Review of Oxygen Review of Oxygen Delignification to Offload Kraft ...
Review of Oxygen Delignification to Offload Kraft Pulping Lucian A A. Lucia1 T. J. Dyer,2 D. Johnston,2 A.J. Ragauskas2 1North
Carolina State University 2Georgia g Institute of Technology gy
Oxygen Delignification •
Evolution of oxygen delignification technology: – 1970-1983: high consistency – 1983-1996: 1983 1996: medium – 1996-present: two sstage age OxyTrac O y acTM
Key: Improved environmental and operating cost performance
Wo d daily World d y production p oduc o of o oxygen delignified pulp
Oxygen Delignification Background Literature • 1960/70s – basic engineering & chemistry • 1980/early 90s – process parameters, energy, environmental pretreatments environmental, pretreatments, fundamental chemistry, pulp properties • Late 1990 1990’ss – yield, selectivity, process parameters, lignin/carbohydrate chemistry chemistry, catalysts
O gen Delignification Oxygen
Pulp Yieeld, %.
Increased interest in one and two-stage two stage oxygen delignification 50 49 48 47 46 45 44 43 42 41 40 39 38
Kraft
0
10
20
30
KAPPA
40
50
Yield and Operating Benefits
60
An Alternative Approach • Mini-O – Removes less lignin – Less capital – Easily retrofitted
• Enhanced Mini-O – Greater lignin removal – Multiple M l i l stages – H2O2 and/or ClO2
Mill Application • McKenzie – Cook to normal target • Reduce lignin with O2
– Sodium hydroxide instead stead of o oxidized o d ed white liquor
• Low AOX pulps – No production loss – No recovery bottleneck – 25% delignification
Recent Studies • Chakar, et al.
30
– Compared O systems y
25
• O, OO, mini-O
Kappa #
20 15
– Split the caustic charge in a (E+O)D(E+O)
10
– Delignification • Lowest for mini-O (E+O ) (E+O – 13-25%, 13-25% )D((E +O ) depending on O caustic OO addition
5 0 BS O Na
H
% .5 1 : O Na
H
% .5 2 : O Na
H
% .5 3 :
Recent Studies • Chakar, et al.
30
– Viscosities
25 Viscoosity/cP
• O vs. (E+O)D(E+O) 20
– Same delignification at 3.5% as O at 1.5%
15
• Improved viscosity
10 (E+O)D(E+O)
5
OO O
0
w Lo
a pp a K
BS
BS L
% .5 1 -
% .5 2 L-
% .5 3 L-
Recent Studies • Chakar, et al. – Does not mimic actual bl h plant bleach l t conditions diti – Need to investigate impact of interstage washing and carryover on mini-O i i O system
Mini-O Mini O Delignification Studies Research Objective j • Examine impact of carryover • 26.3 26 3 Kappa SW kraft • Determine – Physical properties – Selectivity • Contribute C ib to future f mini i i O-delignification O d li ifi i performance f
Mi i O D Mini-O Delignification: li ifi i Experimental E i l Design D i Bleaching Sequences
BL Carryover
• • • •
• No carryover • 2 kg/ton • 10 kg/ton
(E+O)(E+O) D(E+O) (E+O)D(E+O) ( )( ) D(E+O)(E+O)
E Experimental i l Conditions C di i St Stage
OP O-Press./psi / i %N NaOH OH
(E+O) D0.05, 0.20 (E+O)D(E+O)
10% consistency MgSO4: 0.10%
Temp.//oC Time/min. T Ti / i
90
1.25
80
20
-
-
70
30
90/0/90
1.25/0/1.25
80/70/80
70
Impact of Carryover 100
•
Carryover decreases delignification
•
Increased levels
% De elignificatio n
90 80 70
– Decreased response
60 50 40
(E +O
D0
.2
0(
E+ O) (E +O )D 0. ) 20 (E +O D0 ) .2 D0 0( E+ .0 5( O) E+ O) (E +O (E +O )D ) 0. 05 (E +O D0 ) .0 5( E+ O) (E +O )(E +O )
30
• no carryover 2 kg/ton 10 kg/ton
Splitting (E+O) – Improved response
Impact of Carryover •
% Vis scosity L Loss
35
25
•
20
Carryover – May introduce transition metals
15
0 (E (E+ +O O )D )(E + 0. 20 O) ( D D0 E+O . 0. ) 05 20( E + (E (E+ O O) +O )(E )D +O 0. 05 ) ( E+ D 0. 05 O) (E (E +O +O ) )(E +O )
0. 2
– Increases as function of carryover
30
10
D
Viscosity loss
10 kg 2 kg/ /ton no ca ton rryov er
•
Placement of (E+O) – Affects viscosity loss
Impact of Carryover S electivity
6
•
Selectivity – Decreases as function of carryover
5 4 3
•
2 1
D0 .2 0 (E (E+ +O O )D ) (E + 0. 2 0 O) (E +O D0 D0 . 2 ) .0 5( 0(E E +O (E +O +O) ) ( E+ )D 0. 0 5 O) D0 (E+ O .0 5( ) E+ (E O +O ) )(E +O )
0
no c 2 k ar ry o g/ v 10 ton e r kg /to n
Carryover – May introduce transition metals
•
Placement of (E+O) – Affects selectivity
Mini-O Mini O Delignification: Implications • Potential low capital retrofit technology to enhance pulping technology • Benefits of enhanced poor man’s O
Thanks to DOE for support And you for your attention!
Carolina State University 2Georgia g Institute of Technology gy
Oxygen Delignification •
Evolution of oxygen delignification technology: – 1970-1983: high consistency – 1983-1996: 1983 1996: medium – 1996-present: two sstage age OxyTrac O y acTM
Key: Improved environmental and operating cost performance
Wo d daily World d y production p oduc o of o oxygen delignified pulp
Oxygen Delignification Background Literature • 1960/70s – basic engineering & chemistry • 1980/early 90s – process parameters, energy, environmental pretreatments environmental, pretreatments, fundamental chemistry, pulp properties • Late 1990 1990’ss – yield, selectivity, process parameters, lignin/carbohydrate chemistry chemistry, catalysts
O gen Delignification Oxygen
Pulp Yieeld, %.
Increased interest in one and two-stage two stage oxygen delignification 50 49 48 47 46 45 44 43 42 41 40 39 38
Kraft
0
10
20
30
KAPPA
40
50
Yield and Operating Benefits
60
An Alternative Approach • Mini-O – Removes less lignin – Less capital – Easily retrofitted
• Enhanced Mini-O – Greater lignin removal – Multiple M l i l stages – H2O2 and/or ClO2
Mill Application • McKenzie – Cook to normal target • Reduce lignin with O2
– Sodium hydroxide instead stead of o oxidized o d ed white liquor
• Low AOX pulps – No production loss – No recovery bottleneck – 25% delignification
Recent Studies • Chakar, et al.
30
– Compared O systems y
25
• O, OO, mini-O
Kappa #
20 15
– Split the caustic charge in a (E+O)D(E+O)
10
– Delignification • Lowest for mini-O (E+O ) (E+O – 13-25%, 13-25% )D((E +O ) depending on O caustic OO addition
5 0 BS O Na
H
% .5 1 : O Na
H
% .5 2 : O Na
H
% .5 3 :
Recent Studies • Chakar, et al.
30
– Viscosities
25 Viscoosity/cP
• O vs. (E+O)D(E+O) 20
– Same delignification at 3.5% as O at 1.5%
15
• Improved viscosity
10 (E+O)D(E+O)
5
OO O
0
w Lo
a pp a K
BS
BS L
% .5 1 -
% .5 2 L-
% .5 3 L-
Recent Studies • Chakar, et al. – Does not mimic actual bl h plant bleach l t conditions diti – Need to investigate impact of interstage washing and carryover on mini-O i i O system
Mini-O Mini O Delignification Studies Research Objective j • Examine impact of carryover • 26.3 26 3 Kappa SW kraft • Determine – Physical properties – Selectivity • Contribute C ib to future f mini i i O-delignification O d li ifi i performance f
Mi i O D Mini-O Delignification: li ifi i Experimental E i l Design D i Bleaching Sequences
BL Carryover
• • • •
• No carryover • 2 kg/ton • 10 kg/ton
(E+O)(E+O) D(E+O) (E+O)D(E+O) ( )( ) D(E+O)(E+O)
E Experimental i l Conditions C di i St Stage
OP O-Press./psi / i %N NaOH OH
(E+O) D0.05, 0.20 (E+O)D(E+O)
10% consistency MgSO4: 0.10%
Temp.//oC Time/min. T Ti / i
90
1.25
80
20
-
-
70
30
90/0/90
1.25/0/1.25
80/70/80
70
Impact of Carryover 100
•
Carryover decreases delignification
•
Increased levels
% De elignificatio n
90 80 70
– Decreased response
60 50 40
(E +O
D0
.2
0(
E+ O) (E +O )D 0. ) 20 (E +O D0 ) .2 D0 0( E+ .0 5( O) E+ O) (E +O (E +O )D ) 0. 05 (E +O D0 ) .0 5( E+ O) (E +O )(E +O )
30
• no carryover 2 kg/ton 10 kg/ton
Splitting (E+O) – Improved response
Impact of Carryover •
% Vis scosity L Loss
35
25
•
20
Carryover – May introduce transition metals
15
0 (E (E+ +O O )D )(E + 0. 20 O) ( D D0 E+O . 0. ) 05 20( E + (E (E+ O O) +O )(E )D +O 0. 05 ) ( E+ D 0. 05 O) (E (E +O +O ) )(E +O )
0. 2
– Increases as function of carryover
30
10
D
Viscosity loss
10 kg 2 kg/ /ton no ca ton rryov er
•
Placement of (E+O) – Affects viscosity loss
Impact of Carryover S electivity
6
•
Selectivity – Decreases as function of carryover
5 4 3
•
2 1
D0 .2 0 (E (E+ +O O )D ) (E + 0. 2 0 O) (E +O D0 D0 . 2 ) .0 5( 0(E E +O (E +O +O) ) ( E+ )D 0. 0 5 O) D0 (E+ O .0 5( ) E+ (E O +O ) )(E +O )
0
no c 2 k ar ry o g/ v 10 ton e r kg /to n
Carryover – May introduce transition metals
•
Placement of (E+O) – Affects selectivity
Mini-O Mini O Delignification: Implications • Potential low capital retrofit technology to enhance pulping technology • Benefits of enhanced poor man’s O
Thanks to DOE for support And you for your attention!
