Pulp Washing

Pulp Washing

Pulp washing is a very crucial process in pulping production. It is the separation of the pulp and black liquor, and very helpful for filtration and bleaching. Pulp washer is a kind of pulp washing equipment.

Pulp washer is used for extracting black liquor from pulp. The purpose of washing is to wash the pulp and increase the extraction rate of black liquor and create conditions for chemical recovery. Therefore, the washing index has the following two points: washing degree and extraction rate.

vacuum drum washer
vacuum drum washers

Vacuum pulp washer

Vacuum washer is a kind of common pulp washing equipment. It is suitable for various pulps such as wood pulp, straw pulp and so on. It is key technical equipment for the paper making industry to solve the wastewater pollution and implement the alkali recovery project. It is mainly composed of drum, tank body and plane distribution valve, washing device, stripping device, screen washing device, transmission device, screw conveyor, etc. It is composed of a single unit or a group in series.

Pressure pulp washer

Pressure washer is a new type of pulp washing equipment. Its main features are: the operation under sealing and positive pressure; the adaptability to the feeding amount and concentration; not easy to fall off the screen and be stacked up; be allowable for higher washing temperature to reduce heat loss and improve black liquor temperature; not easy to produce vaporization and foam of the filtrate. It consists of a drum, a drum sealed groove, sealing rolls and an outer casing.

Displacement pulp washer

Displacement washer is an original meaning of “diffusion washer” in English, so the equipment is also called diffusion scrubber. However, with the in-depth study of the pulp washing principle, it is considered that the washing process of this equipment is completely a displacement process.

Twin roll displacement press pulp washer

Twin roll displacement press washer is a pulp washer that combines three functions of dilution, dehydration, displacement and pressing. It can effectively remove soluble solids in the pulp, reducing the bleaching chemical consumption.

Displacement drum washer

Displacement drum washer is referred to as DD washer. It is divided into multiple sections for washing on one rotary drum, and one washer can complete all washing work. It has the characteristics and advantages of vacuum washer and pressure washer.

Through the above introduction, we believe that you’ve known much relevant knowledge about pulp washing equipments. We hope that you can send your inquires for further setting up the cooperation and business with us!

Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fiber crops, waste paper, or rags. Many kinds of paper are made from wood with nothing else mixed into them. This includes newspapers, magazines and even toilet paper. Pulp is one of the most abundant raw materials.

A pulp mill is a manufacturing facility that converts wood chips or other plant fibre source into a thick fibre board which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical or fully chemical methods (kraft and sulfite processes). The finished product may be either bleached or non-bleached, depending on the customer requirements.

A paper machine (or paper-making machine) is an industrial machine which is used in the pulp and paper industry to create paper in large quantities at high speed. Modern paper-making machines are based on the principles of the Fourdrinier Machine, which uses a moving woven mesh to create a continuous paper web by filtering out the fibres held in a paper stock and producing a continuously moving wet mat of fibre. This is dried in the machine to produce a strong paper web.

The pulp produced up to this point in the process can be bleached to produce a white paper product. The chemicals used to bleach pulp have been a source of environmental concern, and recently the pulp industry has been using alternatives to chlorine, such as chlorine dioxide, oxygen, ozone and hydrogen peroxide.

Chemical pulp is produced by combining wood chips and chemicals in large vessels called digesters. There, heat and chemicals break down lignin, which binds cellulose fibres together, without seriously degrading the cellulose fibres. Chemical pulp is used for materials that need to be stronger or combined with mechanical pulps to give a product different characteristics. The kraft process is the dominant chemical pulping method, with the sulfite process second. Historically soda pulping was the first successful chemical pulping method.