Efficient energy-saving washing system and method for PAN precursor

Abstract

The invention relates to a high-efficiency energy-saving washing system and method for PAN (Polyacrylonitrile) precursors, which are used for solving the problems of high water drawing cost and low temperature control precision of the existing washing. The device comprises a heat preservation storage tank device, a heat exchange device and a water traction washing tank device. The drying condensate water sequentially passes through a PAN precursor washing system composed of a heat preservation storage tank device, a heat exchange device and a water drawing washing tank device, precise temperature control of washing water drawing is achieved, the water drawing temperature variation range is controlled within 1 DEG C, and the washing temperature variation range is controlled within 0.9 DEG C. The drying condensate water is recycled, the energy loss is reduced, the washing efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon fiber manufacturing, and particularly relates to a high-efficiency and energy-saving water-washing system and method for PAN precursor. Background Art

[0002] Carbon fiber is a polymer fiber material with a carbon content of more than 90%. It has the characteristics of high strength, high modulus, acid and alkali resistance, corrosion resistance, etc. It is widely used in aerospace, transportation rails, new energy and other fields, and is an important material basis for the development of the national economy. The tensile strength of high-strength and high-modulus carbon fiber exceeds 7000MPa, and the elastic modulus exceeds 350GPa. It has ultra-high stiffness, excellent specific modulus, good environmental stability and dimensional stability. The production process of PAN carbon fiber goes through polymerization, spinning, heat treatment, carbonization and other processes. However, the production cost of the precursor accounts for 50-60% of the total cost of carbon fiber. Reducing the waste of dimethyl sulfoxide (DMSO) solvent requires advanced water washing and water pulling processes to reduce the DMSO content inside the precursor.

[0003] The traditional PAN raw silk washing device adopts a flow-inhibiting multi-stage washing method, which injects hot desalted water into the water drawing tank and uses potential energy to achieve automatic flow of desalted water. This method is simple and efficient, but it is difficult to achieve precise control of the washing and water drawing temperature, and the water consumption is huge, resulting in high cost losses. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a high-efficiency and energy-saving water-washing system and method for PAN raw silk. The device recycles and utilizes drying condensed water, relies on a heat exchanger to achieve precise temperature control of each level of water-drawing washing tank, reduces energy loss, improves water washing effect, and reduces production costs.

[0005] The technical solution for achieving the purpose of the present invention is as follows:

[0006] A PAN raw yarn high-efficiency and energy-saving water washing system, comprising a heat preservation storage tank device, a heat exchange device and a water-drawing water washing tank device;

[0007] The heat preservation tank device includes a flow meter, a pneumatic valve, a thermometer, a liquid level meter, and a heat preservation tank 1 and a heat preservation tank 2;

[0008] The drying condensate water pipeline is connected to the insulation storage tank 1 and the insulation storage tank 2, and a flow meter and a pneumatic valve are provided on the drying condensate water pipeline;

[0009] The thermometer and liquid level gauge are provided on the thermal insulation storage tank;

[0010] The heat preservation storage tank is connected to a heat exchange device;

[0011] The heat exchange device includes a heat exchanger, a pressure gauge, a motor pump and a pneumatic valve;

[0012] The pipelines connecting the first and second heat preservation storage tanks to the corresponding heat exchangers are provided with motor pumps and are connected with pressure gauges;

[0013] The heat exchange device is connected to the water-drawn water-washing tank device;

[0014] The water-drawn water-washing tank device comprises a water-washing tank, a water-drawn tank and a temperature sensor;

[0015] A heat exchanger corresponding to the heat preservation storage tank is connected to a water draw tank, and a temperature sensor is arranged on the water draw tank;

[0016] The water draw tank is connected to the second heat preservation storage tank through a pipeline, and the second heat preservation storage tank is provided with a thermometer and a liquid level gauge;

[0017] The heat exchanger corresponding to the second insulation storage tank is connected to a water washing tank, and a temperature sensor is arranged on the water washing tank.

[0018] A condensate inlet is connected to the top of the heat exchanger, and a return water outlet is connected to the bottom of the heat exchanger.

[0019] Compared with the prior art, the beneficial effects of the present invention are: (1) providing a high-efficiency and energy-saving water-washing system and method for PAN raw silk, realizing the recycling of drying condensed water and reducing energy loss; (2) the device realizes precise temperature control of water washing and water drawing, the water drawing temperature variation range is controlled within 1°C, and the water washing temperature variation range is controlled within 0.9°C, thereby improving water washing efficiency and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the PAN raw silk high-efficiency and energy-saving water washing system.

[0021] 1. Flow meter; 2. Pneumatic valve; 3. Thermometer; 4. Liquid level gauge; 5. Storage tank one; 6. Pressure gauge; 7. Pump; 8. Water trough; 9. Temperature sensor; 10. Storage tank two; 11. Water washing tank; 12. Heat exchanger. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0023] A PAN raw yarn high-efficiency and energy-saving water washing system, comprising a heat preservation storage tank device, a heat exchange device and a water-drawing water washing tank device;

[0024] The heat preservation tank device includes a flow meter 1, a pneumatic valve 2, a thermometer 3, a liquid level meter 4, a heat preservation tank 1 5, and a heat preservation tank 2 10;

[0025] The drying condensed water pipeline is connected to the insulation storage tank 1 5 and the insulation storage tank 2 10, and a flow meter 1 and a pneumatic valve 2 are provided on the drying condensed water pipeline;

[0026] A thermometer 3 and a liquid level gauge 4 are provided on the heat preservation storage tank 5;

[0027] The heat preservation storage tank 15 is connected to the heat exchange device;

[0028] The heat exchange device includes a heat exchanger 12, a pressure gauge 6, a motor pump 7 and a pneumatic valve 2;

[0029] The pipelines connecting the heat preservation storage tank 1 5 and the heat preservation storage tank 2 10 to the corresponding heat exchanger 12 are provided with a motor pump 7 and connected with a pressure gauge 6;

[0030] The heat exchange device is connected to the water-drawn water-washing tank device;

[0031] The water-drawn washing tank device comprises a washing tank 11, a water-drawn tank 8 and a temperature sensor 9;

[0032] The heat exchanger 12 corresponding to the heat preservation storage tank 1 5 is connected to the water draw tank 8, and a temperature sensor 9 is arranged on the water draw tank 8;

[0033] The water draw tank 8 is connected to the second heat preservation storage tank 10 through a pipeline, and the second heat preservation storage tank 10 is provided with a thermometer 3 and a liquid level gauge 4;

[0034] The heat exchanger 12 corresponding to the second heat preservation storage tank 10 is connected to the water washing tank 11, and the temperature sensor 9 is arranged on the water washing tank 11.

[0035] The top end of the heat exchanger 12 is connected to a condensed water inlet, and the bottom end is connected to a return water outlet.

[0036] The heat preservation storage tank 1 5 is also connected to the heat preservation storage tank 2 10 via the motor pump 7, and a corresponding pneumatic valve 2 is provided on the pipeline therebetween.

[0037] The heat preservation storage tank 2 10 is also directly connected to the waste storage tank via the motor pump 7.

[0038] A method based on the above-mentioned PAN raw yarn high-efficiency and energy-saving water washing system, characterized in that:

[0039] The method includes a PAN raw silk water washing system composed of a heat preservation tank device, a heat exchange device and a water-drawing water washing tank device, through which the dried condensed water sequentially passes; the dried condensed water enters the two-stage water-drawing system from the inlet end, passes through each level of the water washing system sequentially, and the dried condensed water leaves the multi-stage water washing system from the end of the last level of the water washing tank, and the dried condensed water is led from the outlet end of each level of the water-drawing water washing device to the fluid inlet end of the next level of the dried condensed water washing device. The dried condensed water is first stored in the heat preservation tank 1 5, and then injected into the heat exchanger 12 through the motor pump 7, and then injected into the water-drawing tank 8 after heat exchange with chilled water to control the required temperature and flow, and then injected into the heat preservation tank 2 10 through the motor pump 7 at the same time; the dried condensed water in the heat preservation tank 2 10 is injected into the heat exchanger through the motor pump 7, and then injected into the water washing tank 11 after heat exchange with chilled water to control the required temperature and flow, and then passes through each level of the water washing system sequentially.

[0040] Specifically, the drying condensate water temperature is 80-84°C. The drying condensate water flow rate is 900-1200L / h. The heat exchange efficiency of the heat exchange device is 50-80%; the cooling water temperature of the heat exchange device is 18-25°C; the cooling water flow rate of the heat exchange device is 1500-2200L / h. The water tank flow rate is 900-1200L / h; the water tank temperature is 68-72°C. The water washing tank flow rate is 900-1200L / h; the water washing tank temperature is 32-38°C.

[0041] Example 1

[0042] A PAN raw silk high-efficiency energy-saving water washing system is carried out as follows

[0043] The drying condensate water temperature is 82°C; the flow rate is 900L / h;

[0044] The dried condensed water is injected from the heat preservation storage tank 15 into the heat exchanger through the pipeline, motor pump and pressure gauge;

[0045] The heat exchange efficiency of the heat exchanger is 70%;

[0046] The dried condensate is injected into the water-drawn washing tank through the pipeline from the heat exchanger;

[0047] Chilled water 1 passes through the heat exchanger to the return water pipe; the temperature of cooling water 1 is 21.3℃;

[0048] Cooling water 1 flow rate is 908L / h; water flow rate is 900L / h; water temperature is 70±1℃;

[0049] The dried condensed water is injected from the water tank through the pipeline into the heat preservation storage tank 210;

[0050] The drying condensed water sequentially passes through the PAN raw yarn washing system consisting of a heat preservation tank device, a heat exchange device and a water-drawing washing tank device;

[0051] The dried condensed water enters the two-stage water traction system from the inlet tank, and passes through each level of water washing system in turn.

[0052] The dried condensed water leaves the multi-stage washing system from the end of the last washing tank;

[0053] The dried condensed water is led from the outlet tank end of each stage of water-drawing and water-washing device to the fluid inlet tank end of the next stage of dried condensed water-washing device;

[0054] The flow rate of cooling water 2 is 2121L / h;

[0055] The water washing temperature is 36±0.9℃; the water washing flow rate is 904L / h.

[0056] Table 1 Experimental parameters and water-drawn washing temperature of the experimental example

[0057]

[0058] It can be seen from the above table that the present invention can reduce the washing water temperature and save costs.

Claims

1. A PAN raw yarn high-efficiency and energy-saving water washing system, characterized in that: It includes a heat preservation storage tank device, a heat exchange device and a water-drawn water washing tank device; The heat-insulating storage tank device comprises a flow meter (1), a pneumatic valve (2), a thermometer (3), a liquid level meter (4), a heat-insulating storage tank 1 (5), and a heat-insulating storage tank 2 (10); The drying condensed water pipeline is connected to the insulation storage tank 1 (5) and the insulation storage tank 2 (10), and a flow meter (1) and a pneumatic valve (2) are provided on the drying condensed water pipeline; The first heat-insulating storage tank (5) is provided with a thermometer (3) and a liquid level gauge (4); The heat-insulating storage tank one (5) is connected to a heat exchange device; The heat exchange device comprises a heat exchanger (12), a pressure gauge (6), a motor pump (7) and a pneumatic valve (2); The pipelines connecting the heat preservation storage tank 1 (5) and the heat preservation storage tank 2 (10) to the corresponding heat exchanger (12) are provided with a motor pump (7) and are connected to a pressure gauge (6); The heat exchange device is connected to the water-drawn water-washing tank device; The water-drawn washing tank device comprises a water washing tank (11), a water-drawn tank (8) and a temperature sensor (9); The heat exchanger (12) corresponding to the heat preservation storage tank 1 (5) is connected to the water draw groove (8), and a temperature sensor (9) is arranged on the water draw groove (8); The water trough (8) is connected to the second heat preservation storage tank (10) through a pipeline, and the second heat preservation storage tank (10) is provided with a thermometer (3) and a liquid level gauge (4); The heat exchanger (12) corresponding to the second heat preservation storage tank (10) is connected to the water washing tank (11), and a temperature sensor (9) is arranged on the water washing tank (11). The top end of the heat exchanger (12) is connected to a condensate water inlet, and the bottom end is connected to a return water outlet.

2. The PAN raw yarn high-efficiency and energy-saving water washing system according to claim 1 is characterized in that: The heat preservation storage tank 1 (5) is also connected to the heat preservation storage tank 2 (10) via a motor pump (7), and a corresponding pneumatic valve (2) is provided on the pipeline therebetween.

3. The PAN raw yarn high-efficiency and energy-saving water washing system according to claim 1 is characterized in that: The second heat preservation storage tank (10) is also directly connected to the waste storage tank via the motor pump (7).

4. A method for the PAN raw yarn high-efficiency and energy-saving water washing system based on any one of claims 1 to 3, characterized in that: The method includes The drying condensed water sequentially passes through the PAN raw yarn washing system consisting of a heat preservation tank device, a heat exchange device and a water-drawing washing tank device; The dried condensed water enters the two-stage water traction system from the inlet tank, and passes through each level of water washing system in turn. The dried condensed water leaves the multi-stage water washing system from the end of the last water washing tank. The dried condensed water is led from the outlet tank end of each stage of water-drawn water washing device to the fluid inlet tank end of the next stage of dried condensed water washing device. The dried condensed water is first stored in the insulation storage tank 1 (5), and then injected into the heat exchanger (12) through the motor pump (7), and then injected into the water draw tank (8) after heat exchange with the chilled water to control the required temperature and flow rate, and then injected into the insulation storage tank 2 (10) through the motor pump (7); the dried condensed water in the insulation storage tank 2 (10) is injected into the heat exchanger through the motor pump (7), and then injected into the water washing tank (11) after heat exchange with the chilled water to control the required temperature and flow rate, and then passes through each level of water washing system in sequence.

5. The high-efficiency and energy-saving water washing method for PAN raw yarn according to claim 4, characterized in that: The drying condensed water temperature is 80-84°C. The drying condensed water flow rate is 900-1200L / h.

6. The high-efficiency and energy-saving water washing method for PAN raw yarn according to claim 4, characterized in that: The heat exchange device has a heat exchange efficiency of 50-80%; the cooling water temperature of the heat exchange device is 18-25°C; and the cooling water flow rate of the heat exchange device is 1500-2200L / h.

7. The high-efficiency and energy-saving water washing method for PAN raw yarn according to claim 4, characterized in that: The water flow rate of the water tank is 900-1200L / h; the water temperature of the water tank is 68-72℃.

8. The high-efficiency and energy-saving water washing method for PAN raw yarn according to claim 4, characterized in that: The flow rate of the water washing tank is 900-1200L / h; the temperature of the water washing tank is 32-38℃.

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