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You are here : Home > Training > EFPG Days > 6- Effect of wood species mixtures on Kraft pulping (slides 9-16)
        Last update : July 22, 2003
 
                  Second Session : The yield issue                   
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  Logo EFPG     VI - Effect of wood species mixtures on Kraft pulping (slides 9-16)

Christine Deleuze, Denilson Da Silva Perez, Michaël Lecourt (AFOCEL)
 
 
9 - Application to pulp and paper technology
    Softwood or hardwood mixture in kraft cooking
  Hardwood species:   Softwood species:
Beach + Poplar Douglas + Norway Spruce
Oak
Chestnut
Scot Pine
Maritime Pine
  Properties analyzed: pulp yield
 
 
10 - Pulp Yield: Hardwood mixtures
Mix: Beech + Poplar
Oak                 Chestnut
PYield18 = 53.89 P + 52.34 B + 46.35 O
+ 7.72 P*B + 6.58 P*O + 8.15 H*O
PYield18 = 83.92 P + 52.18 B + 46.35 C
 
74% variability explained 67% variability explained
Kappa = 18
 
 
11 - Pulp Yield: Softwood mixtures
Mix: Douglas + Norway Spruce
Scott Pine                 Maritime Pine
PYield = 15 + 4.1*(7.3932 SP + 8.0449 DO
+ 8.9802 NS + 3.4947 SP*DO
- 1.9631 SP*NS + 1.0334 DO*NS)
PYield = 15 + 4.1*(7.050 MP + 8.0449 DO
+ 8.9802 NS - 0.4251 MP*DO
+ 3.0598 MP*NS + 1.0334 DO*NS)
82.14% variability explained 82.14% variability explained
Kappa = 40
 
 
12 - Addition of 10% of Scott or Maritime Pine
Evolution of pulp yield for a mix constituted of 10% pine and 90% of different proportions in Douglas
and Norway Spruce
 
 
13 - Other measured properties
  Fibers morphology
  Paper properties:
    Physical properties
  COD / BO
  Process parameters:
  Liquor consumption
   
14 - Evolution of morphological properties
Maritime Pine - Douglas - Norway Spruce
Variable Variance
explained
Model equation Best
proportions
Fibre length
(µm)
56.53% 2348.65 NS+2280.65 DO
+ 2165.9 MP
Spruce
Fibre width
(µm)
92.10% 34.6644 NS +32.05021 DO +
37.89889 MP + 3.12793 NS*DO
-3.2067 EP*MP+2.36293 DO*MP
Maritime
Pine
Coarseness
(mg/m)
84.81% 0.27252 NS + 0.2782 DO +
0 .36156 MP + .22143 NS*DO +
.20616 NS*MP + .08152 DO*MP
- 1.39924 NS*DO*MP
30% NSpruce
70% Mar. Pine
 
 
15 - Outlooks
  Impact of sample origin:
  Country
  Storage conditions
  Applications to Kraft cooking & to TMP process:
  Energy saving
  Use of new mixtures
   
16 - Conclusions
  Scheffé Diagram
  Fast method, simple
  Graphic representation
  BUT results highly influenced by sampling method
  Results: better pulp and paper properties
  Pulp yield
  Paper physical properties
  Pulp fibers morphological properties
  Possibility of other models forms based on physical or chemical theory and knowledge
 
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