Coated white board pulping process low in energy consumption

Abstract

The invention belongs to the technical field of coated white board pulping methods. A coated white board pulping process low in energy consumption is in separated and segmented pulping mode and comprises surface pulp pulping, lining pulp pulping, core pulp pulping and bottom pulp pulping. Bottom pulp and core pulp respectively undergo intermediate-concentration continuous disintegration, and the concentration is 4-5%; lining pulp undergoes high-concentration disintegration, and the concentration is 13-18%; when the beating degree of surface pulp reaches or exceeds 45 degree SR at any production stage, knife-adding pulping is not performed, and pulp is only defibered to pass through a production line; and when the beating degree of the lining pulp, the beating degree of the core pulp and the beating degree of the bottom pulp reach 35 degree SR at any production stage, knife-adding pulping is not performed, and the pulp is only defibered to pass through the production line. A mode completely different from the tradition is adopted in the coated white board pulping process, corresponding adjustment is performed on several key control indexes, and not only is energy consumption reduced, but also follow-up papermaking quality is improved.

Description

technical field [0001] The invention belongs to the technical field of slurry preparation technology for coating white paperboard. Background technique [0002] Waste paper production-oriented papermaking enterprises all need thermal dispersion system to process the slurry to improve the quality of the finished paper. The kneading heat dispersing system uses a combination of oblique screw and pressing screw to concentrate the pulp, which is the mainstream configuration of domestic papermaking enterprises. It requires a pulp concentration of 3.5 to 4.5%, and it can reach more than 28% after concentration. The initial effect of the device is not bad. However, after several years of operation, the pulp concentration can only be maintained at 16-18%. The main reason is that the screw used for thickening and the screen drum for dehydration are worn out, resulting in a larger gap between the screw and the screen drum, which is harmful to the slurry. The effect of extrusion and c...

AI Technical Summary

Problems solved by technology

However, after several years of operation, the pulp concentration can only be maintained at 16-18%. The main reason is that the screw used for thickening and the screen drum for dehydration are worn out, resulting in a larger gap between the screw and the screen drum, which is harmful to the slurry. The effect of extrusion and concentration becomes worse, reducing the pulp concentration; second, the output of the papermaking workshop continues to increase, resulting in a relatively low thermal dispersion processing capacity. In order to ensure the supply of core pulp, generally choose to enlarge the outlet and sacrifice the concentration. As the gap between the screw and the screen drum in the previous article becomes larger, the passing speed of the pulp is further slowed down, thus forming a vicious circle; third, the number of domestic waste paper recycling continues to increase, the freeness of the pulp decreases, and the fibers are too short, making The dehydration of the pulp decreases, and at the same time too much short fiber blocks the screen drum, which seriously affects the processing effect of the screw extrusion equipment

[0003] The emergence of the above situation has seriously affected the normal production of the workshop, which is mainly reflected in the following aspects: (1) The concentrated concentration is too low, resulting in poor rubbing effect of heat dispersion, ink dots and ink remaining in the slurry There are more wax spots, which will reduce the dehydration efficiency of the forming wire during papermaking, increase the probability of paper web breakage, and affect the normal production of the paper machine and the stability of the quality of the finished paper

(2) Because the slurry concentration is too low, the moisture carried in the slurry passing through per unit time will increase, resulting in a large proportion of the steam consumed by the thermal dispersion system when heating is consumed in the heating of water, and the equipment The temperature rise caused by kneading the slurry also becomes less noticeable, both of which lead to a significant increase in the steam consumption of the thermal dispersion system

Especially for waste paper pulp, the source is complicated and the quality fluctuates greatly. If the beating degree is not controlled properly, it will have a great impact on paper quality and energy consumption.

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