Preparation method, production system and application of conductive filler for high-voltage cable shielding material

Abstract

The present invention relates to the field of preparation of conductive materials for cable shielding materials, and discloses a preparation method, production system and application of conductive fillers for high-voltage cable shielding materials. The preparation method comprises: S1, mixing a first solution containing raw oil with a carbon black raw material in a spraying form to obtain a mixed material; wherein the oil absorption value of the carbon black raw material is 180-220 (10 ‑5 m 3 / kg); wherein the feedstock oil has an aromatic content of 70-85wt% and an asphaltene content of less than 0.1wt%; S2. In the presence of a carrier gas, the mixture is flowed in a heating section to perform indirect heat exchange with a high-temperature fluid; the temperature of the high-temperature fluid is not less than 1800°C, and the heat exchange time is 30-120 seconds. The conductive filler produced by this preparation method has both a high degree of structure and graphitization, and can meet the performance requirements of cable shielding materials.

Description

Technical Field

[0001] The present invention relates to the field of preparation of conductive materials for cable shielding materials, and in particular to a preparation method, a production system and applications of conductive fillers for high-voltage cable shielding materials. Background Art

[0002] Carbon black is a black powdery substance produced by the incomplete combustion or pyrolysis of hydrocarbons in the gas phase under strictly controlled temperature and oxygen content conditions. Carbon black is primarily composed of various forms of carbon, with trace amounts of other elements such as oxygen, hydrogen, and sulfur. The most basic unit of carbon black is a nearly spherical primary particle, typically ranging in size from 10 to 100 nm. These primary particles often fuse or coalesce into three-dimensional, dendritic or fibrous aggregates, which can grow to sizes ranging from 10 to 500 μm, depending on the type of carbon black.

[0003] The structure of carbon black is determined by aggregate size, shape, the number of particles per aggregate, and the average mass. Carbon blacks with different structures exhibit significant differences in performance. In addition to carbon black's structure, the degree of graphitization also significantly influences its electrical properties. Carbon black production typically controls its structure based on performance requirements. Testing and characterization of various indicators of finished carbon black products can numerically describe the strengths and weaknesses of certain properties.

[0004] Semi-conductive shielding material is a functional material used in cables, especially high-voltage cables, to eliminate the air gap between the insulation layer and the outer metal shielding layer, thereby protecting the main insulation layer from damage. Cable shielding materials typically use conductive carbon black as a conductive filler to achieve their semi-conductivity. For high-voltage cable shielding materials, especially high-voltage submarine cable shielding materials, conductive fillers with even better performance are required. Superconductive carbon black, due to its high structure and high degree of graphitization, is a material that is very suitable for use as a high-performance conductive filler. Superconductive carbon black is particularly important for semi-conductive shielding materials of high-voltage submarine cables. Currently, the most common superconductive carbon black product is acetylene black, and some carbon blacks produced by special processes can also be used as superconductive carbon black. However, existing superconductive carbon blacks, including acetylene carbon black, are all non-furnace carbon blacks, which are difficult to produce and have high production costs. In addition, the corresponding superconductive carbon black production technology is still lacking in China.

[0005] Furnace black is produced through incomplete combustion or pyrolysis of natural gas or high-aromatic oil in a dedicated reactor. However, conventional furnace black reactors are limited in their structure and graphitization, which are unable to meet the performance requirements of conductive fillers for cable shielding materials. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problem that conventional carbon black in the prior art has low structural degree and graphitization degree, and cannot meet the performance requirements of conductive fillers for cable shielding materials. A preparation method, production system and application of conductive fillers for high-voltage cable shielding materials are provided. The conductive filler prepared by this preparation method has both high structural degree and graphitization degree, and can meet the performance requirements of cable shielding materials.

[0007] In order to achieve the above object, the present invention provides a method for preparing a conductive filler for a cable shielding material, the preparation method comprising:

[0008] S1, mixing the first solution containing the raw oil with the carbon black raw material in the form of a spray, and then cooling to obtain a mixed material; wherein the oil absorption value of the carbon black raw material is 160-220 (10 -5 m 3 / kg);

[0009] The aromatic content in the raw oil is 70-85wt%, and the asphaltene content is less than 0.1wt%;

[0010] S2. In the presence of a carrier gas, the mixed material flows in a heating section to perform indirect heat exchange with a high-temperature fluid;

[0011] The temperature of the high-temperature fluid is not lower than 1800° C., and the heat exchange time is 30-120 seconds.

[0012] A second aspect of the present invention provides a production system for a conductive filler for cable shielding materials, the production system comprising a carbon black raw material supply unit, a raw oil supply unit, a mixing unit, and a high-temperature treatment device;

[0013] The mixing unit includes a mixing device, a carbon black separation device and a residual gas separation device which are connected in sequence; the upper portion of the mixing device is provided with a spray inlet connected to the raw oil supply unit, and a carbon black inlet connected to the carbon black raw material supply unit;

[0014] The high-temperature treatment device includes a material pipeline and an insulation layer that are sheathed from the inside out. An annular gap is formed between the material pipeline and the insulation layer. Along the material flow direction, one end of the annular gap is provided with a fluid inlet and the other end is provided with a fluid outlet for the flow of high-temperature fluid.

[0015] A third aspect of the present invention provides the use of the conductive filler for cable shielding material produced by the above preparation method or the conductive filler for cable shielding material produced by the above production system in high-voltage submarine cables.

[0016] The present invention uses carbon black prepared by conventional methods, such as furnace carbon black as raw material. The carbon black raw material is first mixed with raw oil molecules, and then indirectly heated by high-temperature gas. A high heat exchange temperature and a short heat exchange time are controlled. A two-step method is used to achieve simultaneous improvement in the structure and graphitization degree of carbon black, especially furnace carbon black, which can meet the requirements of conductive fillers for cable shielding materials. The reason may be that the raw oil is carbonized during the high-temperature rapid heat exchange process, causing agglomeration between the carbon black raw materials, which can effectively increase the size of the carbon black aggregation structure. At the same time, the high temperature will also cause the crystal structure of the carbon black to change, thereby increasing the graphitization degree of the carbon black. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of a mixing unit in some embodiments of the present invention;

[0018] Figure 2 Schematic diagram of the structure of a high-temperature treatment device in some embodiments of the present invention.

[0019] Description of Reference Numerals

[0020] 1-mixing device, 101-spray inlet, 102-carbon black inlet, 103-stirring device,

[0021] 2-carbon black separation device, 201-excess gas outlet, 3-excess gas separation device, 4-material pipeline,

[0022] 401-mixed material inlet, 5-thermal insulation layer, 6-annular gap, 601-fluid inlet,

[0023] 602-fluid outlet, 7-heat exchange device, 8-cooling device, 9-collecting device. DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0025] A first aspect of the present invention provides a method for preparing a conductive filler for a cable shielding material, the method comprising:

[0026] S1, mixing the first solution containing the raw oil with the carbon black raw material in the form of a spray, and then cooling to obtain a mixed material; wherein the oil absorption value of the carbon black raw material is 160-220 (10 -5 m 3 / kg);

[0027] The aromatic content in the raw oil is 70-85wt%, and the asphaltene content is less than 0.1wt%;

[0028] S2. In the presence of a carrier gas, the mixed material flows in a heating section to perform indirect heat exchange with a high-temperature fluid;

[0029] The temperature of the high-temperature fluid is not lower than 1800° C., and the heat exchange time is 30-120 seconds.

[0030] In the present invention, the aromatic content in the feedstock oil is 70-85 wt %, for example, 70, 72, 75, 78, 80, 82, 85 wt %, or any range therebetween, preferably 75-80 wt %. Within this preferred range, sufficient carbon source can be provided for the second step of high-temperature agglomeration of carbon black. If the aromatic content is insufficient, the agglomeration effect will be poor.

[0031] Preferably, the asphaltene content in the feedstock oil is less than 0.1 wt %. Too high an asphaltene content will affect the atomization of the feedstock oil and produce too many hard carbon impurity particles under high temperature conditions.

[0032] The use of the feedstock oil with the preferred composition is beneficial to providing a high-quality carbon source for the reaction and reducing the generation of by-products in the reaction.

[0033] The present invention has no particular limitation on the source of the feedstock oil. For example, it can be any feedstock oil used in the art for preparing traditional furnace carbon black, and can be purchased commercially, as long as it meets the above-mentioned composition requirements. Preferably, it can be provided by ethylene tar and / or anthracene oil.

[0034] According to the present invention, the oil absorption value of the carbon black raw material is 160-220 (10 -5 m 3 / kg), preferably 180-200 (10 - 5 m 3 / kg).

[0035] In the present invention, the oil absorption value is tested according to the GB / T 3780.2-2017 method.

[0036] In the present invention, the Raman spectrum is used to D / I G The peak area ratio can reflect the degree of defects and disorder of carbon materials, where I D The peaks represent the defects and disorder in carbon materials, I G The peaks represent lattice vibration and order degree, and the ratio of the two can reflect the relative degree of graphitization. The smaller the ratio, the higher the degree of graphitization.

[0037] Preferably, the carbon black raw material I D / I G It is 1.8-2.0.

[0038] In the present invention, the Raman spectrum testing method includes: first, uniformly dispersing the sample on a silicon wafer, glass or aluminum foil substrate. To avoid agglomeration, ultrasonic dispersion can be performed and then drop-coated. A laser with a wavelength of 532 nm is selected for testing to obtain a Raman spectrum of the sample. The D peak (~1350 cm -1 ) and G peak (~1580 cm -1 ) The ratio of the intensity I D / I G It can be used to indicate the degree of graphitization of the sample.

[0039] According to some preferred embodiments of the present invention, the carbon black raw material is furnace black. Furnace black is a type of carbon black produced by incomplete combustion or pyrolysis of natural gas or high-aromatic oil in a dedicated reactor. The advantage of furnace black is that the degree of sintering or agglomeration of the primary carbon black particles can be adjusted according to different applications. During the production process of furnace black, quenching water is typically used to terminate the agglomeration of the primary carbon black particles. This method has the advantage of terminating the carbon black growth process in a very short time, maintaining a similar level of carbon black structure. However, conventional furnace black reactors do not have an external heat supply in the carbon black agglomeration stage. The entire driving force for carbon black growth comes from the large amount of waste heat generated by fuel combustion in the carbon black reactor. Therefore, even without quenching water to terminate the carbon black growth process, the carbon black growth will terminate within a very short time due to the large amount of heat dissipated by the device, causing the temperature to fall below the agglomeration temperature. However, the structure of the carbon black produced by natural cooling is often difficult to properly control. Therefore, due to the limitations of the reactor, the structure and degree of graphitization of furnace black cannot reach the performance level of superconducting carbon black or conductive fillers used in cable shielding materials.

[0040] The present invention adopts existing furnace carbon black as raw material to prepare conductive filler for cable shielding material, which is conducive to reducing the difficulty of preparing superconductive carbon black. The prepared conductive filler can meet the performance requirements of high-voltage cable shielding material.

[0041] According to some preferred embodiments of the present invention, the average particle size of the carbon black raw material is 20-60 nm. In the present invention, the average particle size of the particles refers to the primary particles of carbon black, that is, the particle size of a single carbon black ball.

[0042] In the present invention, the carbon black raw material is preferably carbon black that remains in its original state without any processing, generally in a fluffy powder state, also known as powdered carbon black.

[0043] According to some preferred embodiments of the present invention, the mass ratio of the first solution containing feedstock oil to the carbon black raw material is 0.1-10:1, preferably 0.5-2:1, and can be, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or any range therebetween. Controlling the amounts of the first solution and the carbon black raw material within the above preferred range is beneficial for more efficiently providing an effective carbon source for the carbon black while not causing excessive solvent usage, thereby reducing costs.

[0044] According to the present invention, preferably, the first solution containing the feedstock oil further contains an organic solvent. The present invention has a wide range of choices for the organic solvent. Preferably, the organic solvent is selected from at least one of benzene, toluene, xylene, ether, and acetone.

[0045] Further preferably, the mass ratio of the feedstock oil to the solvent is (0.1-1):100, for example, it can be 0.1:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100 or other specific mass ratios or any range therebetween.

[0046] In the present invention, the first solution containing the feedstock oil is mixed with the carbon black feedstock in the form of a spray, which can ensure uniform mixing of the feedstock oil molecules and the carbon black feedstock, so that the feedstock oil molecules are wrapped around the surface of the carbon black feedstock.

[0047] Preferably, in step S1, the mixing method includes spraying and atomizing a first solution containing feedstock oil, and then mixing the carbon black feedstock with the atomized first solution using a carrier gas. The present invention does not particularly limit the conditions for the spraying and atomizing, and is based on conditions that can achieve atomization of the first solution. Those skilled in the art may select the conditions based on actual needs.

[0048] In the case of the above-mentioned preferred concentration composition of the first solution, after the solution is atomized, the solvent will be vaporized and expanded due to heating, and the raw oil will be further dispersed. Therefore, in the above-mentioned preferred case, the requirements can be met by using conventional atomization methods and conditions.

[0049] According to some preferred embodiments of the present invention, the spray atomization is carried out using a conventional pressure atomizing nozzle, the aperture range of the nozzle is preferably 0.1-1 mm, and the working pressure is 0.5-5 MPa. When a small nozzle aperture and low working pressure are selected, the flow rate can also be increased by increasing the number of nozzles. Preferably, the flow rate of the solution is 1-20 mL / s.

[0050] According to the present invention, preferably, the mixing temperature in step S1 is 250-300°C, for example, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, or any range therebetween. Controlling the mixing temperature within this preferred range facilitates rapid vaporization of the solvent in the solution, more evenly dispersing the feedstock oil, and allowing for sufficient mixing with the carbon black, thereby improving the performance of the resulting conductive filler.

[0051] According to the present invention, step S1 further comprises subjecting the mixed product to gas-solid separation, collecting the solid product to obtain the mixed material. The gas phase stream obtained by the gas-solid separation can be optionally cooled to separate the carrier gas and organic solvent therein for reuse.

[0052] The present invention has a wide range of selection for the cooling conditions. Preferably, the cooling temperature in step S1 is 150-200°C.

[0053] In the present invention, it is understood that "indirect heat exchange" means that the mixed material and the high-temperature fluid are not in direct contact. The present invention does not particularly limit the manner in which the mixed material and the high-temperature fluid perform indirect heat exchange. For example, the mixed material can flow through a heating section formed in the pipe, and the high-temperature fluid performs indirect contact heat exchange outside the pipe. Preferably, the pipe can be a graphite tube, a high-temperature resistant ceramic tube, a tungsten tube, etc. The high-temperature resistant ceramic tube can be, for example, hafnium carbide ceramic, zirconium carbide ceramic, tantalum carbide ceramic, boron carbide ceramic, silicon carbide ceramic, or boron nitride ceramic. In addition to directly using high-temperature resistant ceramics, a high-temperature resistant ceramic coating can also be added to the outside of the carbon-based tube. The use of the above preferred method can further improve the efficiency of heat exchange.

[0054] The inventors of the present invention have found in their research that by allowing the mixed material to flow in a heating section and perform indirect heat exchange with a high-temperature fluid to achieve high-temperature and rapid heat treatment, the structure and degree of graphitization of carbon black, especially furnace carbon black, can be simultaneously improved.

[0055] According to the present invention, the temperature of the high-temperature fluid is not less than 1800°C, and preferably, the temperature of the high-temperature fluid is 1800-2200°C. In this preferred embodiment, the feedstock oil molecules serving as the carbon source are rapidly carbonized on the surface of the carbon black, and contacting carbon blacks are agglomerated, thereby achieving the growth of the carbon black structure. Simultaneously, the high temperature condition also provides a driving force for the conversion of amorphous carbon in the carbon black to crystalline carbon.

[0056] In the present invention, the heat exchange time is 30-120 seconds, preferably 30-90 seconds. The heat exchange time refers to the average time a stream of mixed material undergoes heat exchange in the heating section, with t0 being the time the mixed material begins to enter the heating section and t1 being the time the mixed material begins to flow out of the heating section. The heat exchange time is calculated as t1-t0. Controlling the heat exchange time within this preferred range further improves the structure and graphitization degree of furnace carbon black.

[0057] The present invention has no particular limitation on the type of the high-temperature fluid, as long as it can meet the temperature requirements, and can be, for example, an inert gas and / or liquid, which can be selected by those skilled in the art according to actual conditions. Preferably, the high-temperature fluid is argon.

[0058] According to some preferred embodiments of the present invention, the flow direction of the mixed material is opposite to the flow direction of the high-temperature fluid.

[0059] According to the present invention, preferably, the flow rate of the high temperature fluid is 0.1-10 L / s, preferably 2-5 L / s. The above preferred embodiment is conducive to further improving the efficiency of heat exchange.

[0060] Preferably, the flow rate of the mixed material is 0.1-5 g / s, preferably 1-2 g / s.

[0061] Preferably, in step S2, the flow rate of the carrier gas is 0.1-1 L / s, for example, it can be a specific flow rate value such as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 L / s, or any range between the two.

[0062] Controlling the flow rates of the mixed material and the carrier gas within the above preferred range can ensure a higher heat utilization rate while avoiding material sedimentation.

[0063] According to some preferred embodiments of the present invention, the preparation method further comprises subjecting the product obtained in step S2 to multi-stage cooling, comprising:

[0064] First, a first cooling is performed to 300-500°C, preferably 300-450°C; and then a second cooling is performed to 50-200°C, preferably 50-100°C.

[0065] The preferred multi-stage cooling method is advantageous for reusing excess heat, and the multi-stage cooling method can reduce the working pressure of the cooling device.

[0066] The present invention does not particularly limit the method of multi-stage cooling. Preferably, the first cooling is performed using a heat exchange device. For example, any one of a shell and tube heat exchanger, a plate heat exchanger, a spiral plate heat exchanger, a plate-fin heat exchanger, a sleeve heat exchanger, and an immersion heat exchanger can be used for heat exchange, so that the mixed gas serves as a hot fluid and the unheated carrier gas serves as a cold fluid. The two fluids exchange heat in the heat exchanger, and the heat of the mixed gas is transferred to the cold carrier gas, which is heated and the mixed gas is cooled. The second cooling can preferably be performed using one of an air cooler, an evaporative cooler, a spray cooling system, and a chiller. By using the above preferred embodiment, the heat of the mixed gas can be recovered and used to preheat the carrier gas.

[0067] A second aspect of the present invention provides a production system for a conductive filler for cable shielding materials, the production system comprising a carbon black raw material supply unit, a raw oil supply unit, a mixing unit, and a high-temperature treatment device;

[0068] The mixing unit includes a mixing device, a carbon black separation device and a residual gas separation device which are connected in sequence; the upper portion of the mixing device is provided with a spray inlet connected to the raw oil supply unit, and a carbon black inlet connected to the carbon black raw material supply unit;

[0069] The high-temperature treatment device includes a material pipeline and an insulation layer that are sheathed from the inside out. An annular gap is formed between the material pipeline and the insulation layer. Along the direction of material flow, one end of the annular gap is provided with a fluid inlet and the other end is provided with a fluid outlet to allow high-temperature fluid to flow and perform heat exchange on the material in the material pipeline.

[0070] In the present invention, the feedstock oil supply unit may include a feedstock oil storage tank and an organic solvent storage tank connected by a pipeline, for providing the first solution containing the feedstock oil.

[0071] like Figure 2 As shown, the material pipeline is provided with a heat insulation layer on the outside, and there is an annular gap between the material pipeline and the heat insulation layer. Both ends are sealed and have independent fluid inlets and outlets.

[0072] In the present invention, the spray inlet of the mixing device is preferably provided with a nozzle for atomizing the first solution containing the feedstock oil through the nozzle and then delivering it into the mixing device through the spray inlet. Preferably, the nozzle has an aperture range of 0.1-1 mm and an operating pressure of 0.5-5 MPa.

[0073] Preferably, the high-temperature fluid can be heated by an external heating device, which can adopt various methods such as fuel combustion heating or electric heating to achieve heating. The high-temperature fluid heated by the heating device enters from the fluid inlet at one end of the device and is discharged from the fluid outlet at the other end, then re-enters the heating device for heating and then returns to the high-temperature treatment device to form a cycle.

[0074] Preferably, the mixing device is provided with a stirring device, and the added raw materials are fully mixed by the rotation of the stirring device and then blown into the carbon black separation device.

[0075] Preferably, the feed port of the material pipeline is connected to the discharge port of the carbon black separation device, so as to feed the mixed material from the mixing unit into the high-temperature treatment device for indirect heat exchange.

[0076] Preferably, the system further comprises a carrier gas supply device, which provides carrier gas to the solid feed of the mixing unit and the high-temperature treatment device. Specifically, the carrier gas supply device can be connected via a pipeline to the carbon black inlet of the mixing device and any location on the connecting pipeline of the carbon black supply unit, and the carbon black raw material can be delivered to the mixing device using the carrier gas. Similarly, the carrier gas supply device can also be connected via a pipeline to any location between the feed inlet of the material pipeline and the discharge outlet of the carbon black separation device, and the mixed material can be delivered to the material pipeline using the carrier gas.

[0077] In the present invention, there is no particular limitation on the placement direction of the high temperature treatment device. Figure 2 As shown, the device can be placed horizontally. The device is easier to assemble in a horizontal position. In addition to horizontal placement, the device can also be placed at an angle of 0-90° to the ground. However, large angles, especially vertical placement, increase the difficulty of device assembly. However, by raising the inlet end of the mixed material, the gravity acting on the solid material inside the device can provide a component of force in the conveying direction. If the device is placed at 90°, the carbon black can theoretically be conveyed entirely by gravity. However, in actual application, in order to improve conveying efficiency and avoid material blockage, it is still necessary to use an inert gas or other carrier gas as the conveying gas.

[0078] Preferably, the high-temperature treatment device further comprises a heat exchange device and a cooling device which are sequentially connected to the discharge port of the material pipeline, and is used for performing segmented cooling on the discharge port of the material pipeline.

[0079] Preferably, the heat exchange device is connected to a carrier gas supply device and is used to preheat the carrier gas before returning it to the mixing device and / or the material pipeline. The mixed gas obtained at the outlet of the material pipeline serves as the hot fluid, and the unheated carrier gas serves as the cold fluid. The two fluids exchange heat in the heat exchanger, with the heat of the mixed gas being transferred to the cold carrier gas, thereby heating the cold carrier gas and cooling the mixed gas. For example, the heat exchange device can be any one of a shell and tube heat exchanger, a plate heat exchanger, a spiral plate heat exchanger, a plate-fin heat exchanger, a double-tube heat exchanger, and an immersion heat exchanger.

[0080] The cooling device can preferably be any one of an air cooler, an evaporative cooler, a spray cooling system, and a chiller.

[0081] The present invention does not specifically limit the material of the material conduit, as long as it is heat-resistant and does not introduce foreign impurities. For example, graphite, high-temperature-resistant ceramics, and tungsten tubes can be used. Examples of high-temperature-resistant ceramics include hafnium carbide ceramics, zirconium carbide ceramics, tantalum carbide ceramics, boron carbide ceramics, silicon carbide ceramics, and boron nitride ceramics. In addition to using high-temperature-resistant ceramics directly, carbon-based tubes can also be coated with high-temperature-resistant ceramics. Preferably, the material conduit in the high-temperature processing device is a graphite tube.

[0082] Preferably, the material pipeline has a length of 1.5-3 m and an inner diameter of 5-10 cm.

[0083] According to some specific embodiments of the present invention, the production system includes a carbon black raw material supply unit, a raw oil supply unit, a mixing unit and a high-temperature treatment device. When the conductive filler is produced using the above system, Figure 1 As shown, the first solution containing crude oil from the crude oil supply unit is blown into the mixing device 1 through the spray inlet 101 at the upper part of the mixing device 1, and the carbon black from the carbon black raw material supply unit is fed into the mixing device 1 through the carbon black inlet 102. The mixing device is provided with a stirring device 103, which is used to mix the above substances and then transport them to the carbon black separation device 2 at the lower part of the mixing unit for gas-solid separation. The residual gas is sent to the residual gas separation device 3 through the residual gas outlet 201 for separation and recovery. The obtained mixed material is sent to the high-temperature treatment device for indirect heat exchange with the high-temperature fluid. Figure 2 As shown, a carrier gas is used to deliver the mixed material into the material pipeline 4 through the mixed material inlet 401. A high-temperature fluid enters the annular gap 6 formed between the material pipeline 4 and the thermal insulation layer 5 through the fluid inlet 601, and then flows out through the fluid outlet 602. The high-temperature fluid circulates and performs heat exchange on the material in the material pipeline. The mixed material after heat exchange is then sent to the heat exchange device 7 for primary cooling, then to the cooling device 8 for secondary cooling, and finally to the collection device 9 for product collection.

[0084] The third aspect of the present invention provides the use of the conductive filler for cable shielding material produced by the preparation method described in the first aspect or the conductive filler for cable shielding material produced by the production system described in the second aspect in high-voltage submarine cables.

[0085] The conductive filler prepared by the preparation method provided by the present invention has a high structural degree and a high degree of graphitization, and can meet the requirements of cable shielding materials for high-voltage submarine cables.

[0086] The present invention will be described in detail below through examples.

[0087] Unless otherwise specified, the raw materials used in the following examples are all commercially available.

[0088] Example 1

[0089] The production system used includes a carbon black raw material supply unit, a raw oil supply unit, and Figure 1 The mixing unit shown and Figure 2 The high temperature processing device shown is placed vertically.

[0090] The oil absorption value is selected as 180 10 -5 m 3 Using 1 kg of powdered furnace carbon black (average particle size of 40 nm) as the raw material, a solution was prepared with ethylene tar (75 wt% aromatics, 0.05 wt% asphaltene) and toluene at a mass ratio of 0.5:100. The nozzle had a 0.2 mm aperture and an operating pressure of 2 MPa. The carbon black was blown into a mixing device at a rate of 2 g / s using argon at a flow rate of 1 L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 1:1, with argon assist at a flow rate of 1 L / s. The temperature in the mixing device was set at 200°C. The mixture was stirred uniformly using a stirring device, then cooled to approximately 150°C in a cooling device and collected by a filter bag in the carbon black collection device.

[0091] The collected mixed material is transported directly to the carbon black inlet of the high-temperature treatment unit by a conveyor, where it is blown into a graphite tube with preheated argon gas. The heating section of the graphite tube is 2 meters long and has an inner diameter of 5 cm. Argon gas at 2200°C is passed through the tube for heating. The argon flow rate within the tube is 0.1 L / s, and the mixed material is added at a rate of 1 g / s. During the gas transport within the graphite tube, the mixed material reacts with the high temperature. The average heat exchange time of the mixed material within the graphite tube is approximately 90 seconds. Finally, it is cooled to 450°C in a heat exchange unit and then to 80°C in a cooling unit before being collected in a filter bag in the collection unit.

[0092] Example 2

[0093] The production system used includes a carbon black raw material supply unit, a raw oil supply unit, and Figure 1 The mixing unit shown and Figure 2 The high temperature processing device shown is placed vertically.

[0094] The oil absorption value is selected as 180 10 -5 m 3 / kg of powdered furnace carbon black (average particle size of 40nm) was used as the raw material. Ethylene tar (75wt% aromatics content, 0.05wt% asphaltene content) and toluene were mixed in a 1:100 mass ratio to form a solution. The nozzle had a 0.2mm aperture and an operating pressure of 2MPa. The carbon black was blown into a mixing device at a rate of 2g / s using argon at a flow rate of 2L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 0.5:1, with argon assist at a flow rate of 2L / s. The temperature in the mixing device was set at 300°C. The mixture was stirred uniformly using a stirring device, then cooled to approximately 200°C in a cooling device and collected by a filter bag in the carbon black collection device.

[0095] The collected mixed material is transported directly to the carbon black inlet of the high-temperature treatment unit by a conveyor, where it is blown into a graphite tube using preheated argon gas. The heating section of the graphite tube is 2 meters long and has an inner diameter of 5 cm. Argon gas at 2000°C is passed through the tube for heating. The argon flow rate within the tube is 1 L / s, and the mixed material is added at a rate of 5 g / s. The mixed material reacts with the high temperature during its transport within the graphite tube, with an average heat exchange time of approximately 30 seconds. Finally, it is cooled to 400°C in a heat exchange unit and then to 75°C in a cooling unit before being collected in a filter bag in the collection unit.

[0096] Example 3

[0097] The production system used includes a carbon black raw material supply unit, a raw oil supply unit, and Figure 1 The mixing unit shown and Figure 2 The high temperature processing device shown is placed vertically.

[0098] The oil absorption value is selected as 180 10 -5 m 3Using 1 kg of powdered furnace carbon black (average particle size of 40 nm) as the raw material, a solution was prepared with ethylene tar (75 wt% aromatics, 0.05 wt% asphaltene) and toluene at a mass ratio of 0.1:100. The nozzle had a 0.2 mm aperture and an operating pressure of 2 MPa. The carbon black was introduced into a mixing device at a rate of 0.1 g / s using argon at a flow rate of 0.1 L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 2:1, with argon assist at a flow rate of 0.1 L / s. The temperature in the mixing device was set at 250°C. The mixture was stirred until uniformly mixed using a stirring device, then cooled to approximately 150°C in a cooling device and collected by a filter bag in the carbon black collection device.

[0099] The collected mixed material is transported directly to the carbon black inlet of the high-temperature treatment unit by a conveyor, where it is blown into a graphite tube with preheated argon gas. The heating section of the graphite tube is 2 meters long and has an inner diameter of 5 cm. Argon gas at 1800°C is passed through the tube for heating at a flow rate of 0.1 L / s. The mixed material is fed at a rate of 0.1 g / s. The mixed material reacts with the high temperature during its transport within the graphite tube, with an average heat exchange time of approximately 90 seconds. Finally, it is cooled to 300°C in a heat exchange unit and then to 50°C in a cooling unit before being collected in a filter bag in the collection unit.

[0100] Example 4

[0101] The production system used includes a carbon black raw material supply unit, a raw oil supply unit, and Figure 1 The mixing unit shown and Figure 2 The high temperature treatment device shown, wherein the high temperature treatment device is placed at 45 degrees to the ground (the entrance is at the top).

[0102] The oil absorption value is selected as 180 10 -5 m 3 Using 1 kg of powdered furnace carbon black (average particle size of 40 nm) as the raw material, a solution was prepared with ethylene tar (75 wt% aromatics, 0.05 wt% asphaltene) and toluene at a mass ratio of 0.1:100. The nozzle had a 0.2 mm aperture and an operating pressure of 2 MPa. The carbon black was introduced into a mixing device at a rate of 0.1 g / s using argon at a flow rate of 0.1 L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 5:1, with argon assist at a flow rate of 0.1 L / s. The temperature in the mixing device was set at 250°C. The mixture was stirred uniformly using a stirring device, then cooled to approximately 150°C in a cooling device and collected by a filter bag in the carbon black collection device.

[0103] The collected mixed material is transported directly to the carbon black inlet of the high-temperature treatment unit by a conveyor, where it is blown into a graphite tube with preheated argon gas. The heating section of the graphite tube is 2 meters long and has an inner diameter of 5 cm. Argon gas at 2200°C is passed through the tube for heating. The argon flow rate within the tube is 1 L / s, and the mixed material is added at a rate of 5 g / s. During the gas transport within the graphite tube, the mixed material reacts with the high temperature, with an average heat exchange time of approximately 30 seconds. Finally, it is cooled to 450°C in a heat exchange unit and then to 80°C in a cooling unit before being collected in a filter bag in the collection unit.

[0104] Example 5

[0105] The production system used includes a carbon black raw material supply unit, a raw oil supply unit, and Figure 1 The mixing unit shown and Figure 2 The high temperature treatment device shown is placed horizontally.

[0106] The oil absorption value is selected as 180 10 -5 m 3 / kg of powdered furnace carbon black (average particle size of 40nm) was used as the raw material. Ethylene tar (75wt% aromatics, 0.05wt% asphaltene) and toluene were mixed in a 1:100 mass ratio to form a solution. The nozzle had a 0.2mm aperture and an operating pressure of 2MPa. The carbon black was blown into a mixing device at a rate of 2g / s using argon at a flow rate of 2L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 1:1, with argon assist at a flow rate of 2L / s. The temperature in the mixing device was set at 300°C. The mixture was stirred uniformly using a stirring device, then cooled to approximately 200°C in a cooling device and collected by a filter bag in the carbon black collection device.

[0107] The collected mixed material is transported directly to the carbon black inlet of the high-temperature treatment unit by a conveyor, where it is blown into a graphite tube with preheated argon gas. The heating section of the graphite tube is 2 meters long and has an inner diameter of 5 cm. Argon gas at 1800°C is passed through the tube for heating at a flow rate of 0.1 L / s. The mixed material is fed at a rate of 0.1 g / s. The mixed material reacts with the high temperature during its transport within the graphite tube, with an average heat exchange time of approximately 90 seconds. Finally, it is cooled to 300°C in a heat exchange unit and then to 50°C in a cooling unit before being collected in a filter bag in the collection unit.

[0108] Example 6

[0109] The production system used includes a carbon black raw material supply unit, a raw oil supply unit, and Figure 1 The mixing unit shown and Figure 2The high temperature treatment device shown is placed horizontally.

[0110] The oil absorption value is selected as 180 10 -5 m 3 / kg of powdered furnace carbon black (average particle size of 40nm) was used as the raw material. Anthracene oil (aromatic content: 80wt%, asphaltene content: 0.1wt%) and acetone were mixed in a 0.1:100 mass ratio to form a solution. The nozzle had a 0.1mm aperture and an operating pressure of 4MPa. The carbon black was blown into a mixing device at a rate of 2g / s using argon at a flow rate of 2L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 10:1, with argon assist at a flow rate of 2L / s. The temperature in the mixing device was set at 300°C. The mixture was stirred until uniformly by a stirring device, then cooled to approximately 100°C by a cooling device and collected by a filter bag in the carbon black collection device.

[0111] The collected mixed material is transported directly to the carbon black inlet of the high-temperature treatment unit by a conveyor, where it is blown into a graphite tube with preheated argon gas. The graphite tube has a 2-meter-long heating section and an inner diameter of 5 cm. Argon gas at 2200°C is passed through the tube for heating at a flow rate of 0.1 L / s. The mixed material is fed at a rate of 1 g / s. The mixed material reacts with the high temperature during its transport within the graphite tube, with an average heat exchange time of approximately 90 seconds. Finally, it is cooled to 450°C in a heat exchange unit and then to 80°C in a cooling unit before being collected in a filter bag in the collection unit.

[0112] Example 7

[0113] The production system used includes a carbon black raw material supply unit, a raw oil supply unit, and Figure 1 The mixing unit shown and Figure 2 The high temperature processing device shown is placed vertically.

[0114] The oil absorption value is selected as 180 10 -5 m 3 Using 1 kg of powdered furnace carbon black (average particle size of 40 nm) as the raw material, a solution was prepared with coal tar (70 wt% aromatics, 0.1 wt% asphaltene) and toluene at a mass ratio of 0.5:100. The nozzle had a 0.1 mm aperture and an operating pressure of 5 MPa. The carbon black was blown into a mixing device at a rate of 2 g / s using argon at a flow rate of 1 L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 1:1, with argon assist at a flow rate of 1 L / s. The temperature in the mixing device was set at 200°C. The mixture was stirred uniformly using a stirring device, then cooled to approximately 150°C in a cooling device and collected by a filter bag in the carbon black collection device.

[0115] The collected mixed material is transported directly to the carbon black inlet of the high-temperature treatment unit by a conveyor, where it is blown into a graphite tube with preheated argon gas. The heating section of the graphite tube is 2 meters long and has an inner diameter of 5 cm. Argon gas at 2200°C is passed through the tube for heating at a flow rate of 0.1 L / s. The mixed material is fed at a rate of 1 g / s. The mixed material reacts with the high temperature during its transport within the graphite tube, with an average heat exchange time of approximately 90 seconds. Finally, it is cooled to 450°C in a heat exchange unit and then to 80°C in a cooling unit before being collected in a filter bag in the collection unit.

[0116] Example 8

[0117] The production system used includes a carbon black raw material supply unit, a raw oil supply unit, and Figure 1 The mixing unit shown and Figure 2 The high temperature treatment device shown is placed horizontally.

[0118] The oil absorption value is selected as 180 10 -5 m 3 Using 1 kg of powdered furnace carbon black (average particle size of 40 nm) as the raw material, a solution was prepared with ethylene tar (75 wt% aromatics, 0.05 wt% asphaltene) and toluene at a mass ratio of 0.5:100. The nozzle had a 0.2 mm aperture and an operating pressure of 2 MPa. The carbon black was blown into a mixing device at a rate of 2 g / s using argon at a flow rate of 1 L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 1:1, with argon assist at a flow rate of 1 L / s. The temperature in the mixing device was set at 200°C. The mixture was stirred uniformly using a stirring device, then cooled to approximately 150°C in a cooling device and collected by a filter bag in the carbon black collection device.

[0119] The collected mixed material is transported directly by a conveyor to the carbon black inlet of the high-temperature treatment unit, where it is blown into a graphite tube using preheated argon gas. The heating section of the graphite tube is 2 meters long and has an inner diameter of 5 cm. Argon gas at 2200°C is passed through the tube for heating at a flow rate of 0.1 L / s. The mixed material is fed at a rate of 5 g / s. During the gas transport within the graphite tube, the mixed material reacts with the high temperature, with an average heat exchange time of approximately 90 seconds. Finally, it is cooled to 450°C in a heat exchange unit and then to 80°C in a cooling unit before being collected in a filter bag in the collection unit. After long-term operation, the yield of finished carbon black per unit time was found to be decreasing. After stopping the unit and allowing the temperature to drop, it was discovered that the carbon black had settled in the graphite tube, partially blocking it.

[0120] Comparative Example 1

[0121] The oil absorption value is selected as 180 10 -5 m 3 / kg of powdered furnace carbon black (average particle size of 40nm) is used as raw material, without pretreatment, and is directly blown into the furnace by preheated argon gas. Figure 2 The graphite tube of the high-temperature treatment device shown is vertically positioned, with the heating section of the tube being 2 meters long and having an inner diameter of 5 cm. Argon gas at 2200°C is passed through the tube for heating at a flow rate of 0.1 L / s. Carbon black is added at a rate of 1 g / s. The carbon black reacts with the high temperature during gas transport within the graphite tube. The average heat exchange time of the mixture within the graphite tube is approximately 90 seconds. Finally, it is cooled to 450°C in the heat exchange device and then to 80°C in the cooling device before being collected in a filter bag in the collection device.

[0122] Comparative Example 2

[0123] The oil absorption value is selected as 180 10 -5 m 3 Using 1 kg of powdered furnace carbon black (average particle size of 40 nm) as the raw material, ethylene tar (75 wt% aromatics, 0.05 wt% asphaltene) and toluene at a mass ratio of 0.5:100 to form a solution. The carbon black and solution were directly mixed at a mass ratio of 1:1 without using a raw material mixing device. After thorough stirring, the mixture was dried and collected.

[0124] The collected mixed material is then blown into a graphite tube using preheated argon gas. The high-temperature treatment unit is positioned vertically, with a 2-meter-long heating section. The tube has an inner diameter of 5 cm and is heated by 2200°C argon gas flowing through it at a flow rate of 0.1 L / s. The mixed material is fed at a rate of 1 g / s. While being transported through the graphite tube, the mixed material reacts with the high temperatures. The average heat exchange time within the tube is approximately 90 seconds. Finally, the mixed material is cooled to 450°C in the heat exchange unit and then to 80°C in the cooling unit before being collected in a filter bag in the collection unit.

[0125] Comparative Example 3

[0126] The oil absorption value is selected as 180 10 -5 m 3Using 1 kg of powdered furnace carbon black (average particle size of 40 nm) as the raw material, a solution was prepared with ethylene tar (75 wt% aromatics content, 0.05 wt% asphaltene content) and toluene at a mass ratio of 0.5:100. The carbon black was introduced into a mixing device at a rate of 2 g / s using argon at a flow rate of 1 L / s. The solution and carbon black were then sprayed into the mixing device at a mass ratio of 1:1, with argon assist at a flow rate of 1 L / s. The temperature in the mixing device was set at 200°C. The mixture was stirred uniformly using a stirring device, then cooled to approximately 150°C in a cooling device and collected by a filter bag in the carbon black collection device.

[0127] The collected mixed material was placed in a graphite container and placed in a high-temperature furnace at 2200°C for 10 minutes before being taken out.

[0128] The oil absorption and Raman spectroscopy of the materials prepared in the above examples and comparative examples were measured, and the results are shown in Table 1. Commercially available superconductive carbon black (acetylene black) was used as a reference sample.

[0129] Table 1

[0130]

[0131] The results in Table 1 show that, by adopting the preparation method provided by the present invention, the structure and degree of graphitization of the conductive filler prepared using traditional furnace carbon black as raw material are greatly improved, and its performance is close to that of commercial acetylene carbon black. It can be considered that the conductive filler prepared in the example has the potential to be used as a superconductive carbon black filler.

[0132] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a conductive filler for cable shielding material, characterized in that: The preparation method comprises: S1, mixing the first solution containing the raw material oil with the carbon black raw material in the form of a spray to obtain a mixed material; wherein the oil absorption value of the carbon black raw material is 160-220·10 -5 m 3 / kg; the mixing temperature is 250-300°C; The aromatic content in the raw oil is 70-85wt%, and the asphaltene content is less than 0.1wt%; S2. In the presence of a carrier gas, the mixed material flows in a heating section to perform indirect heat exchange with a high-temperature fluid; the flow rate of the mixed material is 1-5 g / s; The temperature of the high-temperature fluid is 1800-2200° C., and the heat exchange time is 90-120 seconds.

2. The preparation method according to claim 1, wherein The aromatics content in the raw oil is 75-80 wt%, and the asphaltene content is less than 0.1 wt%.

3. The preparation method according to claim 1, wherein The carbon black raw material is furnace carbon black; The oil absorption value of the carbon black raw material is 180-220·10 -5 m 3 / kg, I D / I G is 1.8-2.

4. The preparation method according to any one of claims 1 to 3, wherein The mass ratio of the first solution containing the raw material oil to the carbon black raw material is 0.1-10:

1.

5. The preparation method according to any one of claims 1 to 3, wherein The first solution containing the feedstock oil further contains an organic solvent, wherein the organic solvent is selected from at least one of benzene, toluene, xylene, ether and acetone; The mass ratio of raw oil to organic solvent is (0.1-1):

100.

6. The preparation method according to any one of claims 1 to 3, wherein In step S1, the mixing method includes: The first solution containing the raw material oil is sprayed and atomized, and then the carbon black raw material is mixed with the atomized first solution using a carrier gas.

7. The preparation method according to any one of claims 1 to 3, wherein The high-temperature fluid is an inert gas or liquid.

8. The preparation method according to claim 7, wherein The high-temperature fluid is argon.

9. The preparation method according to any one of claims 1 to 3, wherein The flow direction of the mixed material is opposite to the flow direction of the high-temperature fluid.

10. The preparation method according to any one of claims 1 to 3, wherein The preparation method further comprises subjecting the product obtained in step S2 to multi-stage cooling, comprising: The first cooling is performed to 300-500°C, and then the second cooling is performed to 50-200°C.

11. A production system for a conductive filler for cable shielding material used in the method for preparing a conductive filler for cable shielding material according to any one of claims 1 to 10, characterized in that: The production system includes a carbon black raw material supply unit, a raw oil supply unit, a mixing unit and a high-temperature treatment device; The mixing unit includes a mixing device, a carbon black separation device and a residual gas separation device which are connected in sequence; the upper portion of the mixing device is provided with a spray inlet connected to the raw oil supply unit, and a carbon black inlet connected to the carbon black raw material supply unit; The high-temperature treatment device includes a material pipeline and an insulation layer arranged from the inside to the outside, and an annular gap is formed between the material pipeline and the insulation layer. Along the material flow direction, one end of the annular gap is provided with a fluid inlet and the other end is provided with a fluid outlet to allow high-temperature fluid to flow and perform heat exchange on the material in the material pipeline.

12. The production system according to claim 11, wherein: The high-temperature treatment device also includes a heat exchange device and a cooling device which are sequentially connected to the discharge port of the material pipeline and are used to perform segmented cooling on the discharge port of the material pipeline.

13. The production system according to claim 11 or 12, wherein: The material pipeline in the high temperature treatment device is at least one of a graphite tube, a high temperature resistant ceramic tube and a tungsten tube; The material pipeline has a length of 1.5-3 m and an inner diameter of 5-10 cm.

14. Use of the conductive filler for cable shielding material prepared by the preparation method according to any one of claims 1 to 10 in high-voltage submarine cables.

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