Note: Descriptions are shown in the official language in which they were submitted.
s~
1 ¦¦ BACKGRO~D OF THE INVENTION
2 ll This invention relates to a system and method for
3 ¦I recovering hydrocarbon fue~ fLom hydrocarbon fuel bearing ores;
4 ll particularly gasification recovery of oil from oil-bearing shale
Ij particu]arly recovery of oil from oil-bearing shale and coal
6 1l gasification.
7 Ij As the energy situation becomes more and more critical,
8 1l it is important not only to conserve energy, but also -to find
9 ,, every possible means of recovering energy from all sources
l,l available as economically and as efficiently as possibleO In
J1 ,I this regard, it is well-known that oil shales exist in large
12 ¦¦ deposits which can be readily mined and pyrolyzed to produce
J. 3 'll shale oil and that there are large coal reserves; especially
14 1l in tle United States.
ll The term "oil shalei' refers to marlstone, a
.1.6 1l limestone-like carbonaceous rock that can produce oil when
l7 il h~atcd to pyrolysis temperatures of about 800F. - 1,000F.
18 Ij q'he oil precursor in the shale is an organic pol~ner substance
19 1 of high molecular weight referred to as "kerogen". Oil shale
li is Eound ail over the world and in at least 30 states in the
21 ¦1 United States with estimates of the ~nount of oil locked in
22 ¦i those formations running into the trillions of barrels. In
23 1l addition, a larye amount of the oil shale forma-tions in the
24 !1 United States ~7ith 25 to 30 or more gallons of oil per ton of
2S ¦I shale can only be recovered by underground mining techniques~
26 1I Present techniques for producing oil from shale
27 ¦I require large capital investment, pollution control, handling of
28 1ll raw and spent shale, and the need in some cases for large
29 l,¦ amounts of water to cool the hot kerogen vapors from -~he retort
30 Ijl or ki]n and to slurry and compact the spent shale back into -the
31 il deposit.
32 j' In a modification of retorting applicable to
33 1¦ underground mining reEerred to as in si u minlllg, a t;maLl
5'~ ~
1 I portion of the rock is removed and the rest is reduced to small
2 il particles by e~plosives and then the partic]es are burned in
3 ll place. The oil is collected at the bottom of the natural
4 ' retort and pumped to the surface.
S I ~egardless of the sPeCific technique employed, in
6 1¦ order to produce shale oil in large quantities~ enormous
7 11 expenditures are reguired with present state of the art
~ ¦~ techniques. One company estimates that it will have spent
9 ll more than $100,000,000 by the time its first 9,500 barrel a day
,I retort beyins operatiny. Another company indicates that to
~ pxoduce 48,000 barrels o oil a day, it ~ould need a half dozen
12 ¦1 6 story tall retorts, each capable of processing 11,000 tons of
13 jl shale a day. The company officials estimate that it will cost
1~ I $1.3 billion to $1~5 billion for that operation~ Still another
I cc>mpany states that it has spent over $100,000,000 developing
16 l modified in situ technology for use at the shale sites and have
17 been testing underground retorting for a nu~ber of years. The
1~ last three retorts built by this company were big enough for
19 ~ commercial pxoduct and were 160 feet square and almost 300 feet
¦ high. One collapsed. This company states that to scale
21 ¦1 op~rations up to co~nercial production, it would require 40
22 ¦¦ underground in situ retorts to produce the 50,000 barrels a day
23 1I which was set as a goal.
24 ! There are at least six significant contributory
75 1¦ factors to the continuing lack of economic feasibility for
26 1I recovery of shale oil. These are high fixed costs of on-site
27 I construction of the necessary recovery plants (retorts an~ the
28 like), the high carrying cost of the land necessary to sup ort
29 I the larye recovery plants, the uncertainties as to the
¦ technological feasibility or large plants aue to pro`~lerns
31 1 arising from scaling up from small, successful pilot plants,
32 the logistics of handling vast quantities of oaterials, the
11
Il -3- 1
I! `
1 ll high ris) premium on the cost of capital to carry out the
2 ' recovery, and the environmen~al problems. These same factors
3 , llave inhibited and largely prevented co~ercially-successful
4 coal gasification.
5 Il Thus, it can be understood why no one in the last
6 l~ century has produced shale oil in the United States in other
7 l~ than sma]l quantities, even though efforts to effect commercial
~ l, production have been going on since the l9ZO's and particularly
9 li ~:ine the early 1970's. 1 ~
~ ~s previously noted, the grea-test available source
11 ll of richest deposits of shale in t'ne United States requires
12 ll underground mining where it is expectea that the usual mining
13 l techniques such as large room and pillar mining techniques will
~ have to be used~ This necessitates the dual pro~lem of workirlg
;~5 ll ~o recover the shale and, -further recovering the oil from the
16 ij shale.
17 l¦ Another major problem w;.th regard to extracting
~ ker~gen from shale is the problem of disposing of the spent
19 Il ~hale. Ilav.iny been exposed to the high te~peratures in order
l~ to ~xt:ract tle oil, the shale expands in volume by a factor of
~ as much a5 150% and the original area mined cannot accomodate
22 ~1 all of the e~panded spent shale. Attempts to handle the shale
23 I by Leaving them in dumps has not proven satisfactory. Aside
24 1I from the unsightliness of such dumps, there is the problem of j -
lil pollution due to the fact that rains on such dumps can produce
26 I! a highly alkaline run-off~ This necessitates the devel~pment of ¦
27 l¦ containment devices to prevent any such run-offO There is also
~8 ,l the problem of landscaping and revegetation~
29 1I The same problems o~ massive capital expenditure also
ji applies to efforts to make coal gasification a viable commercial ¦
31 real~ty in the United States even though the ~derlying
32 I technology exists.
1., i
SUMMARY OF THE INVENTION
Thus, the presen~ invention relates to a system
for economic extraction of hydrocarbon fuels from
hydrocarbon-fuel bearing rocks; par~icularly oil from
oil-bearing shale and coal gasificationu
According to one aspect of the invention there
i.s provided a system for extraction of a hydrocarbon fuel
~rom a hydrocarbon fuel-bearing ore comprising: (a) means
for mining the ore; (b) a plurality of portative retorts
for processing said ore to produce a hydrocarbon fuel,
(c) means for transporting said mined ore to each of said
rekorts; ~d) means coupled to said transport means for
regulating the amount of ore transpor~ed to a respective
retort, and (e) at least one storage device coupled to
said retort~ for collecting and storing said hydrocarbon
fuel.
The system, at least in preferred forms, cornprises
means for stockpiling the hydrocarbon-fuel bearing rock,
a plurality of portative retorts for processing said rock
to produce a hydrocarbon fuel, means for transporting said
rock from said stockpile to each of said retorts, means
on each of said retorts coupled to said transport means
~or regulating the amount of said rock transported to a
respective retort, and at least one storage device coupled
to said retorts or collecting and storing said hydrocarbon
fuel produced by said retorts.
According to another aspect of the invention
there is provided a method of extracting o.il from oil-
bearing shale comprising the steps of: (a) forming an
underground chamber in a vein of oil-bearing shale, (b)
mining the shale in said vein, (c) conveying said mined
shale to a plurality of portative retorts of a size to fit
in and located in said chamber, (d) processing said shale
in said retorts to produce an oil-bearing fluid, and (e)
moving the retorts in consonance with movement of mining
of said shale.
The application is particularly applicable to
extra~tion of oil from oil shale and coal gasification
and will be particularly described in connection with the
f ormer.
L0 BRIEF DEscRIPTION OF THE DRAWINGS
Numerous other aspects of this invention along
with additional objectives, features, and advantages of
the invention should now become apparent upon a reading
of the following exposition in conjunction with the accom-
pan~ing drawings in which:
FIG. 1 is a schematic representation of the over-
all mining operation;
- 5a -
~'
~ IG. 2 is a general schematic represen-
tation of the shale oil collection operation;
FIG. 3 is a more detailed schematic
representation of an individual retort and
5 its associated inputs and outputs;
FIG. 4 is a cross-sectional schematic
representation of a room and pillar mining
system in accord with the present invention;
and
FIG. 5 is a cross-sectional schematic
representation of a similar room and pillar
mining system in accord with present conventional
practice.
DETAILED DESCRIPTION
The instant invention will be described
in connection with the recovery of oil from
oiJ. shaJ.e and particularly in connection with
underground mining systems, it being understood
tha~/ if desired, they can also be used with
2U respect to surface mining, such as strip mining
techni~ues. A critical feature of the system
of the instant invention is the ability to
utilize proven portative retorts of a si~e
that they can be placed inl and operate in,
25 underground mines of the room and pillar type
and to move as the mining operation moves.
'`2~''
-
3~
This has significant advantages in both under-
ground as well as surface mining which are
described in detail below. As used herein,
the term "portative" means portable or movable
either by means on the uni.t itself, or by means
5 of a vehicle, such as a tractor, without any
extensive disassembl~y, but in all cases portative
shall mean non-permanent.
First, the ability to process the
shale underground is a tremendous advantage
in that it eliminates the need to carry all
o~ the shale to the surface to be retorted
and then have to .return shale back into the
m:ine for disposa].. I'he only disposal problem
with the instant invention in underground mining
is for the volume of spent shale that cannot
be accommodated by the previously mi.ned area.
Thus, the problem of surface containment of
spent shale is, in addition, greatly minimized.
- 6a -
.'`~- '
1 I Secondly, the proble~ of ernissions is made simpler
2 l¦ in that the retorts being placed in the mine and their being
3 1 limited ways in which the gasses can rise therefrom to the
4 I surface, the emissions can be more readily treated to prevent
5 ll pollution. Also, by having the retorts in the mine, the
6 ll natural beauty of the areas where mining occurs is lar~ely
7 ll preserved. In effect, one is a~le to recover the oil without
~ !l any of the emission problems resulting from surface retorting.
9 1I Portability; i.e., mobility, is also of importance in
~I sur~ace mining in that smaller, mobile units make col~nercial
11 , recovery possible by requiring less land, less reclamation,
12 1l market entry by modexation, optimization of materials handling,
13 1¦ and ability to mix different retort systems to obtain a desired
1~ ¦ by-product mix.
¦l In acldition, the portative retorts are of a si~e such
16 1I that they can be produced in a factory and transported as
17 I self-contained units or in a few readily assembleable parts to
18 ¦ the rnining site. This avoids the much larger cost of on-site
;19 I construction required of large retorts in remote mining ~reas~
I The savings in cos-t are substantial.
2L l! Whi le underyround _n _tu mining by the use of
22 ¦I crea-ting a rubble in the ground and then using the rubbleized
z3 ¦¦ formation for a natural retort has been attempted and is not
24 ll successful in that the recoveries are lo~l, and o~ course, a
~ great deal of the oil is lost, it is kno~7n also that with room
26 l and pillar mining techniques, up to as much as 50 or 60% of
27 1I shale is left in pillars and hence oil cannot be recovered
28 ll therefrom. This, of course, results in higher costs and lo~er
29 ¦I production. Ho~ever, with the inst~t process, it is
30 1! contemplated that as certain areas are mined, after movement of
31 I the retorts to another area for continuous recovery oE
32 additional ore, the sectlons serv1ng as plllars can be collapsed
I -7-
l ll and the remaining ma~erial mined by the rubbleized ln situ
2 ¦I techniques discussed above. This minimizes, again, the cost of
3 ¦I the process and the loss in production. Furtherr the spent shale
4 ~ can be used as a structural support to eliminate the problems of
5 ¦1l surface subsidellce or mine collapse as experienced by
6 ll conventional in situ processing.
7 ~l In short, the instant invention unites the economies
3 I! of scale available with larg~ rnining operations and the economies
9 ¦1 of scale in small already pxo~en retorts known to be successful.
l¦ The instant invention unites large mine and crushing operation
with a series of small, proven retorts which have been made
12 Il~ portative and avoids the costs, uncertainties, and
13 ll sub-optimizatlon of scale-up to large size retorts.
More particularly, the retorts c~ be construc-ted in
L5 ¦1 a ~actory and trucked to the site, avoiding on~site construction
16 ¦l and ef~ecting a large reduction in fixed costs; a reduction as
.17 ¦¦ larye as 85~; small retorts have already been tested and found
succ~s~ul; the use of smaller portative retorts reduces the
19 ¦I ne~saxy amount of land needed for economic feasibility;
~0 ¦¦ materials handling by placing the retorts down in the mine is
21 ¦ largely obviated; the en~ironmental aclvantages and cost
22 1 savings are numerous, particularly with underground mining, and
23 by utilizing smaller, proven retorts and the above economies
24 1 associated therewith, there is a much lower cost-of-capital to
!l- effec-t reco~ery of shale oil.
~6 ll FIG. l is a schematic representation of a shale oil
27 ¦ recovery opexation of the present invention ~hich enables
28 1I recovery of the shale oil throuyh a plurality of individual
29 1I retort operational uni-ts7 each of which, if desired, can be
l~ o~nea hy an individual operator thus eliminating the require.ent
31 I that -the entire capital ou-tlay be produced by one company.
32 ¦¦ Fuxther, each of the retorts is portative (mobile) in nature and
1~
il
1 l, can be quickly connected to or disconnected from the system or
2 1! moved as the mining operation is moved.
3 il As can be seen in FIG. 1, the oil-bearing shale is
4 1I removed by a quarrying operation 10 in any well-~hown manner.
1I The quarrying ~pexation may be a strip mining operation or it
6 1l may be an underground mining operation. Both methods are old
7 11 and well-known and the shale produced thereby is placed on a
~ It conveyer belt 12 which carries the shale to a prirnary crusher
9 ~ which has ja~s or other means for reducing the size of the
'~ !1, shale in a well-known manner. The output from crusher 14 is
`11 1 carxied by conveyer belt 12 to a large screen 16 which separates
12 ,l lumps in excess of the maximum allowable size, The screened
~3 !! ~hale is then carried by conveyer belt 12 to secondary crusher
l~ ! 18 where the large pi,eces of shale are further reduced in size~
¦I Tho crushed shale is carried by conve~er belt 12 from secondary
~ cxusher 18 to a small screen 20 which extracts shale which is
17 ~ ss l:han a minimum allowable size. The residue is carried by
conv~yer belt 12 to a radial stacking unit 22. The radial
'1.,~ ¦ s~l:ack~x 22 can be c~ny of the commercially available -types and
~0 I ~ ckpil~s the o,il-bearing shale over a large area covered by
2,l I movelnent of the stacker in a semi-circular pattern~
22 ¦ A plurality of individual reto,rts 24 receive
23 1l! oil bearing shale from stockpile 26 by means of inclividual
24 1¦ conveyer belts 28. Auto~atic feeders 30 in stockpile 26
I constantly supply the oil-bearing shale to conveyer belts 28.
26 ¦ Each retort 24 has an individual control 32 which is
27 I used to adjus-t its speed and hence the feed rate of the
28 ~I conveyer belt 28 coupled to that particular retort 2a~ Thus~ !
2g 1 the c~mount of shale delivered to each retort can be controlled
1 by means of individual manual control 32~ Further, each
31 , individual retort 24 has its own ~onitor 34 which calculates
32 1I the total ,volu~e of raw shale, eithex in linear fee~ or gross
il ~
1 ll weight, ~Jhich is fed to the particular retort and calculates
2 ll the shale fed to that particular retort. Thus, the shale is
3 l delivered in ~uantities as required by the individual retort
4 1 and the amount of such shale delivered is measured. For each
I retort owned by different operators, billing can be made
6 ll accordiny to the a~ount of shale received. The oil-bearing
7 ll shale is fed into the individua1 retort in -the usual manner
~ ll where it is heated to a temperature ~about 800F. - 1~000F.
g I which releases the shale oil. The residue from the burning
¦ shale is removed as an ash and sold or otherwise discarded. The
11 ! shale oil is fed into a collection system and the gaseous waste
~2 ¦ by-products are also coupled to a cleansing system where they
13 ll are precipitatedr filtered and/or detoxified before the final
14 ¦I wastes are released into the free atmosphere. All of the
I individual retorts are shown as couplea into a common collection
16 ¦ system and by-products cleansing system, but it is also within
17 the scope of this invention for each retort to have its own
l~ I pollution control system. It is also conternplated that
~9 d;fferent retorts can be utilized to form hybrid systems that
I can obtain a variety of by-products dependent upon the retort
21 used.
2~ 1 FIG. 2 is a schematic represen-tation of the shale
23 ¦ oil collection operation from the individual retorts. Thus,
24 l as can be seen in FIG. 2, the oil-bearing shale in stockpile
1 26 is coupled by means of individual conveyer belts 28 to the
26 1~ respective retorts 24. Each of the retor-ts 24 is coupled to a
27 ¦I po~er line 36 which provides the electrical power necessary to
28 ! operate the hydraulics, suction blower and gear ~otors. A
29 l¦ conventional meter unit, not sho~m, at each retort ~onitors
1I the total power consum~d by the retort. If owned by different
31 ¦l operators, they can be billea accordingly. I
32 The )ceroyen released b~ the hested shale flows from
I i - 1 0 -
il I
!j
l 1 each retort's individual pro~uct line 38 to a co~non product line
2 1 ~0 ~hich transfers tlle kerogen to a storage tank ~2. As the
3 kerogen enters the individual product line 3~ from a particular
4 I retort, it flows past a volume rnonitor 44 which measllres and
records the quantity of )cerogen produced and contributed by
6 !1 e(lch individual retort. If individually cwned, the individual
7 1l reto:rt opc>rator is paid according to this volume Eigure.
~ 1 I;'urther, the rneter reading from this ~olurne monitor 44 may also
9 ll be used, as necessary, for computing any royalties which may be
1' owed to the land owner and/or lease payments owed to the lan~
~ owner and/or lease pa~nents owed -to the retort lessor.
1.2 1I The gaseous wastes from eàch retort 24 c~n be
`1~3 !1 col~ected in parallel through a gaseous waste line 46 which
lcads to conven-tional environmental cleansing/by-product
1.5 l eY,tr~C i:ic)n hardw~re 48. Here the gaseous wastes are
lÇ l precipitated, iltexed, and/or detoxified before the final
17 1 w.~s1cs~ in the ~orm of carbon dioxide and ~ater~ are released
l~3 int~ the ~r~e atmosphere. As previously noted, each retort can
1~ hav~ its o~n env;xonrnental cleansing/by-product extraction
~t) h~rd~ar~ Lt is also possible to entrain the wastes in -the
2l ¦ ]ceroyen and permit ~Jaste removal at the refinery where waste
22 1 txeatment facilities already exist.
23 1 Since }~erogen tends to become "jello-like" in
24 ¦ consistency when its temperature drops below 85~F., individual ~ -
1 product lines 38 and site product line 40 as well as storage
26 I tank 42 may be heated, as by being ~rapped by a tubing loop.
~7 1 These loops may be connected to a heat exchanger 50 assoGiated
~3 1l witll each retort. The heat exchanger 50 would recover the
2~ ~I convected heat from the retorts, resulting from on going
30 ll com~ustion and conduct the heat by suitable means to heat the
31 ji individual product lines, the si-te product line~ as well as the
32 1 kerogen storage tank~ The heat of the on-going cornbustion in
Il , I
1 1 each retort is utilized to maintain the kerogen in a fluid
2 1¦ state. Heat can also be recovered from the spent shale clinker
3 1l and if desired the recovered heat can be used to dis~ill off
4 ¦l certain fractions of the l~erogen after it has beén recovered
~I from the oil shale.
6 1I FIG. 3 is a schematic representation of the portable
7 1I nature o~ each of the individual retorts~ As can be seen in
8 Ij EI~ 3, conveyer belt 28 is utilized to carry the oil bearing
9 shale Erom stockpile 26 to -the retor~ 24. Manual controls 32
ll associated ~ith the individual retort 24 are utilized by the
operator thereof to regulate the amount of shale desirea to be
processed by that particular retort 24. An electrical input
~L3 1¦ line 26 is coupled through an electrical plug to retort 24 to
~ provide the necessary electrical power or operating the
hydraulics, suction blower, gear motor, and other electrical
J6 devices thereon. It is old and well-known to place a ~Jatt
17 met~r in such a line so as to measure the amount of power being
1~3 corlsum~d by the unit so that the operator can be billed
~9 ~ccordingl~.
Not dep:;ct:ed is -the skld-mounting for the retorts.
21 ¦ This is conventiorlal in nature and tractors or o-ther similar
22 1I movers cc~n be attached to the s]id-mounting to move the
23 1¦ individual re-torts to any site desired. It will be evident that
24 1¦ other means equivalent to skid mounts can be use~ to make the I -
I retorts portable or, if desired, motor means on the retort
26 ~ itsel operatively connected to motive means; i~e., wheels,
27 ! contirluous trac~, and the like, mounted on the bot-tom of the
~8 jl retorts can be used to move the retorts when desired.
29 ll The kerogen produced by retort 24 during the
30 1I cor~ustion operations is collected through line 38 which
31 ¦! transfers the kerogen through a site product line to the
32 kerogen storage tan]. Vol~e moni-tor 4~ records the quc~ltity
Ij I
12- !
1 I of kerogen prodllced by the individual retort, if individual
2 ~ operators are used. The retort operator is paid according to
3 ¦ this vol~lle figure This kerogen connecting line may be
4 I coupled to retort ?4 by means of a quick disconnect coupling in
I a manner that is old and well-known in -the art.
6 I ~n like manner, the gaseous wastes from retort 24
7 ' are collect.ed by waste line ~6 which leads to the environmental
~ c].eansing/hy-product extraction hardware 48 as explained earlierO¦
9 ~ga.i.n, this line may be coupled to retort 24 by means of a
quick disconnect coupling in a manner that is old and well~known
11 ¦ in the art. As previously noted, each retort may have i-ts own
12 I environmental controls.
13 I Finally, heat exchanger 50 may have coupled thereto
1~ ! an outlet line 52 for carryi.ng heat away from the retort 24 and
`15 an inlet line $4 for providing a return flow to retort 24~
l6 ¦~ Line 52 may be used to wrap line 38 and site product line 40
.1.7 ¦ as ~/ell as the kerogen storage tank 42 to maintain the kerogen
~ i in a l.iqui.d state or other alternative uses as previously
i~9 de~cribed.
~0 ¦ The retorts used in the present invention can be any
21 ¦ one of the successfully used retorts such as the Union Oi.l rock
22 ! p~np retorts (Types A and B), the Cameron and Jones kiln, or
23 ¦ the retorts used in the Paraho, Superior, and Tosco oil shale
24 j processes as described on pages 263 to Z70 of the text ~'The
I Energy Source Bookl', edited by McRae et al~ Certain of these
26 I and other retorts are disclosed in U.S. Patents No 2,875~137
27 ¦ to LiefEers et al, No. 3,162,583 to Hemrningef et al, and No~
28 1 3,908,865 to Day. These retorts are cited for illustrative
29 ¦ purposes only and not by way of limitation. It is also pointed
¦ out that th~se retorts must be made of a size to be portative
31 t and provided with means to make them portative~
32 I FIG~ 4 illustrates a preferred embodirnent of the
-1.3-
1 ¦ present invention wherein under~roun~ mining and recovery of
2 l¦ the oil i.s effected. There is shown a conventional room and
3 ¦¦ pillar rnine 70 having sufficient pillars 71 to s~ppor-t the
~ ¦I mine. Conventional mining equipment (not shown) is used to
¦i mine the shale from the mi.ne face and the shale is conveyed,
6 ll as by front-end loaders 72, to conventional crushers 73. TheJ
7 I crushed shale is moved by con~eyors 74 to a screen 99, then
8 1I through a second crusher 75 (if necessary)l and then the crushed
9 ~! ore is placed into feeder piles 76 by radial stacker 95.
pl.urality of conveyors 77 carry the crushed shale from piles 76
~ to retorts 78. The kerogen is moved by pipes 79 to storage tank
12 1l 80 located on the surface. The other by-products are conveyed
13 jl to recovery tank 90 by pipes 91.
The spent shale is mo~ed by means of conveyors 80 -to
~5 Ij a portion of the mine already mined where it is disposecl of and
l6 ~ he excess spent shale is moved by means of conveyors (not
17 ll shown) to spent shale storage tank 81 where the excess spent
1.~ 1 shale is carried to the surface by suitable elevator means, such
1~ ¦ ~ the c~ntinuous bucket system 82, and onto surface conveyor
~3 :~or transpor-t to a suitable surface dump site. If desired,
21 the spent shale can he treated with a suitable a~ueous solution
~2 .in I:ank 81 to solubilize and remove the alkaline cations
23 therefrom. .These alkaline materials can then be disposed of in
24 the mine thereby eliminating a major problern with respect to .
2~ ¦ sur~ace deposit o~ t~e e~cess spent shale.
26 1l . The system shown in FIG. 5 cor~bines, ayain, room and
27 ¦I pillar mining, but with surface retorting and stationary
28 Ij reto.rts. It is not as econo~ically suitable in that al.l the
29 l¦ oil shale must be conveyed to the surface, not just the e~cess
3~ shale as with the system of the present invention shown in
31 1l FIG. 4. In this er~odiment, the shale mined in mine ~0 is
32 ~I con~eye~ by loader 72 to crusher 73, screened, lifted to th~
li l
~ surface in buckets lOO, and there secondarily crushed. The
2 ll crushed shale is then fed to non-mobile retorts 78 and the
3 l¦ kerogen conveyed to storage tank 80 and other recoverable
4 ll by-products to recovery tank 90. The spent shale to be placed
1I back i.nto the already mined area of the mine can be lowered
6 1! by means of buckets 103 into the mine and conveyed by means of
7 li conveyors 104 to the area where it is to be dumped. Such a
8 ll system i.s siynificantly less economic. In addition, the reduced
9 ¦ ~istances over which the spent shale must be transported is, by
! virkue of the retort mobility, greatly minimized and avoids ~e
ll 1 requirement of slurrying the shale residue as foreseen necessary
12 in the large immobile facil.ities thèreby avoiding -the necessity
13 of large water useage.
1~ The use of small portative retorts is advantageous
.~5 over large retorts even in surface mining in that much less
~.6 I land is required for economic mi.ning as the retorts can be
:l7 ¦ readily moved from place to place over the mining area.
l8 ¦ The process o~ the invention is largely evident from
~ l.he foxeyo,ing description of the apparatus system.
Thus r there has been disclosed an oil recovery system
2,1 .in wh,ich kerogen is recovered from oil-bear,ing shale which
22 permits economic recove.ry and in a manner which allows, if
23 desired, individual operators to share the enormous costs that
24 are involved in the production of such shale oil and yet which .
¦ allows each operator to set up a portable retort on the site of
26 1 -~e oil-bearing shale or to purchase from the land owner or
~7 ¦ other proper individual the a~ount of shale necessary for
28 ¦~ continually operating the retort as many hours a day as
29 l~ necessary and to supply the recovered shale oil to a co~on
~¦ collection system and to have the gaseous waste supplied to a
31 ¦I common collection system for purifica'-tion. The costs thus
32 ¦¦ become managable and allow a shale oil recovery operation ~Jhich
33 ll could not be effectively handled by one operator.
~ ~ile tl)e instant invention has been described in
2 ¦ detail with respect to recovery of oil from oil shale, it i.5
3 I also applicable to recovery of oil from tar s~nd and coal
4 ¦ gasification. The applicability arises from the Eact that in
5 ¦1 these other energy recovery efforts, large scale mining of the
6 ~I sands and coal is well-kno~m and efficient, but -the recovery
7 !1 of the oll from the sand and gasification of the coal have been
~ ¦I hampered by the cost of scaling up the recovery devices; i.e.,
g 1l retorts, kilns r and the like. As with shale oil recovery of
¦ the instant invention, this problem can be overcome by using a
11 ! sufficien~ nu~ber of the already prloven pilot scale recovery
12 11 units which are made portative and which avoid the problems,
13 ! economic and mechanical, of scaling up. In short, the instant
14 1 novel system of mating large scale mining techniques with small
¦ scale portative retorts to provide econo~ic and efficient
L6 recovery of oil from oil shale can be applied to recovery of
17 oil ~rom tar sands and to coal gasification.
18 ~ile the invention has been described in connection
19 with ~ preferred embodiment, it is not intended to limit the
20 I ~cope oE the invention to the particular form set forth but,
21 ' on the contrary, it is intended to cover such alternatives~
22 modifications, and equivalents as may be included within the
23 Ij ~pirit and scope of thé invention as defined by the appended
2~ I claims.
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