Pulp and Paper Multiple Choice Questions on “The Dryer Section”.
1. _________are steam filled drums designed to heat the web by direct contact and remove water by evaporation.
a) Winder
b) Dryer
c) Converters
d) Reel
Answer: b
Clarification:Dryers are hollow, revolving, steam filled drums about 2 m or 6 ft in diameter designed to heat the web by direct contact and remove water by evaporation.
2. The _________ is designed to keep hot, dry air over the free paper surface, and the pockets b/w dryer drums where H2O quickly evaporates.
a) Reel
b) Winder
c) Dryer
d) Ventilation system
Answer: d
Clarification: The ventilation system’s designed to keep hot, dry air over the free paper surface. Pocket ventilation systems blow hot, dry air into the pockets through air ducts and nozzles at high velocity Hot, dry air may also be utilized to dry the dryer felts to improve web drying.
3. _________ keeps the paper web against the drums to enhance heat transfer b/w the drum and web and absorb a portion of the H2O evaporated from the web.
a) Reels
b) Calendar
c) Dryer hood
d) Dryer felts
Answer: d
Clarification:They help keep the sheet flat to min. cockle formation on the web and enhance drying. Even tension on the felt across the machine is crucial Fundamenatally, the felt’s non-absorbent, strong, flexible, and as always inexpensive.
4. The first step in controlling the heating of _________ is to remove the steam condensate from the drum.
a) Pocket ventilation
b) Reverse press
c) Press felt
d) Dryer drums
Answer: d
Clarification: The condensate tends to form pools or puddles at low machine speeds and rims at speeds about 1200 ft/min.
5. The _________ is an enclosure around the dryer section and is used to enhance drying efficiency.
a) Dryer hood
b) Reel
c) Calendar
d) Ventilation system
Answer: a
Clarification: It’s used to enhance drying efficiency by removing the moist air near the surface of the web. If this air isn’t completely removed, it quickly becomes saturated with H2O, preventing further H2O removal from the web.
6. The _________ is a large dryer drum for drying tissue papers that aren’t strong enough to go through no. of felt transfers.
a) Pocket ventilation
b) Dryer hood
c) Yankee dryer
d) Impulse drying
Answer: c
Clarification: It’s a large dryer drum 3.5- 4.5 m or 12-15 ft. in diameter for drying tissue papers that are cannot endure numerous felt transfers. It’s normally the only dryer used to dry tissue.
7. The use of a long press nip with one roll at 175-400°Celcius to remove water from the web’s called as _________
a) Yankee drying
b) Reel
c) Dryer hood
d) Impulse drying
Answer: d
Clarification: The objective is to vaporize some of the H2O quickly so that the generated steam front forces much of the rest of the H2O out as a liquid. This eliminates the energy required to vaporize much of the H2O and reduces the dryer section size.
8. The _________ is located b/w dryer sections and consists of a pair of squeeze rolls mounted horizontally, vertically, or at a 45 degrees angle.
a) Ventilation point
b) Size press
c) Dryer hood
d) Calendar stack
Answer: b
Clarification: At a 45° angle, it’s used to apply surface size usually a starch solution to papers.
9. Surface size uses _________ materials, commonly starch, but sometimes starch reacted with ethylene oxide are applied as a solution to the surface of the web at the size press, followed by drying.
a) Polymeric
b) Radioisotopic
c) Metallic
d) Non metallic
Answer: a
Clarification: Surface size uses polymeric materials, commonly starch, but sometimes starch reacted with ethylene oxide hydroxyethyl starch with a relatively low degrees of substitution, carboxymethyl cellulose, polyvinyl alcohol, methyl cellulose, alginates, or wax emulsions utilizing alum that are applicable as a sol. to the surface of the web.
10. Sizing efficacy may by measured by the _________
a) Kennedy porosity
b) Gurley porosity
c) Sizing porosity
d) John porosity
Answer: b
Clarification: Typically about 30-50 percent wet pick-up is utilized or 300-500 kg/t in surface sizing. Papers without internal size may get to up higher levels. Sizing efficacy may by measured by the Gurley porosity.
>