The kinetics of nickel oxide reduction by hydrogen; measurements in a fluidized bed and in a gravimetric apparatus
- PDF / 1,744,362 Bytes
- 11 Pages / 603.28 x 783.28 pts Page_size
- 21 Downloads / 227 Views
P A P E R S on the r e d u c t i o n of nickel oxide p e l l e t s by h y d r o g e n a r e legion. However, d e s p i t e i t s i n d u s t r i a l s i g n i f i c a n c e , l i t t l e has b e e n p u b l i s h e d on the r e d u c t i o n of n i c k e l oxide i n fluidized b e d s . T h i s i s one r e a s o n why the r e s e a r c h d e s c r i b e d in t h i s p a p e r w a s u n d e r taken. A m o r e i m p o r t a n t r e a s o n w a s to t e s t the p r a c t i c a l i t y of u s i n g a l a b o r a t o r y fluidized bed for m e a s u r ing the r a t e s of g a s - s o l i d r e a c t i o n s , f r e e of e x t r a n e o u s e f f e c t s due to m a s s t r a n s f e r . A f i n a l objective of the r e s e a r c h was the g e n e r a t i o n of e x p e r i m e n t a l data for u s e in t e s t i n g m a t h e m a t i c a l m o d e l s f o r f l u i d i z e d bed r e a c t o r s . Such r e a c t o r s a r e widely used for the r o a s t ing of sulfide o r e s and, at l e a s t in c o u n t r i e s with a b u n dant s u p p l i e s of h y d r o c a r b o n s , show p r o m i s e of b e i n g a p r o f i t a b l e m e a n s of r e d u c i n g i r o n o r e s . It was decided to check the r e s u l t s of the fluidized bed e x p e r i m e n t s u s i n g the c o n v e n t i o n a l a p p a r a t u s in which the r a t e of r e a c t i o n is d e t e r m i n e d by m e a s u r i n g the weight change of a p e l l e t or c o m p a c t of solid a s it r e a c t s with a gas. The opportunity w a s t a k e n of i n v e s t i g a t i n g the effect of p e l l e t c o m p a c t i o n p r e s s u r e and g a s c o m p o s i t i o n on r e a c t i o n r a t e u s i n g the g r a v i m e t r i e apparatus. PREVIOUS INVESTIGATIONS The work d e s c r i b e d in this p a p e r f o r m s a p a r t of a c o n t i n u i n g i n v e s t i g a t i o n by the a u t h o r s and s e v e r a l w o r k e r s in other l a b o r a t o r i e s , a i m e d at r e l a t i n g the r a t e at which a p o r o u s solid u n d e r g o e s r e a c t i o n to the s t r u c t u r e of the solid; that is to such p a r a m e t e r s as the m e a n pore size, p o r o s i t y and specific s u r f a c e a r e a J. W. EVANS and S. SONG are Assistant Professor and PostDoctoral Student, respectively, Department of Materials Science and Engineering, University of California, Berkeley, CA 94720. C. E. LEON-SUCRE, formerly Graduate Student at Berkeley is now Assistant Professor, Escuela de lngenieria Mctalurgicay Ciencias de los Materiales, UniversidadCentral de Venezuela, Caracas, Venezuela. Manuscript submitted January 9, 1975. METALLURGICALTRANSACTIONS B
of the solid. The foundation of this r e s e a r c h was laid by the d e v e l o p m e n t of the " g r a i n m o d e l " by Szekely and E v a n s , ~-3 its g e n e r a l i z a t i o n by Sohn and Szekely 4 and the i n d e p e n d e n t d e v e l o p m e n t of s i m i l a r m o d e l s by T u r k d o g a n , 5 B i t s i a n e s , s Wen, v Pigford,8 Smith o and t h e i r c o w o r k e r s . The g r a i
Data Loading...
