CN103291419B - A kind of tail gas purification device of combustion engine - Google Patents

Abstract

The invention discloses a device for purifying exhaust gas of an internal combustion engine, which comprises a gaseous ammonia generating system, a particle removal system and a catalytic reaction system connected in sequence; The urea solution is sprayed into a very fine mist, and gaseous ammonia is generated under the action of high-temperature exhaust gas; the front end of the particle removal system is connected to the gaseous ammonia generation system, and the rear end is connected to the catalytic reaction system to remove solid particles in the exhaust gas of the internal combustion engine by filtering ; The catalytic reaction system is provided with a catalyst carrier on which the catalyst required for the reduction reaction is coated. The device of the invention is simple in structure, small in size and light in weight. It only needs a set of exquisite airflow spray device or high-pressure spray device to realize the function of gaseous ammonia generation, and has strong practicability; it fundamentally solves the safety of the selective catalytic reduction method It solves the problem of unstable gaseous ammonia production in the selective catalytic reduction method.

Description

A device for purifying exhaust gas of an internal combustion engine

technical field

The invention relates to the technical field of environmental protection, in particular to an exhaust gas purification device of an internal combustion engine.

Background technique

For the exhaust emission pollution of internal combustion engines, the diesel engine is taken as an example. The exhaust gas emitted by diesel engines contains gaseous and solid pollutants. The gaseous pollutants are mainly NO _X , SO ₂ , CO, HC, oxides, and organic nitrogen compounds. and sulfur-containing mixtures, etc.; the most important solid pollutants are carbonized particles. Among the above-mentioned pollutants, the most important ones are _NOx , _CO , SO2, HC and solid particles (pm). In the prior art, the method for purifying the above-mentioned gaseous pollutants mainly adopts Selective Catalytic Reduction (SCR) to purify NO _X and CO in the gaseous pollutants; when using this method, the reactant is gaseous ammonia (NH3 ). The method for obtaining gaseous ammonia is to adopt ammonia water at normal temperature (because there is sensitivity between the amount of ammonia gas generation and the temperature, it is required to control the temperature range very narrowly, the high temperature ammonia gas is excessive, causing ammonia pollution, and the low temperature reactant amount is few. Low purification efficiency) naturally evaporates into ammonia. This set of gaseous ammonia generating devices includes ammonia evaporator, ammonia buffer tank, gas flow valve, etc. Compared with diesel engines, these devices are too bulky. At the same time, ammonia is a An explosive gas, if the concentration of ammonia in the air is within the range of 5% to 15%, it will explode with great destructive power and danger when it encounters an open flame, and the diesel engine exhaust is in a high temperature state. Therefore, It is unrealistic and dangerous to use ammonia evaporator, ammonia buffer tank, etc. to obtain gaseous ammonia in diesel engine exhaust purification equipment.

Contents of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is how to safely and efficiently process the tail gas discharged from the internal combustion engine in time, so as to avoid pollution from being discharged into the air.

(2) Technical solutions

In order to solve the above technical problems, the present invention provides an internal combustion engine tail gas purification device, which includes a gaseous ammonia generation system, a particle removal system and a catalytic reaction system connected in sequence; the front end of the gaseous ammonia generation system is connected to the exhaust port of the internal combustion engine, and the rear end Connected with the particle removal system, the gaseous ammonia generation system sprays the urea solution into a very fine mist in the form of air flow or high-pressure spray, and generates gaseous ammonia under the action of high-temperature exhaust gas; the front end of the particle removal system is connected with the gaseous ammonia generation system The rear end is connected to the catalytic reaction system to remove solid particles in the exhaust gas of the internal combustion engine by filtering; the catalytic reaction system is provided with a catalyst carrier, and the catalyst required for the reduction reaction is coated on the inner wall.

Wherein, it includes a front box body, a middle box body and a rear box body which are connected and connected in sequence, a gaseous ammonia generation system is set in the front box body, a particle removal system is set in the middle box body, and a catalytic reaction system is set in the rear box body. system.

Wherein, the gaseous ammonia generation system includes an airflow nozzle arranged in the front box, and a urea-water solution pipe and a compressed air supply pipe respectively connected to the interface of the airflow nozzle, and the urea-water solution pipe is connected with the urea The urea-water solution storage tank of the aqueous solution is connected, and the compressed air supply pipe is connected with external compressed air; the urea-water solution pipe and the compressed air supply pipe are respectively provided with a solution flow control valve and a compressed air control valve.

Wherein, the gaseous ammonia generation system includes a pressure spray nozzle arranged in the front box, and a urea-water solution pipe connected to the interface of the pressure spray nozzle, a solution flow control valve, a high-pressure gear pump and a urea-water solution in full bloom. Urea-water storage tank for aqueous solution.

Wherein, the front end of the middle box is connected to the front box, the rear end is connected to the rear box, the bottom end is connected to a tapered ash hopper, and an ash lock nut is installed at the bottom of the ash hopper; the rear end of the middle box is also connected to a blowing pipe. The blowing pipe is connected with the external compressed air.

Wherein, the blowing pipe is connected to the compressed air supply pipe through the compressed air branch pipe; the compressed air branch pipe is provided with a blowing air supply valve, a compressed air storage tank and an electromagnetic pulse valve in sequence, and the electromagnetic pulse valve The injection air supply valve controls the amount of compressed air entering the compressed air storage tank through the control wire. Blow gas into the middle box.

Wherein, the rear end of the middle box is provided with a blowing nozzle, and the blowing nozzle is connected with the blowing pipe.

Wherein, a filter cartridge flower plate is arranged in the middle box, the center of the filter cartridge flower plate is a circular hole, and the shape of the outer edge matches the cross-sectional shape of the inner cavity of the middle box; the filter cartridge flower plate is installed with The filter cartridge filter unit, the filter cartridge filter unit includes a filter cartridge front blind plate installed at the front end of the middle box, a filter cartridge ring plate installed at the rear end of the middle box, forming a columnar shape with the filter cartridge front blind plate and the filter cartridge ring plate The stainless steel filter felt in the cavity, and the filter cartridge inner protection net and filter cartridge outer protection net respectively arranged on the inner and outer walls of the stainless steel filter felt.

Wherein, the middle part of the rear box is provided with a cross-shaped partition, which divides the section of the rear box into four equal-sized spaces, and a ceramic catalytic unit is arranged in each equal-sized space.

Wherein, the ceramic catalytic unit is a ceramic catalyst carrier with a plurality of square channels opened along its longitudinal direction, and the inner wall of the square channel is coated with catalyst. Each ceramic catalytic unit is surrounded by a glass fiber shockproof felt to prevent ceramic Catalytic unit damaged by vibrations.

Wherein, a rear baffle is installed at the rear end of the rear box, and four holes corresponding to the positions of the ceramic catalytic unit and smaller in size than the ceramic catalytic unit are arranged on the rear baffle to prevent the ceramic catalytic unit from moving.

(3) Beneficial effects

The internal combustion engine tail gas purification device provided by the above technical solution has a simple structure, small size, and light weight. It only needs a set of exquisite airflow spray system or pressure spray system to realize the function of gaseous ammonia generation, and has strong practicability; it fundamentally solves the problem of The safety problem of the selective catalytic reduction method; the disadvantage of unstable gaseous ammonia production in the selective catalytic reduction method is solved.

Description of drawings

Fig. 1 is the structural representation of the internal combustion engine tail gas cleaning device of embodiment 1 of the present invention;

Fig. 2 is A-A sectional view among Fig. 1;

Fig. 3 is the B-B sectional view among Fig. 1;

Fig. 4 is a schematic structural view of an exhaust gas purification device of an internal combustion engine according to Embodiment 2 of the present invention.

Among them, 1: ash lock nut; 2: ash hopper; 3: front middle box fixing bolt group; 4: stainless steel filter felt; 5: front blind plate of filter cartridge; 6: air flow nozzle; 7: diesel engine exhaust pipe; 8: Front box; 9: Urea-water solution pipe; 10: Solution flow control valve; 11: Urea-water solution; 12: Urea-water solution storage tank; 13: Compressed air control valve; 14: Compressed air supply pipe ;15: Compressed air branch pipe; 16: Injection air supply valve; 17: Compressed air storage tank; 18: Injection control instrument; 19: Electromagnetic pulse valve; 20: Control wire; 21: Middle box; 22: Injection pipe; 23: Filter cartridge outer protection net; 24: Filter cartridge inner protection net; 25: Injection nozzle; 26: Rear box; 27: Glass fiber shockproof felt; 28: Ceramic catalytic unit; 29: Cross partition Plate; 30: rear baffle; 31: final discharge port; 32: filter cartridge flower plate; 33: filter cartridge fixing bolt group; 34: middle and rear box fixing bolt group; 35: filter cartridge ring plate; 36: high pressure gear pump ; 37: pressure spray nozzle.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

The present invention provides a device for purifying exhaust gas from diesel engines. The device uses urea (CON ₂ H ₄ )-water solution to enter the interior of the exhaust gas purification device through pipelines, and sprays through airflow (Example 1) or high-pressure spray (Example 2). The urea-water solution is changed into a micro-droplet state and fully mixed with high-temperature exhaust gas. Under the action of high-temperature tail gas, the urea in the urea-water solution is rapidly heated to above 160°C and decomposed, producing ammonia (NH ₃ ) and biuret ( CONH), wherein part of the ammonia (NH ₃ ) is used as the reactant for removing SO ₂ , and the other part is used as the reactant for the selective catalytic reduction method. This method not only has a small size of the ammonia gas generating device, but also has high safety and The precise control of the amount of ammonia gas can be realized by controlling the input amount of liquid urea.

Example 1

As shown in Figure 1: the diesel engine exhaust purification device for high-speed diesel engines with a displacement of 9 liters and a maximum speed of 2500r/min, its basic dimensions are: length × width × height = 1300mm × 400mm × 400mm, the device’s The structure is shown in Figure 1, Figure 2 is the A-A sectional view of Figure 1, and Figure 3 is the B-B sectional view of Figure 1, which includes the ash locking nut 1, the ash bucket 2, the front middle box fixing bolt group 3, and the stainless steel filter felt 4 , filter cartridge front blind plate 5, air flow nozzle 6, diesel engine exhaust pipe 7, front box 8, urea-water solution pipe 9, solution flow control valve 10, urea-water solution 11, urea-water solution storage tank 12, compressed air Control valve 13, compressed air supply pipe 14, compressed air branch pipe 15, injection air supply valve 16, compressed air storage tank 17, injection control instrument 18, electromagnetic pulse valve 19, control wire 20, middle box 21, Injection pipe 22, filter cartridge outer protection net 23, filter cartridge inner protection net 24, injection nozzle 25, rear box 26, glass fiber shockproof felt 27, ceramic catalytic unit 28, cross partition 29, rear baffle 30 , final discharge port 31, filter cartridge flower plate 32, filter cartridge fixing bolt group 33, middle and rear box fixing bolt group 34, filter cartridge ring plate 35.

In the present embodiment, gaseous ammonia is formed by air flow nozzle 6, front box body 8, urea-water solution pipe 9, solution flow control valve 10, urea-water solution storage tank 12, compressed air supply pipe 14, and compressed air control valve 13. system, wherein the front box body 8 is a horizontally placed steel plate sheet metal box body, its front part is cylindrical, the middle part is a round and square transition box body, its rear part is a square box body, and its front end is connected to the exhaust pipe of the diesel engine. 7, its rear end is connected to the middle box body 21 through the front middle box fixing bolt group 3, and its front part is a cylindrical box body, and the upper part is inserted into the urea-water solution pipe 9 and the compressed air supply pipe 14 respectively. Connect to the corresponding interface of the airflow nozzle 6 located in the center of the cylindrical box body; the other end of the urea-water solution pipe 9 is connected to the bottom of the urea-water solution storage tank 12, and a solution flow control valve 10 is arranged in the middle of the urea-water solution pipe, and the urea-water solution The storage tank 12 is a vertical tank body, and a compressed air control valve 13 is arranged in the middle of the compressed air supply pipe 14;

It consists of ash lock nut 1, ash hopper 2, stainless steel filter felt 4, filter cartridge front blind plate 5, compressed air branch pipe 15, injection air supply valve 16, compressed air storage tank 17, injection control instrument 18, electromagnetic Pulse valve 19, control wire 20, middle box 21, injection pipe 22, filter cartridge outer protection net 23, filter cartridge inner protection net 24, injection nozzle 25, filter cartridge flower plate 32, filter cartridge fixing bolt group 33 1. The filter cartridge ring plate 35 forms a particle removal system. The middle box 21 is a square steel sheet metal box with the front and rear ends and the lower end vacant in a horizontal position. The thread on the outside of the lower cylinder of the steel plate ash hopper; the front end of the middle box 21 is connected to the front box 8 through the front middle box fixing bolt group 3, and its rear end is connected to the rear box through the middle and rear box fixing bolt group 34. 26 connection; a filter cartridge flower plate 32 made of an outer inner circular steel plate is arranged in its inner cavity, and the outer side of the filter cartridge flower plate 32 is welded to the rear part of the inner cavity of the middle box body 21; the front blind plate 5 of the filter cartridge Filter cartridge ring plate 35, filter cartridge outer protective net 23, filter cartridge inner protective net 24, and stainless steel filter felt 4 form a filter cartridge filter unit in which the filter material is stainless steel filter felt 4, and the front blind plate 5 of the filter cartridge is a steel plate Make a round blind plate, the filter cartridge ring plate 35 is a steel annular steel plate, and its inner circle is the air outlet channel for the outer filter cartridge, and the stainless steel filter felt 4 is a folded accordion box shape and surrounded into a cylindrical shape filter material, its outer layer is surrounded by a filter cartridge outer layer protection net 23, and its inner layer has a mesh filter cartridge inner layer protection net 24. This filter cartridge filter unit is connected on the filter cartridge flower plate 32 through the filter cartridge fixing bolt group 33 . A compressed air branch pipe 15 is connected from the compressed air supply pipe 14, and a blowing air supply valve 16 is set on the pipe to supply compressed air to the compressed air storage tank 17. When the amount of particulate matter exceeds a certain limit, the injection controller 18 sends a signal through the control wire 20 to energize the electromagnetic pulse valve 19, and the electromagnetic pulse valve 19 opens instantly, and the compressed air in the compressed air storage tank passes through the injection pipe 22 to the injection nozzle. 25 Blow to the inner cavity of the outer filter cartridge (opposite to the direction of exhaust gas filtration) to clean up the ash accumulated on the filter layer, and the cleaned ash will fall into the ash hopper. Gray nut 1 is discharged.

The catalytic reaction system is composed of a rear box 26, a glass fiber shockproof felt 27, a ceramic catalytic unit 28, a cross partition 29, a rear baffle 30, and a final discharge port 31. The rear box 26 is a square box and a front and back circle. The box body is combined, and its front end is connected with the middle box body through the fixing bolt group 34 of the middle and rear box body, and the rear end is welded with the final discharge port 31. A cross partition 29 is set in the middle part of the rear box body 26, and the square section of the rear box body 26 is divided into four square spaces of equal size. A ceramic catalytic unit 28 is built in each square space. The ceramic catalytic unit 28 is a Open the catalyst carrier of many square passages (cross-sectional size is 4.3mm * 4.3mm), on the inner wall of its square passage, coat the ceramic product of catalyst, adopt glass fiber antivibration blanket 27 to wrap around each ceramic catalytic unit 28, prevent ceramic The catalytic unit 28 is damaged in the event of shocks. The rear baffle 30 is a square steel plate, and four square holes slightly smaller than the ceramic catalytic unit are evenly distributed inside, so as to prevent the ceramic catalytic unit from moving forward.

Example 2

The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the air flow nozzle 6, the front box body 8, the urea-water solution supply pipe 9, the solution flow control valve 10, the urea-water solution storage tank 12, the compressor The gaseous ammonia generating system formed by the air supply pipe 14 and the compressed air control valve 13 is replaced by a high-pressure gear pump 36, a front casing 8, a pressure spray nozzle 37, a solution flow control valve 10, a urea-water solution pipe 9 and a urea- A gaseous ammonia generating system composed of aqueous solution storage tank 12; the spraying method is replaced by airflow spraying to pressure spraying; wherein the front box 8 is a horizontal steel sheet metal box, the front part is cylindrical, and the middle part is Round and square excessive box, its rear part is a square box, its front end is connected with the exhaust pipe 7 of the diesel engine, its rear end is connected with the middle box body 21 through the front middle box fixing bolt group 3, and its front part is cylindrical The upper part of the box body is inserted into the urea-water solution pipe 9 respectively, and the pipeline is connected to the corresponding interface of the pressure spray nozzle 37 located in the center of the cylindrical box body; the other end of the urea-water solution pipe 9 is connected to the solution flow control valve 10 and the high-pressure gear The pump 36 and the urea-water solution storage tank 12 are a vertical tank body.

Above-mentioned embodiment 1 and the working principle of the device gas that is used for internal combustion engine tail gas purification of embodiment 2 are the same, as follows:

When working normally, the urea-water solution 11 in the urea-water solution storage tank 12 in the embodiment 1 enters the air flow type nozzle 6 through the urea-water solution pipe 9 and the solution flow control valve 10 under the action of gravity; through the compressed air supply pipe 14 1. The compressed air of the compressed air control valve 13 also enters the airflow nozzle 6 at the same time. In the airflow nozzle 6, the compressed air is fully mixed with the urea-water solution 11. Under the action of the speed difference of 11, the liquid film of urea-water solution 11 is torn, forming very fine urea-water solution 11 droplets, which are sprayed out of the airflow nozzle 6, forming a mist area formed by very fine urea-water solution 11 droplets .

During normal operation, the urea-water solution 11 in the urea-water solution storage tank 12 in the embodiment 2 is supplied to the pressure spray nozzle 37 through the urea-water solution pipe 9 and the solution flow control valve 10 under the suction of the high-pressure gear pump 36. A high-pressure urea-water solution flow is provided, and the pressure spray nozzle 37 sprays out a mist area formed by extremely fine urea-water solution 11 droplets under the action of high pressure.

The diesel engine exhaust enters the front cylindrical box of the front box body 8 through the diesel engine exhaust pipe 7, and after encountering the mist area formed by the extremely fine urea-water solution 11 droplets, it mixes rapidly, because the diesel engine exhaust is a high-temperature gas (350 ℃--430℃), so the extremely fine urea-water solution 11 droplets are heated rapidly, the water in it evaporates rapidly, and the urea (CON ₂ H ₄ ) in it will decompose at high temperature (above 160℃) (CON ₂ H ₄ )=(NH ₃ )+(CONH), producing ammonia gas (NH ₃ ) and biuret (CONH), wherein the ammonia gas is mixed with the gas in the tail gas, and a part of the ammonia gas is immediately mixed with the gas in the tail gas Sulfur dioxide undergoes the following chemical reaction, and its reaction formula is:

SO ₂ +H ₂ O+xNH ₃ =(HN ₄ )xH ₂ −xSO ₃ (1)

Obtain ammonium sulfite intermediate product, and ammonium sulfite is further oxidized:

(NH ₄ )XH ₂ -XSO ₃ +1/2O ₂ +(2-x)NH ₃ ＝(NH ₄ )2SO ₄ 2

Complete dry desulfurization is achieved, and the final products after desulfurization, ammonium sulfate (NH ₄ ) ₂ SO ₄ and biuret (CONH) after urea decomposition, will form fine solid particles and mix into the tail gas.

The main part contained in the middle box 21 is the particle removal system, which is actually a pleated filter cartridge with stainless steel filter felt 4 as the filter material. The mixed gas of tail gas and residual ammonia after desulfurization enters the middle box from the front box 8 21 After the front end, it first encounters the front blind plate 5 of the filter cartridge, which is a round blind plate made of steel plate, and the mixed gas cannot pass through, so it can only bypass the outer layer of the folded stainless steel filter felt 4, and then pass through the folded stainless steel filter felt 4 Enter the inner cavity of the filter cartridge to achieve filtration. Through filtration, the particulate matter in the exhaust gas (including the original carbonized particulate matter in the exhaust gas and fine solid particles of biuret (CONH) after urea decomposition and ammonium sulfate (NH ₄ ) ₂ SO ₄ after desulfurization) is removed. When the stainless steel filter felt 4 accumulates a certain amount of particles, the resistance of the filter layer will increase, affecting the passage of the mixed gas. At this time, by starting the injection control device 18, a signal is sent through the control wire 20 to energize the electromagnetic pulse valve 19. The electromagnetic pulse valve 19 is opened instantly, the compressed air in the compressed air storage tank 17 passes through the injection pipes 22 and 22 to the injection nozzle 25, and the injection nozzle 25 sprays to the inner cavity of the outer filter cartridge (opposite to the exhaust gas filtration direction) , to realize cleaning the accumulated particles attached to the stainless steel filter felt 4 outer layers, the cleaned particles fall into the ash hopper 2, and after the ash hopper 2 is full of particles, unscrew the ash lock nut 1 to discharge. The mixed gas of the exhaust gas after filtering to remove particulate matter and the residual ammonia after desulfurization enters the catalytic reaction system in the rear box 26 through the hollow channel of the filter cartridge flower plate 32 and the filter cartridge ring plate 35, and the mixed gas passes through the ceramic catalytic unit When the multiple inner walls of 28 are coated with catalyst square channels, under high temperature and catalytic conditions, the gaseous ammonia in the exhaust gas mixture and nitrogen oxides (including NO and NO ₂ ) undergo the following chemical reactions:

4NH ₃ +4NO+O ₂ ＝4N ₂ +6H ₂ O

8NH ₃ +6NO ₂ ＝7N ₂ +12H ₂ O2

At the same time, under high temperature and catalytic conditions, carbon monoxide and nitrogen oxides (including NO and NO ₂ ) in the exhaust gas mixture undergo the following chemical reactions:

2CO+2NO+O ₂ ＝2CO ₂ +N ₂

4CO+2NO ₂ ＝4CO ₂ +N ₂ 2

Through the above chemical reaction, the carbon monoxide and nitrogen oxides in the exhaust gas of the diesel engine are converted into nitrogen, carbon dioxide and water which are harmless to the environment. To sum up, through the above three-stage purification, the main gaseous pollutants (NO _X , SO ₂ , CO) and solid particle pollutants emitted by diesel engines are eliminated. Achieve the vast majority of removal. Therefore, the above structure and process bring the following beneficial effects:

(1) The device is simple in structure, small in size and light in weight, and only needs a set of exquisite airflow spraying system to realize the function of gaseous ammonia generation, replacing the ammonia evaporator, ammonia buffer tank, gas flow valve, etc. in the selective catalytic reduction method The gaseous ammonia generation system composed of huge equipment is more practical for most diesel engines that are mobile pollution sources.

(2) Fundamentally solve the safety problem of selective catalytic reduction method

Because the selective catalytic reduction method is to produce gaseous ammonia by evaporating ammonia water in the ammonia evaporator, and finally mix the gaseous ammonia into the tail gas through the ammonia buffer tank. In this process, the concentration of gaseous ammonia can easily reach the explosion criticality. interval concentration, there is a very high potential safety hazard; and the method for producing gaseous ammonia in the present invention is to directly mix urea-water solution into the high-temperature tail gas, and generate gaseous ammonia through the decomposition of urea, and the concentration of gaseous ammonia generated by this method can be far It is far away from the concentration explosion range of ammonia, thus completely eliminating the safety hazard of the selective catalytic reduction method.

(3) Solve the disadvantages of unstable gaseous ammonia production in the selective catalytic reduction method

Since the selective catalytic reduction method regenerates gaseous ammonia in the ammonia evaporator, its production is very sensitive to temperature, and the temperature of the ammonia evaporator must be precisely controlled to control the production. At the same time, it must be buffered by the ammonia buffer tank. Then use the gas regulating valve to adjust, and finally realize the injection of an appropriate amount of ammonia into the exhaust gas. And the present invention is different because of the method for generating gaseous ammonia, and the injection amount of its gaseous ammonia in tail gas completely depends on the concentration and the injection amount of urea-water solution, and concentration is very easy to control when disposing, as long as the mixing amount passes through a liquid regulating valve ( Much smaller than a gas regulating valve) can be precisely controlled and will not change due to changes in temperature conditions. Therefore, the purpose of precisely controlling the injection of tail gas gaseous ammonia is realized. It will not cause ammonia pollution due to excessive injection of gaseous ammonia, and will not cause low efficiency of purifying _NOx and CO in gaseous pollutants due to too little injection of gaseous ammonia.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (8)

1. An internal combustion engine tail gas purification device is characterized in that it comprises a gaseous ammonia generation system, a particle removal system and a catalytic reaction system connected in sequence; the front end of the gaseous ammonia generation system is connected to the exhaust outlet of the internal combustion engine, and the rear end is connected to the particle removal The gaseous ammonia generation system sprays the urea solution into a very fine mist in the form of airflow or high-pressure spray, and generates gaseous ammonia under the action of high-temperature exhaust gas; the front end of the particle removal system is connected to the gaseous ammonia generation system, and the rear The end is connected with the catalytic reaction system to remove solid particles in the exhaust gas of the internal combustion engine by filtering; the catalytic reaction system is provided with a catalyst carrier, and the catalyst required for the reduction reaction is coated on the inner wall; The internal combustion engine exhaust gas purification device includes a front box, a middle box and a rear box connected in sequence, a gaseous ammonia generation system is arranged in the front box, a particle removal system is arranged in the middle box, and a particulate matter removal system is arranged in the rear box. A catalytic reaction system is installed in the box; The middle part of the rear box is provided with a cross-shaped partition, which divides the section of the rear box into four equal-sized spaces, and a ceramic catalytic unit is arranged in each equal-sized space; The ceramic catalytic unit is a ceramic catalyst carrier with a plurality of square passages along its longitudinal direction and a catalyst coated on the inner wall of the square passage. Each ceramic catalytic unit is surrounded by a glass fiber shockproof felt to prevent the ceramic catalytic unit from Damaged in case of shock. 2. internal-combustion engine tail gas purification device as claimed in claim 1, is characterized in that, described gaseous ammonia generating system comprises the air-flow type shower head that is arranged in front casing, and the urea-water solution pipe that links to each other with the interface of air-flow type shower head and Compressed air supply pipe, the urea-water solution pipe is connected with the urea-water solution storage tank filled with urea-water solution, and the compressed air supply pipe is connected with external compressed air; on the urea-water solution pipe and the compressed air supply pipe A solution flow control valve and a compressed air control valve are respectively provided. 3. The internal combustion engine tail gas purification device according to claim 1, wherein the gaseous ammonia generating system comprises a pressure spray nozzle arranged in the front casing, and a urea-water solution that is connected to the interface of the pressure spray nozzle respectively Pipe, solution flow control valve, high-pressure gear pump and urea-water solution storage tank filled with urea-water solution. 4. The internal combustion engine exhaust gas purification device according to claim 2, wherein the front end of the middle box is connected to the front box, the rear end is connected to the rear box, the bottom end is connected to a conical ash hopper, and the bottom of the ash hopper is installed to lock the ash Nut; the rear end of the middle box is also connected with a blowing pipe, and the blowing pipe is connected with the external compressed air. 5. The internal combustion engine exhaust gas purification device according to claim 4, wherein the blowing pipe is connected to the compressed air supply pipe through a compressed air branch pipe; Valve, compressed air storage tank and electromagnetic pulse valve. The electromagnetic pulse valve is connected to the injection controller through the control wire. The injection air supply valve controls the amount of compressed air entering the compressed air storage tank. The electromagnetic pulse valve sends an energization signal to control the opening of the electromagnetic pulse valve to blow gas into the middle box through the blowing pipe. 6 . The exhaust gas purification device of an internal combustion engine according to claim 5 , wherein a blowing nozzle is arranged at the rear end of the middle box, and the blowing nozzle is connected with the blowing pipe. 7 . 7. The exhaust gas purification device of an internal combustion engine according to claim 1, wherein a filter cartridge flower plate is arranged in the middle box, the center of the filter cartridge flower plate is a circular hole, and the shape of the outer edge is the same as that in the middle box. The cross-sectional shape of the cavity matches; the filter cartridge filter unit is installed on the flower plate of the filter cartridge, and the filter cartridge filter unit includes the front blind plate of the filter cartridge installed at the front end of the middle box, and the filter cartridge installed at the rear end of the middle box. The ring plate, the stainless steel filter felt forming a columnar cavity with the filter cartridge front blind plate and the filter cartridge ring plate, and the filter cartridge inner protection net and filter cartridge outer protection net respectively arranged on the inner and outer walls of the stainless steel filter felt. 8. The device for purifying exhaust gas of an internal combustion engine according to claim 1, wherein a rear baffle is installed at the rear end of the rear box body, and four ceramic catalyst units are arranged on the rear baffle and have a size corresponding to the position of the ceramic catalytic unit. The holes are smaller than the ceramic catalytic unit to prevent the ceramic catalytic unit from moving.