Energy & Fuels 1992,6, 821-825
82 1
Fluid Catalytic Cracking of Alberta Tar Sand Bitumen Yoshiki Sato,* Yoshitaka Yamamoto, Tohru Kamo, and Keiji Miki Energy Resources Department, National Institute for Resources and Environment, 16-3 Onogawa, Tsukuba City, Ibaraki Prefecture, Japan
Ted Cyr University Programs, Alberta Oil Sands Technology & Research Authority, 500 Highfield Place, 10010-106 Street, Edmonton, Alberta, Canada Received January 16, 1992. Revised Manuscript Received July 21, 1992
Fluid catalytic cracking (FCC) is currently being studied as a method to produce premium value gasoline from petroleum gas oil. In the present investigation, the effect of prehydrotreatment of heavy vacuum gas oil (VGO) of the atmospheric distillation residue (feed material) from Athabasca tar sand bitumen on the yields of light and middle fractions during FCC is reported. Also, the behavior of coke formation during FCC of VGO is examined. Hydrotreatment of feed material was done in a 500-mL autoclave using Ni-Mo/AlzOs catalyst at 390 and 420 "C under an initial hydrogen pressure of 85 kg/cm2(gauge) with a reaction time of 90 min. The FCC of VGO from the hydrotreated and nontreated feed material was done in a small apparatus at 482 "C with WHSV of 16 wt/wt/h under atmospheric pressure of nitrogen. FCC of the VGO from the hydrotreated feed material yielded a drastic increase of naphtha fraction to 43 wt 7% and decreased the heavy fraction to 16 w t 7%. It suggested that, for existing refineries, installation of a mild hydrotreating unit upstream of a FCC may provide an economical increase of yield and quality of useful distillates. The effect of vacuum residue (VR) in the feed material on the reactivity in catalytic cracking was also investigated.
Introduction There are mainly three types of cracking processes in use today.1*2Thermal processes, such as delayed coking or fluid coking, are relatively insensitive to contaminants of heavy materials. The yield of high-value liquid products from this type of processes is not very high since they are not catalytic processes. On the other hand, the catalytic processes are selective to produce high-qualityoil producta at high yields. However, due to the high sensitivity of the hydrocrackingcatalyststo nitrogen and sulfur compounds, they require extremelysevere prehydrotreatments of heavy feed stocksto eliminate contaminants. On the other hand, fluid catalytic cracking requires a moderate severity of prehydrotreatment compared to hydrocracking and provides higher yield of gasoline. Fluid catalytic cracking (FCCI3* is one of the most important processes to produce gasoline of high octane number from petroleum vacuum gas oil (VGO). This process is expected to become even more important due to the change in the feedstock supplies toward heavier petroleum crudes and other alternate resources such as tar sand bitumen, shale oils, or coal liquids. Several types of cracking processes combined with hydrotreatment for the production of premium value gasoline and kerosene (1) deRosset, A. J.; Tan, G.; Hilfman, L. HydrocarbonProcess. 1979, May, 152. (2) Gallagher,J. P.; Humes, W. H.; Siemesen, J. 0. Chem. Eng. Prog. 1979, June, 56. (3) Desai, P. H.; Haseltine, R. P. Oil Cas J. 1989, Oct.23,68. (4) Carter,G. D.; McElhiney, G. HydrocarbonProcess. 1989, Sept., 63. (5) Rhemann, H.; Schwarz, G.; Badgwell, T. A.; Darby, M. L.; White, D. C. Hydrocarbon Process. 1989, June, 64. (6) Vislocky, J. M. Prepr.-Am. Chem. SOC.,Diu. Pet. Chem. 1990, 34(4), 772.
0887-0624/92/2506-0821$03.00/0
from VGO and heavier fractions have been the subject of studies by many investigator~.~>8 Vialock9 reported the effect of feedstock types and the severity of the hydrotreatment on the octane number of the gasoline produced by the fluid catalytic cracking experiments done in a pilot scale. Melin et al." also investigated the properties of gasoline produced by catalytic cracking processes of the hydrotreated cycle oils. The results of those experimental studies emphasize the importance of prehydrotreatments of heavy feedstocks with high aromatic contents. There have also been many basic researchersgJOrelated to the reaction behavior of aromatic compounds in the fluid catalytic cracking process. deRosset et al.' and Gallagher et al.2 studied catalytic cracking of alternate feedstocks such as tar sand bitumen, shale oils, and coal liquids. The reactivities were compared with those of the petroleumoils. They pointed out that prehydrotreatment under high severity was necessary to decrease the heteroatom content, especially of nitrogen, to 500-1OOO ppm for all feedstocks and to increase the hydrogen content of coal liquids to a comparable level (12 w t 7 % ) with the conventional petroleum gas oil. We have already investigated the possibility of applying the FCC process with a prehydrotreatment to coal liquids.11-13 Increasing the severity of the hydrotreatment (7) Melin,M.;Cahen,R.;Bredael,P.;Grootjans,J.Prepr.-Am. Chem. SOC.,Diu. Pet. Chem. 1990, 34(4), 795. (8) Krauee, A. 0. I. Prepr.-Am. Chem. SOC.,Diu. Pet. Chem. 1990, 34(4), 760.
(9) Kriehna, R. Erdoel Kohle, Erdgas, Petrochem. Brenmt. Chem. 1989, 42(5), 194. (10) White, P. J. Oil Cas J. 1968, 66(21), 112. (11) Sato, Y.; Yamanoto, Y.; Kamo,T.; Inaba, A.; Miki, K.Sekiyu Cakkaishi 1990,33(6), 390.
0 1992 American Chemical Society
Sat0 et 01.
822 Energy & Fuels, Vol. 6,No. 6,1992
of the coal-derived middle distillate caused the hydrogenation reactions of aromatic ringa to proceed effectively, but there was no significant difference in distillation properties among the hydrotreated coal liquids. The fluid catalytic cracking of the prehydrotreated coal liquid produced the naphtha fraction with remarkably high yields. It was also found that addition of hydrogendonating compounds to coal liquid increased the yield of lighter products with lesser amount of coke formation. Catalytic cracking of related model compounds has also been carried out to discuss the reactivity of coal liquids. In the present study, the effects of the prehydrotreatment of the atmospheric distillation residue from Athabasca tar sand bitumen (referred as "the feed material") on the yield of the naphtha and the middle fractions have been investigated. The effect of prehydrotreatment on the behavior of coke formation during the subsequentFCC process of the VGO fractionhae been studied. The reaction behavior of the feed material including its vacuum residue (VR)has also been studied for the purpose of identifying the role of VR during upgrading processes.
'
~sabassaBitumen N: 0.42% S:4.74K 0. 1.12%
w
N:0.35%, S2.16% 0 O
'
1.54
W
FCC of hydrotreated prcducto a1 482'6
VGO 3
N ' 0.11% S . 0 71% 0 : 0.87% wc-1.75
N:0.15% S 0.42% 0:1.08% ffil.83
s: 0 36% 0 1.02% coke : 2 1 %
N. 0.05% S: 0 52% 0 0.83% coke : 1.7%
N 0 08%
N : O.W0S : 3.94%0 0.79% wc-1.53
N : 0.87% S : 2.26% 0 0.78%
Experimental Section The feed material used here was the atmospheric distillation residue from Athabasca tar sand bitumen produced by the hot water process. Hydrotreatments of the feed material were carried out in a 500-mL autoclave equipped with a magnetic stirrer at 390 and 420 "C under an initial H2 pressure of 85 kg/cm2 (gauge) over Ni-Mo/Al2Os (Nippon Ketjen, KF-840)extruded catalyst with sulfur. The catalyst-to-feed material ratio and the sulfur-tocatalyst ratio were both 0.1 by weight. The reaction time was 90 min. After hydrotreatment, the products were filtered to separate the catalyst and then distilled under 2 Torr at 330 OC to separate VGO from VR. The experimental scheme is shown in Figure 1. The FCC of the VGO from the hydrotreated and from the nontreated feed material was carried out in a small apparatus, especially designed in conformity with the ASTM standards. The cracking was done at 482 "C under nitrogen atmosphere with a WHSV of 16 wt/wt/h. The ratio of the steamed FCC catalyst-to-feed oil was 3.0 by weight. Shokubaikasei MRZ-206S was used as catalyst. In order to investigate the role of VR during hydrotreatment and FCC processess and the effect on the behavior of coke formation, the catalytic cracking of the whole hydrotreated feed material including VR was also carried out and the results were compared. Experiments were also done at the higher temperatures of 502 and 532 OC. Gaseous producta were analyzed by conventional gas chromatography using Porapack N and molecular sieve 5A, and 13A packed columns. Boiling point distributions of the hydrotreated and the cracked products were measured using the conventional distillation gas chromatographic method. The amount of VR in the cracked product was also analyzed by gas chromatography using phenanthrene as an internal standard. The estimated error of the quantitative analyses of VR was within 10%. Elemental analyses of the hydrotreated and the nontreated feed material and of the cracked products were performed by a CH analyzer for C and H, by a chemiluminescence method for N, by a coulometric titration method for S, and by an oxygen analyzer (Carlo Erba Model HRGC 5300) for 0. The average molecular weight was measured by a vapor pressure osmometer ( W O )using (12) Sato, Y.; Kamo, T.; Yamamoto, Y.; Inaba, A.; Miki, K. Sekiyu Cakkaiehi 1991,34(4), 327. (13) Saw, Y.; Kamo, T.; Yamamoto, Y.; Inaba, A.; Miki, K. Sekiyu Cakkaiehi 1991, 34(4), 335.
Figure 1. Experimental scheme. pyridine as solvent. Details of the experimental apparatus and the procedures have been described previously.ll
Results and Discussion 1. Hydrotreatment of the Feed Material. The feed material was hydrotreated at 390 and 420 "C. Properties of the feed material and the hydrotreated producta are shown in Table I. Both the hydrogen content and the H/C atomic ratio increased from 10.7 to 12.5 wt % and 1.5 to 1.7,respectively, by the hydrotreatmentand the increase was larger at higher hydrotreating temperature. The sulfur content decreased satisfactorily to 0.9 wt 9% at 420 OC. The denitrogenation, however, did not proceed very satisfactorily. The hexane-soluble fraction increased from 87 to almost 100 wt % . The proportion of the VGO also increased significantly from 33.8 to 48.7 and 70.4 wt % , respectively, at 390 and 420 "C. These resulta indicated that hydrotreatment was very effective in increasing the yield of VGO, in lowering the average molecular weight from 480 to approximately360, in decreasing heteroatom content, and in increasing the hydrogen content. The resulta of the elemental analyses for the VGO and the VR before and after the hydrotreatment are separately shown in Table I1 together with the data on the typical petroleum VGO, which we used for comparison. The hydrogen contents and the H/C atomic ratios of VGO increasedfrom 12.Oto 13.4andfrom1.7to 1.8,respectively, by hydrotreatment. On the other hand, the hydrogen contents and the H/C atomic ratios of the corresponding VR did not show any differences. After hydrotreatment, the sulfur content in VGO decreased from 2.7 to 0.4 whereas the nitrogen and the oxygen contents of both VGO and VR did not show big differences within our analytical error limita. As shown in Table I11 and Figure 2, boiling point distribution of the VGO from the hydrotreated feed material at 390 "C (VGO 2) did not show significant differences from that of VGO from the feed material (VGO
Cracking of Alberta Tar Sand Bitumen
Energy & Fuels, Vol. 6,No. 6,1992 823
Table I. Properties of the Nontreated and the Hydrotreated Feed Materials ~
Ca
Ha
No
Sa
0"
H/Catomicratio
ash(&%)
avMW
HS(wt%)
~~
VGO(53E°C-)(wt%)
nontreated 83.16 10.74 0.42 4.74 1.12 1.54 0.54 483.2 87.4 33.8 hydrotreated 85.77 11.97 0.35 2.16 0.66 1.66 366.0 98.1 48.7 Hlb 70.4 H2b 86.63 12.46 0.28 0.92 0.64 1.71 362.0 97.3 a In wt %, daf. b HI: hydrotreatment at 390 "C, 90 min, 85 kg/cm* (gauge) initial Hz pressure. H 2 hydrotreatment at 420 O C , 90 min, 85 kg/cmz (gauge) initial Hz pressure. Table 11. Elemental Analyses (wt W ) of VGO and
C VGO VGO 1 VGO 2 VGO 3
H
N
S
0
VR.
ash atomic ratio H/C
-.
(a)
Gas N a p h t h a fraction
(b)
85.69 12.03 0.15 2.68 0.94 87.28 12.79 0.11 0.71 0.87 87.42 13.38 0.15 0.42 1.08
1.67 1.75 1.83
M i d d o e fraction
I (C)
82.46 84.61 86.40 84.55 85.22
10.21 10.86 10.41 12.69 13.23
0.76 6.76 1.02 0.83 3.94 0.79 0.87 2.26 0.78 0.07 2.46 1.24 0.04 0.11 1.21
1.02
I
1.48 1.53 1.44 1.77 1.85
a VGO 1, VR1: VGO and VR from the nontreated feed material. VGO 2, VR 2: VGO and VR from the hydrotreated feed material (390 O C ) . VGO 3, VR 3 VGO and VR from the hydrotreated feed material (420 O C ) .
Heavy fracton VR-Coae
VR VR1 VR2 VR3 petroleum VGO hydrotreated petroleum VGO
-
-
0
20
I
I
I
40
60
80
Product distribution
1
100 (Wt%)
(a) Hydrotreated leed material (b) Product distribution alter cracking 01 VGO in (b) at 482% (c) Product distribution alter cracking of (a) at 482%
Figure 3. Product distribution of the feed material hydrotreated at 390
600
"C.
-
I
d
(b)
Middle traction
I
!3
I
I
I
0
20
40
I
60
Product distribution
20
40 Fraction
60
80
100-
(%)
VGO from the feed material VGO lrom hydrotreated feed material at 390% VGO from hydrotreated leed material at 420°C Catalytically cracked oil of VGO lrom the leed material Catalylically cracked oil of VGO lrom the hydrotreated leed material at 390% Catalytically cracked oil of VGO from the hydrotreated leed material at 420'C
Figure 2. Boiling point distribution of VGO and their cracked oils.
1). The production of the naphtha fraction (Figure 4)in the VGO from the hydrotreated feed material at higher hydrotreating temperature of 420 "C (VGO3) increased to 16 wt % and the 360 OC+ fraction decreased. The contribution of naphtha fraction to the total hydrotreated feed material was, however, calculated to only 10 wt % as illustrated in Figure 4a. This suggested that hydrotreatment was very effective in decreasing the concentration of heteroatoms of the hydrotreated feed material and in increasing the yield of VGO but was not a satisfactory method for degrading heavy fractions to low molecular weight oils. 2. Catalytic Cracking of VGOs and the Product Distribution. VGO 1 (from the feed material) and VGO 2 and VGO 3 (from the hydrotreated feed material at 390 and 420 OC) have been catalytically cracked to study the effect of prehydrotreatment on the products distribution. The results of the elemental analyses of the cracked oil products from these VGOs are summarized in Table IV. The hydrogen contents and the H/C atomic ratios of the
N a p h t h a tractioi
I
I
80
100
H e a v y traction
(WtX)
(a) Hydrotreated leed material (b) Product distribution after cracking 01 VGO in (b) at 482°C (c) Product distribution alter cracking of (a) at 482°C
Figure 4. Product distribution of the feed material hydrotreatad at 420 O C .
cracked oil products decreased to a level comparable to that of the VGO 1from the nontreated feed material. The results of the gas production, the coke formation during FCC, and the boiling point distribution of VGO are shown in Table 111. The gaseous products consisted mainly of CB(30-40%)) CZand Cr hydrocarbongases, methane, and hydrogen. The gaseous products, especially isobutene, decreased with the severity of the prehydrotreatment. The behavior of coke formation did not show any significant difference by prehydrotreatment. As shown in Table V, the values of fa and RAmeasured by lH NMR for VGO 1, 2, and 3 were considerably low. This is satisfactory considering that the contents of aromatic portion in any VGO,the main cause of the coke formation, were enough low not to make any differences in coke formation. As seen from Table I11and Figure 2,the total distribution of products and the boiling point distribution of the cracked oil products showed significant differences by prehydrotreatment. The concentration of the naphtha fraction (IBP-bp 216 OC) increased as the severity of hydrotreatment from 31 to 43 wt % . The concentration of middle fraction (bp 216-350 "C) showed a small increase, but the concentration of the heavy fraction (bp 350OC+) decreased markedly from 47-72 to 16-29 wt 7%. The extent of conversion of heavy fraction approached 60-72 wt % as shown in the second column of Table VI. However, the
824 Energy & Fuels, Vol. 6, No. 6,1992
Sato et al.
Table 111. Boiling Point Distribution of VGO and Distribution of Their Cracked Products (in wt
%)a
cracked oils
VGO
IBP-216 "C
petroleum VGO hydrotreated petroleum VGO VGO 1 VGO 2 VGO 3
0.9 3.9 15.5
216-350 "C 7.9 8.3 26.9 33.2 37.1
350 "C 92.1 91.7 72.2 62.9 47.4
gas 3.3 2.3 1.9 1.3 1.2
IBP-216 "C 45.4 53.5 31.1 42.5 43.1
216-350 "C 26.9 25.9 35.8 36.7 38.0
350 "C
coke
21.1 16.4 28.8 17.8 15.6
3.3 1.9 2.3 1.7 2.1
VGO 1: VGO from the nontreated feed material. VGO 2: VGO from the hydrotreated feed material (390 "C).VGO 3: VGO from the hydrotreated feed material (420 "C). @
mixing a hydrotreated fraction of bitumen with the feed to a visbreaker or thermal cracker is reported to have an important effect on hydrogen donation and to inhibit coking. Such a fraction produced in the hydrotreated feed material may have a similar effect. 3. Fluid Catalytic Cracking of the Total Feed Material Including VR. The yield of VGO in the hydrotreated feed material increased from 34 to 49% and even to 70% (see Table I) with increasing severity of hydrotreatment. It has also been shown (see Table 1111, that FCC of VGO separately produced oil with a significantly higher yield (43 wt %) of the naphtha fraction. In this section the effect of VR, which represented 3066w t % in both the nontreated and the hydrotreated feed material, on the reactivity during the catalytic cracking process is investigated. The results of the elemental analyses of the catalytically cracked products from the hydrotreated feed material at three different temperatures are shown in Table VII. The hydrogen contents and the H/C atomic ratios in the cracked oil products were almost the same as those of the hydrotreated feed material (see Table I). The nitrogen and oxygen contents decreased somewhat. During FCC, a higher coke formation from the hydrotreated feed material was observed, 12-13 wt 96 at 390 "C and 8-10 wt 5% at 420 OC. The results are shown in Table VIII. However, as seen in Table VIII, the results showed the decrease of VR in the cracked oil products from 50 to 9-16 wt 9% and from 30 to 3-17 wt % by prehydrotreatment at 390 and 420 "C, respectively. Less coke and less VR were produced after FCC for the feed material hydrotreated at severe condition at 420 OC. On the other hand, as seen from Figures 3c and 4c, 34-37 wt 7% of the naphtha fraction was produced from the feed material which originally contained 30-50 wt 9% of VR. This indicates that cracking of VR occurred with accompanying condensation reactions to form coke. In the case of catalytic cracking of VGO only, the contribution of the naphtha fraction wa8 20-30 w t % as seen in Figures 3b and 4b when calculated from the results in Table I11 on
Table IV. Elemental Analyses (wt % ) of Catalytically Cracked Oils from VGO
C
H
N
S
0
H/C atomic ratio
1.07 0.83 1.02 1.05 0.95
1.57 1.64 1.71 1.67 1.75
reactant
VGO 1 VGO 2 VGO 3 petroleum VGO hydrotreated petroleum VGO
87.96 87.98 86.65 86.30 86.87
11.62 0.08 1.97 12.14 0.05 0.52 12.43 0.08 0.36 12.11 1.97 12.76 0.11
concentration of the naphtha fraction in the cracked oil products of VGO from the hydrotreated feed material was 10-20wt % lower than that from petroleum sourcesshown also in Table 111. Similar differences in the conversion of heavy fraction from that of the petroleum sources have been observed, and they are shown in Table VI. In Table VI, the effect of adding a hydrogen donor (tetralin) or a hydrogen acceptor (1-methylnaphthalene) to VGOs on FCC reactivity are shown. In each case, the conversion of the 350 "C+ fraction increased by addition of 50 wt % tetralin to the comparable level of 82-89 wt % with that from petroleum VGO. However, addition of 50 wt % 1-methylnaphthalene had little effect on the conversion of the 350"C+ fraction of VGO 1but decreased the conversion of the 350 "C+ fraction in VGO 2 and VGO 3. The effect of tetralin or 1-methylnaphthalene on the catalytic cracking of coal liquids and aromatic and hydroaromatic compounds has already been reported by us,13 The addition of tetralin to coal liquids improved significantly the conversion of the heavy fraction. For model compounds, analogous results were observed and reported earlier. A mixture of phenanthrene with tetralin was cracked to yield hydrogenated phenanthrenes and alkylnaphthalenes. However, a mixture of phenanthrene with 1-methylnaphthaleneprovided almost no conversion when cracked under similar conditions. These results suggest that, in a cracking process, tetralin donates hydrogen to aromatic compounds. The naphthalenes and their homologues are found primarily in the 207-380 "C fraction of bitumen and the petroleum VGO. For example, in hydrogen donor diluent visbreaking (HDDV)process,14
Table V. Structural Parameters of Feed Materials and VGOs*
VGO 1 VGO 2 VGO 3 nontreated hydrotreated H1 H2
H,
Ha
HO
fa
U
Csids
RT
0.08 0.08 0.07 0.07
0.13 0.10 0.11 0.13
0.80
0.23 0.20 0.15 0.29
0.47 0.39 0.44 0.55
7.4 9.2 8.6 7.3
1.9 1.7 1.4 3.9
0.82 0.83 0.80
RA 0.7 0.7 0.7 1.8
RN
1.2 1.0 0.7 2.1
0.06 0.11 0.83 0.22 0.51 8.3 2.5 1.0 1.5 0.09 0.81 0.10 0.22 0.38 9.0 1.9 0.9 1.0 H,: percent of hydrogen attached to aromatic atom. Ha:percent of hydrogen attached to aliphatic atom at the CY position. H,,:percent of hydrogen attached to aliphatic atom beyond the B position. fa: fraction of aromatic carbon per average molecule. u: degree of substitution of the aromatic system. C&: average number of carbon atoms per aliphatic substituent. RT: number of rings per molecule. RA: number of aromatic rings per molecule. RN: number of naphthenic rings per molecule. @
Cracking of Alberta Tar Sand Bitumen
Energy & Fuels, Vol. 6, No. 6, 1992 825
Table VI. Catalytic Cracking of VGO with and without Solvent at 482 OC with WHSV of 16 wt/wt/ha
reactant petroleum VGO hydrotreated petroleum VGO VGO 1 VGO 2 VGO 3 VGO 1 VGO 2 VGO 3 VGO 1 VGO 2 VGO 3
solvent none none
conversion of 350 OC+ fraction (wt %) 77.1 82.1
none none none tetralin tetralin tetralin 1-methylnaphthalene 1-methylnaphthalene 1-methylnaphthalene
60.1 71.7 67.1 82.1 88.9 84.9 58.1 60.9 58.5
a VGO 1: VGO from the nontreated feed material. VGO 2 VGO from the hydrotreated feed material (390 O C ) . VGO 3: VGO from the hydrotreated feed material (420 "C).
Table VII. Elemental Analyses (wt %) of Cracked Products from the Hydrotreated Feed Material
cracking temp ("C) 482 502 532 482 502 532
WHSV (wt/wt/h) C H N S Hydrotreated at 390 OC, 90 min 16 87.44 11.88 0.10 0.82 16 88.32 12.13 0.11 0.78 16 87.50 12.06 0.13 0.90 Hydrotreated at 420 OC, 90 min 16 87.08 12.18 0.11 0.47 16 87.32 12.36 0.10 0.43 16 86.69 12.29 0.12 0.43
0
HIC atomic ratio
0.53 0.84 0.83
1.62 1.64 1.64
0.46 0.82 0.75
1.67 1.69 1.69
the basis of the total feed material. These results showed that FCC of the feed material including VR provided a higher yield of the naphtha and the middle fractions but formedmorecokes,where nitrogen and oxygen compounds were concentrated.
Conclusion Prehydrotreatment and fluid catalytic cracking of atmosphericdistillation residue from Athabasca tar sand (14)Pet. Refiner 1962, 41(1), 45.
Table VILI. Distribution (wt %) of Cracked Products from the Hydrotreated Feed Material
cracking temp WHSV IBP-216 216-350 350 (OC) (wt/wt/h) ges OC OC "C+ Hydrotreated at 390 "C, 90 min 482 16 1.8 37.1 25.5 13.6 502 16 3.0 36.9 22.2 10.6 532 16 3.2 37.4 23.4 13.1 Hydrotreated at 420 OC, 90 min 482 16 2.0 33.8 30.0 14.4 502 16 1.5 35.5 25.7 11.6 532 16 3.0 44.3 29.2 13.0
VR coke 9.3 12.8 15.8 11.6 11.4 11.5 10.2 16.6 3.1
9.6 9.1 7.5
bitumen was experimentally investigated. Prehydrotreatment was very effective in decreasing the heteroatom contents and in increasing the yield of VGO in the hydrotreated feed materials. However, the boiling point distribution of VGO was not changed very much by prehydrotreatments. FCC of VGO from the hydrotreated feed material increased the yield of the naphtha fraction drastically and decreased the heavy fraction. The conversion of the heavy fraction and the yield of the naphtha fraction were, however, 10-20 wt % lower than that from a typical petroleum VGO. Finally, the effect of VR in the feed material on the reactivity in catalytic cracking was investigated. Fluid catalytic cracking of the total feed material including VR to low molecular weight compounds occurred effectively to produce 34-44 wt % of the naphtha fraction. It has been determined that the overall conversion of the feed material to lighter fraction increased by cracking of the whole feed material with prehydrotreatment. But the coke formation from this material during catalytic cracking was higher by 8-13 wt % than that from petroleum VGO. Further investigation and development of the catalyst regeneration and of the coke resistant catalyst are needed in the future. Acknowledgment. We thank Dr. Natsuko Cyr of the Alberta Research Council for helpful discussion. We also for providing the petroleum thank MitsubishiOil Co., La.,
VGO.
