Industrial Kraft Paper Manufacturing

Waste paper is sorted manually to pick out plastic, wax-coated paper, bitumen etc. and fed into the vertical pulper through conveyor. The waste paper bales or pulp bales are fed in via a conveyor to the pulper and repulped by adding process water Water is added for slushing and the whole content is agitated to make pulp from the waste paper. The pulper rotator (agitator) ensures the disintegration of waste paper fibres. Some systems process only one batch at a time, while others operate continuously, such as repulping drums used for waste paper. This pulp is then sent to the sand trap for removing the sand. . The pulper rotator (agitator) ensures the disintegration of waste paper fibres. Some systems process only one batch at a time, while others operate continuously,

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The pulp is taken to the decker drum for increasing the consistency of the pulp and subsequently stored in the Chest. Alum, rosin and other additives are added at this stage and then it goes to the paper machine. The pulp from this chest is pumped through a single disc refiner and stored in the machine chest. Now this pulp goes to a three stage centri-cleaner to remove the knots and other impurities.
Efficient fibre separation in the pressurised screen. Any impurities bigger than the fibres must be separated out. For this purpose, the fibre suspension is pumped through a pressurised screen at a pressure of approx. 2 bar (29 psig) at approx. 50°C (122°F). The material flows in tangentially along the surface of rotating screen cylinders with holes or slots. The screening machines have an inlet, an outlet for good material (accept) and an overflow for sorted out material (reject). The separating efficiency is defined by the hydraulic pressure of the screen, the dimensions of the holes or slots and the quantity of reject.




The paper machine has 3 principal stages: Headbox, the heart of the paper machine. After dilution and screening in the approach flow the suspension consisting of fibres, additives and water must be fed uniformly in web width to the screen part of the paper machine. For this it is pumped to the headbox via a tapered manifold flowspreader as well as several pipe manifolds. Pressure and speed must be constant in these areas.

i) The gravitational and vacuum de-watering stage i.e. Wire pit - here pulp is fed at a consistency of around 0.7% and when the paper goes out of this stage the consistency becomes around 20%.
ii) The mechanical de-watering stage. i.e. Press Section - Here the paper with 20%consistency (80% moisture) is squeezed through a set of press rolls (having 2 rolls in each set) to get 35% consistency paper (65% moisture).
iii) The final moisture content of the paper rolled on to the pop-reel is around 5- 6%. The paper from the pop-reel goes to the rewinder for making reels in required sizes and then it goes to despatch Section.