WO2022166175A1 - Carbon nanotube preparation device and method using spark-ignition dual-fuel engine - Google Patents

Carbon nanotube preparation device and method using spark-ignition dual-fuel engine Download PDF

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Publication number
WO2022166175A1
WO2022166175A1 PCT/CN2021/114563 CN2021114563W WO2022166175A1 WO 2022166175 A1 WO2022166175 A1 WO 2022166175A1 CN 2021114563 W CN2021114563 W CN 2021114563W WO 2022166175 A1 WO2022166175 A1 WO 2022166175A1
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cylinder
exhaust gas
carbon nanotube
valve
carbon nanotubes
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PCT/CN2021/114563
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French (fr)
Chinese (zh)
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毛功平
毛欢
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江苏大学
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/08—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed simultaneously using pluralities of fuels
    • F02D19/082—Premixed fuels, i.e. emulsions or blends
    • F02D19/084—Blends of gasoline and alcohols, e.g. E85
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/022—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D45/00—Electrical control not provided for in groups F02D41/00 - F02D43/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/52—Systems for actuating EGR valves
    • F02M26/53—Systems for actuating EGR valves using electric actuators, e.g. solenoids
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

Definitions

  • the invention belongs to the technical field of material preparation, and in particular relates to a carbon nanotube preparation device and method using an ignition type dual-fuel engine.
  • carbon nanotubes are widely used in high-strength materials, sensors, nanoelectronics, energy storage, catalyst supports, biological It has a very broad application prospect in medicine and other fields. From the discovery of carbon nanotubes in 1991 to the present, scholars at home and abroad have done a lot of research on carbon nanotubes, and have achieved rich results in their preparation and application. For the preparation of carbon nanotubes, there are quite mature methods: arc discharge method, chemical vapor deposition method, laser evaporation method and flame method. The first three methods all require additional energy supply, which increases energy consumption and costs. Gao, in order to solve this problem, the flame method came into being. The flame method is a new preparation method of carbon nanotubes that has been gradually developed in the past two decades.
  • the flame method also has shortcomings such as many impurities, involving dangerous gases and producing harmful polluting gases, so it has a lot of room for improvement and optimization.
  • the present invention provides a carbon nanotube preparation device and method using an ignition type dual-fuel engine, so as to realize the high-purity, low-pollution, continuous mass production of carbon nanotubes.
  • the present invention achieves the above technical purpose through the following technical means.
  • a carbon nanotube preparation device using an ignition type dual-fuel engine comprising a natural gas storage cylinder and a gasoline tank;
  • the natural gas storage cylinder is communicated with the air inlet of the cylinder through a pipeline, and a jet valve is provided at the connection between the natural gas storage cylinder and the air inlet; a throttle valve is arranged on the air inlet of the cylinder; A carbon nanotube trap, an EGR valve and an exhaust gas analyzer are arranged in sequence in the gas direction, and the exhaust pipe is connected to the intake port through a pipeline where the EGR valve is set;
  • the gasoline tank is communicated with a fuel injector arranged on the cylinder through a pipeline, and a stop valve is provided on the pipeline of the gasoline tank;
  • the top of the cylinder is provided with a spark plug and a cylinder pressure sensor
  • the jet valve, throttle valve, exhaust gas analyzer, EGR valve, spark plug, and cylinder pressure sensor are all signal-connected to the electronic control unit, and the signals also received by the electronic control unit include: oxygen content in the exhaust, exhaust temperature, throttle valve opening, engine speed, exhaust back pressure and engine in-cylinder pressure.
  • electromagnets and filters are respectively arranged at both ends of the carbon nanotube trap, and electromagnet coils are wound around the electromagnets, and the electromagnet coils arranged on adjacent electromagnets are different;
  • electromagnet coils arranged on adjacent electromagnets are different;
  • cuboid-shaped ceramic hole plugs are arranged inside, and the adjacent ceramic hole plugs arranged inside the filter are different.
  • an exhaust gas turbine and a three-way catalytic converter are also provided on the exhaust pipe of the cylinder, and the exhaust gas turbine is located between the exhaust gas analyzer and the EGR valve, and the exhaust gas analyzer is located between the exhaust gas turbine and the three-way catalytic converter. between the devices.
  • an air filter, a compressor and an intercooler are arranged on the intake passage of the cylinder in sequence along the intake direction, and the compressor is connected with the exhaust gas turbine.
  • a gasoline filter and a fuel pump are also arranged in sequence between the fuel injector and the fuel tank along the fuel inlet direction.
  • a natural gas filter and a pressure regulator are arranged in sequence along the air intake direction between the natural gas storage cylinder and the jet valve.
  • a method for preparing carbon nanotubes using an ignition type dual-fuel engine specifically:
  • the natural gas and fresh air are mixed and injected into the cylinder, and the gasoline mixed with the catalyst is also injected into the cylinder.
  • the gasoline mixed with the catalyst is also injected into the cylinder.
  • the consumption ratio of the natural gas to gasoline is 0.4-0.5, the catalyst is 7000ppm oil-soluble iron oxide nanoparticles, and the natural gas contains 10% hydrogen sulfide gas;
  • the engine speed was 2000r/min
  • the in-cylinder temperature was controlled within the range of 1000-1200°C
  • the equivalence ratio was controlled within the range of 1.1-1.2.
  • control process of the equivalence ratio is as follows: the electronic control unit obtains the oxygen content in the exhaust gas and the throttle valve opening, controls the throttle valve, the fuel injector and the jet valve, and then changes the equivalence ratio.
  • the opening degree of the throttle valve is 10%-15%.
  • the control process of the temperature in the cylinder is as follows: the electronic control unit obtains the exhaust gas temperature and the internal pressure of the cylinder, estimates the temperature inside the cylinder, and controls the exhaust gas entering the cylinder or the ignition advance time or injection time of the spark plug through the EGR valve.
  • the fuel tank and the injection valve control the ratio of the intake air amount to the gasoline injection amount or the opening degree of the throttle valve or the opening degree of the EGR valve, and adjust the temperature in the cylinder.
  • the natural gas is injected into the cylinder after being mixed with fresh air by inlet port injection, and the gasoline after being mixed with the catalyst oil-soluble iron oxide nanoparticles in advance is injected into the cylinder by direct injection in the cylinder.
  • the combustible mixture is ignited by spark ignition.
  • the carbon nanotubes catalyzed by the oil-soluble iron oxide nanoparticles are reduced to obtain the carbon nanotubes catalyzed by the nano-iron particles and are discharged from the cylinder together with the exhaust gas.
  • the nanotube trap realizes the collection of carbon nanotubes and the recovery of some nano-iron particles that do not participate in the catalytic reaction; during this process, the electronic control unit controls the engine throttle valve, fuel injector, jet valve, spark plug and EGR valve. The control is carried out so that the temperature, equivalence ratio and reaction time in the engine cylinder meet the optimum conditions for the growth of carbon nanotubes, and finally the continuous mass production of carbon nanotubes with higher purity is realized.
  • the invention can not only realize the high-purity, low-pollution and continuous mass production of carbon nanotubes, but also play the role of environmental protection and energy saving.
  • the present invention utilizes the dual-fuel engine as the burner, so that the reaction environment is changed from the original atmospheric environment into the engine cylinder, so that the incompletely reacted CO, HC and other toxic substances can be effectively treated and will not be scattered into the air
  • the resulting carbon nanotube particles will also be collected in a closed environment, and will not be inhaled by the human body and endanger human health.
  • the carbon nanotubes prepared by the present invention are collected by the filter in the carbon nanotube trap after passing through the carbon nanotube trap.
  • the generated nano-iron particles that do not participate in the catalytic reaction are also adsorbed on the electromagnet coils in the carbon nanotube trap.
  • the filter and the electromagnet coil can be disassembled, put it into the particulate matter extraction device, and backflushed by dry high-pressure air to realize the recovery of carbon nanotubes and nano-iron particles.
  • FIG. 1 is a schematic structural diagram of a carbon nanotube preparation device using an ignition-type dual-fuel engine according to the present invention
  • FIG. 2 is a schematic diagram of an electronic control system in the working process of preparing carbon nanotubes according to the present invention
  • Figure 3 (a) is a schematic diagram of the internal structure of the carbon nanotube trap according to the present invention.
  • Figure 3(b) is a side view of the electromagnet end of the carbon nanotube trap according to the present invention.
  • Figure 3(c) is a side view of the filter end of the carbon nanotube trap according to the present invention.
  • FIG. 4 is a schematic structural diagram of the particulate matter extraction device according to the present invention.
  • Natural gas storage cylinder 2. Natural gas filter, 3. Pressure regulator, 4. Jet valve, 5. Throttle valve, 6. Gasoline tank, 7. Gasoline filter, 8. Fuel pump, 9. Intercooler, 10. Air filter, 11. Compressor, 12. Exhaust gas turbine, 13. Exhaust gas analyzer, 14. Three-way catalytic converter, 15. EGR valve, 16. Carbon nanotube trap , 17. Sensor signal, 18. Electronic control unit, 19. Cylinder pressure sensor, 20. Fuel injector, 21. Cylinder, 22. Spark plug, 23. Electromagnet, 24. Electromagnet coil, 25. Ceramic hole plug, 26 . filter, 27. filter membrane, 28. carbon nanotube collection chamber, 29. dry compressed air.
  • the reason why the present invention selects a dual-fuel engine to prepare carbon nanotubes is: firstly, the growth conditions of carbon nanotubes are considered.
  • the main factors affecting the formation of carbon nanotubes are temperature, carbon source and catalyst, and the secondary factors are equivalence ratio and sampling time.
  • a protective gas such as nitrogen, argon, etc. is also required.
  • controlling the temperature at 600-1200 °C is beneficial to the formation of carbon nanotubes.
  • the temperature in the range of 600-900 °C is conducive to the formation of multi-walled carbon nanotubes.
  • the temperature in the range of 900-1200 °C is conducive to the formation of single-walled carbon nanotubes
  • small molecular hydrocarbon fuels such as methane, ethylene, and acetylene
  • macromolecular heavy hydrocarbons such as benzene, toluene, and xylene can be used as carbon sources for carbon nanotube growth.
  • catalysts needed such as iron, cobalt, nickel, and their metal salts and metal oxides
  • sulfur is generally used, and hydrogen sulfide can be used as the accelerator; for the equivalent ratio, it is generally controlled at 1.1-1.2, It is beneficial to the mass generation of carbon nanotubes and ensures that the generated carbon nanotubes are not oxidized; the sampling time is selected according to the actual situation, and the optimal sampling time can collect the most carbon nanotubes.
  • the fuels of traditional engines are generally diesel and gasoline. The decomposition of diesel and gasoline can produce various alkanes, olefins and benzenes, which can meet the carbon source conditions.
  • the internal temperature of the engine cylinder can fully meet the temperature conditions for carbon nanotube growth, and it can meet Under the temperature conditions of carbon nanotube generation, a large amount of nitrogen contained in the cylinder will not be oxidized basically, and can be used as a protective gas generated by carbon nanotubes; the catalyst is ground into tiny particles and mixed into the fuel, and the catalyst can be injected into the cylinder together with the fuel. , catalyze the generation of carbon nanotubes; the engine can flexibly control the equivalence ratio and rotational speed of the fuel to meet the equivalence ratio and sampling time requirements for the production of large quantities of carbon nanotubes.
  • carbon nanotubes will be continuously generated in the engine cylinder, and the carbon nanotubes will be discharged with the exhaust gas and will be collected after passing through the carbon nanotube collection device. It can be used as a device for continuous production of carbon nanotubes in batches.
  • the engine will inevitably generate soot, and related studies have shown that the generation of soot will inhibit the generation of carbon nanotubes. In order to suppress the formation of soot without changing the growth conditions of carbon nanotubes, it is necessary to use a dual-fuel engine.
  • Injecting fuels such as alcohol and natural gas in the intake port is beneficial to improve the combustion conditions in the engine cylinder and reduce the generation of soot.
  • the generation of carbon nanotubes increases; at the same time, the dual-fuel engine with port injection and in-cylinder direct injection is used, and the adjustment of carbon nanotube generation conditions is more flexible, which is more conducive to the mass production of carbon nanotubes.
  • the fuel is burned in free space, so the use of some gas fuels has potential safety hazards. For example, the generated carbon nanotubes will be inhaled by the human body, which will reduce cell viability, even lead to lung cancer, and also cause environmental pollution.
  • the fuel is burned inside the cylinder, which enhances the safety factor, and the combustion exhaust gas is post-treated to reduce environmental pollution, and at the same time generate carbon.
  • the external power output of the engine crankshaft can be used to generate electricity and thus increase the fuel utilization rate.
  • a carbon nanotube preparation device using an ignition type dual-fuel engine shown in FIG. 1 includes a natural gas storage cylinder 1, a natural gas filter 2, a pressure regulator 3, a gasoline tank 6, a gasoline filter 7, and a fuel pump 8 , intercooler 9 , air cleaner 10 , compressor 11 , exhaust gas turbine 12 , three-way catalytic converter 14 , carbon nanotube trap 16 , electronic control unit 18 , fuel injector 20 and cylinder 21 .
  • the natural gas storage bottle 1 and the natural gas filter 2 are connected through a pipeline, and a pressure reducing valve is arranged on the connecting pipeline. Connected, and the connection between the pressure regulator 3 and the intake port is provided with a jet valve 4; the intake port of the cylinder 21 is sequentially provided with an air filter 10, a compressor 11, an intercooler 9 and a throttle valve 5 along the intake direction.
  • the exhaust pipe of cylinder 21 is sequentially provided with carbon nanotube trap 16, EGR valve 15, exhaust gas turbine 12, exhaust gas analyzer 13 and three-way catalytic converter 14 along the exhaust direction;
  • the EGR valve 15 is provided, which is communicated with the intake port through a pipeline;
  • the compressor 11 is connected with the exhaust gas turbine 12 through a coupling;
  • the cylinder 21 is provided with a fuel injector 20, and the fuel injector 20 is sequentially connected with the fuel pump 8 and gasoline through the pipeline.
  • the filter 7 is communicated with the gasoline tank 6, and a shut-off valve is provided between the gasoline tank 6 and the gasoline filter 7; the spark plug 22 on the top of the cylinder 21, the cylinder pressure sensor 19 are signally connected to the electronic control unit (ECU) 18, and the electronic
  • the control unit 18 is also signally connected with the jet valve 4, the throttle valve 5, and the EGR valve 15, and the electronic control unit 18 receives the sensor signal 17 and controls the throttle valve 5, the jet valve 4, the fuel injector 20, the spark plug 22 and the EGR valve 15, so that The environment in the engine cylinder meets the growth conditions of carbon nanotubes, so as to generate as many carbon nanotubes as possible.
  • the exhaust gas analyzer 13 sends the detected CO concentration to the electronic control unit 18 .
  • the sensor signal 17 includes the oxygen content in the exhaust gas, the exhaust gas temperature, the throttle valve opening, the engine speed, the exhaust back pressure and the pressure in the engine cylinder.
  • the oxygen content in the exhaust gas is obtained by the oxygen sensor.
  • the exhaust temperature is obtained by the temperature sensor
  • the throttle opening is obtained by the throttle position sensor
  • the engine speed is obtained by the speed sensor
  • the exhaust back pressure is obtained by the back pressure sensor
  • the pressure in the engine cylinder is obtained by the cylinder pressure sensor 19
  • the sensor, temperature sensor and back pressure sensor are installed in the exhaust port before the carbon nanotube trap 16, the throttle valve position sensor is installed at the throttle valve 5, and the speed sensor is installed at the engine gear shaft;
  • the exhaust gas turbine 12 and the three-way catalysis A back pressure sensor is also installed on the pipe between the converters 14 .
  • the carbon nanotube trap 16 has a cylindrical shape as a whole, and a plurality of electromagnets 23 and filters 26 are respectively arranged at both ends of the carbon nanotube trap 16 ;
  • the electromagnet 23 is cylindrical, and the electromagnet
  • the electromagnet coil 24 is wound on the 23, and the electromagnet coils 24 provided on the adjacent electromagnets 23 are different, that is, one electromagnet 23 is wound with the electromagnet coil 24 at both ends, and the other electromagnet 23 is wound at the middle position.
  • the iron coil 24 is shown in FIG.
  • the filter 26 is cylindrical, a plurality of cuboid-shaped ceramic hole plugs 25 are arranged inside the filter 26, and the adjacent ceramic hole plugs 25 arranged inside the filter 26 are not The same, that is, a ceramic hole plug 25 is arranged at one end of the filter 26, and a ceramic hole plug 25 is arranged at another middle position of the filter 26, as shown in FIG. 3(c).
  • the exhaust gas in the cylinder 21 first passes through the electromagnet 23, and the nano-iron particles in the exhaust gas have magnetism and will be adsorbed on the magnetic side of the electromagnet coil 24;
  • the diameter is 1-2nm, the length is 5-100um, and has a large aspect ratio.
  • the pore size of the ceramic hole plug 25 and the filter 26 are both 1um, which are used to filter out carbon nanotubes; when the exhaust gas is trapped by carbon nanotubes When the device 16 is turned on, the carbon nanotubes in the exhaust gas are trapped, and the nano-iron particles that do not participate in the reaction will also be adsorbed on the electromagnet 23 to play the role of recycling.
  • the filter 26 is a device for extracting particulate matter, which is used to place the filter 26 in the carbon nanotube collection chamber 28.
  • One end of the carbon nanotube collection chamber 28 is fed with dry compressed air 29, and the other end is provided with a filter membrane 27.
  • the flow direction of the dry compressed air 29 is opposite to the gas flow direction when the carbon nanotube trap 16 captures particulate matter
  • the carbon nanotubes are blown into the carbon nanotube collection cavity 28, and the filter membrane 27 only allows air to pass through.
  • the carbon nanotube particles are extracted from the carbon nanotube collection cavity 28 ; at the same time, the nano iron particles are blown out by the dry compressed air 29 according to this principle.
  • the present invention adopts the working principle of the carbon nanotube preparation device of the ignition type dual-fuel engine as follows:
  • the electronic control unit 18 controls the jet valve 4 to open, and the natural gas in the natural gas storage cylinder 1 enters the intake port of the engine through the natural gas filter 2, and is mixed with fresh air and injected into the cylinder 21; open the gasoline tank 6 and the gasoline filter
  • the shut-off valve between 7, the gasoline mixed with the catalyst and the accelerator in advance, after ultrasonic treatment in an ultrasonic water bath, after mixing evenly, is injected into the cylinder 21 through the gasoline filter 7, the fuel pump 8 and the fuel injector 20 in turn. After the two fuels enter the cylinder 21, the combustible gas mixture is ignited by spark ignition or compression ignition.
  • the generated carbon nanotubes are discharged from the cylinder 21 together with the exhaust gas, and the exhaust gas passes through the carbon nanotubes.
  • the trap 16 carbon nanotubes and a small amount of unburned particulate matter will be filtered, and the exhaust gas will pass through the ERG valve 15, and part of the exhaust gas will re-enter the cylinder 21 to control the temperature in the cylinder and inhibit the generation of NOx.
  • the electronic control unit 18 receives the signals of the oxygen sensor and the throttle valve position sensor to control the throttle valve 5, the fuel injector 20 and the injection valve 4, thereby changing the fuel equivalent in the cylinder Control the equivalence ratio within the range of 1.1-1.2.
  • the equivalence ratio is less than 1.1, reduce the throttle opening and increase the injector valve opening and the jet valve opening; if the equivalence ratio is greater than 1.2, increase The opening of the throttle valve reduces the opening of the injector valve and the opening of the jet valve; the opening of the throttle valve (0-50%) changes the equivalence ratio and affects the CO concentration, the larger the throttle opening, the smaller the equivalence ratio, 10
  • the throttle opening of %-15% makes the equivalence ratio in the range of 1.1-1.2, and the CO concentration can be guaranteed to be higher than 10%; the electronic control unit 18 receives the signals from the temperature sensor and the cylinder pressure sensor 19, according to the cylinder internal pressure and exhaust gas.
  • the temperature estimates the temperature inside the cylinder 21, and controls the exhaust gas entering the cylinder 21 through the EGR valve 15 or the ignition advance time of the spark plug 22 or the fuel injector 20 and the jet valve 4 to control the consumption of natural gas and gasoline or the throttle opening. Or the opening of the EGR valve 15, the in-cylinder temperature can be adjusted to maintain it within the range of 1000-1200°C.
  • the ratio of the natural gas intake amount to the gasoline injection amount is increased or increased Ignition advance angle or increase the throttle valve opening or reduce the EGR rate (reduce the opening of the EGR valve 15, reduce the exhaust gas entering the cylinder 21), if the temperature is higher than 1200 °C, reduce the amount of natural gas intake and gasoline
  • the ratio of the injection amount or reduce the ignition advance angle or reduce the throttle valve opening or increase the EGR rate (increase the opening of the EGR valve 15, increase the exhaust gas entering the cylinder 21); the electronic control unit 18 receives the signal from the speed sensor, Control the jet valve 4, the fuel injector 20 and the spark plug 22, change the fuel injection volume, the injection volume and the ignition time, and then adjust the engine speed.
  • the response time is regulated; the electronic control unit 18 receives the signal of the back pressure sensor, when the carbon nanotube trap 16 is blocked due to the excessive amount of particulate matter, and the exhaust back pressure is too large, the electronic control unit 18 controls the fuel injector 20 and the jet valve 4 stop the fuel supply and end the engine operation to avoid damage to the engine and the sensor. Therefore, by using the electronic control unit 18 to control the engine, it is possible to generate as many carbon nanotubes as possible in the engine cylinder under normal operating conditions.
  • the electronic control unit 18 can also control the injection pressure, EGR rate and ignition timing to suppress the generation of soot in the cylinder and ensure the purity of carbon nanotubes by controlling the synchronization of fuel injection timing and in-cylinder intake timing.
  • the natural gas selected in this example is high-sulfur natural gas with a sulfur content higher than 4%, and the gasoline is National V standard gasoline with a sulfur content ⁇ 10ppm.
  • the cylinder pressure sensor 19 collects the signal to analyze the cylinder The internal pressure, and then the average temperature in the engine cylinder is predicted, and it is determined that the temperature range is 600-1200 ° C, and the CO concentration is guaranteed to be higher than 10%.
  • the electronic control unit 18 is used to feedback the operating conditions of the engine Control, so that the engine has been maintained in the best conditions for carbon nanotube generation.
  • the generated carbon nanotubes are discharged from the cylinder 21 together with the exhaust gas.
  • the carbon nanotubes will be trapped, and at the same time, the carbon nanotubes will be trapped during the generation of carbon nanotubes.
  • iron oxide is reduced to iron to catalyze the formation of carbon nanotubes, and a part of iron that does not participate in the reaction forms iron particles that will be adsorbed by the electromagnet 23 as the exhaust gas is discharged from the cylinder to play the role of recycling.
  • Both the electromagnet 23 and the filter 26 can be disassembled, respectively put them into the particle extraction device, and after the backflushing of the dry high-pressure air 29, the iron particles and carbon nanotubes are removed from the electromagnet coil 24 and the filter 26 respectively. Blow out into the collection chamber 28 to realize the collection of the two.

Abstract

A carbon nanotube preparation device using a spark-ignition dual-fuel engine, the device comprising a natural gas storage cylinder (1), a gasoline tank (6) and a dual-fuel engine, wherein natural gas is ejected by using a gas intake passage and mixed with fresh air, and is then injected into an air cylinder (21); gasoline pre-mixed with catalyst oil-soluble ferric oxide nanoparticles is injected into the air cylinder (21) in a direct injection manner; after the two fuels enter the air cylinder (21), a combustible gas mixture is ignited in a spark ignition manner; and after a reaction in the air cylinder, a generated carbon nanotube is discharged out of the air cylinder (21) together with waste gas, and the waste gas passes through a carbon nanotube catcher (16) to collect the carbon nanotube and recover some iron nanoparticles, which are generated by means of reduction and have not participated in a catalytic reaction. The device further comprises an ECU, which is used for controlling an engine throttle valve (5), a gasoline injector (20), a gas injection valve (4), a spark plug (22) and an EGR valve (15), such that the internal temperature of the air cylinder (21) of the engine, the equivalence ratio and the reaction time can meet the optimal conditions for the growth of a carbon nanotube, thereby realizing continuous mass production of high-purity carbon nanotubes. Further provided is a carbon nanotube preparation method using a spark-ignition dual-fuel engine.

Description

一种采用点燃式双燃料发动机的碳纳米管制备装置及方法A kind of carbon nanotube preparation device and method using ignition type dual fuel engine 技术领域technical field
本发明属于材料制备技术领域，具体涉及一种采用点燃式双燃料发动机的碳纳米管制备装置及方法。The invention belongs to the technical field of material preparation, and in particular relates to a carbon nanotube preparation device and method using an ignition type dual-fuel engine.
背景技术Background technique
目前，碳纳米管因具有良好的导电性能、力学性能、热学性能、超导性能、储氢性能及光学性能被广泛的应用于高强度材料、传感器、纳米电子学、能量储存、催化剂载体、生物医学等领域，具有十分广阔的应用前景。从1991年碳纳米管被发现到现在，国内外学者已经对碳纳米管做了大量的研究，在其制备与应用方面取得了丰富的成果。对于碳纳米管的制备，目前已经相当成熟的方法有：电弧放电法、化学气相沉积法、激光蒸发法及火焰法，前三种方法都需要额外的供给能量，使得能耗增大，成本变高，为了解决这一问题火焰法应运而生。火焰法是近二十年逐渐发展起来的碳纳米管新型制备方法，其充分的利用了碳氢燃烧所产生的碳源和热源去制备碳纳米管，无需额外提供能量，具有低能耗、低成本、高效能等优点，因此受到了众多学者的关注，然而火焰法同时也存在着杂质多，涉及危险气体及产生有害污染气体等缺点，所以其具有很大的改良与优化空间。At present, carbon nanotubes are widely used in high-strength materials, sensors, nanoelectronics, energy storage, catalyst supports, biological It has a very broad application prospect in medicine and other fields. From the discovery of carbon nanotubes in 1991 to the present, scholars at home and abroad have done a lot of research on carbon nanotubes, and have achieved rich results in their preparation and application. For the preparation of carbon nanotubes, there are quite mature methods: arc discharge method, chemical vapor deposition method, laser evaporation method and flame method. The first three methods all require additional energy supply, which increases energy consumption and costs. Gao, in order to solve this problem, the flame method came into being. The flame method is a new preparation method of carbon nanotubes that has been gradually developed in the past two decades. It makes full use of the carbon source and heat source generated by the combustion of hydrocarbons to prepare carbon nanotubes without additional energy, and has low energy consumption and low cost. However, the flame method also has shortcomings such as many impurities, involving dangerous gases and producing harmful polluting gases, so it has a lot of room for improvement and optimization.
发明内容SUMMARY OF THE INVENTION
针对现有技术中存在不足，本发明提供了一种采用点燃式双燃料发动机的碳纳米管制备装置及方法，实现碳纳米管高纯度、低污染、连续大批量的生产。In view of the deficiencies in the prior art, the present invention provides a carbon nanotube preparation device and method using an ignition type dual-fuel engine, so as to realize the high-purity, low-pollution, continuous mass production of carbon nanotubes.
本发明是通过以下技术手段实现上述技术目的的。The present invention achieves the above technical purpose through the following technical means.
一种采用点燃式双燃料发动机的碳纳米管制备装置，包括天然气贮气瓶和汽油箱；A carbon nanotube preparation device using an ignition type dual-fuel engine, comprising a natural gas storage cylinder and a gasoline tank;
所述天然气贮气瓶通过管道与气缸的进气道连通，且天然气贮气瓶与进气道连接处设有喷气阀门；气缸的进气道上设有节气门；气缸的排气管上沿排气方向依次设有碳纳米管捕集器、EGR阀和尾气分析仪，且排气管在设置EGR阀处，通过管道与进气道连通；The natural gas storage cylinder is communicated with the air inlet of the cylinder through a pipeline, and a jet valve is provided at the connection between the natural gas storage cylinder and the air inlet; a throttle valve is arranged on the air inlet of the cylinder; A carbon nanotube trap, an EGR valve and an exhaust gas analyzer are arranged in sequence in the gas direction, and the exhaust pipe is connected to the intake port through a pipeline where the EGR valve is set;
所述汽油箱通过管道与设置在气缸上的喷油器连通，且汽油箱的管道上设有截止阀；The gasoline tank is communicated with a fuel injector arranged on the cylinder through a pipeline, and a stop valve is provided on the pipeline of the gasoline tank;
所述气缸顶部设有火花塞和缸压传感器；The top of the cylinder is provided with a spark plug and a cylinder pressure sensor;
所述喷气阀门、节气门、尾气分析仪、EGR阀、火花塞、缸压传感器均与电子控制单元信号连接，电子控制单元还接收的信号包括：排气中的氧含量、排气温度、节气门开度、发动机的转速、排气背压和发动机缸内压力。The jet valve, throttle valve, exhaust gas analyzer, EGR valve, spark plug, and cylinder pressure sensor are all signal-connected to the electronic control unit, and the signals also received by the electronic control unit include: oxygen content in the exhaust, exhaust temperature, throttle valve opening, engine speed, exhaust back pressure and engine in-cylinder pressure.
上述技术方案中，所述碳纳米管捕集器两端分别设置若干电磁铁和过滤器，电磁铁上缠 绕有电磁铁线圈，且相邻电磁铁上设置的电磁铁线圈均不相同；过滤器内部设有若干长方体状的陶瓷孔塞，且过滤器内部设置的相邻陶瓷孔塞均不相同。In the above technical solution, several electromagnets and filters are respectively arranged at both ends of the carbon nanotube trap, and electromagnet coils are wound around the electromagnets, and the electromagnet coils arranged on adjacent electromagnets are different; Several cuboid-shaped ceramic hole plugs are arranged inside, and the adjacent ceramic hole plugs arranged inside the filter are different.
上述技术方案中，所述气缸的排气管上还设有废气涡轮和三效催化转化器，废气涡轮位于尾气分析仪和EGR阀之间，所述尾气分析仪位于废气涡轮和三效催化转化器之间。In the above technical solution, an exhaust gas turbine and a three-way catalytic converter are also provided on the exhaust pipe of the cylinder, and the exhaust gas turbine is located between the exhaust gas analyzer and the EGR valve, and the exhaust gas analyzer is located between the exhaust gas turbine and the three-way catalytic converter. between the devices.
上述技术方案中，所述气缸的进气道上沿进气方向还依次设有空气滤清器、压气机和中冷器，且压气机与废气涡轮连接。In the above technical solution, an air filter, a compressor and an intercooler are arranged on the intake passage of the cylinder in sequence along the intake direction, and the compressor is connected with the exhaust gas turbine.
上述技术方案中，所述喷油器与汽油箱之间沿进油方向还依次设有汽油滤清器和燃油泵。In the above technical solution, a gasoline filter and a fuel pump are also arranged in sequence between the fuel injector and the fuel tank along the fuel inlet direction.
上述技术方案中，所述天然气贮气瓶与喷气阀门之间沿进气方向还依次设有天然气滤清器和压力调节器。In the above technical solution, a natural gas filter and a pressure regulator are arranged in sequence along the air intake direction between the natural gas storage cylinder and the jet valve.
一种采用点燃式双燃料发动机的碳纳米管制备方法，具体为：A method for preparing carbon nanotubes using an ignition type dual-fuel engine, specifically:
天然气和新鲜空气混合后注入气缸内，与催化剂混合好的汽油也喷入气缸内，经过缸内反应后，废气通过碳纳米管捕集器后，部分废气通过ERG阀重新进入气缸，剩余的大部分废气通过废气涡轮和三元催化转换器后，排入大气；The natural gas and fresh air are mixed and injected into the cylinder, and the gasoline mixed with the catalyst is also injected into the cylinder. After the reaction in the cylinder, after the exhaust gas passes through the carbon nanotube trap, part of the exhaust gas re-enters the cylinder through the ERG valve, and the rest is large. Part of the exhaust gas is discharged into the atmosphere after passing through the exhaust gas turbine and the three-way catalytic converter;
所述天然气与汽油的消耗量比值为0.4-0.5，所述催化剂为7000ppm的油溶性氧化铁纳米颗粒，所述天然气中含有10％的硫化氢气体；The consumption ratio of the natural gas to gasoline is 0.4-0.5, the catalyst is 7000ppm oil-soluble iron oxide nanoparticles, and the natural gas contains 10% hydrogen sulfide gas;
缸内反应过程中，发动机转速为2000r/min，缸内温度控制在1000-1200℃范围内，当量比控制在1.1-1.2范围内。During the in-cylinder reaction process, the engine speed was 2000r/min, the in-cylinder temperature was controlled within the range of 1000-1200°C, and the equivalence ratio was controlled within the range of 1.1-1.2.
进一步，所述当量比的控制过程为：电子控制单元获取排气中的氧含量和节气门开度，对节气门、喷油器和喷气阀门进行控制，进而改变当量比。Further, the control process of the equivalence ratio is as follows: the electronic control unit obtains the oxygen content in the exhaust gas and the throttle valve opening, controls the throttle valve, the fuel injector and the jet valve, and then changes the equivalence ratio.
更进一步，所述节气门的开度为10％-15％。Further, the opening degree of the throttle valve is 10%-15%.
进一步，所述缸内温度的控制过程为：电子控制单元获取排气温度和气缸内部压力，对气缸内部的温度进行预估，通过EGR阀控制进入气缸内部的废气或者火花塞的点火提前时间或者喷油器和喷气阀门控制进气量与汽油喷射量的比值或者节气门开度或者EGR阀的开度，对缸内温度进行调节。Further, the control process of the temperature in the cylinder is as follows: the electronic control unit obtains the exhaust gas temperature and the internal pressure of the cylinder, estimates the temperature inside the cylinder, and controls the exhaust gas entering the cylinder or the ignition advance time or injection time of the spark plug through the EGR valve. The fuel tank and the injection valve control the ratio of the intake air amount to the gasoline injection amount or the opening degree of the throttle valve or the opening degree of the EGR valve, and adjust the temperature in the cylinder.
本发明的有益效果为：The beneficial effects of the present invention are:
(1)本发明中，天然气采用进气道喷射与新鲜空气混合后注入气缸内，提前与催化剂油溶性氧化铁纳米颗粒混合好后的汽油采用缸内直喷的方式喷入气缸，两种燃料进入气缸后采用火花式点火方式点燃可燃混合气，经过缸内复杂的化学反应，由油溶性氧化铁纳米颗粒还原得到纳米铁颗粒所催化生成的碳纳米管随废气一起被排出气缸，废气通过碳纳米管捕集器，实现碳纳米管的收集及部分未参与催化反应的纳米铁颗粒的回收；在此工作过程中，电子控制单元对发动机节气门、喷油器、喷气阀门、火花塞及EGR阀进行控制，使得发动机缸内的温度、当量比、反应时间满足碳纳米管生长的最佳条件，最终实现较高纯度碳纳米管的连续 大批量生产。本发明不仅可以实现碳纳米管高纯度、低污染、连续大批量的生产，还能起到环保节能的作用。(1) In the present invention, the natural gas is injected into the cylinder after being mixed with fresh air by inlet port injection, and the gasoline after being mixed with the catalyst oil-soluble iron oxide nanoparticles in advance is injected into the cylinder by direct injection in the cylinder. After entering the cylinder, the combustible mixture is ignited by spark ignition. After the complex chemical reaction in the cylinder, the carbon nanotubes catalyzed by the oil-soluble iron oxide nanoparticles are reduced to obtain the carbon nanotubes catalyzed by the nano-iron particles and are discharged from the cylinder together with the exhaust gas. The nanotube trap realizes the collection of carbon nanotubes and the recovery of some nano-iron particles that do not participate in the catalytic reaction; during this process, the electronic control unit controls the engine throttle valve, fuel injector, jet valve, spark plug and EGR valve. The control is carried out so that the temperature, equivalence ratio and reaction time in the engine cylinder meet the optimum conditions for the growth of carbon nanotubes, and finally the continuous mass production of carbon nanotubes with higher purity is realized. The invention can not only realize the high-purity, low-pollution and continuous mass production of carbon nanotubes, but also play the role of environmental protection and energy saving.
(2)本发明利用双燃料发动机作为燃烧器，使反应环境由原来的大气环境下变为在发动机气缸内，这样使得未完全反应的CO、HC等有毒物质能够被有效处理不会散入空气中造成环境污染，生成的碳纳米管颗粒也会在密闭环境下被收集，不会被人体吸入危害人体健康。(2) The present invention utilizes the dual-fuel engine as the burner, so that the reaction environment is changed from the original atmospheric environment into the engine cylinder, so that the incompletely reacted CO, HC and other toxic substances can be effectively treated and will not be scattered into the air The resulting carbon nanotube particles will also be collected in a closed environment, and will not be inhaled by the human body and endanger human health.
(3)本发明制备的碳纳米管经过碳纳米管捕集器后被其中的过滤器收集，此外生成的未参与催化反应的纳米铁颗粒也吸附碳纳米管捕集器中的电磁铁线圈上；过滤器与电磁铁线圈均可拆卸，将其放入颗粒物提取装置中，经过干燥高压空气进行反吹，实现碳纳米管及纳米铁颗粒的回收。(3) The carbon nanotubes prepared by the present invention are collected by the filter in the carbon nanotube trap after passing through the carbon nanotube trap. In addition, the generated nano-iron particles that do not participate in the catalytic reaction are also adsorbed on the electromagnet coils in the carbon nanotube trap. ; The filter and the electromagnet coil can be disassembled, put it into the particulate matter extraction device, and backflushed by dry high-pressure air to realize the recovery of carbon nanotubes and nano-iron particles.
附图说明Description of drawings
图1为本发明所述采用点燃式双燃料发动机的碳纳米管制备装置的结构示意图；1 is a schematic structural diagram of a carbon nanotube preparation device using an ignition-type dual-fuel engine according to the present invention;
图2为本发明制备碳纳米管工作过程中的电子控制***示意图；2 is a schematic diagram of an electronic control system in the working process of preparing carbon nanotubes according to the present invention;
图3(a)为本发明所述碳纳米管捕集器的内部结构示意图；Figure 3 (a) is a schematic diagram of the internal structure of the carbon nanotube trap according to the present invention;
图3(b)为本发明所述碳纳米管捕集器电磁铁端侧视图；Figure 3(b) is a side view of the electromagnet end of the carbon nanotube trap according to the present invention;
图3(c)为本发明所述碳纳米管捕集器过滤器端侧视图；Figure 3(c) is a side view of the filter end of the carbon nanotube trap according to the present invention;
图4为本发明所述颗粒物提取装置的结构示意图；4 is a schematic structural diagram of the particulate matter extraction device according to the present invention;
图中：1.天然气贮气瓶，2.天然气滤清器，3.压力调节器，4.喷气阀门，5.节气门，6.汽油箱，7.汽油滤清器，8.燃油泵，9.中冷器，10.空气滤清器，11.压气机，12.废气涡轮，13.尾气分析仪，14.三效催化转化器，15.EGR阀，16.碳纳米管捕集器，17.传感器信号，18.电子控制单元，19.缸压传感器，20.喷油器，21.气缸，22.火花塞，23.电磁铁，24.电磁铁线圈，25.陶瓷孔塞，26.过滤器，27.过滤膜，28.碳纳米管收集腔，29.干燥压缩空气。In the picture: 1. Natural gas storage cylinder, 2. Natural gas filter, 3. Pressure regulator, 4. Jet valve, 5. Throttle valve, 6. Gasoline tank, 7. Gasoline filter, 8. Fuel pump, 9. Intercooler, 10. Air filter, 11. Compressor, 12. Exhaust gas turbine, 13. Exhaust gas analyzer, 14. Three-way catalytic converter, 15. EGR valve, 16. Carbon nanotube trap , 17. Sensor signal, 18. Electronic control unit, 19. Cylinder pressure sensor, 20. Fuel injector, 21. Cylinder, 22. Spark plug, 23. Electromagnet, 24. Electromagnet coil, 25. Ceramic hole plug, 26 . filter, 27. filter membrane, 28. carbon nanotube collection chamber, 29. dry compressed air.
具体实施方式Detailed ways
下面结合附图以及具体实施例对本发明作进一步的说明，但本发明的保护范围并不限于此。The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.
本发明选择双燃料发动机制备碳纳米管的原因是：首先考虑碳纳米管的生长条件，碳纳米管生成的主要影响因素为温度、碳源与催化剂，次要因素为当量比与采样时间，此外还需要保护气体如氮气、氩气等。对于温度，控制在600-1200℃有利于碳纳米管的生成，一般温度在600-900℃范围有利于多壁碳纳米管的生成，温度在900-1200℃范围有利于单壁碳纳米管的生成；对于碳源，大量研究表明甲烷、乙烯、乙炔等小分子碳氢燃料及大分子重烃如苯、甲苯、二甲苯等都能够作为碳纳米管生长的碳源；对于碳纳米管生长所需的催化剂则种类繁 多，例如铁、钴、镍，及其金属盐和金属氧化物等；对于促进剂一般选用硫，可以选用硫化氢作为促进剂；对于当量比，一般控制在1.1-1.2，有利于碳纳米管的大量生成并且保证生成的碳纳米管不被氧化；对于采样时间则根据实际情况选取，最佳采样时间能搜集到最多的碳纳米管。传统发动机的燃料一般为柴油和汽油，柴油和汽油的分解能产生各种烷烃、烯烃及苯类物质，可以满足碳源条件，发动机的气缸内部温度完全可以满足碳纳米管生长的温度条件，而且满足碳纳米管生成的温度条件时，缸内含有的大量氮气基本不会被氧化，能作为碳纳米管生成的保护气体；将催化剂研磨成微小颗粒物混入燃料，催化剂可随着燃料一起喷入到气缸中，催化碳纳米管的生成；发动机可以灵活地控制燃料的当量比和转速，去满足大批量碳纳米管生成的当量比和采样时间需求。由此可见，在满足这些要求后，随着发动机的正常运行，发动机缸内将源源不断地生成碳纳米管，碳纳米管随着废气排出，经过碳纳米管搜集装置后被捕集，因此发动机可作为批量连续生产碳纳米管的装置。然而，在满足碳纳米管生成的条件下，发动机将不可避免的生成碳烟，相关研究表明碳烟的生成会抑制碳纳米管的生成。为了抑制碳烟的生成且不改变碳纳米管的生长条件，因而需要使用一种双燃料发动机，在进气道喷射醇类及天然气等燃料有利于改善发动机缸内燃烧状况，使得碳烟生成减少，碳纳米管生成增多；同时采用进气道喷射和缸内直喷式双燃料发动机，对碳纳米管生成工况的调节更加灵活，更加利于碳纳米管的批量生产。其次传统燃烧器制备碳纳米管时，燃料在自由空间下燃烧，这样使用一些气体燃料存在安全隐患，例如生成的碳纳米管被人体吸入会降低细胞生存能力，甚至导致肺癌，此外还造成环境污染以及燃烧过程中许多能量散发到空气中造成能源浪费，而本发明在制备碳纳米管的过程中燃料在气缸内部燃烧，增强了安全系数，燃烧废气经过后处理减少了环境污染，同时在生成碳纳米管的过程中，发动机曲轴对外输出功可以用于发电进而增加燃料利用率。The reason why the present invention selects a dual-fuel engine to prepare carbon nanotubes is: firstly, the growth conditions of carbon nanotubes are considered. The main factors affecting the formation of carbon nanotubes are temperature, carbon source and catalyst, and the secondary factors are equivalence ratio and sampling time. In addition, A protective gas such as nitrogen, argon, etc. is also required. As for the temperature, controlling the temperature at 600-1200 °C is beneficial to the formation of carbon nanotubes. Generally, the temperature in the range of 600-900 °C is conducive to the formation of multi-walled carbon nanotubes. The temperature in the range of 900-1200 °C is conducive to the formation of single-walled carbon nanotubes For carbon sources, a large number of studies have shown that small molecular hydrocarbon fuels such as methane, ethylene, and acetylene, and macromolecular heavy hydrocarbons such as benzene, toluene, and xylene can be used as carbon sources for carbon nanotube growth. There are many kinds of catalysts needed, such as iron, cobalt, nickel, and their metal salts and metal oxides; for the accelerator, sulfur is generally used, and hydrogen sulfide can be used as the accelerator; for the equivalent ratio, it is generally controlled at 1.1-1.2, It is beneficial to the mass generation of carbon nanotubes and ensures that the generated carbon nanotubes are not oxidized; the sampling time is selected according to the actual situation, and the optimal sampling time can collect the most carbon nanotubes. The fuels of traditional engines are generally diesel and gasoline. The decomposition of diesel and gasoline can produce various alkanes, olefins and benzenes, which can meet the carbon source conditions. The internal temperature of the engine cylinder can fully meet the temperature conditions for carbon nanotube growth, and it can meet Under the temperature conditions of carbon nanotube generation, a large amount of nitrogen contained in the cylinder will not be oxidized basically, and can be used as a protective gas generated by carbon nanotubes; the catalyst is ground into tiny particles and mixed into the fuel, and the catalyst can be injected into the cylinder together with the fuel. , catalyze the generation of carbon nanotubes; the engine can flexibly control the equivalence ratio and rotational speed of the fuel to meet the equivalence ratio and sampling time requirements for the production of large quantities of carbon nanotubes. It can be seen that after meeting these requirements, with the normal operation of the engine, carbon nanotubes will be continuously generated in the engine cylinder, and the carbon nanotubes will be discharged with the exhaust gas and will be collected after passing through the carbon nanotube collection device. It can be used as a device for continuous production of carbon nanotubes in batches. However, under the condition that carbon nanotubes are generated, the engine will inevitably generate soot, and related studies have shown that the generation of soot will inhibit the generation of carbon nanotubes. In order to suppress the formation of soot without changing the growth conditions of carbon nanotubes, it is necessary to use a dual-fuel engine. Injecting fuels such as alcohol and natural gas in the intake port is beneficial to improve the combustion conditions in the engine cylinder and reduce the generation of soot. , the generation of carbon nanotubes increases; at the same time, the dual-fuel engine with port injection and in-cylinder direct injection is used, and the adjustment of carbon nanotube generation conditions is more flexible, which is more conducive to the mass production of carbon nanotubes. Secondly, when carbon nanotubes are prepared by traditional burners, the fuel is burned in free space, so the use of some gas fuels has potential safety hazards. For example, the generated carbon nanotubes will be inhaled by the human body, which will reduce cell viability, even lead to lung cancer, and also cause environmental pollution. And in the combustion process, a lot of energy is dissipated into the air, causing energy waste, while in the process of preparing carbon nanotubes, the fuel is burned inside the cylinder, which enhances the safety factor, and the combustion exhaust gas is post-treated to reduce environmental pollution, and at the same time generate carbon. In the process of nanotubes, the external power output of the engine crankshaft can be used to generate electricity and thus increase the fuel utilization rate.
图1所示一种采用点燃式双燃料发动机的碳纳米管制备装置，包括天然气贮气瓶1、天然气滤清器2、压力调节器3、汽油箱6、汽油滤清器7、燃油泵8、中冷器9、空气滤清器10、压气机11、废气涡轮12、三效催化转化器14、碳纳米管捕集器16、电子控制单元18、喷油器20和气缸21。A carbon nanotube preparation device using an ignition type dual-fuel engine shown in FIG. 1 includes a natural gas storage cylinder 1, a natural gas filter 2, a pressure regulator 3, a gasoline tank 6, a gasoline filter 7, and a fuel pump 8 , intercooler 9 , air cleaner 10 , compressor 11 , exhaust gas turbine 12 , three-way catalytic converter 14 , carbon nanotube trap 16 , electronic control unit 18 , fuel injector 20 and cylinder 21 .
天然气贮气瓶1和天然气滤清器2通过管道连接，且连接管道上设有减压阀，天然气滤清器2与压力调节器3通过管道连接，压力调节器3与气缸21的进气道连通，且压力调节器3与进气道连接处设有喷气阀门4；气缸21的进气道上沿进气方向依次设有空气滤清器10、压气机11、中冷器9以及节气门5；气缸21的排气管上沿排气方向依次设有碳纳米管捕集器16、EGR阀15、废气涡轮12、尾气分析仪13和三效催化转化器14；气缸21的排气管在设置EGR阀15处，通过管道与进气道连通；压气机11与废气涡轮12通过联轴器连接；气缸 21上设有喷油器20，喷油器20通过管道依次与燃油泵8、汽油滤清器7和汽油箱6连通，且汽油箱6和汽油滤清器7之间设有截止阀；气缸21顶部的火花塞22、缸压传感器19与电子控制单元(ECU)18信号连接，电子控制单元18还与喷气阀门4、节气门5、EGR阀15信号连接，电子控制单元18接收传感器信号17，控制节气门5、喷气阀门4、喷油器20、火花塞22和EGR阀15，使得发动机气缸内环境满足碳纳米管的生长条件，尽可能生成更多的碳纳米管。尾气分析仪13将检测出的CO浓度发送给电子控制单元18。The natural gas storage bottle 1 and the natural gas filter 2 are connected through a pipeline, and a pressure reducing valve is arranged on the connecting pipeline. Connected, and the connection between the pressure regulator 3 and the intake port is provided with a jet valve 4; the intake port of the cylinder 21 is sequentially provided with an air filter 10, a compressor 11, an intercooler 9 and a throttle valve 5 along the intake direction. ; The exhaust pipe of cylinder 21 is sequentially provided with carbon nanotube trap 16, EGR valve 15, exhaust gas turbine 12, exhaust gas analyzer 13 and three-way catalytic converter 14 along the exhaust direction; The EGR valve 15 is provided, which is communicated with the intake port through a pipeline; the compressor 11 is connected with the exhaust gas turbine 12 through a coupling; the cylinder 21 is provided with a fuel injector 20, and the fuel injector 20 is sequentially connected with the fuel pump 8 and gasoline through the pipeline. The filter 7 is communicated with the gasoline tank 6, and a shut-off valve is provided between the gasoline tank 6 and the gasoline filter 7; the spark plug 22 on the top of the cylinder 21, the cylinder pressure sensor 19 are signally connected to the electronic control unit (ECU) 18, and the electronic The control unit 18 is also signally connected with the jet valve 4, the throttle valve 5, and the EGR valve 15, and the electronic control unit 18 receives the sensor signal 17 and controls the throttle valve 5, the jet valve 4, the fuel injector 20, the spark plug 22 and the EGR valve 15, so that The environment in the engine cylinder meets the growth conditions of carbon nanotubes, so as to generate as many carbon nanotubes as possible. The exhaust gas analyzer 13 sends the detected CO concentration to the electronic control unit 18 .
如图2所示，传感器信号17包括排气中的氧含量、排气温度、节气门开度、发动机的转速、排气背压及发动机缸内压力，排气中的氧含量通过氧传感器获取，排气温度通过温度传感器获取，节气门开度通过节气门位置传感器获取，发动机的转速通过转速传感器获取，排气背压通过背压传感器获取，发动机缸内压力通过缸压传感器19获取；氧传感器、温度传感器和背压传感器安装在碳纳米管捕集器16之前的排气道中，节气门位置传感器安装在节气门5处，转速传感器安装在发动机齿轴处；废气涡轮12与三元催化转换器14之间管道上也安装有背压传感器。As shown in FIG. 2 , the sensor signal 17 includes the oxygen content in the exhaust gas, the exhaust gas temperature, the throttle valve opening, the engine speed, the exhaust back pressure and the pressure in the engine cylinder. The oxygen content in the exhaust gas is obtained by the oxygen sensor. , the exhaust temperature is obtained by the temperature sensor, the throttle opening is obtained by the throttle position sensor, the engine speed is obtained by the speed sensor, the exhaust back pressure is obtained by the back pressure sensor, and the pressure in the engine cylinder is obtained by the cylinder pressure sensor 19; The sensor, temperature sensor and back pressure sensor are installed in the exhaust port before the carbon nanotube trap 16, the throttle valve position sensor is installed at the throttle valve 5, and the speed sensor is installed at the engine gear shaft; the exhaust gas turbine 12 and the three-way catalysis A back pressure sensor is also installed on the pipe between the converters 14 .
如图3(a)所示，碳纳米管捕集器16整体呈圆柱状，碳纳米管捕集器16两端分别设置若干电磁铁23和过滤器26；电磁铁23为圆柱状，电磁铁23上缠绕有电磁铁线圈24，且相邻电磁铁23上设置的电磁铁线圈24均不相同，即一个电磁铁23在两端缠绕电磁铁线圈24，另一个电磁铁23在中间位置缠绕电磁铁线圈24，如图3(b)所示；过滤器26为圆柱状，过滤器26内部设有若干长方体状的陶瓷孔塞25，且过滤器26内部设置的相邻陶瓷孔塞25均不相同，即在过滤器26的一处两端设置陶瓷孔塞25，在过滤器26的另一处中间位置设置陶瓷孔塞25，如图3(c)所示。在碳纳米管捕集器16工作过程中，气缸21内的废气先通过电磁铁23，废气中的纳米铁颗粒具有磁性将被吸附在电磁铁线圈24的磁性侧面；相关研究表明碳纳米管的直径为1-2nm、长度为5-100um，具有很大的长径比，陶瓷孔塞25和过滤器26的孔径均为1um，用于过滤掉碳纳米管；当废气通过碳纳米管捕集器16时，废气中的碳纳米管被捕集的同时，未参与反应的纳米铁颗粒也会吸附在电磁铁23上，起到回收利用的作用。As shown in FIG. 3( a ), the carbon nanotube trap 16 has a cylindrical shape as a whole, and a plurality of electromagnets 23 and filters 26 are respectively arranged at both ends of the carbon nanotube trap 16 ; the electromagnet 23 is cylindrical, and the electromagnet The electromagnet coil 24 is wound on the 23, and the electromagnet coils 24 provided on the adjacent electromagnets 23 are different, that is, one electromagnet 23 is wound with the electromagnet coil 24 at both ends, and the other electromagnet 23 is wound at the middle position. The iron coil 24 is shown in FIG. 3(b); the filter 26 is cylindrical, a plurality of cuboid-shaped ceramic hole plugs 25 are arranged inside the filter 26, and the adjacent ceramic hole plugs 25 arranged inside the filter 26 are not The same, that is, a ceramic hole plug 25 is arranged at one end of the filter 26, and a ceramic hole plug 25 is arranged at another middle position of the filter 26, as shown in FIG. 3(c). During the working process of the carbon nanotube trap 16, the exhaust gas in the cylinder 21 first passes through the electromagnet 23, and the nano-iron particles in the exhaust gas have magnetism and will be adsorbed on the magnetic side of the electromagnet coil 24; The diameter is 1-2nm, the length is 5-100um, and has a large aspect ratio. The pore size of the ceramic hole plug 25 and the filter 26 are both 1um, which are used to filter out carbon nanotubes; when the exhaust gas is trapped by carbon nanotubes When the device 16 is turned on, the carbon nanotubes in the exhaust gas are trapped, and the nano-iron particles that do not participate in the reaction will also be adsorbed on the electromagnet 23 to play the role of recycling.
图4为颗粒物提取装置，用于将过滤器26置于碳纳米管收集腔28中，碳纳米管收集腔28一端通入干燥压缩空气29，另一端设置过滤膜27，在干燥压缩空气29的作用下(干燥压缩空气29的流向与碳纳米管捕集器16捕集颗粒物时的气体流速方向相反)，将碳纳米管吹入到碳纳米管收集腔28内，过滤膜27只允许空气通过，最终碳纳米管颗粒在碳纳米管收集腔28内提取出来；同时，纳米铁颗粒以此原理被干燥压缩空气29吹出。4 is a device for extracting particulate matter, which is used to place the filter 26 in the carbon nanotube collection chamber 28. One end of the carbon nanotube collection chamber 28 is fed with dry compressed air 29, and the other end is provided with a filter membrane 27. Under the action (the flow direction of the dry compressed air 29 is opposite to the gas flow direction when the carbon nanotube trap 16 captures particulate matter), the carbon nanotubes are blown into the carbon nanotube collection cavity 28, and the filter membrane 27 only allows air to pass through. , and finally the carbon nanotube particles are extracted from the carbon nanotube collection cavity 28 ; at the same time, the nano iron particles are blown out by the dry compressed air 29 according to this principle.
本发明采用点燃式双燃料发动机的碳纳米管制备装置的工作原理如下：The present invention adopts the working principle of the carbon nanotube preparation device of the ignition type dual-fuel engine as follows:
电子控制单元18控制喷气阀门4打开，天然气贮气瓶1中的天然气经过天然气滤清器2 进入发动机的进气道，与新鲜空气混合后注入气缸21内；打开汽油箱6和汽油滤清器7之间的截止阀，提前与催化剂和促进剂混合好的汽油，经过超声波水浴下经超声处理后混合均匀后，依次经过汽油滤清器7、燃油泵8和喷油器20喷入气缸21内；两种燃料进入气缸21后采用火花式点火或压燃方式引燃可燃混合气体，经过缸内复杂的化学反应，生成的碳纳米管随着废气一起被排出气缸21，废气通过碳纳米管捕集器16后，碳纳米管及少量未燃烧完全的颗粒物会被过滤下，废气再通过ERG阀15，部分废气会重新进入气缸21，起到控制缸内温度及抑制NOx的生成的作用，剩余的大部分废气通过废气涡轮12，使得部分废气余热被回收利用；大部分废气经尾气分析仪13检测之后被三元催化转换器14处理，废气中的CO和HC将被氧化成H 2O和CO 2，使得最终排入大气中的废气只剩下H 2O和CO 2。 The electronic control unit 18 controls the jet valve 4 to open, and the natural gas in the natural gas storage cylinder 1 enters the intake port of the engine through the natural gas filter 2, and is mixed with fresh air and injected into the cylinder 21; open the gasoline tank 6 and the gasoline filter The shut-off valve between 7, the gasoline mixed with the catalyst and the accelerator in advance, after ultrasonic treatment in an ultrasonic water bath, after mixing evenly, is injected into the cylinder 21 through the gasoline filter 7, the fuel pump 8 and the fuel injector 20 in turn. After the two fuels enter the cylinder 21, the combustible gas mixture is ignited by spark ignition or compression ignition. After a complex chemical reaction in the cylinder, the generated carbon nanotubes are discharged from the cylinder 21 together with the exhaust gas, and the exhaust gas passes through the carbon nanotubes. After the trap 16, carbon nanotubes and a small amount of unburned particulate matter will be filtered, and the exhaust gas will pass through the ERG valve 15, and part of the exhaust gas will re-enter the cylinder 21 to control the temperature in the cylinder and inhibit the generation of NOx. Most of the remaining exhaust gas passes through the exhaust gas turbine 12, so that part of the waste heat of the exhaust gas is recycled; most of the exhaust gas is detected by the exhaust gas analyzer 13 and then processed by the three-way catalytic converter 14, and the CO and HC in the exhaust gas will be oxidized into H 2 O and CO 2 , so that only H 2 O and CO 2 are left in the exhaust gas finally discharged into the atmosphere.
发动机气缸21内的温度、氧含量及缸内每个燃烧周期长度对碳纳米管的生成起着至关重要的作用，这些因素必须控制在合适的范围才能保证碳纳米管的正常生长。在双燃料发动机制备碳纳米管的工作过程中，电子控制单元18接收氧传感器和节气门位置传感器的信号对节气门5、喷油器20和喷气阀门4进行控制，进而改变气缸内部燃料的当量比，将当量比控制在1.1-1.2范围内，若当量比小于1.1，则减小节气门开度，增大喷油器阀门开度与喷气阀门开度；若当量比大于1.2，则增大节气门开度，减小喷油器阀门开度与喷气阀门开度；节气门开度(0-50％)改变当量比的同时影响CO浓度，节气门开度越大当量比越小，10％-15％的节气门开度使得当量比在1.1-1.2范围内，能保证CO浓度高于10％；电子控制单元18接收温度传感器、缸压传感器19的信号，根据气缸内部压力和排气温度对气缸21内部的温度进行预估，通过EGR阀15控制进入气缸21内部的废气或火花塞22的点火提前时间或喷油器20和喷气阀门4控制天然气与汽油的消耗量或节气门开度或EGR阀15的开度，均可以对缸内温度进行调节，使其维持在1000-1200℃范围内，若温度低于1000℃，则增大天然气进气量与汽油喷射量的比值或增加点火提前角或增大节气门开度或减小EGR率(减小EGR阀15的开度，减少进入气缸21内部的废气)，若温度高于1200℃，则减小天然气进气量与汽油喷射量的比值或减小点火提前角或减小节气门开度或增加EGR率(增大EGR阀15的开度，增加进入气缸21内部的废气)；电子控制单元18接收转速传感器的信号，控制喷气阀门4、喷油器20和火花塞22，改变喷油量、喷气量和点火时间，进而对发动机的转速进行调控，调节转速后可以改变发动机每个工作循环的时间，进而能对缸内的反应时间进行调控；电子控制单元18接收背压传感器的信号，当碳纳米管捕集器16因为颗粒物数量过多导致堵塞，使得排气背压过大时，电子控制单元18控制喷油器20和喷气阀门4停止燃料供给，结束发动机运转，避免造成发动机及传感器的损坏。因此，使用电子控制单元18对发动机进行控制，可以使得发动机缸内在正常运转的条件下尽可能生成更多的碳纳米管。此外，电子控制单元18 还可以通过控制喷油时刻与缸内进气时刻的同步，控制喷油压力、EGR率和点火时间去抑制缸内的碳烟的生成，保证碳纳米管的纯度。The temperature, oxygen content and the length of each combustion cycle in the engine cylinder 21 play a crucial role in the formation of carbon nanotubes. These factors must be controlled within a suitable range to ensure the normal growth of carbon nanotubes. In the process of preparing carbon nanotubes in the dual-fuel engine, the electronic control unit 18 receives the signals of the oxygen sensor and the throttle valve position sensor to control the throttle valve 5, the fuel injector 20 and the injection valve 4, thereby changing the fuel equivalent in the cylinder Control the equivalence ratio within the range of 1.1-1.2. If the equivalence ratio is less than 1.1, reduce the throttle opening and increase the injector valve opening and the jet valve opening; if the equivalence ratio is greater than 1.2, increase The opening of the throttle valve reduces the opening of the injector valve and the opening of the jet valve; the opening of the throttle valve (0-50%) changes the equivalence ratio and affects the CO concentration, the larger the throttle opening, the smaller the equivalence ratio, 10 The throttle opening of %-15% makes the equivalence ratio in the range of 1.1-1.2, and the CO concentration can be guaranteed to be higher than 10%; the electronic control unit 18 receives the signals from the temperature sensor and the cylinder pressure sensor 19, according to the cylinder internal pressure and exhaust gas. The temperature estimates the temperature inside the cylinder 21, and controls the exhaust gas entering the cylinder 21 through the EGR valve 15 or the ignition advance time of the spark plug 22 or the fuel injector 20 and the jet valve 4 to control the consumption of natural gas and gasoline or the throttle opening. Or the opening of the EGR valve 15, the in-cylinder temperature can be adjusted to maintain it within the range of 1000-1200°C. If the temperature is lower than 1000°C, the ratio of the natural gas intake amount to the gasoline injection amount is increased or increased Ignition advance angle or increase the throttle valve opening or reduce the EGR rate (reduce the opening of the EGR valve 15, reduce the exhaust gas entering the cylinder 21), if the temperature is higher than 1200 ℃, reduce the amount of natural gas intake and gasoline The ratio of the injection amount or reduce the ignition advance angle or reduce the throttle valve opening or increase the EGR rate (increase the opening of the EGR valve 15, increase the exhaust gas entering the cylinder 21); the electronic control unit 18 receives the signal from the speed sensor, Control the jet valve 4, the fuel injector 20 and the spark plug 22, change the fuel injection volume, the injection volume and the ignition time, and then adjust the engine speed. The response time is regulated; the electronic control unit 18 receives the signal of the back pressure sensor, when the carbon nanotube trap 16 is blocked due to the excessive amount of particulate matter, and the exhaust back pressure is too large, the electronic control unit 18 controls the fuel injector 20 and the jet valve 4 stop the fuel supply and end the engine operation to avoid damage to the engine and the sensor. Therefore, by using the electronic control unit 18 to control the engine, it is possible to generate as many carbon nanotubes as possible in the engine cylinder under normal operating conditions. In addition, the electronic control unit 18 can also control the injection pressure, EGR rate and ignition timing to suppress the generation of soot in the cylinder and ensure the purity of carbon nanotubes by controlling the synchronization of fuel injection timing and in-cylinder intake timing.
采用点燃式双燃料发动机的碳纳米管制备装置在使用前，需确定发动机试验的最佳工况，具体为：Before using the carbon nanotube preparation device of the ignition type dual-fuel engine, it is necessary to determine the best working conditions of the engine test, specifically:
(1)选择将某款4100Q型号缸内直喷式汽油机，将其改装成进气道喷射+缸内直喷式双燃料发动机。(1) Choose to convert a certain 4100Q direct-injection gasoline engine into a port-injection + direct-injection dual-fuel engine.
(2)本实例选用的天然气为高硫天然气，含硫量高于4％，汽油为国Ⅴ标准汽油，含硫量<10ppm。(2) The natural gas selected in this example is high-sulfur natural gas with a sulfur content higher than 4%, and the gasoline is National V standard gasoline with a sulfur content <10ppm.
(3)为了确定碳纳米管生成的最佳条件需要先进行发动机试验，碳纳米管生成的主要影响因素为温度、碳源与催化剂，首先通过试验，确定温度与碳源两个因素符合碳纳米管的生成条件。天然气进气量与汽油喷射量的大小及比例、点火提前角、节气门开度及EGR率都会使得发动机缸内的温度及生成产物发生变化，因此，设置天然气与汽油的消耗量(kg/h)比值为：0-1.0，点火提前角为：-12-0℃A，节气门开度为：0-50％，EGR率为：0-20％；通过缸压传感器19采集的信号分析缸内压力，进而对发动机缸内的平均温度进行预测，确定满足温度范围在600-1200℃，保证CO浓度高于10％。(3) In order to determine the optimal conditions for the formation of carbon nanotubes, an engine test needs to be carried out first. The main factors affecting the formation of carbon nanotubes are temperature, carbon source and catalyst. tube generation conditions. The size and ratio of natural gas intake and gasoline injection amount, ignition advance angle, throttle opening and EGR rate will change the temperature in the engine cylinder and the generated products. Therefore, set the consumption of natural gas and gasoline (kg/h ) ratio: 0-1.0, ignition advance angle: -12-0°C A, throttle opening: 0-50%, EGR rate: 0-20%; the cylinder pressure sensor 19 collects the signal to analyze the cylinder The internal pressure, and then the average temperature in the engine cylinder is predicted, and it is determined that the temperature range is 600-1200 ° C, and the CO concentration is guaranteed to be higher than 10%.
(4)基于最佳温度与CO浓度的工况下，改变天然气中硫化氢气体含量(5％-15％)和油溶性氧化铁纳米颗粒数量(0-10000ppm)，控制发动机的转速在1000-3000r/min，发动机运转后对尾气中的颗粒物进行瞬时取样，相同的工况取样五次，利用扫描电镜对颗粒物进行分析，碳纳米管平均生成量最大值时，确定最佳催化剂与促进剂的含量及发动机转速。(4) Based on the optimal temperature and CO concentration, change the hydrogen sulfide gas content (5%-15%) and the number of oil-soluble iron oxide nanoparticles (0-10000ppm) in the natural gas, and control the engine speed at 1000- At 3000r/min, the particulate matter in the exhaust gas was sampled instantaneously after the engine was running. The same working conditions were sampled five times, and the particulate matter was analyzed by scanning electron microscopy. content and engine speed.
通过对产物分析发现，当油溶性氧化铁纳米颗粒与硫化氢气体的含量分别为7000ppm和10％时，检测到的碳纳米管含量最多；同时发现，当缸内温度在600-1000℃时，虽然满足碳纳米管的生长温度，但是碳烟的含量高于碳纳米管的含量，说明此时缸内条件更有利于碳烟的生成，同时减少了碳纳米管的生成。当缸内温度在控制1000℃以上，发现碳烟颗粒的生成减少了，碳纳米管占颗粒物的绝大部分，所以尽量控制缸内温度在1000-1200℃范围内，更加利于碳纳米管的大量生长及保证碳纳米管的纯度。此外，当发动机转速在2000r/min以上时，生成的碳纳米管很少或者几乎没有，这是因为转速过高会导致缸内反应时间过短导致了碳纳米管的生成少；当转速低于2000r/min时，发现颗粒物以碳烟为主，这说明过低转速使得缸内的碳源物质转化成了碳烟，不利于碳纳米管的生成；因此将发动机转速设置为2000r/min。Through the analysis of the product, it was found that when the content of oil-soluble iron oxide nanoparticles and hydrogen sulfide gas was 7000ppm and 10%, respectively, the detected carbon nanotube content was the most; Although the growth temperature of carbon nanotubes is satisfied, the content of soot is higher than that of carbon nanotubes, indicating that the in-cylinder conditions are more conducive to the generation of soot and reduce the generation of carbon nanotubes. When the temperature in the cylinder is controlled above 1000°C, it is found that the generation of soot particles is reduced, and carbon nanotubes account for most of the particles, so try to control the temperature in the cylinder within the range of 1000-1200°C, which is more conducive to the large number of carbon nanotubes. Grow and ensure the purity of carbon nanotubes. In addition, when the engine speed is above 2000r/min, few or no carbon nanotubes are generated, because the high speed will lead to too short in-cylinder reaction time, resulting in less generation of carbon nanotubes; when the speed is lower than At 2000r/min, it was found that the particulate matter was dominated by soot, which indicated that the low speed made the carbon source material in the cylinder converted into soot, which was not conducive to the formation of carbon nanotubes; therefore, the engine speed was set to 2000r/min.
(5)基于碳纳米管的最佳生成工况，建立脉谱图存储于电子控制单元18中，利用电子控制单元18对发动机的运行工况进行闭环控制，使得发动机一直维持在碳纳米管生成的最佳工况。(5) Based on the optimum generation conditions of carbon nanotubes, a map is established and stored in the electronic control unit 18, and the electronic control unit 18 is used to perform closed-loop control on the operating conditions of the engine, so that the engine is always maintained at the carbon nanotube generation state. the best working condition.
确定发动机试验的最佳工况后，制备碳纳米管的具体过程为：After determining the optimal working conditions of the engine test, the specific process of preparing carbon nanotubes is as follows:
(1)将油溶性氧化铁纳米颗粒添入汽油中，经超声波水浴处理使得催化剂和汽油混合更加均匀，保证油溶性氧化铁纳米颗粒含量为7000ppm，天然气选择硫化氢含量为10％的高硫天然气。(1) Add oil-soluble iron oxide nanoparticles into gasoline, and after ultrasonic water bath treatment, the catalyst and gasoline are mixed more uniformly to ensure that the content of oil-soluble iron oxide nanoparticles is 7000ppm, and the natural gas is high-sulfur natural gas with a hydrogen sulfide content of 10%. .
(2)在双燃料发动机工作过程中，高硫天然气采用进气道喷射，与新鲜空气在进气道中先混合后注入气缸21内；含有催化剂的汽油采用缸内直喷的方式喷入气缸，两种燃料的比例控制在天然气/汽油＝0-1.0，且保证相同时刻进入气缸，最后采用火花式点火方式点燃可燃混合气。(2) During the working process of the dual-fuel engine, the high-sulfur natural gas is injected into the intake port, mixed with fresh air in the intake port and then injected into the cylinder 21; the gasoline containing the catalyst is injected into the cylinder by direct injection in the cylinder, The ratio of the two fuels is controlled at natural gas/gasoline=0-1.0, and it is guaranteed to enter the cylinder at the same time, and finally the combustible mixture is ignited by spark ignition.
(3)当点火提前角为-6℃A、天然气与汽油的消耗量(kg/h)比值为0.4-0.5、EGR率为10％、当量比为1.1-1.2和发动机转速为2000r/min时，恰好能够满足缸内温度维持在1000-1200℃范围内，检测的碳纳米管含量最大；基于这一碳纳米管的最佳生成工况，利用电子控制单元18对发动机的运行工况进行反馈控制，使得发动机一直维持在碳纳米管生成的最佳工况。(3) When the ignition advance angle is -6°C A, the ratio of natural gas to gasoline consumption (kg/h) is 0.4-0.5, the EGR rate is 10%, the equivalence ratio is 1.1-1.2, and the engine speed is 2000r/min , just enough to keep the in-cylinder temperature in the range of 1000-1200 °C, and the detected carbon nanotube content is the largest; based on the optimal generation condition of carbon nanotubes, the electronic control unit 18 is used to feedback the operating conditions of the engine Control, so that the engine has been maintained in the best conditions for carbon nanotube generation.
(4)经过缸内复杂的化学反应，生成的碳纳米管随着废气一起被排出气缸21，废气通过碳纳米管捕集器16后，碳纳米管将被捕集，同时在生成碳纳米管的过程中，氧化铁还原成铁催化碳纳米管的生成，有一部分未参与反应的铁形成铁颗粒随着废气排出气缸将被电磁铁23吸附起到回收利用的作用。(4) After the complex chemical reaction in the cylinder, the generated carbon nanotubes are discharged from the cylinder 21 together with the exhaust gas. After the exhaust gas passes through the carbon nanotube trap 16, the carbon nanotubes will be trapped, and at the same time, the carbon nanotubes will be trapped during the generation of carbon nanotubes. In the process, iron oxide is reduced to iron to catalyze the formation of carbon nanotubes, and a part of iron that does not participate in the reaction forms iron particles that will be adsorbed by the electromagnet 23 as the exhaust gas is discharged from the cylinder to play the role of recycling.
(5)电磁铁23与过滤器26均可拆卸，分别将其放入颗粒物提取装置中，经过干燥高压空气29的反吹，铁颗粒和碳纳米管分别从电磁铁线圈24和过滤器26中吹出到收集腔28内，实现二者的收集。(5) Both the electromagnet 23 and the filter 26 can be disassembled, respectively put them into the particle extraction device, and after the backflushing of the dry high-pressure air 29, the iron particles and carbon nanotubes are removed from the electromagnet coil 24 and the filter 26 respectively. Blow out into the collection chamber 28 to realize the collection of the two.
所述实施例为本发明的优选的实施方式，但本发明并不限于上述实施方式，在不背离本发明的实质内容的情况下，本领域技术人员能够做出的任何显而易见的改进、替换或变型均属于本发明的保护范围。The embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or Modifications all belong to the protection scope of the present invention.

Claims (10)

  1. 一种采用点燃式双燃料发动机的碳纳米管制备装置，其特征在于，包括天然气贮气瓶(1)和汽油箱(6)；A carbon nanotube preparation device using an ignition type dual-fuel engine, characterized in that it comprises a natural gas storage cylinder (1) and a gasoline tank (6);
    所述天然气贮气瓶(1)通过管道与气缸(21)的进气道连通，且天然气贮气瓶(1)与进气道连接处设有喷气阀门(4)；气缸(21)的进气道上设有节气门(5)；气缸(21)的排气管上沿排气方向依次设有碳纳米管捕集器(16)、EGR阀(15)和尾气分析仪(13)，且排气管在设置EGR阀(15)处，通过管道与进气道连通；The natural gas storage cylinder (1) is communicated with the air inlet of the cylinder (21) through a pipeline, and a jet valve (4) is provided at the connection between the natural gas storage cylinder (1) and the air inlet; A throttle valve (5) is arranged on the air passage; a carbon nanotube trap (16), an EGR valve (15) and an exhaust gas analyzer (13) are sequentially arranged on the exhaust pipe of the cylinder (21) along the exhaust direction, and The exhaust pipe is communicated with the intake port through a pipe where the EGR valve (15) is provided;
    所述汽油箱(6)通过管道与设置在气缸(21)上的喷油器(20)连通，且汽油箱(6)的管道上设有截止阀；The gasoline tank (6) is communicated with a fuel injector (20) arranged on the cylinder (21) through a pipeline, and a stop valve is provided on the pipeline of the gasoline tank (6);
    所述气缸(21)顶部设有火花塞(22)和缸压传感器(19)；The top of the cylinder (21) is provided with a spark plug (22) and a cylinder pressure sensor (19);
    所述喷气阀门(4)、节气门(5)、尾气分析仪(13)、EGR阀(15)、火花塞(22)、缸压传感器(19)均与电子控制单元(18)信号连接，电子控制单元(18)还接收的信号包括：排气中的氧含量、排气温度、节气门开度、发动机的转速、排气背压和发动机缸内压力。The jet valve (4), the throttle valve (5), the exhaust gas analyzer (13), the EGR valve (15), the spark plug (22), and the cylinder pressure sensor (19) are all signally connected to the electronic control unit (18), and the electronic The control unit (18) also receives signals including: oxygen content in the exhaust gas, exhaust gas temperature, throttle opening, engine speed, exhaust back pressure and engine in-cylinder pressure.
  2. 根据权利要求1所述的采用点燃式双燃料发动机的碳纳米管制备装置，其特征在于，所述碳纳米管捕集器(16)两端分别设置若干电磁铁(23)和过滤器(26)，电磁铁(23)上缠绕有电磁铁线圈(24)，且相邻电磁铁(23)上设置的电磁铁线圈(24)均不相同；过滤器(26)内部设有若干长方体状的陶瓷孔塞(25)，且过滤器(26)内部设置的相邻陶瓷孔塞(25)均不相同。The carbon nanotube preparation device using an ignition type dual-fuel engine according to claim 1, characterized in that, a plurality of electromagnets (23) and filters (26) are respectively provided at both ends of the carbon nanotube trap (16). ), the electromagnet (23) is wound with an electromagnet coil (24), and the electromagnet coils (24) provided on the adjacent electromagnets (23) are different; A ceramic hole plug (25) is provided, and the adjacent ceramic hole plugs (25) arranged inside the filter (26) are different.
  3. 根据权利要求1所述的采用点燃式双燃料发动机的碳纳米管制备装置，其特征在于，所述气缸(21)的排气管上还设有废气涡轮(12)和三效催化转化器(14)，废气涡轮(12)位于尾气分析仪(13)和EGR阀(15)之间，所述尾气分析仪(13)位于废气涡轮(12)和三效催化转化器(14)之间。The device for preparing carbon nanotubes using an ignition-type dual-fuel engine according to claim 1, wherein the exhaust pipe of the cylinder (21) is further provided with an exhaust gas turbine (12) and a three-way catalytic converter (3-way catalytic converter). 14), the exhaust gas turbine (12) is located between the exhaust gas analyzer (13) and the EGR valve (15), the exhaust gas analyzer (13) is located between the exhaust gas turbine (12) and the three-way catalytic converter (14).
  4. 根据权利要求3所述的采用点燃式双燃料发动机的碳纳米管制备装置，其特征在于，所述气缸(21)的进气道上沿进气方向还依次设有空气滤清器(10)、压气机(11)和中冷器(9)，且压气机(11)与废气涡轮(12)连接。The device for preparing carbon nanotubes using an ignition type dual-fuel engine according to claim 3, wherein an air filter (10), an air filter (10), an air filter (10), an air filter (10), an air filter (10), A compressor (11) and an intercooler (9), and the compressor (11) is connected to an exhaust gas turbine (12).
  5. 根据权利要求1所述的采用点燃式双燃料发动机的碳纳米管制备装置，其特征在于，所述喷油器(20)与汽油箱(6)之间沿进油方向还依次设有汽油滤清器(7)和燃油泵(8)。The device for preparing carbon nanotubes using an ignition type dual-fuel engine according to claim 1, characterized in that, between the fuel injector (20) and the gasoline tank (6) along the fuel inlet direction, a gasoline filter is also arranged in sequence. Cleaner (7) and fuel pump (8).
  6. 根据权利要求1所述的采用点燃式双燃料发动机的碳纳米管制备装置，其特征在于，所述天然气贮气瓶(1)与喷气阀门(4)之间沿进气方向还依次设有天然气滤清器(2)和压力调节器(3)。The carbon nanotube preparation device using an ignition type dual-fuel engine according to claim 1, characterized in that, between the natural gas storage cylinder (1) and the jet valve (4) along the air intake direction, natural gas is also arranged in sequence Filter (2) and pressure regulator (3).
  7. 一种根据权利要求1-6任一项所述的采用点燃式双燃料发动机的碳纳米管制备装置制备碳纳米管的方法，其特征在于：A method for preparing carbon nanotubes according to a carbon nanotube preparation device of an ignition type dual-fuel engine according to any one of claims 1-6, characterized in that:
    天然气和新鲜空气混合后注入气缸(21)内，与催化剂混合好的汽油也喷入气缸(21)内，经过缸内反应后，废气通过碳纳米管捕集器(16)后，部分废气通过ERG阀(15)重新进入气缸(21)，剩余的大部分废气通过废气涡轮(12)和三元催化转换器(14)后，排入大气；The natural gas and fresh air are mixed and injected into the cylinder (21), and the gasoline mixed with the catalyst is also injected into the cylinder (21). After the reaction in the cylinder, the exhaust gas passes through the carbon nanotube trap (16), and part of the exhaust gas passes through The ERG valve (15) re-enters the cylinder (21), and most of the remaining exhaust gas is discharged into the atmosphere after passing through the exhaust gas turbine (12) and the three-way catalytic converter (14);
    所述天然气与汽油的消耗量比值为0.4-0.5，所述催化剂为7000ppm的油溶性氧化铁纳米颗粒，所述天然气中含有10％的硫化氢气体；The consumption ratio of the natural gas to gasoline is 0.4-0.5, the catalyst is 7000ppm oil-soluble iron oxide nanoparticles, and the natural gas contains 10% hydrogen sulfide gas;
    缸内反应过程中，发动机转速为2000r/min，缸内温度控制在1000-1200℃范围内，当量比控制在1.1-1.2范围内。During the in-cylinder reaction process, the engine speed was 2000r/min, the in-cylinder temperature was controlled within the range of 1000-1200°C, and the equivalence ratio was controlled within the range of 1.1-1.2.
  8. 根据权利要求7所述的制备碳纳米管的方法，其特征在于，所述当量比的控制过程为：电子控制单元(18)获取排气中的氧含量和节气门开度，对节气门(5)、喷油器(20)和喷气阀门(4)进行控制，进而改变当量比。The method for preparing carbon nanotubes according to claim 7, wherein the control process of the equivalence ratio is as follows: the electronic control unit (18) obtains the oxygen content in the exhaust gas and the opening degree of the throttle valve, and controls the throttle valve (18). 5), the fuel injector (20) and the jet valve (4) are controlled to change the equivalence ratio.
  9. 根据权利要求8所述的制备碳纳米管的方法，其特征在于，所述节气门(5)的开度为10％-15％。The method for preparing carbon nanotubes according to claim 8, characterized in that, the opening degree of the throttle valve (5) is 10%-15%.
  10. 根据权利要求7所述的制备碳纳米管的方法，其特征在于，所述缸内温度的控制过程为：电子控制单元(18)获取排气温度和气缸内部压力，对气缸(21)内部的温度进行预估，通过EGR阀(15)控制进入气缸(21)内部的废气或者火花塞(22)的点火提前时间或者喷油器(20)和喷气阀门(4)控制进气量与汽油喷射量的比值或者节气门开度或者EGR阀(15)的开度，对缸内温度进行调节。The method for preparing carbon nanotubes according to claim 7, wherein the control process of the temperature in the cylinder is: the electronic control unit (18) obtains the exhaust gas temperature and the pressure inside the cylinder, and controls the temperature inside the cylinder (21). The temperature is estimated, and the exhaust gas entering the cylinder (21) or the ignition advance time of the spark plug (22) or the fuel injector (20) and the injection valve (4) are controlled by the EGR valve (15) to control the intake air volume and gasoline injection volume. The ratio of , or the opening of the throttle valve or the opening of the EGR valve (15), adjusts the in-cylinder temperature.
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CN112796896A (en) * 2021-02-04 2021-05-14 江苏大学 Device and method for preparing carbon nano tube by adopting ignition type dual-fuel engine

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