Question

After steaming at ______ pressure, the chips are brought to the digester pressure of ______ kPa.

(a) Low, 500

(b) High, 500

(c) High, 1000

(d) Low, 1000

I got this question in quiz.

I want to ask this question from Pulping, Digestion and Bleaching topic in division Paper and Paper Based Packaging Materials of Food Packaging Technology

Answer 1

Correct choice is (d) Low, 1000

For explanation: After steaming at low pressure, the chips are brought to the digester pressure of 1000 kPa. At LP, turpentine and gases are vented to the condenser. Then they are picked up in a stream of pulping solution and their temperature is raised to 170°C over 1.5 h. After holding at this temperature for a further 1.5 h, the digestion process is essentially complete.