The formation and dissociation of magnesium alloy hydrides and their use for fuel storage in the hydrogen car
- PDF / 5,284,195 Bytes
- 11 Pages / 612 x 792 pts (letter) Page_size
- 28 Downloads / 152 Views
T H E p r i m a r y p r o b l e m c o n c e r n i n g the d e v e l o p m e n t of a h y d r o g e n - p o w e r e d c a r is the s t o r a g e of h y d r o g e n . In o r d e r to o b t a i n a r e a s o n a b l e c r u i s i n g r a n g e , e . g . , 300 m i l e s , about 30 Ibs of h y d r o g e n will be needed. S t o r a g e of t h i s a m o u n t of h y d r o g e n a s a gas is u n r e a s o n a b l e in view of t h e v o l u m i n o u s t a n k s r e q u i r e d . S t o r a g e a s a liquid is f e a s i b l e , n o t w i t h s t a n d i n g the fact t h a t a c r a s h p r o o f c r y o g e n i c tank would be r e q u i r e d , and i s p r e s e n t l y b e i n g i n v e s t i g a t e d at v a r i o u s l a b o r a t o r i e s . Howe v e r , the g r e a t e s t h y d r o g e n d e n s i t y p e r unit v o l u m e can be o b t a i n e d when h y d r o g e n is s t o r e d a s a m e t a l l i c h y d r i d e . The h y d r i d e s m a y be f o r m e d by r e a c t i o n of v a r i o u s m e t a l s o r i n t e r m e t a l l i c c o m p o u n d s with h i g h p r e s s u r e h y d r o g e n g a s at e l e v a t e d t e m p e r a t u r e s . Hyd r o g e n i s r e a d i l y d e l i v e r e d d u r i n g o p e r a t i o n of the v e h i c l e b y h e a t i n g the h y d r i d e to an e l e v a t e d t e m p e r a t u r e and m a i n t a i n i n g the h y d r o g e n p r e s s u r e below the e q u i l i b r i u m , d i s s o c i a t i o n p r e s s u r e . The h y d r i d e w i l l d i s s o c i a t e until t h e e q u i l i b r i u m p r e s s u r e is r e s t o r e d . If the s y s t e m p r e s s u r e is m a i n t a i n e d below the c r i t i c a l v a l u e , the h y d r i d e c o n t i n u o u s l y d i s s o c i a t e s until a l l of the h y d r i d e is gone. The m o s t p r e s s i n g q u e s t i o n p r e s e n t l y is which h y d r i d e should be used for the s t o r a g e s y s t e m . A n u m b e r of p a r a m e t e r s a r e involved, and the u l t i m a t e s e l e c t i o n wiI1 r e p r e s e n t a " t r a d e - o f f " b e t w e e n the v a r i ous p a r a m e t e r s . The f a c t o r s i n v o l v e d in the h y d r i d e selection are as follows: D. L. DOUGLASS is Professor of Engineering, School of Enginecring and Applied Science, Univcrsity of California, Los Angeles, CA 90024. Manuscript submitted February 13, 1975. METALLURGICAL TRANSACTIONS A
9 High H 2 p r e s s u r e at r e a s o n a b l e t e m p e r a t u r e s (low a b s o l u t e s t a b i l i t y ) 9 E x o t h e r m i c h e a t of f o r m a t i o n (low v a l u e ) 9 High H~ d e n s i t y p e r unit v o l u m e 9 Low m a s s d e n s i t y 9 Low c o s t 9 E a s e of f a b r i c a t i o n 9 R a p i d k i n e t i c s of f o r m a t i o n and d i s s o c i a t i o n 9 R e s i s t a n c e to e x t e n s i v e p a r t i c u l a t i o n . The f i r s t two f a c t o r s a r e t h e r m o d y n a m i c in n a t u r e and v e r y i m p o r t a n t . A l a r g e r e s e r v o i r of d a t a i n v o l v ing n u m e r o u s h y d r i d e s
Data Loading...
