JPS60146090A - Production of mechanical pulp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing mechanical valves. In particular, the present invention relates to a method of increasing the whiteness and improving the effluent and strength properties of mechanical valves.

The production of mechanical pulping is gaining increasing interest because higher yields can be obtained from a given amount of raw material using mechanical pulping methods compared to chemical pulping methods. Mechanical pulping is generally performed using thermo-mechanical valves (TMP>, chemical-mechanical valves (CMP>) and chemical pre-mechanical valves (CT).
MP). Although mechanical valves can be useful for many purposes, they often cannot be made of sufficient whiteness for many intended end uses, and their whiteness deteriorates over time. Furthermore, the mechanical refining process utilized as a key component of mechanical pulping often results in the degradation of fibers with desirable properties such that the final valves produced have relatively poor wastewater properties, and relatively high
Has weak strength.

According to the invention, the mechanical pulp is TMI], CMP,
A method is provided for enhancing the whiteness, drainage and strength properties of either CTMP or CTMP.

According to aspect of the present invention, TMP, CMP or CT
MP is manufactured by the following steps sequentially: (1)
iii) Impregnating the crushed fibrous cellulosic material with a chemical or thermal treatment fluid.

(ii) Washing the impregnated material. Cleaning is preferably accomplished by delivering a cleaning solution containing a root agent and a surfactant countercurrent to the flow of the lube, and removes any residual cooking chemicals, metals, colored objects, and resins, leaving behind the white color of the bulb. It is effective in removing many substances that can have adverse effects at the same time. (iii) The washed material is mechanically refined to produce a mechanical pulp preferably having a consistency of about 6-15%. and (iv) further processing the mechanical pulp including bleaching with hydrosulfite and/or peroxide to obtain desired properties.

According to another aspect of the invention, countercurrent flow of the sulfite drug and the crushed fibrous cellulosic material is achieved to
CMP or CTMP valves are manufactured by effectively impregnating CMP or CTMP valves. The material is subsequently steamed and then refined and further processed as described above. Countercurrent impregnation is a chip,
or other materials, resulting in a more uniform removal of impurities from the depth in a manner that provides highly effective penetration of the sulfite solution and ultimately improves valve properties and reduces bleaching costs. .

According to yet another aspect of the invention, mechanical pulp is produced by a series of refining processes. The dip, or similar ground cellulosic fibrous material, is pretreated and then passed through a first pressure refiner. From the first refiner, the mechanical pulp reaches a screen where the portion of the pulp that requires further refinement is selected and sent to a first stream, while pulp fibers that already have the desired properties are sent to a second stream. The first stream passes to a second pressure refiner having an effluent, and the second stream passes directly to the second refiner effluent.

The mechanical pulp according to the invention has increased strength and drainage and can be bleached to higher brightness levels (e.g. as high as 5 appa ti) than was possible in the prior art and It can be easily bleached to any given brightness level.

It is the main object of the present invention to provide a mechanical pulp with enhanced playable properties. This and other objects of the invention will become apparent from a review of the detailed description of the invention and from a reading of the attached 1JI patent claims.

DESCRIPTION OF THE INVENTION REFERRED TO Δ・14-■ In accordance with the invention, mechanical pulp J, eel mechanical pulp, especially CM P XT M , R and CT
MP is manufactured. FIG. 1 shows a CMI according to the present invention.
), while Figures 2 and 3 show the manufacturing method of CTMP and TMP, respectively, with the steps in each being identical to those in Figure 1 but not illustrated.

Referring to FIG. 1, the hardwood or softwood depth or other ground cellulosic fibrous material is first steam treated at point 11. They are then countercurrently impregnated with a sulfite chemical (eg, putrium sulfite) at 12 locations, the countercurrent action properly distributing the chemical into the chip.

Although the chemicals facilitate the removal of water-soluble substances and some of the lignin and polysaccharides, most of the lignin and polysaccharides remain in the material. After impregnation, the depth is subjected to countercurrent cleaning in 13 steps.

The cleaning solution preferably contains a chelating agent and EDPA and D
Contains surfactants such as PTA. Cleaning accomplishes the removal of residual cooking chemicals, metals, colored objects, and resins. 12
．． Counter-current impregnation and counter-current washing at 13 locations combine to improve pulp properties, lower subsequent bleaching costs, and remove impurities very uniformly in such a way that the valve maximizes bleaching brightness. do.

The cleaned depth is transferred from location 13 to the first pressure viscous stage 14.
, where a mechanical refiner acts on the chips to form mechanical pulp. At this stage, the valve typically reaches a consistency of 5-16%, and at this consistency the valve passes through point 15 where it is divided into the first and second streams 16.17. The first stream contains pulp components that require further refining, while the second stream 17 contains pulp portions with fibers of desirable properties that do not require further refining. The first stream 16 passes through the second pressure purification stage 18
while the second stream 17 passes directly to the discharge line 19 from the second purification stage 18. In this way the fibers with the desired properties are not further degraded and in this way the drainage properties and strength of the valve are improved.

The valve in the IJI output line 19 has a consistency of 6-15% and is further processed by any desired method to produce a CMP with the required properties. Typically this will include a wash station 20 and a bleach station 21. During bleaching, sulfite and/or peroxide are added to the valve and the resulting final acid will be the bleached CMP.

For the CTMP process illustrated in FIG.
The only fundamental difference between the CMP process described in the figure is the provision of a boiling stage 23 between the impregnation stage 12 and the cleaning stage 13. The sulfite steaming is carried out at suitable temperature and concentration conditions to provide the necessary effect on the depth to facilitate its subsequent purification. CTMPs have slightly lower yields than other mechanical valves such as TMPs, but typically have high strength and are particularly suitable for high density hard water pulping.

Figure 3 shows a typical process for TMP. In this embodiment no impregnation step 12 is provided. Typically,
The chip may be steamed for a longer time than in the embodiments of Figures 1 and 2, and may additionally be provided with a container for applying heat in the form of steam or hot liquid. TM after passing from 13 to 21
P occurs.

FIG. 4 shows the J used to produce CMP according to the present invention.
A typical device that can be used is briefly described.

The chips are fed into a conventional steam-heated chip bin 25 and subsequently metered into the inlet to the vertical container 27. Countercurrent impregnation and countercurrent cleaning of the chips takes place in vessel 27 . Sodium sulfite, a suitable chemical for the production of CMP, is fed from source 28 through heat exchanger 29 to vessel 27 and charged at the appropriate point 3o. The chemicals flow upwardly in the container 27 countercurrently with the downward flow of the chips.

Pump 31 continuously draws chemical from container 27 through the sieve and reintroduces the chemical to pass through the depth adjacent inlet 26 therein.

At the bottom of vessel 27 countercurrent washing occurs. Fresh wash solution and chelating agent and surfactant are introduced into line 32 and passed countercurrently to the chip, with the wash solution flowing into container 2.
7 and recirculated by pump 33. The metals, colored objects and resins displaced by the impregnating and washing steps ultimately find their way to a device 34 which accomplishes their removal and discharge.

The washed chips pass through line 35 to a conventional drain 36
The dispensed liquid is then returned to the container 27 under the action of the pump 37. The tip is the first pressure refi-3
8 and subjected to mechanical action to produce mechanical pulp. Practicing this method, the valve will typically be about 6-
It will have a consistency of 15%. After pressure reduction or dilution, the bulb is then screened through sieve 39. Sieve 39
The valve part is separated into a first stream 4o which requires further purification, while fibers which already have the required properties are separated into a second stream. The first stream 40 may pass through a cyclo/ron 42 and then to a second pressure refiner 43 while the second stream 41 passes directly to the first no.1 output 44 from the second refiner 43.

After refining, the mechanical pulp can be passed through a pressurized blow tank 45 to recover heat and subsequently diluted again ii-,
J', it is pumped by pump 46 to another sieving mechanism 47 which is essentially identical to sieve 39.

The rejects from the sieve 47 are sent to a reject box 48 and then passed through a sedimentation separator 49 to a reject refiner 50.
Finally, via line 51, it returns to sieve 47, person 1. The receipt from sieve 47 is sent to pump 52 to J-C creep 53 and finally washed in pressure diffuser 54 without further treatment. For example, the valve is a high temperature storage tank 5
5 and then pumped by a pump 56 for degassing;
Introducing the sulfite bleaching chemical there through mixer 57 and then subsequent retention in holding vessel 58 can produce enhanced brightness and/or drainage and strength properties. In this drawing, components having the same functions as those illustrated in FIG. 4 are indicated by simply placing [1-1] in front of the same reference numerals.

The dip was fed into a conventional dip bin 125 and then steamed in a steaming vessel 60.

The chips are conveyed along with the liquid into chute 126 and high pressure feeder 61 feeds them to the top of vessel 62. Sand A3 and other undesirable components are part 63.6
4 to separate and remove.

A straight mixer 62 impregnates the chips, holds them for steaming, and washes them. The container 62 is impregnated with
A conventional continuous digester for producing chemical pulp with a cooking and washing zone is structurally similar. !
II! The acid cooking chemicals are added at any desired point, such as line 65, and heat exchanger 66 heats the chemicals to the desired temperature.

Countercurrent impregnation occurs in vessel 62, the chips remain in the cooking zone for a predetermined time, and countercurrent washing occurs at the bottom of vessel 62, with washing liquid added through inlet 67.

The chip slurry discharged from the bottom of the container 62 is drained into the drain 1.
36 and pressure refiner 138 . A pressurized blow tank 145 is provided after the first refiner 138,
The pulp, preferably having a consistency of about 6-15%, is then sent by pump 68 to sieve 139 and first stream 1
The valve material in 40 passes to a second pressure refiner 143 and the pulp fibers in a second stream 141 are sent directly to the first output 144 from the second refiner. The pulp is then introduced into a decker 69,
It is pumped by pump 70 to the top of pressure diffuser 154 , washed therein, and discharged from diffuser 154 into countercurrent vortex 71 . The peroxide bleaching chemical is added to line 72 and introduced into the valve in diffuser 154, while column 71
The pulp bleaching chemicals are held for a predetermined period of time before being discharged to decker 73. From there it is passed to a high density polishing reservoir 155 and by pump 156 to a mixer 157 where the hydrosilphite bleaching chemicals are introduced. Final CT M P after being held in the counterflow vortex 158
occurs.

The apparatus shown in FIG. 6 can also be used to produce CTMP and is intended for the purification of valves over a significantly wider range (eg, about 5-50%). In this drawing, components having the same functions as the components illustrated in FIG. 4 are indicated by the same reference numerals with a ``2'' placed inside.

After leaving the container 227, the crushed fibrous cellulose H
The stone suspension can be dewatered using a conventional dewatering device 80 (such as a plug screw feeder or screw--pressurizer) in line 235. The ilQ water device 80 can be used in place of or in addition to the conventional iJl water dispenser 236. The suspension from the dehydrator 80 may have a concentration as high as 50% before it is fed to the first refrigeration booth 238. Device 80 may or may not be pressurized depending on the other devices used.

The valve discharged from the first reno eye 1--238 is diluted using a conventional diluter 81 before reaching the first sieve 239, if the high-depth platform is used. Line 24 from sieve 239
The January output to 0 is compressed to 1", preferably using a conventional compressor 82, before entering the recycler 242, and the refiner 243 also compresses high a degree pulp (e.g., 16-
50%). The II output from No. 5-243 in line 244 is then diluted again using diluter 83 where it passes to blow tank 245 to have substantially the same consistency as the pulp in line 241.

The practice of the present invention provides more b''J than prior art mechanical valves manufactured utilizing similar processing chemicals,
,' It is possible to produce a mechanical pulp which can be whitened to a high standard of whiteness in terms of Y'i, and the valve according to the invention has different processing conditions. It offers improved strength and wastewater properties compared to conventional mechanical pulp produced under 1.

The present invention herein represents what is presently considered to be the most practical and preferred embodiment thereof, and although the present invention has been described in detail, it is contemplated that many improvements may be made within the scope of the invention. It will be apparent to those skilled in the art that the appended claims are to be given the broadest scope so that their scope includes all equivalent methods and products.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a typical apparatus for producing chemical-mechanical pulp according to the method of the present invention; FIG. 2 is a block diagram of a typical apparatus for producing chemical-thermo-mechanical pulp according to the present invention. FIG. 3 is a block diagram of a typical apparatus for producing thermomechanical pulp according to the present invention; FIG. 4 is a schematic diagram of a typical form of a typical apparatus useful in the practice of the present invention. and Fig. 6 shows a wide range of 111 KU11 < e.g.
FIG. 4 is a diagram similar to that of FIG. 4 for pulp processing in FIG. Numbers used in place of explanatory text for main parts in the drawings represent the following. In addition, "2" is added in FIG. 4 and FIG. 6. 25... Chip bin 26... Container population 27...
Container 28...Medical supply source 29...Heat exchanger 30...Medical introduction point 31...
Hop 32... Line 33... Pump 34... Discharge device 35... Line 36... Drainer 37... Pump 38... Refiner 39...
tiA 40...First flow 41...Second flow 42
...Cyclone 43...Refiner 44...
Discharge 45... Blow tank 46... Pump 47...
- Mechanism for sieving 48... 4 boxes for inclusions... Sedimentation separator 50... Refiner 51... Line 5
2...Pump 53...Cleaner 54...1 Juryoku 1 Hiro 1 Attack 5
5...Storage tank 56...Pump 57...Mixer 58...Holding container 60...Steam processing container 61...Supplier 62...Upright container
63...Separator 64...Separator 65...Line 66-...Heat exchanger 67...Line 68...Pump 69...Dinker 70...Pump 71...
・Tower 72...Line 73...Decker 80...Dehydration device 81...Dilution device 82...Compression 83...
- Dilution device 125...Dip pin 126...Chute 136...Water vessel 138...Refiner 139...Sieve 140...First flow 141...Second flow 143...Refiner 144...discharge
145... Blow tank 154... Pressure diffuser 1
55...Storage tank 156...Pump 157...Mixer 158...Backflow column 227...Container 235...
・Line 236...1 no 1 water container 238...Refiner 239...Sieve 240...Line 241・
・・Line 242・・Ikron 243・・Refiner 244・・Line 245・・Blow tank agent Akira Asamura

Claims (10)

[Claims] (1) (a) impregnating the ground fibrous cellulosic material with a chemical and/or thermal treatment fluid; (1]) washing the ground fibrous cellulosic material; (A) refining the dark blue cellulosic material to make mechanical valves; and (C) further processing the mechanical pulp, including bleaching, to achieve desired properties by TMP, CMP or CT.
A method for producing MP, characterized in that the impregnated pulverized fibrous cellulosic material of (dll) is washed between steps (a) and (b). (2) carrying out step (a) by passing the treatment fluid countercurrently to the flow of the ground fibrous cellulosic material, and passing the cleaning liquid countercurrently to the flow of the ground fibrous cellulosic material; J: The process of passing through (d
) The method according to claim 1, further comprising carrying out the following. (3) (i) passing the washed fibrous cellulosic pulverized material through a first sweat refiner; (ii) sieving the discharge from the first refiner to pass the fibrous material 1 through the first and second refiner; (iii) passing the first stream through a second pressure refiner having an output; and (iv
) by directing the second stream to the discharge from the second rift 7 huipoo. A method according to claim (1), further characterized in carrying out (b). (4) The mechanical valve according to claim 1, further characterized in that the resulting mechanical valve after steps (a), (d) and (b) has a consistency of about 6-15%. Method. (5) Crushed fibrous cellulose monthly flow and countercurrent heat! II! through the sulfate liquid and vJ') crushed I
4. The method of claim 4, further characterized in that step (a) is carried out by heating the fibrous cellulosic material in steam prior to impregnation. (6) further characterized in that step (d) is carried out by utilizing a cleaning liquid containing a cleaning agent and a surfactant to accomplish the removal of metals, colored objects, resins, and the like; A method according to claim No. (1). (7) Sequentially: (a) Hot sulfite chemicals 1! i
[Navy Cell 1] - impregnating the pulverized fibrous cellulosic material with a sulfite chemical by sending it into contact with the fibrous cellulosic material: (b) refining the fibrous cellulosic material to produce a mechanical valve; and (C) further processing the mechanical valve to achieve desired properties, including: A process characterized in that (a) is carried out by passing in a first flow direction and passing the liiiItrite chemical in a second flow direction countercurrent to the first direction. (8) (i) passing the washed fibrous cellulosic crushed material through a first pressure refiner; (ii) screening the effluent from the first refiner to separating; (iii) passing the first stream through a second pressure refiner having an effluent; and (
1v) A method according to claim 7, further characterized in that step (b) is carried out by passing the second stream directly through the effluent from the second refiner. (9) (a) pretreating the pulverized fibrous cellulosic material; (b) refining the pulverized fibrous cellulosic material I to produce mechanical pulp; and (C) imparting desired properties. In a method of producing mechanical pulp comprising the step of further processing the mechanical pulp to achieve; (1)
passing the washed fibrous cellulosic crushed material through a first pressure refiner; (ii) screening the effluent from the first refiner to separate the fibrous material into first and second streams; (iii) Step (1) by passing the first stream through a second pressure refiner having an effluent: and passing the second stream directly through the effluent from the second refiner.
A method characterized by carrying out b). (10) Treating the ground cellulosic fibrous material by countercurrent flow of a sulfite liquid: achieving countercurrent cleaning of the sulfite-treated material, the cleaning liquid comprising a chelating agent and a surfactant: the washed material to produce mechanical valves: and mechanical pulp hydrosulfide and/or
Or a bleached mechanical pulp with increased whiteness, characterized in that the bleached mechanical pulp is produced by peroxide bleaching and manufacturing processes.