Ind. Eng. Chem. Process Des. Dev. 1986, 25, 521-527
521
Catalyst Performance in Continuous Hydrotreating of Rundle Shale Oil Timothy G. Harvey, Trevor W. Matheson,+Kerry C. Pratt," and Mark S. Stanborough' CSIRO Division of Materials Science, Clayton, Victoria, Australia 3 168
The 100-400 OC fraction of Rundle shale oil has been processed over three commercial sulfide hydrotreating catalysts at 400 OC, 13.8-MPa hydrogen pressure, and 1-0-h-l LHSV. Ni-W/SiO,-AI,O, deactivated rapidly, Co-Mo/AI,O, was effective, and Ni-Mo/Al,O, was most effective. The Ni-Mo should allow production of a good substitute crude oil but not singlestep production of finished middledistillate fuels. Hydroprocessing under the above conditions did not alter the boiling range of the oil much, but all the catalysts brought about hydrogenation of diaromatic material, a concomitant increase in hydroaromatics, and some cracking of polyaromatics. All the catalysts except the Ni-W completely deoxygenated phenolic components. Residual nitrogen compounds were
predominantly nonbasiz benzo- and dibenzopyrroles.
Oil shale is a sedimentary rock which occurs as large deposits in many countries including the USA, the USSR, Brazil, China, and Australia (Kirk-Othmer, 1981). In Australia, oil shale represents a major energy resource, and currently estimated tertiary in situ resources are over 20 billion barrels of crude oil (National Energy Advisory Committee, 1980). The Rundle deposit, located on the coastline of central Queensland close to port facilities, power and water supplies, and an established industrial infrastructure, contains in situ resources of 2.65 billion barrels of crude shale oil (Central Pacific Minerals, 1980). The deposit is amenable to open-cut mining techniques and provides oil yields in excess of 100 L/ton. It is therefore an attractive candidate for early development. Shale oil is obtained by pyrolysis of oil shale, during which the organic matter (kerogen) in the oil shale breaks down and is condensed as the raw oil. The raw oil must be upgraded by catalytic hydrotreating in order to provide a suitable refinery feedstock. Compared with typical crude oils, shale oil is more olefinic (Proskuryakov, 1978; Tissot, 1978), reflecting its pyrolytic origin, and has a much higher nitrogen and oxygen content (Crowley et al., 1980; Ford et al., 1981; Hardy et al., 1982; Regtop et al., 1982; Shue and Yen, 1981; Uden et al., 1979; Van meter et al., 1952). Sulfur in the oil poisons the precious metal components of hydrocracking catalysts, while basic nitrogen compounds act as poisons for acid sites in both hydrocracking catalysts and fluid catalytic cracking catalfsts. Additionally, the presence of sulfur and nitrogen will lead to SOz and NO, emissions on combustion, and nitrogen, together with oxygen, causes poor storage stability in the final product (Dineen and Bickel, 1951; Drushel and Sommers, 1966). Thus, shale-derived liquids require almost complete removal of heteroatoms but, unlike coal-liquids, need only a modest addition of hydrogen. Catalytic upgrading consists of the removal by hydrogenolysis of organically bound sulfur, oxygen, and nitrogen as HzS,HzO,and NH3,respectively, leaving hydrocarbons
* Author to whom correspondence should be addressed. 'Present address: Coal Research Association of New Zealand Inc., Wellington, New Zealand. Present address: Australian Newsprint Mills Ltd., Hobart, Australia.
*
0196-4305/86/1125-0521$01.50/0
free from heteroatoms. In addition, saturation of aromatics and olefins and hydrocracking occur, increasing both the hydrogen-to-carbon ratio and the yield of material in the transport fuel boiling range. Existing hydrotreating catalysts are not especially effective for the removal of bound nitrogen, which is much more difficult than sulfur removal (Katzer and Sivasubramanian, 1979), and there is a need for the development of catalysts more suited to the commercial processing of shale oil. In a previous characterization of the polar compounds in Rundle shale oil (Bett et al., 1983),we have shown that the major nitrogen-containingpolar compounds in the light boiling fraction (100-250 "C) were alkyl-substituted pyridines, while substituted quinolines were more abundant in the middle (200-400 "C) and heavy (>400 "C) fractions. Significant quantities of pyrrole derivatives were also identified. Small quantities of anilines and benzoquinolines made up the remainder of the bases. The oxygen-containing compounds were mainly phenolic in nature; alkyl-substituted phenols were the major components, but significant quantities of naphthols and traces of fluorenols were identified. Since the most strongly bound nitrogen in the shale oil is within the aromatic rings of heterocyclic compounds, whilst the most refractory oxygen is in the form of phenols, it would be expected that removal of nitrogen would be more difficult than removal of oxygen. Sulfur removal is easier than either nitrogen or oxygen. Removal of nitrogen and oxygen from nitriles and ketones, respectively, is facile. Hence, under conditions where adequate nitrogen removal is achieved, acceptable levels of oxygen and sulfur in the product can usually be assured. The low aromatic content of this shale oil makes it suitable for the production of middle-distillate fuels (diesel and jet fuel). Shale oils characteristically have high pour points which dictate the use of on-site processing, wax modifiers, or heated transport lines. On-site processing may consist of a medium-severity hydrotreating to produce a substitute crude oil or, alternatively, the direct production of middle distillates. The latter requires extensive heteroatom removal and significant hydrocracking and, with the present catalyst systems, would require a twostage process because the hydrogenation/cracking functions of a conventional precious metal-based hydrocracking catalyst would be poisoned by the high level of nitrogen and sulfur compounds. Clearly, a single-stage process, 0 1986 American Chemical Society
522
Ind. Eng. Chem. Process Des. Dev., Vol. 25, No. 2, 1986
Table I. Some Properties of the Catalysts Employed composition, % wt identification BASF M8-21 BASF M8-10 Harshaw Ni-4301E
COO
NiO 3.0
5.0 6.0
Moo3 15.0 13.5
W03
19.0
support Y-AlzO3 Y-AlzO3 Si02/A1203 sio2-59% wt A12O3-41% wt
form 1.5-mm extrudates 3-mm extrudates 1/12-in.extrudates
pore vol V , cm3 g-' 0.6 0.5 0.37
surface area A , m2g-' 160 220 230
av radius r,O nm 7.5 4.5 3.2
"Estimated from r = 2 V / A .
Table 11. Some Important Properties of the Feed Material elemental anal., % w/w C 85.4 0 0.9 H 11.5 ash 0.2 N 1.1 H/C (atomic) 1.61 S 0.9 chem class anal., approx. 70 w/w alkanes 35 bases 2.0 alkenes 25 nitriles 15 aromatics 10 ketones 10 acids 3.0 trace metals, m m Ni 0.4 cu
