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In a TCF (Totally Chlorine-free) bleaching sequence, chlorine dioxide can be used as a
bleaching agent
False
What is the primary purpose of oxygen delignification in the pulp production process?
To selectively remove lignin while preserving pulp yield.
Global production of pulp sourced from non-wood biomass has decreased since 2010
True
What percentage of global pulp production in 2022 was attributed to chemical pulp?
79.6%
What are the structural differences between softwood and hardwood fibers?
Softwood are longer and have greater strength while hardwood are longer with less strength
When would you choose to use softwood/hardwood fibers? What properties do they create in paper made with them?
Softwood = Use in applications requiring high strength
Hardwood = Smoothness, Opacity, used in many specialty papers and magazine/newspaper
What are the disadvantages/benefits to using non-wood fiber sources?
Disadvantages include lack of supply chain and processing difficulties
Benefits include lower cost and easier access in certain environmentsWhat part of the tree contains the strongest/most commonly used fibers?
What part of the tree contains the strongest/most commonly used fibers?
Heartwood
Put the following terms in the order they occur in the drying and baling process: Wet end, dryer, cutter layboy, bailing
Wet end, dryer, cutter, bailing
Why would a plant choose to bale pulp rather than storing it as sheets?
So it can be cut later into specific shapes for specific purposes
Name at least three of the five main reasons why debarking is critical for woodprocessing and provide an explanation for each reason
a. Low Yield of Fiber from Bark (Only about 20% of fiber is usable per slides)
b. Potential Equipment Damage (Particulates found in bark like sand)
c. High Extractives Content (Requires more processing chemicals)
d. Drainage Obstacles (Small cells in bark can inhibit dewatering)
e. Dirty Paper (Some bark cells will not degrade, and will appear as dirt-like
What are the benefits of implementing a recovery boiler within the wood handling
process?
a. Reduces waste
b. Produces usable energy
A
Acid Wash
C
Chlorine Gas
E
Alkaline Extraction
Q
Celating Agent
Y
Dithionite
When is Oxygen Delignification used in the Bleaching process?
First Stages of the Bleaching Process
Briefly explain one reason why Oxygen Delignification is preferred over other
methods of delignification
More selective cooking to reduce Kappa number without degrading fibers
Explain the difference between TCF and ECF in the pulp bleaching process
ECF = Elemental Chlorine Free (Chlorine Dioxide can be used)
TCF = Totally Chlorine Free
List a primary and secondary goal of the pulp bleaching process
a. Primary: Bright paper product
b. Secondary: Stable brightness, Clean Pulp
What is the ideal pH of a bleaching chemical? Explain why.
The ideal pH of a bleaching chemical is alkaline (high pH). An alkaline solution is best
because alkaline conditions aid in dissolving and removing lignin
Briefly explain the floatation deinking process.
Air bubbles are injected into the pulp in a floatation cell. With the aid of certain chemicals,
the ink particles attach to the air bubbles and rise to the surface where they can be skimmed off.
Briefly explain the washing deinking process
The small ink particles are separated from the fiber suspension by the use of wires or
screens.
As the Kappa number increases the lignin content…
increases
As the pulp viscosity decreases, the degree of polymerization…
Decreases
White Liquor mainly consists of…
NaOH and Na2S
