The causes of pulp decay in papermaking process and its control methods

Slurry is the result of the multiplication of bacteria and molds. The carbohydrates in the pulp, a small amount of protein, and hydrolyzed sugars are all nutrient sources for microorganisms, especially organic wood pulp. Since wood contains about 5% of low-molecular sugars, they are deeply resolved after grinding. The white water is more conducive to the reproduction of bacteria. Generally, the white water contains bacteria. In the warm season, they can be found in the dead corners of the slurry tank, the elbow of the pipeline, the open screen slurry machine, the white water tray, the flow box, the white water pit, the water-sealed pool, etc. On the walls of the container, as well as in the open slurry flow path where the flow rate is slow or where there is sediment, reproduction occurs and mucilage is produced. These mucilages, bacteria, foam scum, fibers, etc. form a sludge mass. When the liquid level of the slurry fluctuates, these sludge masses will fall off and fall into the slurry. Yellow or green pulp spots or holes are formed on the paper surface, and even breakage occurs during pressing. The following measures can be taken to prevent sludge: 1) Improve the process and equipment a. Try to simplify the feeding system before the paper machine to reduce or shorten unnecessary processes. The system should be sealed, that is, airtight purification and screening equipment should be used. Pay attention to frequently vent the trapped air in the sealing system. b. Improve the liquid flow path of the slurry tank and white water pit. So that it does not produce rot and slurry, thereby eliminating dead corners. When installing the flange, pay attention to making the joint not easy to hang grout. c. Try to increase the flow rate of each part of the material without affecting the operation of the paper machine. d. Use smooth and corrosion-resistant materials such as plastic, rubber, copper, etc. 2) Use fungicides, isothiazolinones and organic bromine fungicides. A more effective method is to use organic bromine sterilization in the water treatment system, and the general concentration is 15%, which can control the growth of bacteria. Achieve the desired effect. 3) Clean the equipment regularly to keep the system clean. You can also use a solution for complete cleaning.