PSE 476 1st Midterm January 17, 2007
Study Guide
Lectures 1-7 including Lecture 7 which is very important
Here is the study guide for the first exam. For those of you who haven’t taken a class from me I will typically ask
questions based on what is asked in this document. For this class, I will also look back at the questions from the
homework so it is important that you also look at these.
Introduction and Raw Material (Lecture 1)
1) I hope you learned a little bit about the history of papermaking in the first part of this lecture. Here are a couple
of questions regarding what I hoped you learned in this section.
a) Before paper was made from wood, what was it made from?
b) When were the first chemical pulping processes developed?
2) There are large differences in raw material use for pulp production in the United States based on geographic
location. I expect that you would know the following:
a) Are hardwoods or softwoods most used in the West? How about roundwood versus residual?
b) Are hardwoods or softwoods most used in the Southeast and South Central? How about roundwood versus
residual?
c) Are hardwoods or softwoods most used in the Northeast and North Central? How about roundwood versus
residual?
d) Why are there these differences in use patterns?
3) When material (wood/chips/whatever) comes into a mill there are a number of things which happen such as
debarking, chipping, washing, screening, testing etc. Why are these important?
4) Physical Measurements
a) Moisture content: Do you know the equations for moisture content green and oven dry? Which one is used
in the pulp and paper business
b) Density: Why is density important?
c) Why is chip size important?
d) What problems do debris cause?
5) Wood degradation: Why is this process a problem for pulp manufacture?
a) There are a variety of variables that affect the decay processes that go on in a chip pile. Why are the
following
i) Time in the pile
ii) Moisture
iii) Temperature
iv) Shape of the pile
Mechanical Pulping: (Lecture 2)
1) What is different between the raw materials used for stone groundwood and for refiner pulps?
a) What is important about the raw materials used in both processes in terms of age, species, cleanliness, etc?
2) Can you list in general terms the properties of mechanical pulps?
3) Can you describe the operation of a stone groundwood operation?
a) Why are there burrs on the stone?
b) How often are these burrs “sharpened”?
c) Why is water used in this process?
4) Can you explain the mechanism of the removal of fibers?
a) What effect does heat or chemicals have on this process?
b) What portion of the cell wall does separation occur?
c) What is the effect of getting the fibers too hot? Where does separation occur under these conditions? What
effect does this have on the resulting fibers?
5) Can you name the different type of refiner processes?
6) Can you draw a basic flowsheet for a refiner plant?
a) Why are chips washed before refinning?
b) Why is there more than one refiner in series in the process flow sheet?
