Category: Pulp & Paper Objective Questions

Pulp and Paper Interview Questions and Answers on “Related Pulping Methods”.

1. The Asplund process was developed about 30 years prior to TMP.
a) True
b) False
Answer: a
Clarification: The Asplund process was developed about 30 years prior to TMP.

2. Asplund process involves pre-steaming wood chips at temperature above the glass transition temperature of lignin.
a) True
b) False
Answer: a
Clarification: The Asplund process was developed about 30 years prior to TMP. It involves pre-steaming wood chips at temperature above the glass transition temperature of lignin. 550-950 kPa steam pressureat 150-170 degree Celcius.

3. What is the pressure range at which the wood chips are pre-streamed?
a) 1300-1950 kPa
b) 550-950 kPa
c) 42-78 kPa
d) 1285-1950 kPa
Answer: b
Clarification: The Asplund process was developed about 30 years prior to TMP. It involves pre-steaming wood chips at temperature above the glass transition temperature of lignin. 550-950 kPa steam pressureat 150-170 degree Celcius.

4. What is the steam pressure range at which the wood chips are pre-heated?
a) 50-200 degree celcius
b) 300-340 degree celcius
c) 1500-2000 degree celcius
d) 150-170 degree celcius
Answer: d
Clarification: The Asplund process was developed about 30 years prior to TMP. It involves pre-steaming wood chips at temperature above the glass transition temperature of lignin. 550-950 kPa steam pressure at 150-170 degree Celcius.

5. The lignin is sufficiently soft that the separation occurs at __ lamella, and fibers are left with just a hard lignin surface.
a) Upper
b) Lower
c) Middle
d) Outskirt
Answer: c
Clarification: The lignin is sufficiently soft that separation occurs at the middle lamella, and fibers are left with a hard lignin surface.

6. What is the other name of Masonite process?
a) Ignition process
b) Steam explosion
c) Mason process
d) TMP
Answer: b
Explosion: The other name of this process is called ‘steam explosion’. Chips are steamed at 180-250 degree celcius.

7. What is the temperature range at which chips are steamed in the Masonite process?
a) 1500-1690 degree Fahrenheit
b) 35-80 degree Fahrenheit
c) 155-480 degree Fahrenheit
d) 335-480 degree Fahrenheit
Answer: d
Clarification: The other name of this process is called ‘steam explosion’. Chips are steamed at 180-250 degree celcius.

8. What is the range of yield in the Masonite process?
a) 50-60%
b) 40-30%
c) 80-90%
d) 10-20%
Answer: c
Clarification: In fiberboard the fibers are held together by resins such as phenol-formaldehyde. The yield is 80-90%.

9. Chips are steamed well above the glass transition temperature of lignin, for one to two minutes until final pressure is on the order of __ MPascal.
a) 14-20
b) 4-7
c) 19-25
d) 3-4
Answer: b
Clarification: Chips are steamed well above the glass transition temperature of lignin, for one to two minutes until final pressure is on the order of 4-7 MPascal.

10. A mild explosion pulping process is being used at one mill to process __ paper.
a) Recycled
b) Un-used
c) Over-used
d) Bloated
Answer: a
Clarification: A mild explosion pulping process is being used at one mill to process recycled paper.

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Pulp and Paper Multiple Choice Questions and Answers (MCQs) on “Pulp Characterization”.

1. Pulp characterization is very important to determine the effects pulping, bleaching, refining, etc. on the properties of the pulp and, therefore, on the final paper properties.
a) True
b) False
Answer: a
Clarification: Pulp characterization is very important to determine the effects pulping, bleaching, refining, etc. on the properties of the pulp and, therefore, on the final paper properties.

2. The moisture content of pulp is calculated by drying a weighed portion of pulp in an oven at ____________ to constant weight .
a) 105 ± 3°C
b) 85 ± 3°C
c) 35 ± 3°C
d) 15 ± 3°C
Answer: a
Clarification: The moisture content of pulp’s calculated by drying a weighed portion of pulp in an oven at to 105 ± 3°C (221 ± 5T) constant weight.

3. What is the handsheet former called?
a) Dutch sheet mold
b) British sheet mold
c) French sheet mold
d) Lebanese sheet mold
Answer: b
Clarification: Round handsheets 15.9 cm (6.25 inches) in diameter are made according to T.A.P.P.I Standard T 205 and tested by methods in T.A.P.P.I Standard T 220.

4. Which of the mechanical pulps have significant fiber curling?
a) TMP
b) RPM
c) PWG
d) CMTP
Answer: a
Clarification: T.M.P. These pulps are prepared according to T.A.P.P.I Standard T 262, circulating 2% consistency stock at 90-95 °Celcius, to fully develop their strength properties by removing the curl.

5. The ____________ is a measure of the average chain length (degree of polymerization, DP) of cellulose.
a) Pulp velocity
b) Pulp viscosity
c) Lignin velocity
d) Lignin viscosity
Answer: b
Clarification: It is determined after dissolving the pulp in a suitable solvent such as cupriethylenediamine solution.

6. Increase in viscosity result from chemical pulping and bleaching operations and to a certain extent are unavoidable.
a) True
b) False
Answer: b
Clarification: Decreases in viscosity result from chemical pulping and bleaching operations and to a certain extent are unavoidable.

7. ____________ Standard T 261 is a means of measuring the fines content of pulps with a single screen classifier, the so-called Britt jar test.
a) TAPI
b) TARF
c) THNJ
d) TAPPI
Answer: d
Clarification: TAPPI Standard T 261 is a means of measuring the fines content of pulps with a single screen classifier, the so-called Brittjar test.

8. What is the name of the device?

a) Kajaani optical fiber analyser
b) Tyler optical fiber analyser
c) Kurt optical fiber analyser
d) Virgo optical fiber analyser
Answer: a
Clarification: Kajaani optical fiber classifier with analysis of 19,060 fibers (60% hardwood, 40% softwood by weight). Averages are number, 0.55 nun; length, 1.16 mm; and, mass, 1.88 mm.

9. What is the name of the device?

a) Kent pulp fiber classifier
b) Clark pulp fiber classifier
c) Max pulp fiber classifier
d) Magneto pulp fiber classifier
Answer: b
Clarification: Fiber lengths can also be determined by fiber classification using a series of at least four screens of increasingly smaller openings (TAPPI Standard T 233); two common instruments are the Clark type or Bauer-McNett type.

10. Papers containing ____________ that reduce CUSO₄ might be utilized, provided the total reducing power of the additives is known and no more than about 75% of the total reducing power of the sheet.
a) ZnS and CaSO₄
b) ZnSO₄ and CaCO₃
c) CaCO₃ and MnO₂
d) ZnS and CO₂
Answer: a
Clarification: Papers containing ZnS, CaSO₄, melamine resins, and other materials that reduce CuSO₄ might be utilized to provide the total reducing power of the additives is known and no more than about 75% of the total reducing power of the sheet.

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Pulp and Paper test on “The Fourdrinier Wet End”.

1. The _________ is a paper machine with a fine mesh, woven wire cloth or plastic fabric on which the pulp slurry’s deposited.
a) Heatbox
b) Headbox
c) Aluminator
d) Fourdrinier
Answer: d
Clarification: The fourdrinier, a paper machine which forms the web. The front side or tending side’s the side from which the paper machine’s controlled, whereas the other side’s the backside.

2. Clothing Paper machine doesn’t consists of forming fabrics, press felts, and dryer felts.
a) True
b) False
Answer: b
Clarification: It consists of forming fabrics (wires), press felts, and dryer felts.

3. _________ is a continuous loop or belt of fine screen made from wire or plastic .The mesh size ranges from 40 – 100 mesh openings per inch.
a) Flocculation
b) Deflocculation
c) Alum
d) Forming fabric
Answer: d
Clarification: The wire, or now more precisely called the forming fabric. It’s a continuous loop or belt of fine screen made from wire or plastic.

4. _________ are high press. showers on the underside of the wire utilized to remove fillers and other material which could plug the wire.
a) Pressure heads
b) Wire showers
c) Forming fabric
d) Alum
Answer: b
Clarification: Generally, they move back and forth slowly to clean all parts of the wire and prevent wire wearing in 1 spot.

5. The breast roll is located under the _________ and serves to return the fabric back to the forming area to receive the stock once again.
a) Heatbox
b) Headbox
c) Pressure heads
d) Forming fabric
Answer: b
Clarification: It must be rigid enough to resist deflection. Shows the breast roll from a linerboard machine. During the era of pressure forming, it served as a H₂removal device acting like a table roll. Pressure forming is not utilized now, except in tissue forming.

6. The continuous mat of fibers which has already formed the final paper is called as the _________
a) Matte
b) Web
c) Corona
d) Oasis
Answer: b
Clarification: The continuous mat of fibers that’s in the process of forming or which has already formed the final paper’s called as the web.

7. Table rolls are freely revolving rolls under the _________ wire that support the weight of the wire and wet web.
a) Heatbox
b) Headbox
c) Aluminator
d) Fourdrinier
Answer: d
Clarification: Water is removed from the bottom of the web by a partial vacuum 45 kPascal below ambient pressure or 14 inches of mercury at machine speeds of 2000 ft/min over a distance of about 10 mm at the meniscus that forms at the nip where the roll leaves the wire.

8. The width of sheet sent to the press section’s calibrated by _________
a) Cutters
b) Slitters
c) Trim squirts
d) Razor squirts
Answer: c
Clarification: The narrow bands of stock left on the fabric are slacked off by edge squirts. On newer designs of fabric there may have to be 2 trim squirts in line upon each side to get a clean “cut”. Economics dictate that a min.should be wasted in trinuning, about 2-3 inch which return’s back to the paper machine.

9. Hansen in 1991 developed suction using water-filled drop legs barometric legs like those utilized in brown stock washers to provide siphoning action. These are known as _________
a) Solid boxes
b) Dry boxes
c) Lovac boxes
d) Wet boxes
Answer: c
Clarification: The pressure gradient’s proportional to the height of the H₂O column. 4 distinct types of covers are used, all of which are slotted. To cause drainage only, a series of flat blades 7 – 13 is common.

10. In the progression along the forming table the stock’s subjected to inc. A.P. to drain the sheet.
a) True
b) False
Answer: a
Clarification: Lovacs rarely operate above 50 inches W.G. The stock encounters the hivacs. The term flat box is not right, as curved covers are utilized regularly on 2 wire machines.

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Pulp and Paper Multiple Choice Questions on “Molecular Weight of Polymers”.

1. __________ consist of individual polymers with varying molecular weights. The properties of the polymers depend on the distribution of molecular weights.
a) Monodisperse
b) Polydispersity
c) Cellulose chain
d) Synthetic polymer
Answer: a
Clarification: Synthetic polymers consist of individual polymers with different molecular weights. The properties of the polymers depend not only on the average molecular weight but on the distribution of molecular weights as well.

2. Several methods utilized to characterize polymers give average molecular weights that depend on the molecular weight distribution as well as the number average molecular weight.
a) True
b) False
Answer: a
Clarification: Most of the methods are utilized to characterize polymers give average molecular weights that depend on the molecular weight distribution as well as the number average molecular weight.

3. A __________ depicted as Mn, Let Ni equal the number of the molecules or moles or other calculated of number of molecules with mass M, or a calculated of mass such as D.P.
a) Number average molecular weight
b) Number mean molecular weight
c) Number median molecular weight
d) Number mode molecular weight
Answer: a
Clarification: The 1st is a simple average where each molecule contributes equally to the average a number average molecular weight depicted as Mn. Let Ni equal the number of the molecular or moles or other measure of number of molecular with mass M, or a measure of mass such as D.P.

4. A number average molecular weight is obtained by methods that solely depend on the colligative properties of polymer solutions.
a) True
b) False
Answer: a
Clarification: A number average molecular weight is extracted by methods which solely depend on the colligative properties of polymer solutions.

5. One such method is vapour phase __________ that indirectly measures vapor pressures of polymer solutions.
a) Symmetry
b) Osometry
c) Isentropic
d) Adiabatic
Answer: b
Clarification: Such methods are limited to low molecular weight polymers several thousand grams per mole or less. This method has the drawback that it does not represent the behaviour of polymer mixtures very well. Vapor phase osmometry indirectly measures vapour pressures of polymer solutions.

6. The __________ is always higher than the number average molecular weight, except for the special case when they are equal if all of the polymers have the exact same molecular weight.
a) Weight average molecular weight
b) Weight average cation weight
c) Weight average anion weight
d) Weight average quinon weight
Answer: a
Clarification: The weight average molecular weight is always greater than the number average molecular weight, except for the special case when they are equal if all of the polymers have the exact same molecular weight example a monodisperse sample, the ratio is then greater than one.

7. What is the name of the hidden part?
a) Number average molecular weight
b) Weight average
c) Monodisperse
d) Polydispersity
Answer: a
Clarification: The number average molecular weight is the total weight of the sample divided by the number of molecules in the sample. It could be calculated by the above formula for the react.

8. What is the name of the hidden part?

_________= (ΣN_i x ΣM_i) / (ΣN_i)

a) Number average molecular weight
b) Weight average
c) Monodisperse
d) Polydispersity
Answer: a
Clarification: Then number average molecular weight is the total weight of the sample divided by the number of molecules in the sample. It could be calculated by the above formula for a particular react.

9. What is the name of the hidden part?

________= (ΣN_i x ΣDP_i) / (ΣN_i)

a) Number average molecular weight
b) Weight average
c) Monodisperse
d) Polydispersity
Answer: b
Clarification: A weight average molecular weight is determined by light scattering methods but is limited to relatively great molecular weights.

10. What is the name of the hidden part?

_________ = (ΣN_i x ΣDP²_i) / (ΣN_i x DP_i)

a) Number average molecular weight
b) Weight average
c) Monodisperse
d) Polydispersity
Answer: b
Clarification: A weight average molecular weight is calculated by light scattering methods but is limited to relatively great molecular weights.

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Pulp and Paper Multiple Choice Questions on “Papermaking Control Chemistry”.

1. _________ is usually anionic if it has any charge and may contribute to anionic trash.
a) Dispersant
b) Flocculation
c) De-flocculation
d) Pith
Answer: d
Clarification: Calcium ions form precipitates with wood pitch. It could be natural or manufactured or derived from petroleum, coal tar, and plants.

2. Wood pitch is concentrated in _________ cells and may be squeezed out in refining, paper pressing, and other operations.
a) Collenchyma
b) Parenchyma
c) Girth
d) Phloem
Answer: b
Clarification: The cellular tissue, typically soft and succulent, found chiefly in the softer parts of leaves, pulp of fruits, bark and pith of stems, etc. Pitch could contribute to foam formation when the pitch molecules attach to air bubbles.

3. Cationic retention aids such as _________ may help bind wood and other pitch materials to the stock to prevent their concentration in the system.
a) Silicon
b) Alum
c) Copper
d) Aluminium
Answer: b
Clarification: The specific compound is the hydrated KAl(SO4)2. Pitch may be absorbed on talc if the pitch is dispersed.

4. _________ are utilised to keep the pitch from forming aggregates, but may contribute to poor retention and foaming.
a) Dispersant
b) Flocculation
c) De-flocculation
d) Pith
Answer: a
Clarification: The dispersing agent or a plasticizer added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling. They consist normally of 1 or more surfactants, but might also be gases.

5. In addition to surfactants, finely divided solids can contribute to foam problems.
a) True
b) False
Answer: b
Clarification: These solids include fillers, alumina, fines, and other colloids that can surround air bubbles to decrease the surface tension.

6. _________ unlike other dyes, are soluble in moderately polar to non-polar materials like the lower alcohols and oil.
a) Acidic dye
b) Basic dye
c) Cationic dye
d) Anionic dye
Answer: b
Clarification: They have a tendency to work unevenly and may give a surface that appears somewhat like granite. This dye is generally synthetic, that act as bases, and which are actually aniline dyes.

7. Pulps with low cellulose viscosity refine faster, so the refiner operator should be aware of changes in the pulp viscosity.
a) True
b) False
Answer: a
Clarification: The level of refining can be followed with Simons in 1950 stain of fibers observed through a microscope. Even without staining, refining can be followed qualitatively with microscopic observation.

8. The reason the _________ work by different mechanisms and affect components of drainage differently because of improved _________ at the flat boxes which doesn’t mean the consistency at the couch will be improved.
a) Drainage aids
b) Online sensors
c) Offline sensors
d) Simons sensors
Answer: a
Clarification: H₂O is the carrier of all major paper components and typical furnish consistencies of 0.3−1.5% are required to achieve the paper properties desired, it becomes obvious that the removal of large quantities of H₂O is
the key to better productivity and costs.

9. _________ usually requires manual sampling of process streams which is critical to obtain a representative sample.
a) Drainage aids
b) Online sensors
c) Offline sensors
d) Simons sensors
Answer: c
Clarification: This isn’t easy in the case of paper machine white H₂O; in this case sampling of more than one region may be required, and each sample must be representative of the area from which it is collected.

10. _________ are superior to off-line measurements that take operator time and data is available immediately to control the process.
a) Drainage aids
b) Online sensors
c) Offline sensors
d) Simons sensors
Answer: b
Clarification: Measurements of pH, conductivity, temperature, flow rates, zeta potential, certain ions, and flow rates are well established and do not require operator time to collect.

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Pulp and Paper Multiple Choice Questions on “Flow of Liquids”.

1. In order to simplify the mathematical development, flow is often considered in rectangular cross section pipe.
a) True
b) False
Answer: b
Clarification: The flow of liquids in pipes can be difficult to describe mathematically. To simplify the mathematical development, flow is usually considered in circular cross section pipe.

2. The ___________ is an crucial parameter utilized to predict the flow pattern in a pipe.
a) Plank’s number
b) Reynold’s number
c) Kraft’s number
d) Sherwood number
Answer: b
Clarification: It is defined as the ratio of inertial forces to viscous forces and consequently quantifies the relative crucial of these 2 types of forces for given flow conditions.

3. If the Reynolds number is below 2000, the flow tends to be __________
a) Turbulent
b) Laminar
c) Transitional
d) Can’t be predicted
Answer: b
Clarification: It is a flow regime characterized by high momentum diffusion and less momentum convection. Whenever a fluid is flowing through a closed channel such as a pipe or between 2 flat plates, either of 2 types of flow may occur depending on the velocity and viscosity of the fluid.

4. If the Reynolds number is above 2000, the flow tends to be ___________
a) Turbulent
b) Laminar
c) Transitional
d) Can’t be predicted
Answer: b
Clarification: Turbulent flow is a flow regime characterized by chaotic changes in pressure and flow velocity. In unsteady vortices appear on many scales and interact with each other. Drag due to boundary layer skin friction inc.

5. The addition of a small amount of ___________ to H₂O may actually reduce friction compared to H₂O alone.
a) Pulp
b) Lignin
c) Fiber
d) Polymer
Answer: c
Clarification: The addition should be done on the order of 0.3% consistency although it can be higher at higher flow velocities, so it could actually reduce friction compared to H₂O alone.

6. What is the name of the equation?

Q = (πΔPr⁴) / (8µL)

a) Darcey equation
b) Poiseuille law
c) Reynolds equation
d) Sherwood law
Answer: b
Clarification: The Hagen–Poiseuille equation also called as the Hagen–Poiseuille law, is a physical law that gives the pressure drop in an incompressible and Newtonian fluid which is flowing through a long cylindrical pipe in laminar flow of constant cross section.

7. What is the name of the equation?

h = (fvL) / (2Dg)

a) Darcey equation
b) Poiseuille law
c) Reynolds equation
d) Sherwood law
Answer: a
Clarification: It’s a constitutive equation that describes the flow of a fluid through a porous medium. It’s based on the results of experiments on the flow of H₂O through beds of sand, forming the basis of hydrogeology, a branch of earth sciences.

8. What does u_b stands for?

Re = (Du_bρ) / µ

a) Initial velocity
b) Final velocity
c) Bulk velocity
d) Blocking velocity
Answer: c
Clarification: If the flow regime is laminar the problem still exists of trying to represent the “average” velocity at any given cross-section since an average value is utilized in the fluid flow equations. For fluid flow in a pipe or duct, the average flow velocity, given by V = ṁ/ρA.

9. For Reynolds number below 2000, f has been empirically shown to be equal to 64/Re.
a) True
b) False
Answer: a
Clarification: In case of Laminar flow, it’s a consequence of Poiseuille’s law from an exact classical solution for the fluid flow that where Re is Reynold’s number and where µ is the velocity of the fluid and is known as kinematic viscosity.
fD =64/Re, Re=V.D/v.

10. ___________ is the sudden change in pressure cautilized by a column of H₂O that suddenly changes velocity (as when a valve is closed).
a) H₂O hammer
b) Globe hammer
c) Needle hammer
d) Air check hammer
Answer: a
Clarification: It’s a pressure surge or wave cautilized when a fluid generally a liquid but sometimes also a gas in motion is forced to stop or change direction suddenly (momentum change). It’s also known as hydraulic shock.

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