CPB 201 EXAM 2 STUDY GUIDE
Oxidize - Answers :Add O2
Reduction reaction - Answers :subtract O2 by burning the substance with C to get CO2
Active Alkali (AA) - Answers :NaOH, Na2S,Na2SO3, etc (anything with Na)
Na2S+H2O produces - Answers :NaOH+NaHS
Effective Alkali (EA) - Answers :NaOH+1/2Na2S
Sulfidity - Answers :(Na2S/(NaOH+Na2S))*100
Causticity - Answers :(NaOH/(NaOH+Na2S))*100
100% NaOH - Answers :has poor selectivity
100% Na2S - Answers :Nothing really happens
Chemical Pulping Objectives - Answers :1) to liberate fibers by removing the lignin in
the middle lamellae
2) remove lignin from the cell wall
Natural penetration vs forced penetration - Answers :wetting vs pressure or vacuum
release (insta pot ~ batch digester)
Chemical Pulping Methods - Answers :Soda, sulfite, kraft
Neutral sulfite semichemical - box medium
Organosolve solvent pulping = VOC
Extractives are used to make - Answers :paint thinner
Brightness wavelength - Answers :457
Delignification - Answers :beaking down the chemical structure of lignin and rendering it
soluble in liquid (using SO3-)
Delignification Selectivity - Answers :the ability to remove lignin without degrading the
holocelluloses
Dissolving Pulp - Answers :Low yield (only cellulose left) - rayon
Kappa Number - Answers :a measure of the lignin content of pulp
% lignin*5=Kappa number
, Pulp viscosity - Answers :average chain length of glucose and polymers
Higher viscosity means higher pulp viscosity
Chemical Properties - Answers :high strength
more flexible
fiber length has little effect on density (not filling in holes with fines like MP since it is
already as dense as possible due to flexibility)
Kraft Properties - Answers :Strongest fibers
Sulfite properties - Answers :weaker fibers
more easily beaten
box medium
Sulfite Pulping - Answers :Acid (SO3) - Bisulfite (HSO3-) is used to tone down the acid
so it only attacks the lignin
Creates an INsoluable lignosulfonic acid so insert NaS to make it soluble
The base is needed to buffer to prevent "burned cook"
Calcium salts create limestone - bad for pipes so they prefer Na2CO3 (soda ash) or
NH4OH (ammonia)
Bisulfite pH - Answers :pH 3-5
Neutral Sulfite pH - Answers :pH 5-10 - high yield (65-85%) and usually hardwood
Chemithermomechanical pulp STMP) pH - Answers :Acid pulping - strongest of all
pulping
Used in Canada
Kraft Process - Answers :Na2SO4+2C -> NaS+2CO2 - in a reducing atmosphere
Na2S+H2O -> {(NaHS)+NaOH}- fights lignin, slows condensation, protects cellulose
Cooking Liqours - Answers :White liquor, Black liquor, and Green liquor
White Liqour - Answers :Fresh pulping liquor containing reactants
NaOH and Na2S and residual Na2CO3 from the recovery process
Black Liqour - Answers :Waste liquor from the kraft process. It contains the original
cooking reactants and the dissolved wood substances.
Green Liqour - Answers :Partially recovered from Kraft liqour
Obtained by dissolving the smelt from the recovery boiler after combustion of the black
liqour
reacted with quick lime (CaO) to form white liquor
Na2CO3 and Na2S
Oxidize - Answers :Add O2
Reduction reaction - Answers :subtract O2 by burning the substance with C to get CO2
Active Alkali (AA) - Answers :NaOH, Na2S,Na2SO3, etc (anything with Na)
Na2S+H2O produces - Answers :NaOH+NaHS
Effective Alkali (EA) - Answers :NaOH+1/2Na2S
Sulfidity - Answers :(Na2S/(NaOH+Na2S))*100
Causticity - Answers :(NaOH/(NaOH+Na2S))*100
100% NaOH - Answers :has poor selectivity
100% Na2S - Answers :Nothing really happens
Chemical Pulping Objectives - Answers :1) to liberate fibers by removing the lignin in
the middle lamellae
2) remove lignin from the cell wall
Natural penetration vs forced penetration - Answers :wetting vs pressure or vacuum
release (insta pot ~ batch digester)
Chemical Pulping Methods - Answers :Soda, sulfite, kraft
Neutral sulfite semichemical - box medium
Organosolve solvent pulping = VOC
Extractives are used to make - Answers :paint thinner
Brightness wavelength - Answers :457
Delignification - Answers :beaking down the chemical structure of lignin and rendering it
soluble in liquid (using SO3-)
Delignification Selectivity - Answers :the ability to remove lignin without degrading the
holocelluloses
Dissolving Pulp - Answers :Low yield (only cellulose left) - rayon
Kappa Number - Answers :a measure of the lignin content of pulp
% lignin*5=Kappa number
, Pulp viscosity - Answers :average chain length of glucose and polymers
Higher viscosity means higher pulp viscosity
Chemical Properties - Answers :high strength
more flexible
fiber length has little effect on density (not filling in holes with fines like MP since it is
already as dense as possible due to flexibility)
Kraft Properties - Answers :Strongest fibers
Sulfite properties - Answers :weaker fibers
more easily beaten
box medium
Sulfite Pulping - Answers :Acid (SO3) - Bisulfite (HSO3-) is used to tone down the acid
so it only attacks the lignin
Creates an INsoluable lignosulfonic acid so insert NaS to make it soluble
The base is needed to buffer to prevent "burned cook"
Calcium salts create limestone - bad for pipes so they prefer Na2CO3 (soda ash) or
NH4OH (ammonia)
Bisulfite pH - Answers :pH 3-5
Neutral Sulfite pH - Answers :pH 5-10 - high yield (65-85%) and usually hardwood
Chemithermomechanical pulp STMP) pH - Answers :Acid pulping - strongest of all
pulping
Used in Canada
Kraft Process - Answers :Na2SO4+2C -> NaS+2CO2 - in a reducing atmosphere
Na2S+H2O -> {(NaHS)+NaOH}- fights lignin, slows condensation, protects cellulose
Cooking Liqours - Answers :White liquor, Black liquor, and Green liquor
White Liqour - Answers :Fresh pulping liquor containing reactants
NaOH and Na2S and residual Na2CO3 from the recovery process
Black Liqour - Answers :Waste liquor from the kraft process. It contains the original
cooking reactants and the dissolved wood substances.
Green Liqour - Answers :Partially recovered from Kraft liqour
Obtained by dissolving the smelt from the recovery boiler after combustion of the black
liqour
reacted with quick lime (CaO) to form white liquor
Na2CO3 and Na2S
