CA1062188A - Method of recovery of oil and bitumen from oil-sands and oil shale - Google Patents

Abstract

ABSTRACT
A method of recovering oil from oil sands, wherein the system is operated without the need of water or in general even of heat, at least in appreciable quantities. The subject method includes providing crushed ore, crushed preferably to particulate size, on a perforate bed or support and then spray-ing the so-crushed oil sands ore with a selected solvent at from 1-100 psi gauge pressure such that an oil-containing solution can be collected beneath such support. Thereafter, the oil is recovered by vaporizing the solvent and thereafter condensing the solvent for re-use. Upon vaporization of the solvent, the oil and lighter fractions remain and can be introduced into a refinery or distillation column for recovering desired fractions from the recovered oil or bitumen and also for producing a separate fraction so that the same can be used as an energy source to supply the necessary heat required as well as power for the mechanical equipment used.

Description

-~i The present invention relates to methods of recovering oil from oil sands and, more particularly, to an improved method : -requiring a minimum of energy and little or no utilization of water.

- 2 - ~

, I , , ;
., .. ~ . .. . ... . .

lOt~

Tar sands or oil sands have unique properties among bituminous ore deposits, in that the hydrocarbon bituminous

3 material contained in oil sands is largely soluble in oil

4 solvents without any application of heat.
In the past, many types of expensive and involved ¦ 6 processes have been devised for processing oil sands to recover 7 oil therefrom. U.S. Patent 2,453,060 utilizes heat, water, steam, and solvents in a slurry-flotation system. The process 9 is expensive and can cause serious environmental problems, leaving polluted water and sand. U.S. Patent 2,596,793 presents 11 an expensive procedure utilizing hot methylene chloride and high - 12 pressures for extracting certain petroleum fractions from shale.
Another system is described in U.S. Patent 3,131,141. Tempera-14 tures are used therein in excess of 100 F. The hot tar sands are contacted with liquified, normally gaseous hydrocarbons such 16 as propane. This is an expensive procedure not easily adaptable 17 to large-scale production. Other patents include 3,509,037, ` 18 3,050,289, 2,453,633, 3,503,868, 1,514,113, 3,392,105, and 19 so forth.
A number of these patents disclose batch processing.
21 An experiment simulating this process indicates an extraction 22 rate of less than 85 percent; further, the wet spent tar sands 23 were dirty, containing both solvent and soluble oil. This is ` 24 costly and is believed to create a serious pollution problem.
Patent 1,514,113 utilizes a closed system wherein oil sands and 26 kerosene are mixed in a cement-mixer type arrangement. It is 27 noted that some solvent remains with the sand, and that such l 28 must or may be blown off with steam. This confirms that the 29 sand is, in fact, contaminated with solvent containing some petroleum. A laboratory experiment was made and asphalt ridge 31 tar sands used. It was noted that less than 91 percent recovery 32 was effected. The batch process in U.S. Patent 3,503,868 was A

1(~ 8 1 investigated which discloses a type of pressure cooking of tar 2 and oil sands. The procedures similar to those described in such patent were used in asphalt ridge tar sands, with one liter of gasoline intermixed with an auto-ignition temperature S of 490 F. The cooker was sealed and heated to 450 F and 6 held at this temperature for one hour; after this time the cooker 7 was instantly vented. The procedure was repeated five times, 8 utilizing the initial charge of ta~ sands but adding one liter of new gasoline each time. After the experiment, the tar sands 10 were analyzed and it was found that the system recovered only 11 27 percent of the oil available from the sands. In addition, 12 the dirty tar sands had to be disposed of. While Patent 13 3,503,868 discloses solely the process for removing kerogen 14 from oil shale, the system obviously is ineffective for sands lS processing.
16 Additionally, prior inventions have required inordi-17 nate amounts of heat for preheating materials, supplying steam 18 or hot water solutions, retorting, and so forth. By the 19 present invention, and particularly by virtue of the choice of the solvents made, little if any heat is needed in accomplish-21 lng the process. However, to accelerate solvent recovery for 22 re-use, it is permissible to use a very small amount of heat 23 to vaporize the solvent from the recovered solution so that the 24 solvent can indeed by re-used for spraying.
In contrast and in complete departure from the above, 26 the subject invention involvçs the supporting on a perforate 27 bed, tray, or conveyor belt a layer of particulous tar sands, 28 and then pressure-spraying a suitable solvent or diluent through 29 such tar sands to collect the oil and entraininq solvent in a bath beneath the perforate bed used. Pressures from 1 psi to 31 100 psi provide a critical range of operating pressures, with 32 15 to 60 psi being recommended. The object in view, in operating ~ 10~
1¦ at such pressures, is to provide a sufficient penetration 21 so that the solvent will intimately intermix with and carry 31 off the oil in a slightly reduced viscous form~ Additionally, 41 it was found that efficiencies increased slightly at higher 51 pressures, tending to confirm that there is, in addition to 61 the chemical action, an action of mechanical impaction by 71 the spray droplets that serve to loosen the oil particles from 81 the sand and permit the solvent to~carry such oil droplets 9¦ through the perforate support into the collecting bath. It 10 ¦ has been shown through experimentation that this solvent impinge-11 ¦ ment upon the oil sands actually mechanically dislodges the 12 ¦ petroleum from the sands as well as dissolving it. Pressures 1 13 above 100 psi render the process considerably less effective 14 since the tar sands are simply blown around and pumping cost 15 ¦ is increased. Nozzle pressure must be greater than 1 psi to t 16 gain the mechanical assist necessary in speeding the dissolving 17 ¦ rate. Optimum spray nozzle pressures is in the range of from 18 1 15 to 60 psi, with up to 100 psi being acceptable. Pressures 19 ¦ above 100 psi simply blow the sands about and would require a 20 closed drum arrangement; but this would not avoid a mixing of 21 ¦ the sands with the spray, requiring some considerable filtering 22¦ or centrifuge process, unneeded in the present invention.
23 ¦ ffle partic ~ r solvents suggested have an unus~ly high pene-24 ¦ trating and extraction power and solvent-reoovery effect, this in addition 25 ¦ to having low boiling points, specific heats, and heats of vaporization.
26 ¦ ~x~gh the use of such particular solvents within the critical pressure 27 ¦ range given, vaporization of the solvent from a reoovered oil-and-solvent 28 ¦ solution can be performed in many regions automatically and under ambient 29 ~ temperature o~ ns of the lo ~ e. Iikewise, subsequent condensation 30 ¦ of the solvent used can be had simply by circulating a ooolant fluid such 31 ¦ as a small quantity of water or other heat exchange liquid. This can be ¦ in a closed system.
I , ~ 106;~
The spraying utilized in the process performa a maxi-2 mum recovery with a minimum of materials. Preferred hydrocarbons 3 utilized as "solvents", namely, methylchloroform, trichloroethylene 4 and perchloroethylene, are remarkably effective by virtue of their S high solvent effect, low boiling point, low specific heat, and 6 low heat of vaporization. Additionally, these chemicals are 7 non-flammable.
8 Accordingly, a principal object of the present ~-9 invention is to provide a new and improved method or process for fl 10 recovering oil from oil sands or "tar sands". t 11 A further object is to provide a bitumen oil recovery 12 process which does not require the use of any appreciable quantity 13 of water.
14 An additional object is to provide an oil recovery pro-15 ess, in connection with oil-sand operations, wherein selected 16 solvents of desired characteristics are used so as to reduce if 17 not eliminate the heat required in performing the process.
18 A further object is to provide a solvent spray process t l9 for treating oil sands to recover oil therefrom with a minimum 20 of expense and with the use of little or no water, if such is 21 desired.
22 The features of the present invention may best be 23 understood by reference to the following description taken in 24 connection with the accompanying drawing in which:
The sole figure is a schematic flow sheet of the 26 ~roces~ indicating the manner in which the process is conducted.
27 The first step in the process is to provide crushed 28 ore, namely, crushed oil sands. The largest sized particles 29 hould all be of the order of less than 1-l/2 inches in diameter 1-30 and, preferably, should be of particulate size a majority of 31 which passes a minus 20 to a minus 40 screen mesh. In general, 32 the finer the mesh and particulate size, the greater the oil 106;~1B~
1 recovery. The particulate size generally preferred will 2 resemble that of conventional granulated table sugar, and it 3 has been found that with this size the solvent spraying to 4 follow is much more effective in washing out the bituminous matter in the ~
6 The so crushed and screened ore is then placed in a A~ 7 thin layer (1/4 inch to 1-1/2 inches) on a screen or other perforate support, such as even a perforate conveyer belt.
9 The size of the holes or perforations in the support will of course be less than, say, at least 90 percent of the oil sands 11 disposed thereover.
12 The next step will be to spray downwardly upon the 1 crushed ore, on such support, with one or more selected 14 solvents, at from 1 to 100 psi. This is preferably performed over a perforated conveyer belt containing a layer of the 16 crushed ore of not greater than 1-1/2 inches thick. Thus, 17 the sprayed solvent impinges on the upper surface of such 18 crushed ore and washes therethrough, and through the belt, to 19 entrain the bituminous matter in the solvent and carry the same to an oil-solvent solution below such conveyer belt.
21 The types of solvent that can be used are identified 22 as follows:
23 Group 1. Chlorinated hydrocarbons:
24 carbon tetrachloride methylchloroform trichloroethylene perchloroethylene - 26 chloroform ' ' 10~

In the entire process of selecting and utilizing solvents, it is eminently preferred that either methylchloroform, 3 trichloroethylene or perchloroethylene of the chlorinated hydro-4 carbon group be used. This is because these chemicals are

5 non-flammable, have a very low boiling point, a low specific

6 neat, a low heat of vaporization, and a high solvent effect.

7 There are other groups, however, that can be employed.

8 Thus, any of the following groups 2, 3 or 4 might be used from which a solvent can be selected:
Group 2 - henzene (benzene series) toluene 1 zylene 12 Group 3 - Aromatic hydrocarbons (containing 1-3 1 chlorine atoms) monochlorobenzene 14 orthodichlorobenzene trichlorobenz~ne Group 4 - Saturated aliphatic hydrocarbons, i.e., 16 the alkane series from:
17 pentane (C5 H12) through 14 carbon atoms, 18 i.e.~ C14 H30-All of the above solvents will work successfully.

20 However, infinitely preferable, for the reasons explained, are thylchloroform, trichloroethylene and perchloroethylene. The 22 pecific heats, heats of vaporization, low boiling points and 23 o forth of these three highly preferred chemicals are given in he standard chemical dictionaries and texts.

Numerous tests have been performed, among which the 26 ollowing are representative:

3 o-~
Ar~ .IJ 1~
.. ~ c~ a)a~
~1 s ~ 4 c~
o X
~) w 6 ~ ~ ~ o o ~ o ~ ~ ~ o ~ ~ a) ~ e au e au ~ a~ e 7 ~ ~ o u c~ u

9 ~
f~ oo ~ o a~ _t x u o ~ o o. . . o .. o o. . o o ~ ~ O o oa~ o o~o~ o oo~ o~ o o P. ~ ~
1 ~;

a~ rl ^A
N U~ U~ tQU1 0 U~ Ul U1 o a) o o 15z s~ o u~ o ~ o ~ oo ~ o o o P~ ~ ,~ ,~ In ~ ~D In ~1 ~D ~ ~1 ~ ~D ~r : 17 18~ 3o a~
~ ~ O U~ o u\ r~ ~ ~
19 O ~ ~ ~ o o ~ o ~ o o N 01 01U~ 01a~ U) _I U~ ~ _101 ~ 01 01 N U~ O O O O U~ O U~ U~
2 2 o ~ ~
Z
~ t~
2 3 :~ ~ P
,...... P~

26 ~::

O O e ~ ~~ ,q O e 2 8 ~ ~ o ~, N
O O ~ ~ ~ O ~ O
~ ~ )~ S S S h O ~1 O
~ ~ ~ O O ~ ~ ~ O ~1 0 ~
., _I ~ ~ s --I o O S S O O O S~ ~ U
3 0 u~ C'~ ~ o o o ~~
~ 1 0 a) 0 ~ s 31 s ~cs~ s Su O e c ~ ,~;, u 1 h ~ --I X X 1 --I ~ ~ ~ 1 O 0~1 a) o s a~ a)o ~ a~o 32 ~: X E~ x ~ o ~ :~

ll 106'~
1 ~here:
2 1) The solvent temperature was ambient and varied 3 between 74 F and 83 F.
4 2) Spray nozzles were obtained from the Spraying Systems 5 Company, Wheaton, Illinois 60187.
6 3) The flow rate given above is in gallons per minute.
7 4) GG and HH Nozzles spray a solid square pattern.
8 The W nozzles spray a f]at pattern. The stainless steel screen 9 used was held stationary under the GG and HH noæzles so that the

10 complete bed of tar sands was contacted by the spraying solvent.

11 After studying the data, it became obvious that the

12 type of nozzle had very little or no effect on the extraction

13 rocess. Nozzle pressure, however, does affect percent extrac-

14 ion since the solvent impingement mechanically dislodges the

15 petroleum as well as dissolves it, permitting the sand to pass

16 with the solvent through the perforate support supporting the

17 sand. In order to insure that there is a high percentage of

18 petroleum extraction and that therefore the spraying solvent con-tact essentially all of the crushed tar or oil sands, it is recom-20 mended that the bed of sand disposed on the perforate supporting 21 bed be not less than 1/8 inch nor more than 3/8 inch thick. Such 22 a sand bed thickness, however, should not be looked upon as a 23 limitation herein, since the be~ may vary somewhat from the range 24 giver, e.g., see page 7.
Solvent flow rate is of some importance since the ratio 26 of solvent to petroleum affects the dissolving rate. From a 27 practical viewpoint the solvent flow rate should be somewhere in 28 the range of one to three gallons per minute per square foot of 29 tar sands for a bed 1/8 inch to 3/8 inch thick.
Accordingly, in the invention the advantage of spraying 31 is that there is a fast removal of oil from the sands, both 32 chemically and by virtue of mechanical impingement and, secondly, 106'~
1 ¦the sands are supported by its perforate bed so that there is an 2 ¦automatic separation of the sten sands from the collected liquid.
3 It is noted that there is no water necessary or present 4 in the recovered oil-solvent solution.
The oil-containing solvent is, of course, in solution 6 form, and, hence, the next step will be to vaporize the solvent 7 contained in the solution. This can be done in an extremely low 8 heat environment, the heat applied being dependent upon the 9 solvent being used. Certain ones of the solvents are vaporized 10 readily at normal ambient temperatures and hence, it is possible 11 that no heat will be necessary whatever for summer desert environ-12 ments.
13 Once the solvent is vaporized and, hence, separated from 14 the solution, then the solvent need only be condensed and re-used 15 in connection with the spray step. Such condensation may be per-16 formed by a simple water-coolant, by way of example, in a closed 17 refrigeration system.
18 The residue of the solution, namely, the oil which has

19 been captured, is then simply fractionated in a refinery or dis-

20 tillation column to recover desired hydrocarbon fractions and

21 also to separate out the heat-producing fraction, namely, the

22 bottoms, or those fractions in the heavier fuel-oil region.

23 That fraction of the recovery which is made available

24 or heat can be actually used to produce heat, as by a burner,

25 or vaporizing the solvent where such is needed, and this

26 epending upon the particular solvent selected. The remainder

27 f that same fraction may be converted, as to energy form, by a

28 team generator and turbine for producing electric power to run

29 onveyer belts, pumps, and perform other useful objects as needed.
It cannot be over-emphasized that the preferred selec-31 ion of either methylchloroform, trichloroethylene, or perchloro-32 thylene as a solvent to be used in the process materially solves . - 11-~(~6'~
1 a number of problems. Thus, not only is there a high extraction 2 recovery of the oil contained within the oil sand, but also the 3 characteristics of low boiling point, low specific heat, and low 4 heat of vaporization insures that neither water nor heat are really 5 necessary in the operation for most locales. Indeed, for environ-ments above 65 F, conceivably no additional heat whatever will 7 be required where the three above-named preferred solvents are 8 used; and tap water or stream water could be used to effect the 9 necessary condensation step. In the case of cold-temperature 10 climates, a very minimum of heat is required to vaporize the 11 solvent from the solution in order to re-use the solvent and 12 recover the oil or bitumen collected. Whether these solvents, 13 especially, are used, then it is highly recommended that the 14 spraying and collection steps be in essentially completely 15 enclosed systems, this to minimize solvent loss through vapori-16 zation to the exterior.
It is noted that by virtue of the spray treatment of 18 the crushed oil sands, in lieu of any solvent tank or batch system, that a continuous throughput is rendered possible and 20 minimizes the mechanical steps that need to be taken to effect 21 oil recovery.
22 While particular embodiments of the invention have 23 been shown and described, it will be obvious to those skilled 24 in the art the various changes and modifications which may be 25 made without departing from the essential features of the present 26 invention and, therefore, the aim in the appended Claims is to 27 cover all such changes and modifications as fall within the 28 true spirit and scope of the invention.

~ 12 -

Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for recovering bitumenous organic matter from tar sands, comprising the steps of supplying a layer of crushed ore having particle sizes less than 1? inches in diameter and containing tar sands on a perforate support, spraying such ore with a bitumen solvent from a class consisting of methylchloroform and chloroform, said spraying step being conducted at a pressure of from 1 to 100 psi to recover bitumen therefrom beneath said perforate support, whereby to form a solvent-bitumen solution which is essentially free of water, collecting said solution, vaporizing said solvent of said solution to leave a bitumen residue as a usable product, and condensing the so vaporized solvent for re-use in said spraying step.

2. The step of claim 1 wherein there is included the additional step of fractionating said recovered residue to produce usable end products and a heat-producing fuel fraction, and then converting the energy of said fuel fraction to vaporize said solvent.

3. The process of claim 1 wherein there is included the additional step of fractionating said recovered residue to produce usable end products and a heat-producing fuel fraction converting the energy of said fuel fraction to heat, and applying said heat to said solution to vaporize and subsequently condense said solvent of said solution for re-use in said spraying step.

4. The process of claim 1 wherein there is included the additional step of heating said ore prior to spraying thereof.

5. The process of claim 1 wherein, in the step of supplying crushed ore, said ore is crushed such that a majority thereof passes through a minus twenty mesh screen.

6. A process for recovering oil from tar sands com-prising the steps of supplying a perforated-bed supported layer of crushed ore having particle sizes less than 1? inches in diameter and containing tar sands, spraying downwardly onto and through such ore with a bitumen solvent, from a class con-sisting of methylchloroform and chloroform, at from 1 to 10 psi to recover separated bitumen therefrom beneath such ore and perforated bed, to form a solvent-bitumen solution which is essentially free of water, collecting said solution, vaporizing said solvents to leave a bitumen residue as a usable product, and condensing the so vaporized solvent for re-use in said spraying step.