Treatment method and equipment of the hottest mixe

2022-08-22
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Mixed office waste paper treatment methods and equipment

with the development of office automation, the number of office waste paper is increasing. Because the office waste paper is composed of inkjet printing, laser printing, electrostatic copying paper, etc., and is made of high-quality chemical wood pulp, it is not only high whiteness, but also good strength, so its utilization value is very high. However, the printing form of office waste paper is different from traditional printing, and it is relatively difficult to remove these inks. The 150t/d mixed office waste paper treatment line newly digested, absorbed and developed by our institute adopts the methods of screening after pulping, deinking, heating and high concentration dispersion to reduce the particle size of ink to the range removed by flotation and washing, and then obtain clean pulp by bleaching, secondary flotation and washing. The yield of secondary fiber size obtained by such treatment is more than 75%, and the whiteness is more than 80 degrees

I. simple process flow:

(1) high concentration hydraulic pulping system

the waste paper is crushed by the high concentration hydraulic pulper at% concentration, then diluted to 4-5% and pre screened by the rougher. The good pulp enters the discharge tank, and the coarse pulp is further processed by the cylinder screen, and the good fiber returns to the hydraulic pulper, while the coarse slag is excluded. The characteristics of the system: discharging pulp and removing impurities are carried out at the same time to keep the pulper tank clean, obtain pre screened pulp, shorten the pulping cycle and improve the production capacity of the pulping system

(2) high and medium desanding screening system

the slurry is adjusted by the concentration in the discharge tank and pumped into the high concentration deslagging device by 3-4% to remove all kinds of heavy sundries (such as metal fragments, nuts, staples, round needles, etc.) in the slurry, and then it is roughly screened through the vertical pressure screen (hole screen). The good slurry is diluted to about 1.5% concentration and enters the medium concentration deslagging device for further slag removal, Coarse slurry (1) after the thermal insulation material of expanded benzene board is removed by the flotation trash remover, the light and heavy impurities are returned to the high concentration slag remover printed and distributed in the special plan for the development of new material industry in Shandong Province (year). The slurry through the medium concentration slag remover directly enters the vertical pressure screen (seam screen) for fine screening system. The fine screening system has three outflow pressure screens. Features: the coarse screening system can remove most of the heavy and heavy impurities in the pulp, and the fiber loss is small. In view of the current decline in the quality of waste paper raw materials, high and medium concentration slag removers are used for two-way slag removal to protect the subsequent screening equipment. The treatment concentration of fine screening is more than 1.5%, so the efficiency of this system is relatively high

(3) flotation deinking system

the slurry enters the laminar flotation deinking system at a concentration of about 1%. The first flotation adopts a 5-stage flotation unit, and the second flotation adopts a 4-stage flotation unit. The flotation system has good flotation effect, less fiber loss, less land occupation, high production capacity, and easy to control

(4) thermal dispersion system

after one-time flotation, the slurry is removed by light slag remover and heavy slag remover (the concentration is about 0.7-0.8%), concentrated to 28-30% concentration by garden thickener and screw extruder, and then enters the double roll thermal dispersion machine with about 25% concentration by mixing screw conveyor. The thermal disperser does not cut off the fiber under the condition of high shear action and reduces the size of impurity particles, so that they can be removed by washing and secondary flotation in the subsequent process section. It has large production capacity and good dispersion effect. In this system, hydrogen peroxide solution is added at the same time, and the thermal dispersion machine plays a role of bleaching and mixing at the same time. Considering the characteristics of mixed office waste paper, the thermal dispersion temperature here is about 7O ℃

II. Overview of main equipment

1. 30 cubic meter high concentration hydraulic pulper

adopts a specially designed three head spiral rotor, the rotor rotates, and the slurry in the slurry tank produces an ideal flow of synthesis from center to circumference, from circumference to center, and from top to bottom and from bottom to top. Under high concentration conditions, the slurry has strong friction and kneading effect, has strong crushing ability, and is also very effective for the stripping of ink particles from fibers, Its high concentration crushing concentration is 12-16%, up to 18%, so it can save steam, chemicals, power consumption, etc. at the same time, it produces less fine fibers, high pulp strength and high whiteness. The design rotor diameter of this equipment is φ 1905, rotating speed 143rpm, tank diameter φ 4600, with power distribution of 500kW

2. The rougher

adopts a low friction four blade hydraulic rotor, and the back design has the function of self-cleaning screen plate, so it can evenly disperse the discharged slurry, keep the screen plate not blocked, and prevent impurities from breaking. The slurry inlet shell of the equipment adopts an upward tilt type, which can keep the rotor from being damaged by heavy impurities, and the whole transmission device can be moved backward. For the maintenance of rotor and sieve plate, the designed slurry concentration of the equipment is 4-5%, and the rotor diameter φ 1220, select sieve plate aperture φ 6. Power distribution: 75kW

3. High and medium consistency slag remover

this slag remover applies the principle of free vortex, which can effectively remove the heavy impurities in all kinds of pulps after mixing for 3 minutes. The slurry flows downward into the slag remover at a specific angle from the tangent direction. When the slurry flow moves along the inner wall in a spiral way to the slag discharge port, centrifugal force is generated. Impurities in the slurry such as gravel and metal blocks are thrown to the inner wall under the action of centrifugal force and discharged downward from the lower port into the sediment chamber. In the sediment chamber, the slurry is further cleaned, the fibers are recovered, the waste residue is deposited at the bottom of the slag chamber, and the good slurry is spiraled upward, Discharge from the guide pipe at the top of the slag remover. The cone part is composed of an external steel shell and an internal ceramic upper and lower cone. The upper cone is a centrifugal slag removal area, the upper section of the lower cone is square, and the lower cone is circular. The coarse slag separated by the upper cone flows into the lower cone, gradually decelerates and is cleaned. The coarse slag sinks into the sediment chamber, and the fibers return to the slurry flow, so the fiber loss is low, and the whole slag remover will not be blocked. High concentration slag remover, with a throughput of 7500-1000ol/min and a slurry concentration of 3% - 6%; The medium concentration slag remover has a throughput of 5000-7500l/min and a slurry concentration of 1% - 2%

4. The vertical pressure screen

adopts the upflow structure design, the bottom is fed with slurry, the light impurities and the air in the slurry naturally rise to the top slag discharge port and are quickly discharged out of the machine, and the heavy impurities settle to the bottom and are discharged, which greatly reduces the possibility of rotor and screen drum damage. The upflow structure also eliminates the vortex that causes the vibration, impact and stress of the screen body. The segmented shell is adopted, and the outlet direction of good slurry can be adjusted. The coarse screen adopts a closed non winding wood plastic composite new material, which inherits the double advantage rotor of plastic and plant fiber. The rotor blade can be replaced after wear without replacing the whole rotor. The fine screen adopts the rotor, the structure shape of the rotor is optimized, the rotation speed is selected reasonably, and the positive and negative pulses are generated, so as to achieve the purpose of self-cleaning the screen holes (seams). Adopt corrugated% sieve plate to increase output and improve screening efficiency

① coarse screen: nominal screening area (hole screen): 1.2 ㎡

screen slurry concentration

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