Dear Readers,
The presentation may be helpful for those who wants to know the basic concept of paper making process.
Please post your valuable comments improve the quality of presentation.
Regards,
Nirjhar.
2. Let us have an overall concept of paper making process with Nirjhar Chakravorti
3. Nirjhar Chakravorti, a Mechanical Engineer by profession, has completed engineering in the year 2000, from Jalpaiguri Government Engineering College, India. As an engineering professional Nirjhar has worked at different industries. Nirjhar’s interest is to know different technology and process engineering. During study about paper technology, Nirjhar has prepared this presentation, which can be helpful for those who wants to know the complete cycle of paper making process.
14. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical
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16. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer
17. Fiberizer The fiberizer is used for mixing dilution water into the suspension and for removing coarse contaminants. The pressure produced by the fiberizer rotor conveys the contaminants and part of stock suspension to downstream screening unit.
18. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept
19. Dump Tower Dump Tower is basically a storage tank. In Dump Tower, pulp gets sufficient retention time for chemical reaction, along with the chemicals added. From Pulper to Dump Tower, the production is Batch type.
20. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept High Density Cleaner
21. High Density Cleaner The High Density Cleaner cleans stock separation of sorted and unsorted waste paper. Relatively coarser contaminants such as small bolts, stones, wires and knots are separated. Cleaner protects machinery downstream against damage and rapid wear.
22. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept High Density Cleaner Hole Screen
23. Hole Screen Pulp is passed through multi-stage screen of Ø 1.2 mm holes. New developed machines, with special rotor geometry and Ø1 mm hole screen, can clean fibrous stock suspensions at consistencies up to 3.5%. In Hole Screening, contaminants removed at the beginning stages of stock preparation.
24. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept High Density Cleaner Hole Screen Stand tube Floatation Primary Cell
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26. Floatation Cell Floatation Machine comprises of cells in series forming a horizontal tube with elliptical cross section. A weir extending over the entire aggregate separates the suspension chamber from the foam collection channel. Suspension is removed uniformly from the bottom of each cell and pumped via aeration element to the next cell. Floatation Cell Continues….
27. Floatation Cell Function of aeration element is based on step diffuser design. Acceleration in the aeration tube generates a vacuum, which sucks the necessary process air, which forms bubbles in the stock. Bubbles remove particles from the stock suspension. Floatation Cell Continues….
28. Floatation Cell Dirt laden bubbles rise to the top of the cell, forming a foam layer. The foam layer carried over the wire into the foam collecting channel. The cleaner stock suspension remain in the cell and pumped to the next level.
29. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept High Density Cleaner Hole Screen Stand tube Floatation Primary Cell Venting Cyclone Foam Tank Floatation Secondary Cell Reject from foam chamber
30. Combined Floatation System Two stage floatation system is an important feature of modern de-inking plant. The primary floatation stage ensures high stock purity, while the secondary stage optimises floatation yield without sacrifice of brightness and cleanliness. Floatation foam from the primary stage is further deaerated in a cyclone before pumping to the secondary stage. Floatation Cell Continues….
31. Combined Floatation System In Secondary Cell, usable fibers are recovered from the foam, and the rejects from the Primary Stage are selectively removed from the system. The accept from the Secondary Stage is returned to the Primary Stage inlet.
32. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept High Density Cleaner Hole Screen Stand tube Floatation Primary Cell Venting Cyclone Foam Tank Floatation Secondary Cell Accept Reject CL1 CL2 CL3 CL4 Reject Accept Reject Accept Reject Accept stands for Heavy & Light Weight Cleaner CL
33. Heavy & Light Weight Cleaner After Floatation, light and heavy weight contaminants are cleaned in multi-stage cleaner. Multi-stage cleaner operates in the concept of cyclone cleaner.
34. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept High Density Cleaner Hole Screen Stand tube Floatation Primary Cell Venting Cyclone Foam Tank Floatation Secondary Cell Accept Reject CL1 CL2 CL3 CL4 Reject Accept Reject Accept Reject Accept Slot Screen Accept
35. Slot Screen After Cleaning, stock passes through the multi-stage Slot Screen Arrangement. Cleaned stock is pumped to the vertical screen. Accept from first stage Slot Screen pumped to the Disc Filter. Slot Screen Continues….
36. Slot Screen Reject from the first stage Slot Screen pumped to the second stage Slot Screen, via storage tank. From second stage Slot Screen, accept pumped to Disc Filter, and reject pumped to third stage Slot Screen via another storage tank. Slot Screen Continues….
37. Slot Screen From third stage Slot Screen, the accept goes to the tank placed in between first and second stage Slot Screen and reject goes to the sludge tank.
38. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept High Density Cleaner Hole Screen Stand tube Floatation Primary Cell Venting Cyclone Foam Tank Floatation Secondary Cell Accept Reject CL1 CL2 CL3 CL4 Reject Accept Reject Accept Reject Accept Slot Screen Accept Disc Filter
39. Disc Filter After Slot Screen, pulp is dewatered in the Disc Filter. The recovered water is re-used in various locations. For pulp dewatering, feed consistencies as low as 0.6% are acceptable. Discharge consistencies of 10-15% can be achieved. Disc Filter Continues….
40. Disc Filter The filter consists of low volume discs mounted on a horizontal shaft with conical flow channel. The filtrate valve at the outlet end of the shaft has a wear plate and bridges for separating the various filtrate zones. The filtrate valve is connected to a barometric drop-leg that generates the required vacuum. Disc Filter Continues….
41. Disc Filter The dewatered pulp is removed from the discs by jets of water and the filter cloth is continuously washed with an oscillating shower. The shaft with the discs is built into a vat. Each disc has separate inlet flow vane and weir for optimised pulp distribution.
42. Preparation of Pulp from Waste Paper Waste Paper Pulper Belt Conveyor Water Chemical Fiberizer Dump Tower Drum Screen Reject Accept High Density Cleaner Hole Screen Stand tube Floatation Primary Cell Venting Cyclone Foam Tank Floatation Secondary Cell Accept Reject CL1 CL2 CL3 CL4 Reject Accept Reject Accept Reject Accept Slot Screen Accept Disc Filter Screw Press Heater Disperger The process in Screw Press, Heater and Disperger is called Dispersion .