutscovering a similar range as the available PCI burnout data, and(3) identify coals not fitting the ranking of combustionperformance by the DTF and suggest reasons.

2. EXPERIMENTAL SECTION2.1. Coal Samples. Seven coals, previously used in tests on the

PCI rig by BlueScope Steel, were selected. They are suitable for PCIuse or have been considered for PCI use. These coals were cold-storedafter the PCI tests and were made available for the DTF tests in thisstudy, except coals 1 and 2, which were replaced with fresh samplesfrom the same mines with matching ultimate, proximate, andpetrographic analyses. The proximate and ultimate analyses for eachcoal are listed in Table 1.2.2. Experimental Apparatus and Methods. 2.2.1. Pilot-Scale

PCI Test Rig. The pilot-scale PCI test rig considered here was operatedbetween 2001 and 2008 at BHP Billitons Research Laboratories inNewcastle,3 and the burnouts presented in this work were taken fromthose tests. The PCI rig consisted of a refractory cylindrical testsection. Air, heated using a resistance heater and a N2 plasma torch to1200 C, was injected into the combustion chamber at up to300 N m3 h1 as blast. The blast was introduced through a duct with areducing internal diameter from 110 to 80 mm over a length of 800mm upstream of a tuyere, where coal is injected. After the tuyere, theinternal diameter increased dramatically, allowing for a free expansionof the gas jet. Pulverized coal was injected into the blast at the center

of the tuyere inlet via a coaxial injection lance, which was inclined at anangle of 1012 to the blast duct center line. The coaxial lanceconsisted of a 19.05 mm (outer diameter) 1.6 mm wall thicknessouter tube, which carried a cooling gas of air, and a 12.7 mm (outerdiameter) 1.6 mm wall thickness inner tube, through which coal wasconveyed by a nitrogen stream. Coal injection rates of 2569 kg/hwere used, and the blast oxygen concentration was correspondentlyincreased from 21 to 26%. The test conditions were chosen to matchas closely as possible the conditions within the blowpipetuyereraceway region of blast furnaces. Char samples were collected by awater-cooled argon-quenched probe at port 5 (925 mm downstreamof the injection point) at the center-line position and 50 mm oneither side of the center line. The estimated particle residence time was20 ms, which is equivalent to the predicted transit time of a coalparticle across the raceway in the blast furnace.9 The rig layout ispresented in Figure 1.

2.2.2. DTF. An Astro model 1000 DTF was used for the burnouttest experiments. Furnace operation is controlled by a Honeywellmodel DCP 511 temperature controller/program. A schematicdiagram of the experimental setup for the DTF is shown elsewhere.14

The central tube (50 mm inner diameter) is made from recrystallizedalumina and is heated externally using a graphite heating element (62mm inner diameter and 300 mm in length). The hot zone of thefurnace is 255 mm in length and is able to be maintained at a relativelyuniform temperature (50 C). The oxygen concentration used in theexperiments varied between 21 and 26%. Mass flow controllers wereused to produce the correct flow rate of oxygen and nitrogen beforethe two gases were mixed. The experiments were completed withoxygen concentrations that matched those in the PCI tests. When 21%oxygen was required, air from a Kaeser Ask27 facility compressor wasused. The gas was then split between primary (4.5 L/min) andsecondary (5.3 L/min) gas flows. Coal was fed at a rate of around4 g/h through a vibrating plate enclosed in an airtight perspex boxabove the DTF. The primary gas assisted feeding the coal into the topof the furnace through a small funnel and water-cooled feeding probe.The secondary air stream was preheated as it entered the furnacethrough the annulus between the central tube and the Kaowool heatshield on the feeding probe. Char samples were collected at the base ofthe furnace hot zone by a water-cooled collection probe with nitrogengas quenching. A vacuum was applied to withdraw the char, quenchgas, and combustion gases out of the furnace. The char sample was

Table 1. Coal Properties

coal 1 2 3 4 5 6 7

proximate analysis (%) M (ad) 1.4 1.6 1.1 2.2 2.6 3.5 6.7VM (db) 13.0 13.6 18.4 27.5 28.4 36.2 41.7FC (db) 77.4 78.0 71.2 63.1 68.9 55.6 53.4ash (db) 9.6 8.4 10.4 9.4 2.7 8.2 4.9

ultimate analysis (%) C (db) 80.8 81.6 80.3 76.4 81.4 76.9 77.9H (db) 3.6 3.7 4.0 4.3 4.7 5.1 5.5N (db) 1.5 1.8 1.4 1.6 1.2 1.8 1.4S (db) 0.4 0.5 0.3 0.4 1.2 0.4 0.3O + errors (db) 4.1 4.0 3.6 7.9 8.8 7.6 10.0

Figure 1. Schematic layout of the combustion test apparatus.16

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removed from the gas stream via a cyclone and aerosol filter. Theorganic matter in the sample was determined by burning a portion ofthe sample with air at 815 C in a muffle furnace until a constantweight was attained. Then, the weight of the remaining ash wasmeasured, and the unburnt organic matter content of the charproduced in the DTF was calculated.2.3. Major Differences of the Two Rigs. The major differences

between the two rigs are summarized in Table 2. In this study, the gas

temperature in the DTF was set at 1450 C. The furnace had acalculated residence time of 210 ms and a heating rate of 24 104K/s. On the other hand, the maximum gas temperature in the PCIplume combustion is estimated to be more than 2000 C, with acalculated heating rate and a residence time of 105 K/s and 20 ms,respectively.15,16

The oxygen partial pressure provided during combustion differedgreatly in the two rigs. Stoichiometry of pulverized coal combustion isbased on reaction 1.

+ =C O CO2 2 (1)

The O/C ratio, which is based on the atoms of oxygen fed per atom ofcarbon, is often used to describe combustion conditions. This has avalue of 2 for stoichiometric combustion, greater than 2 for excessoxygen, and less for sub-stoichiometric conditions.In the DTF, operating with a dilute feed of coal, significantly excess

oxygen exists. The oxygen concentration does not reduce significantlyduring combustion; all of the coal particles burn in a consistent gasatmosphere. The O2 concentration of the feed gas therefore uniquelydefines the combustion conditions, these being 21 (i.e., air), 22.6, and26% in the present study. The conditions in the PCI rig were assignedto duplicate those of an operating blast furnace. The O/C ratio wasaround 3.2 (2.83.6 for the range of coals) when firing with air, about2 with an O2 concentration of 22.6% of the feed gas (1.72.5 for therange of coals), and approximate 1.4 with an O2 concentration of 26%of the feed gas (1.21.6 for the range of coals). The decline of O/C isbecause the coal injection rate was increased without a change in thevolume of the blast (i.e., gas). Therefore, for the PCI rig, the O2concentration of the feed gas does not uniquely define the combustionconditions.The flame conditions were also significantly different in the two rigs.

In the DTF, coal was fed as a disperse phase in the primary (feeding)gas stream. Particles were expected to burn individually, whereas in thePCI rig, coal was injected through the blowpipe into the blast,producing a highly turbulent plume. These differences of conditionsand configurations significantly impact the combustion performance ofcoals.2.4. Analysis of Particle Size Distribution. The particle size

distribution of coals and chars collected from the PCI rig and the DTFwere measured by a Malvern 2600 particle size analyzer.

3. RESULTS AND DISCUSSIONThe ash tracer method was used to determine coal burnout inboth the DTF and the PCI rig. It assumes that the mass of ashin a coal is conserved as the volatile portion of the coal is

released and the carbon of the coal is combusted. The coalburnout (combustion efficiency) was determined by eq 217

=

B

AA

AA

11

1100i

i

0

0 (2)

where B is the burnout and A0 and Ai are the ash content incoal and char, respectively.During the DTF experiments, five samples of each coal were

fed and chars were collected and ashed separately. Figure 2

shows the average coal burnout with the range of experimentalvalues at 21% O2 as a function of the coal volatile matter (VM)content. The burnout increases with an increasing VM [drybasis (db)] content. The highest VM coal presents themaximum burnout of 86.8%, and the minimum value of24.1% was produced by the lowest VM coal.The burnouts of coals produced in the DTF at different O2

concentrations from 21 to 26% are shown in Figure 3. These

results increase monotonically with an increasing coal VMcontent at all O2 concentrations; that is, VM is a dominateindicator of the coal combustion performance in DTFconditions. In addition, burnout increases with enhancementof the O2 concentration in the DTF experiments, but theamount of increase varies among the coals. Coal 2 (13.6% VM)and coal 5 (28.4% VM) show a large increase. However, coal 4(27.5% VM) and coal 6 (36.2% VM) are weakly influenced by

Table 2. Combustion Conditions in the DTF and the PCIRig

technique DTF PCI rig

particle heating rate(K/s)

104 (ref 2) 105 (ref 15)

peak gas temperature(C)

1450 >2000

residence time (ms) 210 20 (ref 16)flame conditions laminar dispersed

particlesturbulent, high particledensity coal plume

stoichiometry and O2concentration

significant excessoxygen

approximately stoichiometric

Figure 2. Burnout of coals in the DTF experiments at 1450 C and21% O2.

Figure 3. Coal burnouts in the DTF as a function of VM at differentO2 concentrations at 1450 C and () 21% O2, () 22.6% O2, and() 26% O2.

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the O2 concentration. Thus, coal burnout is influenced by boththe coal VM content and O2 concentration.The burnouts produced in the PCI rig are shown in Figure 4.

They vary between 41.3 and 78.7% with an increasing VM.

Coal 3 produced the lowest burnout at 22.6% O2, and thehighest value was obtained by coal 7 at 21% O2. Coals 1 and 2show excellent combustion performance, which cannot beexplained by the proximate analysis. Furthermore, the figurealso shows that the PCI burnouts decrease with an increasingoxygen concentration. The higher burnouts were commonlyobtained when the oxygen concentration was at 21%, and thelower results were mostly obtained at the highest O2concentration (26%). This is due to the effect of O/C at thedifferent O2 levels on burnout detailed in section 2.3. The O2supply is not expressed by the O2 concentration but the ratio ofO/C. A high O2 concentration in the PCI rig tests does notresult in more O2 available because of a simultaneous increasein the coal injection rate with the same blast volume. Thus, thehigher burnouts occurred at 21% O2 (high O/C).

18 In the PCIrig, coal burnout is a function of the coal injection rate and O/C ratio rather than the O2 concentration. However, the O/Cratios used in the PCI rig could not be replicated in the DTF.To clarify the combustion performances clearly within the

two rigs, the burnouts from the two rigs were compared at acorresponding oxygen concentration. A comparison of coalburnouts at 21% O2 is shown in Figure 5a. Two linear bandswith different slopes were obtained. Burnouts in the DTFincrease linearly from 24.1 to 86.8% with an increasing VM(db) from 13.0 to 41.7%, producing a steeper slope than thatfrom the PCI rig. The burnouts from the PCI rig increase from52 to 78.7% in the corresponding range of VM. Lower VMcoals produced lower burnouts in the DTF than the resultsfrom the PCI rig, but higher VM coals presented highercombustion performance. Coal 1 produced good performancein the PCI rig but sits at the bottom of the region whencombusted in the DTF. Coal 2 stands outside the highlightedrange of the PCI results, sitting higher than expected for a coalwith its VM. When it was combusted in the DTF, this coal sitswithin the expected range. Coals 3 and 5 sit along the bottomof the PCI band when combusted in the PCI rig, but they arealong the top of the DTF combustion region. The burnouts ofhigh VM coals (coals 6 and 7) in the DTF are higher than thosein the PCI rig and stand at the top of the trend.

The comparisons of the burnouts from the two rigs at 22.6and 26% O2 are given in panels b and c of Figure 5,respectively. Two bands with different slopes can be drawn inthese panels. Coal burnouts from the DTF increase withincreasing O2 concentrations. However, those from the PCI rigdecrease. Thus, the shaded band of the DTF results movesupward, and the band of the PCI results goes downward. Thetwo bands almost merge together at 22.6% O2. The band of theDTF burnouts is mostly over that of the PCI results at 26% O2.The slope of the DTF band of burnouts deceases slightly as theoxygen concentration increases. However, there is little changein the slope of the shaded band of the PCI results.The condition experienced by coal particles in the PCI rig

combined the characteristics of a higher temperature, higherheating rate, less residence time, and O/C ratios close tostoichiometry. Coal particles experienced a longer residence

Figure 4. Burnouts produced in the PCI rig at different O2concentrations as a function of VM at () coal injection rate (CR)= 24.9 kg/h, O/C = 3.2, and 21% O2; () CR = 40.6 kg/h, O/C = 2,and 22.6% O2; and () CR = 64.9 kg/h, O/C = 1.4, and 26% O2(some of these results appeared in refs 3, 16, and 18).

Figure 5. Comparison of burnout as a function of VM between theDTF at 1450 C and the PCI rig at O2 concentrations from 21 to 26%with shaded operating bands: (a) 21% O2, (b) 22.6% O2, and (c)26% O2.

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time, excess O2, and lower temperature and heating rate in theDTF. Consequently, different operation bands were obtained.Because different combustion efficiencies of the same coal wereobserved in the two rigs, the differences may be attributed tothe different configurations and combustion conditions inthem.19

Burnouts produced by coals 1 and 2 (low-volatile coals)during combustion in the PCI rig are significantly higher thanexpected with their VM contents. This may be attributed to thesmaller particle size distribution of the raw coal and higherfragmentation during combustion in the PCI rig.It is common knowledge that particle sizes impact the coal

combustion performance. Less time is taken by small particlesto reach a given burnout than large particles;20 i.e., smallparticles produce better combustion. The particle sizedistributions of coals are demonstrated in Figure 6. As seen,

coal 5 had the coarsest particles among these coals. Samples ofcoals 1 and 2 used in the PCI rig were aged and replaced bynewly mined samples for DTF experiments. These coals hadthe finest particle size distribution. Other coals had median sizedistributions for these samples. The particle size distributions ofresulting chars are shown in Figure 7 (chars from coals 4 and 5were consumed in other tests and were not available). There isno evidence to suggest that one rig produces consistently finerchars. The char particle size is a function of the coal particlesize, but different behaviors were observed from different coals

within the two rigs. The particle size distributions of coals 1 and2 and their chars are compared to the results of coal 7 and itschars in Figure 8.

It can be seen that coal 7 experienced greater swelling in thePCI rig, producing larger char than in the DTF, while theopposite trend was observed for coals 1 and 2. Fragmentationof chars from coals 1 and 2 in the PCI rig is believed to causethe chars to be substantially finer. Within the mass-transfer-controlled regime expected at a high temperature, the charburning time is inversely proportional to the particle size,20

which may explain why the burnouts of coals 1 and 2 in thePCI rig are significantly higher than expected. Lessfragmentation of the same coals in the DTF resulted in lowerburnouts, falling within the band with the other coals.Considering laboratory-scale rigs for coal testing, a

comparison of characteristics in these rigs is shown in Table3. In comparison to common laboratory-scale rigs, theadvantages of low cost, easy operation, and good predictionare obviously observed in a DTF. Although there is hot airinjection in the Aachen-type rig, the measured burnouts arequite different compared to the results from the PCI rig.3 Thepeak temperature (normally 1273 K) and heating rate

Figure 6. Particle size distribution of coals.

Figure 7. Particle size distribution of chars obtained from the DTF at1450 C and 21% O2 and from the PCI rig at 21% O2.

Figure 8. Particle size distribution of (a) coals 1, 2, and 7 and (b)chars from the DTF and the PCI rig. The same coal sample was usedin the PCI rig and the DTF for coal 7, but different coal sizedistributions for coals 1 and 2. Chars were obtained from the DTF at1450 C and 21% O2 and from the PCI rig at 21% O2.

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(maximum of 50 K/min) of thermogravimetric analysis (TGA)are much lower than that in the PCI condition, and thecombustion occurs in a fixed bed. Therefore, a laboratory-scaleDTF is a good substitute of a pilot-scale PCI rig in theevaluation of PCI coals.The limited number of coals presently used to obtain the

operating region has not outlined the band definitely. Datafrom more coals are required to evaluate the use of a DTF forthe prediction of performance of any new coals for PCI.Further investigations of volatile release under PCI conditionsand the resulting char burnout are required. An on-goingmodeling study by the authors will further clarify the differencein combustion performance of coals in the two rigs and will bereported in the future.

4. CONCLUSION(1) The burnout of coals over a range of VM contents duringcombustion in both the DTF and the PCI rig increases almostlinearly with an increasing coal VM content. The burnout ofcoals during combustion in the DTF is more sensitive to coalVM content. In this study, DTF tests can provide a reasonableindication of coal combustion performance in the PCI rig formedium (18.4%, db) to high (41.7%, db) volatile coals. (2) Theburnouts of the two low-volatile coals (coals 1 and 2) standabove the band for other coals, have significantly higherburnouts in the PCI rig than expected, but fit well in theburnout band in the DTF. This is attributed to charfragmentation during combustion in the PCI rig, resulting insmaller char particle size distributions and, hence, greater charburnout.

AUTHOR INFORMATIONCorresponding Author*E-mail: terry.wall@newcastle.edu.au.NotesThe authors declare no competing financial interest.

ACKNOWLEDGMENTSThe authors thank BlueScope Steel for financial support andprovision of PCI combustion results, chars, analysis data, andcoals. The authors also thank the Australian Research Council(ARC) and the Australian Coal Association Research Program(ACARP) for financial support.

REFERENCES(1) Ueno, H.; Yamaguchi, K.; Kenji, T. ISIJ Int. 1993, 33, 640645.(2) Du, S. W.; Chen, W. H.; Lucas, J. A. Energy 2010, 35, 576581.(3) Rogers, H.; Wall, T. Review of Ironmaking Blast Furnace PulverisedCoal Injection Combustion Testing; Australian Coal AssociationResearch Program (ACARP): Brisbane, Queensland, Australia, 2011;Project C19049.

(4) Suzuki, T.; Hirose, R.; Morimoto, K.; Abe, T. Symp. (Int.)Combust., [Proc.] 1984, 14191425.(5) Masakazu, N.; Kojima, K.; Hara, Y.; Kase, M. Influence of cokequality on blast furnace performance. Proceedings of the 38thIronmaking Conference; Detroit, MI, March 2528, 1979; pp 1827.(6) McCarthy, M. J.; Mathieson, J. G.; Nomura, S.; Rogers, H.Combustion of pulverised coals under simulated blast furnaceconditions. Proceedings of the International Conference on Coal Science;Sydney, New South Wales, Australia, Oct 2831, 1985; pp 423426.(7) Keating, J.; Mason, M.; Rogers, H. Combustion testing ofpulverised coal for blast furnace tuyere injection. Proceedings of the JointConference of SCENZ/FEANZ/EMG; Auckland, New Zealand, April910, 2001.(8) Haywood, R. J.; McCarthy, M. J.; Truelove, J. S.; Mason, M. B.;Thomson, A. D. An experimental and theoretical investigation ofpulverised coal combustion in blast furnaces. Proceedings of the FourthAustralian Flame Days; Adelaide, South Australia, Australia, Nov 910,1995.(9) Mathieson, J. G.; Trueove, J. S.; Rogers, H. Fuel 2005, 84, 12291237.(10) Scaife, P.; Mathieson, J.; McCarthy, M.; Rogers, H.; Nomura, S.Replacement of Oil by Coal Injection at the Blast Furnace; NationalEnergy Research, Development and Demonstration Council(NERDDC): Canberra, Australian Capital Territory, Australia, 1983;NERRD Project 79/9185.(11) Machado, J. G. M. S.; Osorio, E.; Vilela, A. C. F.; Babich, A.;Senk, D.; Gudenau, H. W. Steel Res. Int. 2010, 81, 916.(12) Osorio, E.; de Lourdes Ilha Gomes, M.; Vilela, A. C. F.;Kalkreuth, W.; de Almeida, M. A. A.; Borrego, A. G.; Alvarez, D. Int. J.Coal Geol. 2006, 68, 1429.(13) Lu, L.; Sahajwalla, V.; Kong, C.; Mclean, A. ISIJ Int. 2002, 42,816825.(14) Li, X.; Rathnam, R. K.; Yu, J.; Wang, Q.; Wall, T.; Meesri, C.Energy Fuels 2009, 24, 160164.(15) Haywood, R. J.; Truelove, J. S.; McCarthy, M. J. Modelling ofpulverised coal injection and combustion in blast furnaces. Proceedingsof the Ironmaking Conference of AIME; Warrendale, PA, 1994; pp 437442.(16) Mathieson, J. G.; Rogers, H.; Somerville, M. A.; Jahanshahi, S.ISIJ Int. 2012, 52, 14891496.(17) Su, S.; Pohl, J. H.; Holcombe, D.; Hart, J. A. Prog. EnergyCombust. Sci 2001, 27, 7598.(18) Rogers, H.; Mathieson, J. G.; Mason, M. B. The impact of coalpetrographic composition on the combustion of pulverised coals undersimulated blast furnace tuyere injection conditions. Proceedings of theCHEMECA 2011; Sydney, New South Wales, Australia, Sept 1821,2011.(19) Li, H.; Elliott, L.; Rogers, H.; Austin, P.; Jin, Y.; Wall, T. EnergyFuels 2012, 26, 46904695.(20) Field, M. A.; Gill, D. W.; Morgan, B. B.; Hawksley, P. G. W.Combustion of Pulverised Coal; British Coal Utilisation ResearchAssociation (BCURA): Leatherhead, U.K., 1967.

Table 3. Comparison of Coal Test Rigs

type scale operationoperation

cost comments

PCI rig pilot difficult andcomplicated

high closest simulation of PCIand linear increasingtrend

Aachentype

bench normal medial level trend, different toPCI rig3

DTF bench easy low linear increasing trendTGA bench easy quite low low-temperature

fixed-bed combustion

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mailto:terry.wall@newcastle.edu.au