JPH01502206A - Method for producing cellulose pulp and/or delignification method for recycled fibers - 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] Method for producing cellulose pulp and/or delignification method for recycled fibers field of invention The present invention uses a chemical-mechanical composite method to convert plant and wood fibers into paper, board, textiles, etc. Digested into cellulose pulp used as raw material for fiberboard and fiber-containing products This invention relates to a method for continuously producing Rudame cellulose pulp. The present invention also provides recycled fibers. Very suitable for fiber deinking, delignification and optionally bleaching, fiber separation This also includes cellulose pulp, which has been manufactured using the known sulfite method or the known sulfur method for decades. It has been produced by the acid salt method. Today, both methods are too difficult to implement economically. requires a large-scale plant to produce cellulose using the sulfite method or sulfate method. It is very expensive to build a new plant for this purpose. Despite that Recently, several new cellulose mills have been built during development, and their It has suffered huge financial losses since its launch.

Several similar mills are currently being built in developing countries; It is certain that in a few years these mills will incur great economic losses. I can tell you in advance.

The reason is that today's usual technology for the continuous production of pulp This is because prices have become too high compared to what the loin market could offer. this The situation is critical for developing countries that need to build their own cellulose or paper industries. is particularly unsatisfactory and untenable.

If a new continuous mill for cellulose production can operate profitably, the investment Is it from the perspective of substantially reducing capital costs per year and annual production capacity (tons)? A complete revision and update of the cellulose process must be carried out. of pulp Today's technology for continuous manufacturing is mainly due to the steadily increasing cost of the sulfite process in recent years. Based on the sulfate method, which has experienced a wide range of applications. This fact explains, for example, that the sulfuric acid method In contrast, the sulfate process is used for most of the textile raw materials of interest. moreover, Today's WLa salt process involves the recovery of cooking chemicals and the recovery of organic compounds in so-called "black liquor." Things burn as you wish. Therefore, in recent years, the sulfate method has been It is considered to be a method of producing cellulose that is not very harmful to the environment. It's here.

However, this method still has a number of serious disadvantages, which are discussed below. state

1. The sulfate method has developed into an extremely capital-intensive method, resulting in so-called "economies of scale." As a result, extremely high production capacity is required. Such large-scale plants Accordingly, strong demands are placed on transportation capacity and basic facilities, but approximately 200,000 to 30,000 Plants with a capacity of I don't have much profit.

2. In the sulfate method, sulfur compounds are used, which cause odor and air pollution. Responsible. Furthermore, when it comes to bleaching, chlorine-containing compounds are commonly used and are toxic. Produces harmful exudates into the environment.

3. Sulfate mills are complex, consisting of many very different process and mechanical elements. system, each of which is divided into separate sections for steaming, sorting, washing and bleaching. Each section has separate heat, water, chemical and drainage systems.

Thus, today's sulfate mills feed the top at a high consistency where the fibers cannot be pumped. The fibers are then passed down the digester according to the "free fall" principle. The fibers can then be pumped at the bottom of the digester or A vertical high-pressure digester that dilutes to a blowable J consistency. and is usually characterized.

4. The sulfate process is relatively slow, which reduces the capacity and ground of the process. The demand for hard disk space is substantial. This is because the fiber pulp is being processed during its processing. more slowly than if the fiber pulp were further moved and disturbed (the “washer effect”) Relatively few movements are made that would cause the reaction to proceed again.

5. The temperature and pressure used during pulp cooking are usually controlled by the heat source used until the cooking process. determined by the fixed relationship between the pressure and temperature of saturated steam traditionally used as be done.

6. A tall vertical diffuser, usually connected to a complex heat recovery system, protects the pulp after cooking. Used for "blow".

7. During the process with internal transportation, sorting, washing and bleaching, many different parts Repeated dilution and concentration of pulp with respect to pulp consistency is high, large and highly This is done with large and complex equipment often found in large inventories in expensive factory buildings. It will be done.

8. Large amounts of water and chemical solutions require vast areas and are expensive to collect and collect. and/or treated in a purification plant.

9. Pulp mills shall indicate all possible causes of defects and carry out corresponding inspections; Very difficult to maintain and require comprehensive and expensive inventory of numerous spare parts. It consists of a number of different machines, operations and functions.

Purpose of invention The object of the present invention is to provide a method for producing cellulose pulp and/or optionally bleaching it. , or alternative methods of delignifying recycled fibers, including deinking or other types of cleaning. The method is the most interesting technology and the most closely related to the method of the present invention. The above-mentioned exception J regarding the sulfate method, which is typical of the related technology: there are no substantial drawbacks. . This method requires fewer processing operations compared to today's conventional cellulose pulp production methods. processes that reduce capital, site, inspection and maintenance requirements, including the simplification of Consists of mechanical equipment. This method has the so-called "cleaning" effect as well as chemical solutions and thermal Extensive recycling and reuse of energy is obtained, and the method is currently not commonly used. progresses from raw material to finished cellulose pulp more rapidly than conventional methods. Chemical liquid and Extensive recirculation and reuse of heat energy and heat energy is an optimal process for this method. Guarantees savings and further reduces runoff to natural water sources by reducing water consumption. Do a little. Regarding the equipment and processing steps for carrying out the method, they essentially include: Through simple internal modifications, for all interesting textile raw material processing combinations. It is also an object of the invention that it can be divided into modules as possible. Sara Such a module would be installed within a standard shipping container frame. Simpler and cheaper assembly, transportation, start-up, and location-to-place It is also an object of the invention that the movement of the plant to

Summary of the invention The present invention is characterized in that the fiber raw material is introduced into the cooking liquor, in which the fiber raw material is introduced into the cooking liquor, in which the acid and optionally small amounts of other adjuvants such as anthraquinones. Cooking and delignification at high temperature and pressure using alkaline cooking chemicals; Steaming in the form of black liquor, where the cooking liquor is stored or transported for recovery of the chemical solution. Decomposition is the paper, cardboard, fiberboard and other materials removed from the delignification process. to obtain a pulp suitable as raw material for products containing plant and/or wood fibres. plant and wood fibers are cooked or delignified and optionally chemically or mechanically A method of pre-deinking fibers from mechanical pulp, optionally followed by bleaching, comprising: The pulp stock in the form of a pumpable slurry is processed through cooking, delignification and the desired Slurry 8 is added during deinking and optionally subsequent bleaching. A pulp pump is used at the same time as a mixing assembly for liquids and chemicals. t; conveyed through a continuous pressurized system, repeatedly while the pulp is conveyed through the tubing system. The dehydration process is repeated and the liquid is pushed out, and each dehydration process, apart from the last dehydration process, The liquid extruded from the process and the dewatering steps downstream of the process are and/or diluted by liquid recirculated from downstream pumping stages of the process. and one or more pumping stages while the pulp is conveyed through the tubing system. The pressure is increased stepwise at Diluted with clean water and/or bleaching solution supplied with After the final dewatering, which takes place in the water system, the pulp is washed and, if desired, subjected to continuous pressure. It is characterized by being bleached while performing cold or hot blowing in a system or non-pressurized state. Regarding how to.

Brief description of the drawing Figure 1 shows a gradual increase in pressure from the first dehydration step to the fourth dehydration step. 1 is a flow sheet of a specific example of the method of the present invention, which includes four dehydration steps.

Figure 2 is from left to right in the figure, i.e. from the beginning to the end of the cooking process. FIG. 2 is a diagram showing the relative pressure increase according to the flow sheet of FIG. 1;

Figure 3 shows the 70-seat shown in Figure 1 for supply and recirculation volumes of liquid and chemical solutions. This is a Sankey diagram of the process by

Figures 4 to 24 describe the process and will be discussed in more detail below. .

Detailed method and drawings An embodiment of the method is further disclosed with reference to the drawings.

1 and 2, raw material 1 and water 2 are supplied to pulper 3, and raw material and water 2 are supplied to pulper 3. The pulper and clean water are transferred from the pulper to the pump P by the pump P and the cleaning device 4. The slurry having a consistency of approximately 4% is then pressurized and the pressure level It increases to p2. As described further below, until reaching a consistency of about 10 to 30% The slurry is extruded through a dewatering device 5 which dehydrates the slurry. dehydrated The pulp is further transported to this pulp in the tube between the dehydrator and pump P3. Using recirculated cooking liquor from the pressure build-up stage and/or pressure dewatering stage of the process. It is diluted. Furthermore, in the tube section between the dehydrator and the pump P, A fresh solution of chemical and/or even heat 6 can then be supplied to the slurry. Escape The liquid 7 pushed out by the water device 5 is mainly transferred to the heat exchanger 8, where it is pushed out. The collected liquid (effluent or waste water) is transferred to the supplied clean water or bleaching plan via heat exchange. The waste water from the A part of the liquid pushed out from the dehydrator 5 is It can be fed to the pulper 3 to form a raw slurry having a consistency of about 4%. vinegar Before the rally enters the pump P, and then the dehydrator 5, a subsequent pressure increase stage of the cooking chemical recirculated from the cooking tube immediately after the pump P, which causes the Spent solution 12 is supplied. The pulp is extracted from the pumping stage ps (Fig. 2). is transferred to a new pumping stage p4, and the two pumping stages p, and p, While recirculating the cooking chemical 13 into the slurry, the pressure applied to the slurry is further increased. increases to The tube section between the pumping stage p and the pumping stage p4 The spent cooking liquor 14 is then recycled to a pumping system that increases the pressure. removed from the digester tube immediately after stage p. Then the pulp consistency is still approx. 4% slurry is transferred from pump P to the next pressure increasing pumping stage p. The next dewatering step is to dewater the slurry again until the pulp consistency is about 10~30%. The spent recycled to the pressure pump P, where the slurry is further processed through the equipment The slurry is transferred from this pumping stage while again feeding the boiling solution 15. be done.

The recycled liquid 17 forms a pulp slurry with a pulp i degree of approximately 4%. Therefore, the pulp is transferred from the dewatering device 16 again while being diluted to the next pressure increasing pump. P7 and from this pump enters the next dewatering unit 18 where the slurry is Dehydrated again to a mass consistency of about 10-30%. Pulp is the first Liquid from a bleaching plant transferred to it after being removed from the digestion section shown in Figure 1 19. Addition of clean water or optionally waste water 9 results in a pulp consistency of approximately 4%. While diluting the slurry to It is transferred to P. Finally, as the pulp exits the pressurized tubing system, it is 00°C or less, i.e. does not expand, or more specifically, it Low temperature, such as being subjected to "cold blow" when exiting the tube system This liquid 9 is supplied before the pressure increase pump P, so that the pulp can be cooled to is preferably relatively cold. The slurry is pumped from the pressure increase pump P, shown last. It reaches the dewatering unit where it is dewatered again to a pulp consistency of 10-30%. 10～ The dewatered slurry with a pulp consistency of 30% is then passed through a closed coop at the end of the tube. It is removed from the system through a closure cone 21. this cone The lid is of known construction, creating a back pressure controlled by an air-filled bellows. , a controllable pressure is applied against the base of the conical sealing means.

The amount of pressurized water injected into the system is controlled by control pulp R2, and the waste liquid from the Controlled by control valve R1. For control purposes, the pulps are interconnected so that The volume of liquid forced into the system corresponds to the volume of waste liquid.

The flow sheet in Figure 1 is used to improve the quality of recycled fibers and to improve the quality of unbleached cellulose from annual plants. Indicates the production of As mentioned above, the main consistency during transport through the tubing system is approximately 4%. and the consistency after dehydration is about lθ~30%. In the flow sheet of Figure 1 , three reaction modules (M1%M, and M3) for delignification are shown; followed by two washing steps (pt and pm). The bleaching section is connected to the system shown in Figure 1. As mentioned above, it can be connected to the quality improvement section and the digestion section for bleaching as well. method may be used, but obviously certain chemicals must be used in a manner sufficient to obtain the desired bleaching. Use in appropriate amounts.

This method can be applied to all kinds of vegetable fibers such as bagasse, Kena 7, rice straw, rubber tree, Waste from palm oil production and bamboo and hardwood (hardwood) and softwood (coniferous) ) used for Similarly, the method includes delignification and optional bleaching of recycled fibers. fully suitable for. Furthermore, when using printed recycled fibers, depending on the system configuration, The raw material can be deinked without the use of extra mechanical addition equipment. This method uses a mechanical pulse pulp (MP) to thermomechanical pulp (TMP) and chemical-thermomechanical pulp (C-TMP) ) to pure chemical pulp (CP) enables a wide range of reactions including the production of

As mentioned above, the flow sheet shown in Figure 1 Suitable for cooking or steaming annual plants or improving the quality of recycled fibers. sawdust , for cooking or cooking hardwood or softwood, the method provides mechanical processing within the refiner. must be provided.

A pressure screen can be used after the refiner, which separates the crude from the receiving material. The rough chips are separated and the treated coarse chip fraction is treated with new chemicals and machined. Return for mechanical processing. This includes many other fibers that can be applied to any fiber of interest. Can be used for programs.

Apparatus for carrying out the method and steps of the method as stated for the purpose of the invention However, it is also an object of the present invention that it serves to divide the system into modules in nature. Figure 4 In , the main principles of an embodiment of the method are presented somewhat briefly. According to figure 4 For example, after slurrying 3, close t shown at 22; impregnation and delignification in a pressurized tubing system. Inning and unraveling 23 takes place, and then the finished fiber passes through the exit means 21 to the process system. A wash 24, optionally bleaching and a fresh wash 26, follows before exiting.

Figure 5 shows how to view a flow sheet for platyphytes; Consists of modules 27, 28 and 29, each with a pulp pump and consisting of a tubular system, while for the production of pulp from sawdust, hardwood and softwood. An example of a flow sheet is shown in FIG. The flow sheet in Figure 6 is different from the flow sheet in Figure 5. - Sheets are equipped with refiners 30, 31 and 32 for mechanical treatment, and Pressure screens 33, 34 and 35 are arranged after the refiner. this is, This separates the coarse chips from the received material and the processed coarse chips fraction 36. 37 and 38 are returned to treatment with fresh chemicals and mechanical treatment.

The three modules 27, 28 and 29 shown in FIG. It is rather common to use it for loosening and loosening, and these three operations are all Consists of digestion of the body.

According to FIG. 4, this impregnation, delignification and stripping 23 is followed by cleaning 24. However, it is still within the closed pressurized system 22. This “cooking” section is preferably The result is pressurized dehydration carried out in the pressure-plug thickener shown in Figure 1. The pressure concentration The apparatus is further described below.

The pulp from the digester can be transferred to the module for cleaning, and the pulp cleaning module FIG. 7 shows the transfer to the tube IV (50). In this module, there are three The pressurized dewatering presses are connected in sequence, and in the figure, these are three pressurized screws. Three pressure-plug thickeners with the pressure pump could be replaced with . As is clear from FIG. 7, cleaning from the bleaching section 39 The water or wastewater is injected before the last inlet of the pressurized dewatering presses connected in series. The pressed liquid 40 is recirculated before the inlet of the second pressurized dewatering press. . This is suitable for diluting the slurry after pressure dehydration and further transporting the pulp. This is done to achieve a pulp consistency of approximately 4%, for example.

According to Figure 4, the washed pulp still in the pressurized system is transferred to the bleaching plant. FIG. 8 shows how this transfer occurs and how the embodiment shown The bleaching plant consists of three modules each containing a tubing system with a pressure pump. 51, 52 and 53. As shown in Figure 4, bleaching The pulp is processed through three pressurized dewatering presses or three pressurized thickeners (modules). from the last bleach plant module V11.53 as well as from the last bleach plant module V11.53 Transported for cleaning. The pulp is diluted with liquid before each pressure dewatering. gas washing Clean water 55 from the purifier or heat exchanger is supplied before the last pressurized dehydrator, On the other hand, the liquid 56 squeezed into the last pressurized dehydrator is inlet to other pressurized dehydrators. is recirculated to the pressurized tubing system before the The liquid 56 squeezed into it can be recycled into the pressurized tubing system and/or into the initial pressurized dehydrator 58. Bleached before mouth; introduced into pulp.

The pulp 59 is transferred from the last pressurized dehydrator for storage or paper production. Ru.

The pulp during impregnation, delignification and loosening can be washed and, if desired, subjected to subsequent non-pressurized treatment. Bleached in-system. Such non-pressure cleaning is illustrated in FIG. Next, the cooking section 4 The pulp from 5 is in the washing plant module and is pressurized by three dewatering presses. Before entering module Vl, 48, which is used in the same way as for cleaning, 46 (if desired through a heat exchanger 47), but the three dewatering presses are of course No pressure is applied. After this non-pressure washing, the pulp is processed by known methods such as non-pressure bleaching. can be transported for dewatering or for storage or paper production .

Approximately 30,000 tons per year, or 100 tons per day, or per hour. Plant for producing unbleached or bleached cellulose pulp with a capacity of 4 tons per day can be built from the system described here, and the plant site and equipment Advantageous operation is obtained due to relatively moderate installation equipment costs. This manufacturing Diagrams and dimensions regarding capabilities are provided below. In addition, the factory consisting of this manufacturing capacity is The size is advantageous for new factories in developing countries.

As mentioned above, regarding the cooking section shown in Figures 5 and 6, With or without mechanical loosening done “in-line” , module 1127 as an impregnation module; Module I for Gushi! and II+, 28 and 298 are common It's a choice.

Examples of such factory work parameters are described below.

■Table 1) Calculated as dry NaOH based on bone dry fiber, Bacchus 2) Modification for material dissolution part operation 3) High value for sawdust, hardwood and softwood 4) Finely crushed chips 5) Reduced manufacturing capacity compared to 1. Plain plants 6) Based on bone-dry fibers < NH, OH and 7) Calculated as <Ox based on bone dry fiber 8) Old cardboard As evident from the bottom of the table, the use of refiners and pressurized screens are handled Depends on the raw material. However, the module was set aside for use in other machines. Designed according to standard arrangement with space.

Cooking is terminated in two different ways, namely a) preferably released Ordinary blowing combined with gas scrubber plant to recover heat from steam No need to use a tank and then recirculate the extruded cooking liquid and transfer it to the pulper. Use a pressure dehydrator.

b) With pressurized dewatering equipment, the system can be substantially simplified and furthermore closed system or and even more optimal heat savings.

Pulp washing is usually a desirable part of cellulosic pulp production. This is followed by a first delignification and loosening of the raw material and bleaching. By this method , a special cleaning module consisting of 1.2 and 3 cleaning steps after the initial dehydration (Module IV, 50 in FIG. 7 or module IV in FIG. 9) Ur! (See V148).

Regarding pulp bleaching, if the temperature of the pulp line does not exceed 100℃, the bleaching plastic Both the vent and the associated cleaning plant can operate at atmospheric pressure. In that case, this method After the washing plant in the cellulose mill (i.e. after module IV), It is carried out using a non-pressurized dewatering press in the wash section of the bleach plant. This is confusing It is also suitable for the module IV (50 in FIG. 7) to be pressurized. Because clean water form, or injected, such as effluent from a bleaching plant. The cooling caused by the addition of wash water causes a “cold blow” from the pressurized module. This is because it will be difficult.

However, the present invention provides maximum heat recovery and savings while at the same time reducing overall water consumption. makes it possible to obtain a significant reduction. so that the emission conditions are correspondingly improved. become. When the cold blow of pulp from the pressurized system moves to the wash section end of the bleach plant , maximum heat recovery is obtained. However, this does not apply to bleaching plants and associated Requires a pressurizing device to be used in the cleaning section. Therefore, there are two pressure options. Exists.

However, there are many situations where pressurized equipment should be used in bleach plants and their washing sections. There are many reasons. Once this is done, the bleach plant and its washing section will be Can be composed of modules, which are used for and attached to cellulose pulp reduction. It is the same as that used in the attached cleaning section.

The additional cost of machinery used in a pressurized system is less than the construction cost of a non-pressurized system. It is not relatively large. This situation requires resources to the entire pressurized system when implementing the method. The demand for books is not high compared to the capital required for normal cellulose processes. must be considered against the background of the facts.

Therefore, the use of pressurizing elements throughout the system reduces the mechanical requirements that must be used. This means that the maximum standardization of the elements is reproducible.

This standardization, in turn, offers significant benefits with respect to monitoring, maintenance and spare parts. and means savings.

Therefore, against the above background, a pressure bleaching plant with an attached washing section is It may be as shown in FIG. However, the pressure-plug thickener , preferably both module IV, 50 and module Vll+, 54 What is inside is noteworthy. In Table 1I below, as shown in Figure 8, Several operating parameters for operating a typical bleach plant are disclosed.

Hypo-hypochlorite opt, - as desired Without chlorine, i.e. NaOH1 or NH, OH, O, and/or If bleaching is carried out using only OL, the wastewater from the bleaching plant will be discharged into the washing section of the cellulose mill. The cleaning solution can be used as a cleaning solution for cellulose pulp from the cleaning section. recycled to the starting point of the process.

The method can be implemented using a high degree of self-regulation. Pulp pump in series Steaming plants and bleaching plants operating on pressure stages provided in , the pressure difference is adjusted by countercurrent recirculation of the chemical solution, and the fiber pulp is moved throughout the plant. let

As a result of the interconnection of such a cooking plant and a bleaching plant, resulting in only one place for discharge of waste from the plant. This discharge location is located further forward. may be located approximately at the starting point of the process, and as mentioned above, the "black liquor" to be recovered ”, as shown in Fig. 1 and Fig. transported to purified water and/or wastewater.

According to the Sankey diaphragm shown in Figure 3, the system is drained. The amount of used cooking liquor is planned as a cleaning solution for the subsequently bleached pulp. approximately equal to the amount of (clean) water added at the end of the test.

When large amounts of chlorine are used in a bleach plant, the bleach plant and its associated cleaning The return flow of wastewater and chemicals from the purification section is shut off before the cellulose mill and removed from the system. Branched out. This branch presupposes a new consumption of water in the wash section of the cellulose mill. ing. Such bifurcation then becomes inevitable due to the use of chlorine in bleaching plants. Causes increased water usage. Nevertheless, the present method - can be carried out using substantially less water than in the case of a mill.

Furthermore, if a moderate amount of chlorine is added in a bleaching plant, the chemical solution will return to the steaming section. It can be used as part of the cooking liquor. Furthermore, as is clear from Figure 1, chemical solutions and By applying heat and/or heat 6 just before the valve pump, many of the following can be achieved: benefits.

a) Processing temperatures above 100° C. can be used, increasing processing pressure.

b) each immediately as it advances to the next pressure step to pass through a new pulp pump; The pressure increases step by step over the pulp pumps arranged in the row.

C) Increased pressure at each stage reduces recirculation and fiber flow and chemical solution throughout the plant. It becomes possible to adopt the countercurrent principle between

d) Raw materials and chemicals are mixed intensively and this process is repeated steadily. obtained I: Due to the stirring and process chemicals, the fibers are "washed" due to the effects of the chemicals and stirring. ” and liberates some lignin.

The modules shown in Figures 5.6.7.8 and 9 are arranged in series; It is shown together with tube 60. For each module, both [package (pa ckage) J is shown as an example. This Chu The tube package includes a pulp pump, optionally a refiner and a screen. Can be assembled within the frame of a standard shipping container and is suitable for all serial modules The same applies to Figure 10 shows the assembly in such a standard transport container. It was shown to.

As is clear from the table above, the retention in each reaction tube package for each module is The residence time is about 10 minutes. The dimensions of these reaction tubes are as follows.

Tube diameter 1m Tube capacity 15m3 Total tube length 18m Each tube length: 4.5m A suitable tube quality is 5T23-33 with a wall thickness of 13IIl.

The quality of such tubes is guaranteed by an operating pressure of 20 bar and an operating temperature of 175 °C. withstand degrees. If desired, a tube of quality 5T23-43 with a wall thickness of 12 mm can be used.

Valves in the tubes for liquid circulation and liquid return shown in Figures 1, 2 and 3. is a pressure-operated automatic valve that opens at a set pressure. When this method is implemented, each process These valves automatically control the entire process as pressure increases occur during each step. By adjusting the counterflow between the fiber flow and the treatment chemical, the amount and 1. Liquid injected into the last step of the process through valve R3 in Figures 2 and 3 Determined by the amount of body (water). As is clear from Figures 1 and 2, this method When implemented, a self-regulating pressure distribution results. Clean water added (through RX) The amount is consistent with this embodiment and determines the amount of black liquor discharged from the system (through R1). Determine the concentration of solids in the black liquor by:

The pressure control automatic valves between the various pressure build-up stages shown in Figure 2 are also used throughout the process. By automatically controlling the backflow in the body, the counterflow between the fiber flow and the processing chemical controls the backflow. , whereby a pressure drop acts on the pressure control valve, i.e. the pressure control valve is disengaged. The degree of water or valve forced out of the slurry; designed to control the amount of liquid I get kicked.

Some of the chemical process conditions for this method consist of steaming, washing, bleaching and cleaning. Examples are shown in Table 1II below.

Table m Chemical process conditions including operating temperature and operating time in tube pulping systems fiber flow Table m (continued) liquid flow l) Other bases such as ammonia 2) With in-line mechanical stripping 3) Small amounts of AQ (anthraquinone) and surface actives such as surface active deinking agents agent As is clear from Table 1I+, at 90-150°C depending on the fiber material supplied. When varying cooking temperatures are used, the cooking chemicals may include sodium hydroxide, ammonia, etc. Steaming with oxygen or oxygen and optionally an auxiliary such as anthraquinone (AQ) Horse mackerel and bunt are used.

The total cooking time varies from 10 to 90 minutes depending on the fiber material supplied, but the desired amount of deionization is achieved. Good delignification of the regenerated fibers as well as dyes occurs over a period of 2 to 40 minutes.

Bleaching can be done with chlorine, O2, peroxide (r!1 elementary bleaching) or 0. alkaline using It is carried out in an atmosphere and the temperature is maintained at 70-120°C during bleaching. Steamed and Washing between bleaching is carried out at a temperature of 70 to 140 °C, and the washing time varies from 0.5 to 10 minutes. can be converted into Bleaching is followed by a final wash. As is clear from Table 1II , during which the fiber stream and the liquid stream are carried in opposite directions. Inside pressurized closed system Ammonia is very suitable as a cooking chemical because the entire process occurs in

For the pressurized system in which this method is implemented, it is already known that dehydration is performed as pressure dehydration. Stated. Furthermore, this dehydration is a so-called “pressure-rag thickener” or pressurized It also describes what can be done inside a screw press.

FIG. 11 shows such a pressure-plug concentrator with an immediately preceding pressure pump P. did. According to Figure 11, the pressure p, the friction between the sliding pulp plug and the tube wall When the resistance is reduced, the pressure P is greater than +++. Pulp in center dotted tube The plug is pushed out of the system through a conical discharge control means to the right in the diagram, while , the liquid forced out at pressure pII is directed towards the arrow indicated by the inlet to the circulation tube. It is circulated back to a location somewhat upstream in the process, as indicated by the direction.

Generally, the device shown in FIG. 12 can be used as an intermittent dehydration device inside the system. this is This corresponds to the dewatering device shown in FIG. 11, but in FIG. currently having a pressure of p, so as to further convey the pulp following dewatering in the The pulp is re-diluted to a lower pulp consistency, e.g. about 4%; In the mixer 70, one or two tube legs 71 and 72 are passed. is shown to be diluted with processing liquid that is returned to the pressurized tubing system.

These "pressure-plug thickeners" consist of standard centrifugal pumps for pulp; Designed for pulp suspensions of low or intermediate consistency, i.e. 6-15% consistency Similar to conventional pumps, it has no movable parts and can operate at operating pressures of up to approximately 15 bar. Dimensionally designed to.

As described below, when using high-pressure flashback, perforated tubes and It is required to dimension the jacket around the associated tubing system for higher pressures. .

To withstand the pressure created when many pumps are connected in series in a system, The pump should be certified for pressures up to 15 bar. in one pump The corresponding pressure head should be in the range of 10-20 m or more. difference In addition, the speed of the pump wheel and the diameter of the pump wheel depend on the textile material used. Addition to pressurized tubing systems at many locations along its length In order to obtain the desired mixing and dispersion effect between the gases, the circumferential speed is preferably 20 Advantageously dimensioned to be less than ~30 m/s.

However, the strength requirements for perforated tubes in pressure-plug thickeners are An outer envelope tube formed like a mantel around the perforated tube. The tube is insubstantial and therefore acts as a protection around the inner tube. Ru. The inner tube is therefore at the working pressure used, i.e. if desired Also relevant when performing high-pressure backflow at pressures up to 30-50 bar or higher. All safety regulations must be followed. For example, the inner tube is 1-5mm It can be made of acid-resistant steel with a wall thickness of .

A pressurized screw press is used for the final dehydration when carrying out the present invention. Ru.

A pressure-plug dehydrator or concentrator (hereinafter referred to as PPT) implements the present invention. It was invented for the purpose of Concerning its design, it consists of substantially simple measures in comparison. Liquid using PPT When extruded, relatively high fiber concentrations of up to 10-30% are obtained. The PPT is compact, does not require much space, and can withstand temperatures of over 100°C. and can operate at pressures substantially above 1 bar. The natural pressure limit of PPT is 15 bar, which is related to the strength of pump and tubing materials in pressurized process systems. This is the normal pressure class associated with the dimensional design. This situation implements the invention It opens new possibilities and degrees of freedom regarding the selection of temperature and pressure for and also allows complete and integrated utilization of the countercurrent components.

Pressure-plug thickeners consist of an internal thin-walled perforated tube that Other non-perforated tubes are placed as a jacket on the outside and around the inner perforated tube. The space formed between the tube and the outer tube includes a space between the inner tube and the space. Water or liquid that is forced through the inner tube due to the pressure differential is accommodated.

Continuously enters the inner tube as the pulp suspension is dehydrated and the pulp consistency increases. The plug of concentrated pulp that forms is passed through a perforated inner tube under suitable conditions. An axial force is applied in the direction of movement of the pulp suspension, and this force is applied to one end of the perforated tube. This is caused by the pump pressure applied to the This pressure is higher than the pressure in the surrounding tube. stomach.

In this way, the pulp plug is pressure-pressed towards the outlet end of the plug thickener. This frees up new capacity to expose a fresh perforated inner tube surface. is used for dewatering and concentrating suspensions containing fresh fibers entering the thickener. be done. Thus, new dewatering can only cooperate with the pulp plugs that have already formed. This occurs behind the pulp plug, and then this pulp plug is connected to the perforated tube. It continuously spreads and renews at the same rate as it flows out of it.

The pores in the tube wall become plugged and obstructed by fibers from the pulp suspension. The walls of the inner perforated tube are chosen to be as thin as possible to avoid Ru. Therefore, the wall thickness of the inner tube usually does not exceed 2 or 3 bar. Due to the stresses created in the material as a result of the pressure difference between the side and outer tube chambers Calculated and dimensioned with appropriate safety limits to withstand. However, before As noted, the outer tube is suitable for all safety requirements and given high working pressures. Dimensions should be made to accommodate any adjustments made to the pressurized tubing or steam system to be operated. must be determined.

When many pressure-plug thickeners are connected in series, many stages of dewatering and Concentration can be performed, and the pressure in the system reaches 2 Qbar in the final stage with continuous dilution. obtain. Therefore, the outer tube jacket of PPT can withstand such high predetermined working pressures. Dimensionally designed to withstand.

The movement of the pulp plug through the inner perforated tube is the last step in the process. determined by the exit means. The outlet means is compressed against the pump pressure in the system and Can it consist of a pressure-loaded elastic cone that maintains this balance? or the means is formed in a perforated tube in the last pressure dewatering stage of the pressurized system. In principle, two parts are opened and closed alternately to draw water to one part of the pulp plug. can consist of a sluice chamber in the form of a single tube between the loops. Ru.

When a pressure cone is used at the outlet of a pressurized system, the pulp plug is almost uniform under suitable conditions. Exit the pressurized system with continuous movement, while by using a sluice chamber, Rhythmic movement and movement determined by the speed at which the pulp in the sluice chamber opens and closes. The pulp plug moves forward and out of the pressurized system.

Press down to facilitate movement through the perforated dewatering tube inside the pulp plug. The inner and outer tubes are connected so that the expelled liquid briefly returns to the inner perforated tube. Space the inner dewatering tube in the opposite direction to the pressure drop between the chambers. It is necessary to send pressure impulses while This small amount of liquid allows it to pass through the hole. to temporarily reduce the fiber concentration in the outer plug layer opposite the perforated tube wall, thereby ``lubrication'' is obtained between the outer layer of the pulp plug and the inner surface of the perforated tube in the radial direction. It will be done. The result is an impulse movement of the plug forward within the perforated tube. Following an impulse injection of liquid, at the end of the impulse injection, the pressure drop ratio is Return to normal pressure drop ratio for dehydration and concentration.

Pressure - obtain safe sliding of the pulp plug through the plug thickener and What is required for the plug to obtain in the form of a cohesive plug is that the pulse considered in the axial direction The inner tube of the perforated tube is smaller than the internal shear force between the inner fiber layers in the plug. The purpose of this is to provide friction between the wall and the fiber plug.

Pulp pressure, pressure - pressure between the inner and outer tube chambers in the plug thickener Force difference, pulp suspension consistency, fiber type and degree of fiber crushing, perforated tube the wall thickness of the tube and the hole pattern of the tube and finally the surface condition of the inner tube surface. The pressure through the plug thickener depends on a number of operating parameters including Balsatory (p al-satory) and a short back compression of a small amount of extruded liquid. “Lubrication” that reduces friction is necessary.

Some examples of such pressure-plug thickeners and their pressurized tubing systems Examples of perforation degrees and perforation patterns for use in internal perforated tubes are given in Section 1. This will be described with reference to FIG.

The basic design of a pressure-plug thickener (PPT) is shown in FIG. Pal The pulp suspension is conveyed to pump 81, which further transports the pulp into tubes 82.83. and 84.

Surrounding the tube 83 is a tube 85 from which an outlet tube 86 is guided. was placed.

There is a seal 87 between tubes 82.83 and 85, and tubes 83.85 There is a seal 88 between the tube 83 and the external pressure chamber 90. These seals form an internal pressure chamber 89 that is sealed laterally to the configured the file. The arrows indicate the direction of flow of pulp suspension and water, respectively.

The structure allows the PPT to be opened easily, thereby opening the inner perforated tube 83. but easily replaced by new holes or other tubes with other hole patterns can be done.

PPT works as follows.

Pulp pumps typically have a fiber concentration of 3-6% at point A and pressure P.

(so-called MC pulp consistency (“medium consistency”), i.e. 6-15% fiber Fiber concentrations can be used, but this presupposes the use of special so-called MC pumps.

).

At point B, the pressure increases to P by the pump 81, and by the way, at this point B, the suspension The liquid has the same fiber concentration as at point A. Move from point B to point 0 through tube 83 The pulp suspension then flows through the holes in tube 83.

The pressure P2 in the tube 83 is greater than the pressure P in the outer ambient pressure chamber 90. Because of its large size, some of the liquid in the suspension passes through the holes in the tube wall, as shown by the arrows. and is pushed out. Most of the fibers of the pulp suspension remain in the tube 83. Accordingly, the fiber concentration in the tube 83 increases accordingly. Therefore, the The fiber concentration of the loop suspension gradually increases while the suspension moves to B or C.

The fiber concentration at the entrance to tube 84 typically varies between 10 and 30%, and the pressure Force difference (P2 P*), type of fiber, degree of digestion, degree of pulverization of fiber suspension, pattern of pores the area of space in the pore surface compared to the total tube area, as well as the parameter Existing conditions such as the diameter of the perforated tube with respect to the pressure drop and pressure drop (pi-ps) Depends on the matter.

Many PPTs can be advantageously connected to continuous pressurized tubing and separate pressure-plug As a result of pump pressure from pumps connected in series between The pressure increases step by step within the system. Approximately 2b for each pump and PPT unit There is a pressure increase of ar and 8 units are connected in series in the system described as an example. the entire system must be constructed to withstand a maximum pressure of approximately 16 bar. , furthermore, it is a normal class limit for pumps and tubing for pressurized systems.

However, as mentioned above, tube 83 is made of relatively thin tubing material, preferably Preferably, the desired hole pattern can be achieved by irradiation, for example with the aid of a numerically controlled laser. The turns are formed and the perforated sheet is placed on its inner surface before being bent round and welded to the tube. Made from polished, thin acid-resistant steel sheet with a thickness of 0.5-2.0 mm Wear. The pump used is a normal centrifugal pulp pump.

Regarding suitable evacuation means for the end of the pressurized system, as described below with respect to FIG. 15, for example, An equilibrium point is obtained for the pressurized movement of the pulp suspension through the pressurized tubing system; Here, the final pressure of the pressurized system - the pump pressure at the inlet to the plug thickener (P,) is Pressure applied against the evacuation means and the pulp plug, inner tube wall and evacuation balancing the frictional forces between the means (shown in the form of a discharge cone in Figure 15); Ru.

Pressure - perforated for the formation of cohesive mobile fiber plugs within the plug thickener The inner diameter of the tube plays an important role as well. Because the resulting total The axial force of the pump pressure in the tube cross section increases in proportion to the square of the tube diameter, On the other hand, the internal friction force between the pulp plug and the inner tube surface is The length of the tube increases only in proportion to the tube diameter, except for the length and length of the tube. Therefore Therefore, if the pulp plug has a sufficiently high fiber concentration, this type of plug will By increasing the diameter of the tube, it can be moved more easily.

Pressure-Plug thickeners are used to increase pressure as the pulp moves through a perforated tube and exits. The valve plug formed therein encounters an obstruction in the form of a tapered tube cross-section. It is important that the structure is configured in such a way that it does not cause any problems.

Figure 14 shows how pressure-plug thickeners are connected in series in a closed pressurized system. Show what you can do.

Concentrated pulp suspension at point D showing fiber plugs with fiber concentration of 10-30% The suspension is forced into a dilution chamber 91 where it is passed through an inlet tube 92. diluent is supplied. A pump 93 pumps the diluted suspension into a pressure-plug system. 94, where the pulp is again desorbed as described above with respect to FIG. Watered. The concentrated pulp is moved past the G point by pump pressure to a new dilution chamber. -97, which chamber is similar to dilution chamber 91 and has a pressure plug. It has the same main dimensions and the same design as the thickener, but with a distinctly inner perforated chimney. There is no tube.

When the concentrated pulp is mixed with the diluent in chamber 97, the diluted suspension is It continues to pass H point and is transferred to pump 98, and then the concentration operation is carried out in PPT 99. is repeated.

Figure 15 is placed as the last step in the cellulose process or cleaning process. pulp thickener (PPT). In Figure 15, from the pulp thickener Stop element 101 at the outlet end of the tube is shown, and this stop element 101 is preferably a conically shaped device. , pressure is applied to the pulp flow within the tubing system by applying pressure to the stop element. An adjustable pressure member that applies a force, preferably an air bellow ) 102 at its tube end. The pressure P, is varies depending on the formation of the plug within the tube. The first valve plastic formed The fiber layer increases in length in the direction of K in the tube, and the fiber layer is on the inner surface of the perforated tube. By covering more and more of the surface, the liquid flow is retarded and the pressure P increases.

A fiber plug covers the entire length of the perforated tube from L to K and Maximum pumping pressure occurs when liquid flow nearly stops. Air bellow 102 pressure Equilibrium is obtained by controlling the I; Pressure is the frictional force from the pump pressure P4 against the inner tube wall and cone surface. Balance the valve travel by minus Pulp plug is almost constant Therefore, this equilibrium is automatically maintained during operation. Pulp plug length extension When the condensate valve covers the pores and causes an increase in inlet pressure, the pressure increase is caused by the concentration valve cone more is drained across the area, most of the perforated area is uncovered, the pressure decreases, and the bulk nce will recover. Figure 16 is another example of the final concentration step of a pressurized valve suspension system. shows. According to FIG. 16, the discharge is controlled by a discharge sluice, which , each placed at a certain distance from each other in the same tube and opening and closing alternately. It consists of a pole or calotte valve. the valve The flow port 107 of the valve is at least as large as the must be equal to the cross-sectional area of the tube 108. This type of discharge sluice is The concentrated fiber suspension, or pulp plug, discharged from the pressure system to the atmosphere is Used when the temperature is above 0°C, the valve 106 is opened to the atmosphere, while the valve 106 is opened to the atmosphere. When 105 is closed, internal steam is released. The valve then connects the sluice and the valve. extruded or blown out. The total sluice volume is therefore It is blown out until it runs out, and at the same time it is filled with steam at atmospheric pressure. tube 10 Close the valve 106 to let out the next part of the pulp plug in the valve 105. When opened, the steam or air in the sluice reaches a pressure corresponding to that of the pressurized system. A space is obtained for the new part of the pulp plug that is compressed and drained from the system. It will be done.

Under certain manufacturing conditions, valves 105 and 106 may advantageously have a special shape. and has a cutting design that can better split or cut the pulp plug. It may also be designed as a flap pulp with a flap (Nap).

FIG. 17 shows the same sluice means as shown in FIG. 16, but with the inlet tube 11 0 and the contents in the sluice 112 do not themselves come out of the sluice. A valve ill is provided for use.

Furthermore, two valves 113 and 114 are each shown, with valve l13 closed and When valve 114 opens, pressurized air is supplied. This is because valve 111 is open. The contents of the sluice exiting the system through valve 114 are then blown out. It is et al. Valves 111 and 11 are then connected as described above with respect to FIG. 4, open l (lube 113, and insert the next part of the pulp plug.

Figure 18 further moves the pulp plug into and out of the thickener. Indicates the means to do so. Pump 115 and various parts 11 constituting the thickener 6.117, 118 and 119 were previously described with respect to FIG.

The means are disposed within outlet conduits 119 and 122 and provide a connection from tube 121. Consists of a 3-way valve with feed, which is less than the pump pressure in the valve tube. A liquid or gas is transported at high pressure.

Arranged as a connecting link between divided valve tubes of a pressurized system, e.g. A flexible tube connection 123 in the form of a rubber collar occurs within the same tube. Capable of regulating and absorbing short pressure pulses.

This is a membrane expansion tank 124. This tank contains the pressure valves expected to occur in the system. dimensioned to match the

The means operate as follows.

According to Figure 18A, the dewatering of each concentrating fiber valve is as described above with respect to Figure 13. arise in the same way. Move the pulp plug into and out of the thickener Short-term reversals of the pressure in the pulp thickener are carried out at regular intervals to Ru.

This is clear from Figure 18B, which shows how the three-way pulp 120 Slightly rotate 90° clockwise near outlet 122, and at the same time, the chemical solution in the water or a mixture of gases (e.g. oxygen) through outlet tube 119 at high pressure in the opposite direction. into the outer pressure chamber 116 while first removing the tube 117 from the valve suspension. It shows how the liquid pushed in is pushed back into the tube 117 through the hole.

The amount of liquid forced back into tube 117 through the hole in the case shown in FIG. 18B is , the width of pressure I; is the length of time during which external pressure is recognized to be effective, or It can be adjusted by both. Lubrication between the pulp plug and the inner surface of the tube here The amount of liquid is very small, so for many reasons The original fiber concentration of the pulp plug, which is desired to be as high as possible, has little or no Not important at all.

After a short period of injection of "lubricating" liquid into tube 117, as shown in FIG. 18B, , so that while the pulp plug is moving, the three-way valve 120 is moved as shown in FIG. 18A. The position is then reversed to the same position, followed by a new plug of concentrated pulp. formed and the same cycle as above is repeated.

Figure 19 is written for the PPT shown in Figures 18AS 18B and 18c; shows a PPT with the same function as that of Instead of a 3-way valve and isolation tubing system back to the tube, the pressure-plug The liquid extruded from the gum thickener is used here for the same purpose.

Thus, FIG. 19 has a piston 127 in the outlet tube 125; A cylinder actuated by an actuator, such as an air bellow 128 126 is placed. The position of the piston is as shown in Figure 19A. If so, dewatering and thickening of the pulp suspension occurs as described above.

FIG. 19B shows that the movement of the piston into the upper position in a short period of time as shown in the figure The outlet flow from tube 125 is blocked and further described above with respect to FIG. ;The liquid volume ΔV depends on the dilution and "lubrication" action as pressure - plug thickener. Pressure due to being pushed back to - A change in the pressure state inside the plug thickener occurs. . As shown in Figures 18A and 18B, a short pulse of pressure is applied to the elastic tube. It is regulated by a connection 123 or a pressure tank 124 or similar means.

Figures 19C and 19D show a method of operation for a similar device, but in which the piston 1 31 and movable element 130 constitute a branch from outlet tube 125 do. FIG. 19C shows the pressure-plug thickener with which tube 125 is connected. Pulp and piston position during pulp dewatering and concentration in perforated tubes Indicates the location.

FIG. 19D shows a short period of closure of pulp 129, in which piston 131 is displaced. Moved by movable element 130 towards outer tube 125 . that As mentioned above, the pressure state inside the plug thickener is reversed, and the perforated Liquid moves through the holes in the tube.

Figures 19E and 19F illustrate the pressure-plug thickener principle and the outlet tube After the pulp 136 is adjusted to close 135, the pressure-plug thickener between the outlet tube 134 from the adapter 133 and the outlet tube 135 from the adapter 133. The outer pusher presses against the inserted elastic tube connection or adapter 133. A pressure body 132 provides a counter-pulsing pressure. The adapter 133 is a suitable It can be made of rubber or other elastic material that can withstand pressure and temperature. reverse This means of providing pressure pulses of Of another interest, in this case the valve suspension has a relatively low temperature below 100°C. do.

Figures 20A, 20B, 20C and 20D show pressure-plug thickener and fiber Different types of holes for the inner tube l17 of the fiber sorting means (the latter will be described later) shows.

Figure 20D shows an I ; indicates a tube with a relatively large opening; Figure 20D, ■ indicates the tube. Figure 20D, 11 showing the wire mesh or wire screen and openings from the outside. Viewed from inside the tube; showing wire mesh and openings.

FIG. 20E, l is a cross-section through the tube wall with attached fine wire mesh. shows how the fiber suspension is concentrated against the wire mesh during dewatering; FIG. 20E, 11 shows a cross section similar to ■, and shows the pulp formed in the tube. The formed fibrous volume forming part of the rug is extruded; Shows how the body's pulsating back pressure pushes it back inside the tube. through wire mesh The liquid is forced back into the tube in the path of least resistance; Distributed as a layer between the pulp plug and the inner surface of the tube wall.

Thereby, the friction between the pulp plug and the tube wall is reduced, and the nokuru plug is It is pushed forward in the tube by the pump pressure in the direction of the densely drawn arrow. under the wire mesh In the tube wall of , rough slits may be removed instead of round holes.

Interesting examples of holes in pressure-plug thickener tubes are Nos. 20A, 20B, 2. Interesting measurements and dimensions of such holes are shown below by figures 0C and 20B. It is clear from Table 1V below.

The TPS process is also separated from the pressure system through two separate outlets, It involves the separation of the fibers of the conveyed pulp suspension, i.e. long fibers and short fibers. pressure Power - the same element as previously described for Bragg Thickener (PT) Separation takes place in a device built from

The separation or fiber separation is shown in FIGS. 21A and 21B, which are 1 to the elastic tube connection 142 or other aforementioned pressure-pulse balancing means. Pass the diluted pulp suspension from the previous low pressure stage through the stages into perforated tube 143. Indicates whether to transfer. However, the separate holes in tube 143 are substantially free of pressure. It is larger than the hole mentioned above for Bragg Thickener (PPT). Outside of tube 143 and a tube 144 disposed about it, whereby inner tube 14 3 and the outer tube 144 is connected to the cylinder 146 by a space. The piston is pneumatically controlled and is designated as air plow 145 in the figure. Moved by the actuator shown. By reciprocating the piston, the inner Pulsing with alternating pressure drops in both directions across the hole in side tube 143 Pressure is created. As the piston moves from pump 141 toward outlet 159, This pulse of pressure forces the fiber suspension several times into the hole and squeezes it out of the hole. do. Therefore, these holes in the inner tube 143 cause a sorting action, Next, the long fibers of the pulp suspension are preferentially left in the perforated tube 143, while Short fibers easily pass through the pores. Therefore, the short fibers are inside the perforated tube 143. and the outer tube, and then they are pressure-plugged It is discharged from the system through thickener 150. This inner perforated tube 143 and The process of sorting or sorting the fibers, which takes place between the surrounding spaces, is a pressure-plug process. Contrary to what happens in the pulp, the pulp is not dehydrated or thickened.

This creates an air gap within inner tube 143 and between tubes 143 and 144. This means that the pulp consistency between them remains approximately the same. After fiber sorting, short fibers and long fibers are passed through the separated suspension or pulp from the pressurized system, respectively. Pressure-plug thickener 1 with associated outlet sealing means 151 and 159 50 and pressure-plug thickener 158 . Two pressures - plugs The function of the thickener 150 is similar to that disclosed with respect to the pressure-plug thickener shown in the other figures. It is the same as it is. However, two pressures - plug thickener 150 and 158 must have holes of different sizes. Because long fiber painting minutes, i.e. pressure - The hole for the plug thickener 158 is intended for short fibers; Force - This is because the dimensions must be larger than the hole for the plug thickener 150. be.

The outlet means 151 and 159 each consist of a pressure loaded cone as shown. or a sluice means with two pulps as described above. moreover, The outlet means, under preferred circumstances, consists of a single flow rate or pressure controlled pulp.

The illustrated pulps 147 and l52 (R, and R3) each have two fibers. Automatically control the desired flow rate between fractions. Thus, the suspension through R6 The decrease in volume further increases the concentration of long fibers in this fraction, which has a larger capacity. However, both portions transported through R1 mainly contain short fibers. Similarly, R, Due to the relatively large proportion of fibers throughout the fibers, a large amount of short fibers are distributed along the long fibers. He is carried away.

The illustrated cylinder piston 154 moves in step with the closing valve 156. , similarly piston 162 moves to the opposite side as shown in Figures 22A and 22B. do.

The illustrated pressure equalization tubes 188 and 155 represent the pressure in tubes 143, 149 and 157. Attenuates and partially reduces the force pulse.

Pistons 154 and 162 act against closed valves 156 and 161, respectively. Used for flashback through the holes in pressure-plug thickeners. The fluid pressure generated is controlled by an o - secured using a bar flow valve (not shown).

The pressure change within tube 144 caused by piston 146 causes Much less than the pressures occurring within 1548 and 150. Because piste When the pressure drop occurs alternately in both directions due to the movement of the tube 146, the twisting of the tube 143 occurs. The large pores cause a slight flow resistance, which results in a more rapid pressure equilibrium. This is because Furthermore, due to the relatively small pressure drop in the coarsely perforated tube, Safety measures in the form of overflow valves are not required here. As mentioned above, Pressure - The liquid forced out of the plug thickeners 158 and 150 is 160 and back into the overall process fiber stream.

In 21A and 21B, actuators 153 and 163 are shown. , they move at frequencies such that they always act in opposite directions, i.e. with parallel translation. It doesn't move. Furthermore, the actuator 145 is connected to the actuator 153 and It can move regardless of the 163 movement frequency. Furthermore, the actuator 145 has continuous and uninterrupted reciprocating movement, while actuator 153 and 163 is a brief period of liquid pushed back through the holes in tubes 157 and 149. 7 To withstand the 7-rushback, two short-duration pumps against the closed outlet valve are used. las movement, which maintains the movement of the valve plug from the pressure system as described above. be done. When the movements of actuators 153 and 163 occur simultaneously, the 22nd A and 22B, for example, this causes the actuator 14 to 5 reciprocates several times each time the actuators 153 and 163 act. I can move.

The holes in the tube 143 used for fiber separation are used to separate the types of fibers contained in the valve suspension. The dimensions shall be designed according to the type. For the discharge of long and short fiber fractions The same applies to the pore size design of the pressure-plug thickener used. below Examples are given in Table 1V of Table 1, as well as hole design and dimensions.

■Table 1) The dimensional design should be considered within wide limits to account for the large differences within the fibrous structure of the suspension. It's true.

2) American Sieve Series-ASTM E-11-61゜ji! Figure 22 shows the pressure-plastic Gusickener (PPT) serves as a sluice means for discharging pulp from the system. Accordingly, it is shown how they can be connected in series and act simultaneously.

FIG. 22A shows dilution water flowing into dilution containers 171 and 172 and their respective outputs. three interconnected ports with liquid exiting from ports 179, 180 and 181; The figure shows a typical dehydration and concentration situation using PPT. Pulp 173 is closed When pressure is applied, the fibers formed continuously in the perforated tube inside the pressure-plug thickener No axial movement of the fiber plug is observed.

FIG. 22B shows the same system as shown in FIG. 22A, but with pulp 174 closed. After opening the pulp 173, the pressure drop in the pressure-plug thickener was reversed.

Thereby, as detailed above with respect to Figures 6 and 17, the pressure-plug The pulp plug in the puller 170 is connected to the outlet sluice between pulps 173 and 174. can be placed in

Further, in Figures 22A and 22B, injection means 176 and 177 are shown, respectively. 168.1 and they simultaneously pressure-plug the extruded liquid 69 and 170, the pulp plugs therein are simultaneously "lubricated" and the pulp plugs are As a result of the pumping pressure that the pulp pump simultaneously exerts on the pulp plug, the outlet sluice is filled with pulp plug; residual steam until it is filled or through which it is finally emptied. By compressing the air from the sluice, the pulp plug simultaneously moves towards the outlet sluice. pushed forward. caused by injection means 176, 177 and 178 The pressure pulses are applied by dampers 182, 183 and 184, respectively, as described above. Captured. Pulp 173 is then closed, pulp 174 and The pulp 175 (the latter for blowing the sluice chamber) is inserted into each outlet 179. ．． Inlet for fresh outlet of liquid forced through 1801i and 181 It is opened simultaneously with the opening of members 176, 177 and 178.

The same pressure pulse cycle is then repeated. Pressure pulse inducer ( 1nducer), the other means described above with respect to FIGS. 18 and 19 are similarly Can be used in any way.

A flow sheet that is more detailed but otherwise corresponds to the 70-sheet shown in Figure 1. is shown in Figure 23. In particular, the three reaction modules M, %M, and M3 are This is shown in more detail in Figure 3, and as is clear from the figure, there is a chemical liquid in front of each pump. There is a tube mixer 70 for mixing pulp slurry and pulp slurry after each pump. is arranged with means constructed in the same way, but which means serve as a distributor for the medicinal liquid. Function. Furthermore, the liquid 7 pushed out from the first dehydrator on the left side of FIG. 0 uses the supplied clean water 9 or the waste water from the bleaching plant before leaving the system. It is transported for heat exchange. Water consumption is controlled by control pulps R1 and R2 Ru. 5 principles of countercurrent flow and this method! Further details on the combination of chemical additions to be applied Figure 24 illustrates the principle of process operation. Further demonstrate these principles The figure shows the main steps: delignification (deinking if desired), washing, bleaching and rewashing. The number of circulation and return routes depends on the number of pumps and thickeners used.

Similarly, the number of locations for adding chemicals will vary depending on the number of different raw materials and Depends on the fiber pulp used. As is clear from Figure 24, "tube pulping system" or the countercurrent source used to carry out the method, referred to as the "TPS method" for short. Due to the process, cellulose production can be integrated in-system and injected into the system at the end of the process. The wash water is first converted to a bleach solution and then ripened on the way to the start of the process. and is converted into a cooking liquid by adding a chemical solution. Sankida shown in Figure 3 As is clear from the diagram, when the cooking liquid leaves the system at the beginning of the process, On the way to the starting point of the process, the same liquid absorbs dissolved substances from the feedstock and transfers this to the system. Carry it outside.

During the process, the pump recirculates and reuses the cooking liquid and chemicals, as well as Mixing and dispersing, stirring and This results in a "washer effect" within the system, and further internal heat exchange.

In Figure 24A, A is the cleaning area, B is the bleaching area, C is the cleaning area, and D is the impregnation and deriging area. Indicates areas for cleaning and deinking if desired. As previously described, chemical solutions or heat 192 was added before the processing liquid was transformed into a cooking liquid and/or a deinking liquid by the addition of The cleaning liquid 190 is changed into a bleaching liquid by adding a bleaching chemical liquid 191. With this method, Water consumption is greatly reduced compared to that of normal cellulose distillation solutions. mentioned earlier. This ensures that the same pulp consistency is maintained throughout the process. is possible. This is because the process (TPS method) involves pump impregnation, steaming, This is because it is carried out in a continuous, closed, pressurized tube system where bleaching takes place as desired. In addition, pressure dehydration equipment is installed for dewatering pulp and reusing chemicals and heat. This is because it is used in the “line of Machinery can be simplified accordingly and cellulose can be produced without runoff into natural waters. Ru.

Determining water consumption when producing pulp with approximately 50% yield by TPS process An example calculation for this is shown below.

Assuming that a fiber raw material with a solid content of 33% is fed to the TPS process, the absolute dry content is The calculated amount of raw material is 2 kg. At the beginning of the TPS process, black liquor is the first Extruded into a pressure dehydrator, the black liquor contains approximately 1 kg of dissolved solids. . At the end of the TPS process, just before the last pressurized dehydrator, water (washing water) is injected and the amount of water is X liters per kg of cellulose produced. Guessed. The cellulose fibers produced contain the same amount of solids as the raw material, i.e. 33%. It is estimated that from the 2 kg of raw material initially introduced, 1 kg of fiber and the dissolved 1 kg of solid remains. The solids are dissolved in the injected liquid and the final pressurized dehydrator 1 kg of fiber is removed from the system after , while having solids dissolved in it. Injected I; the liquid is carried back into the fiber stream towards the start of the process.

The theoretical maximum that must be used to obtain the conditions for cellulose to be produced. The amount of marginal water, returning liquid and drained black liquor is calculated as follows: It can be simplified as much as possible. If the black liquor contains 15% dissolved I; If provision is made for evaporation, the minimum theoretical volume of liquid (X liters) is -15/100-10 X-100/15-6.7 (Water amount/A fiber 1kg) and 6.7 tons of water for each ton of cellulose fiber produced. .

This very small amount of liquid supplied per ton of cellulose produced is usually Compared to the normal water consumption when producing cellulose using the cellulose production process of It is also significantly less.

The situation in which the present TPS process is carried out in a continuous closed pressurized system means that the cooking liquid, For example, it is very suitable for using NH and OH, which easily generate volatile gases. I'm going to do it. This is because the effluent leaves the process only at certain points and in a controlled manner. degassing of the liquid can occur at the same time as recovering the chemical solution and heat.

For example, recovery of chemical solutions from liquids such as NH and OH that easily generate gases is difficult. This can be done by adding a basic agent which increases the evaporation of the evolving gas. Steamed liquid When using NH,OH as an agent to increase evaporation, CaO or Ca0H can be used in the form of powder or slurry. Next, waste liquid When the gas exits the pressurized system, the remaining process-borne NH, is liberated and passed through the gas scrubbing system. By being absorbed by the clean water in the runt, new cooking chemicals such as NH, OH At the same time as NH is formed, the heat content of the gas is recovered.

The countercurrent principle used to carry out the method requires the aid of extra mechanical equipment. Deinking of recycled fibers from printed matter of various qualities within the scope of this TPS without enable. Supported by special chemicals added at this stage of the process; Deinking is carried out within the pulp either before the pulp reaches the stage of delignification or at the same time. and optionally followed by bleaching. Suitable drugs to facilitate deinking The liquid is a nonionic surface active nonylphenol alkene oxide adduct.

This method pre-cools the liquid-fiber mixture to below 100°C before discharging it to the atmosphere. By releasing the pulp from the pressurized system without "explosion pulp" can be produced. In this situation, the book The novelty of the process is the relatively high pressure in the system, e.g. 15-2 Qbar. (depending on the number of pumps) and at a relatively low temperature in the pressurized system, i.e. 110-150°C ``explosion'' of pulp is possible. Because pressure and Unlike normal cellulose production, where the temperature and temperature are determined by normal saturated steam, This is because the pressure and temperature used within the TPS can be selected independently of each other. Book The advantage of low temperature during the process is the temperature of saturated steam at high pressures such as 15-20 bar. Contrary to the case of extreme high temperatures corresponding to It must not easily deteriorate or be damaged.

1, 2 and 3, the first pressure increasing means of the TPS is a pump P, . However, in order to prevent the generation of steam within the system, the desired temperature within the system is If the corresponding pressure is to be increased, the TPS Can be supplied with bomb.

Furthermore, it is highly flexible to the different raw materials being processed and the fiber pulp being produced. What can be applied in a soft manner is the present TPS process and the time to implement this process. ; general characteristics of equipment used for this purpose.

We have described bleaching using O7, which of course does not release O□ in the process. Supplement bleaching by adding chemicals such as peroxide.

Pressure - the above 7 lashes of liquid returned to the perforated tube of the plug thickener Apart from providing "lubrication" between the fiber plug and the inner surface of the perforated tube, It has further effects. Inside the perforated tube by applying backflushing. pores employ high backflush pressures and the resulting high speeds of backflushing. Free of fibers and other solid substances by flush liquid. backflush Pressure is adjusted by normal overflow valve adjustment as previously described (not shown). controlled by The backflush pressure used will vary depending on the manufacturing conditions involved. and varies in the range of 1O to 5Qbar, preferably pressure-plug thickener The pressure inside the inner tube is more than 3-40 bar. The pressure is placed in series pump, i.e. increases due to pressure increase at each pumping stage, 0.5-1Q bar range, preferably not exceeding 5 bar.

An industrial-scale plant implementing this process would produce approximately 100 tons per day. The pressure used to carry out this process - for the plug thickener, has a capacity of A suitable length is a 2-5 m long tube with a perforated tube of 100-400 mm diameter. Corresponds to a hole tube.

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Claims (1)

[Claims] 1. The fiber feedstock is introduced into a cooking zone where it is exposed to oxygen and oxygen in an alkaline slurry. and optionally incorporate small amounts of other adjuvants, such as anthraquinolines. Cooked and delignified under high temperature and pressure using a combined alkaline cooking chemical solution. , the cooking liquor is cooked in the form of black liquor, which is stored or transported for recovery of the liquor. or paper, cardboard, fiberboard and other plant materials removed from the delignification process. producing pulp suitable as raw material for wood and/or products containing wood fibres; plant and wood fibers are cooked or delignified and optionally chemically or mechanically A method of pre-deinking fibers from mechanical pulp, optionally followed by bleaching, comprising: The pulp stock in the form of a pumpable slurry is processed through cooking, delignification and the desired During pre-deinking and optionally subsequent bleaching, the slurry and Continuous processing in a sealed manner with a pump used simultaneously as a mixing assembly for It is conveyed through a pressure system and repeatedly removed while the pulp is entrained through the tube threads. The watered liquid is forced out and the process is carried out before each dehydration step apart from the last dehydration step. The liquid pushed out from the process and the dewatering step downstream of the process and/or Diluted by liquid recirculated from downstream pumping stages of the process, the pulp step by step in one or more pumping stages while the pump is routed through the tubing system. The pressure is increased and the final dehydration step is optionally cooled and supplied under pressure. Diluted with clean water and/or bleach solution and carried out in a pressure cooking or delignification system. After the final dewatering process, the pulp is washed and optionally subjected to a continuous pressure system or A method characterized by bleaching while performing cold or hot blowing in a non-pressurized state. 2. The raw material is cooked and bleached using the same equipment assembly for cooking and bleaching. A method according to claim (1). 3. disrupted only by a short period of increased pulp concentration just before each pressure dewatering step. fiber raw material throughout the process by maintaining essentially the same pulp consistency A method according to claim (1) or (2) for carrying. 4. Claims (1) to (3) using the same basic active ingredient throughout the process ) The method described in any one of the items. 5. Special properties using sodium hydroxide or ammonium hydroxide as the basic agent A method according to claim (4). 6. carried out using a controlled pressure higher than the saturated vapor pressure at the working temperature employed. A method according to any one of claims (1) to (5). 7. The finished fiber pulp is removed from the pressurized tube system under “explosion” conditions. A method according to claim (6). 8. In the patent claim, the chemical liquid is added at various stages of the process and at various pressurization steps. The method according to any one of ranges (1) to (7). 9. Ammonium hydroxide is used as the basic agent, and black liquor is removed from the pressurized system. The black extruded from the fiber pulp in the first pressure dehydration of the process before being A base of calcium paste is added to the liquor, thereby subjecting the black liquor to pressure relief. Gaseous ammonia is then expelled from the black liquor and absorbed into the water. The ammonia expelled by this process is collected, and the ammoniacal solution obtained in this way is Claim No. 1 introduced into the cooking or delignification process as a new cooking liquor The method according to any one of (1) to (8). 10. Thick-walled outer tube dimensioned according to the pressure employed in the process The pulp slurry is dewatered by forcing it into an enclosed thin-walled perforated tube. The pressure in the space between the inner perforated tube and the outer tube jacket and the inner Due to the pressure difference between the perforated tube and the Substantially all of the fibrous material is extruded radially from the side tubes. Patent claim that the pulp is concentrated into a pulp plug by leaving it in the inner tube The method according to any one of items (1) to (9). 11. The final pressurization is the means to discharge the concentrated pulp slurry from the pressurization system. provided in the dewatering process, the evacuation means being located at the end of the outlet tube from the pressurized system. pressure against the internal pressure of the system and against the pressure of a pressurized air perot or similar pressure means. Claims consisting of a conical stop device that balances the internal pressure applied by The method according to any one of paragraphs (1) to (10). 12. The concentrated fiber plug formed in the pressure dehydrator is sent to the pulp pump just before it. The pump pressure generated by the pump is carried through the dewatering device, and the The pressure differential is intermittently reversed and the liquid returned through the holes is disconnected into the inner tube of the dehydrator. By continuously pushing the male plug, moisture is created between the outer periphery of the male plug and the inner surface of the perforated tube. By creating a sliding effect, the forward movement of the fiber plug in the pressurized dehydrator is prevented. A method according to any one of the appended claims (1) to (11). 13. When one or more pressure dehydrators are used in series, the Intermittent reversals of the pressure differential in the pore tube wall cause the fibers from the fiber pulping system to Claim (12) states that the process is performed in synchronization and coordination with pulp discharge. the method of. 14. For the final pressurized dewatering step, there is a formed between two alternatingly operated pulps spaced apart and a discharge means in the form of a discharge sluice. 0) The method described in any one of paragraphs. 15. The discharge sluice is connected to a pressurized system, preferably a pressurized air line, which connects the discharge sluice to the sluice. By opening the inlet pulp, the discharge sluice is virtually flushed at the same time as it is discharged The method according to claim (14), wherein the method is performed by washing the skin with water. 16. The pressure dehydrator is extruded through a hole in an inner tube within the pressure dehydrator. An outlet tube for the extruded liquid is provided, the outlet tube for the extruded liquid. At the same time as exit flow is stopped, liquid or gas flow at high temperature enters in the same exit tube. It is operated at short intermittent intervals to open for A three-way pulp is provided that causes backflow to the extruded liquid, and Elastic pressure pulses caused by liquid flashback through the pores Pulp conveying tube located just before the entrance to the pressure dehydrator to capture using an elastic tubular connection within the tube or connecting to a tube for transporting the pulp into the pressure dewatering unit. caused by flashback of liquid through the holes in the inner tube. a membrane pressure tank immediately in front of the elastic tubular connection to capture the pressure pulses The method according to any one of claims (12) to (15) to be used. 17. Pressure dewatering device for forcing liquid out of the outlet tube or pulp slurry using a piston cylinder placed in a tube from a dehydrator or a dehydrator. a pressure pulse is provided and the piston is pneumatically or hydraulically operated; Inner channel with sealing pulp and sealing device for liquid flow forced through outlet tube. for a short period of time to flash pack the liquid forced through the holes in the tube. Outlet chute with pulp in closed position operating piston to cause back pressure It is operated by a piston cylinder placed in a tube branching from the tube. The method according to claim (16). 18. pressing the elastic tubular part with the exit pulp from the closed exit tube; The liquid extruded from the pulp slurry is flushed through the holes in the inner tube of the dehydrator. The outlet tube from the pressurized dehydrator is used to create back pressure for A pressurizing device is applied to a device for forcing liquid out of a pulp or pulp lee. The method according to claim 16, wherein an elastic portion is provided. 19. Before being discharged from the pressurized pulp manufacturing process, it has relatively coarse pores. a tube surrounded by an outer tube forming a jacket around the inner tube The pulp slurry passes through the pores and is short-circuited by pulsing the liquid flowing in and out of the pores. Fibers flow out through the pores and form between the inner and outer tube jackets. into the space, branching the short fiber slurry from the outer tube and removing the par from the process. Before discharging the slurry, the slurry is passed through a final pressure dewatering device, while fiber separation means The long fiber slurry from the inner perforated tube is passed through the final pressure dewatering device and then Claims for dewatering the pulp slurry before discharging the pulp from the process The method according to any one of items (1) to (18). 20. The holes in the inner tube of the fiber separation means provide pressurized dewatering for long fiber pulp slurry. The pores in the inner tube of the device are coarser and pressurized dewatering device for slurry of short fibers. The method according to claim 19, wherein the pores of the inner tube are coarser than the pores of the inner tube. 21. A pressure dewatering device for providing concentrated pulp plugs under pressure, comprising: At the end, sealed against the inner tube and able to withstand higher pressure than the inner tube an inner perforated tube surrounded by an outer tube of material capable of Contains the extruded liquid from the pulp slurry in the perforated tube on the side, and the extruded Liquid or other flushing medium between the inner perforated tube and the outer circumferential tube from there through the holes and back into the inner tube. an outer tube with one or more outlets (3) for In order to carry out the method according to any one of claims (1) to (20), Equipment used. 22. The hole comprises a hole through the inner tube, and the hole is different from a hole through the tube wall. Patent covered by a wire mesh or screen having substantially small mesh openings The device according to claim (21).