WO2020172942A1

WO2020172942A1 - Device and method for modifying polypropylene-based insulating material for high-voltage direct-current cable

Info

Publication number: WO2020172942A1
Application number: PCT/CN2019/080312
Authority: WO
Inventors: 杜伯学; 侯兆豪; 李忠磊; 李进; 许然然; 韩晨磊
Original assignee: 天津大学
Priority date: 2019-02-27
Filing date: 2019-03-29
Publication date: 2020-09-03

Abstract

Disclosed is a device for modifying a polypropylene-based insulating material for a high-voltage direct-current cable, comprising a reaction kettle, a heating device, a stirring device, a computer control unit, and a suction filtration recovery device. The computer control unit is signally-connected to the heating device, the stirring device, and the suction filtration recovery device, and sends instructions to control a process flow. A heating control unit receives a temperature control instruction issued by the computer control unit and temperature feedback information from a thermocouple sensor, and controls the on/off state of a power supply of a resistance heating wire. Further disclosed is a modification method, comprising: first, placing a polypropylene composite base material and an organic solvent into the reaction kettle; turning on the heating device to heat up the polypropylene composite base material and the organic solvent in the reaction kettle and maintaining that state; stirring; adding a crosslinking agent accounting for 1% to 3% of the total mass of polyvinyl and octavinyl POSS into the reaction kettle and stirring for 5 to 10 minutes; and lowering the temperature and recycling. The organic solvent of the present invention has low toxicity and is produced in an enclosed environment, and can be recycled, providing excellent economic and environmental benefits.

Description

Polypropylene-based insulating material modification device and method for high-voltage DC cables

Technical field

The invention belongs to the technical field of high-voltage direct current transmission equipment, and specifically relates to a modification device and method of polypropylene-based high-voltage cable insulating materials.

Background technique

In recent years, high-voltage power transmission technology has achieved world-renowned development. As a key equipment of DC power transmission technology, high-voltage DC cables are used in island power transmission, ocean resource development and utilization, urban power grid transformation and upgrading, distributed energy grid-connected power transmission, etc. The development of China has important strategic significance. At present, the widely used cross-linked polyethylene cable has a working temperature of only 70°C and cannot be recycled after reaching its working life. In recent years, polypropylene-based cable insulation materials that can be recycled and reused have received extensive attention from domestic and foreign researchers and cable manufacturers. Polypropylene material not only has excellent dielectric properties, but also has a higher melting point. The development and application of these two properties will help improve the operating temperature, voltage and line current carrying capacity of polypropylene cables, and the application prospects are huge.

Under the high-voltage direct current electric field, on the one hand, the injection and accumulation of space charge in the polymer insulating material of the cable causes local electric field distortion in the insulating medium, accelerates the insulation aging, reduces the dielectric strength, and can cause insulation breakdown in severe cases. On the other hand, the current flowing through the cable under high voltage level is very large, and the heat generated by the core makes the cable run at a higher temperature for a long time. The conductivity of the insulating material at high temperature becomes larger and further aggravates the injection, migration and space charge. Aging of insulation. Therefore, improving the space charge characteristics of insulating materials is of great significance for the safe operation of high-voltage DC cables and large-capacity power transmission.

In recent years, nanomaterials have developed rapidly, and the size effect and interface effect of nanomaterials have a significant impact on the performance of nanocomposites. At present, the methods to improve the space charge characteristics of polypropylene insulating materials mostly adopt simple mechanical blending modification of nanoparticles directly with polypropylene matrix materials. However, due to the characteristics of nano-particles that are easy to agglomerate and difficult to uniformly disperse, especially in actual industrial production, there are disadvantages of large feeding amount and inadequate mixing, which more easily leads to deterioration of the space charge performance of polypropylene nanocomposite insulating materials. Therefore, how to improve the dispersion and interface compatibility of nanoparticles in polypropylene matrix materials, and then improve the space charge characteristics of polypropylene-based insulating materials for high-voltage DC cables, has important application value.

Summary of the invention

In order to overcome the shortcomings of the prior art, the present invention aims to provide a polypropylene-based insulating material modification device and method for high-voltage DC cables.

To this end, the technical solution adopted by the present invention is: a polypropylene-based insulating material modification device for high-voltage DC cables, including a reactor, a heating device, and a stirring device, as well as a computer control unit and a suction filter recovery device;

Wherein, the computer control unit signally connects the heating device, the stirring device, and the suction recovery device, sends instructions, and then controls the process flow;

Wherein, the heating device is composed of a heating control unit, a thermocouple sensor, a resistance heating wire, and a heat-resistant insulating layer. The heating control unit receives temperature control instructions from the computer control unit, temperature feedback information from the thermocouple sensor, and control resistance. The power supply of the heating wire is on and off, and the thermocouple sensor is located in the reaction kettle, and the resistance heating wire is evenly surrounded by the heat-resistant insulating layer;

Wherein, the suction filtration recovery device is composed of a condensing unit, a vacuum pump, a recovery tank, and a waste gas treatment tank; wherein, the condensing unit is composed of a condensation control unit, a refrigerator, a heat transfer oil, a circulating pump, and a condensing pipe, forming a closed loop circuit; wherein, The waste gas treatment tank contains activated carbon and has an opening; among them, the reaction kettle, the condensation unit, the recovery tank, the vacuum pump, and the waste gas treatment tank are connected in sequence through a hollow pipe.

The stirring device is composed of a motor control and drive unit, a motor and a stirring rod; wherein the motor control and drive unit receives a rotational speed control command issued by the computer control unit to drive the motor, and the stirring rod passes through the sealing cover of the reactor.

The reaction kettle is composed of an inner liner and a sealing cover.

The polypropylene composite base material, organic solvent, and crosslinking agent are fully mixed and reacted in a reaction kettle with pressure resistance, heating and stirring functions to obtain a nano-modified polypropylene-based composite insulating material.

The second technical scheme of the present invention is a method for modifying polypropylene-based insulating materials for high-voltage DC cables. The above-mentioned modification device is used to combine the polypropylene composite base material, organic solvent, and crosslinking agent with pressure resistance, heating, The fully mixed and reacted reaction kettle with stirring function obtains the nano-modified polypropylene-based composite insulating material, which specifically includes the following steps:

(1) Feeding: Put the polypropylene composite base material and organic solvent into the reactor;

The polypropylene composite base material is made by mixing polypropylene, octavinyl POSS, and antioxidants, wherein polypropylene and octaethylene

The mass ratio of alkenyl POSS is 4:1 to 5:1, and the antioxidant accounts for 1% to 5% of the total mass of polypropylene and octavinyl POSS;

(2) Heating: Turn on the heating device to heat up and maintain the polypropylene composite base material and organic solvent in the reactor;

The heating temperature is selected to be 5-10 degrees Celsius lower than the boiling point of the organic solvent used;

(3) Stirring: Turn on the stirring device so that the polypropylene composite base material in the reactor is fully dissolved in the organic solvent, and the stirring speed is constant and maintained;

(4) Grafting reaction: 1% to 3% of the total mass of polypropylene and octavinyl POSS is put into the reactor, and the stirring and heating device is stopped after stirring for 5 to 10 minutes;

(5) Cooling recovery: After the temperature in the reactor is cooled down, the suction filtration recovery device is turned on to suction filtration, gasification, and condensation of the organic solvent in the reactor to obtain pure organic solvent and modified polypropylene-based composite insulation. material;

The cooling temperature is 20-30 degrees Celsius lower than the boiling point of the organic solvent used.

In the step (1), polypropylene includes isotactic polypropylene, syndiotactic polypropylene or a blend of both;

Octavinyl-POSS, its CAS number is 69655-76-1, and the molecular formula is C16H24O12Si8;

Antioxidants include antioxidant 1010, antioxidant 1076, antioxidant 618, antioxidant 626, antioxidant 300, antioxidant 1035, and mixtures thereof.

The organic solvent in the step (2) includes toluene (CAS No. 108-88-3, molecular formula is C7H8), xylene (CAS No. 1330-20-7, molecular formula is C8H10), isoamyl acetate (CAS No. 123-92-2, molecular formula is C7H14O2), decalin (CAS No. 91-17-8, chemical formula is C10H18), the volume ratio of its input (calculated by L) is the mass of polypropylene composite base material (according to kg) 5 to 6 times.

The stirring speed in the step (3) is set at 30-50 r/min.

In the step (4), the crosslinking agent includes dicumyl peroxide (chemical formula is C18H22O2, CAS number is 80-43-3), dibenzoyl peroxide (molecular formula is C14H10O4, CAS number is 94-36- 0), vulcanizing agent double 25 (molecular formula is C16H34O4, CAS number is 78-63-7).

Compared with the prior art, the present invention has the following advantages:

(1) Nano particles can be uniformly dispersed in the polypropylene-based composite insulating material, and the compatibility between nano and polypropylene is better, and an insulating material for high-voltage DC cables with excellent performance can be prepared.

(2) Organic solvents are low in toxicity, are produced in a closed manner, and can be recycled and reused, with excellent economic and environmental benefits.

(3) The process equipment is easy to realize, the process is clear and easy to control, the temperature, speed, air pressure and other parameters in the production process are low in risk, and the operability and feasibility are excellent.

Description of the drawings

Figure 1 is a flowchart of the modification method of polypropylene-based insulating materials for high-voltage DC cables;

Figure 2 is a polypropylene-based insulating material modification device for HVDC cables.

Attached drawings: 1-computer control unit, 2-inner tank, 3-sealed cover, 4-heating control unit, 5-resistance heating wire, 6-thermocouple sensor, 7-heat-resistant insulation layer, 8-motor control and Drive unit, 9-motor, 10-stirring rod, 11-condensation control unit, 12-circulation pump, 13-refrigerator, 14-heat conduction oil, 15-condensation tube, 16-recovery tank, 17-vacuum pump, 18-exhaust gas Processing tank.

detailed description:

The present invention will be further described in detail below in conjunction with the examples and drawings, but the implementation of the present invention is not limited thereto.

Example 1

First put polypropylene (Hainan Petrochemical, PPH-T03), octavinyl POSS (Zhengzhou Alpha Chemical Co., Ltd.), antioxidant 1010 (Germany BASF) into the reactor at a mass ratio of 80:20:1, and the volume The proportion (calculated by L) of the xylene organic solvent accounting for 5 times the mass of the polypropylene composite base material (calculated by Kg) is put into the reactor. Turn on the heating device to raise the temperature of the polypropylene composite base material and the organic solvent in the reactor to 125 degrees Celsius and maintain it. Turn on the stirring device to fully dissolve the polypropylene composite base material in the reactor in the organic solvent, and keep the stirring speed constant at 30r/min. The cross-linking agent dicumyl oxide, which accounts for 1% of the total mass of polypropylene and octavinyl POSS, was put into the reactor, and after stirring for 5 minutes, the stirring and heating device was stopped. After the temperature in the reactor drops to 110 degrees Celsius, the suction filtration recovery device is turned on to suction filtration, gasification, and condensation of the organic solvent in the reactor to obtain pure organic solvents and modified polypropylene-based composite insulating materials.

Example 2

First put polypropylene (Hainan Petrochemical, PPH-T03), octavinyl POSS (Zhengzhou Alpha Chemical Co., Ltd.), antioxidant 1076 (Germany BASF) into the reactor at a mass ratio of 90:16:2, and the volume The proportion (calculated by L) of the organic solvent toluene, accounting for 5.5 times the mass of the polypropylene composite base material (calculated by Kg), is put into the reactor. Turn on the heating device to raise the temperature of the polypropylene composite base material and the organic solvent in the reactor by 100 degrees Celsius and keep it. Turn on the stirring device so that the polypropylene composite base material in the reactor is fully dissolved in the organic solvent, and the stirring speed is constant and maintained at 35r/min. The crosslinking agent dicumyl oxide, which accounts for 1.5% of the total mass of polypropylene and octavinyl POSS, was put into the reaction kettle, and after stirring for 5 minutes, the stirring and heating device was stopped. After the temperature in the reactor drops to 90 degrees Celsius, the suction filtration recovery device is turned on to suction filtration, gasification, and condensation recovery of the organic solvent in the reactor to obtain pure organic solvents and modified polypropylene-based composite insulating materials.

Example 3

First, polypropylene (Hainan Petrochemical, PPH-T03), octavinyl POSS (Zhengzhou Alpha Chemical Co., Ltd.), antioxidant 1010 (Germany BASF) and antioxidant 618 (Germany BASF) are compared by mass to 80:20 : 1.5:1.5 Put into the reaction kettle, and put the isoamyl acetate organic solvent whose volume ratio (in L) accounts for 6 times the mass of the polypropylene composite base material (in Kg) into the reaction kettle. Turn on the heating device to raise the temperature of the polypropylene composite base material and the organic solvent in the reactor to 130 degrees Celsius and maintain it. Turn on the stirring device to fully dissolve the polypropylene composite base material in the reactor in the organic solvent, and keep the stirring speed constant at 30r/min. The crosslinking agent dibenzoyl peroxide, which accounts for 3% of the total mass of polypropylene and octavinyl POSS, was put into the reactor, and after stirring for 6 minutes, the stirring and heating device was stopped. After the temperature in the reactor drops to 120 degrees Celsius, the suction filtration recovery device is turned on to suction filtration, gasification, and condensation recovery of the organic solvent in the reactor to obtain pure organic solvents and modified polypropylene-based composite insulating materials.

Example 4

First, polypropylene (Hainan Petrochemical, PPH-T03), octavinyl POSS (Zhengzhou Alpha Chemical Co., Ltd.), antioxidant 626 (Germany BASF) and antioxidant 1035 (Germany BASF) are compared by mass ratio of 90:16 : 2.5:2.5 Put into the reaction kettle, and put the isoamyl acetate organic solvent with the volume ratio (in L) accounting for 5 times the mass of the polypropylene composite base material (in Kg) into the reaction kettle. Turn on the heating device to raise the temperature of the polypropylene composite base material and the organic solvent in the reactor to 130 degrees Celsius and maintain it. Turn on the stirring device so that the polypropylene composite base material in the reactor is fully dissolved in the organic solvent, and the stirring speed is constant and maintained at 30r/min. The crosslinking agent dibenzoyl peroxide, which accounts for 3% of the total mass of polypropylene and octavinyl POSS, was put into the reactor, and after stirring for 6 minutes, the stirring and heating device was stopped. After the temperature in the reactor drops to 120 degrees Celsius, the suction filtration recovery device is turned on to suction filtration, gasification, and condensation recovery of the organic solvent in the reactor to obtain pure organic solvents and modified polypropylene-based composite insulating materials.

Example 5

First, polypropylene (Hainan Petrochemical, PPH-T03), octavinyl POSS (Zhengzhou Alpha Chemical Co., Ltd.), and antioxidant 300 (BASF, Germany) are put into the reactor at a mass ratio of 80:20:5, and the volume The ratio (calculated by L) of the organic solvent of decalin, which accounts for 6 times the mass of the polypropylene composite base material (calculated by Kg), is put into the reactor. Turn on the heating device to increase the temperature of the polypropylene composite base material and the organic solvent in the reactor at 175 degrees Celsius and maintain it. Turn on the stirring device to fully dissolve the polypropylene composite base material in the reactor in the organic solvent, and keep the stirring speed constant at 30r/min. Put 2% of the total mass of polypropylene and octavinyl POSS crosslinking agent vulcanizing agent Double 25 into the reactor, and after stirring for 6 minutes, stop the stirring and heating device. After the temperature in the reactor drops to 160 degrees Celsius, the suction filtration recovery device is turned on to suction filtration, gasification, and condensation recovery of the organic solvent in the reactor to obtain pure organic solvents and modified polypropylene-based composite insulating materials.

The process flow of the present invention is shown in Figure 1.

As shown in Figure 2, the present invention uses a set of polypropylene-based insulating material modification device for high-voltage DC cables, which is composed of a computer control unit, a reactor, a heating device, a stirring device and a suction filter recovery device.

Among them, the computer control unit 1 has a man-machine interactive interface function and a communication function; the man-machine interactive interface function can set material parameters, heating temperature, stirring speed, vacuum filtration air pressure, condensation temperature, etc.); among them, the communication function It can send instructions to the heating device, stirring device, and suction filter recovery device to control the process flow.

Wherein, the reaction kettle is composed of a cylindrical stainless steel liner 2 and a stainless steel sealing cover 3, and has a vacuum tightness and an atmospheric pressure resistance of 10 MPa.

Wherein, the heating device is composed of a heating control unit 4, a thermocouple sensor 6, a resistance heating wire 5, and a heat-resistant insulating layer 7. The heating control unit can receive temperature control instructions issued by the computer control unit 1, and the thermocouple sensor 6 The temperature feedback information for controlling the power supply of the resistance heating wire 5 is turned on and off. The thermocouple sensor 6 is located in the reaction kettle, and the resistance heating wire 5 evenly surrounds the reaction kettle and is covered by a heat-resistant insulating layer.

Wherein, the stirring device is composed of a motor control and drive unit 8, a motor 9 and a stirring rod 10; wherein the motor control and drive unit 8 can receive a speed control command issued by the computer control unit 1 to drive the motor 9 and the stirring rod 10. To pass through the reaction kettle stainless steel sealing cover 3.

The suction filtration recovery device is composed of a condensing unit, a vacuum pump 17, a recovery tank 16, and a waste gas treatment tank 18. The condensing unit is composed of a condensing control unit 11, a refrigerator 13, a heat transfer oil 14, a circulation 12 pump, and a condensing pipe 15 composition, forming a closed loop; among them, the waste gas treatment tank 18 contains activated carbon and has an opening; among them, the reaction kettle, the condensation unit, the recovery tank, the vacuum pump, and the waste gas treatment tank are connected in sequence by a stainless steel hollow pipe.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, etc. made without departing from the spirit and principle of the present invention Simplified, all should be equivalent replacement methods, which are all included in the protection scope of the present invention.

Claims

A polypropylene-based insulating material modification device for high-voltage DC cables, comprising a reactor, a heating device and a stirring device, and is characterized in that it also includes a computer control unit and a suction filter recovery device;

Wherein, the computer control unit signally connects the heating device, the stirring device, and the suction recovery device, sends instructions, and then controls the process flow;

Wherein, the heating device is composed of a heating control unit, a thermocouple sensor, a resistance heating wire, and a heat-resistant insulating layer. The heating control unit receives temperature control instructions from the computer control unit, temperature feedback information from the thermocouple sensor, and control resistance. The power supply of the heating wire is on and off, and the thermocouple sensor is located in the reaction kettle, and the resistance heating wire is evenly surrounded by the heat-resistant insulating layer;

Wherein, the suction filtration recovery device is composed of a condensing unit, a vacuum pump, a recovery tank, and a waste gas treatment tank; wherein, the condensing unit is composed of a condensation control unit, a refrigerator, a heat transfer oil, a circulating pump, and a condensing pipe, forming a closed loop circuit; wherein, The waste gas treatment tank contains activated carbon and has an opening; among them, the reaction kettle, the condensation unit, the recovery tank, the vacuum pump, and the waste gas treatment tank are connected in sequence through a hollow pipe.
The polypropylene-based insulating material modification device for high-voltage DC cables according to claim 1, wherein the stirring device is composed of a motor control and drive unit, a motor and a stirring rod; wherein the motor control and drive unit receives The speed control command issued by the computer control unit drives the motor, and the stirring rod passes through the sealing cover of the reactor.
The polypropylene-based insulating material modification device for high-voltage DC cables according to claim 1, wherein the reaction kettle is composed of an inner liner and a sealing cover.
A method for modifying polypropylene-based insulating materials for high-voltage DC cables, using the modification device according to any one of claims 1 to 3, characterized in that the polypropylene composite base material, organic solvent, and crosslinking agent are mixed in Fully mixed and reacted in a reactor with pressure resistance, heating, and stirring functions to obtain a nano-modified polypropylene-based composite insulating material, which specifically includes the following steps:

(1) Feeding: Put the polypropylene composite base material and organic solvent into the reactor;

The polypropylene composite base material is a mixture of polypropylene, octavinyl POSS, and antioxidant, wherein the mass ratio of polypropylene to octavinyl POSS is 4:1 to 5:1, and the antioxidant accounts for polypropylene and 1% to 5% of the total mass of eight vinyl POSS;

(2) Heating: Turn on the heating device to heat up and maintain the polypropylene composite base material and organic solvent in the reactor;

The heating temperature is selected to be 5-10 degrees Celsius lower than the boiling point of the organic solvent used;

(3) Stirring: Turn on the stirring device so that the polypropylene composite base material in the reactor is fully dissolved in the organic solvent, and the stirring speed is constant and maintained;

(4) Grafting reaction: 1% to 3% of the total mass of polypropylene and octavinyl POSS is put into the reactor, and the stirring and heating device is stopped after stirring for 5 to 10 minutes;

(5) Cooling and recovery: After the temperature in the reactor is cooled, the suction filtration recovery device is turned on to suction filtration, gasification, and condensation of the organic solvent in the reactor to obtain pure organic solvent and modified polypropylene-based composite insulation. material;

The cooling temperature is 20-30 degrees Celsius lower than the boiling point of the organic solvent used.
The method for modifying polypropylene-based insulating materials for high-voltage DC cables according to claim 1, wherein the polypropylene in the step (1) comprises isotactic polypropylene, syndiotactic polypropylene or a blend of both Thing

Eight vinyl-POSS;

Antioxidants include antioxidant 1010, antioxidant 1076, antioxidant 618, antioxidant 626, antioxidant 300, antioxidant 1035, and mixtures thereof.
The method for modifying polypropylene-based insulating materials for high-voltage DC cables according to claim 1, wherein the organic solvents in step (2) include toluene, xylene, isoamyl acetate (CAS number: 123-92-2, the molecular formula is C7H14O2), decalin, the volume ratio (calculated by L) of which is 5-6 times the mass of the polypropylene composite base material (calculated by kg).
The method for modifying polypropylene-based insulating materials for high-voltage DC cables according to claim 1, wherein the stirring speed in the step (3) is set at 30-50 r/min.
The method for modifying polypropylene-based insulating materials for high-voltage DC cables according to claim 1, wherein the crosslinking agent in the step (4) includes dicumyl peroxide, dibenzoyl peroxide , Vulcanizing agent double 25.