Oiling system for polyacrylonitrile-based precursor production

Abstract

The utility model relates to the field of carbon fiber precursor production, and discloses an oiling system for polyacrylonitrile-based precursor production, which comprises an oil supply component, and a first oiling tank and a second oiling tank which are connected with the oil supply component, the first oiling tank is further connected with a first online concentration meter and a first heat exchanger, and the second oiling tank is further connected with a second online concentration meter. The first oiling tank is connected with an oil supply assembly, the second oiling tank is connected with a second online concentration meter and a second heat exchanger, the oil inlet of the circulating assembly is connected with the oil supply assembly, the first oiling tank and the second oiling tank, and the oil outlet of the circulating assembly is connected with the first oiling tank and / or the second oiling tank. The quality of the protofilament is improved, and the production cost is reduced by the recycled oil agent.

Description

TECHNICAL FIELD

[0001] The utility model relates to the carbon fiber precursor production field, concretely relates to a kind of oiling system for polyacrylonitrile-based precursor production. BACKGROUND

[0002] Carbon fiber is a kind of high-strength, high-modulus high-performance fiber, with low density, high conductivity, corrosion resistance, high temperature resistance, friction resistance and other characteristics, widely used in sports and leisure, transportation, aerospace, wind power blades, building materials and other fields. Because of its own multiple excellent performance, and can be combined with multiple material production, in recent years, carbon fiber new material industry continues to develop.

[0003] Most of the carbon fibers on the market are polyacrylonitrile carbon fibers using polyacrylonitrile as raw material. Carbon fiber is a brittle material, surface defects are an important reason to limit its tensile strength, and some of the surface defects are produced in the spinning process. In the production process of polyacrylonitrile precursor, the main function of spinning oil is to play a lubricating role, reduce the friction between the surface of the yarn and the roller and other equipment, at the same time, reduce the static electricity produced by friction, reduce the surface defects of the fiber, and increase the bunching of the yarn. At the same time, in the carbonization process, the yarn is easy to occur hot melting and other phenomena, and the precursor oil can avoid the adhesion or parallel yarn between the filaments, and can also play a protective role for the yarn during oxidation and carbonization. Good quality oil and reasonable oiling method can help improve the quality of the precursor and improve the performance of the carbon fiber. Two-stage oiling can reduce the occurrence of small pores in the densification process of the precursor, and generally adds an oil agent after heat stretching and before drying and densification, and adds a second oil agent after drying and densification.

[0004] Oil tank concentration is an important factor affecting the oil content of the precursor, and too low oil tank concentration can lead to poor yarn bunching and produce hair and broken yarns; too high oil tank concentration can cause a large amount of oil to adhere to the surface of the precursor, which may cause insufficient densification. Oil tank temperature also has a great influence on the oiling quality, and too low oil tank temperature can not achieve ideal oiling effect of the precursor; too high oil tank temperature can cause oil demulsification and deterioration, affecting the oiling quality of the precursor and further affecting the performance of the carbon fiber product.

[0005] At present, in the production process, the tow is washed and drawn after the process, and then enters the oil tank. The oil agent is added in the oil tank to ensure the concentration of the oil agent in the oil tank. Different oil agent supplement in the oiling system may cause the fluctuation of the concentration of the oil tank, and then affect the oil content of the raw silk product. At present, the concentration of the oil tank is mainly detected by manual sampling, which takes a long time and is difficult to monitor the concentration of the oil tank at any time. At the same time, due to the high temperature of the previous process, part of the heat enters the oiling tank with the tow, which causes the temperature of the oil tank to be too high. The oil agent stays in the high-temperature oil tank for a long time, which may cause demulsification and deterioration, and then affect the quality of the carbon fiber product and its application in the composite material. The oiling tank uses overflow method to control the liquid level and adjust the balance. The overflow oil agent is directly discharged and treated, which may cause environmental pollution and waste a lot of oil agent, and increase the production and operation cost of the carbon fiber raw silk.

[0006] CN210684015U discloses a spinning oil temperature control system, which comprises an oil storage tank, a heat exchanger and a warm water tank. The heat exchanger is connected with the oil storage tank through a first oil pipeline, and is connected with an oil agent pump through a second oil pipeline. The second oil pipeline is provided with a jacket pipe, which comprises an inner oil pipe and a warm water jacket pipe outside the oil pipe. The warm water output pipe of the warm water tank is connected with the water inlet of the warm water jacket pipe. The water outlet of the warm water jacket pipe is connected with the water inlet of the heat exchanger through an intermediate warm water pipeline. The water outlet of the heat exchanger is connected with the warm water tank through a warm water return pipe. The system uses the warm water tank to solve the problem of oil agent temperature control, but cannot realize accurate online control of the oil agent concentration, and cannot solve the problem of overflow oil agent discharge, which may cause environmental pollution.

[0007] CN206590686U discloses an oil agent recycling device applied to a winding machine, which comprises a controller, a recycling tank, an oil agent tank connected with the recycling tank through an oil return pipeline, and a first driving motor for driving the oil agent flow in the oil return pipeline. The recycling tank is arranged below the second upper water roller along the length direction of the winding machine. The oil agent tank is connected with the oil supply pipeline above the oil supply gap. A plurality of liquid level sensors are arranged in the recycling tank along the height direction thereof. The liquid level sensors, the controller and the first driving motor are electrically connected in sequence. The oil agent recycling device realizes the recycling of expensive oil agent through the design of the recycling tank, the oil agent tank and the corresponding driving motor, and reduces the power consumption caused by idling. However, the patent directly recycles the oil agent of the winding machine, and directly recycles the overflow oil agent to the oil agent tank through the recycling tank, which cannot accurately control the concentration and temperature of the recycled oil agent, cannot ensure that the fresh recycled oil agent returns to the oil agent circulation system immediately, and thus cannot ensure the quality of the recycled oil agent and the oiling effect when the recycled oil agent reenters the oiling system. Practical new type

[0008] The utility model discloses a purpose is to overcome the prior art's problem of not being able to effectively control oil groove concentration and temperature, provide a kind of polyacrylonitrile base filament production's oiling system, the temperature and concentration of the system can effectively control oil groove, it is favorable to improve the quality of filament, and oil agent can also be recycled, save cost.

[0009] In order to realize the above-mentioned purpose, the utility model provides an oiling system, wherein the oiling system comprises:

[0010] Oil supply assembly;

[0011] One oiling groove is connected with the oil supply assembly, and the one oiling groove is further connected with a first online concentration instrument and a first heat exchanger;

[0012] Two oiling grooves are connected with the oil supply assembly, and the two oiling grooves are further connected with a second online concentration instrument and a second heat exchanger;

[0013] A circulating assembly is connected with the oil supply assembly, the one oiling groove and the two oiling grooves at an oil inlet, and is connected with the one oiling groove and / or the two oiling grooves at an oil outlet.

[0014] The first and second online concentration instruments can be used to obtain the real-time concentration of the oil agent in the one oiling groove and the two oiling grooves, respectively, and the concentration of the oil agent in the oil grooves can be effectively controlled by adjusting the amount of oil provided by the oil supply assembly. The temperature of the oil agent in the one oiling groove and the two oiling grooves can be effectively controlled by the first heat exchanger and the second heat exchanger, thereby achieving effective control of the concentration and temperature of the oil agent in each oil groove, which is conducive to improving the quality of the original silk. At the same time, when the concentration of the oil agent in the one oiling groove and the two oiling grooves is adjusted, the excess oil agent enters the circulating assembly, and the circulating assembly simultaneously receives the oil agent from the oil supply assembly, so that the concentration of the oil agent in the circulating assembly can be adjusted, and the part of the oil agent is further returned to the one oiling groove and / or the two oiling grooves through the circulating assembly, which is conducive to saving cost.

[0015] Preferably, the one oiling groove is provided with a first overflow area, and the excess oil agent in the one oiling groove can overflow into the first overflow area, and the first overflow area is connected with the oil inlet of the circulating assembly through a first circulating pipe.

[0016] The two oiling grooves are provided with a second overflow area, and the excess oil agent in the two oiling grooves can overflow into the second overflow area, and the second overflow area is connected with the oil inlet of the circulating assembly through a second circulating pipe.

[0017] With the above structure, when the oil in the first and second upper oil grooves is relatively more, the excess oil will enter the corresponding first and second overflow areas through overflow mode and be recycled through the circulating assembly, thereby recycling fresh overflow oil in real time, reducing oil loss, saving energy and protecting the environment, and ensuring oil quality.

[0018] Preferably, the oil supply assembly comprises:

[0019] A first oil supply groove connected to the first upper oil groove through a first feeding pipeline;

[0020] A second oil supply groove connected to the second upper oil groove through a second feeding pipeline.

[0021] With this structure, the first and second upper oil grooves are supplied with oil through the first and second oil supply grooves, respectively, and the concentration of the oil in the oil grooves can be controlled by controlling the amount of oil supplied in combination with the real-time concentration obtained from the online concentration instrument.

[0022] Preferably, the circulating assembly comprises a circulating tank, the first oil supply groove is connected to an oil inlet of the circulating tank through a third feeding pipeline, an oil outlet of the circulating tank is connected to the second upper oil groove through a circulating pipe, and the second heat exchanger is arranged on the circulating pipe. With this structure, the excess oil in the first and second upper oil grooves enters the circulating tank and can be further replenished through the first oil supply groove, which facilitates the control of the concentration of the oil in the circulating tank and ensures that the oil meeting the requirements is fed into the second upper oil groove.

[0023] Preferably, the oil outlet of the first upper oil groove is connected to the first online concentration instrument and the first heat exchanger in sequence through a first regulating pipeline, and a first spray pipe is connected to the outlet end of the first regulating pipeline, which is located above the first upper oil groove and used for spraying oil on the raw wire in the first upper oil groove. With this structure, the temperature of the oil in the first upper oil groove can be accurately controlled through the first heat exchanger, the oil meeting the requirements is sprayed on the raw wire through the first spray pipe, and the first online concentration instrument arranged on the circuit can realize real-time online detection of the concentration of the oil in the first upper oil groove, so that the concentration of the oil in the oil groove meets the requirements by adjusting the amount of oil from the oil supply assembly based on the real-time concentration obtained.

[0024] Preferably, the first oil outlet of the second upper oil groove is connected to the second online concentration instrument through a second regulating pipeline, and the outlet end of the second regulating pipeline is connected to the oil return port of the second upper oil groove. With this structure, the concentration of the oil in the second upper oil groove can be obtained in real time through the second online concentration instrument, and the concentration of the oil in the oil groove can meet the requirements by adjusting the amount of oil from the oil supply assembly based on the real-time concentration obtained.

[0025] Preferably, the second oil outlet of the second oiling groove is connected with the oil inlet of the circulating groove through a third circulating pipe. With this structure, if necessary, part of the oil in the second oiling groove is sent to the circulating groove, and the concentration is adjusted again before being recycled.

[0026] Preferably, a first flow meter is arranged on the third feeding pipe.

[0027] The circulating groove is further connected with a third pure water pipe, and a second flow meter is arranged on the third pure water pipe.

[0028] The circulating groove is further connected with a third online concentration meter, and the third online concentration meter is in signal connection with the first flow meter and the second flow meter.

[0029] With the above structure, the amount of oil and water entering the circulating groove can be detected in real time and online through the first flow meter and the second flow meter, and the concentration of the oil in the circulating groove can be detected in real time and online through the third online concentration meter, so that the concentration of the oil in the circulating groove can be adjusted conveniently.

[0030] Preferably, a second spraying pipe is arranged above the second oiling groove, and the outlet end of the circulating pipe is connected with the second spraying pipe, which is arranged above the second oiling groove and used for spraying oil on the raw filaments in the second oiling groove. A filter is arranged on the circulating pipe. With this structure, the raw filaments in the second oiling groove can be sprayed through the second spraying pipe. Since part of the oil in the circulating groove is the oil used in the first oiling groove and the second oiling groove, the oil can be filtered through the filter to improve the quality of the oil. The type of the filter is not particularly limited, and can be, for example, a basket filter.

[0031] Preferably, the oil supply assembly further comprises:

[0032] A first oil agent preparation groove is connected with a first oil agent mother liquor pipe and a first pure water pipe, and the oil outlet of the first oil agent preparation groove is connected with the oil inlet of the first oil agent feeding groove.

[0033] A second oil agent preparation groove is connected with a second oil agent mother liquor pipe and a second pure water pipe, and the oil outlet of the second oil agent preparation groove is connected with the oil inlet of the second oil agent feeding groove.

[0034] With the above structure, the concentration of the oil in the first oil agent preparation groove and the second oil agent preparation groove can be adjusted by adjusting the ratio between the oil agent mother liquor and water, and the oil meeting the requirements can be sent to the first oil agent feeding groove, the second oil agent feeding groove and / or the circulating groove to supply oil to the corresponding oil groove.

[0035] Preferably, a first agitator is arranged in the first oil agent preparation groove, and a second agitator is arranged in the second oil agent preparation groove.

[0036] Preferably, a third stirrer is arranged in the circulating tank.

[0037] With the above structure, the oil material can be stirred uniformly.

[0038] Preferably, the first oiling tank and the second oiling tank are connected through a drying machine. With this structure, after the oiling through the first oiling tank, the raw silk can be dried and densified through the drying machine, and then enter the second oiling tank for oiling again.

[0039] The oiling system in the production of polyacrylonitrile-based raw silk provided by the utility model not only realizes online accurate regulation and control of the oil agent concentration in the first oiling tank, the second oiling tank and the circulating tank, reduces the workload of frequent manual adjustment of the oil agent supplementing amount and frequent sampling detection, and can adjust the oil agent temperature according to the process requirement by adjusting and controlling the heat exchange medium flow of the first heat exchanger and the second heat exchanger, controls the oil agent temperature in the first oiling tank, the second oiling tank and the circulating tank at the target value; at the same time, the overflow oil agent can be recycled in real time through the circulating tank, reduces the oil agent loss, saves energy and protects the environment, and guarantees the oil agent quality.

[0040] The utility model is used in the polyacrylonitrile-based raw silk oiling process, can accurately control the oil agent concentration and temperature, saves energy and reduces consumption, effectively improves the oiling effect, lays a good foundation for the subsequent production and processing of carbon fibers. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is the structural schematic diagram of example 1;

[0042] Figure 2 is the structural schematic diagram of comparative example 1

[0043] Figure 3 is the structural schematic diagram of comparative example 2.

[0044] BRIEF DESCRIPTION OF DRAWINGS

[0045] 1-first oil agent mother liquor pipe; 2-first pure water pipe; 3-first oil agent blending tank; 4-first stirrer; 5-first oil agent supply tank; 6-first feeding pipeline; 7-first oiling tank; 8-first online concentration instrument; 9-first pump; 10-first heat exchanger; 11-first spraying pipe; 12-first overflow area; 13-dryer; 14-second oil agent mother liquor pipe; 15-second pure water pipe; 16-second oil agent blending tank; 17-second stirrer; 18-second oil agent supply tank; 19-second feeding pipeline; 20-second oiling tank; 21-second online concentration instrument; 22-second pump; 23-second overflow area; 24-circulation tank; 25-third stirrer; 26-third online concentration instrument; 27-second flow meter; 28-first flow meter; 29-third pure water pipe; 30-second heat exchanger; 31-third pump; 32-filter; 33-second spraying pipe; 34-third feeding pipeline; 35-first control pipeline; 36-second control pipeline; 37-circulation pipe; 38-third circulation pipe; 39-first circulation pipe; 40-second circulation pipe. DETAILED DESCRIPTION

[0046] The terms "first", "second", "third", "etc." are only used for descriptive purpose and can not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated thereby, thus the features with "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified and limited.

[0047] In the description of the present application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0048] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0049] Embodiment 1

[0050] An oiling system, wherein the oiling system comprises:

[0051] An oil supply assembly;

[0052] A first oiling groove 7 connected to the oil supply assembly, the first oiling groove 7 is further connected with a first online concentration instrument 8 and a first heat exchanger 10;

[0053] A second oiling groove 20 connected to the oil supply assembly, the second oiling groove 20 is further connected with a second online concentration instrument 21 and a second heat exchanger 30;

[0054] A circulating assembly, the oil inlet of which is connected to the oil supply assembly, the first oiling groove 7 and the second oiling groove 20, and the oil outlet of which is connected to the first oiling groove 7 and / or the second oiling groove 20.

[0055] In some embodiments, the oil agent in the circulating assembly can be delivered to the first oiling groove 7 through the pipeline, in other embodiments, the oil agent in the circulating assembly can be delivered to the second oiling groove 20 through the pipeline, and in other embodiments, the oil agent in the circulating assembly can be delivered to the first oiling groove 7 and the second oiling groove 20 through the pipeline at the same time. In the present example, the oil agent in the circulating assembly is delivered to the second oiling groove 20 through the pipeline.

[0056] Specifically, the oil supply assembly comprises:

[0057] A first oil agent preparation tank 3 and a first oil agent supply tank 5, wherein the first oil agent preparation tank 3 is connected with a first oil agent mother liquor pipe 1 and a first pure water pipe 2, a first agitator 4 is arranged in the first oil agent preparation tank 3, the oil outlet of the first oil agent preparation tank 3 is connected with the oil inlet of the first oil agent supply tank 5, and the oil outlet of the first oil agent supply tank 5 is connected with the oil inlet of the first oiling groove 7 through a first feeding pipeline 6;

[0058] A second oiling agent preparation tank 16 and a second oiling agent supply tank 18, wherein the second oiling agent preparation tank 16 is connected with a second oil agent mother liquor pipe 14 and a second pure water pipe 15, a second agitator 17 is arranged in the second oiling agent preparation tank 16, an oil outlet of the second oiling agent preparation tank 16 is connected with an oil inlet of the second oiling agent supply tank 18, and an oil outlet of the second oiling agent supply tank 18 is connected with an oil inlet of the second oiling groove 20 through a second feeding pipe 19.

[0059] It can be seen from Figure 1 that the outlet ends of the first feeding pipe 6 and the second feeding pipe 19 are respectively connected with spray heads, and the corresponding first oiling groove 7 and the second oiling groove 20 are supplied with oil through the spray heads, and the grooves of the first oiling groove 7 and the second oiling groove 20 form the corresponding oil inlets, and the corresponding spray heads spray oil from the first oiling agent supply tank 5 or the second oiling agent supply tank 18 to achieve the purpose of oil supply.

[0060] An oil outlet of the first oiling groove 7 is connected with the first online concentration instrument 8 and the first heat exchanger 10 in sequence through a first control pipe 35, a first pump 9 is further arranged on the first control pipe 35, and a first spray pipe 11 is connected with the outlet end of the first control pipe 35, the first spray pipe 11 is located above the first oiling groove 7, and is used for spraying oil on the raw yarn in the first oiling groove 7.

[0061] A first oil outlet of the second oiling groove 20 is connected with the second online concentration instrument 21 through a second control pipe 36, a second pump 22 is further arranged on the second control pipe 36, and the outlet end of the second control pipe 36 is connected with an oil return port of the second oiling groove 20.

[0062] A first overflow area 12 is arranged in the first oiling groove 7, and the excess oil agent in the first oiling groove 7 can overflow into the first overflow area 12, a circulating oil outlet of the first overflow area 12 is connected with an oil inlet of the circulating assembly through a first circulating pipe 39, a second overflow area 23 is arranged in the second oiling groove 20, and the excess oil agent in the second oiling groove 20 can overflow into the second overflow area 23, a circulating oil outlet of the second overflow area 23 is connected with the oil inlet of the circulating assembly through a second circulating pipe 40, and in the example, each overflow area is formed as follows: an overflow baffle is arranged in the first oiling groove 7 and the second oiling groove 20, the height of the overflow baffle is less than the depth of the corresponding first oiling groove 7 and second oiling groove 20, and the overflow baffle and the corresponding groove wall of the first oiling groove 7 and the second oiling groove 20 respectively form the first overflow area 12 and the second overflow area 23.

[0063] The circulating assembly comprises a circulating tank 24, the first oil supply tank 5 is connected with the oil inlet of the circulating tank 24 through a third feeding pipeline 34, the first overflow area 12 and the second overflow area 23 are respectively connected with the oil inlet of the circulating tank 24, the oil outlet of the circulating tank 24 is connected with the second oil supply tank 20 through a circulating pipeline 37, specifically, the outlet end of the circulating pipeline 37 is connected with a second spraying pipeline 33, the second spraying pipeline 33 is located above the second oil supply tank 20 and is used for spraying oil to the raw yarn in the second oil supply tank 20, and a filter 32 and a third pump 31 are arranged on the circulating pipeline 37. The second heat exchanger 30 is arranged on the circulating pipeline 37, and the second oil outlet of the second oil supply tank 20 is connected with the oil inlet of the circulating tank 24 through a third circulating pipeline 38.

[0064] As shown in the figure, the third agitator 25 is arranged in the circulating tank 24, the third pure water pipeline 29 is connected with the circulating tank 24, the second flow meter 27 is arranged on the third pure water pipeline 29, and the third online concentration instrument 26 is connected with the circulating tank 24 and is in signal connection with the first flow meter 28 and the second flow meter 27.

[0065] In the embodiment, the first pump 9, the second pump 22 and the third pump 31 are all volume pumps. The temperature of the oil in the first oil supply tank 7 and the second oil supply tank 20 can be regulated by regulating the temperature of the heat exchange medium in the first heat exchanger 10 and the second heat exchanger 30, so that the temperature can be adjusted at will according to the needs and meets the processing needs.

[0066] The concentration of the oil in the first oil supply tank 7 is mainly adjusted by adjusting the amount of oil from the first oil supply tank 5, and the real-time online detection of the concentration of the oil is realized through the first online concentration instrument 8.

[0067] The concentration of the oil in the second oil supply tank 20 is mainly controlled by adjusting the amount of oil from the second oil supply tank 18 and the concentration of the oil circulatingly supplemented through the circulating tank 24, the real-time online detection of the concentration of the oil is realized through the second online concentration instrument 21, and the real-time detection and control of the concentration of the supplemented oil in the circulating tank 24 are realized through the third online concentration instrument 26.

[0068] The oil tank concentration can be monitored in real time, the concentration of the first oil supply tank and the second oil supply tank can be accurately controlled, and the quality of the raw yarn oiling is improved.

[0069] Comparative example 1

[0070] The structure is as Figure 2The difference between the embodiment 1 and the embodiment 2 is that: the first on-line concentration instrument 8 and the first heat exchanger 10 are not connected to the first oiling tank 7, the second on-line concentration instrument 21, the second pump 22 and the second heat exchanger 30 are not connected to the second oiling tank 20, and the second oil outlet of the second oiling tank 20 is connected to the third pump 31 and the second spraying pipe 33.

[0071] The fiber bundle enters the oil tank after the water washing and drawing processes, and the oil agent is added in the first oiling tank 7 through the first feeding pipe 6 to ensure the concentration of the oil agent in the oil tank. After the drying and densification treatment by the drying machine 13, the fiber bundle enters the second oiling tank 20, and the oil agent is added through the second feeding pipe to ensure the concentration of the oil agent in the oil tank.

[0072] The oiling of the first oiling tank 7 and the second oiling tank 20 is controlled by the overflow of the oil agent to balance the liquid level, and the fresh oil agent in the two tanks is discharged through the first overflow area 12 and the second overflow area 23, respectively.

[0073] The flow rate of the fresh overflow oil agent in the first overflow area 12 and the second overflow area 23 is about 400 mL / min, and the concentration is about 2.4 wt% (based on the total amount of the overflow oil agent), which can easily cause environmental pollution and a large amount of oil agent waste, increasing the production and operation cost of the carbon fiber precursor.

[0074] The concentration of the oil agent in the first oiling tank 7 and the second oiling tank 20 is detected by manual sampling and sending, which takes about 3 hours, and it is difficult to monitor and control the concentration of the oil agent in the oil tank at any time.

[0075] Since the previous process of the first oiling tank 7 is hot drawing, the process temperature is much higher than the temperature of the oil agent in the first oiling tank 7. The fiber bundle is immersed in the hot drawing tank, and part of the water and heat enters the first oiling tank 7 with the fiber bundle, resulting in a higher temperature in the first oiling tank 7 in actual production. The measured temperature of the first oiling tank 7 of the precursor is more than 40℃.

[0076] The previous process of the second oiling tank 20 is drying and densification, and the temperature is also relatively high. However, since the moisture content in the fiber bundle is relatively low, the heat is lost at the outlet of the drying machine 13 before entering the second oiling tank 20, and the heat carried into the second oiling tank 20 is relatively small, which has little effect on the temperature of the second oiling tank 20. The measured temperature of the second oiling tank 20 is about 35℃.

[0077] The production of the embodiment 1 and the comparative example 1 is analyzed as follows:

[0078] The first oil tank 7 and the second oil tank 20 are cleaned, and for the example 1, the first heat exchanger 10 and the second heat exchanger 30 are respectively supplied with cooling water to control the oil temperature in the first oil tank 7 and the second oil tank 20, and the operation is carried out for two cycles. The example 1 is also operated for two cycles, and the oil deterioration, demulsification and precipitation in the first oil tank 7 of the example 1 and the comparative example 1 are observed. It is found that after two cycles of operation, the white or light yellow paste in the first oil tank 7 of the example 1 is obviously reduced compared with the comparative example 1.

[0079] In the case that the spinning process conditions are consistent except for the oil tank temperature of the first oil tank 7 and the second oil tank 20, the raw filaments produced by the comparative example 1 and the example 1 (the temperature of the first oil tank 7 and the second oil tank 20 is 25℃) are subjected to mechanical property test. Each 10 samples are taken as a group to take average value, and 3 groups of samples of the comparative example 1 are recorded as serial numbers 1, 2 and 3, and 3 groups of samples of the example 1 are recorded as serial numbers 4, 5 and 6.

[0080] The raw filaments of the comparative example 1 and the example 1 have no obvious abnormality in the raw filament winding process, and the samples are all white and soft in appearance. The 1-2 and 4-6 samples have no obvious adhesion, and the 3 sample has slight parallelism. As shown in Table 1, the strength of the 1-3 samples from the comparative example 1 is slightly lower than that of the 4-6 samples from the example 1, the modulus of the 1-3 samples is slightly lower than that of the 4-6 samples, the elongation of the raw filaments has large difference between the samples, but there is no obvious comparison trend before and after the optimization of the oil tank temperature, and the oil content of the raw filaments has no obvious difference.

[0081] Table 1 Comparison of raw filament performance before and after optimization of oil tank temperature

[0082]

[0083] In the case that the remaining process conditions are consistent, two groups of raw filaments prepared by the comparative example 1 and the example 1 are selected to produce carbon fibers, which are recorded as the first group and the second group, and the mechanical properties and production conditions are recorded and tested. The results are shown in Table 2, which shows that the carbon fibers produced by the two groups of samples have little difference in mechanical properties, but have obvious difference in production conditions. The sample raw filaments from the comparative example 1 are wound around the roller many times in the oxidation and carbonization process, and the number of hair and broken filaments of the carbon fiber product is increased compared with the sample from the example 1.

[0084] Table 2 Oxidation and carbonization production conditions before and after optimization of oil tank temperature

[0085]

[0086] The production operation between the two groups of samples showed that the demulsification and deterioration of the oil agent has a certain impact on the oiling quality of the raw yarn. This utility model can accurately control the temperature of the oil bath, which helps to improve the oiling quality of the raw yarn and has a positive impact on the subsequent oxidation and carbonization production quality.

[0087] Comparative Example 2

[0088] like Figure 3 As shown, the only difference between it and Embodiment 1 is that there is no circulation tank 24 and its related connecting pipes, the second oil outlet of the second oil tank 20 is connected to the second heat exchanger 30, and the oil outlet of the second heat exchanger 30 is connected to the second spray pipe 33.

[0089] Cooling water is introduced into the first heat exchanger 10 and the second heat exchanger 30 respectively to cool down the oil in the first oil tank 7 and the second oil tank 20. The oil temperature can be adjusted according to the process requirements by regulating the flow rate of the heat exchange medium. After cooling, the oil temperature in the first oil tank 7 and the second oil tank 20 is controlled at 20-30℃.

[0090] Production tests were conducted based on the structures of Example 1 and Comparative Example 2, as detailed below:

[0091] In Example 1, the first oil tank 7 and the second oil tank 20 control the liquid level balance through oil overflow. The concentration of fresh overflow oil in the first oil tank 7 is about 2.4 wt% (based on the total amount of overflow oil), which is close to the concentration of oil in the second oil tank 20. The fresh overflow oil in the first oil tank 7 and the second oil tank 20 enters the circulation tank 24 through the first overflow area 12 and the second overflow area 23, respectively. The concentration of oil in the circulation tank 24 is detected by the third online concentration meter 26. The concentration of oil in the circulation tank 24 is controlled by the second flow meter 27 controlling the amount of water added and the first flow meter 28 controlling the amount of oil added from the first oil supply tank 5. The oil in the circulation tank 24 is sent to the second oil tank 20 for recycling after the temperature is regulated by the second heat exchanger 30. Specifically, the temperature of oil in the first oil tank 7 and the second oil tank 20 is controlled at 25°C.

[0092] The control results in Comparative Example 2 were consistent with those in Example 1, with the oil agent temperatures in the first oil tank 7 and the second oil tank 20 being 25°C.

[0093] The precursor fibers produced in Comparative Example 2 and Example 1 were analyzed. The results are shown in Table 3. The experimental results show that there is no significant difference in the mechanical properties of the precursor fibers from the two sources.

[0094] Table 3 Mechanical Properties Analysis of Raw Fiber

[0095]

[0096] The results of the analysis of the unit consumption of the oil agent of the raw yarn and the unit cost of Example 1 and Comparative Example 2 are shown in Table 4. The test results show that, compared with Comparative Example 2, Example 1 with oil agent recycling has a significant reduction in the unit consumption of the oil agent of the raw yarn and a great reduction in the unit cost, which is beneficial to cost reduction and efficiency increase in factory production.

[0097] Table 4 Unit cost of oil agent

[0098]

[0099] It can be seen that the unit consumption and unit cost of Example 1 with oil agent recycling are significantly reduced compared with Comparative Example 2 without oil agent recycling.

[0100] The preferred embodiments of the utility model are described in detail above in combination with the drawings, but the utility model is not limited thereto. Within the technical concept of the utility model, the technical solution of the utility model can be subjected to various simple modifications, for example, the lifting structure can be changed into other mechanical lifting structures, and various specific technical features can be combined in any suitable manner. In order to avoid unnecessary repetition, the utility model will not describe various possible combination manners again. However, these simple modifications and combinations should also be regarded as the disclosed content of the utility model and belong to the protection scope of the utility model.

Claims

1. An oiling system for the production of polyacrylonitrile-based precursors, characterized in that it comprises: The oiling system comprises: an oil supply assembly; a first oiling groove connected with the oil supply assembly, the first oiling groove being further connected with a first on-line concentration instrument and a first heat exchanger; a second oiling groove connected with the oil supply assembly, the second oiling groove being further connected with a second on-line concentration instrument and a second heat exchanger; a circulating assembly, an oil inlet of which being connected with the oil supply assembly, the first oiling groove and the second oiling groove, and an oil outlet of which being connected with the first oiling groove and / or the second oiling groove.

2. The oiling system of claim 1, wherein The first oiling groove is provided with a first overflow area, and the excess oil in the first oiling groove can overflow into the first overflow area, the first overflow area being connected with the oil inlet of the circulating assembly through a first circulating pipe. The second oiling groove is provided with a second overflow area, and the excess oil in the second oiling groove can overflow into the second overflow area, the second overflow area being connected with the oil inlet of the circulating assembly through a second circulating pipe.

3. The oiling system of claim 2, wherein The oil supply assembly comprises: a first oil supply groove connected with the first oiling groove through a first feeding pipe; a second oil supply groove connected with the second oiling groove through a second feeding pipe.

4. The oiling system of claim 3, wherein The circulating assembly comprises a circulating groove, the first oil supply groove being connected with an oil inlet of the circulating groove through a third feeding pipe, an oil outlet of the circulating groove being connected with the second oiling groove through a circulating pipe, the circulating pipe being provided with the second heat exchanger.

5. The oiling system according to any one of claims 1-4, characterized in that, The oil outlet of the first oiling groove is connected with the first on-line concentration instrument and the first heat exchanger in sequence through a first control pipe, an outlet end of the first control pipe being connected with a first spraying pipe located above the first oiling groove and used for spraying oil on the raw filaments in the first oiling groove. The first oil outlet of the second oiling groove is connected with the second on-line concentration instrument through a second control pipe, an outlet end of the second control pipe being connected with an oil return port of the second oiling groove.

6. The oiling system of claim 4, wherein The second oil outlet of the second oiling groove is connected with the oil inlet of the circulating groove through a third circulating pipe.

7. The oiling system according to claim 4 or 6, characterized in that The third feeding pipe is provided with a first flow meter. The circulating groove is further connected with a third pure water pipe provided with a second flow meter. The circulating groove is further connected with a third on-line concentration instrument connected with the first flow meter and the second flow meter.

8. The oiling system of claim 7, wherein, An outlet end of the circulating pipe is connected with a second spraying pipe located above the second oiling groove and used for spraying oil on the raw filaments in the second oiling groove, the circulating pipe being provided with a filter.

9. The oiling system of claim 4, wherein, The oil supply assembly further comprises: a first oil preparation groove connected with a first oil mother liquor pipe and a first pure water pipe, an oil outlet of the first oil preparation groove being connected with an oil inlet of the first oil supply groove; a second oil preparation groove connected with a second oil mother liquor pipe and a second pure water pipe, an oil outlet of the second oil preparation groove being connected with an oil inlet of the second oil supply groove.

10. The oiling system of claim 9, wherein, The first oil preparation groove is provided with a first stirrer, and the second oil preparation groove is provided with a second stirrer. The circulating groove is provided with a third stirrer.

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