GB2122638A - Two-stage treatment process for shale oil containing shale solids and metals - Google Patents

Abstract

In the treatment of shale oil 1 contaminated with particulate shale solids and metals, such as iron and arsenic, a close-coupled two-stage hydroprocessing of the oil is performed by (a) contacting the contaminated shale oil with hydrogen in a hydrothermal treating zone 5 to form a product 7 which still contains shale solids and metals, and (b) catalytically hydroprocessing the product by passing the product through a hydroprocessing zone 11 with hydrogen gas 9 in upflow relationship to the catalyst of the hydroprocessing zone. <IMAGE>

Description

SPECIFICATION Two-stage treatment process for shale oil containing shale solids and metals This invention relates to methods of treating retorted shale oil contaminated with shale solids and metals and is concerned with a method of removing substantial amounts of metals, such as arsenic and iron, in the presence of shale fines dispersed in the shale oil, followed by catalytic hydroprocessing of the oil.

The presence of finely divided shale particles in retorted shale oil greatly increases the difficulty of ordinary processing since the shale fines are filterable only with great difficulty and tend to clog conventional hydrogenation catalyst beds. Since in some shale retorting processes the solids content of the retorted oil is 10 weight percent or more, the presence of the solids must be considered.

Another unfortunate characteristic of shale oil is its contamination with metals such as arsenic, selenium, antimony, nickel, vanadium and iron which may interfere with subsequent necessary refining and catalytic processing operations, such as hydrogenation. In many instances contaminants, mainly arsenic and iron, will poison and deactivate the catalysts. It has heretofore been thought highly desirable to reduce these contaminants to very low levels in the shale oil in a separate demetallation process before catalytic hydroprocessing. By the process of the present invention a separate demetallation process is unnecessary.

In prior art processes it is taught that thermal and hydrothermal treatments of shale oil contaminated with metals and/or shale fines are suitable initial treatments in the presence or absence of catalytically inert solid particles. But it was also taught that it was necessary to remove at least a portion of said shale fines (together with adsorbed metals) and said catalytically inert solid particles (together with adsorbed metals) before catalytic hydroprocessing could be successfully performed in a later stage. In the prior art such separations are performed by physical removal of solids, such as agglomeration by rapid cooling, filtration, adsorption, distillation, etc. Such separations generally occur before or during the thermal or hydrothermal stage, or between the thermal-hydrothermal stage and the catalytic hydroprocessing stage.If a solids separation occurs between the thermal-hydrothermal stage and the catalytic hydroprocessing stage, the stages are said to be loosely coupled. On the other hand, the absence of such a separation (or other physical or chemical treatments of the first stage effluent) provides a two-stage process whose stages are said to be close-coupled. Typical of the prior art processes in which either solids are removed before or during the first stage thermal-hydrothermal treatment, or else the first stage is loosely coupled to later stages of the process, are U.S. Patents 4,188,280; 4,159,241; 4,142,961; 4,141,820 and 4,088,567.

The foregoing references are directed to methods of physical removal of substantial amounts of solids and metals from shale oil before it is catalytically hydroprocessed because the metals are viewed as a catalyst poison and the solids are viewed as particularly adept at clogging catalytic reactors.

Several of the references even teach that thermally treated shale oil is more difficult to hydroprocess.

The present invention deals with the same shale oil contaminants, but yields a shale oil feedstock capable of efficient catalytic hydroprocessing under the conditions of the present invention, without physical removal of either the shale solids or the metals.

According to the present invention, there is provided a close-coupled two-stage treatment process for a shale oil containing shale solids and metals comprising the steps of contacting said shale oil with added hydrogen gas in a hydrothermal treating zone to form a product still containing shale solids and metals, catalytically reacting said product in a catalytic hydroprocessing zone by passing said product through said hydroprocessing zone with hydrogen gas in upflow relationship to the catalyst of said hydroprocessing zone, and collecting the effluent of said hydroprocessing zone.

In an embodiment of this invention, a shale oil feedstock containing finely divided shale solids and dissolved metals is contacted with added hydrogen in a hydrothermal treatment zone at a temperature of from 6500F-8500F (343 0--4540C), and without substantial rapid cooling, the product of said hydrothermal treatment zone is catalytically reacted in a catalytic hydroprocessing zone by passing said product in upflow relationship to the catalyst of the hydroprocessing zone at a temperature of from 6000F-8500F (3 1 50--4540C). In another embodiment of this invention, a shale oil feedstock containing finely divided shale solids and metal compounds is contacted with added hydrogen in a hydrothermal treatment zone at a temperature T1 of from 7500--8500F (4000--4540C), and without rapid cooling, the product of said hydrothermal treatment zone is catalytically reacted in a catalytic hydroprocessing zone at a temperature T2 at least 50CF (1 00C) than said temperature T1.

In a preferred embodiment of this invention the product of said catalytic hydroprocessing zone is subjected to a separation step to produce liquid and/or gaseous hydrocarbon products which are substantially free of shale solids and metals and a residue containing said solids and metals.

The present invention is concerned with a close-coupled two-stage hydroprocess comprising a first stage hydrothermal treatment and a second stage catalytic hydroprocess. The invention is characterized by the close-coupling of the two-stage hydroprocessing, and in a preferred embodiment, by a temperature differential between these stages. By close-coupled stages is meant stages of hydroprocessing without intervening liquid/solid separation, or rapid cooling or heating to induce physical or chemical changes (which may lead to separation or agglomeration). The addition of hydrogen gas is not regarded as such an interstage treatment as would alter the close-coupling of the stages. Preferably, liquid/liquid separations are not performed between close-coupled stages.

By contrast, in looseiy coupled multi-stage hydroprocessing the first stage products are not delivered directly to the second stage, or the products of subsequent stages are not directly delivered to still subsequent stages, but rather, the effluent is filtered, or fractionated, or rapidly cooled to promote agglomeration, or subjected to some other interstage manipulation. The product of the first stage may be unstable because of the production of unstable, reactive species in the first stage, which may condense to form high molecular weight refractory products. In such cases, interstage manipulations can be counterproductive and the effluent of the first stage should be fed directly to the second stage for upgrading and stabilization.Furthermore, it is found that the reduction in product viscosity and changes in chemical composition which result from two stages of hydroprocessing makes it much easier to effect the separation of solids. Prior art processes would seek to separate the solids much earlier.

In a preferred embodiment of the present invention a typical retorted shale oil feedstock containing about 0.1 to 20 weight percent of particulate shale solids and having about 4-100 ppm (and typically more than 10 ppm) arsenic as well as other metals such as iron dissolved therein, is mixed with added hydrogen and the mixture thermally treated at a temperature of from 6500 F to 8500 F (343 0--4540C) and a pressure at least sufficient to maintain substantial amounts of the feedstock in the liquid phase for a time sufficient to cause substantial amounts of said arsenic and iron to deposit on, or with, the particulate shale solids. The product of this hydrothermal treatment comprising shale oil containing particulate shale particles and deposited arsenic and iron, is directly transferred to a catalytic hydroprocessing zone.In the hydroprocessing zone the hydrothermally treated product is made to flow upwardly through a fixed, moving or ebullated bed of catalyst, preferably a fixed bed, with added hydrogen. Preferably, the catalyst comprises metal oxides, such as silica and alumina, with hydrogenation components selected from Groups VI and VIII metals and their compounds. Surprisingly, the shale oil will not clog or poison or deactivate the catalyst to give a short run length.

It is preferred that the product of the hydrothermal treatment be transferred directly to the second stage without rapid cooling, but it is recognized that some cooling may occur in transfer, and in fact, in a more preferred embodiment the catalytic second stage operates at a temperature at least 500F (1 00C) cooler than the first stage. Consequently, by "without rapid cooling" is meant that quantity and rapidity of cooling which would induce the rapid agglomerating of solids and/or induce solids settling or depositing in transfer lines, thereby causing processing difficulty due to an unwanted premature solids separation.The tendency toward agglomeration, deposition, etc. will depend on the origin of the raw shale oil (its chemical composition), as well as its treatment history; consequently, it will be within the skill of practitioners of the hydroprocessing art to select those conditions of time, temperature, pressure and other interstage transfer conditions which, within the scope of this invention, provide the best quality liquid product with the greatest processing ease. A suggested means of maintaining temperature control without rapid cooling and the attendant solids separation is by the controlled interstage addition of hydrogen gas, sometimes called "hydrogen quench gas".

In another embodiment of the present invention a retorted shale oil feedstock containing from 0.1 to 20 weight percent of particulate shale solids and containing from 4-1 00 ppm arsenic as well as other metals such as iron, is mixed with added hydrogen and the mixture is thermally treated at a temperature of from 6500F to 8500F (343-4540C) in contact with an inert solid contact material under pressure at least sufficient to maintain the feedstock in the liquid phase for a time sufficient to cause substantial amounts of said arsenic and iron to deposit on, or with, the particulate shale and contact material. The feedstock enters the reactor in its lower portion and flows upwardly through the packed bed of contact material.The product of the hydrothermal treatment comprising shale oil containing shale particles and deposited arsenic and iron, is directly sent to a catalytic hydroprocessing zone. In the catalytic hydroprocessing zone the hydrothermally treated product is made to flow upwardly through a fixed, moving or ebullated bed of catalyst (preferably a fixed bed) with added hydrogen. Preferably, the catalyst comprises metal oxides, such as silica and alumina, with hydrogenation components selected from Groups VI and VIII metals and their compounds. After catalytic hydroprocessing the product is separated from shale solids and contaminants adsorbed or agglomerated with said shale solids by any separation means, e.g., by filtration or centrifugation.

For a further understanding of the invention reference will now be made, by way of example, to the accompanying drawing which shows a flow diagram of an embodiment of the invention.

In the embodiment illustrated by the flow diagram of the drawing, a shale oil feedstock 1 contaminated with shale fines and metals is mixed with hydrogen gas 3 and recycle gas 17 and is pumped upwardly through the hydrothermal reaction vessel 5 at elevated temperatures. The product 7 of the hydrothermal zone 5, still contaminated with shale solids and metals, is (optionally) mixed with additional amounts of added hydrogen 9 prior to or within the catalytic hydroprocessing zone 11. The product 7, with or without additional amounts of added hydrogen, flows upwardly through the hydroprocessing reactor(s) relative to the hydroprocessing catalyst. The product 1 3 of the catalytic hydroprocessing is separated in a separation zone 1 5 into at least three streams, a recycle gas stream 1 7 containing hydrogen, a residue stream 1 9 containing shale solids and separated contaminants, and a product liquid stream 21.

The feedstock for this invention is a shale oil derived from oil shale by any process, preferably by a retorting technique. Conventional retorting processes are carried out by destructive distillation of naturally-occurring oil shale at temperatures which usually range from 700 to 1 3000 F (371 OC to 7040C). The retorting is carried out on oil shale rubble or crushed oil shale and may be carried out in above ground retorts or below ground (in situ), with the necessary heat being supplied by direct combustion within the retort or indirectly by contacting the oil shale with hot gases or solids such as burned shale.In all these processes the shale oil tends to pick up a substantial amount of particulate shale solids, both burned and unburned particles, and despite efforts to remove same by cyclone separation, the retorted oil will contain about 0.1 to 20 weight percent shale solids, preferably 10 weight percent or less shale solids, which amount is difficult to remove from the raw shale oil by conventional means such as filtration, centrifugation, or settling. The shale particles are normally of from 0.2 to 50 microns in size, but it may be economically necessary to allow larger particles to contaminate the shale oil feedstock. Matter, other than carbon and hydrogen, occurring in shale oil, include the elements, compounds and salts of sulfur, arsenic, oxygen, selenium, antimony, iron, nitrogen, vanadium and nickel, principally depending on the source of the naturally occurring oil shale.

The level of arsenic contamination in retorted shale oil is generally more than 4 ppm by weight, often 8 ppm or more by weight, and frequently from 20 to 100 ppm or more, but usually 10 to 50 ppm. The level of soluble iron contamination is generally at least 10 ppm by weight and may range from 30 to 500 ppm or more by weight, but is usually in the range of 20 to 200 ppm. "Soluble arsenic and iron" or "dissolved arsenic and iron" include any salts and compounds of iron or arsenic which are found in the feedstock. The shale oil feedstock may be a whole shale oil or a fraction thereof, preferably it is a whole raw (untreated) retorted shale oil.The molecular weight of the feedstock generally comprises a relatively high molecular weight material having a 50% boiling point range in the 5500--8000F (2880--4270C) range and a 90% boiling point above 8000F (4270C) and more typically in the range of 8500--10000F (4540--5380C), The shale oil will typically have a gravity in the range of from 100 to 300 API, and typically 150--250 API.

The feedstock, with added hydrogen, is given a thermal treatment or heat soak at a temperature in the range of from 6500to 8500F (343--4540C), preferably from 7500F (4000C) less than 850"F (4540 C), and most preferably at a temperature in excess of 8000F (4270C) under a total pressure sufficient to maintain the feedstock in substantially liquid phase, from 50 to 5000 psig, preferably from 500 to 3000 psig and more preferably from 1000 to 2400 psig, for a time sufficient for substantial amounts of dissolved metals such as iron or arsenic to deposit upon the insoluble shale solids, preferably for from 0.01 to 3 hours, more preferably for 0.01 to 2 hours. (LHSV = 0.5-100.) Hydrogen gas is added to said feedstock prior to and/or during said hydrothermal treatment at the rate of from 200-10,000 SCF/bbl of feedstock, preferably 500 to 5,000 SCF/bbl of feedstock.

The hydrogen gas may be preheated, that is before addition to the feedstock, to maintain the desired temperature of the feedstock during hydrothermal treating and to lessen the need for preheating of the oil. Heating a mixture of shale oil with fines and hydrogen to 6000 F or above may cause arsenic and iron to deposit on the furnace tubes. To avoid this problem the oil should be only partially pre-heated and additional heat needed to reach the thermal treatment temperature supplied by hot hydrogen feed. The hot hydrogen and the cooler shale oil mix in the hydrothermal treatment vessel. The feedstock is preferably pumped into the hydrothermal reactor in upflow direction. This provides full vertical backmixing of the feedstock.

No catalyst is added to the feedstock before or during the hydrothermal treatment, nor is any solid inert contact material necessarily added to the feedstock, or present in the hydrothermal treatment vessel. It is conjectured that the shale solids present in the feedstock act either as catalytic bodies, or as inert solids. As the shale oil is heat-soaked with hydrogen, the substantial amounts of the arsenic and iron in the oil will deposit on or with the shale fines leaving a partially decontaminated liquid which if the solids were separated therefrom would contain as little as 10 ppm or less arsenic and reduced amounts of iron as low as about 25 ppm or less.

In an embodiment of the present invention the hydrothermal treatment or heat soak as heretofore described is carried out while the mixture of oil and hydrogen is in contact with an inert contact material which fills, or partially fills, the hydrothermal treatment vessel. It is preferred that the oil and hydrogen, separately or together, enter the hydrothermal treatment vessel in its lower portion and flow upwardly through the packed bed of contact material. The "Gas Pocket Distributor for an Upflow Reactor" disclosed in our co-pending application 8118041 (Serial No. 2078537) is particularly well suited for application in the present context. In the embodiment using contact materials the preferred contact materials include kieselguhr, diatomaceous earths, alumina, spent or substantially spent (i.e., no longer economically feasible for continued catalytic use) hydrocarbon conversion catalysts. In general, the contact material comprises any suitable solid which maintains its structural integrity under conditions of the thermal treating step. The contact material will be of any of the sizes and shapes suitable for solid contact material in the present context. Specifically, the particles will not be so small as to pack into a full blocking mass and they will preferably range in size from 1/32" to 3 inches (0.079-7.62 cm) in diameter or length. The solid contact material can have any shape and can be in the form of pellets, spheres, or shaped particles.

It is evident in the practice of the present invention, that while it may be useful to provide inert contact material in the hydrothermal treatment zone, the product of the hydrothermal treatment zone will still contain appreciable shale solids and metal contaminants (dissolved in the liquid and deposited on or with said solids) within the ranges aforesaid, e.g., 0.1-20 weight percent particulate shale solids and 4-100 ppm arsenic, as well as other contaminants.

The catalytic hydroprocessing of the hot effluent of the hydrothermal treatment step comprises a range of hydroprocessing processes and catalysts from mild hydrogenation of olefins and aromatics through hydrocracking, as suitable for the particular feedstock and product desired, and may encompass catalytic hydrodenitrogenation and/or hydrodesulfurization as may be necessary for the product desired, but will preferably encompass hydrodearsenation and hydrodemetallation reactions, which reactions can occur separately or concurrently on one or more catalysts present in the hydroprocessing zone.

Catalytic hydroprocessing will be carried out in fixed bed, moving bed or ebullated bed reactors, preferably in a fixed bed reactor. In the catalytic hydroprocessing zone the product of the hydrothermai treating stage will move in upflow relationship to the catalyst. One or more consecutive or parallel reactors may be used. The catalysts chosen may vary in activity from reactor to reactor or in layers of the same reactor. The problem of obtaining smooth even catalyst contact without plugging and channeling is amplified if the feed stream contains gases, such as hydrogen gas, as well as solids and liquids. An upflow reactor mode gives surprisingly good results under the conditions of the present invention.The "Gas Pocket Distributor for an Upflow Reactor" disclosed in our aforementioned co pending application Serial No. 2078537 is well suited for application in the present context, and it may also be used in the hydrothermal treating stage, to assure good contacting of the hydrogen gas with the liquids and solids in the feedstock and to prevent coking within the vessel.

Upflow catalytic hydroprocessing is carried out with the solids-containing product of thermal treatment under conventional hydroprocessing conditions without, surprisingly, either poisoning or clogging of the reactor catalyst bed which would shorten the run life substantially. Hydroprocessing is conducted at shale oil temperatures of from 600 to 8500F (31 54540C), preferably from 650 to 8000F (3430--4270C) and more preferably from 650 to 7500F (3434000C). Hydroprocessing is conducted at LHSV from 0.2 to 10, preferably from 0.5 to 6, with hydrogen gas added at the rate of 200-10,000 SCF/bbl of chargestock.

It is most preferred that the catalytic hydroprocessing stage be operated at a temperature of 6500 to 7500F (343--4000C). Since it is preferred that the hydrothermal stage be operated at a temperature greater than 7500F (4000 C), it is evident that a temperature difference may exist between stages. The temperature difference arises basically from the desire to extend the run length of the catalytic hydroprocessing stage and the more effective operation of the hydrothermal stage.Consequently, in a most preferred mode of operation, on a typicai shale oil feedstock, if the hydrothermal treating stage operates at a temperature T, of 7500--8500F (400--4540C) the catalytic hydroprocessing stage will preferably operate at a temperature T2 somewhat lower than Tr, specifically, T2 is about 50"F less than T,.

Hydroprocessing catalysts are well known in the art and include catalysts containing a combination of Group VI metal or metals (e.g. chromium, molybdenum, tungsten) with Group VIII metal or metals (e.g. iron, nickel and cobalt) with or without additional metals such as those of Group IV and a carrier material such as silica, alumina, magnesia, or combinations thereof, such as silica-alumina. An example of a suitable catalyst is cobalt-molybdenum on a silica-alumina support.

After catalytic hydroprocessing, the product will typically be of higher API than the feedstock, have reduced nitrogen content, and preferably contain less than 0.2 ppm dissolved arsenic and less than 1 ppm dissolved iron. The solids content of the product will still be substantial but can now be more easily removed by filtration, centrifugation, or settling because of the lower viscosity and changed chemical composition of the product oil relative to the feedstock.

The solids in the product oil will consist of filterable agglomerants of shale solids, metals, carbon and other contaminants. After treatment by the close-coupled hydroprocessing stages of the present invention, the product is subjected to liquid/liquid or liquid/solid separation by any conventional technique. The agglomerants will have particles sizes (depending on the initial size of the shale fines in the feedstock) of from 0.2 microns to 30 microns or larger. Furthermore, the solids are found to be more easily separable, e.g., because of the lower viscosity and changed chemical composition of the hydroprocessed oil.

After removal of the solids content of the hydroprocessed oil, it may be subjected to further catalytic processing of the kind normally experienced by petroleum refinery feedstocks not derived from oil shale, e.g., hydrotreating.

The following Example illustrates the invention.

EXAMPLE A run was made substantially according to the flow diagram shown in the drawing but without the addition of hydrogen quench gas. The feedstock consisted of a raw shale oil obtained by surface retorting of Western U.S. shale. The feedstock contained 1 0 weight percent of shale dust. The inspections of the feedstock are given in Table 1 together with those of the fiitrate obtained from the product of the process after about 280 hours into the run. Table 1 summarizes the results obtained in the improvement of the quality of the oil, the near elimination of arsenic and iron, and the substantial reduction of nitrogen content are evident.

Operating conditions for the close-coupled two-stage hydroprocessing run of the present example are shown in Table 2. The 400 hours of run length which make up this example are those starting with fresh catalyst and using the feedstock of Table 1. The average temperature differential between the stages was 1 250F (520C). The catalyst in the second stage was a commercial hydrogenation catalyst consisting of nickel and molybdenum on alumina. There were no contact materials in the hydrothermal stage of the run.

The product of the catalytic hydroprocessing stage was separated into gaseous and liquidproducts. The liquid product was stripped with nitrogen and filtered. Analysis of the products of filtration are shown in Table 3.

TABLE 1 Product Slurry Feedstock Filtrate Raw Shale Oil 90 wt % Shale Fines 10 wt % Shale Oil APIO Gravity 20.2 36.2 Pour Point, ASTM, OF +85 60 N,wt% 2.1 0.45 As, ppm 33 0.03 Fe, ppm 28 0.206 Asphaltenes, wt % 0.49 Ramsbottom Carbon, wt % 1.8 LV% < 7000F 38 75 Viscosity 400C,cs 61.81 2.7 1000C,cs 7.310 TABLE2 Operating Conditions 400 Hour Run Run Hours 276-288 383 407 LHSV* 0.95 0.98 Total Pressure*, psig 2302 2283 H2 Mean Pressure*, PSIA 2057 1832 Total Gas In*, SCF/B 6696 6853 Recycle Gas, SCF/B 4913 5093 H2 Consumption (Gross) SCF/B 1783 1760 H2 Consumption (Chem) SCF/B 1342 1653 Temp. OF First Stage 830 826 Second Stage (Aver. CatalystT) 700 701 * In each stage.

TABLE 3 Product Inspections Run Hours 276-288 383-407 Liquid Filtrate Gravity, OKAPI 36.2 35.0 Sulfur, ppm 40.0 64.0 Nitrogen, wt % 0.45 0.57 Arsenic, ppm 0.03 0.03 Nickel, ppm 0.068 0.066 Iron, ppm 0.206 0.196 Pour Point, ASTM, OF 60 65 TBP Distillation, OF Start/5% 51/239 94/205 10/30 293/492 322/457 50 547 568 70/90 661/839 686/861 95/99 918 944 Solids Arsenic, ppm 183.0 183.0 Carbon, wt % 7.97 6.82 Ash, wt % 79.0 80.0

Claims (20)

1. A close-coupled two-stage treatment process for a shale oil containing shale solids and metals comprising the steps of contacting said shale oil with added hydrogen gas in a hydrothermal treating zone to form a product containing shale solids and metals, catalytically reacting said product in a catalytic hydroprocessing zone by passing said product through said hydroprocessing zone with hydrogen gas in upflow relationship to the catalyst of said hydroprocessing zone, and collecting the effluent from said hydroprocessing zone.

2. A process according to Claim 1, wherein the shale oil contains more than 10 ppm arsenic and from 0.1-20 weight percent shale solids.

3. A process according to Claim 1 or 2, wherein the shale solids are of a size substantially within the range from 0.2 to 50 microns in size.

4. A process according to Claim 1, 2 or 3, wherein the shale oil in said hydrothermal treating zone is at a temperature in the range from 650 to 8500F (343--4540C).

5. A process according to Claim 1,2 or 3, wherein the shale oil in said hydrothermal treating zone is at a temperature T, in the range from 7500F (4000C) to less than 8500F (4540C), and without rapid cooling, the product of said thermal treatment zone is catalytically reacted in a hydroprocessing zone at a temperature T2 at least 500F (1 00C) less than said temperature T,.

6. A process according to any preceding claim, wherein the total pressure in said hydrothermal treating zone is from 500 to 3000 psig.

7. A process according to Claim 6, wherein the total pressure in the hydrothermal treating zone is from 1000 to 2400 psig.

8. A process according to any preceding claim, wherein hydrogen is added to the shale oil in the hydrothermal treating zone at a rate of 200 to 10,000 SCF/bbl of shale oil.

9. A process according to Claim 8, wherein hydrogen is added to the shale oil in the hydrothermal treating zone at a rate of from 500 to 5,000 SCF/bbl.

10. A process according to any preceding claim, wherein the shale oil resides in the hydrothermal treating zone for a time sufficient for substantial amounts of said metals to deposit upon the shale solids.

11. A process according to any preceding claim, wherein the shale oil resides in the hydrothermal treating zone for from 0.01 to 1 hour.

12. A process according to any preceding claim, wherein the catalytic hydroprocessing is conducted at a shale oil temperature of from 600 to 8500F (31 5-4540C).

13. A process according to any preceding claim, wherein the catalytic hydroprocessing zone contains a catalyst comprising a carrier material containing a Group VI metal and a Group VIII metal.

14. A process according to Claim 13, wherein the catalyst comprises a silica and/or alumina carrier material.

1 5. A process according to Claim 12, wherein the catalytic hydroprocessing is conducted at LHSV of from 0.2 to 10 with hydrogen gas added at the rate of 200-10,000 SCF/bbl of chargestock.

16. A process according to any preceding claim, wherein the hydrothermal treating zone comprises a vessel containing a packed bed of inert contact material.

1 7. A process according to Claim 16, wherein the shale oil passes through said vessel in upflow relationship to the packed bed of contact material.

1 8. A process according to any preceding claim, wherein the product of said hydrothermal treating zone is passed to said catalytic hydroprocessing zone without liquid/liquid separation.

1 9. A treatment process in accordance with Claim 1 substantially as hereinbefore described with reference to the drawing.

20. A treatment process in accordance with Claim 1 substantially as described in the foregoing Example.