CN116272364A - SCR urea aqueous solution spraying visualization device and method for simulating real exhaust environment - Google Patents
SCR urea aqueous solution spraying visualization device and method for simulating real exhaust environment Download PDFInfo
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- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 125
- 238000012800 visualization Methods 0.000 title claims abstract description 31
- 239000007864 aqueous solution Substances 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 title claims abstract description 12
- 238000005507 spraying Methods 0.000 title claims description 7
- 238000002347 injection Methods 0.000 claims abstract description 33
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- 239000003344 environmental pollutant Substances 0.000 claims description 5
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9431—Processes characterised by a specific device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9495—Controlling the catalytic process
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2067—Urea
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Abstract
The invention discloses an SCR urea aqueous solution spray visualization device and method for a simulated real exhaust environment, relates to the technical field of SCR denitration, and aims to simulate tail gas of a real engine by a gas distribution supply system, further simulate the exhaust condition of the real engine and measure target gas flow, temperature and NO by a pretreatment pipeline system x The concentration, SCR urea injection system sprays quantitative urea solution to adopt visualization device, urea nozzle department is provided with heat exchanger, detecting system detects the concentration of the target gas of sampling point department. The urea injection device is simple in structure and easy to install, and can realize accurate control of urea injection rate by adjusting the urea nozzle; through accurately mastering the design of a mixer, atomization and evaporation of urea aqueous solution with different temperatures and flow rates and the influence characteristics of urea crystallization, the forward development of an SCR urea aqueous solution injection system is realized by combining numerical calculation with multi-parameter collaborative optimization, and the method is obtainedHigh NO x A novel SCR injection system with conversion efficiency and low crystallization performance.
Description
Technical Field
The invention relates to the technical field of SCR denitration, in particular to an SCR urea aqueous solution spraying visualization device and method for simulating a real exhaust environment.
Background
The SCR system is an indispensable aftertreatment technical scheme for reducing NOx emission of an engine, urea aqueous solution is sprayed into an exhaust pipe, spray pyrolysis is carried out to obtain NH3 serving as a reducing agent, NOx is converted into nitrogen and water under the action of a catalyst, and NOx is removed. At present, the demand of the SCR post-treatment system in the domestic market is large every year, the development of the high-performance SCR post-treatment system is urgently needed, the barrier is broken through in the aspects of key parts and core technology of a short plate of a urea injection system, a complete independent industrial chain of the SCR post-treatment system is built, and the dependence on foreign core parts is reduced.
The problem of SCR aftertreatment systems to increase NOx conversion efficiency and reduce urea crystallization is an international challenge in the development of such systems. At present, most of research and development of SCR systems of enterprises in China are based on reverse engineering research and development processes of widely used products such as Bosch SCR systems, kangming Si SCR systems and the like in the market, theoretical guidance of forward design is lacking, and the low NOx conversion efficiency and urea crystallization of the systems become technical bottlenecks to be solved. The research working conditions of the urea injection spray test developed at present are greatly different from the actual engine exhaust emission environment working conditions, the numerical simulation and theoretical research lack effective test data support, and further lack basic research on the physical and chemical processes such as urea spray atomization, evaporation, pyrolysis, liquid film deposition and crystallization in an actual SCR aftertreatment system, the theoretical support is lacking in the aspects of effectively improving NOx conversion efficiency and avoiding system crystallization, and key core technical innovation and breakthrough of the system are difficult to realize, so that the difference exists between a domestic SCR system and an international brand technology, and the international difficult problem of urea crystallization is one of main reasons that the international difficult problem of urea crystallization is not effectively solved.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides an SCR urea aqueous solution spray visualization device and method for simulating a real exhaust environment, so as to solve the problems in the prior art.
The present invention achieves the above technical object by the following means.
An SCR urea aqueous solution spray visualization device for simulating a real exhaust environment comprises a gas distribution supply system, a pretreatment pipeline system, a urea injection system and a detection system; the gas distribution supply system, the pretreatment pipeline system, the urea injection system and the detection system are sequentially connected; the gas distribution supply system is used for providing the simulated tail gas meeting the requirements; the pretreatment pipeline system heats the simulated exhaust to enable the simulated exhaust to have the same exhaust emission temperature as the actual engine exhaust emission temperature; the urea injection system injects urea solution into the tail gas to be treated by the pretreatment pipeline system and then catalyzes the tail gas to convert NOx into N 2 And H 2 O; the detection system is used for detecting the concentration of pollutants in the tail gas treated by the urea injection system.
In the above scheme, the gas distribution supply system comprises a NO bottle and NO 2 A bottle, an air bottle and a surge tank; the NO bottle and NO 2 The air bottle and the air bottle are communicated with the surge tank through pipelines, and mixed gas is processed through the surge tank; the surge tank is provided with a NO sensor I and a NO 2 The pressure stabilizing tank is connected with the pretreatment pipeline system through a pipeline, and the pipeline is further provided with a valve IV and a one-way valve IV.
In the scheme, the pretreatment pipeline system comprises a flowmeter, an electric heater, a thermocouple and a temperature control flange; the mixed gas of the gas distribution supply system enters a gas transmission pipeline in the pretreatment pipeline system, a flowmeter, an electric heater, a thermocouple and a temperature control flange are sequentially arranged on the gas transmission pipeline, and an electric heating wire is arranged in the electric heater.
In the above scheme, the urea injection system comprises a urea nozzle, a heat exchanger and a visualization cavity; the main pipeline of the pretreatment pipeline system is connected with a visualization cavity, a urea nozzle is arranged in the visualization cavity, the heat exchanger is connected with the urea nozzle, the urea nozzle is externally connected with an outlet of a urea pump, and an inlet of the urea pump is connected with a urea tank;
in the above scheme, the detection system comprises an SCR mixer, an SCR catalyst, and NH 3 Sensor I, NH 3 Sensor II, NO 2 The device comprises a sensor II, a tail gas recovery tank and a pressure gauge III; the visual cavity is sequentially connected with an SCR mixer and an SCR catalyst, the rear of the SCR catalyst is connected with an exhaust gas recovery tank, and the exhaust gas recovery tank is provided with a pressure gauge III; an NH3 sensor I is arranged between the SCR mixer and the SCR catalyst, and an NH3 sensor II, an NO sensor II and NO are arranged between the SCR catalyst and the tail gas recovery tank 2 And a sensor II.
In the scheme, a valve I and a one-way valve I are arranged on a connecting pipeline of the NO bottle and the surge tank; the NO 2 The connecting pipeline of the bottle and the pressure stabilizing tank is provided with a valve II and a one-way valve II; the connecting pipeline of the air bottle and the surge tank is provided with a valve III and a one-way valve III.
In the scheme, the heat exchanger is connected with the urea nozzle, the urea nozzle changes the urea injection angle, and the urea solution supply pump is provided with the pressure gauge II.
In the scheme, an inlet of the mixer is in threaded connection with the visual cavity through the movable joint I, and an outlet of the mixer is in threaded connection with the SCR catalyst through the movable joint II; rubber gaskets are arranged in the movable joint I and the movable joint II.
In the above scheme, the NO sensor I and NO 2 Sensor I, flowmeter, electric heater, thermocouple, temperature control flange, heat exchanger, NH3 sensor I, NH 3 Sensor II, NO 2 The sensor II, the pressure gauge I, the pressure gauge II and the pressure gauge III are all electrically connected with the control unit.
The working method of the SCR urea aqueous solution spray visualization device simulating the real exhaust environment comprises the following steps:
the control unit controls the NO bottle and the NO according to the proportion of the NOx in the actual engine operation condition 2 The opening of valves of the air bottle and the air bottle, and inputting the gas into a pressure stabilizing tank for mixing, so as to obtain proper pseudo-tail gas, and taking the concentration of NOx at the moment as initial concentration;
the simulated tail gas is sent to a pretreatment pipeline system, the flow of the gas is measured in advance by a flowmeter before the mixed gas flows through an electric heater, then the temperature is measured by a thermocouple, the temperature data is converted into an electric signal when the mixed gas flows through a temperature control flange, and the electric signal is input into a control unit, so that the resistance power is controlled, the air is kept at the required temperature, and the mixed gas is more similar to the actual tail gas emission environment working condition of an engine;
the obtained gas is sent into a urea injection system, fully mixed with urea solution sprayed by a urea nozzle and then enters an SCR catalyst, and catalytic reaction is carried out inside the SCR catalyst to convert NOx into N 2 And H2O; meanwhile, the atomization condition of the urea solution at the nozzle can be observed through a visual cavity in the spraying system, so that the urea nozzle can be adjusted, and urea crystallization is avoided;
the tail gas after reaction finally enters a detection system and passes through NH 3 Sensor II, NO sensor II and NO 2 The sensor II obtains the final concentration of pollutants in the treated tail gas, and the conversion efficiency of the system and the utilization rate of urea can be obtained by comparing the initial concentration obtained previously with the final concentration at the moment;
and the reacted product is recovered into a tail gas recovery tank, so that the pollution to the atmosphere is avoided.
The invention has the beneficial effects that:
1. compared with the direct use of waste gas, the device of the invention has the advantages of simpler control and installation, lower cost, cleaner air and capability of avoiding any optical disturbance in the spray characterization process.
2. According to the invention, the research working condition of the urea injection spray test is relatively similar to the working condition of the actual engine exhaust emission environment, and the system adopts the visual device to facilitate the observation of the urea atomization effect, so that the urea nozzle is optimized, the formation of crystal sediment is avoided or reduced, and the purpose of improving the NOX conversion efficiency is achieved.
3. The gas distribution supply system has the function of simulating the tail gas condition of a real engine.
4. The pretreatment pipeline system of the invention enables the mixed gas to be more similar to the actual tail gas emission environment working condition of the engine.
5. The urea injection device is simple in structure and easy to install, and can realize accurate control of urea injection rate by adjusting the urea nozzle; through accurately mastering the design of a mixer, atomization and evaporation of urea aqueous solution with different temperatures and flow rates and the influence characteristics of urea crystallization, the forward development of an SCR urea aqueous solution injection system is realized by combining numerical calculation with multi-parameter collaborative optimization, and high NO is obtained x A novel SCR injection system with conversion efficiency and low crystallization performance.
Drawings
FIG. 1 is a schematic diagram of an SCR urea aqueous solution spray visualization device for a pseudo-real exhaust environment according to an embodiment;
FIG. 2 is a schematic illustration of the piping involved in FIG. 1;
FIG. 3 is a schematic diagram of a urea injection system (90 degree tilt angle);
FIG. 4 is a schematic diagram of a urea injection system (45 degree tilt angle);
fig. 5 is a cross-sectional view of an SCR mixer module.
Reference numerals:
1-a control unit; 2-NO bottle 3-NO 2 A bottle; 4-an air bottle; 5-a surge tank; 6-valve I; 7-a one-way valve I; 8-valve II; 9-a one-way valve II; 10-valve III; 11-a one-way valve III; 12-valve IV; 13-a one-way valve IV; a 14-NO sensor I; 15-NO 2 A sensor I; 16-pressure gauge I; 17-a flow meter; 18-an electric heater; 19-an electric heating wire; 20-thermocouple; 21-a temperature control flange; a 22-urea nozzle; 23-heat exchanger; 24-visualizing the cavity; 25-urea pump; 26-urea tank; 27-manometer ii; a 28-SCR mixer; 29-SCR catalyst; 30-NH 3 A sensor I; 31-NH 3 A sensor II; a 32-NO sensor II; 33-NO 2 A sensor II; 34-a tail gas recovery tank; 35-manometer III; 36-movable joint I; 37-union II; 38-a rubber gasket I; 39-rubber gasket II.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
In the description of the present invention, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
An SCR urea aqueous solution spray visualization device for simulating a real exhaust environment comprises a gas distribution supply system, a pretreatment pipeline system, a urea injection system and a detection system; the gas distribution supply system is sequentially connected with the pretreatment pipeline system, the urea injection system and the detection system.
According to the invention, the gas distribution supply system comprises a NO bottle 2 and NO 2 A bottle 3, an air bottle 4 and a surge tank 5; the NO bottle 2, NO 2 The 3 bottles and the air bottle 4 are connected with the surge tank 5, and the mixed gas is processed by the surge tank 5; the surge tank 5 is provided with a NO sensor I14, a NO2 sensor I15 and a pressure gauge I16.
NO bottle 2, NO 2 The bottle 3 and the air bottle 4 are provided with valves and one-way valves capable of controlling the opening and closing of the gases, the air pipes of the three gases are respectively connected into the pressure stabilizing tank for mixing, the opening of the valves is controlled by a control unit in the whole mixing and distributing process, and the valves IV and the one-way valves IV are arranged at the tail ends of the system pipelines so as to achieve the purposes of opening and closing the whole system and preventing backflow. The gas distribution supply system has the function of simulating the tail gas condition of a real engine.
The pretreatment piping system comprises a flowmeter 17, an electric heater 18, a thermocouple 20 and a temperature control flange 21; the mixed gas of the gas distribution system enters a pipeline, and a flowmeter 17, an electric heater 18, a thermocouple 20 and a temperature control flange 21 are sequentially arranged on the pipeline; in the system, a flowmeter 17, an electric heater 18, a thermocouple 20 and a temperature control flange 21 are all connected with a control unit, the mixed gas flows through the flowmeter before flowing through the electric heater, the gas temperature is recorded by the thermocouple after flowing through the electric heater, and in order to control the current applied to the electric heating element, a temperature control flange is arranged on a pipeline. The sensor of the control flange measures the temperature and converts it into an electrical signal which is input to the control unit 1. This device controls the resistive power to maintain the air at the desired temperature. The system mainly aims to enable the mixed gas to be closer to the actual tail gas emission environment working condition of the engine.
The urea injection system comprises a urea tank 26, a urea pump 25, a pressure gauge ii 27, a heat exchanger 23, a urea nozzle 22 and a visualization cavity 24. The gas treated by the pretreatment piping means enters the visualization cavity 24 through the gas piping. The gas line of the pretreatment line system is connected to a visualization chamber 24, which is provided with urineThe plain nozzle mounting seat can adjust the injection angle and pressure of the urea nozzle according to different research working conditions. The heat exchanger 23 is connected to the urea nozzle 22, and if the nozzle temperature is too high, the control unit controls the heat exchanger to cool down the nozzle. The urea nozzle 22 is externally connected with an outlet of a urea pump 25, an inlet of the urea solution supply pump is connected with a urea solution tank, and a pressure gauge II 27 is arranged at the outlet of the urea pump 25; the urea aqueous solution is sprayed into the visualization cavity 24 through the urea nozzle 2 by the urea pump 25 through the urea tank 26 to be mixed with the gas. The system adopts a visual device to observe the atomization effect of urea, so as to optimize the urea nozzle, avoid or reduce the formation of crystal sediment, and improve NO X The purpose of the conversion efficiency.
The detection system comprises an SCR mixer 28, an SCR catalyst 29 and NH 3 Sensor I30, NH3 sensor II 31, NO sensor II 32, NO 2 Sensor II 33, tail gas recovery tank 34 and pressure gauge III 35; the visualization cavity 24 is sequentially connected with an SCR mixer 28 and an SCR catalyst 29, and an exhaust gas recovery tank 34 is connected behind the SCR catalyst 29; an NH3 sensor I30 is arranged between the SCR mixer 28 and the SCR catalyst 29, and NH is arranged between the SCR catalyst 29 and the tail gas recovery tank 34 3 Sensor ii 31, NO sensor ii 32, NO2 sensor ii 33.
The simulated tail gas and urea solution are mixed by an SCR mixer and then enter a main place where gas reacts, namely an SCR catalyst, an NH3 sensor I is arranged at the front end of the catalyst, and an NH3 sensor II, an NO sensor II and an NO2 sensor II are arranged at the rear end of the catalyst to detect the conversion efficiency of NOx and the quantity of NH3 participating in the reaction. And finally, a tail gas recovery tank is arranged in the system to recover the reacted product, so that the pollution to the atmosphere is avoided.
NO sensor I32, NO 2 Sensor I15, flowmeter 17, electric heater 18, thermocouple 20, temperature control flange 21, heat exchanger 23, NH 3 Sensor I30, NH 3 Sensor II 31, NO sensor II 32, NO 2 The sensor II 33, the pressure gauge I16, the pressure gauge II 27 and the pressure gauge III 35 are all electrically connected with the control unit.
The data collected by the sensor is transmitted to the control unit, the control unit is utilized to analyze the data collected by the sensor, the conversion efficiency of the SCR system is calculated, the flow and the temperature of the gas in the pipeline can be measured, the characteristic parameters of the gas are obtained, the control is convenient, and the conversion efficiency of NOx can be measured under different flow and different temperatures in the test.
Considering the corrosiveness of urea aqueous solution, low carbon steel parts are easy to erode at high temperature, and the platform is made of SUS304 stainless steel.
A working method of an SCR urea aqueous solution spray visualization device for simulating a real exhaust environment,
operating a gas distribution supply system, controlling the opening of a valve of a gas storage tank by a control unit 1 according to the proportion of NOx in the actual engine operating condition, inputting gas into a surge tank 5 for mixing, thereby obtaining proper pseudo-tail gas, and taking the concentration of the NOx at the moment as an initial concentration;
the simulated tail gas is sent into a pretreatment pipeline system, the flow of the mixed gas is measured in advance by a flowmeter 17 before the mixed gas flows through an electric heater 18, then the temperature is measured by a thermocouple 20, and the mixed gas is converted into an electric signal to be input into a control unit 1 when flowing through a temperature control flange 21, so that the resistance power is controlled, the air is kept at the required temperature, and the mixed gas is more approximate to the actual tail gas emission environment working condition of an engine;
the obtained gas is sent into a urea injection system, fully mixed with urea solution sprayed by a urea nozzle 22 and then enters an SCR catalyst 29, and catalytic reaction is carried out inside the SCR catalyst to convert NOx into N 2 And H 2 O. Meanwhile, the atomization effect of the urea solution at the nozzle can be observed through the visual cavity 24 in the spraying system, so that the urea nozzle 22 is convenient to optimally adjust, urea crystallization is avoided, and the conversion efficiency is improved;
the tail gas after reaction finally enters a detection system and passes through a NH3 sensor II 31, a NO sensor II 32 and NO 2 The sensor II 33 obtains the final concentration of pollutants in the treated tail gas, and the conversion efficiency of the system and the utilization rate of urea can be obtained by comparing the initial concentration obtained previously with the final concentration at the moment;
the products after the reaction are recovered in the tail gas recovery tank 34 to avoid polluting the atmosphere. If the pressure in the tail gas recovery tank 34 is too high, timely air leakage treatment is carried out;
considering the corrosiveness of urea aqueous solution, the present patent is made of SUS304 stainless steel.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations may be made in the above embodiments by those skilled in the art without departing from the spirit and principles of the invention.
Claims (10)
1. The SCR urea aqueous solution spray visualization device for the simulated real exhaust environment is characterized by comprising a gas distribution supply system, a pretreatment pipeline system, a urea injection system and a detection system; the gas distribution supply system, the pretreatment pipeline system, the urea injection system and the detection system are sequentially connected; the gas distribution supply system is used for providing the simulated tail gas meeting the requirements; the pretreatment pipeline system heats the simulated exhaust to enable the simulated exhaust to have the same exhaust emission temperature as the actual engine exhaust emission temperature; the urea injection system injects urea solution into the tail gas to be treated by the pretreatment pipeline system and then catalyzes the tail gas to convert NOx into N 2 And H 2 O; the detection system is used for detecting the concentration of pollutants in the tail gas treated by the urea injection system.
2. According to claim 1The SCR urea aqueous solution spray visualization device of the pseudo-real exhaust environment is characterized in that the gas distribution supply system comprises an NO bottle (2) and NO 2 A bottle (3), an air bottle (4) and a surge tank (5); the NO bottle (2) and NO 2 The bottle (3) and the air bottle (4) are communicated with the surge tank (5) through pipelines, and the mixed gas is treated by the surge tank (5); the surge tank (5) is provided with a NO sensor I (14) and NO 2 The device comprises a sensor I (15) and a pressure gauge I (16), wherein a valve IV (12) and a one-way valve IV (13) are further arranged on a pipeline, communicated with the pretreatment pipeline system, of the surge tank (5).
3. The SCR aqueous urea solution spray visualization device of a quasi-real exhaust environment according to claim 1, characterized in that the pre-treatment piping system comprises a flow meter (17), an electric heater (18), a thermocouple (20) and a temperature control flange (21); the mixed gas of the gas distribution supply system enters a gas transmission pipeline in the pretreatment pipeline system, a flowmeter (17), an electric heater (18), a thermocouple (20) and a temperature control flange (21) are sequentially arranged on the gas transmission pipeline, and an electric heating wire (19) is arranged in the electric heater (18).
4. The SCR aqueous urea solution spray visualization device of a quasi-real exhaust environment according to claim 1, characterized in that the urea injection system comprises a urea nozzle (22), a heat exchanger (23) and a visualization cavity (24); the main pipeline of the pretreatment pipeline system is connected with a visualization cavity (24), a urea nozzle (22) is arranged in the visualization cavity (24), a heat exchanger (23) is connected with the urea nozzle (22), the urea nozzle (22) is externally connected with an outlet of a urea pump (25), and an inlet of the urea pump (25) is connected with a urea tank (26).
5. The SCR aqueous urea solution spray visualization device for a quasi-real exhaust environment according to claim 1, characterized in that the detection system comprises an SCR mixer (28), an SCR catalyst (29), NH 3 Sensor I (30), NH 3 Sensor II (31), NO sensor II (32), NO 2 A sensor II (33), an exhaust gas recovery tank (34) and a pressure gauge III (35);the visual cavity (24) is sequentially connected with an SCR mixer (28) and an SCR catalyst (29), an exhaust gas recovery tank (34) is connected behind the SCR catalyst (29), and a pressure gauge III (35) is arranged in the exhaust gas recovery tank; an NH3 sensor I (30) is arranged between the SCR mixer (28) and the SCR catalyst (29), and an NH3 sensor II (31), an NO sensor II (32) and an NO are arranged between the SCR catalyst (28) and the tail gas recovery tank (34) 2 Sensor II (33).
6. The SCR urea aqueous solution spray visualization device for the pseudo-real exhaust environment according to claim 2, wherein a valve I (6) and a one-way valve I (7) are arranged on a connecting pipeline of the NO bottle (2) and the surge tank (5); the NO 2 The connecting pipeline of the bottle (3) and the pressure stabilizing tank (5) is provided with a valve II (8) and a one-way valve II (9); the connecting pipeline of the air bottle (4) and the pressure stabilizing tank (5) is provided with a valve III (10) and a one-way valve III (11).
7. A SCR aqueous urea solution spray visualization apparatus according to claim 3, characterized in that the heat exchanger (23) is connected to a urea nozzle (22), the urea nozzle (22) changing the urea injection angle, the urea solution feed pump being provided with a pressure gauge ii (27).
8. The visual device for spraying SCR urea aqueous solution in a pseudo-real exhaust environment according to claim 4, wherein the inlet of said SCR mixer (28) is screwed with the visual cavity (24) by a union i (36), and the outlet of said SCR mixer (28) is screwed with the SCR catalyst (29) by a union ii (37); rubber gaskets are arranged in the movable joint I (36) and the movable joint II (37).
9. The SCR aqueous urea solution spray visualization apparatus for pseudo-real exhaust gas environment as recited in claim 5, wherein the NO sensor i (14), NO 2 Sensor I (15), flowmeter (17), electric heater (18), thermocouple (20), temperature control flange (21), heat exchanger (23), NH3 sensor I (30), NH 3 Sensor II (31), NO sensorSensor II (32), NO 2 The sensor II (33), the pressure gauge I (16), the pressure gauge II (27) and the pressure gauge III (35) are electrically connected with the control unit (1).
10. The method of operating an SCR aqueous urea solution spray visualization device for a quasi-real exhaust environment according to any one of claims 1-9, comprising the steps of:
the control unit (1) controls the NO bottle (2) and NO according to the proportion of the NOx in the actual engine operation condition 2 The opening of the valves of the bottle (3) and the air bottle (4) and the gas are input into the pressure stabilizing tank (5) for mixing, so that proper pseudo-tail gas is obtained, and the concentration of NOx at the moment is taken as the initial concentration;
the simulated tail gas is sent to a pretreatment pipeline system, the flow of the gas is measured in advance by a flowmeter (17) before the mixed gas flows through an electric heater (18), then the temperature is measured by a thermocouple (20), and the temperature data is converted into an electric signal when the mixed gas flows through a temperature control flange (21) to be input into a control unit (1), so that the resistance power is controlled, the air is kept at the required temperature, and the mixed gas is more similar to the actual tail gas emission environment working condition of an engine;
the obtained gas is sent into a urea injection system, fully mixed with urea solution sprayed by a urea nozzle (22) and then enters an SCR catalyst (29), and catalytic reaction is carried out inside the SCR catalyst to convert NOx into N 2 And H2O; meanwhile, the atomization condition of the urea solution at the nozzle can be observed through a visual cavity (24) in the spraying system so as to adjust the urea nozzle (22) to avoid urea crystallization;
the tail gas after reaction finally enters a detection system and passes through NH 3 Sensor II (31), NO sensor II (32) and NO 2 The final concentration of pollutants in the treated tail gas is obtained by a sensor II (33), and the conversion efficiency of the system and the utilization rate of urea can be obtained by comparing the initial concentration obtained previously with the final concentration at the moment;
the reacted product is recovered in a tail gas recovery tank (34) to avoid polluting the atmosphere.
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| CN116735183A (en) * | 2023-08-14 | 2023-09-12 | 烟台盈德精密机械有限公司 | Urea injection experimental device |
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| CN116735183A (en) * | 2023-08-14 | 2023-09-12 | 烟台盈德精密机械有限公司 | Urea injection experimental device |
| CN116735183B (en) * | 2023-08-14 | 2023-11-03 | 烟台盈德精密机械有限公司 | Urea injection experimental device |
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