An integrated pulp and paper mill produces two paper grades (SC paper, LWC paper) and pulp at the mill site. Chemical pulp is made of pine chips and TMP-mill uses spruce chips as raw material. Round wood (pine) is transported to the mill to produce pine chips. Spruce chips are obtained from a sawmill near to the pulp and paper mill. Table 1 shows dailydemands of chemical and mechanical pulp.

Table 1. Daily demands of pine and spruce chips

Pulp Daily demand	tds/d
Pine chips	2214
Spruce chips	939

SC Super Calendered

LWC Light Weight Coated

C) Wood handling

Initial data:

Density of round wood

Pine 400 kg/k-m3 (*

Densities of chips

Pine 150 kg/i-m3

Spruce 140 kg/i-m3

Losses in screening

Pine chips 1.5 %

Spruce chips 0.5 %

Losses in debarking

Pine 12 %

*) kg/k-m3 = Density of dry matter before chipping,

i-m3 = Bulk density of dry solids.

The unit used in wood chipping is usually i-m3 (bulk volume = total volume taken

by chips and air). Therefore both mass and volume values are calculated in this part.

Calculate total demand of chips (pine + spruce) per day (i-m3/d).

Calculate total demand of non-screened chips (pine + spruce) by taking into account

losses in screening (i-m3/d).

Calculate how much waste wood is produced in screening in unit tds/d.

Calculate the average feeding rate of round pine wood into the debarking plant in

units tds/d and k-m3/d.

Calculate how much bark is formed in debarking in unit tds/d.