Ammoniation system for polyacrylonitrile spinning solution
By designing an ammonia system including ammonia cylinder insulation device, weight sensor, ammonia regulating valve, pressure sensor, check valve, ammonia distributor and static mixer, the ammonia gas in the spinning raw liquid ammonia system is solved The problem of bottle frosting and uniform mixing ammonia with the stock solution achieves a stable and efficient ammonia process.
Patent Information
- Application Number
- CN202411638255.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-16
- Publication Date
- 2025-02-18
AI Technical Summary
In the prior art, the ammonia ammonia system is prone to frosting of ammonia cylinders during the ammonia addition process, resulting in reduced ammonia vaporization, pressure fluctuations, and even stops the ammonia supply, and the uniform mixing of ammonia and spinning liquid. problem.
An ammonization system including an ammonia cylinder insulation device, a weight sensor, an ammonia regulating valve, a pressure sensor, a check valve, an ammonia distributor and a static mixer are designed. The ammonia cylinder is prevented from frosting through the insulation device, the weight sensor accurately measures the rate of ammonia addition, and the ammonia distributor and static mixer ensure uniform contact and mixing of ammonia with the stock solution.
It effectively solves the problem of frosting in ammonia cylinders, stabilizes the vaporization of ammonia, ensures uniform mixing of ammonia and spinning raw liquid, and improves the quality of the raw silk.
Smart Images
Figure CN119462986A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of ammoniazing of spinning solution in the carbon fiber industry, and particularly relates to an ammoniazing system for a polyacrylonitrile-based carbon fiber spinning solution. Background Art
[0002] Polyacrylonitrile-based carbon fiber is a high-performance fiber material with excellent properties such as high specific strength, high specific modulus, low density, and chemical stability. It is widely used in aerospace, automobile, sports equipment and other fields.
[0003] The quality of the precursor is the key to determining the various properties of carbon fiber. A large part of the defects in the precursor comes from the coagulation bath. The skin-core structure and macropores produced in the coagulation bath are important factors affecting the performance of carbon fiber.
[0004] After the spinning solution is aminated, the hydrophilicity of the spinning solution can be improved. In the coagulation bath stage, the skin-core structure and macropores can be well reduced, which is helpful to obtain high-quality raw silk. At present, the system for ammoniation of spinning solution has the problem of frosting of ammonia cylinders during the ammonia addition process. Frosting of ammonia cylinders can easily lead to a series of problems, such as reduced ammonia vaporization, pressure fluctuations on the ammonia pipeline, and even cessation of vaporization and ammonia supply, reflux of the solution or blockage of the ammonia pipeline. In addition, since the viscosity of the solution is generally relatively large, the uniform mixing of ammonia and spinning solution is also a major problem in ammonia. Summary of the invention
[0005] The present invention mainly solves the technical problems existing in the above-mentioned prior art and provides an ammoniaizing system for polyacrylonitrile spinning stock solution.
[0006] The above technical problems of the present invention are mainly solved by the following technical solutions: an ammoniation system for polyacrylonitrile spinning stock solution. In order to solve the above problems, the present invention provides an ammoniation system for polyacrylonitrile spinning stock solution, comprising: an ammonia bottle insulation device, the outside of which is open insulation cotton, and the insulation cotton is tightened and loosened with Velcro; a rubber heating pipe is installed inside, and the heating pipe is arranged on the insulation cotton in a dense lower part and sparse upper part, and hot water is passed through the heating pipe for insulation; a hot water regulating valve is provided on the hot water pipe in the inlet of the device, and a temperature sensor is provided at the lower part of the ammonia bottle side, and the temperature sensor transmits the temperature signal of the ammonia bottle to the PLC module remotely, and the PLC module controls the valve opening of the hot water regulating valve to achieve the temperature stability of the lower part of the ammonia bottle side;
[0007] Weight sensor and ammonia regulating valve. The weight sensor is placed on the lower side of the ammonia cylinder. There is an ammonia regulating valve on the ammonia pipeline. The weight sensor transmits the weight signal of the ammonia cylinder and its accessories to the PLC module at all times. The PLC converts the weight signal into a weight loss signal per unit time, that is, a mass flow signal. Then, the valve flux of the ammonia regulating valve is controlled by the PLC module to achieve the purpose of controlling the speed of ammonia addition.
[0008] Pressure sensor, check valve. The pressure sensor is mainly used to detect the pressure value on the ammonia pipeline and the spinning solution pipeline. The check valve prevents the spinning solution on the solution pipeline from flowing to the ammonia pipeline.
[0009] The ammonia distributor is a short flange tube with a jacket. Holes of the same size are evenly distributed on the inner tube of the jacket. The center of the outer tube of the short tube is connected to the ammonia pipeline to increase the contact area between ammonia and spinning solution, so as to achieve the purpose of uniform contact between ammonia and the solution. The flange on the ammonia distributor is connected to the flange on the main pipeline with bolts, and the flange on the ammonia pipeline is connected to the check valve with bolts. The ammonia distributor can be disassembled and cleaned at any time.
[0010] Static mixer: After ammonia and spinning solution are mixed, they are further mixed in the static mixer to achieve the purpose of uniform mixing of ammonia and spinning solution.
[0011] Preferably, in the above-mentioned ammoniation system, the said ammoniation system is used in any process after polymerization and before spinning; the viscosity of the spinning solution from the upstream side is ≤150,000 cP.
[0012] Preferably, in the above-mentioned ammoniation system, the ammonia cylinder and its accompanying ammonia cylinder insulation device, temperature sensor, weight sensor, hot water regulating valve, and pressure reducing valve are all in a one-in-one-standby form. When the ammonia cylinder weight sensor detects that the weight is no longer changing, it immediately switches to the standby ammonia cylinder to provide ammonia to ensure the continuity of the system.
[0013] Preferably, in the above-mentioned ammoniation system, the temperature below the side of the ammonia cylinder is ≤30°C and the temperature of the hot water in the heating pipe is ≤35°C.
[0014] Preferably, in the above-mentioned ammoniation system, the pressure measured on the ammonia pipeline is greater than the pressure measured on the raw liquid pipeline.
[0015] Preferably, in the above-mentioned ammoniation system, the hot water of the ammonia cylinder insulation device enters from the bottom and exits from the top, the heating pipes at the bottom are dense and the heating pipes at the top are relatively sparse.
[0016] Preferably, in the above-mentioned ammoniation system, the weight sensor has an accuracy of more than 0.01g and a measuring range of more than 500kg. The PLC continuously receives the weight signal and converts it into a mass flow signal of weight loss per unit time, such as 2.5kg / h. The converted mass flow signal is interlocked with the ammonia regulating valve to adjust the flow of ammonia according to the production capacity of the production line.
[0017] Preferably, in the above-mentioned ammoniation system, the ammonia distributor is connected to the main pipeline and the ammonia pipeline by flanges and can be disassembled and cleaned in time.
[0018] Preferably, in the above-mentioned ammoniation system, the static mixer is a combination of SX type and SK type.
[0019] The present invention has the following beneficial effects: it solves the problem of frost on the bottom of an ammonia bottle due to heat absorption during ammonia vaporization, and controls the temperature to make the vaporization of the ammonia bottle more stable; the ammonia addition speed is measured by a weight loss method, so that the measurement is more precise and the amount of ammonia added is more accurate; the ammonia distributor makes the ammonia addition more uniform, and can be quickly disassembled and cleaned when not used for a long time. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The present invention is a schematic diagram of the process of the ammoniation system of the polyacrylonitrile spinning solution.
[0021] In the figure: 1. weight sensor LT1; 2. temperature sensor TT1; 3. hot water regulating valve TV1; 4. ammonia cylinder; 5. ammonia cylinder outlet pressure reducing valve; 6. ammonia cylinder insulation device; 7. weight sensor LT2; 8. temperature sensor TT2; 9. hot water regulating valve TV2; 10. spare ammonia cylinder; 11. spare ammonia cylinder outlet pressure reducing valve; 12. ammonia regulating valve LV1; 13. pressure sensor PT1; 14. check valve; 15. ammonia distributor; 16. pressure sensor PT2; 17. static mixer. DETAILED DESCRIPTION
[0022] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.
[0023] It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0024] Example 1
[0025] Please refer to Figure 1 This embodiment provides an ammonia system for polyacrylonitrile spinning stock solution. The viscosity of the polyacrylonitrile spinning stock solution from the upstream side is 150,000 cP, the pressure sensor PT2 is 0.7 MPa, and the insulation device of the ammonia cylinder is passed with 35°C hot water. The temperature TT1 below the side of the ammonia cylinder is set to 25°C in the PLC, and is interlocked with the hot water regulating valve TV1 through the PLC. The PLC automatically adjusts the valve opening of TV1 to stably control the temperature of the ammonia cylinder at 25°C to avoid frost on the bottom of the ammonia cylinder.
[0026] Before opening the ammonia cylinder, record the initial total weight M1 of the ammonia cylinder and its accessories, then open the ammonia cylinder and the pressure reducing valve behind it, adjust the ammonia outlet pressure to 0.8MPa, and the PLC converts the data collected by the weight sensor LT1 into mass flow data. The mass flow rate is set to 2.5kg / h in the PLC, and is interlocked with the ammonia regulating valve LV1. The PLC automatically adjusts the valve opening of LV1 to stably control the mass flow rate at 2.5kg / h.
[0027] After the ammonia passes through the check valve, the ammonia distributor evenly distributes the ammonia in the stock liquid pipeline, and then goes to the static mixer with the stock liquid for full mixing.
[0028] Example 2
[0029] Please refer to Figure 1 This embodiment provides an ammonia system for polyacrylonitrile spinning stock solution. The viscosity of the polyacrylonitrile spinning stock solution from the upstream side is 120,000 cP, the pressure sensor PT2 is 0.6 MPa, and the insulation device of the ammonia cylinder is passed with 35°C hot water. The temperature TT1 below the side of the ammonia cylinder is set to 25°C in the PLC, and is interlocked with the hot water regulating valve TV1 through the PLC. The PLC automatically adjusts the valve opening of TV1 to stably control the temperature of the ammonia cylinder at 25°C to avoid frost on the bottom of the ammonia cylinder.
[0030] Before opening the ammonia cylinder, record the initial total weight M2 of the ammonia cylinder and its accessories, then open the ammonia cylinder and the pressure reducing valve behind it, adjust the ammonia outlet pressure to 0.7MPa, and the PLC converts the data collected by the weight sensor LT1 into mass flow data. The mass flow rate is set to 6.0kg / h in the PLC, and is interlocked with the ammonia regulating valve LV1. The PLC automatically adjusts the valve opening of LV1 to stably control the mass flow rate at 6.0kg / h.
[0031] After the ammonia passes through the check valve, the ammonia distributor evenly distributes the ammonia in the stock liquid pipeline, and then goes to the static mixer with the stock liquid for full mixing.
[0032] Example 3
[0033] Please refer to Figure 1 This embodiment provides an ammonia system for polyacrylonitrile spinning stock solution. The viscosity of the polyacrylonitrile spinning stock solution from the upstream side is 80,000 cP, the pressure sensor PT2 is 0.3 MPa, and the insulation device of the ammonia cylinder is passed with 35°C hot water. The temperature TT1 below the side of the ammonia cylinder is set to 20°C in the PLC, and is interlocked with the hot water regulating valve TV1 through the PLC. The PLC automatically adjusts the valve opening of TV1 to stably control the temperature of the ammonia cylinder at 20°C to avoid frost on the bottom of the ammonia cylinder.
[0034] Before opening the ammonia cylinder, record the initial total weight M3 of the ammonia cylinder and its accessories, then open the ammonia cylinder and the pressure reducing valve behind it, adjust the ammonia outlet pressure to 0.4MPa, and the PLC converts the data collected by the weight sensor LT1 into mass flow data. The mass flow rate is set to 10.0kg / h in the PLC, and is interlocked with the ammonia regulating valve LV1. The PLC automatically adjusts the valve opening of LV1 to stably control the mass flow rate at 10.0kg / h.
[0035] After the ammonia passes through the check valve, the ammonia distributor evenly distributes the ammonia in the stock liquid pipeline, and then goes to the static mixer with the stock liquid for full mixing.
[0036] The foregoing description of the specific exemplary embodiments of the present invention is for the purpose of explanation and illustration, and these descriptions are not intended to limit the present invention to the precise form disclosed, and according to the above-mentioned embodiments, many changes and variations can be made. The selection of the parameters in the embodiments is intended to explain the practical application of the present invention, so that those skilled in the art can realize and utilize various different embodiment schemes of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.
Claims
1. A polyacrylonitrile spinning solution ammoniation system, characterized in that: include: The ammonia cylinder insulation device has an open insulation cotton on the outside, which is tightened and loosened with Velcro, and a plastic heating pipe is installed inside, and hot water is passed through the heating pipe for insulation; a hot water regulating valve is provided on the hot water pipe in the inlet of the device, and a temperature sensor is provided at the lower part of the ammonia cylinder. The temperature sensor transmits the temperature signal of the ammonia cylinder to the PLC module, and the PLC module controls the valve opening of the hot water regulating valve to achieve the purpose of maintaining the temperature stability of the lower part of the ammonia cylinder; Weight sensor and ammonia regulating valve. The weight sensor is placed just below the ammonia cylinder. There is an ammonia regulating valve on the ammonia pipeline. The weight sensor transmits the weight signal of the ammonia cylinder and its accessories to the PLC module at all times. The PLC converts the weight signal into a weight loss signal per unit time, i.e., a mass flow signal. Then, the valve flux of the ammonia regulating valve is controlled through the PLC module to achieve the purpose of controlling the speed of ammonia addition. Pressure sensor, check valve. The pressure sensor is mainly used to detect the pressure value on the ammonia pipeline and the spinning solution pipeline. The check valve prevents the spinning solution on the solution pipeline from flowing to the ammonia pipeline. The ammonia distributor is a short flange tube with a jacket. Holes of the same size are evenly distributed on the inner tube of the jacket. The center of the outer tube of the short tube is connected to the ammonia pipeline to increase the contact area between ammonia and spinning solution, so as to achieve the purpose of uniform contact between ammonia and the solution. The flange on the ammonia distributor is connected to the flange on the main pipeline with bolts, and the flange on the ammonia pipeline is connected to the check valve with bolts. The ammonia distributor can be disassembled and cleaned at any time. Static mixer: After ammonia and spinning solution are mixed, they are further mixed in the static mixer to achieve the purpose of uniform mixing of ammonia and spinning solution.
2. The ammoniation system of polyacrylonitrile spinning solution according to claim 1, characterized in that: The amination system is used in any process between after polymerization and before spinning; the viscosity of the spinning solution from the upstream side is ≤150,000 cP.
3. The ammoniation system of polyacrylonitrile spinning solution according to claim 1, characterized in that: The ammonia cylinder and its accompanying ammonia cylinder insulation device, temperature sensor, weight sensor, hot water regulating valve, and pressure reducing valve are all in a one-in-one-standby form. When the ammonia cylinder weight sensor detects that the weight is no longer changing, it immediately switches to the standby ammonia cylinder to provide ammonia to ensure the continuity of the system.
4. The ammoniation system of polyacrylonitrile spinning solution according to claim 1, characterized in that: The temperature below the side of the ammonia cylinder is ≤30°C, and the temperature of the hot water is ≤35°C.
5. The ammoniation system of polyacrylonitrile spinning solution according to claim 1, characterized in that: The pressure of the ammonia pipeline is greater than the pressure of the spinning solution main pipeline.
6. The ammoniation system of polyacrylonitrile spinning solution according to claim 1, characterized in that: The hot water of the ammonia cylinder insulation device enters from the bottom and exits from the top; the heating pipes at the bottom are dense while the heating pipes at the top are relatively sparse.
7. The ammoniation system of polyacrylonitrile spinning solution according to claim 1, characterized in that: The weight sensor has an accuracy of more than 0.01g and a measuring range of more than 500kg. The PLC continuously receives the weight signal and converts it into a mass flow signal, i.e., a weight loss signal per unit time, such as 2.5kg / h. The converted mass flow signal is interlocked with the ammonia regulating valve to adjust the flow of ammonia according to the production line's capacity.
8. The ammoniation system of polyacrylonitrile spinning solution according to claim 1, characterized in that: The ammonia distributor is connected to the main pipeline and the ammonia pipeline with flanges and can be disassembled and cleaned in time.
9. The ammoniation system of polyacrylonitrile spinning solution according to claim 1, characterized in that: The static mixer is a combination of SX type and SK type.