Application of the levenspiel dispersion model to metal flow in pilot plant WORCRA continuous steelmaking furnace
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WORCRA c o n c e p t s is shown in F i g . 1. The p r o c e s s o p e r a t e s by the s e q u e n t i a l r e f i n i n g with oxygen l a n c e s of a s t r e a m of m o l t e n pig i r o n flowing f i r s t l y in a c i r c u l a r " b o w l " and then t h r o u g h a l a u n d e r . B a s i c flux is added n e a r the s l a g dam t o w a r d s the s t e e l outflow end. It g e n e r a t e s a highly b a s i c s l a g which flows count e r c u r r e n t to the m e t a l in the l a u n d e r s e c t i o n b e f o r e e m e r g i n g into a s l a g c l e a n - u p z o n e o r b r a n c h f r o m w h i c h it is c o n t i n u o u s l y tapped. Doubts had been c a s t a s to w h e t h e r a continuous s t e e l m a k i n g p r o c e s s would o p e r a t e s u c c e s s f u l l y u n l e s s the f u r n a c e w e r e v e r y long and m e t a l v e l o c i t i e s v e r y high. S z e k e l y 2 e s t i m a t e d a value of the d i s p e r s i o n group D / U L of 0.27 and i n d i c a t e d that at this l e v e l the c o n tinuous s t e e l m a k i n g f u r n a c e would b e h a v e as a s i n g l e s t i r r e d tank. S z e k e l y indicated that a p o s s i b l e solution to the p r o b l e m of longitudinal m i x i n g would be to u s e a s e r i e s of r e a c t o r s . Although c o n c e n t r a t i o n g r a d i e n t s down the length of the f u r n a c e had b e e n o b s e r v e d on a l l pilot plant WORCRA s t e e l m a k i n g t r i a l s , it w a s decided to d e t e r m i n e the m e t a l flow c h a r a c t e r i s t i c s by m e a n s of a tracer experiment. A p p r o x i m a t e l y l ~ l b of m o l t e n c o p p e r w e r e i n t r o duced into the feed l a u n d e r to the WORCRA s t e e l m a k i n g f u r n a c e . The point of i n t r o d u c t i o n w a s about 2 ft f r o m the f u r n a c e , F i g . 1, but as the m e t a l v e l o c i t y was high in the l a u n d e r , a p p r o x i m a t e l y 2 ft p e r s e c , the t r a c e r w a s a s s u m e d to r e p o r t i n s t a n t a n e o u s l y in the f u r n a c e . S a m p l e s of m e t a l f r o m the r e f i n e d s t e e l exit s t r e a m w e r e taken at a p p r o x i m a t e l y 1 min i n t e r v a l s f o r 45 m i n , a f t e r t r a c e r addition. T h e a c t u a l m e a n r e s i d e n c e t i m e of m e t a l is c a l c u lated f r o m t r a c e r data by:
w h e r e c is the c o n c e n t r a t i o n of t r a c e r at t i m e t a f t e r t r a c e r addition.
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Application of the Levenspiel Dispersion Model to Metal Flow in Pilot Plant WORCRA Continuous Steelmaking Furnace
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T. W. J E N K I N S , N. B. GRAY, AND H. K. W O R N E R T I - I E W O R C R A continuous s t e e l m a k i n g p r o c e s s has been d e s c r i b e d in a p r e v i o u s p a p e r . 1 The pilot plant u s e d at C o c k l e C r e e k , N. S. W., A u s t r a l i a , to t e s t the T. W. JENKINS is Senior Research Metall
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