Perspectives on the Economic Analysis of Ethanol Production from

10 Perspectives on the Economic Analysis of Ethanol Production from Biomass 1

Downloaded by MICHIGAN STATE UNIV on February 18, 2015 | http://pubs.acs.org Publication Date: January 29, 1981 | doi: 10.1021/bk-1981-0144.ch010

HARRY J. PREBLUDA and ROGER WILLIAMS, JR.

Roger Williams Technical And Economic Services, Incorporated, P.O. Box 426, Princeton, NJ 08540

Our objective is to clarify the many misapprehensions pertaining to the practical use of ethanol from biomass to extend motor fuel. While one might agree that biomass can be a renewable resource for non-polluting safe fuels, press reports have questioned the practicality of making large quantities of ethanol as a fuel source not only from rice, cereal grains or tuberous roots, but also from agricultural by-products, such as molasses, timber wastes, cheese whey, pineapple, waste paper or even garbage. From the many articles, there has appeared a potpourri of facts and fallacies (1,2). At all levels of our Federal and State Governments as well as within the automotive and petroleum industries, people have taken sides on the alcohol question. Opposing views are often voiced within the same organization. A leading university economics professor disagreed with the engineering department and questioned the feasibility of alcohol for transportation fuel (3). However, we want to take a neutral position and point out some of the pitfalls in the thinking on this subject. Large-scale usage may some day correct the present day economic inequities. This will come from new breakthroughs in fermentation and engineering technology to increase yields and reduce costs.

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0097-6156/81 /0144-0199$05.00/0 © 1981 American Chemical Society

In Biomass as a Nonfossil Fuel Source; Klass, D.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

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M o t o r Fuel A l c o h o l In 1 8 9 4 . Professor H a r t m a n at t h e Laboratory of t h e G e r m a n Distillery. D e u t s c h e n L a n d w i r t s h a f t s - G e s e l l s c h a f t . Leipzig. G e r m a n y , w a s a m o n g t h e first t o use a l c o h o l as a fuel in c o m p e t i t i o n t o p e t r o l e u m . In later years, scientists in o t h e r c o u n t r i e s f o u n d t h a t a l c o h o l / f u e l b l e n d s have s h o r t c o m ings. Storage t a n k m o i s t u r e c a n c o n t a m i n a t e t h e m i x t u r e so t h a t t h e r e is a l c o h o l a n d gasoline s e p a r a t i o n . Under c e r t a i n c o n d i t i o n s , i m p u r i t i e s in d e n a t u r i n g a g e n t s accelerate c o r r o s i o n . M e t h a n o l is a d é n a t u r a n t for e t h a n o l in m a n y c o u n t r i e s a n d usually c a n be used w i t h o u t i n t e r f e r i n g w i t h t h e effectiveness of fuel s y s t e m s . In s o m e parts of t h e w o r l d , i m p u r i t i e s in localarea gasoline c a n react w i t h small a m o u n t s of w a t e r in t h e a l c o h o l t o accelerate g a l v a n i c a c t i o n o n fuel s y s t e m s w i t h dissimilar metals. Henry Ford w a s o n c e q u e s t i o n e d as t o w h a t w o u l d h a p p e n t o his a u t o m o b i l e " b u g g y " business if p e t r o l e u m s u p p l i e s s h o u l d d w i n d l e . He said. " W e c a n g e t fuel f r o m f r u i t , f r o m t h a t of s u m a c by t h e roadside or f r o m apples, w e e d s , s a w d u s t — a l m o s t a n y t h i n g . There is fuel in every bit of v e g e t a b l e m a t t e r t h a t c a n be f e r m e n t e d . There is e n o u g h a l c o h o l in a year's yield of p o t a t o e s t o d r i v e t h e m a c h i n e r y necessary t o c u l t i v a t e t h e field for a h u n d r e d y e a r s . . . A n d it r e m a i n s for s o m e o n e t o f i n d h o w t h i s fuel can p r o d u c e d c o m m e r c i a l l y — b e t t e r fuel at a c h e a p e r price t h a n t h a t w e n o w k n o w . " Ford h o s t e d t h e Dearborn Conferences of A g r i c u l t u r e . I n d u s t r y a n d Science in t h e 1930's. This w a s t h e b e g i n n i n g of t h e Farm C h e m u r g i c C o u n c i l w h i c h p i o n e e r e d t h e use of r e n e w a b l e resources as i n d u s t r i a l r a w materials. F e r m e n t a t i o n a l c o h o l for m o t o r fuel w a s a major t o p i c at t h e Dearborn Conferences (4). A p l a n t at A t c h i s o n . Kansas soon f o l l o w e d in O c t o b e r 1 9 3 6 w i t h t h e first a t t e m p t t o m a r k e t an a l c o h o l / g a s o l i n e b l e n d in t h e U n i t e d States. D u r i n g 1 9 3 8 - 1 9 3 9 , t w e n t y m i l l i o n gallons of a l c o h o l / g a s o l i n e blends w e r e sold t h r o u g h i n d e p e n d e n t dealers a n d f a r m bureaus in t e n w e s t e r n a n d m i d w e s t e r n states (5). Nebraska alone had as m a n y as 2 5 0 dealers. A t a b o u t t h i s t i m e , A m e r i c a n a u t o makers w e r e s h i p p i n g vehicles a n d t r a c t o r s t o t h e Philippines w i t h special e n g i n e s d e s i g n e d t o use a l c o h o l f r o m s u g a r cane. T h i s e q u i p m e n t b e c a m e p o p u l a r in t h e Philippines w h e n gasoline prices w e r e too high. A u t o e n g i n e s b u r n i n g s t r a i g h t alcohols are p r o n e t o poor c o l d w e a t h e r s t a r t i n g . M u c h b a c k g r o u n d has been b u i l t u p for over 5 0 years on b o t h m e t h a n o l a n d e t h a n o l by r a c i n g car e n t h u s i a s t s u s i n g t h e s e b l e n d e d fuels in t h e i r special e n g i n e s (6,7). O n l y r e c e n t l y has t h e r e been serious t h o u g h t t o c h a n g i n g t h e d e s i g n of t h e a u t o m o b i l e e n g i n e for h a n d l i n g either m e t h a n o l or e t h a n o l . Prestart h e a t i n g of s o m e kind m a y have t o be used t o o v e r c o m e t h e s l u g g i s h p e r f o r m a n c e of special e n g i n e s for these fuels in c o l d climates.


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Gasohol in Brazil Currently. Brazil is leading t h e W o r l d in t r y i n g t o decrease d e p e n d e n c e o n i m p o r t e d fossil fuels. A b o l d g o v e r n m e n t p r o g r a m there centers a r o u n d t h e idea of c o n s t r u c t i n g 1 7 0 f e r m e n t a t i o n plants a n d distilleries. A f t e r w o r k i n g on a l c o h o l f o r over 5 0 years. Brazilian research h a d reached a standstill u n t i l t h e rise of oil prices in 1973. A l t h o u g h t h e e c o n o m i c s o n t h i s project are far f r o m favorable as y e t , Brazil is g o i n g f o r w a r d t o nationalize t h e " g a s o h o l " m o v e m e n t . T h e p o l i t i c i a n s in Brazil feel t h e i r f a r s i g h t e d n e s s s h o u l d p a y off w h e n oil prices g o u p . In t h e m e a n t i m e , t h e r e are m a n y n e w jobs f o r their u n e m p l o y e d . It s h o u l d be kept in m i n d t h a t Brazilian a l c o h o l cost w o u l d be m u c h h i g h e r if o u r U.S. w a g e scale w e r e used. Plans are also progressing in Brazil f o r intensive c u l t i v a t i o n of cassava (manioc). M o r e t h a n a dozen n e w a l c o h o l plants w i l l be b u i l t r e q u i r i n g cassava as a r a w material. This t u b e r o u s root can t h r i v e o n poor soil c o n d i t i o n s in Brazil w i t h l o w rainfall a n d is unlike cane since it c a n be harvested year r o u n d . Stillage b y - p r o d u c t f r o m m a n i o c c o u l d be used t o m a k e m e t h a n e or a h i g h p r o t e i n a n i m a l feed. Incidentally, cassava, b e i n g a p e r e n n i a l , c a n g r o w f o r several years w h i l e t h e roots a c c u m u l a t e starch. It differs f r o m sugar cane in t h a t cassava p r o c e s s i n g requires s o m e hydrolysis before f e r m e n t a t i o n . A l s o , sugar cane d e c o m p o s e s w h e n left in t h e fields t o o long. Because of starches a n d fibers, cassava is m o r e stable t o w e a t h e r i n g . It has n o t had m u c h o p p o r t u n i t y as y e t f o r g e n e t i c improvement. Brazilian officials have a p p a r e n t l y o v e r l o o k e d t h e possibility of using e t h a n o l or m e t h a n o l f o r c o n v e r s i o n t o h y d r o c a r b o n s s u c h as gasoline using t h e M o b i l process(8). This process c a n c o n v e r t e t h a n o l t o gasoline d i r e c t l y , t h u s a l l o w i n g t h e use of h y d r o c a r b o n fuel f r o m r e n e w a b l e resources in e x i s t i n g cars w i t h o u t e n g i n e m o d i f i c a t i o n . This s c h e m e w o u l d n o t require a separate ethyl alcohol/gasoline blend distribution system. Biomass N o t Complete Answer T h e o p i n i o n s of farmers, legislators a n d t h e p u b l i c o n t h e use of biomass f r o m a l c o h o l have been d e b a t e d a n d t h e oil c o m p a n i e s have had a d i f f i c u l t course t o steer(9). It is n o t generally realized t h a t oil c o m p a n i e s g e t into p r a c t i c a l l y all facets of energy. In a d d i t i o n t o coal a n d p e t r o l e u m d e v e l o p m e n t s , t h e y are in o t h e r activities s u c h as solar, w i n d , a t o m i c , tidal a n d r e n e w a b l e e n e r g y sources. They also w a n t t o k n o w h o w a l c o h o l can be best used as a source of energy. Some A m e r i c a n p e t r o l e u m c o m p a n i e s have taken a l o n g - r a n g e v i e w a n d m a d e b r e a k t h r o u g h s f o r h i g h a l c o h o l yields f r o m cellulosic w a s t e s using special f e r m e n t a t i o n technology.QO)


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The U.S. D e p a r t m e n t of Energy has been e v a l u a t i n g t h e pros a n d c o n s of a l c o h o l fuels (V\). DOE's m a i n c o n c l u s i o n has been t h a t b o t h e t h a n o l a n d m e t h a n o l can c o n t r i b u t e t o t h e e n e r g y resources of t h i s c o u n t r y by e x t e n d i n g l i q u i d fuel supplies. DOE appears t o be c o m m i t e d t o d e v e l o p i n g a l c o h o l fuel. If n a t i o n w i d e m a r k e t p e n e t r a t i o n of alcohol fuels takes place, present m a j o r fuel suppliers w i l l u n d o u b t e d l y have t o p a r t i c i p a t e . Over t h e long t e r m it is e x p e c t e d t h a t m e t h a n o l w i l l offer l o w e r cost possibilities t h a n e t h a n o l . A l t h o u g h t h e U.S. D e p a r t m e n t of A g r i c u l t u r e v i g o r o u s l y s u p p o r t s t h e d e v e l o p m e n t of g a s o h o l in t h e U.S.. it urges Congress t o be w a r y of proposals t h a t w o u l d c o m m i t h u g e a m o u n t s of U.S. feed grains t o gasohol (12). M e n t i o n s h o u l d be m a d e of o u r c o n c e r n a b o u t d i s t r i b u t i o n costs. T h e DOE p o s i t i o n papers gloss over d i s t r i b u t i o n costs of a l c o h o l / g a s o l i n e fuels. A l s o o v e r l o o k e d is t h e possible e c o n o m i c gain by g o i n g f r o m coal t o s y n t h e s i s gas t o m e t h a n o l t o gasoline u s i n g t h e M o b i l process for t h e latter route (8). This c o u l d a v o i d t h e p r o b l e m of n e w storage facilities a n d get a r o u n d t h e need for a n o t h e r fuel d i s t r i b u t i o n s y s t e m . Over 9 0 % of t h e present U.S.A. n o n - b e v e r a g e e t h y l a l c o h o l p r o d u c t i o n c o m e s f r o m p e t r o l e u m or n a t u r a l gas-derived e t h y l e n e synthesis. Less t h a n 1 0 % of t h e r e m a i n i n g a l c o h o l m a r k e t c o m e s f r o m f e r m e n t a t i o n of grains, f r u i t , a n d sulfite liquors. Using a r o u n d n u m b e r f i g u r e of 100 billion gallons of gasoline per year, t h e i n d u s t r i a l e t h a n o l p r o d u c t i o n in t h e U.S.A. a m o u n t s t o a b o u t o n e - t h i r d of one p e r c e n t of m o t o r fuel used by vehicles o n t h e h i g h w a y . It has been e s t i m a t e d t h a t if all t h e available f a r m l a n d w e r e used for g r o w i n g a g r i c u l t u r a l c r o p s in excess of t h o s e n e e d e d for f o o d p r o d u c t i o n , t h e e t h y l a l c o h o l p r o d u c e d f r o m these r e n e w a b l e crops a n d residues w o u l d m e e t o n l y 8 % of our nation's l i q u i d fuels e n e r g y needs for t r a n s p o r t a t i o n . Unless ethyl a l c o h o l f r o m b i o m a s s is subsidized for political reasons or for national s e c u r i t y purposes, it w i l l not be t h e fuel of c h o i c e t o be used in large q u a n t i t i e s (13,14). Of course, t h e r e w i l l be b r e a k t h r o u g h s in i m p r o v e d c r o p yields, processing t i m e a n d o t h e r e n e r g y savings. L i m i t e d use w i l l t a k e place in local g e o g r a p h i c areas w h e r e t h e f e r m e n t a t i o n of o f f - g r a d e grains t o e t h y l a l c o h o l can be s u p p o r t e d by s u b s i d y , tax c r e d i t s or loan guarantee. T h e U.S. has p l e n t y of c o r n i n v e n t o r y presently because of t h e e x c e l l e n t 1 9 7 8 c a r r y o v e r a n d i m p r o v e d o u t l o o k for t h e 1 9 7 9 crop. A t first g l a n c e , it appears t h a t a l c o h o l f r o m f e r m e n t e d g r a i n c o u l d leave us less d e p e n d e n t o n p e t r o l e u m supplies. Yet t h e r e are c a u t i o u s m e t e o r o l o g i s t s w h o e x p e c t t h e d r o u g h t c y c l e t o hit o u r c o u n t r y in t h e next f e w years. W e recall v i v i d l y t h e days of t h e d u s t s t o r m s a n d lack of rain in t h e corn belt. In a special U.S.D.A. report, it has been q u e s t i o n e d w h e t h e r w e c o u l d afford t o divert srzable q u a n t i t i e s of grain for m o t o r fuel purposes (1_3). It has been


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e s t i m a t e d t h a t s t a r t u p costs f o r plants a n d distilleries w o u l d be b e t w e e n $ 1 5 $ 1 7 billion f o r m a k i n g 1 0 0 billion gallons of gasohol b l e n d per year. This does not i n c l u d e a direct a d d e d s u b s i d y of $ 1 0 . 4 billion a year t o make t h e p r o d u c t c o m p e t i t i v e w i t h gasoline prices.


A n e w m e t h o d (15) f o r e x t r a c t i n g w h e a t g l u t e n offers s o m e possibilities f o r alcohol f e r m e n t a t i o n of w h e a t s t a r c h b y - p r o d u c t s in g e o g r a p h i c areas w h e r e this g r a i n w o u l d be a d v a n t a g e o u s . T h e n e w t e c h n o l o g y called t h e "Raisio A l f a - L a v a l " process is d e s c r i b e d as a " u n i q u e closed s y s t e m f o r w h e a t f r a c t i o n a t i o n s u b s t a n t i a l l y increasing t h e yield of h i g h q u a l i t y starch a n d vital g l u t e n w h i l e p e r m i t t i n g p o l l u t i o n - f r e e p r o c e s s i n g . " W i t h h i g h beef prices a h e a d , t h e w o r l d d e m a n d for g l u t e n in h u m a n f o o d is e x p e c t e d t o increase. Gasohol and t h e Beef Industry T h e beef p r o d u c e r s feel t h a t t h e gasohol d e v e l o p m e n t in t h e U.S. c o u l d h u r t its i n d u s t r y 0 6 ) . A n a t i o n w i d e gasohol p r o g r a m w o u l d b r i n g higher prices a n d h i g h e r p r o d u c t i o n costs t o be passed a l o n g t o c o n s u m e r s . There w o u l d be a n a d d i t i o n a l cost t o p r o d u c e r s in t h e f o r m of higher taxes t o p a y f o r t h e large g o v e r n m e n t subsidies n e e d e d f o r t h e gasohol p r o g r a m . T h e beef p r o d u c e r s are also w o r r i e d a b o u t regional livestock p r o d u c t i o n shifts. S t o c k m e n w o u l d t r y t o relocate near distilleries t o be close t o a l o w - c o s t source of b y - p r o d u c t feed. The greater feed use of distillers grains c o u l d s l o w d o w n t h e livestock cycle. U.S.D.A. researchers t h i n k t h a t t h e h i g h fiber value of distillers feed m i g h t require a longer d i g e s t i v e phase a n d t h u s push c o n s u m e r beef prices higher. Overall livestock p r o d u c t i o n w o u l d be e x p e c t e d t o decrease. A l s o t h e e x p e c t e d 10 billion g a l / y r subsidized alcohol m a r k e t w o u l d sharply increase feed prices a n d f o o d grains. Incidentally, w h e r e w o u l d t h e subsidies c o m e f r o m ? W h o w o u l d p a y f o r t h e m ? T h e 3 5 m i l l i o n t o n s of d r i e d distillers feed grains f r o m t h e gasohol p r o g r a m each year w o u l d depress soybean meal prices in s u c h a w a y t h a t there w o u l d be radical c h a n g e s in t h a t i n d u s t r y . T h e soybean c r u s h i n g i n d u s t r y f o r a n i m a l feed w o u l d be s u p p l a n t e d p r i m a r i l y b y o n e p r o d u c i n g f o o d oils a n d special p r o d u c t s i n t e n d e d f o r h u m a n use in t h e e x p o r t market. A n o t h e r w o r r y of beef p r o d u c e r s — w h a t w o u l d h a p p e n in t h e event of short U.S. f o o d crops? Also, is t h e r e e n o u g h c a p a c i t y f o r b o t h f o o d a n d gasohol p r o d u c t i o n ? W h a t is t h e real a n s w e r t o these q u e s t i o n s ? Land Program Possibility J a w e t z (1_7) presented a n i n t e r e s t i n g idea as a r e n e w a b l e resource r a w material p o t e n t i a l f o r e t h a n o l . It offers t h e f a r m e r a n o p p o r t u n i t y t o g r o w specific crops u s i n g t h e m i l l i o n s o f acres in t h e Federal G o v e r n m e n t " s e t


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a s i d e " p r o g r a m in e x c h a n g e for g u a r a n t e e d m i n i m u m prices of f a r m crops. Instead of leaving t h e land f a l l o w a n d idle. J a w e t z has s u g g e s t e d g r o w i n g a c r o p t h a t c o u l d be used by a distiller t o m a k e a l c o h o l . T h e s u b s i d y w o u l d revert t o t h e distiller. Ethanol based o n $ 2 . 0 0 / b u s h e l of c o r n w o u l d t h e n c o s t o n l y $ 0 . 4 5 / g a l at t h e distillery after a l l o w i n g t h e distiller a s u b s i d y c r e d i t of a p p r o x i m a t e l y $ 0 . 5 4 / g a l of e t h a n o l f r o m t h e " s e t a s i d e " p r o g r a m a n d


d i v e r t e d land. H o w e v e r , t h i s p r o g r a m m i g h t raise s o m e q u e s t i o n s b y c o n s e r v a t i o n i s t s . T h e y c o u l d c l a i m t h a t t h e c o n s t a n t p l a n t i n g of c r o p s o n land w o u l d have a t e n d e n c y t o run d o w n t h e soil unless there w a s heavy fertilization. W h i l e p o n d e r i n g a n s w e r s t o t h e s e q u e s t i o n s , let us e x a m i n e t h e possibilities of u s i n g o t h e r r a w materials s u c h as s u g a r c a n e or c a n e molasses f o r e t h a n o l p r o d u c t i o n . W e k n o w t h a t of t h e m a n y t y p e s of p l a n t material t h a t c a n be f e r m e n t e d , t h e greatest e n e r g y yield is o b t a i n e d w h e n sugar c a n e is f e r m e n t e d . T h e sugar cane p l a n t is c o n s i d e r e d t o be o n e of t h e m o s t e f f e c t i v e t o fix solar energy. If e t h a n o l is t o be m a d e f r o m a c a n e s o u r c e , it m u s t be p r o d u c e d in large q u a n t i t i e s f r o m available land t o m a k e it c o m p e t i t i v e a n d n o t have c o n s t r a i n t s w i t h o t h e r c o m p e t i n g crops. In t h e f u t u r e , t h e e c o n o m i c s c a n be i m p r o v e d by f e r m e n t i n g t h e h y d r o l y z e d bagasse fiber if it is n o t used d i r e c t l y as f u e l . It has also been s u g g e s t e d t h a t t o t a l f e r m e n t a b l e material in cane j u i c e be m a d e i n t o a l c o h o l w i t h o u t crystallizing sucrose. W h o l e Cane Process Rolz of G u a t e m a l a (1_8) r e p o r t e d o n t h e " E x - F e r m " process w h e r e b y e t h a n o l is f e r m e n t e d d i r e c t l y f r o m small pieces of w h o l e c h o p p e d cane. T h e a c c u m u l a t i o n of e t h y l a l c o h o l d u r i n g t h e f e r m e n t a t i o n leaches o u t o t h e r n o n sucrose c o m p o n e n t s a n d breaks d o w n t h e solid fibre m a t r i x of t h e cane. T h e s i m u l t a n e o u s e x t r a c t i o n a n d f e r m e n t a t i o n p r o v i d e s m a n y a d v a n t a g e s for t h e c a n e g r o w e r t o b e c o m e an a l c o h o l producer. Rolz p r o j e c t s a m a n u f a c t u r i n g c o s t of $ 0 . 6 4 3 / g a l of a l c o h o l vesus $ 0 . 7 9 5 / g a l for t h e c o n v e n t i o n a l s t a n d a r d t e c h n o l o g y e x c l u s i v e of c h a r g e s for return o n original i n v e s t m e n t . Sugar M a r k e t Implications V a c i l l a t i o n a n d m i s t r u s t in W a s h i n g t o n led t o t h e p l u m m e t i n g of s u g a r prices prior t o A u g u s t 1 9 7 8 . T h e c o m b i n a t i o n of record w o r l d s t o c k s of 3 0 m i l l i o n t o n s of sugar a n d l o w prices at t h e t i m e s t i m u l a t e d t h e t h i n k i n g of g o v e r n m e n t officials in c a n e - p r o d u c i n g , e n e r g y - b e l e a g u e r e d c o u n t r i e s t o be m o r e f a v o r a b l y d i s p o s e d t o m a k e a l c o h o l for fuel or gasohol p r o g r a m s . A n o t h e r f a c t o r has e n t e r e d t h e p i c t u r e for c o u n t r i e s basic in cane sugar a n d molasses p r o d u c t i o n . The large-scale d e v e l o p m e n t in t h e U.S. of h i g h


10.

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AND WILLIAMS


205

f r u c t o s e c o r n s y r u p (HFCS) u s i n g g l u c o s e isomerase t o prepare s w e e t e n e r s f r o m c o r n starch is h a v i n g a d r a m a t i c effect o n cane sugar markets. HFCS w i l l p r o b a b l y replace m o s t of t h e cane sugar w e n o w i m p o r t . H o w e v e r , it w i l l n o t replace t h e beet a n d cane sugar w e n o w g r o w in t h e U.S. Indirectly, t h i s w i l l release cane acreage especially in t h e d e v e l o p i n g n a t i o n s w h i c h i m p o r t p e t r o l e u m (gasoline). These n a t i o n s are n o w t h i n k i n g of a l c o h o l p r o d u c t i o n


f r o m their cane sugar or c a n e molasses. Currently, sugar p r o d u c t i o n is s h r i n k i n g in t h e U.S. T h e 1 9 7 9 c r o p is e x p e c t e d t o be d o w n b y as m u c h as 5 0 0 , 0 0 0 short t o n s a n d Congress is e x p e c t e d t o raise s u p p o r t prices. Attention t o By-Products Greater a t t e n t i o n is presently b e i n g g i v e n t o s o m e of t h e b y - p r o d u c t s of sugar processing a n d f e r m e n t a t i o n . W i t h rising fertilizer a n d labor costs, t h e sugar cane g r o w e r s in t h e State of Sao Paulo, Brazil have been r e t u r n i n g filter-press cake t o their g r o w i n g fields. Several mills have decreased usage of o r g a n i c fertilizers w h e n u s i n g filter-press cake. Brazilian e n v i r o n m e n t a l p r o t e c t i o n laws have recently p r o h i b i t e d a l c o h o l p r o d u c e r s f r o m d u m p i n g distillery slops or w a s t e s i n t o t h e rivers w h i c h t h e y have been d o i n g f o r s o m e t i m e . A p p l y i n g these w a s t e s t o t h e g r o w i n g fields a n d irrigation s y s t e m s is p r o v i n g beneficial. In Europe, b o t h beet a n d cane f e r m e n t a t i o n residues are e v a p o r a t e d t o a p p r o x i m a t e l y 6 5 % d r y m a t t e r a n d are referred t o as " v i n a s s e s " (19). W e s t e r n European p r o d u c t i o n of these materials in 1 9 7 8 w a s close t o 6 8 0 , 0 0 0 tons. A l c o h o l f e r m e n t a t i o n vinasses have been used in Europe f o r a n i m a l feed because of a p p e t i t e - s t i m u l a t i n g properties. There has also been a large-scale post-harvest use of vinasses o n fields. Prior t o W o r l d W a r II cane residues f r o m U.S. a l c o h o l f e r m e n t a t i o n w e r e i n c i n e r a t e d t o m a k e potash f o r fertilizer use. Both d u r i n g a n d after W o r l d W a r 11, m i l l i o n s of p o u n d s of d r y a n d also c o n d e n s e d molasses f e r m e n t a t i o n p r o d u c t s w e r e p r o f i t a b l y sold f o r speciality i n d u s t r i a l use o u t s i d e of t h e feed i n d u s t r y . These m a r k e t s have been n e g l e c t e d a n d c o u l d readily be established again o n a n e c o n o m i c basis t o r e d u c e overall e t h a n o l p r o d u c t i o n costs f r o m cane or beet molasses. In l o o k i n g at t h e fuel f a r m i n g p i c t u r e , one w o n d e r s j u s t h o w m u c h t i m e any of these processes c o u l d b u y in relation t o t h e life of o u r fossil fuel s u p p l y . Biomass c o n v e r s i o n t o fuel does n o t appear t o be a real i m m e d i a t e a n s w e r t o o u r l o n g - t e r m e n e r g y p r o b l e m because of t h e costs of t h e r a w m a t e r i a l ; nevertheless, s o m e b r e a k t h r o u g h s appear on t h e horizon. The need f o r a yearr o u n d s u p p l y o f r a w material necessitates u s i n g cellulose f r o m a g r i c u l t u r a l , forest or m u n i c i p a l solid w a s t e s as t h e f e e d s t o c k source. T h e h i g h cost of e t h a n o l f r o m grain or sugar c a n e is d u e p r i m a r i l y t o r a w material w h i c h


206

BIOMASS

AS A

NONFOSSIL

FUEL

SOURCE

represents a b o u t t w o - t h i r d s of alcohol p r o d u c t i o n costs. In t h e U.S., t h e r e are t r e m e n d o u s t o n n a g e s of cellulosic materials d e r i v e d f r o m various u r b a n a n d industrial o r g a n i c w a s t e s w h i c h can be o b t a i n e d at l o w cost. T o use t h i s b i o m a s s for f e r m e n t a t i o n , it is m o s t i m p o r t a n t t o have it c o l l e c t e d a n d available at a c e n t r a l l o c a t i o n . Biomass e n t h u s i a s t s o f t e n overlook t h e h i g h cost of b r i n g i n g these t y p e s of r a w materials t o t h e p r o d u c t i o n plant.


Process Possibilities S i g n i f i c a n t b r e a k t h r o u g h s have recently t a k e n place w h i c h w i l l i m p r o v e t h e e c o n o m i c p i c t u r e for m a k i n g a l c o h o l f r o m solid w a s t e . Rutgers U n i v e r s i t y research (20) o n t h e r m o t o l e r a n t m u t a n t strains of o r g a n i s m s p r o d u c i n g cellulase of a h i g h e r order t h a n r e p o r t e d heretofore s h o u l d be m e n t i o n e d . I m p o r t a n t w o r k o n v a c u u m t e c h n o l o g y t o o v e r c o m e factors of a l c o h o l i n h i b i t i o n l i m i t i n g f e r m e n t a t i o n e f f i c i e n c y has b e e n r e p o r t e d by Cysewski a n d W i l k e (21) as w e l l as R a m a l i n g h a m a n d Finn (22). Cysewski a n d W i l k e s u g g e s t e d s o m e process d e s i g n f e r m e n t a t i o n s c h e m e s for c o n t i n u o u s cell recycle a n d also v a c u u m f e r m e n t a t i o n processes for m a k i n g 7 5 , 0 0 0 gallons of 9 5 % e t h a n o l / d a y . Using a reasonable yeast b y p r o d u c t credit of $ 0 . 1 0 / l b , their net e s t i m a t e d p r o d u c t i o n cost appeared t o be $ 0 . 8 2 3 / g a l for t h e c o n t i n u o u s cell recycle s y s t e m as c o m p a r e d t o $ 0 . 8 0 6 / g a l for t h e v a c u u m f e r m e n t a t i o n . This c o m p a r e s f a v o r a b l y w i t h t h e c u r r e n t price of s y n t h e t i c 9 5 % e t h a n o l selling a r o u n d $ 1 . 4 0 / g a l . Spano (23) at t h e U.S. A r m y Laboratories has reassessed t h e e c o n o m i c s of cellulose process t e c h n o l o g y for p r o d u c t i o n of e t h a n o l using u r b a n w a s t e as a cellulosic substrate. T h e results of t h i s s t u d y are e n c o u r a g i n g . W i t h i m p o v e d cellulose p r o d u c t i v i t y a n d b y - p r o d u c t c r e d i t s of $ 0 . 5 4 / g a l of e t h a n o l , S p a n o has been able t o get t h e l o w e s t e s t i m a t e d cost d o w n t o $ 0 . 8 9 / g a l of 9 5 % e t h a n o l using a unit cost of $ 0 . 1 1 / g a l of a l c o h o l for t h e cellulosic material. Hoge (24) has s u g g e s t e d a novel e t h a n o l process u s i n g steam-sterilized i m p u r e cellulosic f r a c t i o n s of solid m u n i c i p a l w a s t e s t r e a t e d w i t h a m i x t u r e of e n z y m e a n d yeasts. T h e c o m b i n e d e n z y m a t i c d i g e s t i o n of cellulose t o sugars a n d t h e f e r m e n t a t i o n of sugars t o alcohol takes place in a c o m m o n reaction vessel. T h e s y s t e m has several reactors o p e r a t i n g at a t m o s p h e r i c pressure. Each reactor is i n t e r m i t t e n t l y c o n n e c t e d t o a shared r e c i r c u l a t i o n s y s t e m h a v i n g a flash c h a m b e r f r o m w h i c h a l c o h o l is d i s t i l l e d f r o m t h e reaction mass. T h e reaction t e m p e r a t u r e of t h e f e r m e n t a t i o n is also c o n t r o l l e d b y t h e v a c u u m . The u n i q u e d e s i g n of t h i s process e x t e n d s t h e life of t h e e n z y m e a n d reduces cost. Repeated reuse of t h e e n z y m e also makes t h e process


10.

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AND WILLIAMS


207


a t t r a c t i v e . Enzyme cost has been h o l d i n g back c o m m e r c i a l - s c a l e cellulose d i g e s t i o n . Ethanol cost in t h e Hoge process is e s t i m a t e d a r o u n d $ 0 . 4 0 / g a l , exclusive of selling expenses, a d m i n i s t r a t i v e costs and profits based u p o n an a n n u a l p r o d u c t i o n of 32.7 m i l l i o n gallons of e t h a n o l . Recent u n p u b l i s h e d data f r o m Cornell University s h o w e d t h a t v a c u u m removal of alcohol f r o m t h e Hoge process i m p r o v e d yields per unit of cellulase e n z y m e used. A n o t h e r n o t e w o r t h y d e v e l o p m e n t is g o i n g o n at Purdue University. A c o m b i n a t i o n of solvent p r e t r e a t m e n t a n d e n z y m e hydrolysis of cellulose is used t o o b t a i n a very h i g h yield of sugar f o r t h e p r o d u c t i o n of alcohol (25). This opens great o p p o r t u n i t i e s f o r m a k i n g use of t h e o n e billion t o n s of cellulosic residues available each year f r o m cornstalks, w h e a t s t r a w , sugar mill bagasse, s a w m i l l rejects, p a c k a g i n g residues, l o g g i n g residues, a n i m a l feedlot w a s t e s , c i t y t r a s h , e t c . There is no q u e s t i o n t h a t t h e d i m i n i s h i n g supplies of o u r n o n - r e n e w a b l e materials w i l l a c c e n t u a t e t h e d e m a n d f o r resources t h a t are r e n e w a b l e . W e s h o u l d be practical in o u r t h i n k i n g . Let us r e m e m b e r t h a t if a / / t h e c o r n g r o w n in t h e W o r l d a n d a / / t h e w h e a t a n d all t h e o t h e r w o r l d crops g r o w n b y farmers w e r e t o be c o n v e r t e d into a l c o h o l , it w o u l d be six t o seven p e r c e n t of t h e e n e r g y e q u i v a l e n t of t h e w o r l d c r u d e oil p r o d u c t i o n (Table I). The c a l c u l a t i o n s in Table I are based o n t h e a s s u m p t i o n t h a t u p o n f e r m e n t a t i o n , a p p r o x i m a t e l y half t h e energy of grain is c o n v e r t e d t o e t h a n o l . This is exclusive of natural gas or coal e n e r g y sources. The idea of r e n e w a b l e s o u n d s great u n t i l y o u p u t it into perspective a n d look at t h e e c o n o m i c s (Table II). M o s t ecologists j u s t d o n ' t . The e c o n o m i c d i s p a r i t y of f e r m e n t a t i o n alcohol as fuel at t h e service s t a t i o n p u m p c o m p a r e d t o gasoline at t o d a y ' s prices of a r o u n d $ 1 . 0 0 / g a l is self-evident w i t h o u t even g o i n g into Btu or p e r f o r m a n c e ratings. Yet in t h e m i d s t of t h i s p e s s i m i s m , t h e r e is s o m e h o p e t o at least make use of industrial a n d u r b a n w a s t e material t o e x t e n d o u r fuel supplies (26). W e feel t h a t o u r greatest o p p o r t u n i t i e s m a y y e t c o m e f r o m b r e a k t h r o u g h s i n v o l v i n g t h e cross d i s c i p l i n e s b e t w e e n t h e c h e m i s t , engineer, a g r i c u l t u r a l engineer, m i c r o b i o l o g i s t , g e n e t i c i s t , b i o c h e m i s t , a g r o n o m i s t a n d last b u t n o t least, t h e economist A s W i n s t o n Churchill o n c e said. " W e have n o t reached t h e b e g i n n i n g of t h e e n d . b u t perhaps w e have reached t h e e n d of t h e b e g i n n i n g . "


208

BIOMASS

AS A

NONFOSSIL

FUEL

SOURCE

T a b l e I. A N N U A L W O R L D G R A I N S U P P L Y A L C O H O L E Q U I V A L E N C E A N D CRUDE OIL USE

CRUDE OIL

1975

19.5x10


5.8X10 Total

6

barrels

9

Btu/barrel

113.1 X 1 0

Btu's

1 5

113.1 Q u a d s CORN

1975

3 2 4 . 7 2 1 . 0 0 0 m e t r i c t o n s ( 3 5 8 x 1 0 short tons) 380 Kcal/100 grams 6859 Btu/lb

WHEAT

1975

3 5 5 . 9 8 5 . 0 0 0 m e t r i c t o n s ( 3 9 2 x 1 0 short tons)

6

6

330 Kcal/100 grams RICE

1975

SOYBEAN

1975

5957 Btu/lb

348,374.000 metric tons ( 3 8 4 x 1 0

6

s h o r t tons)

370 Kcal/100 grams

6679 Btu/lb

68.900.000 metric tons

(76 Χ 1 0

360 Kcal/100 grams

6498 Btu/lb

Btu .25198 K i l o g r a m - c a l o r i e Pounds — 4 5 4 grams

6

short tons)

3.97 B t u / . 2 2 lbs. 18.05 B t u / l b

CORN

716x10

9

Ibs.x6.859x10 - 4 . 9 X 1 0

WHEAT

784X10

9

Ibs.x5.957x10 = 4.7X10

1 5

Btu's = 4.7 q u a d s

RICE

768X10

9

Ibs.x6.679x10 = 5.1x10

1 5

Btu's =

5.1 q u a d s

SOYBEAN 152X10

9

Ibs.x6.498x10 -

1 5

Btu's-

.9 q u a d s

3

3

3

3

.9x10

1 5

Btu's

- 4.9 q u a d s

15.6 q u a d s

15.6x0.50 2J*

7.8 q u a d s -

a l c o h o l e q u i v a l e n t of W O R L D GRAINS

= 6.9% of CRUDE OIL USE



10.

PREBLUDA

A N D WILLIAMS

209


Table I I . F E R M E N T A T I O N E T H A N O L A S FUEL

Φ/QAL

CORN

WOOD WASTE

SUGAR CANE

CASSAVA

56 20 30

68 33 36

Net R a w M a t e r i a l Cost Processing Cost

44 30

Capital Charges

40

68 40 82

114

190

106

137

5 8

5 8

5 8

5 8

127

203

119

150

SUB-TOTAL Distribution Dealer M a r g i n PUMP PRICE ( e x c l u d i n g taxes)


210

BIOMASS AS A NONFOSSIL FUEL SOURCE


REFERENCES

1.

Anderson J. "Gasohol Gasohowl", NY. Daily News. July 5, 1978.

2.

Klass, D. L. "Symposium Papers", Energy from Biomass and Wastes Symposium sponsored by the Institute of Gas Technology, Washington, D.C., Aug 1978; Institute of Gas Technology: Chicago, 1978.

3.

Anderson, Ε. V. Chem. Eng. 1978,

4.

Reese, Κ. M. Chem. Eng. News 1979, 57 (35), 56.

56 (31), 8-12, 15.

5. Hind, J. D. Chem. Eng. News 1978, 56 (35), 43. 6. Williams, Roger, Jr. "Methanol — The Energy Chemical", presented to the World Trade Institute and Chemurgic Council on Renewable Resources, New York, May 1976. 7. Williams, Roger, Jr. "Methanol — Markets vs. Price". Testimony before State Affairs Committee, Alaska State Senate, Juneau, Alaska, 1976. 8. Smay, V. E. Popular Science 1978, June, pp 90-91; Weisz. P. B.; Marshall, J. F. "High Grade Fuels From Biomass — Analysis of Potentials and Constraints". International Symposium On Energy and Technology, International Association of Science and Technology for Development (I.A.S.T.E.D.), Montreux, Switzerland, June 19-21, 1979; Weisz, P. B.; Marshall, J. F. "Fuels From Biomass: A Critical Analysis of Technology & Economics"; Marcel Dekker: New York City, in press. 9. Pratt, H. T. Chem. Eng. News 1978, 56 (41), 2,55. 10. Gauss, William F.; Suzuki, S.; Takagi, M. U.S. Patent 3990944, 1976; Huff, George F.; Yata, N. U.S. Patent 3990945, 1976; Chemical Marketing Reporter 1979, 216 (8), 7. 11.

United States Department of Energy, "Position Paper on Alcohol Fuels", March 1978; United States Department of Energy, "The Report of the Alcohol Fuels Policy Review", June 1979.

12.

Milling and Baking News 1979, 58 (28), 59.


10. PREBLUDA AND WILLIAMS Economics of Ethanol Production 211

13.

United States Department of Agriculture, Economics, Statistics & Cooperatives Service, "Gasohol From Grain ... The Economic Issues". Prepared for the Task Force on Physical Resources, Committee of The Budget, U.S. House of Representatives, Washington, D.C., January 19, 1978.

14. Klosterman, H.J.; Banasik, O. J.; Buchanan, M. L.; Taylor, F. R.; Harrold, R. L. Farm Res. 1978, 35 (2), 3-8. Downloaded by MICHIGAN STATE UNIV on February 18, 2015 | http://pubs.acs.org Publication Date: January 29, 1981 | doi: 10.1021/bk-1981-0144.ch010

15.

Kerkkonen, H. K.; Laine, Κ. M. J.; Alanen, M. R.; Renner, H. V. U.S. Patent 3951938, 1976.

16. Richter, J. Beef 1978, 72. 17. Jawetz, P. "Symposium Papers", Energy From Biomass and Wastes Symposium sponsored by the Institute of Gas Technology, Washington, D.C., Aug 1978; Institute of Gas Technology: Chicago, 1978; 14th InterSociety Energy Conversion Engineering Conference, Boston, Mass. Aug 1979; American Chemical Society, Division of Petroleum Chemistry, Washington, D.C., September, 1979. 18. Rolz, C. Meeting of the American Chemical Society, Miami, September 1978. American Chemical Society: Washington, D.C., 1978. 19. Lewicki, W.Process Biochemistry 1978, 78 (13), 12. 20.

Montenecourt, B. S.; Eveleigh, D. E. "Hypercellulolytic Mutants and Their Role in Saccharification"; Rensselaer Polytechnic Institute; Troy, N.Y., June 20-21, 1978.

21.

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RECEIVED JUNE 18, 1980.


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