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Chemical structure changes in Cold Lake oil-sand bitumen and catalytic activities during catalytic hydrotreatment
FUEL PROCESSING TECHNOLOGY ELSEVIER
Fuel Processing
Technology
51 (1997) 195-203
Chemical structure changes in Cold Lake oil-sand bitumen and catalytic activities during catalytic hydrotreatment Ryoichi Yoshida a,*, Makoto Miyazawa b, Hidemi Ishiguro Saburo Itoh a, Kensaku Haraguchi a, Hiroshi Nagaishi a, Hideo Narita a, Tadashi Yoshida a, Yosuke Maekawa a, Yukuaki Mitarai ’
b
,
a Hokkaido National Industrial Research Institute, 2-jo I’/-chome, Tsukisamu-Higashi, Toyohira-ku, Sapporo 062, Japan b Nippon Kokan K.K., l-l, Minamiwatarida-rho, Kawasaki-ku, Kawasaki 210, Japan ’ Sumitomo Metal Mining Co., Ltd.,ll-3, Shimbashi 5-chome, Minato-ku, Tokyo 105, Japan Received
11 July 1996; revised 31 March 1997; accepted 31 March 1997
Abstract Chemical structure changes in Cold Lake oil-sand bitumen and catalytic activities of redmud/sulfur and Ni-Mo catalysts during catalytic hydrotreatment are discussed. Particular attention is given to hydrogenation and hydrogenolysis of structural units, and to the removal of heteroatoms. Ni-Mo catalyst at 450°C reaction temperature gives high conversion of oil-sand bitumen to lower boiling fractions improving H/C ratio and extensive removal of heteroatoms. According to the deposition for bitumen demetallization, Keywords:
of metals on the spent catalysts, red-mud/sulfur catalyst is effective removing V and Ni metals. 0 1997 Elsevier Science B.V.
Catalytic hydrotreatment; Oil-sand bitumen; Chemical structure change
1. Introduction Dependence on non-petroleum resources for energy and petrochemical industry feedstocks will likely increase in the near future because of the shortage of petroleum resources. Coal-derived liquids [l], shale oil [2] and oil-sand bitumen are promising
* Corresponding
author. Tel.: + 81-1 l-8578470;
fax: + 81-1 l-8578484;
0378-3820/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SO378-3820(97)00007-6
e-mail: [email protected].
196
R. Yoshida et al./ Fuel Processing Technology 51 (1997) 195-203
resources for long-range alternatives to petroleum. Oil-sand bitumen has similar properties to petroleum and its deposits are widely distributed throughout the world. Consequently, oil-sand bitumen is a good candidate for replacement of petroleum as a worldwide source of transport fuels and chemical feedstocks. The Alberta, Canada oil-sand reservoirs-including the Peace River, Wabasca, Athabasca, and Cold Lake deposits-are the largest known and most important sources of oil-sand bitumen. Four commercial projects for processing bitumen are at work in Alberta, Canada. The main requirement in upgrading oil-sand bitumen is removal of sulfur, nitrogen, metals, and asphaltene. For better understanding of the behavior of oil-sand bitumen during upgrading to improve its performance, studies on the chemical structure of oil-sand bitumen are indispensable [3-71. In the present paper, chemical structure changes in Cold Lake oil-sand bitumen during catalytic hydrotreatment were studied. Metals deposited on the spent catalysts were examined by ICP (inductively-coupled plasma emission spectroscopy) analysis.
2. Experimental Raw Cold Lake oil-sand bitumen (15 g) was hydrotreated in the presence of red-mud/sulfur [8] or American Cyanamid HDS-3 (3.2 wt% NiO-15.4 wt% MoO,/Al,O,) catalysts (1 g> under reaction conditions of 400-450°C lo-120 min, 22-23 MPa of hydrogen, in a 500 ml shaking-type autoclave. Reaction products were separated by Soxhlet extraction into an oil fraction (hexane solubles) and asphaltene fraction (hexane insoluble, toluene solubles). Raw Cold Lake oil-sand bitumen and oil fraction products were characterized by elemental analysis, ‘H-NMR analysis, thin-layer chromatography with flame-ionization detector (TLC/FID) [9], and gas chromatographic distillation (GCD) [lo]. Metals deposited on the spent catalysts were examined by ICP [ 111.
3. Results and discussion
3.1. Product distribution Results of the hydrotreating experiments are shown in Fig. 1. Raw Cold Lake oil-sand bitumen consists of 84.6 wt% oil fraction and 15.4 wt% asphaltene fraction. Oil fraction yield is higher at 400°C than at 450°C. At both reaction temperatures, oil yields with Ni-Mo catalyst are lower than with red-mud/sulfur catalyst. Oil yields decrease with increasing reaction time for both catalysts. At 400°C conversion of the asphaltene fraction with red-mud/sulfur catalyst is remarkably lower than with Ni-Mo catalyst. However, at 450°C this difference becomes small. Ni-Mo catalyst gives nearly complete asphaltene conversion at both 400 and 450°C. The yield of gaseous products increases with increasing reaction temperature and reaction time. Gas yields with Ni-Mo catalyst are higher than with red-mud/sulfur
R. Yoshida et al./ Fuel Processing Technology 51 (1997) 195-203
0
060 Nominal
reaction
time
Temp. P.2) 0:400 A : 450
catalyst red-mud red-mud
60 Nominal
(min)
Fig. 1. Effect of nominal reaction time on product distribution with red-mud/sulfur and Ni-Mo catalysts.
197
and hydrogen
Temp. PC) 0: 400 A : 450
120
reaction
time
(min)
consumption
at 400 and 45O’C
catalyst Ni-Mo Ni-Mo
catalyst. The yield of hydrogen sulfide with Ni-Mo catalyst is higher than with red-mud/sulfur catalyst. This pattern of hydrogen sulfide yields was also observed in the hydrotreating of shale oil [2] and coal-derived liquids [12]. Hydrogen sulfide yields with Ni-Mo catalyst at 400°C are especially high, even higher than the yields of CH,, C,H,, and C,H,. Hydrogen consumption increases with increasing reaction temperature and reaction time. The hydrogen consumption in the presence of Ni-Mo catalyst is higher than with red-mud/sulfur catalyst at each reaction temperature. According to the results described above, red-mud/sulfur and Ni-Mo catalysts show
198
R. Yoshida et al./ Fuel Processing Technology 51 (1997) 195-203
similar catalytic effects for hydrotreatment of Cold Lake oil-sand bitumen; however, Ni-Mo catalyst is more effective regarding the conversion of asphaltene and desulfurization. 3.2. Boiling range distribution by GCD As shown in Fig. 2, red-mud/sulfur catalyst affords decreasing residue (ca. 4OO”CFBP) and hexane insolubles concentrations with increasing reaction temperature and Naphtha Fr.
Red-mud / sulfurcatalyst 4OOC. ISmin
4OOC. 59min
4OOC. 121mln
45OC, IOmin
45OC, 59min
45OC. 116min
Ni-Mo catalyst 4OOC. 14min
4OOC. 60min
4OOC, 122min
45OC. Ilmin
45OC. 60min 45OC, 12Omin I 0
1 20
I 40
I 60
I 90
, 100
Yield(wt%)
Fig. 2. Boiling range distribution method.
of original and produced
oils from Cold Lake oil-sand
bitumen by GCD
R. Yoshida et al. /Fuel
Processing Technology 51 (1997) 195-203
199
reaction time, where PBP means final boiling point. At 4OO”C, naphtha fraction (ca. IBP-200°C) and heavy fraction (ca. 325-400°C) yields are nearly constant at 1.4-1.5 and 25.3-26.5 wt%, respectively, where IBP means initial boiling point. However, the middle fraction (ca. 200-325°C) yield increases with increased reaction time. At 450°C yields of the naphtha fraction and the middle fraction increase, and the yield of the heavy fraction decreases with increasing reaction time. The maximum naphtha-fraction plus middle-fraction yield is 57.8-59.7 wt%. In the presence of Ni-Mo catalyst, most of the hexane insolubles are converted to Asphaltene original
Red-mud / sulfurcatalyst 4OOC, 15mln
4OOC. 59min
4OOC, IPlmin
45OC. IOmin
45OC, 59min
45OC, 118mln
NI-MO catalyst 4OOC, 14mln
4OOC. 6Omin
4OOC. 120min
45OC. Ilmin
45OC, 60min 45OC. 120min I
0
I
20
,
40
1
60
I
80
I
100
Yield(wt%)
Fig. 3. Type analysisof original and produced oils from Cold-Lake oil-sand
bitumen by TLC/ND
method.
R. Yoshida et al. /Fuel
200
Processing Technology 51 (1997) 195-203
lower boiling fractions. The heavy fraction and residue decrease with increasing reaction temperature and reaction time. On the other hand, yields of naphtha and middle fractions increase continually, up to maxima of about 15 wt% for the naphtha fraction, and for the naphtha plus middle fractions, about 66 wt% at 450°C and 120 min. Therefore, Ni-Mo catalyst is more effective for the conversion of oil-sand bitumen to lower boiling fractions than the red-mud/sulfur catalyst. 3.3. Component type analysis by TLC/ FID Results of component type analysis by TLC/FID are shown in Fig. 3. With red-mud/sulfur catalyst, the aromatics and resin fractions are almost constant, independent of reaction conditions. However, the saturate fraction yield at 400°C increases, and at 450°C decreases, with increasing reaction time. Furthermore, the yield of hexane insolubles decreases successively, and the yield of gaseous products increases continually with reaction temperature and time. With Ni-Mo catalyst, most of the hexane insolubles are converted as mentioned above. At 4OO”C,the saturate fraction increases, and the aromatic fraction decreases, with increasing reaction time. At 45O”C, the saturate fraction yield is lower than at 4OO”C,and increases slightly with reaction time. The resin fraction decreases, and the gaseous products increase with reaction time. The decrease in resin fraction with Ni-Mo catalyst indicates that Ni-Mo catalyst is more effective for the removal of heteroatoms than red-mud/sulfur catalyst. The aromatic fraction is higher at 450 than at 400°C due to higher conversion of resin fraction to aromatic fraction, and to less favorable aromatic hydrogenation. Table 1 Elemental
analysis of original and produced oils from Cold Lake oil-sand
Sample
bitumen
Ultimate analysis (wt%, d.f.)
Atomic ratio
C
H
N
0
S (diff)
H/C
Cold Lake of oil-sand bitumen Hexane solubles (84.6 wt%) Hexane insoluble/toluene solubles
83.7 84.1 81.3
11.4 11.8 8.7
0.5 0.4 1.0
1.2 1.0 1.9
4.0 2.7 7.1
1.64 1.69 1.28
4OO”C, 15 min 4OO”C, 59 min 400°C. 121 min
Red-mud/sulfur 82.7 10.7 83.2 11.3 82.4 11.0
catalyst 0.4 0.7 0.5
0.9 0.6 0.7
5.3 4.2 5.4
1.56 1.63 1.60
45O”C, 10 min 45O”C, 59 min 45O”C, 118 min
84.1 86.3 86.4
10.6 10.4 10.0
0.6 0.7 0.5
0.7 0.5 0.6
4.0 2.1 2.5
1.51 1.45 1.38
400°C. 14 min 4OO”C, 60 min 400°C. 122 min
Ni-Mo 82.3 81.7 84.6
catalyst 11.5 11.5 12.3
0.5 0.4 0.4
0.6 0.5 0.4
5.1 5.9 2.3
1.67 1.70 1.74
45O”C, 11 min 450°C. 60 min 450°C. 120 min
85.8 86.2 86.3
11.9 12.2 11.9
0.5 0.5 0.4
0.5 0.4 0.4
1.3 0.7 1.0
1.66 1.70 1.65
R. Yoshida et al. /Fuel
Processing Technology 51 (1997) 195-203
201
3.4. Elemental analysis
As shown in Table 1 for red-mud/sulfur catalyst, hydrogen contents and H/C atomic ratios of oils produced are lower than those of the original oil, because the hexane insolubles convert to oil and hydrogenation of the oil fraction is slow. Also, the sulfur and oxygen contents of the produced oils are seen to decrease after 450°C and 59 min. With Ni-Mo catalyst (Table l), hydrogen contents and H/C atomic ratios of oils produced after 400°C and 122 min are higher than those of the original oil. Sulfur and oxygen contents are also decreased. Accordingly, these are clearly upgrading processes. The removal of nitrogen below 0.4-0.5 wt% level in the original oil is difficult under the reaction conditions used in the present work. Sulfur contents in produced oil were determined by difference, so the analytical errors are somewhat magnified. 3.5. ‘H-NMR analysis Table 2 shows the distribution of hydrogen determined by ’ H-NMR and the structural parameters calculated using the Brown-Ladner method [13] for the original and
Table 2 Hydrogen
distribution
and structural parameters Hydrogen
of original and produced oil from Cold Lake oil-sand
distribution
a
Structural parameter
bitumen
b
Sample
H,
H,
H0
f,
o
H,, /C,
(~,/~f,)+l
Cold Lake oil-sand bitumen Hexane solubles (84.6wt%) Hexane insoluble/toluene solubles (15.4wt%)
0.058 0.057 0.062
0.168 0.165 0.182
0.775 0.778 0.756
0.26 0.20 0.40
0.64 0.63 0.69
1.17 1.27 0.64
5.6 5.7 5.2
400°C. 15 min 4OO”C, 59 min 400DC, 121 min
Red-mud/sulfur 0.055 0.150 0.054 0.152 0.080 0.187
catalyst 0.794 0.793 0.733
0.27 0.23 0.26
0.64 0.64 0.59
0.90 1.07 1.20
6.3 6.2 4.9
450°C. 10 min 450°C 59 min 450°C 118 min
0.060 0.087 0.110
0.165 0.192 0.244
0.775 0.720 0.646
0.29 0.34 0.38
0.63 0.56 0.56
0.85 0.85 0.89
5.7 4.8 3.6
400°C, 14 min 4OO“C, 60 min 400°C. 122 min
Ni-Mo 0.024 0.047 0.034
catalyst 0.113 0.161 0.123
0.863 0.791 0.843
0.18 0.19 0.16
0.76 0.68 0.68
0.92 1.31 1.15
8.6 5.9 7.9
450°C 11 min 450°C 60 min 450°C. 120 min
0.032 0.037 0.039
0.130 0.148 0.166
0.838 0.815 0.795
0.20 0.18 0.20
0.70 0.69 0.70
0.89 1.09 1.06
7.4 6.5 5.8
a H,: aromatic hydrogen; H,: hydrogen in saturated groups (I to aromatic rings; H,: hydrogen of paraffinic methylene, methenyl, and naphthenes or methylene groups in position p or further from an aromatic ring. b f,: carbon aromaticity; (T: the measure of the substitution of the aromatic system; H,, /C,: the atomic aromatic hydrogen-to-carbon ratio of the hypothetical unsubstituted aromatic material; (H, /H,)+ 1: a measure of the length of the aliphatic carbon chain.
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R. Yoshida et al./ Fuel Processing Technology 51 (19971 195-203
produced oils. With red-mud/sulfur catalyst, H, and f, are higher, and Z&/C, is lower at 450°C than at 400°C. These results indicate that oil fraction consists of higher f, and smaller H,,/C, (namely larger aromatic ring size) structural units at 450 than at 400°C. At 45O”C, H, and {(H,/H,) + 1) tend to decrease. These results correspond to the increase of gaseous products yields. With Ni-Mo catalyst, the values of H, and f, for the produced oils are lower than those for the original oil. The value H,,/C, has a tendency to increase with increasing reaction time at each reaction temperature. These results suggest that hydrogenation has occurred. The decrease of HO and {(HO/H,) + l} with increasing reaction time at 450°C corresponds to the increase of gaseous products yields by hydrocracking. 3.6. Characterization of spent catalysts by ICP analysis The metal composition of fresh and spent catalysts by ICP analysis is shown in Table 3. Concerning red-mud/sulfur catalyst, the deposition of Cu, V, Cr, and Ni metals on spent catalysts was observed. The amount of V and Cr metals deposited is nearly independent of reaction conditions. On the other hand, the amount of Ni metal deposited increases with time at each reaction temperature. The amount of Cu metal deposited at 450°C is higher than that at 400°C and increases with increasing reaction time. Regarding Ni-Mo catalyst, the deposition of Cu, V and Cr metals was revealed. However, the extent of deposition concerning Cr metal is lower, the V metal is nearly the same, and the Cu metal is somewhat higher than that with red-mud/sulfur catalyst. Metal contents in raw Cold Lake oil-sand bitumen by ICP analysis are V 230 ppm,
Table 3 ICP analysis of metals deposited on spent catalysis Temp. (“0
RT * (min)
catalyst
SiO,
AlA
Fe,O,
(wt%)
400 400 400 450 450 450
15 59 121 10 59 118
red-mud red-mud red-mud red-mud red-mud red-mud red-mud
400 400 400 450 450 450
14 60 122 11 60 120
Ni-Mo Ni-Mo Ni-Mo Ni-MO Ni-Mo Ni-Mo Ni-MO
* Nominal reaction time.
Cu
V
Cr
Ni
MO
(ppm)
12.8 18.3 21.5 18.7 20.8 19.7 20.2
14.3 14.6 15.8 15.6 15.9 15.8 15.1
50.2 24.0 28.9 29.7 26.7 29.5 26.2
14 2638 8456 3111 8003 11834 28 673
844 1743 2324 2382 2494 2570 2322
602 2052 2598 2746 2408 2733 2104
80 1446 2621 5097 2213 4136 6657
-
0.0 6.8 6.4 5.9 6.3 12.7 5.7
69.9 53.4 54.3 49.6 54.4 48.8 57.1
0.0 1.5 1.4 2.1 1.1 1.3 1.8
28 23 125 29 625 4448 10049 17 309 16833
69 1292 1484 1487 1584 1536 1691
19 526 421 638 320 552 513
23 789 15029 8719 15312 12656 15595 9645
96791 64296 60371 60846 66528 65 265 65458
R. Yoshida et al. /Fuel
Processing Technology 51(1997)
195-203
203
Ca 128 ppm, Ni 109 ppm, Na 44.2 ppm, Fe 28 ppm, Zn 14.6 ppm, MO 11.1 ppm, Al 2.3 ppm, Cr 0.8 ppm, Co 0.7 ppm and Cu 0.4 ppm. Deposits of Cr and Cu metals on the spent catalysts probably originated from the stainless steel autoclave and Cu gasket. Accordingly, red-mud/sulfur is considered to be an effective catalyst for oil-sand demetallization, and is particularly effective for removal of V and Ni metals.
4. Conclusions The yield of produced oil at 400°C is higher than at 450°C. At both 400 and 450°C oil yields are lower with Ni-Mo catalyst than with red-mud/sulfur catalyst. However, considering conversion of oil-sand bitumen to lower boiling fractions, improving the H/C ratio, and removal of heteroatoms, the optimum reaction conditions are Ni-Mo catalyst at a reaction temperature of 450°C for the upgrading of oil-sand bitumen. The following metals are deposited on spent catalysts: Cu, V, Cr and Ni. Redmud/sulfur catalyst is the superior catalyst for oil-sand demetallization, especially for removal of V and Ni metals.
References [l] R. Yoshida, T. Yoshida, H. Narita, Y. Maekawa, Fuel 65 (1986) 425. [2] R. Yoshida, M. Miyazawa, T. Yoshida, H. Narita, Y. Maekawa, Fuel 75 (1996) 99. [3] M.R. Gray, P. Jokuty, H. Yeniova, L. Nazarewycz, S.E. Wanke, U. Achia, A. Krzywicki, E.C. Sanford, O.K.Y. Sy, Can. J. Chem. Eng. 69 (1991) 833. 141 O.P. Strausz, E.M. Lown, Fuel Sci. Technol. Int. 9 (1991) 269. [5] T.W. Mojelsky, T.M. Ignasiak, Z. Frakman, D.D. McIntyre, E.M. Lown, D.S. Montgomery, O.P. Strausz, Energy Fuels 6 (1992) 83. [6] E.C. Sanford, Energy Fuels 8 (1994) 1276. 171 E.C. Sanford, Ind. Eng. Chem. Res. 33 (1994) 109. [S] R. Yoshida, Y. Maekawa, T. Ishii, G. Takeya, Fuel 55 (1976) 337. [9] R. Yoshida, M. Miyazawa, T. Yoshida, K. Ishizaki, N. Shinriki, Y. Maekawa, Fuel 65 (1986) 421. [lo] R. Yoshida, S. Hara, S. Ibaragi, H. Narita, M. Sato, Y. Maekawa, Liq. Fuels Technol. 2 (1984) 55. [ill R. Yoshida, H. Narita, S. Ito, Y. Hasegawa, Y. Maekawa, A. Tunashima, J. Fuel Sot. Jpn. 69 (1990) 180. [12] R. Yoshida, S. Hara, T. Yoshida, S. Yokoyama, Y. Nakata, Y. Goto, Y. Maekawa, Liq. Fuels Technol. 1 (1983) 101. [13] R. Yoshida, T. Yoshida, Y. Nakata, Y. Hasegawa, M. Hino, Y. Ikawa, M. Makabe, D.M. Bodily, Fuel Process. Technol. 7 (1983) 161.
Fuel Processing
Technology
51 (1997) 195-203
Chemical structure changes in Cold Lake oil-sand bitumen and catalytic activities during catalytic hydrotreatment Ryoichi Yoshida a,*, Makoto Miyazawa b, Hidemi Ishiguro Saburo Itoh a, Kensaku Haraguchi a, Hiroshi Nagaishi a, Hideo Narita a, Tadashi Yoshida a, Yosuke Maekawa a, Yukuaki Mitarai ’
b
,
a Hokkaido National Industrial Research Institute, 2-jo I’/-chome, Tsukisamu-Higashi, Toyohira-ku, Sapporo 062, Japan b Nippon Kokan K.K., l-l, Minamiwatarida-rho, Kawasaki-ku, Kawasaki 210, Japan ’ Sumitomo Metal Mining Co., Ltd.,ll-3, Shimbashi 5-chome, Minato-ku, Tokyo 105, Japan Received
11 July 1996; revised 31 March 1997; accepted 31 March 1997
Abstract Chemical structure changes in Cold Lake oil-sand bitumen and catalytic activities of redmud/sulfur and Ni-Mo catalysts during catalytic hydrotreatment are discussed. Particular attention is given to hydrogenation and hydrogenolysis of structural units, and to the removal of heteroatoms. Ni-Mo catalyst at 450°C reaction temperature gives high conversion of oil-sand bitumen to lower boiling fractions improving H/C ratio and extensive removal of heteroatoms. According to the deposition for bitumen demetallization, Keywords:
of metals on the spent catalysts, red-mud/sulfur catalyst is effective removing V and Ni metals. 0 1997 Elsevier Science B.V.
Catalytic hydrotreatment; Oil-sand bitumen; Chemical structure change
1. Introduction Dependence on non-petroleum resources for energy and petrochemical industry feedstocks will likely increase in the near future because of the shortage of petroleum resources. Coal-derived liquids [l], shale oil [2] and oil-sand bitumen are promising
* Corresponding
author. Tel.: + 81-1 l-8578470;
fax: + 81-1 l-8578484;
0378-3820/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SO378-3820(97)00007-6
e-mail: [email protected].
196
R. Yoshida et al./ Fuel Processing Technology 51 (1997) 195-203
resources for long-range alternatives to petroleum. Oil-sand bitumen has similar properties to petroleum and its deposits are widely distributed throughout the world. Consequently, oil-sand bitumen is a good candidate for replacement of petroleum as a worldwide source of transport fuels and chemical feedstocks. The Alberta, Canada oil-sand reservoirs-including the Peace River, Wabasca, Athabasca, and Cold Lake deposits-are the largest known and most important sources of oil-sand bitumen. Four commercial projects for processing bitumen are at work in Alberta, Canada. The main requirement in upgrading oil-sand bitumen is removal of sulfur, nitrogen, metals, and asphaltene. For better understanding of the behavior of oil-sand bitumen during upgrading to improve its performance, studies on the chemical structure of oil-sand bitumen are indispensable [3-71. In the present paper, chemical structure changes in Cold Lake oil-sand bitumen during catalytic hydrotreatment were studied. Metals deposited on the spent catalysts were examined by ICP (inductively-coupled plasma emission spectroscopy) analysis.
2. Experimental Raw Cold Lake oil-sand bitumen (15 g) was hydrotreated in the presence of red-mud/sulfur [8] or American Cyanamid HDS-3 (3.2 wt% NiO-15.4 wt% MoO,/Al,O,) catalysts (1 g> under reaction conditions of 400-450°C lo-120 min, 22-23 MPa of hydrogen, in a 500 ml shaking-type autoclave. Reaction products were separated by Soxhlet extraction into an oil fraction (hexane solubles) and asphaltene fraction (hexane insoluble, toluene solubles). Raw Cold Lake oil-sand bitumen and oil fraction products were characterized by elemental analysis, ‘H-NMR analysis, thin-layer chromatography with flame-ionization detector (TLC/FID) [9], and gas chromatographic distillation (GCD) [lo]. Metals deposited on the spent catalysts were examined by ICP [ 111.
3. Results and discussion
3.1. Product distribution Results of the hydrotreating experiments are shown in Fig. 1. Raw Cold Lake oil-sand bitumen consists of 84.6 wt% oil fraction and 15.4 wt% asphaltene fraction. Oil fraction yield is higher at 400°C than at 450°C. At both reaction temperatures, oil yields with Ni-Mo catalyst are lower than with red-mud/sulfur catalyst. Oil yields decrease with increasing reaction time for both catalysts. At 400°C conversion of the asphaltene fraction with red-mud/sulfur catalyst is remarkably lower than with Ni-Mo catalyst. However, at 450°C this difference becomes small. Ni-Mo catalyst gives nearly complete asphaltene conversion at both 400 and 450°C. The yield of gaseous products increases with increasing reaction temperature and reaction time. Gas yields with Ni-Mo catalyst are higher than with red-mud/sulfur
R. Yoshida et al./ Fuel Processing Technology 51 (1997) 195-203
0
060 Nominal
reaction
time
Temp. P.2) 0:400 A : 450
catalyst red-mud red-mud
60 Nominal
(min)
Fig. 1. Effect of nominal reaction time on product distribution with red-mud/sulfur and Ni-Mo catalysts.
197
and hydrogen
Temp. PC) 0: 400 A : 450
120
reaction
time
(min)
consumption
at 400 and 45O’C
catalyst Ni-Mo Ni-Mo
catalyst. The yield of hydrogen sulfide with Ni-Mo catalyst is higher than with red-mud/sulfur catalyst. This pattern of hydrogen sulfide yields was also observed in the hydrotreating of shale oil [2] and coal-derived liquids [12]. Hydrogen sulfide yields with Ni-Mo catalyst at 400°C are especially high, even higher than the yields of CH,, C,H,, and C,H,. Hydrogen consumption increases with increasing reaction temperature and reaction time. The hydrogen consumption in the presence of Ni-Mo catalyst is higher than with red-mud/sulfur catalyst at each reaction temperature. According to the results described above, red-mud/sulfur and Ni-Mo catalysts show
198
R. Yoshida et al./ Fuel Processing Technology 51 (1997) 195-203
similar catalytic effects for hydrotreatment of Cold Lake oil-sand bitumen; however, Ni-Mo catalyst is more effective regarding the conversion of asphaltene and desulfurization. 3.2. Boiling range distribution by GCD As shown in Fig. 2, red-mud/sulfur catalyst affords decreasing residue (ca. 4OO”CFBP) and hexane insolubles concentrations with increasing reaction temperature and Naphtha Fr.
Red-mud / sulfurcatalyst 4OOC. ISmin
4OOC. 59min
4OOC. 121mln
45OC, IOmin
45OC, 59min
45OC. 116min
Ni-Mo catalyst 4OOC. 14min
4OOC. 60min
4OOC, 122min
45OC. Ilmin
45OC. 60min 45OC, 12Omin I 0
1 20
I 40
I 60
I 90
, 100
Yield(wt%)
Fig. 2. Boiling range distribution method.
of original and produced
oils from Cold Lake oil-sand
bitumen by GCD
R. Yoshida et al. /Fuel
Processing Technology 51 (1997) 195-203
199
reaction time, where PBP means final boiling point. At 4OO”C, naphtha fraction (ca. IBP-200°C) and heavy fraction (ca. 325-400°C) yields are nearly constant at 1.4-1.5 and 25.3-26.5 wt%, respectively, where IBP means initial boiling point. However, the middle fraction (ca. 200-325°C) yield increases with increased reaction time. At 450°C yields of the naphtha fraction and the middle fraction increase, and the yield of the heavy fraction decreases with increasing reaction time. The maximum naphtha-fraction plus middle-fraction yield is 57.8-59.7 wt%. In the presence of Ni-Mo catalyst, most of the hexane insolubles are converted to Asphaltene original
Red-mud / sulfurcatalyst 4OOC, 15mln
4OOC. 59min
4OOC, IPlmin
45OC. IOmin
45OC, 59min
45OC, 118mln
NI-MO catalyst 4OOC, 14mln
4OOC. 6Omin
4OOC. 120min
45OC. Ilmin
45OC, 60min 45OC. 120min I
0
I
20
,
40
1
60
I
80
I
100
Yield(wt%)
Fig. 3. Type analysisof original and produced oils from Cold-Lake oil-sand
bitumen by TLC/ND
method.
R. Yoshida et al. /Fuel
200
Processing Technology 51 (1997) 195-203
lower boiling fractions. The heavy fraction and residue decrease with increasing reaction temperature and reaction time. On the other hand, yields of naphtha and middle fractions increase continually, up to maxima of about 15 wt% for the naphtha fraction, and for the naphtha plus middle fractions, about 66 wt% at 450°C and 120 min. Therefore, Ni-Mo catalyst is more effective for the conversion of oil-sand bitumen to lower boiling fractions than the red-mud/sulfur catalyst. 3.3. Component type analysis by TLC/ FID Results of component type analysis by TLC/FID are shown in Fig. 3. With red-mud/sulfur catalyst, the aromatics and resin fractions are almost constant, independent of reaction conditions. However, the saturate fraction yield at 400°C increases, and at 450°C decreases, with increasing reaction time. Furthermore, the yield of hexane insolubles decreases successively, and the yield of gaseous products increases continually with reaction temperature and time. With Ni-Mo catalyst, most of the hexane insolubles are converted as mentioned above. At 4OO”C,the saturate fraction increases, and the aromatic fraction decreases, with increasing reaction time. At 45O”C, the saturate fraction yield is lower than at 4OO”C,and increases slightly with reaction time. The resin fraction decreases, and the gaseous products increase with reaction time. The decrease in resin fraction with Ni-Mo catalyst indicates that Ni-Mo catalyst is more effective for the removal of heteroatoms than red-mud/sulfur catalyst. The aromatic fraction is higher at 450 than at 400°C due to higher conversion of resin fraction to aromatic fraction, and to less favorable aromatic hydrogenation. Table 1 Elemental
analysis of original and produced oils from Cold Lake oil-sand
Sample
bitumen
Ultimate analysis (wt%, d.f.)
Atomic ratio
C
H
N
0
S (diff)
H/C
Cold Lake of oil-sand bitumen Hexane solubles (84.6 wt%) Hexane insoluble/toluene solubles
83.7 84.1 81.3
11.4 11.8 8.7
0.5 0.4 1.0
1.2 1.0 1.9
4.0 2.7 7.1
1.64 1.69 1.28
4OO”C, 15 min 4OO”C, 59 min 400°C. 121 min
Red-mud/sulfur 82.7 10.7 83.2 11.3 82.4 11.0
catalyst 0.4 0.7 0.5
0.9 0.6 0.7
5.3 4.2 5.4
1.56 1.63 1.60
45O”C, 10 min 45O”C, 59 min 45O”C, 118 min
84.1 86.3 86.4
10.6 10.4 10.0
0.6 0.7 0.5
0.7 0.5 0.6
4.0 2.1 2.5
1.51 1.45 1.38
400°C. 14 min 4OO”C, 60 min 400°C. 122 min
Ni-Mo 82.3 81.7 84.6
catalyst 11.5 11.5 12.3
0.5 0.4 0.4
0.6 0.5 0.4
5.1 5.9 2.3
1.67 1.70 1.74
45O”C, 11 min 450°C. 60 min 450°C. 120 min
85.8 86.2 86.3
11.9 12.2 11.9
0.5 0.5 0.4
0.5 0.4 0.4
1.3 0.7 1.0
1.66 1.70 1.65
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3.4. Elemental analysis
As shown in Table 1 for red-mud/sulfur catalyst, hydrogen contents and H/C atomic ratios of oils produced are lower than those of the original oil, because the hexane insolubles convert to oil and hydrogenation of the oil fraction is slow. Also, the sulfur and oxygen contents of the produced oils are seen to decrease after 450°C and 59 min. With Ni-Mo catalyst (Table l), hydrogen contents and H/C atomic ratios of oils produced after 400°C and 122 min are higher than those of the original oil. Sulfur and oxygen contents are also decreased. Accordingly, these are clearly upgrading processes. The removal of nitrogen below 0.4-0.5 wt% level in the original oil is difficult under the reaction conditions used in the present work. Sulfur contents in produced oil were determined by difference, so the analytical errors are somewhat magnified. 3.5. ‘H-NMR analysis Table 2 shows the distribution of hydrogen determined by ’ H-NMR and the structural parameters calculated using the Brown-Ladner method [13] for the original and
Table 2 Hydrogen
distribution
and structural parameters Hydrogen
of original and produced oil from Cold Lake oil-sand
distribution
a
Structural parameter
bitumen
b
Sample
H,
H,
H0
f,
o
H,, /C,
(~,/~f,)+l
Cold Lake oil-sand bitumen Hexane solubles (84.6wt%) Hexane insoluble/toluene solubles (15.4wt%)
0.058 0.057 0.062
0.168 0.165 0.182
0.775 0.778 0.756
0.26 0.20 0.40
0.64 0.63 0.69
1.17 1.27 0.64
5.6 5.7 5.2
400°C. 15 min 4OO”C, 59 min 400DC, 121 min
Red-mud/sulfur 0.055 0.150 0.054 0.152 0.080 0.187
catalyst 0.794 0.793 0.733
0.27 0.23 0.26
0.64 0.64 0.59
0.90 1.07 1.20
6.3 6.2 4.9
450°C. 10 min 450°C 59 min 450°C 118 min
0.060 0.087 0.110
0.165 0.192 0.244
0.775 0.720 0.646
0.29 0.34 0.38
0.63 0.56 0.56
0.85 0.85 0.89
5.7 4.8 3.6
400°C, 14 min 4OO“C, 60 min 400°C. 122 min
Ni-Mo 0.024 0.047 0.034
catalyst 0.113 0.161 0.123
0.863 0.791 0.843
0.18 0.19 0.16
0.76 0.68 0.68
0.92 1.31 1.15
8.6 5.9 7.9
450°C 11 min 450°C 60 min 450°C. 120 min
0.032 0.037 0.039
0.130 0.148 0.166
0.838 0.815 0.795
0.20 0.18 0.20
0.70 0.69 0.70
0.89 1.09 1.06
7.4 6.5 5.8
a H,: aromatic hydrogen; H,: hydrogen in saturated groups (I to aromatic rings; H,: hydrogen of paraffinic methylene, methenyl, and naphthenes or methylene groups in position p or further from an aromatic ring. b f,: carbon aromaticity; (T: the measure of the substitution of the aromatic system; H,, /C,: the atomic aromatic hydrogen-to-carbon ratio of the hypothetical unsubstituted aromatic material; (H, /H,)+ 1: a measure of the length of the aliphatic carbon chain.
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produced oils. With red-mud/sulfur catalyst, H, and f, are higher, and Z&/C, is lower at 450°C than at 400°C. These results indicate that oil fraction consists of higher f, and smaller H,,/C, (namely larger aromatic ring size) structural units at 450 than at 400°C. At 45O”C, H, and {(H,/H,) + 1) tend to decrease. These results correspond to the increase of gaseous products yields. With Ni-Mo catalyst, the values of H, and f, for the produced oils are lower than those for the original oil. The value H,,/C, has a tendency to increase with increasing reaction time at each reaction temperature. These results suggest that hydrogenation has occurred. The decrease of HO and {(HO/H,) + l} with increasing reaction time at 450°C corresponds to the increase of gaseous products yields by hydrocracking. 3.6. Characterization of spent catalysts by ICP analysis The metal composition of fresh and spent catalysts by ICP analysis is shown in Table 3. Concerning red-mud/sulfur catalyst, the deposition of Cu, V, Cr, and Ni metals on spent catalysts was observed. The amount of V and Cr metals deposited is nearly independent of reaction conditions. On the other hand, the amount of Ni metal deposited increases with time at each reaction temperature. The amount of Cu metal deposited at 450°C is higher than that at 400°C and increases with increasing reaction time. Regarding Ni-Mo catalyst, the deposition of Cu, V and Cr metals was revealed. However, the extent of deposition concerning Cr metal is lower, the V metal is nearly the same, and the Cu metal is somewhat higher than that with red-mud/sulfur catalyst. Metal contents in raw Cold Lake oil-sand bitumen by ICP analysis are V 230 ppm,
Table 3 ICP analysis of metals deposited on spent catalysis Temp. (“0
RT * (min)
catalyst
SiO,
AlA
Fe,O,
(wt%)
400 400 400 450 450 450
15 59 121 10 59 118
red-mud red-mud red-mud red-mud red-mud red-mud red-mud
400 400 400 450 450 450
14 60 122 11 60 120
Ni-Mo Ni-Mo Ni-Mo Ni-MO Ni-Mo Ni-Mo Ni-MO
* Nominal reaction time.
Cu
V
Cr
Ni
MO
(ppm)
12.8 18.3 21.5 18.7 20.8 19.7 20.2
14.3 14.6 15.8 15.6 15.9 15.8 15.1
50.2 24.0 28.9 29.7 26.7 29.5 26.2
14 2638 8456 3111 8003 11834 28 673
844 1743 2324 2382 2494 2570 2322
602 2052 2598 2746 2408 2733 2104
80 1446 2621 5097 2213 4136 6657
-
0.0 6.8 6.4 5.9 6.3 12.7 5.7
69.9 53.4 54.3 49.6 54.4 48.8 57.1
0.0 1.5 1.4 2.1 1.1 1.3 1.8
28 23 125 29 625 4448 10049 17 309 16833
69 1292 1484 1487 1584 1536 1691
19 526 421 638 320 552 513
23 789 15029 8719 15312 12656 15595 9645
96791 64296 60371 60846 66528 65 265 65458
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Processing Technology 51(1997)
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203
Ca 128 ppm, Ni 109 ppm, Na 44.2 ppm, Fe 28 ppm, Zn 14.6 ppm, MO 11.1 ppm, Al 2.3 ppm, Cr 0.8 ppm, Co 0.7 ppm and Cu 0.4 ppm. Deposits of Cr and Cu metals on the spent catalysts probably originated from the stainless steel autoclave and Cu gasket. Accordingly, red-mud/sulfur is considered to be an effective catalyst for oil-sand demetallization, and is particularly effective for removal of V and Ni metals.
4. Conclusions The yield of produced oil at 400°C is higher than at 450°C. At both 400 and 450°C oil yields are lower with Ni-Mo catalyst than with red-mud/sulfur catalyst. However, considering conversion of oil-sand bitumen to lower boiling fractions, improving the H/C ratio, and removal of heteroatoms, the optimum reaction conditions are Ni-Mo catalyst at a reaction temperature of 450°C for the upgrading of oil-sand bitumen. The following metals are deposited on spent catalysts: Cu, V, Cr and Ni. Redmud/sulfur catalyst is the superior catalyst for oil-sand demetallization, especially for removal of V and Ni metals.
References [l] R. Yoshida, T. Yoshida, H. Narita, Y. Maekawa, Fuel 65 (1986) 425. [2] R. Yoshida, M. Miyazawa, T. Yoshida, H. Narita, Y. Maekawa, Fuel 75 (1996) 99. [3] M.R. Gray, P. Jokuty, H. Yeniova, L. Nazarewycz, S.E. Wanke, U. Achia, A. Krzywicki, E.C. Sanford, O.K.Y. Sy, Can. J. Chem. Eng. 69 (1991) 833. 141 O.P. Strausz, E.M. Lown, Fuel Sci. Technol. Int. 9 (1991) 269. [5] T.W. Mojelsky, T.M. Ignasiak, Z. Frakman, D.D. McIntyre, E.M. Lown, D.S. Montgomery, O.P. Strausz, Energy Fuels 6 (1992) 83. [6] E.C. Sanford, Energy Fuels 8 (1994) 1276. 171 E.C. Sanford, Ind. Eng. Chem. Res. 33 (1994) 109. [S] R. Yoshida, Y. Maekawa, T. Ishii, G. Takeya, Fuel 55 (1976) 337. [9] R. Yoshida, M. Miyazawa, T. Yoshida, K. Ishizaki, N. Shinriki, Y. Maekawa, Fuel 65 (1986) 421. [lo] R. Yoshida, S. Hara, S. Ibaragi, H. Narita, M. Sato, Y. Maekawa, Liq. Fuels Technol. 2 (1984) 55. [ill R. Yoshida, H. Narita, S. Ito, Y. Hasegawa, Y. Maekawa, A. Tunashima, J. Fuel Sot. Jpn. 69 (1990) 180. [12] R. Yoshida, S. Hara, T. Yoshida, S. Yokoyama, Y. Nakata, Y. Goto, Y. Maekawa, Liq. Fuels Technol. 1 (1983) 101. [13] R. Yoshida, T. Yoshida, Y. Nakata, Y. Hasegawa, M. Hino, Y. Ikawa, M. Makabe, D.M. Bodily, Fuel Process. Technol. 7 (1983) 161.