Proses of Wood Chip refining is , Kecuali:

• separate fibers  from each other in the wood material.

• The fibers are separated and worked by  the compressive and shearing stress  forces in the refiner

• Fiber is compacted

• Fiber separation and Further refining

The refiner segments are an  important factor in refiner  operations and the quality of the  pulp produced.

• True

• False

In most refiners, the segments are attached to segment holders, When replacing the segments,  they are replaced not including the segment holders.

• True

• False

The strongest remedy for improving the pulp quality or raising the mill capacity is the refiner segments. They affect, kecuali:

• Capacity and pulp quality

• Refining energy consumption

• Refiner runnability

• Refiner error

The first stage of refining wood material is heated and its structure is loosened by compressive forces. Steam is generated, The wood material disintegrates into fiber bundles,  separate fibers, and fiber constituents due to the shearing forces (frictional forces) between the refiner segments.

• True

• False

Refining affects fibers in many ways. Kecuali:

• –Removal of primary fiber wall which prohibits fiber swelling because of its rigidity.

• –Internal and external fibrillation detach and break the fibrils so that the fiber surface becomes hairy.

• –Delamination and swelling of fibers.

  Shortening of fibers.

  Creation of fines.

• Fiber un fibrillated

Refining intensity impact, kecuali

• Gap between refining plates

• Fibers are collapsed and their bonding surface area is increased.

• Depending on the intensity of refining, fibers can be more fibrillated or shortened.

• Correct refining intensity gives fibrillated fibers while too severe refining intensity produces more cut fibers.

Process variables affecting chip refining's, kecuali:

• Refining consistency

• Inlet pressure

  Housing pressure

• Inlet temperature

  Chip preconditioning

• Wood species

Raw material Variables affecting chip refining, kecuali:

• Wood species

  –Variations between each forest will  exist

• Age of wood

  –Should not be more than six weeks old.

• Refiner segment pattern

• Chip size and quality

  –Determined by the condition of the chipper knives and the wood.

Definition of Fiber sheet Brightness, Brightness is a function of a surface's ability to scatter(s) and absorb (k) light!

• Benar

• Salah