Acid Delinting

(C) Process Description Of Continental Eagle’s
New Dilute Sulfuric Acid Delinting System Using Combination Dry- Buff Machine

The fuzzy seed are discharged from a metering feed bin by a speed-controlled auger. The seed fall into the reactor which is an auger with paddle type flighting. A carefully regulated flow of dilute acid is added to the seed in this reactor, and the paddle flighting thoroughly blends the seed with the acid solution, and conveys the mixture to an elevator. The elevator lifts the acidified seed and discharges them into the delinting machine.

The dilute acid solution consists of sulfuric acid added to water to give a concentration as deemed appropriate by the operator, usually in the range of 8 to 12% acid. A surfactant or wetting agent is added to enhance the penetration of the solution into the cotton fibers.
The proportioning of these materials can be controlled either electronically or manually. An electric motor driven pump provides continuous agitation and assures a constant supply of solution to the reactor.

Inside the delinting machine the seed are tumbled as warm air is blown through them evaporating the water. As the water evaporates the acid becomes concentrated enough to hydrolyze the linters. The hydrolyzed linters are scrubbed, or buffed, off the seed by the tumbling action rubbing the seed against each other and the sides of the perforated drum. The air passing through this perforated drum conveys the linters to approved dust control devices.

The delinted seed are then discharged from the delinting machine and pass through an air-screen cleaner, gravity separator, and treater. In the treater some calcium carbonate can be added to the fungicide in order to neutralize any acid that might remain on the seed coat.

The hydrolyzed linters can be discharged into an enclosed screw conveyor where anhydrous ammonia or .other alkaline material can be introduced if neutralization of the linters is desired.

For general guidelines, an approximate materials consumption per one (1) metric ton of fuzzy seed input is 150 to 165 liters of water, 9 to 11 liters (16 to 20 kg) of sulfuric acid, 66° Baume, and I to 1.5 liters of surfactant. Heat is supplied by a one million BTU rated capacity burner, and the air flow is provided by a 40 horsepower centrifugal blower. Temperature inside the drum is precisely regulated to prevent heat damage to the seed. The drum is rotated by a 10 horsepower motor. The hydraulic pump operating the cylinders used for raising and lowering the discharge end of the drum is powered by a 0.75 horsepower motor.