Device and method for removing engine pollutant nitric oxide by using nano-porous carbon

Abstract

The invention discloses a device and a method for removing engine pollutant nitric oxide by using nano-porous carbon, belongs to the technical field of engine tail gas treatment, and solves the technical problems that the pollution control cost is increased when urea is used for removing NOx, and the risk of secondary pollution caused by urea escape is possibly caused. Comprising an engine and an engine ECU, the engine is connected with a turbocharger through an exhaust manifold, the turbocharger is connected with a DOC processor and a DPF processor through an exhaust pipe, the system further comprises an NPC sprayer, an NPC storage device and a high-pressure air source, the NPC sprayer is installed at the position, between the turbocharger and the DOC processor, of the exhaust pipe, the NPC sprayer is sequentially connected with the NPC storage device and the high-pressure air source, and the high-pressure air source is connected with the engine ECU. The engine ECU is electrically connected with the engine and the NPC sprayer. The NPC spraying amount is determined according to the NOx emission amount, the NPC sprayer is controlled to evenly spray NPC into the exhaust pipe according to the NPC spraying amount, the NPC spraying amount is dynamically corrected according to the emission amount obtained after NOx treatment, NOx emission is reduced, and chemical reagents such as urea do not need to be used.

Description

Technical Field

[0001] The present invention relates to the technical field of engine exhaust gas treatment, and more specifically, it relates to a device and method for removing nitrogen oxides, which are engine pollutants, using nanoporous carbon. Background Art

[0002] Engines are widely used in various fields, but the pollutants emitted by them have caused serious harm to the atmospheric environment and humans. As of 2022, the number of motor vehicles in China has exceeded 417 million, among which the national emissions of nitrogen oxides (NOx) from automobiles reached 5.159 million tons, and the emissions of particulate matter (PM) reached 50,000 tons. It is worth noting that the nitrogen oxides (NOx) emitted by diesel vehicles account for more than 80% of the total automobile emissions, and PM accounts for more than 90%. In order to reduce the impact of automobile emissions pollution, the environmental emission regulations for engines have become increasingly strict. In 2023, China fully implemented the more stringent National VI b emission standards. Reducing the emissions of particulate matter (PM) and nitrogen oxides (NOx) from diesel vehicles has become an urgent need.

[0003] Currently, the removal of nitrogen oxides (NOx) from exhaust emissions usually adopts a catalytic method. Based on the selective catalytic reduction technology (SCR) of urea reduction, NOx undergoes a catalytic reaction with a catalyst. NOx is reduced to nitrogen and water vapor, thereby reducing the emissions of NOx. However, to meet the strict emission standards, the NOx conversion rate must exceed 90%, which often requires a large amount of urea injection. Increasing the amount of urea used will not only increase the pollution control cost but also may face the risk of secondary pollution caused by urea escape.

[0004] In recent years, due to advantages such as simple preparation, large adsorption capacity, and low price, carbon-based adsorption materials have become a research hotspot in the environmental protection field. Therefore, using carbon-based adsorption materials to treat NOx emissions from automobiles is a highly promising automobile exhaust pollution control technology. In existing research, nanoporous carbon (NPC) has been widely used to remove organic (PAHs, VOCs, etc.) or inorganic (NOx, SO 2 etc.) pollutants. NPC has become an ideal material for treating automobile pollutants due to its high specific surface area, large adsorption capacity, excellent thermal conductivity, and adjustable microporous structure and surface properties. Summary of the Invention

[0005] The technical problem to be solved by the present invention is in view of the above-mentioned deficiencies of the prior art. The first object of the present invention is to provide a device for removing nitrogen oxides, which are engine pollutants, using nanoporous carbon.

[0006] The second object of the present invention is to provide a method for removing nitrogen oxides, which are engine pollutants, using nanoporous carbon.

[0007] To achieve the above-mentioned first object, the present invention provides a device for removing nitrogen oxides, which are engine pollutants, by using nanoporous carbon. The device includes an engine and an engine ECU. The engine is connected to a turbocharger through an exhaust manifold, and the turbocharger is connected to a DOC processor and a DPF processor through an exhaust pipe. It is characterized in that it further includes an NPC sprayer, an NPC reservoir, and a high-pressure gas source. The NPC sprayer is installed on the exhaust pipe between the turbocharger and the DOC processor. The NPC sprayer is sequentially connected to the NPC reservoir and the high-pressure gas source. The engine ECU is electrically connected to the engine and the NPC sprayer.

[0008] As a further improvement, the distance from the NPC sprayer to the DOC processor is 0.3 to 1 meter.

[0009] Further, the NPC reservoir is located above the NPC sprayer, and the NPC reservoir is vertically connected to the NPC sprayer. The distance from the NPC reservoir to the NPC sprayer is 0.5 to 1 meter.

[0010] Further, the high-pressure gas source is located above the NPC reservoir, and the high-pressure gas source is vertically connected to the NPC reservoir. The distance from the high-pressure gas source to the NPC reservoir is 0.3 to 0.5 meter.

[0011] Further, the DOC processor and the DPF processor are integrated.

[0012] Further, a NOx sensor is provided at the output end of the DPF processor. The engine ECU is electrically connected to the NOx sensor.

[0013] Further, the NPC sprayer includes an outer pipe. Connecting flanges are respectively provided at both ends of the outer pipe. An inner pipe is provided inside the outer pipe. One end of the inner pipe extends to the outside of one end of the outer pipe and is provided with a spray head. The other end of the inner pipe vertically passes through the outer pipe and is sequentially provided with a solenoid valve and a connector connecting to the NPC reservoir. The engine ECU is electrically connected to the solenoid valve.

[0014] Further, a mixing pipe is provided on the exhaust pipe between the NPC sprayer and the DOC processor. A spiral blade is provided in the middle of the mixing pipe.

[0015] To achieve the above-mentioned second object, the present invention provides a method for removing nitrogen oxides, which are engine pollutants, by using nanoporous carbon. The method includes the following steps:

[0016] Step 1. The engine ECU collects the engine speed, torque, intake air flow rate, and fuel mass flow rate.

[0017] Step 2. Determine the engine operating conditions based on the rotational speed and torque, and determine the NOx emissions based on the intake air flow rate and fuel mass flow rate;

[0018] Step 3. Determine the NPC injection amount based on the NOx emissions;

[0019] Step 4. Control the operation of the NPC sprayer according to the NPC injection amount to evenly spray NPC into the exhaust pipe;

[0020] Step 5. The engine ECU collects the emissions after NOx treatment through the NOx sensor, and dynamically corrects the NPC injection amount according to the emissions after NOx treatment.

[0021] As a further improvement, the calculation formula for determining the NPC injection amount based on the NOx emissions is as follows:

[0022]

[0023] Among them, k1 is the adsorption capacity of NPC for NOx, and k2 is the adsorption efficiency of NPC for NOx.

[0024] Beneficial effects

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The present invention calculates the NOx emissions through engine parameters, determines the NPC injection amount based on the NOx emissions, controls the NPC sprayer to evenly spray NPC into the exhaust pipe according to the NPC injection amount, and dynamically corrects the NPC injection amount according to the emissions after NOx treatment, so as to reduce the NOx emissions. Compared with the traditional technology, the present invention does not need to use a large amount of chemical reagents such as urea, avoids the risk of secondary pollution, reduces the pollution control cost, and does not require complex equipment transformation, and has a wide application prospect. Description of the drawings

[0027] Figure 1 It is a schematic structural diagram of the present invention;

[0028] Figure 2 It is a schematic structural diagram of the NPC sprayer in the present invention;

[0029] Figure 3 It is a schematic structural diagram of the mixing pipe in the present invention;

[0030] Figure 4 It is a purification flow chart of the tail gas emission of the present invention;

[0031] Figure 5 It is the catalytic oxidation of nanoporous carbon adsorbed in the DPF catalyst and nitric oxide and nitrogen dioxide;

[0032] Figure 6 It is a diagram of the adsorption and oxidation mechanism of nitric oxide and nitrogen dioxide;

[0033] Figure 7 It is a schematic diagram of the adsorption of nitrogen oxides by nanoporous carbon;

[0034] Figure 8 It is a partial reaction path of nitrogen dioxide and nanoporous carbon;

[0035] Figure 9 It is a partial reaction path of nitric oxide and nanoporous carbon.

[0036] Among them: 1 - engine, 2 - engine ECU, 3 - exhaust manifold, 4 - turbocharger, 5 - exhaust pipe, 6 - DOC processor, 7 - DPF processor, 8 - NPC sprayer, 9 - NPC reservoir, 10 - high-pressure gas source, 11 - NOx sensor, 12 - outer pipe, 13 - connecting flange, 14 - inner pipe, 15 - spray head, 16 - solenoid valve, 17 - connector, 18 - mixing pipe, 19 - spiral blade, 20 - intake pipe, 21 - air filter, 22 - air flow meter, 23 - intercooler, 24 - EGR, 25 - EGR valve, 26 - intake manifold, 27 - oil pump, 28 - fuel consumption meter, 29 - fuel tank. Specific embodiments

[0037] The present invention will be further described below with reference to specific embodiments in the accompanying drawings.

[0038] Refer to Figures 1 to 9 , a device for removing nitrogen oxides, which are engine pollutants, by using nanoporous carbon, includes an engine 1 and an engine ECU 2. The engine 1 is connected to a turbocharger 4 through an exhaust manifold 3, and the turbocharger 4 is connected to a DOC processor 6 and a DPF processor 7 through an exhaust pipe 5. It further includes an NPC sprayer 8, an NPC reservoir 9, and a high-pressure gas source 10. The NPC sprayer 8 is installed on the exhaust pipe 5 between the turbocharger 4 and the DOC processor 6. The NPC sprayer 8 is sequentially connected to the NPC reservoir 9 and the high-pressure gas source 10. The engine ECU 2 is electrically connected to the engine 1 and the NPC sprayer 8.

[0039] As Figure 1As shown in the figure, air is delivered through the intake pipe 20 to the air filter 21 to filter out dust and particulate impurities therein, and then enters the air flow meter 22 to measure the amount of air entering the engine 1. Subsequently, the air is compressed by the turbocharger 4 to increase the intake density and pressure and the air intake of the engine. The temperature of the air compressed by the turbocharger 4 rises. Therefore, it is necessary to cool it with the intercooler 23 to further increase the intake density. The cooled air enters the engine 1 through the intake manifold 26, mixes with fuel in the cylinder and burns to generate high-temperature and high-pressure exhaust gas, which is discharged through the exhaust manifold 3. After entering the turbocharger 4, the temperature and pressure of the exhaust gas decrease, and then it is discharged through the exhaust pipe 5. Among them, an EGR pipe is provided between the exhaust manifold 3 and the intake manifold 26, and an EGR 24 and an EGR valve 25 are provided on the EGR pipe. The fuel in the fuel tank 29 enters the fuel pump 27 after passing through the fuel consumption meter 28 and finally enters the engine 1. The engine ECU 2 is electrically connected to the fuel pump 27.

[0040] Specifically, the distance from the NPC sprayer 8 to the DOC processor 6 is 0.3 to 1 meter. The NPC reservoir 9 is located above the NPC sprayer 8, and the NPC reservoir 9 is vertically connected to the NPC sprayer 8. The distance from the NPC reservoir 9 to the NPC sprayer 8 is 0.5 to 1 meter. The high-pressure gas source 10 is located above the NPC reservoir 9, and the high-pressure gas source 10 is vertically connected to the NPC reservoir 9. The distance from the high-pressure gas source 10 to the NPC reservoir 9 is 0.3 to 0.5 meter. With the above layout distribution, the NPC sprayed into the aftertreatment system is fully mixed with the exhaust gas and is adapted to the space of the engine compartment.

[0041] The DOC processor 6 and the DPF processor 7 are integrated. An NOx sensor 11 is provided at the output end of the DPF processor 7. The engine ECU 2 is electrically connected to the NOx sensor 11.

[0042] The NPC sprayer 8 includes an outer pipe 12. Connecting flanges 13 are respectively provided at both ends of the outer pipe 12. An inner pipe 14 is provided inside the outer pipe 12. One end of the inner pipe 14 extends to the outside of one end of the outer pipe 12 and is provided with a spray head 15. The other end of the inner pipe 14 vertically passes through the outer pipe 12 and is successively provided with a solenoid valve 16 and a connector 17 connecting to the NPC reservoir 9. The engine ECU 2 is electrically connected to the solenoid valve 16.

[0043] Further, a mixing pipe 18 is provided on the exhaust pipe 5 between the NPC sprayer 8 and the DOC processor 6. A spiral blade 19 is provided in the middle of the mixing pipe 18, which can make the exhaust gas and NPC mix more evenly.

[0044] A method for removing nitrogen oxides, engine pollutants, by using nanoporous carbon includes the following steps:

[0045] Step 1. The engine ECU 2 collects the engine speed, torque, intake air flow rate, and fuel mass flow rate of the engine 1;

[0046] Step 2. Determine the engine operating conditions based on the engine speed and torque, and determine the NOx emission amount based on the intake air flow rate and fuel mass flow rate (calculating the NOx emission amount based on the intake air flow rate and fuel mass flow rate is a prior art);

[0047] Step 3. Determine the NPC injection amount based on the NOx emission amount;

[0048] Step 4. Control the NPC sprayer 8 to work according to the NPC injection amount to evenly spray NPC into the exhaust pipe 5;

[0049] Step 5. The engine ECU 2 collects the emission amount after NOx treatment through the NOx sensor 11, and dynamically corrects the NPC injection amount according to the emission amount after NOx treatment.

[0050] The calculation formula for determining the NPC injection amount based on the NOx emission amount is as follows:

[0051]

[0052] Among them, k1 is the adsorption capacity of NPC for NOx, k1 = 0.3 g / g, and k2 is the adsorption efficiency of NPC for NOx, k2 = 0.9.

[0053] When the engine ECU 2 detects that the engine is in the idle operating condition, the NOx emission amount is relatively low, ranging from 5.75 g / h to 23 g / h, and the calculated NPC injection amount is from 21.3 g / h to 85.2 g / h; when the engine ECU 2 detects that the engine is in the low to medium speed and low to medium load operating conditions, the NOx emission amount is from 11.5 g / h to 57.5 g / h, and the calculated NPC injection amount is from 42.6 g / h to 213 g / h; when the engine ECU 2 detects that the engine is in the high speed and high load operating conditions, the NOx emission amount is from 23 g / h to 115 g / h, and the calculated NPC injection amount is from 85.2 g / h to 426 g / h; when the engine ECU 2 detects that the engine is in the cold start operating condition, the NOx emission amount is from 11.5 g / h to 57.5 g / h, and the calculated NPC injection amount is from 42.6 g / h to 213 g / h; when the engine ECU 2 detects that the engine is in the transient operating condition, the NOx emission amount is from 23 g / h to 172.5 g / h, and the calculated NPC injection amount is from 85.2 g / h to 638.9 g / h.

[0054] The NPC pressurizes the NPC storage 9 from the high-pressure gas source 10, pushes the NPC into the NPC sprayer 8 and realizes uniform spraying. The engine ECU2 controls the NPC sprayer 8 to spray the calculated injection amount of NPC into the DPF processor 7; after further mixing with the NOx entering the DPF processor 7, due to the high surface area and developed pore structure characteristics of the NPC, the NOx is adsorbed. After the adsorption process ends, the NPC adsorbed with NOx, with the help of the catalyst in the DPF processor 7, causes the oxidation reaction of NOx and NPC.

[0055] As Figure 5 shown, the NPC sprayer sprays the NPC into the DPF processor 7 to form an adsorption bed layer. The NPC adsorbs the NOx entering the DPF processor 7 by virtue of its porous and high specific surface area characteristics; with the help of the catalyst in the DPF processor 7, the redox reaction occurs between NOx and NPC, causing nitric oxide (NO) and nitrogen dioxide (NO 2 ) to react to generate nitrogen (N 2 ) and carbon dioxide (CO 2 ), reducing the emission of NOx. The main reactions occurring in this process are: NO 2 (g)+C NPC (s)→N 2 (g)+CO 2 (g), NO(g)+C NPC (s)→N(g)+CO(g), NO 2 (g)+2CO(g)→N(g)+2CO 2 (g), NO(g)+CO(g)→N(g)+CO 2 (g), N(g)+N(g)→N 2 (g).

[0056] Example 1:

[0057] In this example, under the engine idle condition, when the NOx emission is 14 g / h, the engine ECU2 processes according to the collected information and controls the amount of NPC sprayed by the NPC sprayer to be 52 g / h. After treatment, the NOx emission is 1.4 g / h.

[0058] Example 2:

[0059] In this example, under the engine low-medium speed and low-medium load conditions, when the NOx emission is 34 g / h, the engine ECU2 processes according to the collected information and controls the amount of NPC sprayed by the NPC sprayer to be 126 g / h. After treatment, the NOx emission is 3.4 g / h.

[0060] Example 3:

[0061] In this embodiment, when the engine is in a high-speed and high-load operating condition, the NOx emission is 69 g / h. The engine ECU2 processes the information collected and controls the injection amount of NPC injected by the NPC injector to be 255 g / h. After treatment, the NOx emission is 6.21 g / h.

[0062] Embodiment 4:

[0063] In this embodiment, when the engine is in a transient operating condition, the NOx emission is 100 g / h. The engine ECU2 processes the information collected and controls the injection amount of NPC injected by the NPC injector to be 370 g / h. After treatment, the NOx emission is 9 g / h.

[0064] Embodiment 5:

[0065] In this embodiment, when the distance from the NPC injector to the after-treatment system is 0.3 m, the distance from the NPC injector to the NPC storage is 0.5 m, and the distance from the NPC storage to the high-pressure gas source is 0.3 m, the mixing of NPC and NOx is relatively uniform. Specifically, when the engine is in a low and medium speed operating condition, the NOx emission is 30 g / h, and the emission after treatment is 4.5 g / h.

[0066] Embodiment 6:

[0067] In this embodiment, when the distance from the NPC injector to the after-treatment system is 0.5 m, the distance from the NPC injector to the NPC storage is 0.5 m, and the distance from the NPC storage to the high-pressure gas source is 0.3 m, the mixing of NPC and NOx is uniform. Specifically, when the engine is in a low and medium speed operating condition, the NOx emission is 30 g / h, and the emission after treatment is 3 g / h.

[0068] The above are only the preferred embodiments of the present invention. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which will not affect the implementation effect of the present invention and the practicality of the patent.

Claims

1. A device for removing nitrogen oxides, an engine pollutant, by using nanoporous carbon, comprising an engine (1) and an engine ECU (2), wherein the engine (1) is connected to a turbocharger (4) via an exhaust manifold (3), and the turbocharger (4) is connected to a DOC processor (6) and a DPF processor (7) via an exhaust pipe (5), characterized in that: It also includes an NPC sprayer (8), an NPC reservoir (9), and a high-pressure air source (10); the NPC sprayer (8) is installed in the exhaust pipe (5) between the turbocharger (4) and the DOC processor (6); the NPC sprayer (8) is connected to the NPC reservoir (9) and the high-pressure air source (10) in sequence; and the engine ECU (2) is electrically connected to the engine (1) and the NPC sprayer (8).

2. The device for removing nitrogen oxides from engine pollutants using nanoporous carbon according to claim 1, characterized in that: The distance between the NPC sprayer (8) and the DOC processor (6) is 0.3 to 1 meter.

3. The device for removing nitrogen oxides from engine pollutants using nanoporous carbon according to claim 1, characterized in that: The NPC reservoir (9) is located above the NPC sprayer (8), and the NPC reservoir (9) is vertically connected to the NPC sprayer (8), and the distance from the NPC reservoir (9) to the NPC sprayer (8) is 0.5 to 1 meter.

4. The device for removing nitrogen oxides from engine pollutants using nanoporous carbon according to claim 1, characterized in that: The high-pressure gas source (10) is located above the NPC reservoir (9), and the high-pressure gas source (10) is vertically connected to the NPC reservoir (9), and the distance from the high-pressure gas source (10) to the NPC reservoir (9) is 0.3 to 0.5 meters.

5. The device for removing nitrogen oxides from engine pollutants using nanoporous carbon according to claim 1, characterized in that: The DOC processor (6) and the DPF processor (7) are integrated into one.

6. The device for removing nitrogen oxides from engine pollutants using nanoporous carbon according to claim 1, characterized in that: The output end of the DPF processor (7) is provided with a NOx sensor (11), and the engine ECU (2) is electrically connected to the NOx sensor (11).

7. A device for removing nitrogen oxides from engine pollutants using nanoporous carbon according to any one of claims 1 to 6, characterized in that: The NPC sprayer (8) comprises an outer tube (12), both ends of the outer tube (12) are respectively provided with connecting flanges (13), an inner tube (14) is provided inside the outer tube (12), one end of the inner tube (14) extends to the outside of one end of the outer tube (12) and is provided with a spray head (15), the other end of the inner tube (14) vertically passes through the outer tube (12) and is provided with a solenoid valve (16) and a connector (17) connected to the NPC reservoir (9) in sequence, and the engine ECU (2) is electrically connected to the solenoid valve (16).

8. The device for removing nitrogen oxides from engine pollutants using nanoporous carbon according to claim 7, characterized in that: The exhaust pipe (5) between the NPC sprayer (8) and the DOC processor (6) is provided with a mixing pipe (18), and a spiral blade (19) is provided in the middle of the mixing pipe (18).

9. A method for removing engine pollutant nitrogen oxides using nanoporous carbon, characterized in that: The following steps are involved: Step 1. The engine ECU (2) collects the speed, torque, intake air flow and fuel mass flow of the engine (1); Step 2. Determine the engine operating condition according to the speed and torque, and determine the NOx emission according to the intake air flow rate and the fuel mass flow rate; Step 3. Determine the NPC injection amount according to NOx emissions; Step 4. Control the NPC sprayer (8) to spray the NPC uniformly into the exhaust pipe (5) according to the NPC injection amount; Step 5. The engine ECU (2) collects the NOx-treated emission through the NOx sensor (11), and dynamically corrects the NPC injection amount according to the NOx-treated emission.

10. The method for removing engine pollutant nitrogen oxides by using nanoporous carbon according to claim 9, characterized in that: The calculation formula for determining the NPC injection amount based on NOx emissions is as follows: Among them, k1 is the adsorption capacity of NPC for NOx, and k2 is the adsorption efficiency of NPC for NOx.

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