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FUTURE AVIATION FUELS OVERVIEW Gregory M. Reck N a t i o n a l A e r o n a u t i c s and Space A d m i n i s t r a t i o n L e w i s Research C e n t e r T h i s i n i t i a l s e s s i o n f o c u s e s on t h e o u t l o o k f o r a v i a t i o n f u e l s through t h e t u r n of t h e c e n t u r y and beyond. i s c e r t a i n l y a n a m b i t i o u s t o p i c T h i s c o n s i d e r i n g t h e t u r b u l e n c e i n t h e f u e l supply i n d u s t r y d u r i n g t h e 1970's and t h e u n c e r t a i n t i e s i n f u t u r e petroleum s u p p l i e s , syncrude production, alter- n a t i v e energy s o u r c e s , product demand, and Government r e g u l a t i o n o r i n t e r vention. However, t h e a v i a t i o n community must a d d r e s s t h i s t o p i c i f t h e continued h e a l t h and growth of t h e a i r t r a n s p o r t a t i o n i n d u s t r y i s t o be as- sured.
The g e n e r a l o b j e c t i v e s of t h e NASA L e w i s A l t e r n a t i v e A v i a t i o n F u e l s Research Program a r e t o e v a l u a t e t h e p o t e n t i a l c h a r a c t e r i s t i c s of f u t u r e j e t a i r c r a f t f u e l s , t o determine t h e e f f e c t s of t h o s e f u e l s on engine and f u e l system components, and t o e v o l v e component technology t o u s e t h o s e f u e l s .
The g e n e r a l s t r u c t u r e of t h e program i s i l l u s t r a t e d i n f i g u r e 1. The ele- ment l a b e l e d " i d e n t i f i c a t i o n of f u t u r e fuels'' encompasses a c t i v i t i e s t o de- termine t h e range of p r o b a b l e p r o p e r t i e s of f u t u r e f u e l s and t o examine t h e e f f e c t of varying f u e l p r o p e r t i e s on t h e f u e l supply system. T h i s element encompasses most of t h e a c t i v i t i e s i n t h e program which are a p p r o p r i a t e t o t h i s s e s s i o n . The a c t i v i t i e s d i r e c t e d toward i d e n t i f y i n g t h e e f f e c t s of broadened-property f u e l s on a v i a t i o n systems and evolving technology t o u s e t h o s e f u e l s are s e p a r a t e d i n t o two elements, f u e l system R&T and combustion R&T. Both of t h e s e R&T e f f o r t s r e l y o n t h e " f u e l s and combustion fundamen- t a l s " a c t i v i t i e s f o r s u p p o r t i n g research. The R&T and fundamentals elements w i l l be d e s c r i b e d i n subsequent s e s s i o n s . The f i n a l element, c o n s i s t i n g of s y s t e m s a n a l y s i s s t u d i e s , i s t h e c u l m i n a t i o n of t h e program. These w i l l i n v o l v e e x t e n s i v e economic and e n g i n e e r i n g trade-off s t u d i e s t o e v a l u a t e t h e e f f e c t s of changing f u e l p r o p e r t i e s on t h e o v e r a l l f u e l production and a i r t r a n s p o r t a t i o n system.
A breakdown of t h e f u t u r e f u e l s element, shown i n f i g u r e 2, i n d i c a t e s f o u r subelements o r t a r g e t s .
The f i r s t of t h e s e i s d i r e c t e d toward d e t e r - mining t h e range of p r o b a b l e p r o p e r t i e s of f u t u r e f u e l s . Within t h i s t a r g e t a n experimental in-house s t u d y i s under way t o i n v e s t i g a t e t h e e f f e c t of p r o c e s s i n g t e c h n i q u e and s e v e r i t y o n t h e c h a r a c t e r i s t i c s of j e t f u e l s pro- duced from s y n t h e t i c crudes. The in-house r e f i n e r y s t u d i e s have used a re- f i n e r y model ( r e f . 1 ) assembled under a c o n t r a c t w i t h Gordian A s s o c i a t e s t o study t h e e f f e c t of f e e d s t o c k q u a l i t y , r e f i n e r y c o n f i g u r a t i o n , and product s p e c i f i c a t i o n s on y i e l d ( r e f . 2). An e x t e n s i o n of t h i s work w i l l examine t r e n d s i n a v i a t i o n f u e l r e f i n e r y y i e l d s , c o s t , and energy consumption. A more e x t e n s i v e modeling a c t i v i t y h a s been under way a t t h e U n i v e r s i t y of C a l i f o r n i a a t Los Angeles f o r s e v e r a l y e a r s t o g e n e r a t e p r o j e c t i o n s of j e t f u e l supply and demand ( r e f . 3 ) . T h i s work w i l l be d e s c r i b e d i n a paper l a t e r i n t h i s s e s s i o n . E v e n t u a l l y w e p l a n t o c o u p l e t h e r e f i n i n g and pro- c e s s i n g s t u d i e s w i t h s t u d i e s of t h e e f f e c t s of f u t u r e f u e l s on a i r c r a f t and e n g i n e systems t o i d e n t i f y t r a d e - o f f s a s s o c i a t e d w i t h changes i n f u e l prop- e rt i e s.
The o b j e c t i v e of t h e second t a r g e t shown i n f i g u r e 2 i s t o evolve im- proved c o r r e l a t i o n s of f u e l s t r u c t u r e o r composition w i t h p h y s i c a l and chem- i c a l c h a r a c t e r i s t i c s . The Colorado School of Mines i s n e a r i n g completion of a r e s e a r c h program t o s t u d y c o r r e l a t i o n s between o r g a n i c n i t r o g e n compounds and s t o r a g e and thermal s t a b i l i t y . T h i s program as w e l l a s in-house s t u d i e s i n t h e area of thermal s t a b i l i t y w i l l be d e s c r i b e d i n S e s s i o n I V . With re- gard t o p h y s i c a l p r o p e r t i e s , a r e s e a r c h program w a s r e c e n t l y i n i t i a t e d a t t h e Massachusetts I n s t i t u t e of Technology t o d e r i v e improved c o r r e l a t i o n s of f r e e z i n g p o i n t and v i s c o s i t y w i t h f u e l composition.
The t h i r d t a r g e t i n f i g u r e 2 , a n a l y t i c a l methods, c o n s i s t s of a c t i v i - t i e s t o i d e n t i f y and s o l v e problems i n c h a r a c t e r i z i n g broadened-property f u e l s . T h i s work w i l l a l s o be d e s c r i b e d i n a paper l a t e r i n t h i s s e s s i o n .
The f i n a l t a r g e t i n v o l v e s t h e a c q u i s i t i o n of t e s t f u e l s which w i l l be used throughout t h e v a r i o u s in-house and c o n t r a c t e d f u e l s r e s e a r c h pro- A workshop w a s h e l d a t t h e L e w i s Research C e n t e r i n 1977 t o i d e n t i f y j e c t s .
a r e f e r e e f u e l w i t h broadened p r o p e r t i e s which c o u l d be used i n t e s t pro- grams ( r e f . 4 ) . T h i s f u e l , d e s i g n a t e d t h e e x p e r i m e n t a l r e f e r e e broadened- s p e c i f i c a t i o n f u e l o r ERBS f u e l h a s been procured and i s d e s c r i b e d and char- a c t e r i z e d i n r e f e r e n c e 5. I n a d d i t i o n , blending s t o c k h a s been i d e n t i f i e d which c a n be blended w i t h t h e ERBS f u e l t o produce a v a r i a t i o n i n hydrogen c o n t e n t w i t h a minimal e f f e c t o n o t h e r f u e l p r o p e r t i e s .
The p a p e r s i n t h i s s e s s i o n c o v e r a range of t o p i c s from c u r r e n t f u e l t r e n d s t o f o r e c a s t s of f u t u r e f u e l s and t h e u t i l i z a t i o n of shale-derived syncrudes. The p r e s e n t e r s i n c l u d e r e p r e s e n t a t i v e s of n e a r l y every major s e c t o r of t h e a v i a t i o n f u e l community, t h e f u e l s u p p l i e r s , t h e manufactur- ers, t h e a i r l i n e s , and t h e Government. The material presented should n o t only i d e n t i f y t h e s t a t u s and r e s u l t s of c u r r e n t a c t i v i t i e s , but a l s o high- l i g h t areas where a d d i t i o n a l r e s e a r c h i s needed.
REFERENCES 1. Dunbar, D. N . ; and Tunnah, B. G.: Computer Model f o r R e f i n e r y O p e r a t i o n s w i t h Emphasis on Jet F u e l Production. Volume I: Program D e s c r i p t i o n .
Gordian A s s o c i a t e s , I n c . , Rept. -1099-1-Vol. . l , NASA CR-135333, 1478.
2. F l o r e s , F. J.: Use of R e f i n e r y Computer Model t o P r e d i c t Jet F u e l Produc- t i o n . NASA TM-79203, 1979.
3. E n g l i s h , J. M.; and L i u , C. Y . : F o r e c a s t of F u t u r e A v i a t i o n Fuels.
P a r t I: S c e n a r i o s . UCLA Report ENG 77-78 (NASA Grant N S G 3116), Nov. 1977.
4. Longwell, J. P . , ed. : A i r c r a f t Hydrocarbon Fuels Technology. NASA CP-2033, 1978.
5 . Prok, G . M.; and Seng, G . T. : I n i t i a l Characterization of an E x p e r i - mental Referee Broadened-Specif i c a t i o n (ERBS) Aviation Turbine Fuel.
NASA TM- 8 1440, 19 80.
AIRCRAFT RESEARCH AND TECHNOLOGY FOR FUTURE FUELS
0 FUEL - FLEXIBLE
AIRCRAFT TECHNOLOGY 0 GUIDANCE TO FUELS USERS & SUPPLIERS 0 ASTM FUEL BROAD PROPERTY S PEClFlCATlON GUIDANCE e EMISSION STANDARDS GUIDANCE CS -8045% Figure 1
NASA LEWIS ACTIVITIES DIRECTED TOWARD IDENTIFICATION OF
FUTURE AVIATION FUELS FUTURE FUELS
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CORRELATE RANGE OF STRUCTURE ANALYTICAL PROBABLE WITH METHODS CHARACTERISTICS CORRELATE SYNTHETIC FUELS HYDROPROCESSING STABILITY
LNEW OR L BLENDING
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REFINERY STUDIES PHYSICAL MODIFIED STOCK TECHNIQUES SUPPLY & DEMAND PROJECTIONS AIRCRAFT TECHNOLOGY SYSTEMS ANALYSIS & TRADEOFF STUDIES Figure 2