Cottonseed pretreatment: delint 90-95% + dehull 35-45% + cook 110-130°C
Cottonseed pretreatment hard data and module sequence: 1) Cleaning (vibrating screen + magnetic separator + destoner) to impurities <0.1%. 2) Delinting: acid (sulfuric 8-12% bath, 90-95% lint removal, fast) or saw linter (mechanical, 70-85% removal, no chemical). Linter 5-15% of seed → cellulose/cotton-pad market. 3) Dehulling (sheller + air aspirator): hull 35-45% of seed, kernel-rich feed for higher yield (28-35% on kernel vs 14-18% on whole seed). 4) Cooking 110-130°C × 30-60 min → moisture 8-12% → 6-8%, gossypol gland rupture. 5) Grinding/stirring 1-3 mm uniform feed to barrel.
Delinting options
Acid delinter (sulfuric 8-12% bath): 90-95% lint removal, faster, but acid handling + waste disposal capex. Saw linter (mechanical rotating saws): 70-85% removal, no chemical, slower throughput.
Hull management
Sheller + air aspirator: hull 35-45% of seed → kernel-rich feed. Higher yield 28-35% on kernel vs 14-18% on whole seed. Hulls go to ruminant feed, boiler fuel, or particle board feedstock.
Cooking spec
Steam-jacketed cooker 110-130°C × 30-60 min, moisture in 8-12% → out 6-8%, gossypol pigment glands ruptured (improves later refining gossypol reduction). Grinder 1-3 mm uniform particle.
Module specifications
Five-step pretreatment with capacity ranges
Delint: acid or saw
Acid delinter (H₂SO₄ 8-12% bath, 90-95% lint removal, capacity 2-10 t/h). Saw linter (mechanical, 70-85% removal, capacity 1-5 t/h, no chemical waste). Choose by capex + waste-disposal availability.
Clean: <0.1% impurities
Vibrating screen (40-100 mesh) + magnetic separator + destoner (gravity table). Capacity matches line throughput 1-10 t/h. Output: clean delinted seed, impurities <0.1%, stones <0.05%.
Dehull: 35-45% removal
Sheller (drum or roll) + air aspirator separates hull (35-45% of seed) from kernel. Kernel-rich feed → 28-35% yield (vs 14-18% on whole seed). Hulls collected for ruminant feed/fuel/board.
Cook + grind
Steam-jacketed cooker 110-130°C × 30-60 min (moisture 8-12% → 6-8%, gossypol gland rupture) + roll/hammer mill 1-3 mm + stirring tank for uniform feed to press barrel.
Common errors
Where cottonseed pretreatment fails
- Skipping delinting (>15% lint remaining): linters clog cooker steam jackets, foul press barrel partitions, contaminate oil with cellulose fibers.
- Skipping dehulling (whole-seed feed): yield only 14-18% (vs 28-35% on kernel), cake protein 23-28% (vs 41-44% decorticated), darker oil.
- Cooking below 110°C or above 130°C: gossypol glands not fully ruptured (refining cannot reduce free gossypol below 0.045%), or protein scorching darkens oil.
- Moisture out of cooker >9% (cake bypass channels) or <5% (brittle cake) → residual cake oil >10%, yield drops 3-5 pt.
- Treating cottonseed line as 'cooked + pressed' without naming delinter type, sheller, cook temp/time, and grinder spec.
Questions to confirm next
Acid delinter or saw linter for cottonseed?
Why dehull cottonseed before pressing?
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