Pulp paper machinery plays key roles in the pulping process. And then, what pulp paper machine is needed in the pulping process? The article will introduce some useful knowledge to you!
What is Pulping Process
Pulping is the process of making raw material of plant fiber get dissociated and converted into unbleached or bleached pulp by use of chemical or mechanical methods or a combination of both methods.
Pulping is the first step of paper making. Common production methods include: mechanical pulping method, chemical pulping method and semi-chemical pulping method. The basic pulping sequences are: raw material storage→ debarking and knotting→ chipping→ cooking→ washing→ screening and purification→ unbleached pulp (Or→ bleaching→ pulp board bleaching) → impregnation and refining.
In addition, the pulping process also includes some auxiliary processes, such as the preparation of cooking liquor, the preparation of bleaching solution, the recycle of the cooking waste gas, chemical and heat energy in waste liquor and comprehensive utilization of waste liquor.
Current Situation of the Pulping Industry
According to the Food and Agriculture Organization of the United Nations (FAO), global pulp yield is 181 million tons in 2015. North America, Europe and Asia are still three main regions of the largest pulp production. Their yields are respectively 65.504 million tons (36.2% of global yield), 45.588 million tons (25.2% of global yield) and 39.71 million tons (21.9% of global yield). Latin America is in rapid growth. Its yield reached 25.376 million tons (About 14% of global yield) in 2015. It has become the fourth largest pulp production area. According to data quoted from China Paper Association, the total pulp yield of China was 79.25 million tons in 2016. However, the total amount of imported wood pulp is 18.81 million tons. So the import dependence reaches 65.1%.
Pulp Paper Machinery
Pulping equipments are used to achieve the machines of carrying out the pulping process. Main equipments include: hopper, sand separator, agitator, vibrating frame flat screen, pressure knotting machine, fine screen for each stage, digester, heat exchanger, blow tank, vacuum pulp washing machine, reaction tower, bleaching tower, conditioner, standpipe, heater, mixer, pulp storage tower, condensate system, waste gas collection and condensate system, recycle system, pulp board machine, pulp board cutting machine, baler, accessory tanks and valves, etc.
To a large extent, the science and technology referring to the pulp paper machinery can affect and determine the development of the pulp industry directly. In recent years, China's pulp industry has been developing rapidly in line with international standards. Except for structural adjustments of raw materials, the pulp industry has benefited mainly from the improvement of relevant equipments. Currently, paper pulp machine manufacturers have been working hard for better pulp paper machinery. They have manufactured many advanced pulp paper machines in China. Pulp paper machine price is reasonable and relatively low.
The following focuses on three types of pulping equipments:
Vacuum drum pulp washing machine
Vacuum drum washing machine is a kind of common washing equipment and suitable for wood pulp, straw pulp and other pulps. It is key technology and equipment to solve waste water pollution and implement the alkali recovery project the paper industry. It is an important pulp paper machine.
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A. Features of vacuum drum pulp washing machine:
During the drum makes one revolution round, the washing machine can complete three processes of filtration, washing, stripping. It is widely used for various pulp extraction and bleaching stages in the pulping and papermaking enterprises. After the washing, pulp has low alkali residue content and can get higher extraction rate of black liquor, which has favorably promoted the alkali recovery of papermaking industry and control black liquor pollution. -
B. Structure of vacuum drum pulp washing machine:
It is mainly composed of drum, tank, plane distributing valve, washing device, stripping device, net washing device, transmission device, screw conveyor, etc. It can be used in single or serial way. -
C. Working principle of vacuum drum pulp washer:
The drum rotates in the tank with the pulp. For each revolution round, each outlet will pass through the vacuum filtration zone, the stripping zone and the exhaust zone successively. Due to the vacuum suction function, the liquor in the pulp will be extracted away from the filtrate flow path and the distribution valve and adsorbed on the outer surface of the drum body, achieving the processes of extracting, filtrating, stripping and gas exhausting.
Twin roll press machine
Twin roll press machine is a kind of high-efficiency washing and concentrating equipment by adopting the displacement squeezing principle. The pulp washing and dewatering woll press machine is used for the washing of primary pulp and the extraction of black liquor. It can also be used as washing or concentration of bleached pulp. It is suitable for chemical pulp, mechanical-chemical pulp and waste pulp and other pulps of the large-scale production line. The product performance is reliable, and the operating indicators have reached advanced international level.
The pulp is discharged into it along the surface of the rolls to form a pulp layer filter. The pulp layer can be pressed to the required dryness by passing through the area between two rolls. The pulp dryness is affected by roll pressure, roll speed and the area size. Out of the press zone of two rolls, the pulp layer will be scraped off by the scraper and taken away by the screw conveyor. Then the pulp is roughly broken up and delivered to the outlet of the screw. Next, the pulp will be transferred to a chute or screw conveyor for the next treatment as required.
Pulp paper machinery is one of main products of CNBM. As one of professional paper pulp machine manufacturers, our pulp paper machine price is lower but the quality is better. So our products have been widely used at home and abroad. Welcome to contact with us freely, we will response you at once.
