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fluids. The 4 - 6 3 fluid was most desired. Thus a goal was to maximize the 4:6 and 4:2 cSt ratios. The dimer fraction makes a good 2 4 %fluid. The flash and fire points of the trimer fraction are comparable to values obtained from a commercial synthetic 4-cSt fluid. The trimer and bottoms fractions exhibited low pour points and viscosity-temperature characteristics again about the same as a commercial synthetic fluid. The 4and 6-cSt fluids did not exceed the nominal target -40 OF visocosity of 2400 cSt for a 4-cSt fluid or the maximum -40 OF visocosity of 8500 cSt specified for a 6-cSt fluid. The 2.22 ratio of 4:6 cSt fluids made with the BF3-silicawater catalyst was almost the same as the 2.36 ratio obtained with a commercial reference system. In summary, it is concluded that high yields of quality synthetic fluids can be made with this new catalyst system. Conclusions
The BF3-silica-water system has exhibited high potential as a commercially viable catalyst for producing quality synthetic lubricant materials. This catalyst is highly active, gives an attractive product distribution, and also has excellent aging characteristics. Water is a necessary component of the system; in its absence a BF,-silica catalyst rapidly deactivates. BF3water functions as a catalyst, as expected from past reports, but is much less active than the three-component catalyst. BF, can efficiently be removed from the reactor effluent. The recovered BF3 is very pure, with only a minor amount of hydrated BF, present. Since hydrated BF, is a known
catalyst, its presence in recycled BF3 does not present a problem. Thus, BF3 can be recycled to the reactor without additional purification with retained catalytic activity. Besides the cost savings in BF3, a savings can be realized by not having to dispose of a BF3-complexsolution. This catalytic system can produce quality 2-, 4-, and 6-cSt fluids. Acknowledgment
The authors express their appreciation to B. L. Cupples and N. E. Morganson for their advice, to R. Bartek for aiding in the experimental work, and to Gulf Oil Corporation for permission to publish this article. Registry No. 1-Decene,872-05-9; boron trifluoride, 7637-07-2; silica, 7631-86-9.
L i t e r a t u r e Cited Bohlbro, H. (to Esso Research & Engineering Corp.) U.S. Patent 2 728 805, Dec 27, 1955. Brennan, J. A. (to Mobil Oil Corp.) U.S. Patent 3382291, May 7, 1968. Brennan, J. A. (to Mobll Oil Corp.) U S . Patent 3997621, Dec 14, 1976. Child, E. T.; Lafferty, W. L., Jr.; Millendorf, A. J. (to Texaco. Inc.) U.S. Patent 3 109041, Oct 29, 1963. Cotton, F. A.; Wilkinson, G. "Adanced Inorganic Chemistry", 3rd ed.; Interscience: New York, 1972; p 233. Cupples, B. L.; Heilman, W. J. (to Gulf Research & Development Co.) U.S. Patent 4032591, June 28, 1977. Cupples, B. L.; Heilman, W. J.; Kresge, N. (to Gulf Research & Development Co.) (a) U.S. Patent 4045507, Aug 30, 1977; (b) US. Patent 4045508 Aug 30, 1977. Davidson, J. B. (to Sharples Chemicals Inc.) U S . Patent 2 657 245, Oct 27, 1953. Grote, H. W. Oil Gas J . March 31, 1958, 73.
Received for review April 11, 1983 Accepted June 10, 1983
Hydrotreatment of Solvent Refined Coal (SRC) Filtrate and Blending of the SRC Product To Give a Pumpable Fuel Joseph P. Glannettl and Harold E. Swlft" Gulf Research & Development Company, Pittsburgh, Pennsylvania 15230
Mild hydrotreating, i.e., adding about 750 SCF H,/barrel of feedstock, with a commercial residual oil hydrotreating catalyst resulted in a low SRC yield loss, and the SRC product could be easily blended with about onethird its weight of solvent. The resultant product had a desired viscosity of 220 Saybolt Furol Seconds (SFS) at 99 OC which is required for a pumpable fuel. The mild hydrotreatment also resulted in a significant reduction of sulfur content of the SRC; however, the reduction in nitrogen content was not as great.
Introduction
Table I
Solvent Refined Coal (SRC) is produced by dissolving coal with solvent and hydrogen a t about 400-450 "C followed by filtration of the insoluble inorganic ash and removal of the solvent (Bull et al., 1967). Since the inorganic ash has a high sulfur content, the solid deashed coal that results after solvent removal is a much more environmentally acceptable fuel. Further modifications of this process have been made with such objectives as further reducing the sulfur and nitrogen contents of the SRC or converting more of the SRC to liquid and gaseous products (Hinderliter and Perrussel, 1975; Hildebrand et al., 1978). One approach that has been studied involves hydrotreating the SRC filtrate directly after ash removal. Research in this area has been reported by deRosset et al. (1977) and Givens et al. (1978). In the first of these studies an SRC filter feed, having an ash content of about 4 wt
components carbon hydrogen nitrogen oxygen sulfur ash
API a t 71 "C/16"C
feedstock, wt % 89.3
6.3 1.2 2.5 0.7 0.04 -3.0
%, was treated to reduce its ash content to 0.01 wt % followed by hydrotreating. However, in this study details of the catalyst and processing conditions were not given. The government funded research reported by Givens et al. was much more detailed. In this study a SRC filtrate containing about 0.03 wt % ash was hydrorefined with a commercial catalyst.
0196-4321/83/1222-0680$01.50/0 0 1983 American Chemical Society
Ind. Eng. Chem. Prod. Res. Dev., Vol. 22, No. 4, 1983 681
The objective of the research reported in this paper was to evaluate how a pumpable fuel could be made by dissolving SRC in a solvent. A viscosity of 220 SFS at 99 "C is required for a pumpable fuel. Implicit in this objective was to use part of the SRC filtrate as the solvent.
Experimental Section Feedstock. Intermediate coal-solvent slurries were prepared according to the process described in US.Patent 3 341 447 using coal from the Pittsburg & Midway Coal Company's Colonial Mine. The slurry, after filtration for ash removal, produced the feedstock used in this study (Table I). Details of the filtration conditions to obtain this feedstock have been reported elsewhere (Giannetti and Swift, 1980). This feedstock was similar to that reported by deRosset et al. (1977) and Givens et al. (1978). The SRC content of the feedstock was about 33% as compared to 29% reported for the feedstock used by deRosset et al. Catalyst. A commercial residual oil hydrotreating catalyst (0.5 Ni, 1.0 Co, 8.0 Mo on alumina) was used in this study. The catalysts was in the form of 1/32-in.extrudates having surface area, average pore diameter, and pore volume values of 185 m2/g, 188 A, and 0.66 mL/g, respectively. Hydrotreatment. Processing experiments were performed in a downflow fixed-bed automated bench scale pilot unit that could run for extended periods of time. A stainless steel reactor of 1in. internal diameter was charged with 50 g of catalyst diluted with an equal volume of quartz to aid in controlling the exothermic nature of the reaction. ) The catalyst was treated with an H2-H2S(95-5 ~ 0 1 %gas mixture at 343 OC for 4 h prior to contact with the feedstock. The processing was conducted at 427 "C, 1-2 liquid hourly space velocity, 10OOO SCF H2/barrel of feed, and at pressures over the range of 1500-3000 psig. Catalyst performance during the course of the experiments was monitored by measuring the total product liquid OAPI. O A P I is a gravity measurement (hydrometer method ASTM D-287) of the product and is a reasonable measure of catalyst activity, i.e., the amount of hydrogen taken up during reaction. Variations between successive OAPI readings during the course of an experiment indicated the aging performance of the catalyst. Experiments were conducted for about 120 h, during which time catalyst activity appeared to line-out as judged by "API values. The "API measurements were typically made at 71 "C/16 "C as compared to the more common 16 "C/16 "C to make certain that the product would have a positive OAPI value. In addition to the liquid analysis, periodic gas samples were taken; however, since the amount of C1-CI gaseous hydrocarbons was 1% or less based on the feed, these materials are not reported. Product Analysis. The total liquid product was distilled to obtain the naphtha fraction (IBP-191 "C), a socalled wash solvent fraction (191-288 "C), a process solvent fraction (288 OC to a point where the same percentage as in the fresh feed was obtained), and the SRC. Thus, a constant yield of process solvent was obtained even though the end point temperature of this fraction varied. Depending on the feed and the processing severity, the naphtha fraction was about 0.5 wt % of the product, the wash solvent fraction 12-33 wt %, the process solvent 54-55 wt %, with the remainder SRC. The SRC portion was analyzed for viscosity (Saybolt Furol Second, SFS, at 99 "C). Actually, the viscosity at 93 "C was desired, but it did not appear worth the expense of modifying the established test at this point. A great deal of difficulty was encountered in determining the viscosity of the heavier SRC portions, and the results often could
Table 11. Analyses of Liquid and Solid Fractions wt % wash solvent fraction (191-288 "C)
carbon hydrogen nitrogen oxygen sulfur
87.6 8.0 0.7
process solvent fraction (288-454 "C) carbon hydrogen nitrogen oxygen sulfur
90.1 6.5 0.7 1.7
SRC
87.8 5.6 2.0 4.1 0.8
3.4
0.3
1.0
carbon hydrogen nitrogen oxygen sulfur
50
PROCESS SOLVENT
z
0 3
40 -
I-
/
SRC
0
1
1
,
I
/
I
,
,
1
1
I
,
not be duplicated. Viscosities below 300 SFS at 99 OC were reproducible.
Results and Discussions The feedstock was distilled to separate it into the wash and process solvent fractions and the solid SRC for analysis as shown in Table 11. This was done to compare the analyses with corresponding fractions after hydrotreating. Figure 1 shows the wt % product distribution of the three fractions as a function of product OAPI. This relationship was developed by processing at 427 OC, 1-2 LHSV, 10000 SCF H2/barrel of feed, and varying processing pressures between 1500 and 3000 psig. The constancy of the process solvent yield resulted from the distillation procedure described in the Experimental Section. The results show that with increasing total product "API, there was an increased yield of wash solvent at the expense of the SRC. Because the yield of process solvent was kept constant, this resulted in an apparent trade-off of SRC yield for the wash solvent fraction. Table I11 lists sulfur, oxygen, nitrogen, and hydrogen values obtained by analyzing the two liquid fractions and SRC from three of the hydrotreated products. For the 2.8 "API product, there was a decrease in SRC yield over the feed from about 33% to 30%. In comparison with the nonhydrotreated values of Table 11, the sulfur content of the SRC product decreased from 0.8 to 0.11% with the nitrogen content de-
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Ind. Eng. Chem. Prod.
Res. Dev., Vol. 22, No. 4, 1983 600
Table 111. Analyses of Various Fractions Obtained by Hvdrotreatina SRC Filtrate a t Various Severitiesa
500
4 2 7 i "C
300
c
200
b
I
-____-____.
€I N 0 S
H N 0
s
H N 0
s
a
2.8 "API Product (wt %) 8.7 7.3 0.8 0.7 1.1 0.7 < 0.04 0.2
u
6.4
7.0 1.3 0.8 0.11
0.9 0.4
