Engineering Questions with Answers - Multiple Choice Questions
Chemical Process Technology MCQ’s – Natural Products – Pulp
1 - Question
Pulp suitable for producing high strength paper is obtained by _________________
a) Chemical pulping process
b) Ground wood process
c) Semi-chemical process
d) Fiber suspension
Explanation: Fiber suspension preparation is first step of making paper whereas other processes produce pulp. Pulp obtained from chemical process is very much suitable for paper having high strength though its yield is less.
2 - Question
Waste product obtained in the conversion of pulpwood to paper pulp by Kraft process is __________
a) Yellow liquor
b) Green liquor
c) White liquor
d) Black liquor
Explanation: Black liquor also known as wood digestion liquor is the waste product produced. White liquor is produced in the chemical recovery of sulfate pulp digestion liquor which is fed to the digestors.
3 - Question
Vacuum flash drying can be used for shipping pulp to use in paper making.
Explanation: Several ways of dewatering pulp which is useful in its shipping are hydraulically pressing pulp, vacuum flash drying, and extrusion in form of noodles or dried to 90% solids.
4 - Question
Chemical reagents used in digestors of Kraft process are ____________
a) Mg(HSO3)2 + SO2
b) Na2 CO3, Na2SO3, NaHCO3
c) NaHSO3, Na2SO3
d) NaOH, Na2S, Na2CO3 In aqueous solution
Explanation: 60%NaOH, 25% Na2 S, 15% Na2CO3 in 10-15%aqueous solution is the chemical reagent used in digestors of sulfate pulp process Mg(HSO3)2 + SO2, Na2CO3 + Na2S + NaHCO3, NaHSO3 + Na2 SO3 are the chemical reagents used in different types of sulfite processes.
5 - Question
Stabilizer added to maintain the peroxide (bleaching agent) concentration is ___________
c) Sodium silicate
d) Phosphoric acid
Explanation: Chlorine is not a stabilizer and generally sodium silicate is used as stabilizer for maintaining the peroxide concentration. These days it is replaced by an organic dye to prevent scale formation on internal surfaces.
6 - Question
Which of the following takes less time for digestion in Kraft process?
b) Paper pulp
c) Wood base material
d) Lignin free chemical cellulose pulp
Explanation: It might take 5-6 minutes for Bagasse, 2-5 hours for wood base material, longer time for lignin free chemical cellulose pulp, and a short time for paper pulp.
7 - Question
Which material is used for construction in Kraft process?
a) Mild steel
d) Acid proof brick
Explanation: Bronze, lead, and acid proof brick are materials of construction in sulfite process whereas mild steel is used in Kraft process as well as neutral sulfite process.
8 - Question
Brown color pulp is produced in sulfite pulping process.
Explanation: The statement is false as brown color pulp is produced in sulfate pulping process whereas sulfite process produces dull white color pulp which can be easily bleached.