Modified Alkaline Pulping Integrated with Hemicellulose

40 Pages·2009·0.3 MB·English

2009 TAPPI EPE
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Outline
(cid:131) Objectives
(cid:131) Problem Statements
(cid:131) Process Design
(cid:131) Experimental
(cid:131) Results
(cid:131) Phase 1: Extraction-Yield Relationship
(cid:131) Phase 2: Yield Preservation & Mass Balance
(cid:131) Phase 3: Papermaking Properties
(cid:131) Conclusions
SW Sugar Extraction Effectiveness Test
(Unpublished Data)
14
W
12
D
O

n
o 10
% Water Extraction

,
d
e 8
t
c
a
r
t
x
6
E

s
r
a
g 4 4% Sodium Sulfite Extraction
u
S

l
a
t
o 2
T
4% Green Liquor Extraction
0
0 5 10 15 20 25
Weight Loss, % on ODW
Water Extraction Effect on Pulp Yield
(Published by Yoon et. al., Tappi J. July 2008 )
65
60
W
D
O
55

n
o

%
50

,
d
l
e
i
Y 45

p
l
u
P 40
SWX200H(15%EA)

l
a SWX500H(15%EA)
t
o CONTROL-1(15%EA)
T 35
CONTROL-2(17%EA)
30
0 20 40 60 80 100 120 140 160
Pulp Kappa Number
Tensile Strength (from Published Data )
65
60
g 55
/
2
m
* 50
m
/
N
45

,
x
e
d 40
n
I

e
l 35
i
s
n SXW400H-1(15%EA;19KAPPA)
e
30
T SXW400H-2(15%EA;44KAPPA)
CONTROL-1(17%EA;23KAPPA)
25
CONTROL-2(17%EA;25KAPPA)
20
100 300 500 700
Degree of PFI Refining, CSF(mls)
Problem Statement
- Promising Effects in Hemicellulose
Extraction with Water
- Sizable Reduction in Kraft Pulp Yield
- Significant Reduction in Paper Strength
Objectives
To evolve existing chemical pulp mills
into Integrated Forest Products Bio-refineries
(IFBR) for production of new biomaterials
and renewable bio-energy:
- Develop an effective process for extracting
hemicelluloses from wood chips prior to pulping
- Develop a modified pulping process preceded by
hemicellulose extraction that maintains yield and
quality of pulp (Critical !!)
Approach to Yield Preservation
Reductive Pretreatment for carbohydrate
stabilization against alkaline peeing
• Reducing Agents:
– Na S (ASS)
2
– Sodium Borohydride (SBH)
Equilibrium Diagram for Composition of the Kraft White
Liquor at Different pH values
pH
0 2 4 6 8 10 12 14
- 1
-
H S HS
2
]
)
3
m
d
/
l
o
m +
H
(
n- 3
o
i
t
a 2-
S
r
t
n
e
-
c OH
n
o
C
- 5
[
g
o
L
- 7
End Groups Stabilization of
Carbohydrates with H S Reduc ing Agent
2
+ -
H , HS - H O, H S
2 2
R- CHO R- CH(OH)SH
(Aldehyde End Group)
H S
- H S 2
2 R- CH SH
R- CH(SH) R- CHO 2
2 - S
(Thioalditol)
Eero Sjostrom, Wood Chemistry, 2nd Ed.,p155