JPS5853115B2 - Method and apparatus for processing fibrous materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a liquid-permeable screen element that is moved in an endless passageway sequentially along a web forming zone, a washing zone, a processing zone and a press zone to form a fibrous suspension of cellulosic material. The liquid is supplied to the web forming zone Q, the fibrous material suspension is dehydrated on the screen element to form a fibrous material web, and the fibrous material attached to the web forming zone is shaped or adhered to the screen element. cleaning the fibrous material web in the washing zone during subsequent compaction of the material web, supplying the fibrous material web 6 with a treatment liquid in liquid or gas phase in the processing zone, and compressing the fibrous material web in the pressing zone. The present invention relates to a method for continuously processing fibrous material (fibrous pulp).

The present invention also provides a body surface (
a rotating drum having a shell ), an internal liquid disposal device and a drive and speed control device, and a casing covering at least a substantial part of the drum, the casing having a gap G with the drum.
A web-forming zone with an inlet device for the fibrous suspension successively along the drum rotation direction G and at least one web-forming zone located outside the casing through the perforations of the casing.
a cleaning zone communicating with two cleaning fluid chambers; a processing zone communicating through a perforation in the casing with at least one chamber located outside the casing;
It also relates to an apparatus for carrying out the method, in which a rotating press roll defines, together with the body surface of the drum, a press zone which defines a press nip.

In the field of pulp manufacturing, the treatment of cellulose fibrous pulp requires different types of treatments, such as bleaching and washing.

Bleaching of pulp requires several steps, and a reaction agent is supplied for each step.

Swedish Patent No. 357,779 describes such treatment in detail in different steps and compares the results obtained with high and low concentration bleaching.

Swedish Patent No. 350,290 describes a device for exchanging one liquid contained in paper pulp with another liquid.

However, there are drawbacks to using the apparatus described in this patent for processing fibrous pulp.

This treatment had to be carried out at relatively low pulp concentrations, estimated to be up to 12 g.

Limb exchange also occurred from both sides of the fibrous cake sandwiched between two perforated feeder bands.

The treatment liquid was fed into the fibrous cake and mixed with the liquid contained in the cake before the liquid mixture was removed from the cake.

This treatment diluted the liquid contained in the fibrous cake and removed some of the diluted liquid.

The purpose of the present invention is to prepare a liquid or gas phase treatment liquid at a high concentration (1
To provide a method and apparatus that can quickly and easily feed and impregnate fibrous pulp having a diameter of 8 to 50 φ), without the disadvantages of using conventional known methods, or at least essentially reducing them. It is in.

The problem to be solved by the present invention is how to quickly apply a liquid phase or gas phase treatment solution to a fibrous pulp having a high concentration (18 to 50φ).
The problem is how quickly the liquid can be dispersed into the pulp so that it comes into contact with each fiber.

The present invention solves this problem by the method indicated in the claims.

The present invention has several advantages particularly when used in a method for bleaching fibrous pulp.

When a fibrous pulp with a high concentration is impregnated with the reactive agent used in the bleaching process, the reaction occurs more rapidly than at lower concentrations.

The said Swedish Patent No. 357,779 is 3 in Table 1.
Bleaching of pulp with a concentration of 0g (high concentration) from 3 to 12
A comparison is made using the same bleaching method for the same type of pulp having a concentration of φ (low concentration).

This comparison shows that the total reaction time was 600 minutes at the low concentration, whereas it was only 63 minutes at the high concentration.

Furthermore, chemical consumption at high concentrations was only about 56% of consumption at low concentrations.

Reduction of the reaction time to less than 10 times the time at low concentrations means that the pulp volume that has to be accommodated in the bleachery can be reduced considerably.

As a result, the equipment and processing vessels required for the bleaching process can be substantially reduced in terms of volume G.

Most processing steps require that the fibrous pulp be maintained at a relatively high temperature of 70-100°C.

At high pulp concentrations, less heating energy is required compared to the energy consumption of conventional bleaching at lower concentrations.

The invention is also applicable to the heating or cooling of fiber pulp, for example to high concentration melting.

Heating can be carried out in a simple manner at high concentrations and requires less energy consumption.

Other features of the invention and the advantages obtained by it can be better understood by reference to the following description of exemplary embodiments in conjunction with the accompanying drawing figures.

The embodiment of the invention shown in FIG. 1 has a surface or shell formed as a liquid-permeable screen element.
l) Consists of a rotating drum 11 with 13.

The drum 11 is mounted on a device pedestal (not shown in the figure) with a bearing 15.
It is mounted on a G shaft and is equipped with a drive and speed control device 17.

An outer shell or casing 19 is attached to the outside of the drum 11 and defines an enclosed space 21 between the casing and the body surface 13 of the drum 11.
The radial distance from drum 1 to casing 19 is
1, it decreases from the starting point of the space 21 toward its ending point, as measured in the direction of rotation of the space 21.

At the beginning of the space 21 within the casing 19 a controllable fibrous suspension supply device 23 is mounted and arranged to introduce a substantially uniform flow of suspension over the width of the barrel surface 13. It is.

The first part of the space 21, measured in the direction of rotation of the drum 11, serves as a web-forming zone 25, and next to the zone 25 in this space 21, in order in the direction of rotation, a cleaning zone 27, a compression zone 29. , processing zone 31 and press zone 33
It is continuing.

The casing 19 is perforated along the washing zone 27 and the processing zone 3H.

There is a cleaning liquid chamber 35 on the outside of the casing 19 along the cleaning zone 27 for supplying cleaning liquid through the perforations in the casing 19 .

A further chamber 37 runs along the processing zone 3H of the casing 1
The processing liquid is supplied through perforations in the part of the casing which extends along the processing zone.

The cleaning liquid chamber 35 is equipped with a supply device 39 that includes at least one servo-controlled valve 41 .

Connected to the chamber 37 is one or more supply conduits 43 with server control valves 45 .

A rotating press roll 47 is mounted between the washing zone 27 and the processing zone 31, which press roll has a liquid-impermeable surface and, together with the body surface 13 of the drum 11, defines the compression zone 29.

A press roll 49 with a liquid-impermeable surface is attached after the processing zone 31.

The press rolls 47 and 49 are mounted on the same device base as the drum 11 with bearings 51 and 53, respectively.
Together with the body surface 13 of the drum 11, these define press engagement keys 55 and 57, respectively, which have a substantially constant gap width during operation.

The bearing 53 of the press roll 49 is, for example, a strain gauge (
The pressure gauge device 59, such as 5 train gauges, is equipped with a pressure gauge device 59,
57 is arranged to provide a signal indicative of the linear pressure.

After the press meshing part 57, there is provided a removal and feeding device 61 consisting of a cover 63 that covers a screw 65 for both crushing and feeding.

This cover 63 has a doctor blade 67 and a press roll 49 that are in close contact with the surface 13 of the drum 11. This includes a sealing device 69 that is tightly sealed.

One or more steam supply conduits 71 with valves 73
is connected to the cover 63.

The supply device U is equipped with a connecting flange (not shown) at the outlet end of the device, arranged for sealing connection to the subsequent processing device.

A control device consisting of a pressure gauge device 59, a drum speed control device 17, a control valve 41 of the cleaning liquid chamber 35, and a control valve of the chamber 37 are connected by means of conductors 77, 79, 81 and 83, respectively, to control the web forming operation. and installation to control cleaning and processing operations.

The specific type and assembly of the components of this control device, and the device as a whole, may be determined by those skilled in the art (and thus, as a matter of ordinary skill in the art, using various known electrical, hydraulic, pneumatic or You can choose from mechanical elements and equipment.

Outlet 8 for disposing of the liquid drained into drum 11
It is equipped with 5.

The above device operates as follows.

A constant amount of suspension of fibrous material per unit time under pressure is fed through the feed device 23 to the web forming zone 25 of the space 21, while the drum 11 rotates at a substantially constant speed.

Due to the pressure difference between the space 21 and the inside of the drum 11, the suspension liquid 89 passes through the body surface 13 of the drum 11 and
A fibrous web 91 is formed on top.

The thickness of the fibrous web gradually increases as it moves through the web forming zone 25 until it completely fills the space between the barrel surface 13 and the casing 19.

Owing to the convergence of the spaces 21 in the direction of rotation of the drum, the fibrous web 91 then moves towards the compression zone 29 (gradually compressed, the suspension liquid spills over the barrel surface 13). passed through and squeezed.

As the fibrous web passes through the washing zone 27, the casing 1
A constant amount of cleaning liquid per unit time is forced into the fibrous web 91 under pressure through the perforations 9 .

As a result, the cleaning liquid 93 removes the suspension liquid 89 remaining in the fibrous material web 91 from the line A in the fibrous material web 91.
-A' (see FIG. 2) Up to the boundary layer between the cleaning liquid 93 and the suspension liquid 89 along Q is replaced (expelled).

The displaced suspension liquid 89 drains from the barrel surface 13.

There, during the passage between the washing zone 27 and the compression zone 29, only the layers closest to the body surface 13 of the fibrous web 91 (i.e. only the layers below the line AA') contain the suspension liquid 89. However, the rest of the fibrous web contains only the cleaning liquid 93.

At the press engagement 55 forming the compression zone 29, the fibrous web 91 is preferably compressed to a density of 30 to 70, and further contains only the cleaning liquid 93 at the beginning of the closure zone 29.

The web is temporarily compressed to a thickness that is less than or equal to the thickness of the web portion.

As long as the body surface of the press roll 47 is liquid-impermeable, all the dewatering that occurs in the press mesh 55 passes through the body surface 13 of the drum 11.

Therefore, the suspension liquid 8 remaining in the fibrous web 91
9 are all first drained through the body surface 13 of the drum 11, and then some of the cleaning liquid 93 is drained through the body surface 13.

There, only at the press engagement 55 is a quantity of cleaning liquid drained or squeezed through the barrel surface 13 and mixed with the suspension liquid 89 inside the drum 11 .

After the fibrous web has passed through the press mesh 55 of the compression zone 29, it is free to expand in the treatment zone 31;
At the same time, a certain amount of impregnating liquid 95 per unit time is forced into the fibrous web 91 through the perforations in the pressure cuff I and casing 19.

Due to the fact that when the fibrous web expands it tends to refill the voids created by the expansion, the penetration of the impregnating liquid into the fibrous web takes place very quickly and effectively.

In the downstream part of the impregnating zone, measured in the direction of rotation of drum 11, impregnating liquid 95 replaces the cleaning liquid remaining in the fibrous web.

The cleaning fluid consists mostly of cleaning fluid that has rewetted the fibrous web after the press engagement 55.

Line BB' in the fibrous web 91 (see Figure 2)
Along Q, a boundary layer forms between the impregnating liquid and the cleaning liquid.

The displaced suspended 'rL liquid drains through the barrel surface 13.

This displacement process is similar to the cleaning liquid/suspension liquid displacement process described above and culminates in press engagement 57 where the cleaning liquid 93 is squeezed and a portion of the impregnating liquid cleans the fibrous web. and permeates into the drum 11.

Due to the strong compression of the fibrous web in the press engagement 55, this fibrous web acts as a seal between the cleaning zone 27 and the processing zone 31 (in the compression zone 29 located here).

This prevents processing liquid from flowing into the cleaning zone 27 from the processing zone 31 .

In order to realize the desired displacement process, i.e., to displace the cleaning liquid under line A-A' and to displace the impregnating liquid under line BB' (Fig. 2), the following variable factors, i.e., press engagement: The linear pressure of the cleaning section 57, the rotational speed of the drum 11, the amount of the cleaning liquid flow, and the amount of the impregnating liquid flow 95 are linked by a control device.

The gap thickness of the press mesh 57 and the supply of the fibrous suspension are known per se and are kept substantially constant using devices not shown in the figures.

Pressure gage device 59 generates a signal indicative of the actual linear pressure value during continuous operation, and this signal is communicated to controller 75 where this value is determined as a predetermined desired value (the "setpoint"). be compared.

If there is a difference between the actual value and the set value, the controller 75 generates a correction signal to the speed controller 17G of the drum 11 in such a way that as the linear pressure decreases, the rotational speed of the drum 11 decreases.

The controller 75 also controls the drum rotational speed set point (and accordingly signals the servo control valves 41'j6 and 45 to control the flow of cleaning liquid 93 to the cleaning liquid chamber 35 and the flow of impregnating liquid 95 to the chamber 37, respectively). Fix it.

After the fibrous web 91 has passed through the press engagement 57 of the press zone 33, it is removed from the body surface 13 of the drum 11 by means of a doctor blade 67 and guided into the removal and feeding device 1.

The fibrous web is free to expand within the device U and, as it expands, tends to refill the voids created in the web.

A gaseous medium (preferably water vapor) is supplied to the device 1 under pressure through the supply conduit 71.

The voids mentioned above are refilled with this gaseous medium, thereby preventing the fibrous web from absorbing air.

The fibrous web is broken up by a crushing and feeding screw 65 and conveyed under pressure from this device to the next step in the manufacturing process.

The embodiment of the invention shown in FIG. 3 is much the same as and operates similarly to the embodiment shown in FIGS.
7, and by this step the casing 1
The radial distance between 9 and the body surface 13 of the drum 11 gradually decreases, forming a press engagement portion 99.

After this press engagement 99, the radial distance increases sharply and the fibrous web is substantially free to expand.

The treatment liquid of the present invention may consist of a liquid effective for bleaching cellulose fibrous pulp.

In the present invention, in addition to conventional bleaching agents such as chlorine, chlorine dioxide, hydrogen peroxide, oxygen, etc., reactive agents such as caustic nose, ammonium hydroxide, magnesium carbonate, alkali metal borates, etc. and catalytic agents, and combinations of these agents are also contemplated.

[Brief explanation of the drawing]

FIG. 1 shows a schematic side view of an embodiment of the device and the method of the invention. FIG. 2 is a side view showing the progress of cleaning liquid replacement and subsequent impregnation. FIG. 3 schematically shows another shape of the upper part of the device shown in FIG.

Claims (1)

[Scope of Claims] 1. A liquid-permeable screen element is sequentially moved in an endless passage along a web-forming zone, a washing zone, a processing zone, and a pressing zone to form a fibrous suspension of cellulosic material. zone and dewatering the fibrous suspension onto the screen element to form a fibrous web, during subsequent compaction of the fibrous web formed in the web forming zone and deposited on the screen element. The fibrous material (fibrous pulp) is washed in a washing zone, the fibrous material web (fibrous pulp or ) continuous processing method Q, in which a compression zone located between the cleaning zone and the treatment zone has strong compression that substantially prevents the passage of the treatment liquid from the treatment zone to the cleaning zone. applying to the fibrous web and expanding the fibrous web in the treatment zone;
and the above-mentioned fibrous material (fibrous pulp) characterized in that a processing liquid is supplied to the expanded fibrous material web in the processing zone.
Continuous processing method. 2. The fibrous web is compressed in the press zone in such a way that cleaning liquid that may remain in the fibrous web is replaced by a treatment liquid.
the method of. 3 Supplying the processing liquid in the processing zone so as to displace the cleaning liquid remaining in the fibrous surface web to a distance from the screen element that is at least as large as the minimum distance of the press zone above the screen element. Claim 1 characterized in that it is quantitatively adjusted.
the method of. 4 Claims 1 and 2 above, characterized in that the treatment liquid can be applied to bleaching in the bleaching process of fibrous pulp.
Or method 3. 5. The method according to claim 1, 2 or 3, wherein the treatment liquid consists essentially of water vapor. 6. The method according to claim 1, 2 or 3, wherein the treatment liquid consists essentially of water. 7. The above method, characterized in that the fibrous web is separated from the screen element after the press zone, and the separated fibrous web is sent to the next processing step while preventing air intake in the fibrous web. Claims 1 and 2
．． Method 3 or 4. 8 Body surface 13 made of liquid permeable screen element
a rotating drum 11 having: an internal liquid disposal device 85 and a drive and speed control device 17; a casing 19 covering at least a substantial part of the drum 11, the casing 19 having a a web-forming zone 25 with an inlet device 23 for the fibrous suspension 87 successively along the direction of rotation of the drum 11 and at least one web-forming zone 25 located outside the casing 19;
a cleaning zone 27 communicating through perforations in the casing 19 with two cleaning liquid chambers 35 , at least one chamber 370 located outside the casing 19 and a processing zone 31 communicating through perforations in the casing 19 ; defines the press zone 33 that defines the body surface 13 of the drum 11 and the press meshing portion 57, the compression zone 29 is located between the cleaning zone 27 and the processing zone 31, and the compression zone is Device 47°97 and drum 1
1, and the radial distance between the drum 11 and the casing 19 in the processing zone 31 is the same as that between the drum 11 in the compression zone 29 and the pressing device 47.97. Apparatus for carrying out the method according to claim 1 for the continuous treatment of fibrous material (fibrous pulp), characterized in that the radial minimum distance is more than 100 cm. 9. The device according to claim 8, characterized in that the press device comprises a press roll 47. 10 The press device presses the casing 1 toward the drum 11.
9. Device according to claim 8, characterized in that it consists of a step device (97) converging inside the device (97). 11 Quantitative supply of cleaning liquid 93 to the cleaning zone 27 characterized in that a substantially gas-tight removal and supply device 61 of the fibrous web 91 is located after the press rolls 49 of the press zone 33 {The device according to claim 8, characterized by a device for controlling this. 13. The apparatus according to claim 8, characterized by a device for quantitatively controlling the supply of the processing liquid 95 to the processing zone 31. 14 A pressure gauge device 59 is arranged to sense the linear pressure of the press engagement portion 57 between the press roll 49 and the drum 11, and a pressure gauge device 59 is arranged to control the rotational speed of the drum 11 in response to the linear pressure. 14. The device according to claim 12 or 13, characterized in that the device 6 for quantitative control includes a controller 75.