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Based on: Industry Standards and Best Practices

Languages: English

Sample Transcript

Refining action is caused by passing blown digester material, the cooked wood chips, and black liquor between two large metal disks with ridged surfaces. Typically, one of the discs rotates and one is stationary causing a shearing action on the blown material as it passes through the gap between the disks. The amount of energy that goes into the pulp is controlled by the size of the gap the material passes through. Decreasing the gap increases the energy applied, and the amount of work done on the material. By applying different amounts of energy to the material, the effects on the pulp can be controlled. The gap is controlled by positioning devices that move the rotor towards or away from the stater or by a motorized screw drive.

Blow Line Refining Operation

Training Time: 26 minutes

Blow line refining is an important part of the industrial process that converts wood chips into paper and other useful cellulose based products. Blow line refiners typically operate downstream of a continuous digester and act to break apart cooked wood chips as they are discharged from the digester. This module will describe the purpose, components, and operation of blow line refiners.

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In a two disk refiner, pulp enters through on opening in the middle of the disks and then flows outward through the space between them.

The amount of energy applied to the fibers in the pulp is controlled by changing the gap between the disks.

Refiner disks have patterned steel plates attached to them. The plates can be removed due to wear, to  install a different pattern, which will change how the fibers are refined.

Refiner disks have patterned steel plates attached to them. The plates can be removed due to wear, to install a different pattern, which will change how the fibers are refined.

Learning Objectives

  • Describe the purpose of blow line refining
  • Describe blow line refining process theory
  • Identify and describe the components of a blow line refiner
  • Describe blow line refiner operation
  • Explain the effects of refining on pulp properties
  • Describe the safety hazards associated with blow line refining
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Blow Line Refining Operation FAQs

What is meant by ""refining"" of pulp?
The primary effect on pulp of blowline refiners is to break apart cooked chips and separate them into fibers.

What is one advantage provided by a blowline refiner?
Blowline refining reduces the load on knotting and screening systems by reducing the level of rejects.

What is the physical form of a refiner?
A typical blowline refiner consists of two large metal disks with ridged inner surfaces. One disk is rotated by a motor and one is stationary.

What in the primary operating parameter which controls of the amount of energy applied to pulp going through a refiner?
The amount of energy imparted to the pulp is related to the space between the disks, so gap control is important.

What is the effect of applying excessive energy to the pulp?
Excessive shear forces applied to the pulp will result in crushing and/or cutting of the actual fibers.

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