The Pulp Washing Process in Paper Manufacturing: Paper is produced from the plant material called cellulose which is found in all plants. Paper is also made from waste paper initially made from trees by the complete process of paper manufacturing. For making the paper firstly raw wood is required that is turned into pulp. The pulp comprises mixed wood fibers and chemicals and can be processed mechanically, chemically, or semi-mechanically. In this blog, we give knowledge about “The Pulp Washing Process in Paper Manufacturing”. If You know How and why we wash pulp then this article will be helpful for you.

Complete the Process of Pulp Washing for Paper Manufacturing 

Pulp washing processing is a crucial process in paper pulp production. Pulp washing is the separation of the slurry and black liquor, so that washed out alkali lignin and other impurities from the reaction in the cooking processing, and purifies the pulp, which is helpful for filtration and bleaching. As for the procedure of pulp washing processing, including single-stage washing, multi-stage washing, and multi-stage countercurrent washing. But Multi-stage countercurrent washing is the best way that is chosen by the various paper manufacturing companies.

Pulping

The first step of the pulp washing process is obtaining the dirty pulp which is derived from the wasted paper and wood chips. The pulping process divides this material into various fibers for the next steps.

Formation of Pulp Mixture

After producing the pulp this mixture is collected from various impurities. This mix is the starting point for making our paper, but we need to clean it up by removing those unwanted bits before moving forward.

Add the Water

Now the mixture of pulp goes to the next step of the washing process where the water is added into the mixture to separate all impurities of the pulp mixture. This step is crucial because the mixture of impurities in pulp affects the properties and quality of the paper.

Washing Method: 

This process is completed in two types:

1. Gravity Washer: Water and pulp are separated by these using gravity. The mixture of pulp and water moves through a series of inclined channels or screens, leaving behind cleaner pulp.
2. Pressure Washer: In this method, water is constrained through the pulp under pressure. The expanded pressure speeds up the washing process, really eliminating impurities.

Removal of All Impurities

As water is presented and circulated, it diverts unwanted components like remaining synthetic material, lignin, and different impurities. Clean pulp with the desired fiber quality is the objective of this process.

Final Pulp Item

Clean pulp with improved fiber quality is the outcome of the washing procedure. This filtered mash is then prepared for the ensuing stage of papermaking, like refining, shaping, pressing, and drying.

Some Related Equipment is Nessery for This Pulp Washing Process

During the washing process, some washing equipment is necessary to complete this process and provide pure and clean pulp. Here is the list of equipment used in the pulp-washing process in paper Manufacturing.

• Pressure washing machine 
• Screw pulping machine 
• Double roll pulping machine 
• Horizontal belt vacuum washing machine
• Circular net thickener
• Side pressure thickener 
• Vacuum washing machine 
• Drop pulping machine
• Pressure washing machine
• Sink

Types of Pulp Washing Methods in Paper Producing

Paper pulp washing is the most common way of dissolving the non-stringy solvent substances in the cooking fluid and sticking to the outer layer of the fiber by water or weakening squander fluid, and isolating them from the fiber, to acquire a clean paper pulp.

This process is prepared by the various types that are given below.

1. Vacuum Drum Washing

Vacuum Drum Washing is the most favored method in the paper industry that consists of three to six stages.  Each stage has a rotating screen drum that has a partial vacuum applied to the interior. The drum is set in a tank where the pulp is diluted with the recirculated filtrate. The vacuum pulls a pulp mat against the surface and washes water through the mat. The drum rotation pushes the washed pulp mat to the next stage. Wash water removed from this washing stage is sent to the previous washing stage. 

2. Pressure Washing

Pressure washing is another type of method for washing pulp that works similarly to vacuum drum washing. Some steps differ in this method by spraying water under pressure through the pulp mat as the drum rotates. A pressure washer is more complex to run than a vacuum drum washer.

3. Diffusion Washing

Diffusion Washing is a counterflow process that is prepared in one or more stages. The pulp flows upward and is shifted on a perforated plate with  Water flowing downward through a series of baffles. This washing method offers a high degree of cleaning with low water use.

4. Belt Washing

This method is also a type of washing the pulp for paper manufacturing. In This method, pulp enters the washing area on a wire belt, and a row of showers wash the pulp. Clean water enters the opposite end of the pulp and is sprayed on the pulp to replace the liquor in the pulp mat.

Benefits of Pulp Washing Process in Paper Manufacturing

• To Recover the maximum amount of cooking chemicals.
• For Dissolved wood components with the least amount of freshwater.
• To make bleaching easier and more effective.
• Reduce the cost of chemicals and steam.
• Reduce the volume of bleach effluent.

In Conclusion, we explained how the pulp washing process in paper manufacturing works. We hope this information has been helpful to you. RP Paper Impex is a reputed Paper Manufacturing Company in India that gives various types of paper and paper items. All the products are manufactured by the well process and following the pulp washing process to maintain the quality of the final products. If anyone wants to know about this top paper company they can easily contact us and get the manufacturing services for paper.