SU44877A1 - Apparatus for refining cellulose, paper pulp and similar products - Google Patents

Description

The invention relates to the field of refining paper (wood pulp) or a material similar to it and mainly provides apparatus for carrying out the refining process, in which hydrolysis is eliminated due to the almost complete absence of stirring, and the loss of fibers is eliminated due to the fact that masses having a liquid consistency are used shallow tanks. The term "liquid mass" refers to a mass containing no more than 15% fiber, although, depending on the nature of the mass, this percentage may vary.

The usual technique used so far in the practice to eliminate the precipitation of fibers from the liquid mass is that agitators were installed in an ordinary refining chamber. Such mixing is disadvantageous from the point of view of energy consumption and the cost of maintaining the apparatus, and also has a harmful effect on the mass, causing hydrolysis of the cellulose and material loss associated with this hydrolysis. The main objective of the present invention is to overcome these difficulties by means of apparatus for a liquid mass that works easily and at the same time without the disadvantages resulting from

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loss of fibers and from stirring, in which, in addition, there is a significant saving in initial costs and expenses for its maintenance.

Although the apparatus can be applied in general for all kinds of mass refining operations, which require a more or less prolonged mass stay in contact with the refining reagent, an apparatus that is used mainly for mass bleaching is given in this description.

According to the invention, a relatively long downwardly inclined channel or passage through which a fluid mixture with bleaching agent, under the influence of its own weight, is forced to flow, is provided. In this way, no deep layers of liquid masses are formed and due to this, no fiber precipitation is observed, despite the absence of stirring.

Mixers are installed at the inlet end of each channel for the liquid mass, and at the outlet ends of the mass discharge regulators from the channel. Both mixers and regulators are designed in such a way that they do not produce noticeable stirring or mass loss.

The drawing schematically shows an exemplary device of one embodiment of the invention, with FIG. 1 shows a vertical cross section along line 1-1 of FIG. 2, and FIG. 2,3, and 4 are horizontal cross-sections along lines 2-2, 3-3 and 4-4 of FIG. one.

In the example shown, the device consists of a building with walls 7, floors 2, 3 to 4 and a roof 5.

Above the upper floor 2, a flow tank b is installed (Fig. 3), containing a stock of mass or other material intended for bleaching. The tank 6 is connected by a tube 7 to a mass density regulator 8, from which the mass passes into the mixer 9. Tank} 0, which contains a supply of bleaching reagent, is connected by tube // to mixer 9 and, similarly, pipe / 5 connects mixer P to the tank 72 containing hot water.

Tanks 6, JO and / 2 (Fig. 3) can be conveniently placed on an elevated platform 4, which can be reached from the floor 2 along the ladder / 5.

Under the mixer 9 there is a cylindrical bleaching tower / b for a mass of thick consistency, the bottom of which is provided with an outlet / 7. An instrument 18 is installed at the bottom of the turret / b, which facilitates and regulates the passage of mass through the aperture / 7 with almost no mechanical stress. Through chute 79 and passage 20, hole 77 is connected to tank 2 /.

The pick-up end of the pump 22 is connected to the tank 27, and the pumping end of the pump is connected by a pipe 23 to a tank 24 mounted above the upper floor 2.

The tank 24 is connected by a pipe 25 with a washer and a mass density regulator 26, from which the mass enters the conveyor belt 27, which supplies it to the mixer 28.

From the mixer .28, the mass enters the upper end of a long shallow inclined bleaching channel 29 intended for a liquid mass that is curved to save on floor space. In the example shown, the channel consists at one end of a semicircular (in horizontal projection) channel, passing into straight lines

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solid channels, which further transfer to a new semi-circular channel of smaller diameter, surrounding the tower 76. From the bleaching channel 29, the mass passes through the regulator 30 to the tank 57, which in turn communicates with the mass washer 32 installed on the floor 3; from the washer 32, the mass enters the conveyor 33, the conveyor supplies it to the mixer 34, from which it passes into the channel 55, arranged in this example, exactly the same as channel 29 and located directly below the latter.

From channel 55, the mass passes through regulator 56 (and, if necessary, through a new washer, not shown in the drawing) to the third bleaching channel 57. liquid mass of the same device with channels 29 and 55. From channel 57 the mass passes through regulator 38 a collection box or tank 39 located on the lower floor 4 (FIG. 4), from which it can be pumped by pump 40 to any receiver for further processing.

FIG. 4, 47 is the closed box for the water column of the density regulator 8 and, if necessary, a similar box 42 for the water column washers 26 and 52 can be arranged.

It should be borne in mind that the drawings have a schematic character, and that individual pieces of equipment, such as washers, mixers, and regulators, have a cusp of lime construction per se. Adaptations may also be provided for introducing any white protein reagent s mixers after any stage of the process.

The shape and location of the bleaching channels for the liquid mass can also be modified in various ways, without departing from the principle of the invention. The only essential requirement is that these channels allow the mass to flow evenly downward under the effect of its own weight in a shallow layer, in order to avoid sedimentation of the fibers on the bottom.

The effect of the described equipment is as follows. The material flows from box 6 through pipe 7 to density regulator 8, in which the mass is brought to a relatively high degree of density, for example, to 20% and higher. From here, the mass continuously flows into mixer 9, where it is mixed with bleaching reagent coming from tank W and, if desired, with hot water from tank 12. From mixer 9, the mass falls into the bleaching tower 16 for the thick mass through which it moves under its own weight.

A slowly rotating device 18 controls the passage of material through the opening 17, not the cause of noticeable mechanical stress.

The mass then passes through the opening 20 to the tank 27, from where it is pumped to the tank 24, from the tank 24 to the washer and density controller 26, in which the mass is diluted to a liquid consistency. The mass is then transferred by conveyor 27 to a mixer 28 into which a bleaching agent can be simultaneously introduced. From the mixer 28, the mass flows in a shallow layer along the inclined floor of the channel 29. The mass output from the channel 29 is controlled by the regulator 30, which does not cause noticeable mechanical losses or mixing of the mass. Thereafter, the mass is washed in washer 32 and transported by conveyor 33 to mixer 34, where a new portion of bleaching reagent can be added to it, and then flows through inclined channel 35 to regulator 36 and, finally, through channel 37 through regulator 38 assembly tank 39.

After the last or after any of the intermediate stages of bleaching, a reagent that removes or neutralizes the reaction products formed during the bleaching process or removes excess residues of the bleaching reagent can be added to the mass. Lime milk, caustic alkaline solutions, etc. can be used as the reagent. A device for introducing this reagent can be a pipe 19a., Feeding the reagent into the chute 19, below the bottom of the tower / 5. Similar adaptations may, if desired, be arranged after any of the stages and after each stage of the bleaching process.

Instead of introducing hot water from tank 12, it is possible in addition to this water to facilitate bleaching to inject either air, steam, or any other liquid or gaseous medium intended for temperature control. Air has the advantage of not diluting the bleaching solution. FIG. Figure 1 shows a device for this business consisting of a pipe / 2a entering the mixer 9. Similar devices may be arranged at the starting points for the additional bleaching agent and, if desired, at other places. The control medium can be introduced into the controllers 30 and 36. If the temperature of the mass after the end of one process stage is too high to get the best performance in the next stage, cooling medium is introduced and vice versa.

The described sequence of operations can, of course, be changed depending on the variety of the treated mass. Any stage can be turned off from the process or you can add extra stages. The equipment is easily changed in such a way as to dispense with the stage of processing the mass of a thick consistency or to include this processing after one of the processing stages in a liquid consistency.

A suitable mixer is described in U.S. Patent 1,767,102 on the same article.

Although the apparatus described above provides for its special use for pulp bleaching, it can nevertheless be equally used for bleaching and other materials similar to it.

In the same way, the described apparatus can, of course, be applied to other mass refining processes in addition to bleaching, and its action in this case can easily be understood from the description described in relation to bleaching.

The subject matter of the invention.

1. A device for refining (bleaching) cellulose, paper pulp and similar products, characterized in that in order to achieve a continuous process a) to obtain a uniform consistency of fibers at a certain concentration of them in a mixture with reagents in certain stages of processing, b) changes or preservation of the fiber concentration when re-introducing the applied or introducing a new

reagent and c) introduction of agents that change the temperature of the environment of the fibers being processed, applied concentration controllers 8, 26, 32, mixers 9, 28, 34, producing the material to be treated — first into the tower / b in the case of bleaching, in a concentrated state, and subsequent channels, 29, 35, 37, long, shallow, winding with an inclination downward, directing it by gravity from the above-mentioned mixers to the controller-washers located in the lower floors and the hot water tank 72 connected to the pipe 75 with mixer P (Fig. 1, 2.3). 2. The form of execution of the device indicated in clause 1, characterized in that the above equipment is located in a building of several floors, in which tower J6 is located between the floor f y

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mi, goes around channels 29, 35, 37, which, in order to preserve the area of the building, is given a meandering direction (Figs. 1, 2, 3).

3. The form of implementation of the device mentioned in claim 1, characterized in that for moving the processed material from the density controllers and washers 26, 32 to the mixers 28, 34, in order to eliminate fiber loss, non-working conveyors 27 are used, 33 (Fig. 1, 2, 3).

4. With this device, use instead of tanks with combustible water to obtain a certain temperature of the mixture of the processed material with the reagent of steam or air tanks equipped with a steam or air duct opening at the mixer 9 (Fig. 1).

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