A chemi-mechanical pulp system

Abstract

The present invention discloses a chemi-thermomechanical pulp (CTMP) system. The CTMP system includes a high-consistency refiner, a bleaching and washing device, a first double-roll washer, a de-aeration tank, a low-consistency refiner, a screening device, a thickening device, and a pulp storage tower that are connected in sequence. It further includes a white water tower, a condensate water tank, and a first conversion unit. The white water tower is connected to the high-consistency refiner and the first double-roll washer, and is used to inject the paper machine white water into the first double-roll washer and inject clear water into the high-consistency refiner or the first double-roll washer. The condensate water tank is connected to the high-consistency refiner and the first double-roll washer, and is used to inject condensate water into the high-consistency refiner and the first double-roll washer. The first conversion unit is arranged between the first double-roll washer and the white water tower, and is used to switch the injection of condensate water, paper machine white water, or clear water into the first double-roll washer. The CTMP system of the present invention improves the utilization rate of white water and reduces scaling.

Description

Technical Field

[0001] The present invention belongs to the technical field of papermaking equipment, and particularly relates to a chemi-thermomechanical pulp (CTMP) system. Background Art

[0002] In recent years, the pulp and paper industry has developed rapidly, and the scale of papermaking equipment has been continuously expanding. However, the pulp and paper industry is characterized by high water consumption and a large total amount of sewage discharge. How to achieve water conservation and emission reduction is a major benefit for water resource conservation and environmental protection. At present, the pulp produced by the bleached chemi-thermomechanical pulp (BCTMP) system is finally diluted to about 5.5% with white water from the paper machine in the pulp storage tower at a concentration of about 9.5%. This part of the pulp is compressed to a dryness of about 45% after passing through the wire section of the paper machine, generating a large amount of white water. Part of it is recycled to the CTMP workshop for pulp transportation and dilution, and most of it is discharged to the sewage treatment system, causing water resource pollution and waste. Since a large amount of mineral fillers are used in the paper machine production process, these fillers contain metal elements such as calcium. If the white water containing this part of metal elements directly enters the BCTMP production system, it will cause serious scaling of the equipment, which will seriously affect the normal operation of the system. Because the bleaching chemicals for CTMP use hydrogen peroxide and some other phosphorus-containing stabilizers, the bleaching reaction will produce corresponding oxalate ions, carbonate ions, etc., which will react with the metal calcium ions in the white water filler of the paper machine to produce serious scale substances such as calcium oxalate, calcium carbonate, and phosphate scale. These scalings will reduce the efficiency of washing equipment, etc. Heavy metal ions in the filler, such as iron ions, will chemically react with the bleaching agent, resulting in the consumption of chemical reagents such as bleaching agents. Therefore, it is easy to increase the consumption of chemical agents such as bleaching agents, and it will also reduce the output of pulp washing, screening, and grinding. In severe cases, it is necessary to stop the machine for several days for descaling treatment. This is a problem that occurs in many domestic paper mills when directly using the white water of the paper machine in the CTMP workshop, resulting in a low recycling rate of the white water of the paper machine. Summary of the Invention

[0003] The main technical problem to be solved by the present invention is to provide a CTMP system that can improve the utilization rate of the white water of the paper machine and reduce the influence of scaling on the CTMP system.

[0004] To solve the above technical problems, a technical solution adopted by the present invention is to provide a chemi-thermomechanical pulp (CTMP) system. The CTMP system includes a high-concentration refiner, a bleaching and washing device, a first double-roll washer, a de-aeration tank, a low-concentration refiner, a screening device, a concentrating device, and a pulp storage tower, which are connected in sequence. It further includes a white water tower, a condensate water tank, and a first conversion unit. The white water tower is connected to the high-concentration refiner and the first double-roll washer, and is used to inject paper machine white water into the first double-roll washer and inject clear water into the high-concentration refiner or the first double-roll washer. The condensate water tank is connected to the high-concentration refiner and the first double-roll washer, and is used to inject condensate water into the high-concentration refiner and the first double-roll washer. The first conversion unit is arranged between the first double-roll washer and the white water tower, and is used to switch the injection of condensate water, paper machine white water, or clear water into the first double-roll washer.

[0005] Preferably, it further includes a clear and turbid filtrate tank and a second conversion unit. The clear and turbid filtrate tank is connected to the concentrating device and is used to inject clear and turbid filtrate. The clear and turbid filtrate tank is respectively connected to the white water tower and the condensate water tank, and the water in the white water tower and the condensate water tank is injected into the clear and turbid filtrate tank. The clear and turbid filtrate tank is connected to the high-concentration refiner and is used to inject the water in the clear and turbid filtrate tank into the high-concentration refiner. The second conversion unit is arranged between the clear and turbid filtrate tank and the high-concentration refiner, and is used to switch the injection of the water in the clear and turbid filtrate tank or the condensate water in the condensate water tank into the high-concentration refiner.

[0006] Furthermore, it further includes a first filtrate tank and a third conversion unit. The first filtrate tank is connected to the first double-roll washer and is used to receive the filtrate of the first double-roll washer. The clear and turbid filtrate tank and the condensate water tank are respectively connected to the first filtrate tank, and a third conversion unit is arranged between the connection of the clear and turbid filtrate tank and the first filtrate tank, and is used to selectively inject the water in the clear and turbid filtrate tank or the condensate water in the condensate water tank into the first filtrate tank. The first filtrate tank is connected to the bleaching and washing device and is used to inject the water in the first filtrate tank into the bleaching and washing device.

[0007] Among them, the clear and turbid filtrate tank is respectively connected to the de-aeration tank and the screening device, and is used to inject the water in the clear and turbid filtrate tank into the de-aeration tank and the screening device.

[0008] Among them, the bleaching and washing device includes at least one set of repeatedly arranged and connected rinsing device and washing device. The rinsing device at the head end is connected to the high-concentration refiner, and the washing device at the tail end is connected to the washer. The rinsing device is used to inject the slurry ground by the high-concentration refiner and the bleaching agent.

[0009] Among them, the bleaching and washing device includes two sets of repeatedly arranged rinsing devices and washing devices, namely a first rinsing device, a first washing device, a second rinsing device, and a second washing device connected in sequence. The first filtrate tank is used to supply water to the first rinsing device, the first washing device, the second rinsing device, and the second washing device.

[0010] Among them, it further includes a second filtrate tank, which is connected to the second pulp washing device and is used to receive the filtrate of the second pulp washing device. The filtrate in the second pulp washing device is used to supply water to the first rinsing device and the first pulp washing device.

[0011] Among them, it includes a power extraction device, which is connected to the stock tower and is used to extract the slurry of the concentration device to the stock tower.

[0012] Among them, the concentration device is a multi-disc concentration device.

[0013] Among them, the pulp washing device is a double-roll pulp washing device.

[0014] The beneficial effects of the present invention are as follows: Different from the prior art, in the embodiment of the present invention, paper machine white water is added to the white water tower, and the white water tower is connected to the first double-roll pulp washing machine, so that the paper machine white water can be used for the first double-roll pulp washing machine. The condensate tank is connected to the first double-roll pulp washing machine and the high-concentration refiner, so that the condensate water in the condensate tank can be used for the high-concentration refiner and the first double-roll pulp washing machine to meet the requirements of high-concentration refining and pulp washing. By setting the first conversion unit, when the first double-roll pulp washing machine needs the condensate water in the condensate tank, it is controlled by the first conversion unit, so that the white water in the white water tower will not flow into the first double-roll pulp washing machine, avoiding the cross of the white water flowing into the first double-roll pulp washing machine and the condensate water. By introducing white water into the first double-roll pulp washing machine, since the chemical agents such as bleaching agents contained in the pulp after being treated by the bleaching and pulp washing device are trace amounts, the chemical agents such as bleaching agents in the pulp entering the first double-roll pulp washing machine can be ignored. When the paper machine white water enters the first double-roll pulp washing machine, no precipitation will form, which will not affect the equipment in the chemi-thermomechanical pulp, and will not have any impact on the dosage of chemical agents such as bleaching agents added in the bleaching and pulp washing device. It can improve the utilization rate of white water, which is beneficial to the conservation of water resources and the reduction of environmental pollution. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of an embodiment of the chemi-thermomechanical pulp of the present invention. Detailed Embodiments

[0016] To make the purpose, technical solution and effects of the present invention clearer and more definite, the following further describes the present invention in detail with reference to the accompanying drawings and by way of examples.

[0017] The embodiment of the present invention provides a chemi-thermomechanical pulp system, as Figure 1As shown in the figure, the chemi-thermomechanical pulp (CTMP) system includes a high-concentration refiner 1, a bleaching and washing device, a first double-roll washer 6, a de-aeration tank 7, a low-concentration refiner 8, a screening device 9, a concentrating device 10, and a pulp storage tower 11, which are connected in sequence; it also includes a white water tower 12, a condensate water tank 13, and a first conversion unit 20. The white water tower 12 is connected to the high-concentration refiner 1 and the first double-roll washer 6, and is used to inject paper machine white water into the first double-roll washer 6 and inject clear water into the high-concentration refiner 1 or the first double-roll washer 6; the condensate water tank 13 is connected to the high-concentration refiner 1 and the first double-roll washer 6, and is used to inject condensate water into the high-concentration refiner 1 and the first double-roll washer 6; the first conversion unit 20 is arranged between the first double-roll washer 6 and the white water tower 12, and is used to switch the injection of condensate water, paper machine white water, or clear water into the first double-roll washer 6.

[0018] In the embodiment of the present invention, by adding paper machine white water to the white water tower 12 and connecting the white water tower 12 to the first double-roll washer 6, the paper machine white water can be used for the first double-roll washer 6. The condensate water tank 13 is connected to the first double-roll washer 6 and the high-concentration refiner 1, so that the condensate water in the condensate water tank 13 can be used for the high-concentration refiner 1 and the first double-roll washer 6 to meet the requirements of high-concentration refining and washing; by setting the first conversion unit 20, when the first double-roll washer 6 needs the condensate water in the condensate water tank 13, through the control of the first conversion unit 20, the white water in the white water tower 12 will not flow into the first double-roll washer 6, avoiding the cross of the white water flowing into the first double-roll washer 6 and the condensate water; by introducing white water into the first double-roll washer 6, since the chemical agents such as bleaching agents contained in the pulp after being treated by the bleaching and washing device are trace amounts, the chemical agents such as bleaching agents in the pulp entering the first double-roll washer 6 can be ignored. When the paper machine white water enters the first double-roll washer 6, no precipitation will form, which will not affect the equipment in the CTMP system and will not have any impact on the dosage of chemical agents such as bleaching agents added in the bleaching and washing device. It can improve the utilization rate of white water, which is beneficial to the conservation of water resources and the reduction of environmental pollution.

[0019] Among them, Figure 1 The arrow direction in the figure is the flow direction of water or slurry, or the direction of adding chemical agents such as bleaching agents.

[0020] Among them, the concentrating device 10 in the embodiment of the present invention is a multi-tray concentrating device 10. In other embodiments, the concentrating device 10 can also be other types of concentrating devices 10, and the present invention does not make specific limitations.

[0021] As a preferred embodiment, the refiner pulp system in the embodiments of the present invention further includes a clear and turbid filtrate tank 14 and a second conversion unit 21. The clear and turbid filtrate tank 14 is connected to the concentration device 10 and is used for injecting clear and turbid filtrate. The clear and turbid filtrate tank 14 is respectively connected to a white water tower 12 and a condensate tank 13, and the water in the white water tower 12 and the condensate tank 13 is injected into the clear and turbid filtrate tank 14. The clear and turbid filtrate tank 14 is connected to a high-concentration refiner 1 and is used for injecting the water in the clear and turbid filtrate tank 14 into the high-concentration refiner 1. The second conversion unit 21 is arranged between the clear and turbid filtrate tank 14 and the high-concentration refiner 1 and is used for switching the water in the clear and turbid filtrate tank 14 or the condensate water in the condensate tank 13 injected into the high-concentration refiner 1. By setting the clear and turbid filtrate tank 14 and the second conversion unit 21 in the embodiments of the present invention, the clear and turbid filtrate tank 14 can collect the clear and turbid liquid filtered out by the concentration device 10, and the clear and turbid liquid can be further recycled to the high-concentration refiner 1 equipment and subsequent equipment. The clear and turbid filtrate tank 14 is connected to the white water tower 12 and the condensate tank 13, and white water, clear water and condensate water can be injected, and the water can be applied to other equipment, which can save the distance of the pipeline. By setting the second conversion unit 21, when the white water in the white water tower 12 is injected into the clear and turbid filtrate tank 14, the second conversion unit 21 makes the clear and turbid filtrate tank 14 not communicate with the high-concentration refiner 1, avoiding the introduction of white water into the high-concentration refiner 1, thereby causing the inflow of white water to be introduced into the bleaching and washing pulp device.

[0022] The clear and turbid filtrate tank 14 in the embodiments of the present invention is also connected to a submergence tank 7 and a screening device 9 and is used for providing the water in the clear and turbid filtrate tank 14 to the submergence tank 7 and the screening device 9. Since the amount of chemical agents such as bleaching agents introduced into the submergence tank 7, the low-concentration refiner 8 and the screening device 9 is very small, the utilization rate of white water can be increased by using white water, and almost no calcium carbonate precipitation will be formed, avoiding fouling of the submergence tank 7, the low-concentration refiner 8, the screening device 9 and the concentration device 10.

[0023] Further, it further includes a first filtrate tank 15 and a third conversion unit 22. The first filtrate tank 15 is connected to the first double-roll pulp washer 6 and is used to receive the filtrate of the first double-roll pulp washer 6. The clear and turbid filtrate tank 14 and the condensate tank 13 are respectively connected to the first filtrate tank 15, and a third conversion unit 22 is arranged between the connection of the clear and turbid filtrate tank 14 and the first filtrate tank 15, which is used to selectively inject the water in the clear and turbid filtrate tank 14 or the condensate water into the first filtrate tank 15. The first filtrate tank 15 is connected to the bleaching and washing pulp device and is used to inject the water in the first filtrate tank 15 into the bleaching and washing pulp device. By providing the first filtrate tank 15, the filtrate water of the first double-roll pulp washer 6 can be received and used for the bleaching and washing pulp device. Among them, the first filtrate tank 15 is connected to the clear and turbid filtrate tank 14, and the water in the clear and turbid filtrate tank 14 can be injected into the first filtrate tank 15 for use in the bleaching and washing pulp device. Since white water from the paper machine is introduced into the clear and turbid filtrate tank 14, by providing the third conversion unit 22, when white water from the paper machine is introduced into the clear and turbid filtrate tank 14, the third conversion unit 22 works, so that the clear and turbid filtrate tank 14 cannot flow into the first filtrate tank 15, avoiding flowing into the paper bleaching and washing pulp device from the first filtrate tank 15. Among them, the condensate tank 13 is connected to the first filtrate tank 15 and can be used to provide condensate water to the first filtrate tank 15.

[0024] In the embodiment of the present invention, the first conversion unit 20, the second conversion unit 21 and the third conversion unit 22 can be valves.

[0025] Among them, the bleaching and washing pulp device includes at least one set of repeatedly arranged and connected rinsing device and washing pulp device. The rinsing device at the head end is connected to the high-concentration refiner 1, and the washing pulp device at the tail end is connected to the first double-roll pulp washer 6. The rinsing device is used to inject the slurry ground by the high-concentration refiner 1 and the bleaching agent. By providing the rinsing device and the washing pulp device in the bleaching and washing pulp device, the bleached slurry can be further washed through the washing pulp device. Among them, the washing pulp device at the tail end is connected to the first double-roll pulp washer 6. After two consecutive washing steps, the pulp reaches a better washing state, and the entry of chemical agents such as bleaching agents into subsequent stages such as the de-aeration tank 7 can be reduced.

[0026] As a preferred solution, the bleaching and pulp washing device includes two sets of repeatedly arranged rinsing devices and pulp washing devices, namely a first rinsing device 2, a first pulp washing device 3, a second rinsing device 4, and a second pulp washing device 5 that are connected in sequence. The first filtrate tank 15 is used to supply water to the first rinsing device 2, the first pulp washing device 3, the second rinsing device 4, and the second pulp washing device 5. By arranging two sets of repeatedly arranged rinsing devices and pulp washing devices, after the pulp is rinsed by the first bleaching device, to prevent the pulp from being completely bleached, after the pulp of the first rinsing device 2 is washed by the first pulp washing device 3, it is then bleached a second time, so that the pulp is bleached by the second bleaching device. Through secondary bleaching, it can ensure that the pulp is bleached more completely, improving the whiteness and uniformity of the pulp. Among them, a chemical agent adding port is provided on the pipeline between the high-concentration refiner 1 and the first rinsing device 2 or on the first rinsing device 2 for adding chemical agents such as bleaching agents; a chemical agent adding port is provided on the pipeline between the first pulp washing device 3 and the second rinsing device 4 or on the second rinsing device 4 to add chemical agents such as bleaching agents to the second rinsing device 4. In other embodiments, multiple sets of repeatedly arranged rinsing devices and pulp washing devices can also be used.

[0027] Among them, a second filtrate tank 16 and a third filtrate tank 17 are further included. The second filtrate tank 16 is connected to the second pulp washing device 5 and is used to receive the filtrate of the second pulp washing device 5. The filtrate in the second pulp washing device 5 is used to supply water to the first rinsing device 2 and the first pulp washing device 3. The third filtrate tank 17 is connected to the first pulp washing device 3 and is used to receive the filtrate of the first pulp washing device 3; the second filtrate tank 16 is connected to the first filtrate tank 15, and the water in the first filtrate tank 15 can be injected into the second filtrate tank 16 to supply the filtrate of the second pulp washing device 5, the filtrate in the first double-roll pulp washing machine 6, as well as clean water and condensed water to the first pulp washing device 3 and the first pulp washing device 3. So as to meet the water requirements at each stage in the chemi-thermomechanical pulp. Among them, the filtrate in the third filtrate tank 17 is added with an alkaline reagent for recovery and evaporation.

[0028] Among them, a power extraction device 18 is included. The power extraction device 18 is connected to the stock pulp tower 11 and is used to extract the slurry of the concentration device 10 to the stock pulp tower 11. The pulp stored in the stock pulp tower 11 is used to introduce pulp into the paper machine. Further, a power extraction device 18 can also be provided between the concentration device 10 and the stock pulp tower 11, and a riser pipe 19 is provided between the concentration device 10 and the extraction device 18 to facilitate the extraction device 18 to extract the pulp in the concentration device 10 to the stock pulp tower 11. Among them, the extraction device 18 is a power pump.

[0029] Among them, the pulp washing device in the embodiment of the present invention is a double-roll pulp washing device. The first pulp washing device 3 and the second pulp washing device 5 are respectively a first double-roll pulp washing device and a second double-roll pulp washing device.

[0030] In the embodiment of the present invention, by providing a pipeline 24, the white water of the paper machine can be injected into the white water tower 12; by means of a pipeline 25, the condensate water tank 13 is connected to the clear and turbid filtrate tank 14 and the pipelines are shared to flow to the high-concentration refiner 1; by providing a pipeline 26, the condensate water tank 13 can be communicated with the first double-roll pulp washer 6, and by providing a pipeline 27, the condensate water tank 13 can be communicated with the first filtrate tank 15.

[0031] The main working process and principle of the chemi-thermomechanical pulp system in the embodiment of the present invention are as follows:

[0032] After being pretreated, the wood chips enter the high-concentration refiner 1 for high-concentration refining. After high-concentration refining, the wood chips become pulp with a freeness of about 700 ML and a dry pulp content of about 40%. Then, hydrogen peroxide, NAOH, DTPA and a stabilizer bleaching chemical are added, and at the same time, the filtrate extruded by the second pulp washer 5 is injected into the first rinsing device 2 for dilution. The pulp diluted to a concentration of 12% enters the first rinsing device 2 for medium-concentration bleaching, which is the first-stage bleaching.

[0033] After the first-stage bleaching in the first rinsing device 2 is completed, the filtrate of the second pulp washer 5 in the second filtrate tank 16 is added to the bottom of the first rinsing device 2 to dilute the slurry in the first rinsing device 2 to a concentration of 9.5%; it enters the first pulp washer 3 for extrusion pulp washing to reduce COD, and all the black liquor waste liquid generated by the first pulp washer 3 is sent to the alkali recovery for evaporation treatment.

[0034] After the pulp is washed by the first pulp washer 3, hydrogen peroxide, NAOH, DTPA and a stabilizer bleaching chemical are added again and the pulp enters the second rinsing device 4 for high-concentration bleaching. After the bleaching is completed, the pulp is diluted with the filtrate in the first filtrate tank 15 at the rear stage, and then enters the second pulp washer 5 for washing.

[0035] The slurry enters the last-stage first double-roll pulp washer 6 and all uses clean condensate water for dilution pulp washing. At this time, the first conversion unit 20 works, so that the water in the white water tower 12 cannot flow into the first double-roll pulp washer 6. After the pulp is washed by the first double-roll pulp washer 6, the pulp is diluted at low concentration with the white water entering the clear and turbid filtrate tank 14 system through the white water tower 12 or the white water in the white water tower 12; then it enters the submergence tank 7 for submergence treatment.

[0036] After the latent elimination treatment is completed, the pulp enters the low-concentration pulping machine 8 for low-concentration grinding treatment. When the pulp is free and reduced to the required level, the pulp enters the screening device 9 for screening and purification. The concentration of the good pulp after screening is about 2.2%. Then the pulp is concentrated to 9.5% by the concentration device 10 and then sent to the pulp storage tower 11 for use by the paper machine. When the paper machine is used, it is diluted to 5.5% concentration with paper machine white water and sent to the paper machine system. The white water generated after the pulp is compressed to 45% dryness in the paper machine wire after a system treatment is the paper machine white water.

[0037] In the chemical-mechanical pulping system of the embodiment of the present invention, white water is isolated at the first double-roller pulp washer 6 stage. After the pulp is washed by the second pulp washer 5 and the first double-roller pulp washer, the COD and hydrogen peroxide residue of the pulp have been reduced to the lowest value. In the subsequent low-concentration pulper 8, the screening device 9 and the concentrating device 10, only the paper machine white water is used for simple dilution and other mechanical and physical effects, and at the same time, the filler metal substances contained in the paper machine white water are prevented from entering the front-stage pulp washing, bleaching, and high-concentration pulping to produce complex chemical reactions, effectively avoiding the production of scaling substances such as calcium oxalate and calcium carbonate on the surface of the equipment, and ensuring the normal and stable operation of various system equipment. At the same time, after the first double-roller pulp washer 6, the pulp is effectively recycled in large quantities with the paper machine white water for various dilutions, thereby greatly reducing the amount of clean water, of which the amount of clean water saved is about 5.9 tons per ton of air-dried pulp.

[0038] The above description is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A chemi-thermomechanical pulp system, characterized in that, the chemi-thermomechanical pulp system comprises a high-consistency refiner, a bleaching and washing device, a first double-roll washer, a de-aeration tank, a low-consistency refiner, a screening device, a concentrating device and a pulp storage tower which are connected in sequence; further comprising: a white water tower, which is connected to the high-consistency refiner and the first double-roll washer, and is used for injecting paper machine white water into the first double-roll washer and injecting clear water into the high-consistency refiner or the first double-roll washer; a condensate water tank, which is connected to the high-consistency refiner and the first double-roll washer, and is used for injecting condensate water into the high-consistency refiner and the first double-roll washer; a first conversion unit, which is arranged between the first double-roll washer and the white water tower, and is used for switching the injection of condensate water, paper machine white water or clear water into the first double-roll washer; a clear and turbid filtrate tank and a second conversion unit, the clear and turbid filtrate tank is connected to the concentrating device and is used for injecting clear and turbid filtrate; the clear and turbid filtrate tank is respectively connected to the white water tower and the condensate water tank, and the water in the white water tower and the condensate water tank is injected into the clear and turbid filtrate tank; the clear and turbid filtrate tank is connected to the high-consistency refiner and is used for injecting the water in the clear and turbid filtrate tank into the high-consistency refiner, and the second conversion unit is arranged between the clear and turbid filtrate tank and the high-consistency refiner and is used for switching the injection of the water in the clear and turbid filtrate tank or the condensate water in the condensate water tank into the high-consistency refiner.

2. The chemi-thermomechanical pulp system according to claim 1, characterized in that, further comprising a first filtrate tank and a third conversion unit, the first filtrate tank is connected to the first double-roll washer and is used for receiving the filtrate of the first double-roll washer; the clear and turbid filtrate tank and the condensate water tank are respectively connected to the first filtrate tank, and a third conversion unit is arranged between the connection of the clear and turbid filtrate tank and the first filtrate tank for selectively injecting the water in the clear and turbid filtrate tank or the condensate water in the condensate water tank into the first filtrate tank; the first filtrate tank is connected to the bleaching and washing device and is used for injecting the water in the first filtrate tank into the bleaching and washing device.

3. The chemi-thermomechanical pulp system according to claim 2, characterized in that, the clear and turbid filtrate tank is respectively connected to the de-aeration tank and the screening device and is used for injecting the water in the clear and turbid filtrate tank into the de-aeration tank and the screening device.

4. The chemi-thermomechanical pulp system according to claim 2, characterized in that, the bleaching and washing device comprises at least one set of repeatedly arranged and connected rinsing device and washing device, wherein the rinsing device at the head end is connected to the high-consistency refiner, the washing device at the tail end is connected to the first double-roll washer, and the rinsing device is used for injecting the slurry ground by the high-consistency refiner and the bleaching agent.

5. The chemi-thermomechanical pulp system according to claim 4, characterized in that, The bleaching pulp washing device includes two sets of repeatedly arranged rinsing devices and pulp washing devices, namely a first rinsing device, a first pulp washing device, a second rinsing device, and a second pulp washing device connected in sequence. The first filtrate tank is used to supply water to the first rinsing device, the first pulp washing device, the second rinsing device, and the second pulp washing device.

6. The chemi-thermomechanical pulp system according to claim 5, wherein, it further includes a second filtrate tank. The second filtrate tank is connected to the second pulp washing device and is used to receive the filtrate of the second pulp washing device. The filtrate in the second pulp washing device is used to supply water to the first rinsing device and the first pulp washing device.

7. The chemi-thermomechanical pulp system according to claim 1, wherein, it includes a power extraction device. The power extraction device is connected to the stock pulp tower and is used to extract the pulp slurry of the concentration device to the stock pulp tower.

8. The chemi-thermomechanical pulp system according to claim 1, wherein, the concentration device is a multi-disc concentration device.

9. The chemi-thermomechanical pulp system according to claim 4, wherein, the pulp washing device is a double-roll pulp washing device.

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