The process of making paper is based on the fact that wet cellulose fibers bind together when dried under restraint. The processing of paper usually involves the initial separation of the cellulose fibers to form a wet pulp, some form of treatment, such as beating and refining, while in the pulped state, to enhance the quality of the final product, then forming of the sheet paper by hand molding or by paper making machine, and drying.
Some further processing is often carried out before or during drying to acquire the desired finish.
Some further processing is often carried out before or during drying to acquire the desired finish.
Flow sheet of pulp and paper making process
Raw Materials
Sources of fiber include straw from wheat, barley or rice, bagasse, maize stalks, bamboo, cotton cuttings, lint and fluff, rags (from cotton material), hemp and sisal from old ropes and jute. chemicals required are NaOH, Chlorine and CaO.
The stages involved in transforming raw materials
into paper in a small scale mill are the following operations:
• Delivery and preparation,
• Bleaching and refining,
• Sheet forming,
• Coating, drying & calendaring, and
• Cutting & packing.
Effluent treatment and disposal is another topic, which needs careful attention. The effluent from a paper mill can contain different chemical species, which, if discharged directly into the environment, would cause untold damage. In medium and large-scale plants specialized recovery equipment is used to reclaim chemicals for reuse or for incineration to provide energy. This is not cost effective in smaller plants and so some form of treatment and/or disposal is required. Biological treatment plants, such as the anaerobic digester, are sometimes used to treat the effluent. This method has the added 90 - 10 benefit of producing methane through digestion of the organic matter in the effluent, which can be used to provide as much as 30 % of the mill's energy requirement. The remaining sludge can, then, be disposed off on the land.
List of Machinery
1 Pulper
2 Breaker
3 Beater / refiner
4 Washer
5 Refining equipment
3 Beater / refiner
4 Washer
5 Refining equipment
6 De-flaking equipment
7 Screen
8 Cleaners
9 Fourdrinier machine
10 Headbox or flow-box
11 Press
12 Dryer
13 Reeling, winding and sheeting equipment,
14 Handling equipment
15 Size press Machine
16 Cutting machine
17 Laboratory equipment Set
18 Auxiliary equipment Set
19 Boiler
7 Screen
8 Cleaners
9 Fourdrinier machine
10 Headbox or flow-box
11 Press
12 Dryer
13 Reeling, winding and sheeting equipment,
14 Handling equipment
15 Size press Machine
16 Cutting machine
17 Laboratory equipment Set
18 Auxiliary equipment Set
19 Boiler