Recent Technical Developments in the Finnish Pulp and Paper Industry

about 20 years to discover that over 70 % of exports consisted of wood products. ... ably higher yield of tall oil, or about 200 kg/ton of pulp. Whole...
1 downloads 0 Views 914KB Size
Download PDF
7 Recent Technical Developments in the Finnish Pulp and Paper Industry LARS N O R D M A N The Finnish Pulp and Paper Research Institute, P.O. Box 136, 00101 Helsinki 10, Finland

T h e t u r n i n g - p o i n t i n the d e v e l o p m e n t w h i c h brought about a change i n F i n l a n d ' s e c o n o m y f r o m one b a s e d upon a g r i c u l t u r e to one b a s e d upon i n d u s t r i a l p r o d u c t i o n c a m e about one h u n d r e d y e a r s ago. One of the r e a s o n s f o r this was the d i s c o v e r y at that t i m e that the t r a d i t i o n a l raw m a t e r i a l s f o r p a p e r m a k i n g , l i n e n and r a g s , c o u l d be r e p l a c e d by wood f i b r e s . T h e e x p l o i t a t i o n of this new s o u r c e of raw m a t e r i a l opened up new o p p o r t u n i t i e s f o r u t i l i s a t i o n of the e x t e n s i v e f o r e s t r e s o u r c e s of F i n l a n d , not j u s t f o r the t r a d i t i o n a l e x p o r t of t i m b e r , but a l s o f o r the p r o d u c t i o n of m o r e h i g h l y p r i c e d f i b r e p r o d u c t s . T h e e v o l u t i o n w h i c h s t a r t e d a c e n t u r y ago has m a d e F i n l a n d one of the l e a d i n g n a tions i n the f i e l d of pulp and p a p e r . Of c o u r s e , the g r o w t h of this i n d u s t r y has not been steady and smooth, but has been i n f l u e n c e d by the d r a m a t i c h i s t o r i c a l and e c o n o m i c events of the p a s t h u n d r e d y e a r s . S p e c t a c u l a r g r o w t h has been e x p e r i e n c e d d u r i n g the y e a r s f o l l o w i n g the l a s t war, a p e r i o d m a r k e d by a doubling, on the a v e r a g e of the p r o d u c t i o n of pulp, p a p e r and b o a r d e v e r y ten y e a r s . C u r r e n t l y , the p r o d u c t i o n of c h e m i c a l pulp a m o u n t s to 4.5 m i l l i o n tons. T h e c o r r e s p o n d i n g f i g u r e s f o r p a p e r and p a p e r b o a r d a r e n e a r l y 5.5 m i l l i o n tons. In r e s p e c t to p a p e r b o a r d , g r o w t h has been e v e n f a s t e r than the a v e r a g e f o r the e n t i r e i n d u s t r y ; i t i s now o v e r 10 t i m e s as g r e a t as that i n 1950. A g l a n c e at the s t a t i s t i c s m a k e s i t a p p a r e n t that the e x p o r t v a l u e of a l l f o r e s t p r o d u c t s , i n c l u d i n g t i m b e r and other p r o d u c t s f r o m the m e c h a n i c a l w o o d w o r k i n g i n d u s t r i e s , a m o u n t s to about 50 p e r cent of o u r total f o r e i g n t r a d e . T h i s m a k e s i t c l e a r l y evident how g r e a t l y F i n l a n d depends upon u t i l i s a t i o n of the f o r e s t s . In the past, this f i g u r e was e v e n h i g h e r , and we n e e d not look b a c k m o r e than about 20 y e a r s to d i s c o v e r that o v e r 70 % of e x p o r t s c o n s i s t e d of wood p r o d u c t s . A t the s a m e t i m e as the r e l a t i v e s h a r e of wood b a s e d e x p o r t s i n the f o r e i g n t r a d e has d i m i n i s h e d by r e a s o n

162

7.

NORDMAN

Finnish Pulp and Paper Industry

163

of a c o r r e s p o n d i n g l y v i g o r o u s g r o w t h i n the e x p o r t s of the m e t a l i n d u s t r y , i m p o r t a n t changes have a l s o o c c u r r e d w i t h i n the w o o d w o r k i n g i n d u s t r y as c o n c e r n the v o l u m e and value of e x p o r t s f r o m the d i f f e r e n t s e c t o r s of the i n d u s t r y . T h e e x p o r t of p u l p wood has to a g r e a t extent c e a s e d , to be r e p l a c e d by i m p o r t , w h i c h has d u r i n g s o m e y e a r s a m o u n t e d to as m u c h as 10 p e r cent of the raw m a t e r i a l u t i l i s e d by o u r i n d u s t r y . A r e c e n t t r e n d i n the e x p o r t f i g u r e s i n d i c a t e s that the s t e a d i l y g r o w i n g p a p e r i n d u s t r y n e e d s an i n c r e a s i n g a m o u n t of the pulp p r o d u c e d i n F i n l a n d ; as a c o n s e q u e n c e s the peak i n pulp e x p o r t s was attained i n 1970. In r e g a r d to the e x p o r t of m e c h a n i c a l pulp, the t u r n i n g point was r e a c h e d m u c h e a r l i e r ; today, the e x p o r t of g r o u n d w o o d pulp, i s e x t r e m e l y s m a l l , notwithstanding the a n n u a l p r o d u c t i o n of m o r e than 2 m i l l i o n tons. H o w e v e r this does not i m p l y a future r e d u c t i o n i n the m a n u f a c t u r e of c h e m i c a l m a r k e t pulp. C o n s t r u c t i o n w o r k c u r r e n t l y i n p r o g r e s s w i l l by the end of this y e a r add s o m e 100 000 tons of b l e a c h e d s u l phate pulp, and i n 1977 a f u r t h e r amount of 250 000 tons to the capacity. D e s p i t e an e x t e n s i v e r e f o r e s t a t i o n p r o g r a m m e , s h o r t a g e of raw m a t e r i a l w i l l c o n s t i t u t e a l i m i t i n g f a c t o r to the g r o w t h of the f i b r e - p r o d u c i n g i n d u s t r y . Of c o u r s e , this s i t u a t i o n i s not unique to F i n l a n d , and the s o l u t i o n s to the p r o b l e m s w h i c h p r e s e n t t h e m s e l v e s by r e a s o n of the raw m a t e r i a l shortage a r e f a m i l i a r to m o s t c o u n t r i e s that p r o d u c e pulp, p a p e r and b o a r d . F o r e x t e n s i o n of the a v a i l a b l e r e s o u r c e s , three w a y s s e e m open: -

m o r e e x t e n s i v e u t i l i s a t i o n of the f o r e s t s p u l p i n g to a h i g h e r y i e l d , and t e c h n i c a l u t i l i s a t i o n of the n o n f i b r o u s c o m p o n e n t s of the wood. M o r e e x t e n s i v e u t i l i s a t i o n of wood raw m a t e r i a l f r o m the f o r e s t s i s a c h i e v a b l e i n a n u m b e r of d i f f e r e n t w a y s . Studies c a r r i e d out i n F i n l a n d have been f o c u s e d upon w h o l e - t r e e u t i l i z ation, the use of stumps f r o m both m i n e r a l s o i l and swamps, and the p u l p i n g of f a s t g r o w i n g h a r d w o o d s p r o d u c e d by m e a n s of s h o r t - r o t a t i o n c y c l e c u l t i v a t i o n . D e v e l o p m e n t w o r k i n r e l a tion to h a r v e s t i n g m a c h i n e r y i s w e l l u n d e r way, and stump h a r v e s t e r s and w h o l e - t r e e h a r v e s t e r s a r e now p r o d u c i n g c h i p s on a c o m m e r c i a l s c a l e . In p a r a l l e l with s u r v e y s of the a v a i l a b i l i t y of r e s i d u a l wood r e s o u r c e s , and the d e v e l o p m e n t of h a r v e s t i n g equipment, p u l p i n g i n v e s t i g a t i o n s have been c a r r i e d out f o r c h a r a c t e r i s a t i o n of the r a w m a t e r i a l d e r i v e d f r o m the v a r i o u s s o u r c e s . In g e n e r a l , e x p e r i e n c e points to sulphate

164

CELLULOSE AND FIBER SCIENCE

p u l p i n g being the only p u l p i n g p r o c e s s that i s a p p l i c a b l e i n p r a c t i c e . T h e pulps p r o d u c e d a r e of s l i g h t l y l o w e r y i e l d and have s l i g h t l y i n f e r i o u r s t r e n g t h p r o p e r t i e s than those obtained f r o m the t r e e trunk. A n i n t e r e s t i n g d e v e l o p m e n t f o r F i n l a n d , with i t s l a r g e a r e a s of swamp, i s that the s w a m p s i n a d d i t i o n to f u e l peat y i e l d raw m a t e r i a l f o r the pulp i n d u s t r y . Stumps and f a l l e n t r e e t r u n k s b u r i e d i n the s w a m p s f o r up to 3000 y e a r s c a n be s e p a r a t e d and c o l l e c t e d to an a m o u n t of r o u g h l y 3 kg p e r c u b i c m e t r e of peat. W i t h the i n c r e a s e d use of peat f o r f u e l , i t has been c a l c u l a t e d that by 1980 about 200 000 m s o l i d m e a s u r e of s t u m p s w i l l be a v a i l a b l e . In c o n t r a s t to stumps obtained f r o m m i n e r a l s o i l , bog s t u m p s a r e f r e e f r o m bark, sand and stones. One i n t e r e s t i n g f e a t u r e of the s u l p h a t e - p u l p i n g of stumps i s that the l o w e r y i e l d i s c o m p e n s a t e d by a c o n s i d e r a b l y h i g h e r y i e l d of t a l l o i l , o r about 200 kg/ton of pulp. 3

W h o l e - t r e e c h i p s f r o m thinnings have been s u c c e s s f u l l y p u l p e d by a p p l i c a t i o n of the sulphate p r o c e s s . T h e pulp can be added, even to s u c h a d e m a n d i n g p a p e r q u a l i t y as s a c k paper, without e x e r c i s i n g any i n f l u e n c e upon the p h y s i c a l p r o p e r t i e s of the sheet. S h o r t r o t a t i o n h a r d w o o d s y i e l d the l o w e s t s t r e n g t h pulp, w h i c h i s to be e x p e c t e d with a v i e w to the s h o r t f i b r e length of young h a r d w o o d t r e e s . T h e s e c o n d way w h i c h e n a b l e s e x t e n s i o n of the a v a i l a b l e r e s o u r c e s of raw m a t e r i a l i s c o n n e c t e d with the p r o d u c t i o n of pulp at a h i g h e r y i e l d . In F i n l a n d today, the d o m i n a t i n g i n t e r e s t i s c e n t e r e d upon the p r o d u c t i o n of m e c h a n i c a l pulp. T h i s q u e s t i o n i s i n s e p a r a b l e f r o m the q u e s t i o n of o p t i m i s a t i o n of the use of the wood r a w - m a t e r i a l f o r d i f f e r e n t p a p e r and b o a r d q u a l i t i e s , to w h i c h can be added the a s p e c t s i n t r o d u c e d by the p r e sent t r e n d t o w a r d s r e d u c e d g r a m m a g e . The m a i n f o c u s i s on t h e r m o m e c h a n i c a l pulp, an i n t e r e s t e v i d e n c e d both by c o n s i d e r able i n v e s t m e n t s i n r e s e a r c h into this pulp q u a l i t y and i t s m a n u f a c t u r i n g p r o c e s s , and by the new i n s t a l l a t i o n s announced, w h i c h w i l l by the end of 1977 supply m o r e than 300 000 tons of t h e r m o m e c h a n i c a l pulp f o r p r i n t i n g g r a d e s . A t p r e s e n t two t h e r m o m e c h a n i c a l pulping lines are i n operation i n F i n l a n d , e a c h of t h e m w i t h a c a p a c i t y of about 50-70 tons/day. One i n s t a l l a t i o n i n K y r o i s b a s e d upon the D e f i b r a t o r p r o c e s s ; the p r o d u c t i s u s e d as p a r t of the f u r n i s h f o r w a l l p a p e r b a s e . T h e o t h e r line i n o p e r a t i o n , i s f r o m m a n y standpoints the m o s t i n t e r e s t i n g i n s t a l l a t i o n i n the a r e a of m e c h a n i c a l p u l p i n g i n F i n l a n d today. T h e r e f i n e r , a Jylhà-finer, has been d e v e l o p e d by the Jylhàvaara w o r k s of the U n i t e d P a p e r M i l l s , and i s i n s t a l l e d i n this company's K a i p o l a M i l l . T h i s e q u i p m e n t has been subj e c t e d to e x t e n s i v e t r i a l r u n s , of w h i c h the a i m has been a

7.

NORDMAN

Finnish Pulp and Paper Industry

165

s i n g l e - f u r n i s h n e w s p r i n t sheet. T h i s was found p o s s i b l e not only f o r a s t a n d a r d g r a m m a g e , but a l s o f o r light weight p a p e r s of 45, and even 40 g/m^. T h e c o m b i n e d effect of the o m i s s i o n of c h e m i c a l pulp and the r e d u c e d g r a m m a g e i s a d i m i n u t i o n i n the wood c o n s u m p t i o n a m o u n t i n g to about 40 p e r cent b a s e d upon p r i n t i n g a r e a . E v e n i f c o m m e r c i a l i n s t a l l a t i o n s of r e f i n e r s f o r t h e r m o m e c h a n i c a l p u l p i n g a r e i n continuous p r o d u c t i o n , and new i n s t a l l a t i o n s a r e being m a d e not only i n F i n l a n d but a l l o v e r the w o r l d , the p r o c e s s i s s t i l l r e g a r d e d as b e i n g u n d e r d e v e l o p ment; i t i s hoped that c o n t i n u e d r e s e a r c h , both into the fundam e n t a l s of f i b r e s e p a r a t i o n and into p u r e l y p r a c t i c a l s t u d i e s of the p r o c e s s v a r i a b l e s , w i l l be of b e n e f i t both i n i m p r o v e d e c o n o m y , a n d i n the v e r s a t i l i t y of the f i b r e r a w m a t e r i a l obt a i n e d . It i s hoped that this w i l l e v e n t u a l l y f a c i l i t a t e the u s e of m e c h a n i c a l pulp, even f o r q u a l i t i e s of p a p e r w h i c h have so f a r been p r o d u c e d only f r o m l o w e r - y i e l d p u l p s . In Sweden, a r e s e a r c h p r o j e c t c o n c e r n e d with t h e r m o m e c h a n i c a l p u l p i n g i s long advanced, and i n F i n l a n d a p r o j e c t was s t a r t e d i n o u r Institute this y e a r . F o r this p u r p o s e , t h e r e i s a v a i l a b l e a p i l o t - p l a n t i n s t a l l a t i o n , b a s e d upon a 1000 kW double d i s c r e f i n e r , w h i c h can be o p e r a t e d both u n d e r a t m o s p h e r i c and e l e v a t e d p r e s s u r e . T h e c h i p - f e e d i n g s y s t e m , d e v e l o p e d a n d patented by the I n s t i tute, h a s been d e s i g n e d i n p a r t i c u l a r to a v o i d b l o w - b a c k phen o m e n a . A not i n s i g n i f i c a n t p a r t of the w o r k i s b e i n g d i r e c t e d t o w a r d s q u a n t i f i c a t i o n of the l o a d i m p o s e d upon the e n v i r o n m e n t by the p r o c e s s . It m i g h t s e e m f r o m what h a s been s a i d that r e f i n e r m e c h a n i c a l pulp, and t h e r m o m e c h a n i c a l pulp i n p a r t i c u l a r c o m p l e t e l y d o m i n a t e the thinking i n F i n l a n d . It i s t h e r e f o r e i m p o r t a n t to point out that d u r i n g 1975 the l a r g e s t p a p e r m a c h i n e f o r L W C b a s e p a p e r i n the w o r l d was s t a r t e d up at K a u k a s b a s e d e n t i r e l y upon stone g r o u n d w o o d obtained f r o m a b r a n d new, c o n v e n t i o n a l g r o u n d w o o d m i l l , with f o u r T a m p e l l a g r i n d e r s . A s u r v e y of d e v e l o p m e n t w i t h i n the p u l p i n g s e c t o r w o u l d be i n c o m p l e t e i f no m e n t i o n was m a d e of two p r o j e c t s f o r the c h a n g e o v e r f r o m s u l p h i t e - to s u l p h a t e - p u l p i n g . T h e K y m i C o m pany, at i t s K u u s a n k o s k i m i l l , w i l l d i s c o n t i n u e the p r o d u c t i o n of b l e a c h e d sulphite pulp i n 1977 when a new continuous sulphate l i n e , with a c a p a c i t y of 160 000 tons a y e a r , w i l l s t a r t p r o d u c t i o n . In this m i l l , the f i r s t K a m y r d i s p l a c e m e n t b l e a c h i n g p l a n t w i l l be i n s t a l l e d , f o l l o w i n g s e v e r a l y e a r s of s u c c e s s f u l p i l o t plant t r i a l s . A s i m i l a r c h a n g e o v e r f r o m sulphite to sulphate p u l p p r o d u c t i o n i s i n p r o g r e s s at V e i t s i l u o t o . T o w a r d s the end of 1977, the o l d sulphite m i l l w i l l be r e p l a c e d by a sulphate

166

CELLULOSE AND FIBER SCIENCE

m i l l ; the K a m y r d i g e s t e r w i l l have a c a p a c i t y of f r o m 250 000 to 300 000 tons p e r annum, dependent upon w h e t h e r softwood or h a r d w o o d pulp i s being p r o d u c e d . When a c c o u n t i s taken of these two changes f r o m sulphite to sulphate pulp p r o d u c t i o n , a l o n g with the p r e v i o u s l y noted a d d i t i o n to m a r k e t pulp c a p a c i t y , e n t i r e l y c o n c e r n e d with sulphate pulp, and with the c l o s i n g of two s m a l l sulphite m i l l s i n c l u d e d i n the c a l c u l a t i o n s ; a v e r y m a r k e d shift i s o b s e r v a b l e i n the r a t i o between s u l p h a t e - and s u l p h i t e - p u l p p r o d u c t i o n i n F i n l a n d . A f t e r two y e a r s , sulphite pulp w i l l amount to l e s s than 25 % of the total c h e m i c a l pulp p r o d u c e d . T h e F i n n i s h P a p e r I n d u s t r y has c o n c e n t r a t e d upon the p r o d u c t i o n of b u l k q u a l i t i e s , m a i n l y i n the p r i n t i n g and p a c k a g i n g l i n e s . G r o w t h i n the i n d u s t r y has a l s o o c c u r r e d w i t h i n these s e c t o r s , as i s o b s e r v a b l e f r o m the s i z e d i s t r i b u t i o n of the p a p e r m a c h i n e s , with m o s t of the new i n s t a l l a t i o n s f a l l i n g w i t h i n the u p p e r w i r e width r a n g e . M o s t of the m a c h i n e s i n s t a l l e d have been b u i l t i n F i n l a n d . A t y p i c a l e x a m p l e i s p r o v i d e d by the new m a c h i n e at K a u k a s ; i t has a w i r e width of 8100 mm, and a m a x i m u m speed of 1100 m / m i n , i t was b u i l t by V a l m e t Oy, and i t p r o d u c e s base paper f o r L W C c o a t i n g g r a d e s . T h e c o a t i n g i s e f f e c t e d on a Wàrtsilâ o f f - m a c h i n e blade c o a t e r . W i t h this c a p a c i t y of 130 000 tons of c o a t e d w o o d - c o n t a i n i n g L W C - g r a d e s , i t i s c l a i m e d that the K a u k a s i n s t a l l a t i o n i s the l a r g e s t of its k i n d i n the w o r l d . A n o t h e r w o r l d r e c o r d - h o l d e r i s the c o n d e n s e r t i s s u e - m a c h i n e of T e r v a k o s k i , c o n s t r u c t e d by A. A h l s t r ô m C o m pany's K a r h u l a w o r k s , and w h i c h was s t a r t e d up l a s t y e a r . T h e w i r e width i s 5000 mm, and the m a x i m u m s p e e d 400 m / m i n , with a g r a m m a g e range of 10-30 g/m^. T h e f a m i l y of t w i n - w i r e m a c h i n e s a l s o i n c l u d e s a F i n n i s h d e v e l o p m e n t , the S y m - F o r m e r by V a l m e t . T h e n a m e "SymF o r m e r " i s d e r i v e d f r o m the w o r d " s y m m e t r i c a l " , and i n d i cates that d r a i n a g e o c c u r s s y m m e t r i c a l l y t o w a r d both s i d e s of the sheet. H o w e v e r , with a v i e w to s a f e g u a r d i n g good r e t e n t i o n , the i n i t i a l p a r t of the d r a i n a g e takes p l a c e on a F o u r d r i n i e r type w i r e ; only a f t e r a c e r t a i n t i m e i s the d i r e c t i o n of d r a i n a g e r e v e r t e d by the a c t i o n of the double w i r e and i t s d r a i n a g e e l e m e n t s . The s y m m e t r i c a l d r a i n a g e concept has a l s o been f o l l o w e d up by V a l m e t , i n the f o r m of a S y m - p r e s s , of w h i c h the s e c o n d v e r s i o n has been i n s t a l l e d on the K a u k a s m a c h i n e . One other new d e v e l o p m e n t i s the h i g h c o n s i s t e n c y h e a d box, o r i g i n a l l y i n v e n t e d i n Sweden at the S w e d i s h W o o d R e s e a r c h Institute, but now f u r t h e r d e v e l o p e d by the A . A h l s t r ô m

7.

NORDMAN

Finnish Pulp and Paper Industry

167

C o m p a n y . T h i s headbox, d e v e l o p e d u n d e r the n a m e of F o r m F l o w , has been t r i e d at the company's K a u t t u a p a p e r m i l l on a m a c h i n e , with a g r a m m a g e range f r o m 65 to 250 g/m^, and a s p e e d of 200 m / m i n . T h e p r i n c i p l e of the F o r m F l o w headbox i s the a c h i e v e m e n t of v i g o r o u s m i c r o t u r b u l e n c e i n the pulp s u s ­ p e n s i o n , w h i c h i s p u m p e d to the headbox. S i n c e the c o n s i s t e n c y i s as high as 2 to 4 % i t f o l l o w s , that the v o l u m e of b a c k w a t e r a m o u n t s to no m o r e than 10 to 20 % of that of a n o r m a l p a p e r m a c h i n e . T h i s a l s o l e a d s to s a v i n g s i n c h e s t s , pumps, and w i r e length. E x p e r i e n c e g a i n e d with the K a u t t u a m a c h i n e has b e e n v e r y p r o m i s i n g ; the p a p e r has a good f o r m a t i o n , and a h i g h Ζ-direction s t r e n g t h . A s was stated at the beginning, three w a y s a r e open f o r the e x t e n s i o n of a v a i l a b l e wood r e s o u r c e s ; two of t h e m p r o v i d e o p p o r t u n i t i e s f o r the augmentation of pulp and p a p e r p r o d u c t i o n . T h e t h i r d way i s a i m e d at u t i l i s a t i o n of the n o n f i b r o u s c o m p o ­ nents of the wood, and i s a c c o r d i n g l y m o r e c o n c e r n e d with the e c o n o m i c s of the i n t e g r a t e d p r o c e s s , and with e n v i r o n m e n t a l q u e s t i o n s . T h i s a r e a c o n t a i n s a n u m b e r of d e v e l o p m e n t s w o r t h r e p o r t i n g . In u t i l i s a t i o n of the h e m i c e l l u l o s e s and other f e r ­ m e n t a b l e c o m p o u n d s i n sulphite waste l i q u o r f o r p r o t e i n p r o d u c ­ tion, two c o m m e r c i a l i n s t a l l a t i o n s , both with a c a p a c i t y of 10 000 tons p e r annum, have gone into o p e r a t i o n . Metsàliiton Selluloosa in Àànekoski, produces fodder yeast f r o m b i r c h sulphite waste l i q u o r by a p p l i c a t i o n of the A t t i s h o l z p r o c e s s with T o r u l a y e a s t . T h e s e c o n d one, at U n i t e d P a p e r M i l l s , J â m s â n k o s k i m i l l site, i s b a s e d upon the P e k i l o p r o c e s s dev e l o p e d at the F i n n i s h P u l p and P a p e r R e s e a r c h Institute, and m a r k e t e d by the T a m p e l l a company. In the P e k i l o p r o c e s s , a c e t i c a c i d , h e x o s e s , pentoses and a l d o n i c a c i d s of the spent sulphite waste l i q u o r a r e f e r m e n t e d , and give r i s e to the P e k i l o m y c e l i u m . T h e f i b r o u s m u l t i c e l l s t r u c t u r e of the m y c e l i u m e n a b l e s i s o l a t i o n of the P e k i l o - p r o t e i n by s i m p l e f i l t r a t i o n . F o r this r e a s o n the r e q u i r e m e n t of w a s h - w a t e r i s v e r y s m a l l , with the c o n s e q u e n c e that the s e p a r a t i o n and w a s h i n g of the p r o d u c t does not i m p o s e a load upon the e n v i r o n m e n t . W h e r e a s p r o t e i n p r o d u c t i o n i s b a s e d upon the c a r b o h y d r a t e s of the spent sulphite l i q u o r , the l i g n i n c o m p o u n d s can s e r v e as a raw m a t e r i a l f o r a d h e s i v e s m a n u f a c t u r e . In i t s e l f , t h i s i s nothing new, and spent l i q u o r s have been u s e d f o r this p u r p o s e together with f e n o l f o r m a l d e h y d e r e s i n s . N o n e t h e l e s s , a new type of l i g n i n a d h e s i v e has been d e v e l o p e d at the F i n n i s h P u l p and P a p e r R e s e a r c h Institute. In this a d h e s i v e , l i g n i n der i v a t i v e s of h i g h m o l e c u l a r weight a r e c o p o l y m e r i s e d with f e n o l

168

CELLULOSE AND FIBER SCIENCE

f o r m a l d e h y d e r e s i n . T h i s a d h e s i v e , known c o m m e r c i a l l y as " K a r a t e x " , has b e e n t e s t e d f o r p l y w o o d and p a r t i c l e b o a r d g l u i n g , both i n the l a b o r a t o r y and i n f u l l s c a l e t r i a l s , at t h r e e F i n n i s h p l y w o o d m i l l s and one p a r t i c l e b o a r d m i l l . The r e s u l t s have o f f e r e d a g r e a t d e a l of p r o m i s e , and two F i n n i s h companies have a c q u i r e d the m a n u f a c t u r i n g r i g h t s . L i g n o s u l p h o n a t e s , with a m o l e c u l a r weight d i s t r i b u t i o n adequate f o r " K a r a t e x " a d h e s i v e , c a n e a s i l y be m a n u f a c t u r e d by an e c o n o m i c a l l y - a c c e p t a b l e p r o c e d u r e f r o m softwood spent sulphite l i q u o r , by m e a n s of u l t r a filtration. W i t h r e s p e c t to the u t i l i s a t i o n of b y p r o d u c t s f r o m the sulphate i n d u s t r y , one i n t e r e s t i n g d e v e l o p m e n t i s a p p a r e n t . T h e i n c r e a s e d u s e of b i r c h i n sulphate p u l p i n g has r e s u l t e d i n det e r i o r a t i o n i n q u a l i t y of the t a l l o i l . T h e m i x e d o i l cannot be u s e d d i r e c t f o r f u r t h e r r e f i n i n g . A p r o c e d u r e e v o l v e d at A b o A k a d e m i e n a b l e s i m p r o v e m e n t i n the q u a l i t y to the l e v e l of o r d i n a r y t a l l o i l by e x t r a c t i o n of the n e u t r a l m a t t e r . T h i s m e t h o d of c r u d e soap r e f i n i n g has p a s s e d the p i l o t p l a n t stage, and the f i r s t p r o d u c t i o n unit i s now i n c o u r s e of c o n s t r u c t i o n at the K a u k a s s u l p h a t e - p u l p m i l l . T h e t e c h n i c a l d e v e l o p m e n t work, and the e c o n o m i c s u r v e y s , have b e e n c a r r i e d out by the F i n n i s h f i r m L i n o t e k n o , and patent a p p l i c a t i o n s have been f i l e d i n F i n l a n d and a n u m b e r of other c o u n t r i e s . In the f i e l d of u t i l i s a t i o n of d i s s o l v i n g p u l p f o r v i s c o s e f i b r e p r o d u c t i o n an i n v e n t i o n m a d e s o m e y e a r s ago i s at p r e s e n t undergoing final m i l l t r i a l s . The SINI-viscose p r o c e s s a c c o r d ing to w h i c h a r e p e a t e d m e r c e r i s a t i o n with a l e s s c o n c e n t r a t e d s t e e p i n g l i q u o r and a p r e s s i n g i s c a r r i e d out i m m e d i a t e l y b e f o r e the xanthation i n o r d e r to d e c r e a s e the c a u s t i c content of the a l k a l i c e l l u l o s e , has as a c o n s e q u e n c e a 20 - 30 p e r cent r e d u c t i o n i n the c o n s u m p t i o n of the p r o c e s s c h e m i c a l s , c a r b o n d i s u l p h i d e , s o d i u m h y d r o x i d e and s u l p h u r i c a c i d , as c o m p a r e d w i t h the p r e s e n t p r o c e s s . M i l l t r i a l s c a r r i e d out i n two staple f i b r e and one c e l l o p h a n e m i l l have c o n f i r m e d the r e s u l t s and shown that the q u a l i t y of the p r o d u c t s r e m a i n s the s a m e o r e v e n i m p r o v e s somewhat. It s e e m s that the S I N I - p r o c e s s w h i c h r e q u i r e s investments, which are f a i r l y s m a l l c o m p a r e d with the advantages g a i n e d by r e d u c e d c h e m i c a l c o s t s and i m p r o v e d e n v i r o n m e n t a l c o n d i t i o n s , d u r i n g the next few y e a r s w i l l be taken into use i n s e v e r a l m i l l s . In this r e p o r t c o n c e r n e d with the t r e n d s i n the pulp and p a p e r i n d u s t r y , the m a i n i n t e r e s t has been d e v o t e d to p r o d u c t i o n p r o c e s s e s , and the p r o d u c t s obtained, but i t i s quite obvious that the F i n n i s h i n d u s t r y , j u s t as the i n d u s t r y i n other

7.

NORDMAN

Finnish Pulp and Paper Industry

169

c o u n t r i e s , i s c o n f r o n t e d by the r e q u i r e m e n t s of a c l e a n e r e n v i r o n m e n t . No attempt c a n be m a d e h e r e to p r e s e n t d e t a i l s of the m e a s u r e s that have been adopted, o r to r e c o r d the m i l l i o n s of F i n n m a r k s i n v e s t e d f o r the p r e v e n t i o n of w a t e r and a i r p o l l u t i o n . It i s s u f f i c i e n t to say that F i n n i s h p a p e r m a k e r s and s c i e n t i s t s a r e d e v o t i n g a g r e a t d e a l of t i m e to these p r o b l e m s . One a s p e c t of this i s d i s c e r n i b l e i n the i n t e r e s t i n r e s e a r c h r e l a t i n g to s u l p h u r l e s s pulping o r b l e a c h i n g , with p a r t of the b l e a c h i n g c h e m i c a l s b e i n g r e p l a c e d by oxygen. T h e r e i s one point i n r e l a t i o n to e n v i r o n m e n t a l r e s e a r c h I would l i k e to m e n t i o n . A n e x t r e m e l y i n t e r e s t i n g b i o l o g i c a l m e t h o d has been d e v e l o p e d f o r the p u r i f i c a t i o n of c o n d e n s a t e s f r o m the sulphate m i l l by the E n s o - G u t z e i t C o m p a n y . T h e d i f f e r e n c e between this m e t h o d and e a r l i e r u n s u c c e s s f u l a t t e m p t s at the a p p l i c a t i o n of b i o l o g i c a l t r e a t m e n t , l i e s i n the d i s c o v e r y of o p t i m a l c o n d i t i o n s f o r one p a r t i c u l a r s u l p h u r b a c t e r i a l s t r a i n , w h i c h not only w i t h s t a n d s , but i n f a c t d e m a n d s an e n v i r o n m e n t of t o x i c s u l p h u r c o m p o u n d s . T h e t r e a t m e n t plant c o m p r i s e two d i f f e r e n t f i l t e r u n i t s , one a l i q u i d and the other a gas f i l t e r ; i n e a c h c a s e , the f i l t e r i n g m a t e r i a l i s a bed p r e p a r e d f r o m softwood b a r k by a s p e c i a l m e t h o d . T h e condensates p a s s t h r o u g h the f i l t e r bed a g a i n s t an a i r s t r e a m . T h e f i l t e r e d w a t e r can be c o n d u c t e d into the water c o u r s e , w h e r e a s the a i r s t r e a m p a s s e s t h r o u g h a s e c o n d f i l t e r bed, f r o m w h e r e it c a n be l e d d i r e c t into the a t m o s p h e r e . T h e r u n n i n g c o s t s of the m e t h o d a r e d e c i s i v e l y l e s s than those i n v o l v e d i n c o m p e t i tive m e t h o d s , s u c h as s t r i p p i n g , s i n c e e n e r g y i s r e q u i r e d f o r the p u m p i n g of l i q u i d s and g a s e s only, but not at a l l f o r h e a t i n g or s t e a m g e n e r a t i o n .

Conclusions A n attempt to s u m m a r i s e t r e n d s i n the F i n n i s h p u l p and p a p e r i n d u s t r y c o u l d p e r h a p s take the f o l l o w i n g f o r m . 1) A p r e v i o u s , v e r y r a p i d i n c r e a s e i n the p r o d u c t i o n v o l u m e , has been s u p e r s e d e d by m o r e m o d e s t growth. 2) A shift i n the p r o d u c t i o n s c h e d u l e t o w a r d s p r o d u c t s of a h i g h e r d e g r e e of c o n v e r s i o n . 3) C o n f i d e n c e i n new m e c h a n i c a l p u l p i n g s y s t e m s , and a t r e n d t o w a r d s increases i n the p e r c e n t a g e of m e c h a n i c a l pulp i n different paper qualities. 4) A t t e m p t s to u t i l i s e the e n t i r e b i o m a s s of t r e e s f o r f i b r o u s and n o n f i b r o u s p r o d u c t s .

170

C E L L U L O S E A N D FIBER SCIENCE

F i n a l l y , although t h i s has not been e x p r e s s l y stated i n my presentation, t h e r e i s a v e r y s t r o n g w i s h , b a s e d upon our negative t r a d e b a l a n c e , that d o m e s t i c raw m a t e r i a l s , a d d i t i v e s and mac h i n e r y be u s e d to the g r e a t e s t extent p o s s i b l e . A n d of c o u r s e this i s c o u p l e d with a w i s h to s e l l to p a p e r m a k e r s throughout the w o r l d e q u i p m e n t and "know how" w h i c h has been a c q u i r e d w i t h i n a l l s e c t o r s of our own i n d u s t r y .