Recovery Boiler Replacement Optionswhitty/blackliquor/colloquium2006... · July 6, 2006 2 Replacement options Options for ageing recovery boiler • What to do if the technical age

July 6, 2006Replacement options1

Recovery Boiler Replacement Options

Esa Vakkilainen


Options for ageing recovery boiler

• What to do if the technical age of the recovery boiler is over• Buy a new boiler to replace old, e.g.

– Kaukas 1991 Gruvön 2000– Joutseno 1999 Värö 2002– Wisaforest 2004 Skoghall 2005

• Replace the furnace and add heating surface, e.g.– Wisaforest 1995 Skärblacka 1997– Veitsiluoto, Kemi 1999 Skutskär 2000– Äänekoski 2004 Bäckhammar 2001


Cumulative age of recovery boilers

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Rec

over

y bo

iler a

ge a

s ca

paci

ty o

f tot

al c

apac

ity, %

.

USASwedenFinlandBrazil


Startup year of recovery boilers

1950 - 591960 - 69

1970 - 791980 - 89

1990 - 992000 -

0

10000

20000

30000

40000

50000

60000

70000

80000

FinlandBrazilSwedenUSA


Age of recovery boilers – maximum 30 – 40 a

• Brazilian recovery boilers – Median age according to total capacity 12 a– 75 % is younger than 19 a– 10 % is older than 29 a

• Finnish recovery boilers – Median age according to total capacity 15 a– 75 % is younger than 28 a– 10 % is older than 35 a

• Swedish recovery boilers – Median age according to total capacity 29 a– 75 % is younger than 35 a– 10 % is older than 40 a

• Recovery boilers in USA– Median age according to total capacity 30 a– 75 % is younger than 36 a– 10 % is older than 41 a


Replaced recovery boiler is ~ 29 years when the new starts

0

5

10

15

20

25

30

35

40

45

50

1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

New boiler purchased

Rep

lace

men

t age


Additional capacity with new boiler ~ 1200 tds/d

0

500

1000

1500

2000

2500

3000

1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

New boiler purchased

Add

ition

al c

apac

ity, t

ds/d


Why choose large retrofit?

• When you need less than 20 % additional capacity• Investment 15 – 45 M€• Additional operating time needed only 10 – 15 a• Possible to stop production for 45 – 60 days• Need to decrease emissions -> new air system• Often accompanied by increase in dry solids


Why buy a new boiler?

• Need additional capacity over 40 %• Investment 100 – 200 M€• Replace two boilers with one -> production efficiency• Mill will be operating for 30 – 40 a• Maintenance stop only 3 – 7 days• Improved energy efficiency, more steam and power• Decrease emissions to air• Other replacements included (maintenance cost decreases)

– electrification– automation– auxiliary equipment


New boilers are bought with higher solids

50

55

60

65

70

75

80

85

90

1975 1980 1985 1990 1995 2000 2005 2010

Delivery year

Virg

in d

ry s

olid

s, %

Average

Maximum


Typical new project in Scandinavia

• Replaces two boilers– Götaverken 1976 1300 tds/d– Götaverken 1964 590 tds/d

• Age of replaced boilers at 2007 = 31 and 43 a (av. 37 a)– Pietarsaari 29 and 42 a (both had a major modernization)– Kaukas 20 and 27 a

• Addditional nominal capacity 2100 tds/d– Pietarsaari 2100 tds/d– Kaukas 1160 tds/d


There are peak periods of boiler purchases

0

2000

4000

6000

8000

10000

12000

14000

16000

1934

1937

1940

1943

1946

1949

1952

1955

1958

1961

1964

1967

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

Year

Rec

over

y bo

iler c

apac

ity s

old,

tds/

d

Past 5 year USA averagePast 5 years Sweden averagePast 5 years Finland average


There are peak periods of boiler purchases

• Almost no new projects at US after’93

• Sweden replaces at rather flat rateof 1000 tds/d, except during the recession after ’91

• Finland had a peak in the beginning of 90’s that levelled to the same 1000 tds/d

0

1000

2000

3000

4000

5000

6000

7000

1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

YearR

ecov

ery

boile

r cap

acity

sol

d, td

s/d Past 5 year USA average

Past 5 years Finland averagePast 5 years Sweden average


World black liquor processing capacity keeps growing

0

20

40

60

80

100

120

140

160

180

200

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Bla

ck li

quor

pro

duct

ion

, 10^

6 td

s/a

World


Changes in pulp production

1000 tds/d to recovery boiler means ~200 000 ADt/a-4000000

-2000000

0

2000000

4000000

6000000

8000000

1990 1992 1994 1996 1998 2000 2002 2004 2006

Cha

nge

in p

ulp

prod

uctio

n (r

ef =

199

1), t

Finland Sweden United States of America


Changes in pulp production – global view

1000 tds/d to recovery boiler means ~200 000 ADt/a-4000000

-2000000

0

2000000

4000000

6000000

8000000

1992 1994 1996 1998 2000 2002 2004 2006

Cha

nge

in p

ulp

prod

uctio

n (r

ef =

199

3), t

Indonesia Brazil Finland Canada Sweden United States of America


As units get bigger the number of units decreases

0

5

10

15

20

25

30

35

40

1934

1936

1938

1940

1942

1944

1946

1948

1950

1952

1954

1956

1958

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

Year

Num

ber o

f uni

ts s

old

Each year Past 5 year average)


Market share of recovery boiler capacity sold*

*Excluding former soviet block and China

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

1934

1937

1940

1943

1946

1949

1952

1955

1958

1961

1964

1967

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

Year

Rec

over

y bo

iler m

arke

t sha

re

(cap

acity

sol

d, td

s/d)

Past 5 years KvaernerPast 5 years Andritz Past 5 years Japanese averagePast 5 years CE and B&W average


Single drum boilers

• All recovery boilers used to be two drum design. One of the main reasons to move to single drum design was the size of the boilers. Tube stiffness limits cross flow two drum arrangement to about 2300 tds/d size and vertical flow two drum constructions have suffered from plugging because of vibration stiffeners.

• The first modern single drum recovery boiler was delivered in 1984 by Götaverken to Leaf River, the boiler size was1966 tds/d, By 1990 all manufactures started to provide single drum boilers and excluding very small ones, all modern boilers are now single drum design.


Advantages of single drum construction:

• Single drum construction eliminates the possibility of water leakage to furnace as it is placed outside the furnace.

• There are significantly less holes in drum wall, which can be built thinner.

• Thinner wall of drum allows faster start-up and shut-down.• The gas flow to the boiler bank is smoother and heating surface

arrangement is simple.• The erection period is shorter because of large block construction.

There is no rolled tube work.• The water circulation in the boiler is enhanced and steady due to

separated and unheated downcomers.


Old two drum – replaced with modern single drum

• Lower furnace needed replacement

• Two drum boiler bank was old• Vertical flow offered increased

capacity• Increase in dry solids


Summary

• 30 years means need to replace the recovery boiler• 20 years is typical replacement age if mill capacity is increased• Single drum conversion is fairly typical

• “Recovery boiler improvements do not guarantee mill viability” (Jim Rowland, Canadian Paper Analyst)

Recovery Boiler Replacement Optionswhitty/blackliquor/colloquium2006... · July 6, 2006 2 Replacement options Options for ageing recovery boiler • What to do if the technical age

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