Steam Reforming of Tar Using Low-Grade Iron Ore for Hydrogen

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Biofuels and Biomass

Steam reforming of tar using low grade iron ore for hydrogen production Rochim Bakti Cahyono, Marwan Bin Mansor, Takahiro Nomura, Muslikhin Hidayat, Arief Budiman, and Tomohiro Akiyama Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.8b04122 • Publication Date (Web): 22 Jan 2019 Downloaded from http://pubs.acs.org on January 27, 2019

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Steam reforming of tar using low grade iron ore for hydrogen production Rochim B. Cahyonoa,*, Marwan bin Mansorb, Takahiro Nomurab, Muslikhin Hidayata, Arief Budimana, Tomohiro Akiyamab a Department

of Chemical Engineering, Universitas Gadjah Mada, JI. Grafika 2, Bulaksumur,

Yogyakarta 55281, Indonesia b Center

for Advanced Research of Energy Conversion Materials, Hokkaido University, North 13

West 8, Kita-ku, Sapporo 060-8628, Japan

*CORRESPONDING AUTHOR Tel: +62-274-6492171; Fax: +62-274-6492170 E-mail: [email protected]

ACS Paragon Plus Environment

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Abstract In the gasification process, tar material may cause operational problems such as carbon deposition over catalyst, pipe plugging, condensation, and tar aerosol formation. Unusual approaches should be introduced to solve carbon deposition over catalyst which was serious problem in tar decomposition process. The utilization of low grade iron ore as catalyst and effect of adding steam in the tar reforming process were evaluated through this study. Due to insufficient energy to remove the OH group at the dehydration below 200oC, the generation of pores within iron ore was still incomplete. In other hand, the generation of pores increased rapidly between 200-300oC which was indicated by rising of BET surface area. The phase of iron ore was changed along the process and may increase the catalyst activity during reforming process. The utilization of low grade iron ore in the steam reforming of tar increased significantly the total gas production especially H2 and CO2. This was due to the porous iron ore was able to provide the high surface area for tar decomposition reaction. The addition of steam into tar decomposition reaction increased gas product and declined carbon formation. The excessive increasing of gas production occurred at the decomposition of 800oC such as H2, CO and CH4. Therefore, steam reforming using low grade iron ore was promising candidate to solve the tar material problem

KEYWORDS: steam reforming, low grade iron ore, tar decomposition, iron ore reduction.


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Energy & Fuels

1.

Introduction The solid fuels such as low grade coal and biomass could be utilized as promising energy

source through gasification process by producing char, liquid tar and gases in the specific values. While char and gas could be used directly as energy source, liquid tar as by-product may initiate problems during processes such as blocking of pipeline, tar condensation as well as tar aerosol formation [1-2]. This condition cause of cutting the overall efficiency and enhancing of maintenance cost during energy generation from biomass and low grade coal. The complete elimination of tar by changing into valuable gas and light chemicals are most essentials research subject in that field. Some approaches have been offered for removing of liquid tar from the pyrolysis-gasification system such as catalytic reforming and physical method [3-5]. One of common physical method is liquid scrubbing that the mixture of gas and liquid tar would be cooled down and separated between liquid tar and gas. By this process, thermal exergy of tar would be wasted and in the other hand would produce a waste liquid stream that must be treated for disposal. In contrast, tar decomposition through reforming process is more attractive by eliminating tar component and changing into gas product without producing a waste liquid stream. In order to obtain a complete tar decomposition, the reforming process highly requires catalyst that contains specific metal such as Pd, Pt, Ni and Rh [6-10]. Among those metals, nickel catalyst in various form has been shown better performance for reforming tar component of the coal or biomass pyrolysis process into valuable gas product. The Ni-Mo catalyst have eliminated nearly 100% of liquid tar component at 500oC and changed to various gas product [11]. However, the effectiviness of catalyst would be declined significantly by the present of carbon deposition on the surface of catalyst. Aznar et al [12] reported that typical nickel A catalyst is declined into 54% in term of activity for reforming of tar component during 35 hour experiment time. In addition to


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deactivation catalyst by carbon deposition, expensive raw material as well as catalyst regeneration method are other important issues related to the conventional metal catalyst. As an alternative to the expensive conventional metal-based catalysts, the catalyst development which based on the natural mineral is strongly needed to solve problem related to elimination of tar material by reforming process. Iron-based catalyst is one of the candidates which is cheaper than conventional metal-based catalysts (Ni, Pt and Pd) and also it is non-toxic. It is reported that iron-oxide-based catalysts such as Fe2O3-Al2O3 shows high activities to reform the tar component into hydrogen gas in the biomass pyrolysis process [13,14]. Tar is decomposed over the iron oxide catalysts followed by water gas shift reaction. Surface area of the iron oxide is the main factor during catalytic decomposition of biomass tar from pyrolysis process. Natural iron ore such as goethite ore is also suitable for biomass tar decomposition and producing valuable gas product during pyrolysis [15-16]. In our previous report [17-18], the decomposition of tar material was done over integrated pyrolysis-tar decomposition process that the volatile matter included tar component from biomass pyrolysis was introduced to fixed bed of porous iron ore for tar decomposition process. The tar decomposition results a huge valuable gas products (CO and H2), while the carbon deposits within the porous ore, simultaneously and initiates the catalyst deactivation. It is well known that the addition of steam into the reforming process increases the gas production especially H2 through water gas shift reaction. Therefore, this study focuses on a detailed evaluation of the effect of porous low grade iron ore as catalyst and steam addition on the gas production during tar decomposition process. In addition, the effect of temperature on the gas production was also discussed to further understand the catalyst activity of low grade iron ore.


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Energy & Fuels

2. Materials and experimental methods 2.1 Materials As carbon sources for decomposition process, liquid tar which originated from Japan ironmaking company was used during this study and the main components was shown in Table 1. It well known that the tar material was sticky, high viscosity and unmixed-well. Therefore to prevent the pipe clogging, pump problem and inhomogeneous material, the original tar was diluted with the toluene on ratio 60:40, respectively. As one of low grade iron ore, pisolite ore was examined as catalyst for tar decomposition and reforming process. Table 2 shows the major properties of the low grade iron ore. The availability of combined water within the ore would initiate the creation of a porous material through a simple dehydration process. The ore was crushed and sieved to attain a particle size less than 106 µm. 2.2 Experimental methods 2.2.1 Dehydration process In order to obtain the highest surface area and porous material, the dehydration process were proceed at different temperature (100-500oC) using constant heating rate of 3°C/min and a holding time of 1 hour in atmosphere condition. To examine the dehydration process; the surface area, average pore volume, and pore size distribution were measured before and after the experiment using a Brunauer-Emmett-Teller (BET) analyzer. The ore was also characterized using XRD analysis (Miniflex, Rigaku) to evaluate the changing on material phase.


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2.2.2 Steam reforming of liquid tar Figure 1 shows the experimental apparatus schematically which composed of constant flow rate of pump, gas flow controllers, reactor, cold trap and micro gas chromatography (GC) for monitoring gas composition in the outlet of reactor. Experiments were performed using a quartz reactor tube with an inner diameter and height of 30 mm and 550 mm, respectively. The electrical furnace was equipped with six thermocouples and temperature controller at the top, middle, and bottom. The temperature of top controller was fixed at 400oC to ensure complete evaporation of water while the middle controller was set up at the average of the top and bottom temperatures. The bottom thermocouple which was placed in the fixed bed of iron ore expressed the reaction temperature. Experiments were performed at atmospheric pressure with a total N2 flowrate of 100 mL/min. The tar and water were continuously added to the reactor, using a constant pump at flowrate of 0.5 mL/min for 20 min after the temperature of each controller became stable on the desired value. The steam was produced at the top of reactor and preheated to the decomposition temperature at the middle of reactor. The decomposition and reforming of tar occurred in the fixed bed of porous ore to produce various gases, carbon and lighter tar components. In the same time, the reduction of iron ore and carbon deposition inside the porous ore happened also in the fixed bed material. The product of tar reforming were allowed to flow through the cold trap which was maintained at –73°C to confirm complete separation of

liquid and gas product. The gas

composition was examined using micro GC while the characterization of iron ore was performed by XRD analysis and BET measurement. The carbon content within the iron was also examined using CHNO elemental analysis to evaluate the tar carbon deposition.


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2.2.3 Equilibrium composition using HSC Simulation In order to get the information regarding the equilibrium composition from steam reforming of tar, the commercial HSC software was used for the prediction. By using the tar composition data which similar to the experiment, the equilibrium composition data could be obtained.

The tar

composition was represented at Table 1.

3. Results and Discussion 3.1 Dehydration process Figure 2 (a) shows the changes in surface area and pore volume of iron ore as an effect of dehydration process at different temperature. The combined water (CW) within low grade iron ore was evaporated through reaction (1) and created porous material.

2FeOOH(s)  Fe 2 O 3 (s)  H 2 O(g); H  49.8 kJ/mol - Fe 2 O 3 at 450 C

(1)

The generation of pores was insignificant at the dehydration below 200oC due to insufficient energy to remove the OH group from the iron ore. Unlike the preceding part (below 200 oC), the generation of pore within iron ore increased rapidly between 200-300oC which is indicated by rising of BET surface area and pore volume. According to the previous TG data of iron ore, the removing of OH group which was showed by weight declining took place in this region. After 300oC, the generation of pore volume was steady and the decline continuously while the BET surface area was only increased slightly from 80 m2/g (300oC) into 90 m2/g (500oC), it denoted that only enhancing of 10 m2/g during 200 oC heating up. Therefore, the dehydration process at 300oC was chosen for tar decomposition experiment. Figure 2 (b) shows the XRD patterns of iron ore after dehydration process at different temperatures which were used to confirm the BET analysis data. Clearly, dehydration process at


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200oC was incomplete that was indicated by presenting of FeOOH within iron ore. This result agreed with the previous data which increasing of the BET surface area and pore volume was insignificant. The OH group still remained within iron ore and caused the generation of iron ore was imperfect. In contrast, the dehydration of CW at higher 200oC was sufficient to eliminate the OH group by converting the FeOOH to Fe2O3

3.2 Simulation of equilibrium composition Figure 3 shows the equilibrium composition of steam reforming of tar over Fe2O3 at different temperature using HSC simulation software. The phase of iron ore was changed along the different temperature and categorized into three regions. At below 400oC, the Fe2O3 altered to Fe3O4 by indirect reduction. The tar decomposition in this region resulted high amount of CH4 and carbon deposition. In the second region, between 400oC-700oC, the production of H2 and CO was started as result of tar decomposition. The carbon deposition decreased due to high gasification process at elevated temperature. The high amount of CO and H2 was sufficient to reduce the Fe2O3 into FeO. At above 700oC, the different behavior of gas production and iron ore phased were identified. The reforming of tar occurred completely to produce highest quantity of CO and H2 products and minimum amount of carbon deposition. This condition allowed generating of metallic Fe as final product of Fe2O3 reduction process. Beside as raw material of decomposition process, therefore tar material was potential as reduction agent. The phase of iron ore was changed along the process and may increase the catalyst activity during decomposition process.


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3.3 Steam reforming of liquid tar Figure 4 shows the effect of porous iron ore as a catalyst on the gas production during steam reforming of tar at 600oC. The reforming of tar would be proceed through the following reaction. Tar  H 2 O  H 2  CO  CO 2  CH 4  other light hydrocarbons  C (2) The thermal reforming produced only small amount of gas products. The different result was

showed in the reaction system that used porous ore as catalyst. The present of porous iron ore increased the significantly total gas production especially H2 and CO2 due to the catalytic activity. The porous iron ore provided the high surface area for tar decomposition reaction and resulting gas production. The catalytic reforming was predominant compared to the thermal process. Therefore, the porous low grade iron ore played important role in the steam reforming of tar. Figure 5 shows the effect iron ore on the changing of gas composition during steam reforming of tar at different time. Obviously, the presence of porous iron ore enhanced the total gas production around ninth times and altered the gas composition during the tar reforming. In the reforming without iron ore, the CO and CH4 were predominant as product of decomposition process. In contrast, the H2 and CO were major part of the gas production in the reforming over porous low grade iron ore. This phenomena was related to the catalyst selectivity and activity which CH4 decomposed and increased the amount of H2 and CO. The amount of H2 and CH4 showed opposite behaviour in the end of reaction time which associated to the activity of iron ore catalyst. Therefore, the decreasing of iron ore catalyst activity along the reaction time highly contributed on the changing of gas composition. Figure 6 shows the effect of steam addition on total gas production and amount of deposited carbon during tar reforming process over porous low grade iron ore at 600oC. Clearly, the addition of steam into tar reforming process slightly enhanced gas production except CH4 gas. Also, the


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presence of steam caused the declining of carbon deposition within iron ore, which might offer benefits through slow catalyst deactivation. The decreasing of CH4 composition after steam addition occurred due to steam reforming process which was catalyzed by porous low grade ore. It is well known that the reaction rate of steam reforming is higher that thermal reforming of tar material. Figure 7 shows the effect of steam addition on the changing of gas composition during tar reforming over porous low grade iron ore at different time. The total gas production enhanced around 8% volume as the result of steam addition. The addition of steam into the tar reforming process changed the gas composition and increased H2 and CO2 through water gas shift reaction as follow:

CO  H 2 O  CO 2  H 2

(3)

As previous result, the generation of H2 and CO2 was nearly constant in the end of reaction time due to decreasing of catalyst activity which was caused by carbon deposition. Figure 8 shows the effect of temperature on total gas production and amount of carbon deposition during tar reforming process over porous low grade iron ore. Generally, the gas production enhanced at elevated temperature due to thermal cracking activity. In contrast, the amount of carbon deposition reduced as a result of carbon gasification. The excessive increasing of gas production occurred at the decomposition of 800oC such as H2, CO and CH4. It is well known that thermal cracking, decarboxylation, and depolymerization are favored by an increasing of temperature. In addition, the both dry and steam reforming of CH4 started to occur above 800oC which increased the CO and H2 production. Figure 9 shows the changing of gas composition during tar reforming over porous low grade iron ore at two critical temperatures, 600 and 800oC. The total gas production increases


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Energy & Fuels

around twice at 800oC due to excessive thermal cracking. The gas composition of both temperatures showed similar tendency that H2 was predominant compared to other gasses. It related to the chemical bonding which was easy to break and form H2 from any type of hydrocarbon. As previous result, the profile of all gas production showed similar tendency which was nearly constant in the end of reaction time due to decreasing of catalyst activity.

4. Conclusions 1.

The dehydration process enhanced BET surface area and pore volume within low grade iron ore, especially at temperature range of 200-300oC. The generation of pores was still incomplete at the dehydration below 200oC due to insufficient energy to remove the OH group.

2.

The tar material was promising candidate of reduction agent for ironmaking process, while the phase changing of iron ore during reduction reaction may increase the catalyst activity on reforming process

3.

The porous low grade iron ore played important role in the tar reforming which was indicated by increasing of total gas production significantly especially H2 and CO2. The porous iron ore provided the high surface area for tar decomposition reaction and resulting gas production.

4.

The steam addition into decomposition process over porous low grade ore enhanced gas product and declined carbon formation. The addition of steam increased the amount of H2 and CO2 gases through water gas shift reaction. The excessive increasing of gas production occurred at the decomposition of 800oC such as H2, CO and CH4.


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5.

Based on the results above, the proposed method offered promising process for utilization of low grade iron ore as well as solving the tar material problem during energy generation of solid fuels.


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(2)

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(3)

Paethanom, S. Nakahara, M. Kobayashi, P. Prawisudha, K. Yoshikawa, Performance of tar removal by absorption and adsorption for biomass gasification, Fuel Processing Technology 104 (2012) 144 – 154.

(4)

H. Noichi, A. Uddin, E. Sasoka, Stem reforming of naphthalene as model biomass tar over iron-alumunium and iron-zirconium oxide catalyst catalysts, Fuel Processing Technology 91 (2010) 1609 – 1616.

(5)

D. Swiereczynski, S. Libs, C. Courson, A. Kiennemanm. Steam reforming of tar from a biomass gasification process over Ni/olivine catalyst using toluene as a model compound, Applied Catalyst B: Environment 74 (2007): 211-222.

(6)

R. Zhang, RB. Brown, A. Suby, K. Cummer. Catalytic destruction of tar in biomass derived producer gas. Energy Conversion and Management 45( 2004): 995–1014.

(7)

P. Lu, Z. Yuan, C. Wu, L. Ma, Y. Chen, N. Tsubaki. Bio-syngas production from biomass catalytic gasification. Energy Conversion and Management 48 (2007): 1132–1139.

(8)

PA. Simell, JO. Hepola, AO. Krause. Effects of gasification gas components on tar and ammonia decomposition over hot gas cleanup catalysts. Fuel 76 (1997): 1117–1127.


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(9)

Yue, X. Wang, X. Ai, J. Yang, L. Li, X. Lu, W. Ding. Catalytic reforming of model tar compounds from hot coke oven gas with low steam/carbon ratio over Ni/MgO-Al2O3 catalysts. Fuel Processing Technology 91 (2010): 1098-1104.

(10) Dou, J. Gao, X. Sha, SW. Baek. Catalytic cracking of tar component from high temperature fuel gas. Applied Thermal Engineering 23 (2003): 2229-2239. (11) M. Asadullah, T. Miyazawa, SI. Ito, K. Kunimori, M. Yamada, K. Tomishige. Gasification of different biomasses in a dual-bed gasifier system combined with novel catalysts with high energy efficiency. Appl Catal A: Gen. 267 (2004): 95–102. (12) MP. Aznar, MA. Caballero, J. Gil, JA. Martin, J. Corella. Commercial steam reforming catalysts to improve biomass gasification with steam-oxygen mixtures: 2. Catalytic tar removal. Ind. Eng. Chem. Res 37(1998): 2668-2680. (13) M. Barati, S. Esfahani, TA. Utigard. Energy recovery from high temperature slags. Energy 36 (2011): 5440–5449. (14) Uddin, H. Tsuda, S. Wu, E. Sasaoka. Catalytic decomposition of biomass tars with iron oxide catalysts. Fuel 87 (2008): 451–459. (15) S. Kudo, K. Sugiyama, K. Norinaga, CI. Li, T. Akiyama, JI. Hayashi. Coproduction of clean syngas and iron from woody biomass and natural goethite ore. Fuel 2011. doi:10.1016/j.fuel.2011.06.074. (16) Kurniawan, K. Abe, T. Nomura, T. Akiyama. Integrated Pyrolysis–Tar Decomposition over Low-Grade Iron Ore for Ironmaking Applications: Effects of Coal–Biomass Fuel Blending. Energy Fuels 32 (2018): 396–405


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(17) RB. Cahyono, AN. Rozhan, N. Yasuda, T. Nomura, S. Hosokai, Y. Kashiwaya, T. Akiyama. Catalytic coal-tar decomposition to enhance reactivity of low-grade iron ore. Fuel Processing Technology 113 (2013): 84-89. (18) RB. Cahyono, N. Yasuda, T. Nomura, T. Akiyama. Optimum temperatures for carbon deposition during integrated coal pyrolysis–tar decomposition over low-grade iron ore for ironmaking applications. Fuel Processing Technology 119 (2014): 272-277. (19) Roine, P. Lamberg, T. Katiranta, J. Salminen, HSC Chemistry 7 Simulation. Outotec,


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FIGURE CAPTIONS Figure 1 Experimental apparatus for steam reforming of tar over porous low grade iron ore. T.C : temperature controller. GC: gas chromatography Figure 2 The change in (a) BET surface area and pore volume (b) XRD patterns of iron ore as a result of dehydration process at different temperature. Figure 3 The equilibrium composition of steam reforming of tar material using HSC simulation software. Figure 4 The effect of porous iron ore as catalyst on the total gas production during steam reforming of tar material. Figure 5 The changing of gas production at different reaction time as an effect of porous ore catalyst during steam reforming of tar. Figure 6 The effect of steam addition on the total gas production during tar reforming over porous low grade ore. Figure 7 The changing of gas prodution at different reaction time as an effect of steam addition during tar reforming over porous low grade iron ore Figure 8 The effect of temperature on the total gas production during steam reforming of tar over porous low grade iron. Figure 9 The changing of gas prodution profile as an effect of temperature during steam reforming of tar over porous low grade iron


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Energy & Fuels

TABLES Table 1 Elemental analysis and major components in the liquid tar as raw material Elemental analysis Elemental

Major component

Mass%

Component

Mol%

Carbon

88.59

Benzene

20.97

Hydrogen

8.56

Naphthalene

12.95

Oxygen

2.16

Phenanthrene

4.71

Nitrogen

0.53

Toluene

4.44

Sulfur

0.16

Antrecene

1.99

Acenaphthylene

1.98

Table 2 The main properties of ore samples Low grade ore Pisolite ore aPS:

PSa [mm]

TFeb [%mass]

CWc [%mass]

SAd [m2/g]

0.95–2

58.22

8.62

23.20

particle size; bTFe: total iron; cCW: combined water; dSA: Brunauer–Emmett–Teller surface area


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Experiment list

Figure 1 Experimental apparatus for steam reforming of tar over porous low grade iron ore. T.C : temperature controller. GC: gas chromatography. ACS Paragon Plus Environment

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1 2 0.1 3 100 BET surface area 4 5 Pore volume 80 6 0.08 7 8 9 60 10 0.06 11 12 40 13 14 0.04 15 20 16 Heating rate: 3K/min 17 Atmosphere: air 18 0 0.02 19 0 100 200 300 400 500 600 20 20 30 o 21 Temperature [ C] 22 23 24 25 26 Figure 2 The change in (a) BET surface area and pore volume (b) XRD patterns 27 process at different temperature. 28 29 30 31 32 33 34 35 36 37 38 ACS Paragon Plus Environment 39 40 41

FeOOH

Fe2O3 500℃ 400℃

Intensity[a.u]

(b)

Pore volume[cm3/g]

BET surface area [m2/g]

(a)

300℃ 200℃ Original 40

50 60 2θ[degree]

70

of iron ore as a result of dehydration

80

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kmol

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File: C:\HSC7\Gibbs\Tar_Steam_v2_complete.OGI

8 C

7 6 5

H2(g) CO(g)

4 3

Fe

2 CH4(g) FeO H2O(g)

1 Fe2O3

CO2(g)

Fe3O4

0 0

200

400

600

800

1000

Temperature 1200 C

Figure 3 The equilibrium composition of steam reforming of tar material using HSC simulation software.


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250

Temperature : 600oC. Ratio of tar/steam : 1 (volume)

200 Gas volume [cm3]

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

Energy & Fuels

Without iron ore as catalyst 150

With iron ore as catalyst

100 50 0 H2

CO CO2 Gas component [-]

C1

Figure 4 The effect of porous iron ore as catalyst on the total gas production during steam reforming of tar material.


Energy & Fuels

: Without ore catalyst (total gas : 39.18 cm3 )

80

Gas composition [%vol]

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

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: With ore catalyst (total gas : 351.87 cm3 )

60

H2 CO

40

CO2

CH4 20

0 4

8

12 16 Reaction time [min]

20

Figure 5 The changing of gas production at different reaction time as an effect of porous ore catalyst during steam reforming of tar.


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Carbon content [%mass] 6.07

250

Gas volume [cm3]

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

Energy & Fuels

4.82

Catalyst : Iron ore. Temp : 600oC Without steam (H2O)

200

With steam (H2O) Without steam

With steam

150 100 50 0 H2

CO CO2 Gas component [-]

C1

Figure 6 The effect of steam addition on the total gas production during tar reforming over porous low grade ore.


Energy & Fuels

: With steam (total gas : 379.06 cm3 )

80


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

Page 24 of 26

: Without steam (total gas : 351.87 cm3 )

60

H2 CO

40

CO2

CH4 20

0 4

8


20

Figure 7 The changing of gas prodution at different reaction time as an effect of steam addition during tar reforming over porous low grade iron ore


Page 25 of 26

Carbon content[%mass] 4.80

4.23

3.99

350

600 degC

300

Gas volume [cm3]

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

Energy & Fuels

700 degC 250

800 degC

600

200

700 800 Temperature [oC]

150 100 50 0 H2

CO

CO2

C1

Gas component [-]

Figure 8 The effect of temperature on the total gas production during steam reforming of tar over porous low grade iron.


Energy & Fuels

100

: 600o C (total gas : 379.06 cm3 ) : 800o C(total gas : 622.92 cm3 )


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

Page 26 of 26

80

H2

60

CO CO2

40

CH4 20 0 4

8


20

Figure 9 The changing of gas prodution profile as an effect of temperature during steam reforming of tar over porous low grade iron


Steam Reforming of Tar Using Low-Grade Iron Ore for Hydrogen

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