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Gas cleaning system
Patents
Patents This is a list of r e c e n t l y p u b l i s h e d patents covering designs a n d i n v e n t i o n s of r e l e v a n c e to s y n t h e t i c m e m b r a n e technology. W h e r e t h e s a m e device h a s b e e n p a t e n t e d i n s e v e r a l c o u n t r i e s , we n o r m a l l y give t h e B r i t i s h p a t e n t n u m b e r . If t h e r e is n o UK p a t e n t , we give t h e n u m b e r of a n E n g l i s h - l a n g u a g e p a t e n t , if o n e exists. The p a t e n t s list is c o m p i l e d from i n t e r n a t i o n a l s o u r c e s b y BHR G r o u p ' s i n f o r m a t i o n service. The facility c a n also b e u s e d to carry out retrospective patent s e a r c h e s - - to test t h e validity, n o v e l t y or i n f r i n g e m e n t of e x i s t i n g p a t e n t s or n e w ideas. BHR G r o u p , Cranfield, Bedford MK43 0AJ, UK, will p r o v i d e free estimates on request. C o u n t r i e s c a n b e identified b y the code in f r o n t of t h e n u m b e r a s follows: AT A u s t r i a AU A u s t r a l i a BE B e l g i u m BR Brazil CH S w i t z e r l a n d DD E a s t G e r m a n y DE West G e r m a n y DK D e n m a r k EP E u r o p e a n P a t e n t E S S p a i n FI F i n l a n d FR F r a n c e GB B r i t a i n HU H u n g a r y IL Israel IR Eire IT Italy JP Japan KP North Korea LI L i e c h t e n s t e i n LU L u x e m b o u r g NL N e t h e r l a n d s NO Norway RO R o m a n i a SE S w e d e n US U n i t e d S t a t e s SU Soviet U n i o n WO World P a t e n t (Patent Treaty Cooperation publication) BHR G r o u p does n o t o p e r a t e a d o c u m e n t delivery service for p a t e n t s , b u t full copies of t h e o r i g i n a l p a t e n t d o c u m e n t s c a n be o b t a i n e d from t h e following addresses: The B r i t i s h L i b r a r y P a t e n t E x p r e s s 25 S o u t h a m p t o n B u i l d i n g s L o n d o n WC2A lAW, UK Fax: 071 3 2 3 7 2 3 0 (The B r i t i s h L i b r a r y will also s u p p l y a list of UK l i b r a r i e s included in the Patent I n f o r m a t i o n Network.) US P a t e n t Office
M e m b r a n e T e c h n o l o g y No. 4 0
Scientific L i b r a r y 15th a n d E a s t Streets, NW W a s h i n g t o n , DC 2 0 2 3 l, USA The J a p a n e s e P a t e n t Office 4-3 Kaksumigaseki 3-chome C h i y o d a - k u , Tokyo 100, J a p a n
Fluorine t r e a t m e n t for membrane A p a t e n t i n t h e l a s t i s s u e referred to c h l o r i n e t o l e r a n c e i n m e m b r a n e s , a n d to relatively low c o n c e n t r a t i o n s at that. This p a t e n t d e s c r i b e s the u s e of a 0.025-2% fluorine-in-helium m i x t u r e , followed b y air oxidation, to i m p r o v e the p r o p e r t i e s of a polysulphone membrane.The a p p l i c a t i o n of t h e t r e a t e d m e m b r a n e is i n p r o t e i n r e m o v a l from a q u e o u s s o l u t i o n s , a t a s k r e q u i r i n g r e s i s t a n c e to fouling. The initial m a t e r i a l h a s a pore size of 0 . 0 0 1 - 1 0 m i c r o n , i.e. it c a n b e s u i t a b l e for microffltration, u l t r a f i l t r a t i o n or r e v e r s e o s m o s i s . T h e pore size is not substantially altered by the t r e a t m e n t . The m e c h a n i s m at t h e m o l e c u l a r scale a p p e a r s to be t h e f o r m a t i o n of -CHF- g r o u p s a t the s u r f a c e of the m e m b r a n e . T h e s e m o d i f y the h y d r o p h i l i c t y of the m e m b r a n e surface without affecting the pores.
Patent number: US 5 1 5 1 1 8 3 Date: 29 S e p t e m b e r 1992 Inventors: R.H. S e d a t h , D.R. Taylor, L.S. White Applicant: Allied-Signal Inc.
Hollow-fibre polyvinylpyrrolidone u s e This E u r o p e a n P a t e n t from a J a p a n e s e c o m p m l y offers a n e w m o d i f i c a t i o n of the h y d r o p h o b l c n a t u r e of p o l y s u l p h o n e r e s i n s . V a r i o u s h y d r o p h i l i c m a t e r i a l s are incorporated in these p o l y s u l p h o n e s , often to allow w e t t i n g of the s u r f a c e to t a k e
place, s o m e t i m e s b e i n g lost from t h e m e m b r a n e via leaching. This p r o c e s s fixes a hydrophilic material in the polymer matrix by cross-llnking so t h a t it c a n n o t l e a c h out. The c h o s e n c o m p o u n d is polyvinylpyrrolidone: the chosen m e t h o d is to s p i n a hollow fibre from a s o l u t i o n c o n t a i n i n g t h e polysulphone a n d the p o l y v i n y l p y r r o l i d o n e , k e e p it w e t t e d a s a hydrogel, a n d c r o s s l i n k it u s i n g g a m m a radiation.
Patent number: EP 5 0 9 6 6 3 Date: 21 O c t o b e r 1992 Inventors: T. K o b a y a s h i , K. Tanaka Applicant: T o r a y I n d u s t r i e s Inc.
Gas c l e a n i n g system H y d r o g e n s u l p h i d e is a c o m m o n c o n s t i t u e n t of n a t u r a l g a s a n d of g e o t h e r m a l s t e a m . It is n o t d e s i r a b l e for t h e H2S to r e m a i n i n t h e n a t u r a l gas, n o r c a n it b e v e n t e d from g e o t h e r m a l e n e r g y plants. There are several w e l l - e s t a b l i s h e d m e t h o d s for r e m o v i n g t h e H2S; m o s t involve d i s s o l v i n g t h e acidic c o m p o n e n t s of t h e n a t u r a l gas i n a s o l v e n t containing a base such as p o t a s s i u m c a r b o n a t e or a n e t h a n o l a m i n e . The s o l v e n t is h e a t e d to r e l e a s e t h e H2S, w h i c h is t h e n u s u a l l y c o n v e r t e d to elemental s u l p h u r in a controlled-oxidation gas-phase process. T h a t s e q u e n c e of e v e n t s is m o s t effective w h e n H2S c o n c e n t r a t i o n s a r e h i g h or a large v o l u m e of gas is c l e a n e d . W h e n the r e v e r s e is t r u e , it is c h e a p e r a n d / or m o r e c o n v e n i e n t to operate a process which captures a n d oxidizes t h e H2S i n a single step. Such processes have been a v a i l a b l e for t h r e e d e c a d e s , m o s t l y u s i n g c h e l a t e d i r o n or v a n a d i u m c o m p o u n d s which are e a s i l y r e d u c e d from ferric to f e r r o u s or from V[V] to V[III] b y t h e H2S (which is oxidized to produce sulphur), and then can
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Patents b e reoxidized i n air. The c h e l a t i n g a g e n t is n i t r i l o t r i a c e t i c acid or EDTA. The s o l u t i o n c a n t h e n b e recycled to the g a s c l e a n i n g u n i t . The s u l p h u r is filtered from t h e s o l u t i o n a n d is of c o m m e r c i a l quality. As w i t h m a n y g a s c l e a n i n g processes involving scrubbing solutions, the f u n d a m e n t a l r e a c t i o n is n o t t h e o n l y o n e to t a k e place, a n d it is n e c e s s a r y to eliminate byproducts a n d chelate d e g r a d a t i o n c o m p o u n d s so t h a t t h e gas c l e a n i n g p r o c e s s r e m a i n s effective. T h i s is m o s t easily achieved by bleeding the system a n d r e p l e n i s h i n g w i t h f r e s h active agent. The p a t e n t r e d u c e s l o s s e s of the iron/chelate c o m p o u n d by adding a n extra nanofiltration s t e p after t h e s u l p h u r is r e m o v e d . The m e m b r a n e allows w a t e r a n d s o l u t e s w i t h a m o l e c u l a r weight below a b o u t 225 to p a s s t h r o u g h , b u t r e t a i n s t h e chelate. I n t h i s way impurities and degradation p r o d u c t s are r e m o v e d w i t h o u t loss of t h e active i n g r e d i e n t .
P a t e n t n u m b e r : WO 9 2 1 7 4 0 1 Date: 15 O c t o b e r 1992 Inventors: J.G. G r i e r s o n , M.C. Alien Applicant: Dow C h e m i c a l Co
Soya milk preparation Tofu, or s o y a b e a n c u r d , is m a d e b y h e a t i n g t h e l i q u i d from s t e e p i n g g r o u n d soya b e a n s i n water. T h i s 'soya m i l k ' is traditionally made by grinding a n d steeping the soya beans, t h e n filtering t h e m i x t u r e after the b e a n s h a v e first b e e n s o a k e d i n a c h a n g e of w a t e r for s o m e time. If t h e s o a k i n g s t e p is o m i t t e d t h e n the m i l k a n d c u r d h a v e a h a r s h t a s t e a n d smell; t h i s is c a u s e d b y the a c t i o n of a s o l u b l e e n z y m e which the soaking step leaches o u t of t h e b e a n s . The p a t e n t from K i k k o m a n ( p r o b a b l y k n o w n i n t h e West a s a soy s a u c e m a n u f a c t u r e r ) s h o r t e n s the p r o c e s s i n g t i m e b y o m i t t i n g the s o a k i n g s t e p a n d b y u s i n g a n ultraffltration m e m b r a n e between
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the s t e e p i n g a n d c o a r s e f i l t r a t i o n steps. The m e m b r a n e r e t a i n s high-molecnlar-weight c o m p o u n d s from the b e a n milk, s u c h a s p r o t e i n s , while allowing carbohydrates s u c h as o l i g o s a c c h a r i d e s to p a s s t h r o u g h . R e m o v i n g o l i g o s a c c h a r i d e s from p u l s e s or t h e i r p r o c e s s e d products has an incidental d o u b l e olfactory benefit: t h e b e a n c u r d fiavour is i m p r o v e d a s m e n t i o n e d earlier, a n d the i n c i d e n c e of digestive t r a c t f l a t u s ( c a u s e d w h e n g u t b a c t e r i a digest oligosaccharides and produce m e t h a n e ) is d i m i n i s h e d .
n u t r i e n t s w h i c h w o u l d allow b a c t e r i a or m o u l d s to prosper. The d o u b l e b o n d s p r e s e n t i n a l m o s t all vegetable otis are oxidized w h e n i n c o n t a c t with the air or dissolved oxygen, f o r m i n g l o n g - c h a i n fatty a c i d s w h i c h give the c h a r a c t e r i s t i c r a n c i d smell. D a i n i p p o n c l a i m t h e u s e of a deoxygenating membrane -poly-4-methylpent-l-ene -- which is p e r m e a b l e to oxygen dissolved i n t h e oil. If t h e oxygen c o n t e n t is lowered to 0 . 5 - 2 . 0 p p m t h e n the k e e p i n g q u a l i t i e s of the oil will be improved.
P a t e n t number: J P 4 2 9 9 9 5 2 Date: 23 October 1992 Inventor: N. Horie Applicant: K i k k o m a n Corp
P a t e n t number: J P 4 2 9 0 5 0 2 Date: 15 O c t o b e r 1992 Inventor: K. K u r i y a m a Applicant: D a i n i p p o n I n k & C h e m i c a l Inc
Solvent resistant membrane The s o l v e n t s to be r e s i s t e d are halogen-substituted hydrocarbons; the m e m b r a n e m a t e r i a l is a polyimide; the m e a n s of i n t r o d u c i n g r e s i s t a n c e is to r e a c t o x y p h t h a l i c acid a n h y d r i d e or a derivative with a diamine which contains a p r o p o r t i o n of a d i a m i n o s f l o x a n e . I n the m e m b r a n e the s i l i c o n / c a r b o n ratio at the s u r f a c e is greater t h a n the t h e o r e t i c a l o n e c a l c u l a t e d from the m o l e c u l a r s t r u c t u r e of the polymer, while c o n f o r m i n g to t h e o r y i n the b o d y of t h e polymer. The s u g g e s t e d a p p l i c a t i o n is i n separating water and chlorinated hydrocarbons.
P a t e n t number: J P 4 2 9 0 5 3 0 Date: 15 O c t o b e r 1992 Inventor: S. A s a k u m a Applicant: S u m i t o m o Bakelite Co Ltd
Antioxidant for cooking oils C o o k i n g oils h a v e a relatively s h o r t s h e l f life, c o n s i d e r i n g t h a t t h e y c o n t a i n s n e x t to n o w a t e r or
Gel-filled membrane pores Liquid c h r o m a t o g r a p h y e m p l o y s t u b e s or b e d s p a c k e d w i t h fine p a r t i c l e s to c a r r y o u t differential s e p a r a t i o n s of c o m p o u n d s : m o r e recently, hollow fibre m e m b r a n e s h a v e b e e n p r o p o s e d for the s a m e application. Materials suitable by their p h y s i c a l qualities, s u c h a s f l u o r i n a t e d polyolefins are h y d r o p h o b i c : filling the p o r e s with a h y d r o p h f l i c m a t e r i a l will e n h a n c e its p e r f o r m a n c e . H o e c h s t modifies the b a s i c m a t e r i a l by: w e t t i n g w i t h a s u r f a c t a n t , filling t h e fibres with a s o l u t i o n of polyvinyl alcohol a n d divinyl s u l p h o n e , w a t e r w a s h i n g the fibres to c l e a n t h e s u r f a c e s b u t r e t a i n t h e PVA/DVS s o l u t i o n i n the pores, filing t h e fibres with a s o l u t i o n of a b a s e to c r o s s l i n k the PVA/DVS as a n a q u e o u s gel, t h e n finally w a s h i n g o u t the b a s e to leave gel-filled pores.
P a t e n t number: US 5 1 6 0 6 2 7 Date: 3 N o v e m b e r 1992 Inventors: E.L. Cussler, G.E. Gillberg-LaForce, M.J. S a n s o m e , D.K. S c h i s l a Applicant: H o e c h s t C e l a n e s e Corp
Membrane
T e c h n o l o q t l No. 4 0
Patents This is a list of r e c e n t l y p u b l i s h e d patents covering designs a n d i n v e n t i o n s of r e l e v a n c e to s y n t h e t i c m e m b r a n e technology. W h e r e t h e s a m e device h a s b e e n p a t e n t e d i n s e v e r a l c o u n t r i e s , we n o r m a l l y give t h e B r i t i s h p a t e n t n u m b e r . If t h e r e is n o UK p a t e n t , we give t h e n u m b e r of a n E n g l i s h - l a n g u a g e p a t e n t , if o n e exists. The p a t e n t s list is c o m p i l e d from i n t e r n a t i o n a l s o u r c e s b y BHR G r o u p ' s i n f o r m a t i o n service. The facility c a n also b e u s e d to carry out retrospective patent s e a r c h e s - - to test t h e validity, n o v e l t y or i n f r i n g e m e n t of e x i s t i n g p a t e n t s or n e w ideas. BHR G r o u p , Cranfield, Bedford MK43 0AJ, UK, will p r o v i d e free estimates on request. C o u n t r i e s c a n b e identified b y the code in f r o n t of t h e n u m b e r a s follows: AT A u s t r i a AU A u s t r a l i a BE B e l g i u m BR Brazil CH S w i t z e r l a n d DD E a s t G e r m a n y DE West G e r m a n y DK D e n m a r k EP E u r o p e a n P a t e n t E S S p a i n FI F i n l a n d FR F r a n c e GB B r i t a i n HU H u n g a r y IL Israel IR Eire IT Italy JP Japan KP North Korea LI L i e c h t e n s t e i n LU L u x e m b o u r g NL N e t h e r l a n d s NO Norway RO R o m a n i a SE S w e d e n US U n i t e d S t a t e s SU Soviet U n i o n WO World P a t e n t (Patent Treaty Cooperation publication) BHR G r o u p does n o t o p e r a t e a d o c u m e n t delivery service for p a t e n t s , b u t full copies of t h e o r i g i n a l p a t e n t d o c u m e n t s c a n be o b t a i n e d from t h e following addresses: The B r i t i s h L i b r a r y P a t e n t E x p r e s s 25 S o u t h a m p t o n B u i l d i n g s L o n d o n WC2A lAW, UK Fax: 071 3 2 3 7 2 3 0 (The B r i t i s h L i b r a r y will also s u p p l y a list of UK l i b r a r i e s included in the Patent I n f o r m a t i o n Network.) US P a t e n t Office
M e m b r a n e T e c h n o l o g y No. 4 0
Scientific L i b r a r y 15th a n d E a s t Streets, NW W a s h i n g t o n , DC 2 0 2 3 l, USA The J a p a n e s e P a t e n t Office 4-3 Kaksumigaseki 3-chome C h i y o d a - k u , Tokyo 100, J a p a n
Fluorine t r e a t m e n t for membrane A p a t e n t i n t h e l a s t i s s u e referred to c h l o r i n e t o l e r a n c e i n m e m b r a n e s , a n d to relatively low c o n c e n t r a t i o n s at that. This p a t e n t d e s c r i b e s the u s e of a 0.025-2% fluorine-in-helium m i x t u r e , followed b y air oxidation, to i m p r o v e the p r o p e r t i e s of a polysulphone membrane.The a p p l i c a t i o n of t h e t r e a t e d m e m b r a n e is i n p r o t e i n r e m o v a l from a q u e o u s s o l u t i o n s , a t a s k r e q u i r i n g r e s i s t a n c e to fouling. The initial m a t e r i a l h a s a pore size of 0 . 0 0 1 - 1 0 m i c r o n , i.e. it c a n b e s u i t a b l e for microffltration, u l t r a f i l t r a t i o n or r e v e r s e o s m o s i s . T h e pore size is not substantially altered by the t r e a t m e n t . The m e c h a n i s m at t h e m o l e c u l a r scale a p p e a r s to be t h e f o r m a t i o n of -CHF- g r o u p s a t the s u r f a c e of the m e m b r a n e . T h e s e m o d i f y the h y d r o p h i l i c t y of the m e m b r a n e surface without affecting the pores.
Patent number: US 5 1 5 1 1 8 3 Date: 29 S e p t e m b e r 1992 Inventors: R.H. S e d a t h , D.R. Taylor, L.S. White Applicant: Allied-Signal Inc.
Hollow-fibre polyvinylpyrrolidone u s e This E u r o p e a n P a t e n t from a J a p a n e s e c o m p m l y offers a n e w m o d i f i c a t i o n of the h y d r o p h o b l c n a t u r e of p o l y s u l p h o n e r e s i n s . V a r i o u s h y d r o p h i l i c m a t e r i a l s are incorporated in these p o l y s u l p h o n e s , often to allow w e t t i n g of the s u r f a c e to t a k e
place, s o m e t i m e s b e i n g lost from t h e m e m b r a n e via leaching. This p r o c e s s fixes a hydrophilic material in the polymer matrix by cross-llnking so t h a t it c a n n o t l e a c h out. The c h o s e n c o m p o u n d is polyvinylpyrrolidone: the chosen m e t h o d is to s p i n a hollow fibre from a s o l u t i o n c o n t a i n i n g t h e polysulphone a n d the p o l y v i n y l p y r r o l i d o n e , k e e p it w e t t e d a s a hydrogel, a n d c r o s s l i n k it u s i n g g a m m a radiation.
Patent number: EP 5 0 9 6 6 3 Date: 21 O c t o b e r 1992 Inventors: T. K o b a y a s h i , K. Tanaka Applicant: T o r a y I n d u s t r i e s Inc.
Gas c l e a n i n g system H y d r o g e n s u l p h i d e is a c o m m o n c o n s t i t u e n t of n a t u r a l g a s a n d of g e o t h e r m a l s t e a m . It is n o t d e s i r a b l e for t h e H2S to r e m a i n i n t h e n a t u r a l gas, n o r c a n it b e v e n t e d from g e o t h e r m a l e n e r g y plants. There are several w e l l - e s t a b l i s h e d m e t h o d s for r e m o v i n g t h e H2S; m o s t involve d i s s o l v i n g t h e acidic c o m p o n e n t s of t h e n a t u r a l gas i n a s o l v e n t containing a base such as p o t a s s i u m c a r b o n a t e or a n e t h a n o l a m i n e . The s o l v e n t is h e a t e d to r e l e a s e t h e H2S, w h i c h is t h e n u s u a l l y c o n v e r t e d to elemental s u l p h u r in a controlled-oxidation gas-phase process. T h a t s e q u e n c e of e v e n t s is m o s t effective w h e n H2S c o n c e n t r a t i o n s a r e h i g h or a large v o l u m e of gas is c l e a n e d . W h e n the r e v e r s e is t r u e , it is c h e a p e r a n d / or m o r e c o n v e n i e n t to operate a process which captures a n d oxidizes t h e H2S i n a single step. Such processes have been a v a i l a b l e for t h r e e d e c a d e s , m o s t l y u s i n g c h e l a t e d i r o n or v a n a d i u m c o m p o u n d s which are e a s i l y r e d u c e d from ferric to f e r r o u s or from V[V] to V[III] b y t h e H2S (which is oxidized to produce sulphur), and then can
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Patents b e reoxidized i n air. The c h e l a t i n g a g e n t is n i t r i l o t r i a c e t i c acid or EDTA. The s o l u t i o n c a n t h e n b e recycled to the g a s c l e a n i n g u n i t . The s u l p h u r is filtered from t h e s o l u t i o n a n d is of c o m m e r c i a l quality. As w i t h m a n y g a s c l e a n i n g processes involving scrubbing solutions, the f u n d a m e n t a l r e a c t i o n is n o t t h e o n l y o n e to t a k e place, a n d it is n e c e s s a r y to eliminate byproducts a n d chelate d e g r a d a t i o n c o m p o u n d s so t h a t t h e gas c l e a n i n g p r o c e s s r e m a i n s effective. T h i s is m o s t easily achieved by bleeding the system a n d r e p l e n i s h i n g w i t h f r e s h active agent. The p a t e n t r e d u c e s l o s s e s of the iron/chelate c o m p o u n d by adding a n extra nanofiltration s t e p after t h e s u l p h u r is r e m o v e d . The m e m b r a n e allows w a t e r a n d s o l u t e s w i t h a m o l e c u l a r weight below a b o u t 225 to p a s s t h r o u g h , b u t r e t a i n s t h e chelate. I n t h i s way impurities and degradation p r o d u c t s are r e m o v e d w i t h o u t loss of t h e active i n g r e d i e n t .
P a t e n t n u m b e r : WO 9 2 1 7 4 0 1 Date: 15 O c t o b e r 1992 Inventors: J.G. G r i e r s o n , M.C. Alien Applicant: Dow C h e m i c a l Co
Soya milk preparation Tofu, or s o y a b e a n c u r d , is m a d e b y h e a t i n g t h e l i q u i d from s t e e p i n g g r o u n d soya b e a n s i n water. T h i s 'soya m i l k ' is traditionally made by grinding a n d steeping the soya beans, t h e n filtering t h e m i x t u r e after the b e a n s h a v e first b e e n s o a k e d i n a c h a n g e of w a t e r for s o m e time. If t h e s o a k i n g s t e p is o m i t t e d t h e n the m i l k a n d c u r d h a v e a h a r s h t a s t e a n d smell; t h i s is c a u s e d b y the a c t i o n of a s o l u b l e e n z y m e which the soaking step leaches o u t of t h e b e a n s . The p a t e n t from K i k k o m a n ( p r o b a b l y k n o w n i n t h e West a s a soy s a u c e m a n u f a c t u r e r ) s h o r t e n s the p r o c e s s i n g t i m e b y o m i t t i n g the s o a k i n g s t e p a n d b y u s i n g a n ultraffltration m e m b r a n e between
10
the s t e e p i n g a n d c o a r s e f i l t r a t i o n steps. The m e m b r a n e r e t a i n s high-molecnlar-weight c o m p o u n d s from the b e a n milk, s u c h a s p r o t e i n s , while allowing carbohydrates s u c h as o l i g o s a c c h a r i d e s to p a s s t h r o u g h . R e m o v i n g o l i g o s a c c h a r i d e s from p u l s e s or t h e i r p r o c e s s e d products has an incidental d o u b l e olfactory benefit: t h e b e a n c u r d fiavour is i m p r o v e d a s m e n t i o n e d earlier, a n d the i n c i d e n c e of digestive t r a c t f l a t u s ( c a u s e d w h e n g u t b a c t e r i a digest oligosaccharides and produce m e t h a n e ) is d i m i n i s h e d .
n u t r i e n t s w h i c h w o u l d allow b a c t e r i a or m o u l d s to prosper. The d o u b l e b o n d s p r e s e n t i n a l m o s t all vegetable otis are oxidized w h e n i n c o n t a c t with the air or dissolved oxygen, f o r m i n g l o n g - c h a i n fatty a c i d s w h i c h give the c h a r a c t e r i s t i c r a n c i d smell. D a i n i p p o n c l a i m t h e u s e of a deoxygenating membrane -poly-4-methylpent-l-ene -- which is p e r m e a b l e to oxygen dissolved i n t h e oil. If t h e oxygen c o n t e n t is lowered to 0 . 5 - 2 . 0 p p m t h e n the k e e p i n g q u a l i t i e s of the oil will be improved.
P a t e n t number: J P 4 2 9 9 9 5 2 Date: 23 October 1992 Inventor: N. Horie Applicant: K i k k o m a n Corp
P a t e n t number: J P 4 2 9 0 5 0 2 Date: 15 O c t o b e r 1992 Inventor: K. K u r i y a m a Applicant: D a i n i p p o n I n k & C h e m i c a l Inc
Solvent resistant membrane The s o l v e n t s to be r e s i s t e d are halogen-substituted hydrocarbons; the m e m b r a n e m a t e r i a l is a polyimide; the m e a n s of i n t r o d u c i n g r e s i s t a n c e is to r e a c t o x y p h t h a l i c acid a n h y d r i d e or a derivative with a diamine which contains a p r o p o r t i o n of a d i a m i n o s f l o x a n e . I n the m e m b r a n e the s i l i c o n / c a r b o n ratio at the s u r f a c e is greater t h a n the t h e o r e t i c a l o n e c a l c u l a t e d from the m o l e c u l a r s t r u c t u r e of the polymer, while c o n f o r m i n g to t h e o r y i n the b o d y of t h e polymer. The s u g g e s t e d a p p l i c a t i o n is i n separating water and chlorinated hydrocarbons.
P a t e n t number: J P 4 2 9 0 5 3 0 Date: 15 O c t o b e r 1992 Inventor: S. A s a k u m a Applicant: S u m i t o m o Bakelite Co Ltd
Antioxidant for cooking oils C o o k i n g oils h a v e a relatively s h o r t s h e l f life, c o n s i d e r i n g t h a t t h e y c o n t a i n s n e x t to n o w a t e r or
Gel-filled membrane pores Liquid c h r o m a t o g r a p h y e m p l o y s t u b e s or b e d s p a c k e d w i t h fine p a r t i c l e s to c a r r y o u t differential s e p a r a t i o n s of c o m p o u n d s : m o r e recently, hollow fibre m e m b r a n e s h a v e b e e n p r o p o s e d for the s a m e application. Materials suitable by their p h y s i c a l qualities, s u c h a s f l u o r i n a t e d polyolefins are h y d r o p h o b i c : filling the p o r e s with a h y d r o p h f l i c m a t e r i a l will e n h a n c e its p e r f o r m a n c e . H o e c h s t modifies the b a s i c m a t e r i a l by: w e t t i n g w i t h a s u r f a c t a n t , filling t h e fibres with a s o l u t i o n of polyvinyl alcohol a n d divinyl s u l p h o n e , w a t e r w a s h i n g the fibres to c l e a n t h e s u r f a c e s b u t r e t a i n t h e PVA/DVS s o l u t i o n i n the pores, filing t h e fibres with a s o l u t i o n of a b a s e to c r o s s l i n k the PVA/DVS as a n a q u e o u s gel, t h e n finally w a s h i n g o u t the b a s e to leave gel-filled pores.
P a t e n t number: US 5 1 6 0 6 2 7 Date: 3 N o v e m b e r 1992 Inventors: E.L. Cussler, G.E. Gillberg-LaForce, M.J. S a n s o m e , D.K. S c h i s l a Applicant: H o e c h s t C e l a n e s e Corp
Membrane
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