[Topic 7] Pulp and Paper Industry Flashcards
Main structural polysaccharide of the plant cell wall.
Cellulose [(C6H5O10)n]
Made from fibrous material and usually in thin flat sheets.
Paper
A plant source for papyrus
Cyperus papyrus
Inventor of the printing press
Johaness Gutenberg
Three main types of pulp processing (3)
- Chemical
- Semi-chemical
- Mechanical/Thermomechanical
Raw materials for pulp processing (3)
- Wood fibers
- Cotton and linen rags
- Other applicable fibrous material
Soft wood
coniferous
Hard wood
deciduous
Conversion of wood into mass of liberated fibers
Pulping
Types of chemical pulping (3)
- Kraft (Sulfate) Process
- Soda Process
- Sulfite Process
meaning of the german word kraft
Strong
uses Na2SO4 and NaOH to pulp wood and can produce odoriferous chemicals during liquor cooking.
Kraft (Sulfate) Process
Is an essential factor of the Kraft Process
Black (spent) liquor recovery
True or false: Kraft process contains 95-98% of the total chemicals removed during cooking of the liquor.
True
Uses either Na2CO3 or Na2SO4 in cooking liquor.
Soda Process
It worked well only with deciduous (hard) wood.
Soda Process
Similar to Kraft Process but uses different chemicals in cooking liquor.
Sulfite Process
Sulfurous acid (H2SO3) is used instead of caustic (NaOH) solutions
Sulfite Process
Most common raw materials in sulfite process
Spruce
Primary waste product in sulfite process
Waste sulfite liquor
Process Flow of Kraft Process
Woodyard Section > Pulp Processing Section > Bleaching Section > Paper Processing Section > Liquor Recovery Section
In the pulp processing section, Na2SO4 is added to the white liquor, which was composed of Ca(OH)2 and NaOH created through _____________ .
Causticization
Resulting liquor in pulp processing section
Black liquor
Used for pre-bleaching
Chlorine gas (Cl2)
It reduces Kappa Number
Sodium hydroxide (NaOH) treatment
dimensionless number that measures the lignin content of pulp
Kappa Number
Kappa number for paper
K < 5.00
Main chemical used in bleaching
Chlorine dioxide (ClO2)
Used in pulp refining in the paper processing section.
Jordan Machine
It delivers a uniform pulp slurry on the conveyor wires.
Headbox
large amounts of dewatering
Rolling press
Effectively remove moisture left after pressing
Dryers
a dilute, white stock solution of hot water and fibers.
White water
Four main sections of Fourdrinier Machine (4)
- Wet end section
- Wet press section
- Dryer section
- Calendar/Ironing section
Black liquor is removed from washing of the pulp.
Liquor recovery section
This is produced in the liquor recovery section to be added with Na2SO4 for cooking chipped wood.
White cooking liquor
Two principal types of reaction in the sulfite process (2)
- Sulfonation and solubilization of lignin by the bisulfite ion
- Hydrolytic splitting of the cellulose-lignin complex
The ______ from the Kraft Process can also be used as a cooking medium in neutral sulfite process.
Green liquor
Type of semi-chemical pulping (1)
- Neutral Sulfite Process
Pulp yields are usually at 65-80% compared to 50-55% for chemical pulping.
Semi-chemical pulping (Neutral sulfite)
Absence of chemical treatment
mechanical pulping
Uses HPHT to soften the lignin and make mechanical pulping more efficient.
Thermomechanical pulping
Other Pulping Processes (4)
- Solvent Pulping
- Secondary Fiber Pulping
- Rag Pulping
- Dissolving Pulping
other term for secondary fiber pulping
Recycled Fiber Pulping
Used cotton as raw material
Rag pulping
Post-treatment of high-quality sulfite pulp with NaOH
Dissolving Pulp
Two Main Types of Paper manufacturing
- Wet Processes
- Dry Processes
Two general processes of wet process
- Beating
- Refining
Equipment used to beat plant fiber to make the paper stronger and more uniform.
Hollander Beater
Used in pulp refining, deforming, defibering, and dispersing without cutting.
Jordan Engine (Conical Refiner)
Other machine used in wet process.
Fourdrinier Machine
Used because wet process is expensive and has complex equipment
Dry Process
Also called as specialty papers
Coated papers
Coating with a substance to produce specialty papers.
Sizing