The GATE Grind

GATE 2026 CH – Question 18

Chemical Technology · Natural products industries: pulp and paper, sugar and ethanol · 1 mark · Multiple choice

In a traditional continuous Kraft (Sulfate) pulping process, consider the following major steps: Bleaching (BL), Chipping (CH), Debarking (DE), Digestion (DI), and Pulp Washing (WA). Which one of the following is the CORRECT sequence of steps for this process?

  1. DE → BL → WA → DI → CH
  2. DE → CH → DI → WA → BL
  3. DE → CH → WA → DI → BL
  4. DE → BL → WA → CH → DI

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Show answer and explanation

Correct answer: (B) DE → CH → DI → WA → BL

Explanation

Logs are first debarked, then chipped, and the chips are cooked in the digester with white liquor. The cooked pulp is then washed to remove the black liquor and finally bleached. So the order is DE, CH, DI, WA, BL.