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While-you-wait cholesterol removal
Patents Membrane
A
B
60 950 350 8
60 450 350 13
60 600 350 19.6
510 000
20 950
130 500
29
7365
Temperature, °C Feed pressure, psi Permeate pressure, psi Feed oil concentration, wt% Performance Flux, I/m2/day Oil rejection, %
Patent number: EP 4 8 9 5 7 3 Date: I0 J u n e 1992 Inventor: T.-J. C h e n Applicant: Exxon R e s e a r c h a n d E n g i n e e r i n g Co.
While-you-wait cholesterol removal A s e r i o u s p r o b l e m for m a n y people is a high level of cholesterol In their blood. The apparently lighthearted heading in fact i n d i c a t e s a r e a l n e e d for a n effective, selective p r o c e s s which c a n r e d u c e t h e level of low-density lipoprotein-cholesterol complex (LDL-C) in their blood w i t h o u t r e m o v i n g other beneficial c o m p o n e n t s . Modified diets, diet s u p p l e m e n t s or d r u g t h e r a p y a r e u s e d in m o s t c a s e s , b u t s o m e p a t i e n t s a r e either unwilling or u n a b l e to benefit from t h e s e treatments. There a r e p r o c e s s e s available w h i c h r e m o v e LDL-C directly from the blood, b u t t h e s e a r e n o t a perfect solution. If LDL-C levels in p l a s m a a r e lowered, either b y p l a s m a exchange, u l t r a f i l t r a t i o n b a s e d on m o l e c u l a r size, immunoadsorption, heparIn p r e c i p i t a t i o n or d e x t r a n s u l p h a t e a d s o r p t i o n , t h e s e t e c h n i q u e s also remove beneficial c o m p o n e n t s s u c h as h i g h - d e n s i t y l l p o p r o t e i n (HDL-C) from t h e p l a s m a . F u r t h e r m o r e , m o s t of the t e c h n i q u e s involve two steps: s e p a r a t i o n of t h e blood into cellular a n d p l a s m a c o m p o n e n t s , followed b y t r e a t m e n t of the p l a s m a a n d r e t u r n of t h e t r e a t e d p l a s m a a n d cells to t h e patient. This is t i m e - c o n s u m i n g a n d
10
B
involves m u c h h a n d l i n g of t h e various.blood components. A membrane holding an Immobfllzed affinity agent h a s b e e n developed which is c o m p a t i b l e with whole blood: this m a k e s it p o s s i b l e to speed u p the p r o c e s s a s well as m a k i n g the m e m b r a n e selective to LDL-C. The m e m b r a n e , in hollow-fibre form, is a p o l y s u l p h o n e - b a s e d polymer: the affinity agent is polyacrylic acid, which r e m o v e s negligible a m o u n t s of HDL or other blood proteins. The m e m b r a n e c a n be a u t o c l a v e d to sterilize it. In use, the p a t i e n t ' s blood is p a s s e d into a cartridge c o n t a i n i n g hollow fibres: the blood cells a r e r e t a i n e d by the m e m b r a n e while the p l a s m a c o m p o n e n t s p a s s t h r o u g h it. On the way t h r o u g h , LDL-C is c a p t u r e d a n d immobilized b y the polyacrylic acid. The blood cells a n d p l a s m a a r e r e c o m b i n e d at the cartridge exit a n d i m m e d i a t e l y r e t u r n e d to the patient. The cartridge c a n be r e g e n e r a t e d with a salt w a s h a n d reused.
Patent number: EP 488095 Date: 3 J u n e 1992 Inventors: M.E. P a r h a m , D.T. Nicholson, R.L. Duffy Applicant: W.R. Grace a n d Co.
Hydrogen manufacture The conventional p r o c e s s for m a k i n g b u l k q u a n t i t i e s of h y d r o g e n is the s t e a m 'reforming' of h y d r o c a r b o n s s u c h as n a t u r a l gas. The overall reaction, over a s u i t a b l e catalyst, is 2CH4+H20+
1/202
~
5H2+2CO
b u t t h e r e a c t i o n is e n d o t h e r m i c so a significant q u a n t i t y of m e t h a n e r e m a i n s unconverted. A similar reaction o c c u r s in a h e a t e d m e t h a n o l - s t e a m mixture: in either case the h y d r o g e n m u s t be s e p a r a t e d from the other r e a c t i o n p r o d u c t s a n d r e a c t a n t s . In the c o n v e n t i o n a l p r o c e s s the energy cost of doing this is considerable. Toyo Engineering p r o p o s e t h a t either r e a c t i o n b e c a r r i e d out in a r e a c t o r w h i c h h a s a c e n t r a l l y - p l a c e d cylindrical hydrogen-permeable membrane s u r r o u n d e d b y s t e a m reforming catalyst. As the r e a c t i o n proceeds, some product hydrogen c a n diffuse t h r o u g h the m e m b r a n e . This r e d u c e s the energy cost of the following steps. The r e a c t i o n s t a k e place at t e m p e r a t u r e s of several h u n d r e d d e g r e e s C, so it is not s u r p r i s i n g t h a t t h e m e m b r a n e m a t e r i a l is metallic p a l l a d i u m .
Patent numbers: JP 4182301, JP 4 1 8 2 3 0 2 Date: 29 J u n e 1992 Inventor: S. I i y a m a Applicant: Toyo Engineering Corporation
Potentially different membrane If it were p o s s i b l e to orient in a single d i r e c t i o n t h e polymer c h a i n s w h i c h go to m a k e u p the active layer of a typical composite m e m b r a n e , t h e n pore sizes would be l e s s v a r i a b l e a n d m e m b r a n e p e r f o r m a n c e would be improved. In t h i s invention, the s u p p o r t layer is c o a t e d with a b i f u n c t i o n a l r e a g e n t s u c h a s mor p - p h e n y l e n e d i a m i n e . Next a DC voltage is applied p e r p e n d i c u l a r to the s u r f a c e of the m e m b r a n e p r e c u r s o r , a n d a b i f u n c t i o n a l r e a g e n t which will r e a c t to form a p o l y m e r with the d i a m i n e is applied, still u n d e r the influence of the electrical field. The r e a g e n t s r e a c t a n d polymerize, giving c o n s i s t e n t l y oriented polymer chains. P e r m e a b i l i t y to l i q u i d s is high while solute rejection is also high.
M e m b r a n e T e c h n o l o g y No. 3 5
A
B
60 950 350 8
60 450 350 13
60 600 350 19.6
510 000
20 950
130 500
29
7365
Temperature, °C Feed pressure, psi Permeate pressure, psi Feed oil concentration, wt% Performance Flux, I/m2/day Oil rejection, %
Patent number: EP 4 8 9 5 7 3 Date: I0 J u n e 1992 Inventor: T.-J. C h e n Applicant: Exxon R e s e a r c h a n d E n g i n e e r i n g Co.
While-you-wait cholesterol removal A s e r i o u s p r o b l e m for m a n y people is a high level of cholesterol In their blood. The apparently lighthearted heading in fact i n d i c a t e s a r e a l n e e d for a n effective, selective p r o c e s s which c a n r e d u c e t h e level of low-density lipoprotein-cholesterol complex (LDL-C) in their blood w i t h o u t r e m o v i n g other beneficial c o m p o n e n t s . Modified diets, diet s u p p l e m e n t s or d r u g t h e r a p y a r e u s e d in m o s t c a s e s , b u t s o m e p a t i e n t s a r e either unwilling or u n a b l e to benefit from t h e s e treatments. There a r e p r o c e s s e s available w h i c h r e m o v e LDL-C directly from the blood, b u t t h e s e a r e n o t a perfect solution. If LDL-C levels in p l a s m a a r e lowered, either b y p l a s m a exchange, u l t r a f i l t r a t i o n b a s e d on m o l e c u l a r size, immunoadsorption, heparIn p r e c i p i t a t i o n or d e x t r a n s u l p h a t e a d s o r p t i o n , t h e s e t e c h n i q u e s also remove beneficial c o m p o n e n t s s u c h as h i g h - d e n s i t y l l p o p r o t e i n (HDL-C) from t h e p l a s m a . F u r t h e r m o r e , m o s t of the t e c h n i q u e s involve two steps: s e p a r a t i o n of t h e blood into cellular a n d p l a s m a c o m p o n e n t s , followed b y t r e a t m e n t of the p l a s m a a n d r e t u r n of t h e t r e a t e d p l a s m a a n d cells to t h e patient. This is t i m e - c o n s u m i n g a n d
10
B
involves m u c h h a n d l i n g of t h e various.blood components. A membrane holding an Immobfllzed affinity agent h a s b e e n developed which is c o m p a t i b l e with whole blood: this m a k e s it p o s s i b l e to speed u p the p r o c e s s a s well as m a k i n g the m e m b r a n e selective to LDL-C. The m e m b r a n e , in hollow-fibre form, is a p o l y s u l p h o n e - b a s e d polymer: the affinity agent is polyacrylic acid, which r e m o v e s negligible a m o u n t s of HDL or other blood proteins. The m e m b r a n e c a n be a u t o c l a v e d to sterilize it. In use, the p a t i e n t ' s blood is p a s s e d into a cartridge c o n t a i n i n g hollow fibres: the blood cells a r e r e t a i n e d by the m e m b r a n e while the p l a s m a c o m p o n e n t s p a s s t h r o u g h it. On the way t h r o u g h , LDL-C is c a p t u r e d a n d immobilized b y the polyacrylic acid. The blood cells a n d p l a s m a a r e r e c o m b i n e d at the cartridge exit a n d i m m e d i a t e l y r e t u r n e d to the patient. The cartridge c a n be r e g e n e r a t e d with a salt w a s h a n d reused.
Patent number: EP 488095 Date: 3 J u n e 1992 Inventors: M.E. P a r h a m , D.T. Nicholson, R.L. Duffy Applicant: W.R. Grace a n d Co.
Hydrogen manufacture The conventional p r o c e s s for m a k i n g b u l k q u a n t i t i e s of h y d r o g e n is the s t e a m 'reforming' of h y d r o c a r b o n s s u c h as n a t u r a l gas. The overall reaction, over a s u i t a b l e catalyst, is 2CH4+H20+
1/202
~
5H2+2CO
b u t t h e r e a c t i o n is e n d o t h e r m i c so a significant q u a n t i t y of m e t h a n e r e m a i n s unconverted. A similar reaction o c c u r s in a h e a t e d m e t h a n o l - s t e a m mixture: in either case the h y d r o g e n m u s t be s e p a r a t e d from the other r e a c t i o n p r o d u c t s a n d r e a c t a n t s . In the c o n v e n t i o n a l p r o c e s s the energy cost of doing this is considerable. Toyo Engineering p r o p o s e t h a t either r e a c t i o n b e c a r r i e d out in a r e a c t o r w h i c h h a s a c e n t r a l l y - p l a c e d cylindrical hydrogen-permeable membrane s u r r o u n d e d b y s t e a m reforming catalyst. As the r e a c t i o n proceeds, some product hydrogen c a n diffuse t h r o u g h the m e m b r a n e . This r e d u c e s the energy cost of the following steps. The r e a c t i o n s t a k e place at t e m p e r a t u r e s of several h u n d r e d d e g r e e s C, so it is not s u r p r i s i n g t h a t t h e m e m b r a n e m a t e r i a l is metallic p a l l a d i u m .
Patent numbers: JP 4182301, JP 4 1 8 2 3 0 2 Date: 29 J u n e 1992 Inventor: S. I i y a m a Applicant: Toyo Engineering Corporation
Potentially different membrane If it were p o s s i b l e to orient in a single d i r e c t i o n t h e polymer c h a i n s w h i c h go to m a k e u p the active layer of a typical composite m e m b r a n e , t h e n pore sizes would be l e s s v a r i a b l e a n d m e m b r a n e p e r f o r m a n c e would be improved. In t h i s invention, the s u p p o r t layer is c o a t e d with a b i f u n c t i o n a l r e a g e n t s u c h a s mor p - p h e n y l e n e d i a m i n e . Next a DC voltage is applied p e r p e n d i c u l a r to the s u r f a c e of the m e m b r a n e p r e c u r s o r , a n d a b i f u n c t i o n a l r e a g e n t which will r e a c t to form a p o l y m e r with the d i a m i n e is applied, still u n d e r the influence of the electrical field. The r e a g e n t s r e a c t a n d polymerize, giving c o n s i s t e n t l y oriented polymer chains. P e r m e a b i l i t y to l i q u i d s is high while solute rejection is also high.
M e m b r a n e T e c h n o l o g y No. 3 5