Oil Shale, Tar Sands, and Related Materials - American Chemical

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K. M.JAYAKAR1,J. D. SEADER, A. G. OBLAD, and K. C. HANKS Departments of Chemical and Fuels Engineering, University of Utah, Salt Lake City, UT 84112

Oil-impregnated rock d e p o s i t s , more commonly r e f e r r e d to as tar sands, are found on every continent except A u s t r a l i a and A n t a r c t i c a (1). The l a r g e s t known d e p o s i t s occur in northern A l b e r t a , Canada, where two full-scale commercial p l a n t s f o r producing s y n t h e t i c crude oil a r e in o p e r a t i o n and two more p l a n t s have been approved f o r c o n s t r u c t i o n . Of the 24 s t a t e s that cont a i n t a r sands in the United S t a t e s , Ritzma (2) estimates that about 90-95 percent o f these t a r sands lie in Utah. Although the Utah deposits c o n t a i n only about 25 billion b a r r e l s of i n - p l a c e bitumen, compared t o 900 billion b a r r e l s in Canada, as d i s c u s s e d by Oblad et al. (3), the Utah d e p o s i t s represent an important p o t e n t i a l domestic source o f s y n t h e t i c petroleum. Operating p l a n t s in Canada employ a hot-water process f o r r e c o v e r i n g bitumen from t a r sands. Although Utah t a r sands can be c o n s i d e r a b l y d i f f e r e n t from Canadian t a r sands w i t h respect t o p h y s i c a l and chemical p r o p e r t i e s (4), Sepulveda and Miller (5) have s u c c e s s f u l y processed t a r sands from high-grade Utah d e p o s i t s with a m o d i f i e d hot-water process that uses high-shear c o n d i t i o n s to overcome the higher v i s c o s i t y of Utah tar-sand bitumens. More recent work by M i s r a and Miller (6) has been s u c c e s s f u l in processing medium-grade Utah d e p o s i t s . Other methods f o r p r o c e s s i n g tar sands that have been s t u d i e d e x t e n s i v e l y (1) i n c l u d e v a r i o u s in-situ techniques and mining followed by d i r e c t coking, s o l v e n t e x t r a c t i o n , or cold-water s e p a r a t i o n . Of the other methods that use mined m a t e r i a l as the feed stock, d i r e c t coking processes, g e n e r a l l y r e f e r r e d to as thermal recovery methods, appear t o exhib i t the most promise as a l t e r n a t i v e s to hot-water processing because thermal recovery methods avoid handling of v i s c o u s bitumen, recovery of sediment from s o l u t i o n s , and recovery and r e c y c l e of water and/or s o l v e n t s . In the work presented here, a new energye f f i c i e n t thermal process was developed and a p p l i e d to t a r sands from three Utah d e p o s i t s . 1

Current address: Eastman Kodak Company, Rochester, NY, 14605.

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Current address: Celanese Chemical Company, Pampa, TX, 78408. 0097-6156/81/0163-0359$05.00/0 © 1981 American Chemical Society

Stauffer; Oil Shale, Tar Sands, and Related Materials ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

OIL SHALE, TAR SANDS, AND RELATED

360 Thermal Recovery

MATERIALS

Process

The concept of r e c o v e r i n g l i q u i d and/or gaseous hydrocarbons from s o l i d hydrocarbon-bearing m a t e r i a l s by thermal treatment has been known f o r s e v e r a l c e n t u r i e s (7). Thermal treatment essent i a l l y e n t a i l s p r o c e s s i n g at high temperature. In most thermal processes, the feed m a t e r i a l i s heated i n an i n e r t or nono x i d i z i n g atmosphere. The mode of h e a t i n g and the operating temperature l a r g e l y determine the type of changes o c c u r r i n g to the feed, which can i n c l u d e : 1) v o l a t i l i z a t i o n of any low-molecularweight components i n the feed, 2) generation of vapors by c r a c k i n g r e a c t i o n s , and 3) conversion of part of the m a t e r i a l i n t o coke, by r e a c t i o n s such as p o l y m e r i z a t i o n . In the case of feed m a t e r i a l s such as t a r sand, which c o n t a i n a s i g n i f i c a n t amount of s i l i c a sand or other i n o r g a n i c i n e r t matter that remains s u b s t a n t i a l l y unchanged through the thermal treatment, coke i s obtained as a deposit on the i n o r g a n i c matter. Thermal p r o c e s s i n g can r e q u i r e a s u b s t a n t i a l input of energy to provide the necessary s e n s i b l e , l a t e n t , and r e a c t i o n h e a t s . However, as d i s c u s s e d by Oblad et a l . (3), coke, when produced as above and subsequently combusted, can g e n e r a l l y provide much or a l l of t h i s energy requirement. Combustion, r e f e r r e d to some authors as decoking or burning, i s t h e r e f o r e an important aspect of thermal-recovery methods. Moore et a l . (8) c l a s s i f y thermal processes i n t o two general groups, d i r e c t heated and i n d i r e c t heated, depending on whether p y r o l y s i s and combustion steps are c a r r i e d out i n one or two r e a c t i o n v e s s e l s . The processes f u r t h e r d i f f e r from each other with r e s p e c t to f l u i d i z e d - b e d or moving-bed s t a t e of s o l i d s i n each of the two s t e p s . Table I shows a general process c l a s s i f i c a t i o n scheme that f i t s most known thermal processes. References are i n c l u d e d i n that t a b l e . Regardless of the thermal process used, as d i s c u s s e d i n d e t a i l by Bunger (4), the s y n t h e t i c crude o i l product obtained cannot, i n general, be used as a subs t i t u t e f o r crude petroleum but must be upgraded to reduce s u l f u r and n i t r o g e n contents, average molecular weight, and C/H r a t i o . In a l l thermal recovery processes, t a r sand i s subjected to high p r o c e s s i n g temperatures, about 450-550°C f o r p y r o l y s i s , and the r e s i d u a l coked sand i s f u r t h e r heated to about 550-650°C during the combustion s t e p . At these c o n d i t i o n s , an acceptable thermal e f f i c i e n c y can only be obtained i f a s i g n i f i c a n t p o r t i o n of the s e n s i b l e heat i n the spent sand i s recovered and introduced back i n t o the process. Almost a l l the processes i n Table I provide f o r heat recovery from spent sand before i t i s d i s c a r d e d . Perhaps the best-known f l u i d i z e d - b e d process i s the one developed by G i s h l e r and Peterson (17, 24-, 25) i n Canada. The process scheme resembles that of c a t a l y t i c c r a c k i n g as used i n the petroleum i n d u s t r y . Tar sand i s fed to the p y r o l y s i s or coker bed, where the o i l vapor produced i s c a r r i e d by the f l u i d i z i n g gas to the product c o l l e c t i o n system. Coked sand i s withdrawn from the coker and blown by preheated a i r i n t o the burner where the coke


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i s burned. A p o r t i o n of the hot sand i s r e c y c l e d to the coker to supply heat f o r the p y r o l y s i s step, with the remainder d i s c a r d e d through an overflow pipe i n the burner bed. Two s e r i o u s drawbacks of t h i s process, as noted by Camp (1), are the l a r g e r e c y c l e of hot sand r e q u i r e d and the high energy content of the net spent sand. Rammler (23) has d e s c r i b e d the a p p l i c a t i o n of the L u r g i Ruhrgas process to t a r sands. L i k e the G i s h l e r and Peterson process, i t uses sand as the heat c a r r i e r . Development of an E n e r g y - E f f i c i e n t Thermal

Process

The p a r t i c u l a t e nature of the m i n e r a l matter i n most t a r sands permits f l u i d i z e d p r o c e s s i n g with s e v e r a l advantages: 1) d i s i n t e g r a t i o n of lumps of t a r sand to i n d i v i d u a l p a r t i c l e s upon the p y r o l y s i s of the bitumen; hence such feeds do not have to be reduced to a s m a l l s i z e p r i o r to entry i n t o the p y r o l y s i s reactor; 2) r e l a t i v e ease of handling s o l i d s because f l u i d i z e d s o l i d s flow through pipes l i k e l i q u i d ; 3) h i g h h e a t - t r a n s f e r r a t e s between f l u i d i z i n g medium and s o l i d p a r t i c l e s ; 4) n e a r l y i s o t h e r m a l operat i o n , which permits c l o s e c o n t r o l of the temperature of p y r o l y s i s , a v a r i a b l e a f f e c t i n g product y i e l d s , q u a l i t y and energy r e q u i r e ments; 5) high r a t e s f o r mass t r a n s f e r between p a r t i c l e s u r f a c e and f l u i d i z i n g medium, which i s important f o r a h i g h r a t e of feed per u n i t area without forming agglomerates; 6) accommodation of v a r i a t i o n s i n bitumen content of feed by r e g u l a t i n g the flow of f l u i d i z i n g gas; and 7) ease of immersion of heat t r a n s f e r tubes or heat exchangers i n the f l u i d i z e d beds w i t h accompanying h i g h h e a t - t r a n s f e r c o e f f i c i e n t s . The l a s t f a c t o r i s p a r t i c u l a r l y important f o r the type of process developed i n t h i s study and c o n s t i t u t e s the primary reason f o r the choice here of f l u i d i z e d p y r o l y s i s . A f l u i d i z e d bed recommends i t s e l f f o r burning coke f o r e s s e n t i a l l y the same reasons as f o r p y r o l y s i s and was used, t h e r e f o r e , f o r the process developed here. P r e v i o u s l y developed processes employ v a r i o u s f e a t u r e s to accomplish heat t r a n s f e r f o r preheat and p y r o l y s i s . These i n clude 1) preheating the tar-sand feed, s e p a r a t e l y from the p y r o l y s i s step, g e n e r a l l y to recover heat from outgoing hot gaseous streams; 2) preheating the incoming process gas streams, genera l l y to recover heat from spent sand or s o l i d s r e s i d u e l e a v i n g the process; 3) t r a n s f e r of heat from the burner to the p y r o l y s i s r e a c t o r i n the form of s e n s i b l e heat of gases l e a v i n g the burner, g e n e r a l l y by d i r e c t heat exchange with the contents of the p y r o l y s i s zone; and 4) i n t e r n a l combustion of coke i n the p y r o l y s i s r e a c t o r i t s e l f with a c o n t r o l l e d amount of o x i d i z i n g gas so that only a p o r t i o n of the hydrocarbons i n the p y r o l y s i s zone, p r e f e r ably coke, i s combusted; 5) t r a n s f e r from the burner to the p y r o l y s i s step by r e c y c l e of hot, spent sand as a heat c a r r i e r . Feature 1 has not been shown to be p r a c t i c a l because, when preheated, t a r sand becomes s o f t and s t i c k y , making i t impossible


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to feed by common feeding devices such as a screw conveyor. Feature 2 can be and g e n e r a l l y i s incorporated i n t o most thermal processes. However, a maximum of only about 25 percent of the energy i n the hot, spent sand can be recovered by preheating the o x i d i z i n g g^s f o r coke combustion. In Feature 3, the amount of energy that can be c a r r i e d by gases from the combustion zone to the p y r o l y s i s zone i s r e l a t i v e l y s m a l l . Feature 4 r e q u i r e s a means f o r d i r e c t heat t r a n s f e r between the two zones by conduct i o n , convection, and/or r a d i a t i o n . Unless t h i s can be accomp l i s h e d on a l a r g e s c a l e w i t h l i t t l e or no combustion of bitumen, Feature 4 i s not p r a c t i c a l . Feature 5 i s p r a c t i c a l , but excessive r e c y c l e of hot, spent sand i s r e q u i r e d , thus g r e a t l y i n c r e a s i n g the r e q u i r e d s i z e s of p y r o l y s i s and combustion r e a c t o r s and n e c e s s i t a t i n g l a r g e devices to convey the sand. Another p o s s i b l e means of t r a n s f e r r i n g heat from the cokecombustion stage to the p y r o l y s i s stage i s by the use of i n d i r e c t heat exchange not i n v o l v i n g sand or gas. In the process developed i n t h i s work, t h i s means was implemented by i n c o r p o r a t i n g heat pipes to t r a n s f e r the bulk of the energy r e q u i r e d f o r s o l i d preheat and p y r o l y s i s from the coke-combustion stage. A heat pipe, f o r the purpose here, may be d e f i n e d simply as a completely enclosed tubular device w i t h very high e f f e c t i v e thermal conductance, which t r a n s f e r s heat by two-phase c i r c u l a t i o n of a working f l u i d (28). In o p e r a t i o n , heat i s t r a n s f e r r e d to one end of the heat pipe, causing the working f l u i d to v a p o r i z e . The vapor flows to the other, c o o l e r end due to the pressure g r a d i e n t s e t up i n s i d e the c e n t r a l vapor core of the heat p i p e . There, the vapor condenses on the tube w a l l and i n s i d e a wick, t r a n s f e r r i n g heat to the surroundings. The condensate then returns to the warmer end, thus completing the c y c l i c flow of the f l u i d . Because a l a r g e amount of heat can be t r a n s f e r r e d by a heat pipe, i t s s o - c a l l e d e f f e c t i v e thermal c o n d u c t i v i t y can be extremely h i g h . For a p p l i c a t i o n to thermal processing of t a r sands, potassium was s e l e c t e d as the working f l u i d . The e s s e n t i a l f e a t u r e s of the r e a c t o r system f o r the new thermal process developed i n the work reported here are i l l u s t r a t e d i n the s i m p l i f i e d process scheme of F i g u r e 1. F r e s h l y mined and s i z e d t a r sand i s dropped i n t o the upper bed of a m u l t i staged f l u i d i z e d - b e d column. The upper bed i s a p y r o l y s i s r e a c t o r , which i s maintained a t a temperature of g e n e r a l l y between 400° and 550°C. Here, bitumen i n the feed i s cracked and/or v o l a t i l i z e d , l e a v i n g a coke deposit on the sand p a r t i c l e s . The o i l vapors and l i g h t hydrocarbon gases produced are c a r r i e d o f f by the i n e r t f l u i d i z i n g gas to f i n e s - s e p a r a t i o n and productrecovery s e c t i o n s , w h i l e coked sand flows down by g r a v i t y through a c o n t r o l v a l v e to the burner s e c t i o n of the column where the coke i s burned to generate heat. The burner i s maintained at a temperature of g e n e r a l l y between 550° and 650°C. Preheated a i r i s used to f l u i d i z e the s o l i d s i n the combustion bed and to pro-


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T a r Sand

Pyrolysis

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tit

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Heat Recovery

Air .

*Sc 'Spent Figure 1.

Sand

University of Utah process


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MATERIALS

v i d e oxygen f o r combustion. Gaseous products of combustion, mostly n i t r o g e n and carbon d i o x i d e , then flow upwards to f l u i d i z e s o l i d s i n the upper bed as noted above. A number of heat pipes, as r e q u i r e d by the h e a t - t r a n s f e r load, are placed v e r t i c a l l y i n the f l u i d i z e d - b e d column such that they extend i n t o the p y r o l y s i s and combustion beds as d e p i c t e d i n F i g u r e 1. The heat pipes t r a n s f e r excess heat generated i n the burner to the p y r o l y s i s r e a c t o r , thus m a i n t a i n i n g the r e a c t o r and burner at proper temperatures. Hot, spent sand l e a v i n g the burner flows down through a cont r o l v a l v e to a heat-recovery s e c t i o n , where process a i r recovers heat from the spent sand. A d d i t i o n a l energy can be recovered from the sand by heat exchange to produce steam. A more d e t a i l e d d e s c r i p t i o n of the process i s given by Seader and Jayakar (26). The new process r e t a i n s most of the s i m p l i c i t y of d i r e c t heated processes. S o l i d s move only downwards by g r a v i t y , the equipment i s e s s e n t i a l l y a s i n g l e v e s s e l , and there i s no r e c y c l e of s o l i d s . Most importantly, the h e a t - t r a n s f e r f e a t u r e s u s e d — heat p i p e s , heat recovery from spent sand to preheat process a i r , t r a n s f e r of some heat by combustion gases, and some r a d i a t i v e heat t r a n s f e r from coke-combustion stage to the p y r o l y s i s r e a c t o r — permit e f f i c i e n t management of the energy that i s w i t h i n t a r sand i t s e l f to h e l p achieve high energy e f f i c i e n c y . The heat pipes e f f e c t i v e l y l i n k the p y r o l y s i s r e a c t o r and the coke-combustion stage thermally without n e c e s s a r i l y imposing any other c o n s t r a i n t s on the process such as flow p a t t e r n s , r e a c t o r c o n f i g u r a t i o n , or dimensions of the column (except f o r the volume of heat pipes, which i s a s m a l l f r a c t i o n of bed volumes). The b a s i c process as o u t l i n e d above i s very f l e x i b l e , and m o d i f i c a t i o n s and v a r i a t i o n s can be e a s i l y i n c o r p o r a t e d i n t o i t to f u r t h e r improve the o v e r a l l e f f i c i e n c y and/or to make i t more s u i t a b l e f o r s p e c i f i c types of feeds. Thus, e x t e r n a l f u e l , r e c y c l e gas, or l i q u i d f u e l s can be e a s i l y introduced i n t o the burner i n the case of l e a n t a r sands. By p r o v i d i n g f o r a purge gas stream o f f the top of the combustion bed, one can adjust the flow r a t e of f l u i d i z i n g gas to the p y r o l y s i s bed. I f desired, after recovery, gas produced i n the p y r o l y s i s bed can be r e c y c l e d back to that bed and used i n s t e a d of combustion gases to f l u i d i z e i t . This i s very important f o r l e a n t a r sands which would otherwise have very low product c o n c e n t r a t i o n i n the combined e x i t gas stream, making product recovery d i f f i c u l t . Laboratory T e s t i n g of New

Process

A l a b o r a t o r y apparatus was used to demonstrate the new t h e r mal process. I t c o n s i s t e d of a 10-foot-high by nominal 2-inch diameter, two-staged, f l u i d i z e d - b e d column, a screw feeder f o r feeding t a r sand, a hot cyclone and f i l t e r system f o r s e p a r a t i o n of f i n e s from the products, and a product-recovery s e c t i o n c o n s i s t ing of condensers, phase s e p a r a t o r s , cyclones, and an e l e c t r o -


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s t a t i c p r e c i p i t a t o r . A s i n g l e 0.75-inch-diameter by 7-foot-long heat pipe extended i n t o the p y r o l y s i s and coke-combustion beds. The apparatus was completely i n s u l a t e d and instrumented with thermocouples, pressure taps, flow meters, and sampling taps. E l e c t r i c a l heaters and a propane burner were used to provide heat during s t a r t u p c o n d i t i o n s . The equipment was designed to handle a nominal feed r a t e of 5 l b / h r of t a r sands c o n t a i n i n g up to 14 weight percent bitumen. F u r t h e r d e t a i l s of the apparatus are given by Jayakar (27). Several problems i n s o l i d s handling were encountered i n operating the l a b o r a t o r y apparatus. O r i g i n a l l y s o l i d s were transf e r r e d from the p y r o l y s i s bed to the combustion bed by means of a weir and d i p l e g . Because gas tended to flow up through the d i p l e g , t h i s system was abandoned i n favor of a simple s o l i d s downcomer with a s p e c i a l l y designed s o l i d s f l o w - c o n t r o l v a l v e . Although t h i s v a l v e permitted proper o p e r a t i o n of the bed, i t was a r e c u r r e n t source of o p e r a t i n g d i f f i c u l t y as i t tended to s t i c k a f t e r a few runs and had to be dismantled and cleaned every two to f o u r runs. Flow of s o l i d s from the combustion bed was cont r o l l e d by a s i m i l a r v a l v e , which presented no o p e r a t i n g problems. Tar-sand feed m a t e r i a l s were ground to p a r t i c l e s or p i e c e s no l a r g e r than about 1/4-inch i n s i z e . M a t e r i a l s tending to be s t i c k y were dusted with f i n e s o r c o a l dust p r i o r to f e e d i n g . The screw feeder d i d not plug as long as i t was kept a t a nearambient temperature. Run d u r a t i o n s were t y p i c a l l y one hour a f t e r spending s e v e r a l hours to reach e s s e n t i a l l y s t e a d y - s t a t e conditions. The experimental work was d i v i d e d i n t o three p a r t s : f l u i d i z a t i o n s t u d i e s a t elevated temperatures, p r o c e s s i n g of t a r sands i n the p y r o l y s i s s e c t i o n without use of the heat pipe, and o p e r a t i o n of the complete heat-piped apparatus. Only t y p i c a l r e s u l t s o f some of the l a t t e r t e s t s are reported here. A t o t a l of 75 runs was made under thermal p r o c e s s i n g c o n d i t i o n s a t near-ambient pressure with t a r sands from three d i f f e r ent d e p o s i t s : Tar Sand T r i a n g l e , Sunnyside, and Asphalt Ridge. Data from r e p r e s e n t a t i v e runs f o r feed m a t e r i a l s from each o f the three d e p o s i t s a r e given i n Table I I . A complete accounting of a l l the bitumen i n the feed m a t e r i a l was g e n e r a l l y not achieved mainly because of d i f f i c u l t i e s i n removing o i l product from the product recovery equipment. Thus, values reported f o r o i l y i e l d are b e l i e v e d to be low. Based on the best runs, i t i s estimated that f o r Sunnyside and Asphalt Ridge m a t e r i a l s , a t y p i c a l y i e l d s t r u c t u r e f o r near-optimal operating conditions would be: 70 wt% o i l , 10 wt% gas, and 20 wt% coke. Conclusions 1. The b a s i c concept of a thermal process using p y r o l y s i s and combustion stages coupled by heat pipes i s workable and e l i m i n a t e s the need to r e c y c l e l a r g e amounts o f sand.



366 Table I .

C l a s s i f i c a t i o n o f and References f o r Thermal Recovery Processes

I n d i r e c t Heated

D i r e c t Heated Moving-bed p y r o l y s i s and combustion

Cheney et a l . (9) Dannanberg and Matzick (10) Saunders (11)

Bennett (12) Berg (13) F i t c h (14)

Fluidized-bed pyrolysis and combustion

G i f f o r d (15) Peck et a l . (16)

G i s h l e r and Peterson (17) Nathan e t a l . (18) R o e t h e l i (19) Murphree (20) Alleman (21)

Fluidized-bed pyrolysis and moving-bed combustion

Donnelly

No examples known

Moving-bed p y r o l y s i s f l u i d i z e d - b e d combustion

No examples known

Table I I .

et a l . (22)

Rambler (23)

Laboratory R e s u l t s f o r Processing of Utah Tar Sands Deposit Tar

Run No. Bitumen Content of Feed, wt% Tar-Sand Feed Rate, lb/hr P y r o l y s i s Bed Temperature, °C Combustion Bed Temperature, °C O i l Y i e l d , wt% Gas Y i e l d , wt% Coke Y i e l d , wt% T o t a l Y i e l d , wt% API G r a v i t y of O i l , 20 °C V i s c o s i t y of O i l , cps, 25°C

Sand T r i a n g l e 58 4.70

Asphalt Ridge

Sunnyside

67

74

11.67

10.56

3.90

4.41

3.85 475 482

449

649

604

603

20.6 22.0 92.1

52.7 15.7 7.8 76.2

45.4 6.2 17.2 68.8

13.1

15.2

18.2

49.5

142

102

291


24.

JAYAKAR

ET AL.

Thermal

Recovery

of

Oil

367

2. Tar sands c o n t a i n i n g as low as 8 percent bitumen can be thermally processed without e x t e r n a l energy input to get s a t i s f a c t o r y y i e l d s of o i l . Tar sand with even lower bitumen content can be processed with good o i l y i e l d i f a p o r t i o n o f the gas or o i l products or some cheaper e x t e r n a l f u e l , such as c o a l , can be added to the combustion stage to provide energy. 3. M o d i f i c a t i o n s of the process, such as i n t r o d u c i n g recycle of gas and o i l , a l l o w i n g f o r purge o f some combustion gas, e t c . , can improve the energy e f f i c i e n c y o f the process and the y i e l d s of o i l and gas. 4. The process developed during the course of t h i s work i s simple, d i r e c t , and e f f i c i e n t . I t i s capable of wide a p p l i c a t i o n to processing o f t a r sands i n Utah, Canada, and perhaps other d e p o s i t s . Moreover, the concept of using heat pipes i s o f even broader a p p l i c a b i l i t y i n the process i n d u s t r i e s i n general and i n e n e r g y - r e l a t e d i n d u s t r i e s i n p a r t i c u l a r . For example, the b a s i c processing concepts i n v e s t i g a t e d here may have p o t e n t i a l f o r a p p l i c a t i o n i n the processing of o i l shale and c o a l .

ABSTRACT Tar sands from the Asphalt Ridge, Sunnyside, and Tar Sand Triangle deposits in Utah were processed in a small-scale, two-stagefluidized reactor system operating under continuous, steady-flow conditions. The oil products obtained were analyzed for viscosity, refractive index, density, sulfur content, distillation yield, and proton nmr spectra. In the first stage of the reactor, mined and suitably sized tar sand is pyrolyzed at temperatures of 450 to 500°C in an inert atmosphere to crack and volatilize most of the contained bitumen, which is then condensed and collected to give a synthetic crude oil. In the second stage, coke formed as a by-product in the first stage is combined with air at temperatures of 550 to 650°C. The energy released during combustion in the second stage is transferred by a heat pipe to the first stage where the heat is utilized to provide for preheat and heat of pyrolysis of tar-sand feeds. Gaseous combustion products from the second stage, containing very little oxygen, are used to fluidize the pyrolysis bed. The process permits recovery of oil from tar sands with high energy efficiency in a once-through operation with respect to sand. References

1. Camp, F. W., "Tar Sands" in Kirk-Othmer Encyclopedia of Chemical Technology, 2nd Edition, Vol. 19, John Wiley and Sons, New York, pp. 682-732 (1969). 2. Ritzma, H. R., AIChE Symposium Series No. 155, 72, 47 (197 3. Oblad, A. G., J. D. Seader, J. D. Miller, and J. W. Bunger, AIChE Symposium Series No. 155, 72, 69 (1976).


368


4. Bunger, J. W., K. P. Thomas, S. M. Dorrance, Fuel 58, 183 (1979). 5. Spulveda, J. E., and J. D. Miller, Mining Engineering, 30, 1311 (1978). 6. Misra, M., and J. D. Miller, Mining Engineering, 32, 302 (1980). 7. Gustafson, R. E., "Shale Oil" in Kirk-Othmer Encyclopedia of Chemical Technology, 2nd Edition, Vol. 18, John Wiley and Sons, New York, pp 1-20 (1969). 8. Moore, R. G., D. W. Bennion, J. K. Donnelly, "Anhydrous Extraction of Hydrocarbons from Tar Sands," Paper presented at local ISA Meeting, Calgary Section, April 1975. 9. Cheney, P. E., R. W. Ince, and C. M. Mason, U. S. Patent 3,487,002, December 30, 1969. 10. Dannanberg, R. O., and A. Matzick, "Bureau of Mines Gas-Combustion Retort for Oil Shale," U. S. Bureau of Mines Report of Investigation 5545 (1960). 11. Saunders, F. J., U. S. Patent 3,130,132, April 21, 1964. 12. Bennett, J. D., U. S. Patent 3,623,972, November 1971. 13. Berg, C. H. O., U. S. Patent 3,905,595, September 22, 1959. 14. Fitch, C. M., U. S. Patent 3,267,019, August 16, 1966. 15. Gifford, P. H., II. U. S. Patent 4,094,767, June 1978. 16. Peck, E. B., E. Tomkins, and D. G. Tomkins, U. S. Patent 2,471,119, May 1949. 17. Gishler, P. E., and W. S. Peterson, Treatment of Bituminous Sand. Canadian Patent 530,920, September 25, 1956. 18. Nathan, M. F., G. T. Skaperdas and G. C. Grubb, U. S. Patent 3,320,152, May 16, 1967. 19. Roetheli, B. E., U. S. Patent 2,579,398, December 18, 1951. 20. Murphree, E. V., U. S. Patent 2,980,617, October 13, 1959. 21. Alleman, C. E., U.S. Patent 2,647,077, July 28, 1953. 22. Donnelly, J. K., R. G. Moore, D. W. Bennion, and A. E. Trenkwalkder, "A Fluidized Bed Retort for Oil Sands," Paper presented at the AIChE Meeting, Florida, 1978. 23. Rammler, A. W., "The Production of Synthetic Crude Oil from Oil Sand by Application of the Lurgi-Ruhrgas Process," Canadian Journal of Chemical Engineering, 48 (October 1970): 552-560. 24. Peterson, W. S., and P. E. Gishler, "A Small Fluidized Solids Pilot Plant for the Direct Distillation of Oil from Alberta Bituminous Sands," Canadian Journal of Research, 28 (January 1950): 62-70. 25. Peterson, W. S., and P. E. Gishler, "Oil from Alberta Bituminous Sand," Petroleum Engineer, 23 (April 1951): 553561. 26. Seader, J. D., and K. M. Jayakar, Process and Apparatus to Produce Synthetic Crude Oil from Tar Sands, U. S. Patent 4,160,720, July 10, 1979. 27. Jayakar, K. M., "Thermal Recovery of Oil from Tar Sands," Ph.D. Thesis in Chemical Engineering, University of Utah (1979). 28. Dunn, P., and D. Reay,HeatPipes,2nd., Pergamon Press, 1978. RECEIVED January 23, 1981. Stauffer; Oil Shale, Tar Sands, and Related Materials ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

Oil Shale, Tar Sands, and Related Materials - American Chemical

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