CN201120254Y

CN201120254Y - SCR catalytic converter

Info

Publication number: CN201120254Y
Application number: CNU2007200761224U
Authority: CN
Inventors: 单小丰; 李兵; 张宝龙; 沈峰
Original assignee: SHANGHAI HUAKE EXHAUST AIR SYSTEM CO Ltd
Current assignee: SHANGHAI HUAKE EXHAUST AIR SYSTEM CO Ltd
Priority date: 2007-11-13
Filing date: 2007-11-13
Publication date: 2008-09-24
Anticipated expiration: 2017-11-13

Abstract

An SCR catalytic converter comprises a shell, an upper buffer plate, a lower buffer plate, an air inlet pipe, an air outlet pipe and carrier components, wherein the upper buffer plate and the lower buffer plate are arranged in interval in the shell and divide the cavity of the shell into an upper buffer cavity, a middle cavity and a lower buffer cavity, wherein a plurality of punch holes are arranged on the upper buffer plate to communicate the upper buffer cavity and the middle cavity, the lower buffer plate separates the middle buffer cavity and the lower buffer cavity, the air inlet pipe is inserted into the shell from the upper end surface of the shell and is communicated with the lower buffer cavity after passing through the upper buffer plate and the middle buffer plate, the air outlet pipe is inserted into the shell from the upper end surface of the shell and is sealedly connected with the lower buffer plate after passing through the upper buffer plate, the lower portion of the air outlet pipe is provided with a plurality of air cavities and is communicated with the middle cavity, and the carrier components are all arranged side by side in multiple-group between the upper buffer plate and the lower buffer plate and are respectively communicated with the upper and the lower buffer cavities. The SCR catalytic converter of the utility model has good flow performance, proper pressing damage rate and the function of noise elimination.

Description

The SCR catalytic converter

Technical field

The utility model relates to a kind of diesel engine vent gas treatment facility, particularly a kind of SCR catalytic converter.

Background technology

Diesel engine is having remarkable advantages than gasoline engine aspect dynamic property, economy and the reliability, and particularly the CO2 discharging is very low, and its purposes expands on all kinds of vehicles gradually.But it is that nitrogen oxide and particulate emission are serious that there is maximum problem in diesel engine.Along with Chinese emission control regulations are more and more tighter, and homemade Diesel engine performance and oil product problem, depend the emission controls by improving combustion measure alone and seem unable to do what one wishes, therefore be necessary to take the outer after-treatment system of machine to reach emissions object.

The SCR technology is the outer post-processing technology of a kind of machine of vehicle diesel engine, can effectively improve the discharging of diesel engine nitrogen oxide, and insensitive to the diesel oil sulfur content.This technology is by spraying into certain density urea liquid in blast pipe, reduction reaction (reaction 3-5) takes place in ammonia that produces after pyrolysis (reaction 1) and hydrolysis (reaction 2) and nitrogen oxide in catalytic converter, be steam and nitrogen (reaction 3-5 needs could effectively carry out at a certain temperature) with conversion of nitrogen oxides.

(NH ₂) ²CO→NH ₃+HNCO (1)

NH ₃+HNCO→NH ₃+CO ₂ (2)

4NO+4NH ₃+O ₂→4N ₂+6H ₂O (3)

2NH ₃+NO+NO ₂→2N ₂+3H ₂O (4)

6NO ₂+8NH ₃→7N ₂+12H ₂O (5)

For the main performance of SCR catalytic converter, can assess by following index.

1, the distribution of fluid between each carrier and the flow uniformity value of each carrier front end face

Improve the mass flow distribution of waste gas between each carrier, help improving the utilization rate of carried catalyst; Help reducing the pressure loss of air-flow on carrier; Help carrier and reach initiation temperature faster.

2, the pressure loss of system

The pressure loss of catalytic converter is a part of whole gas extraction system crushing, and the pressure loss that reduces catalytic converter helps reducing the back pressure of gas extraction system, thereby helps improving the performance of engine.

3, air speed

The size of air speed has been reacted the time of staying of air-flow in carrier.Air speed is more little, and the time of staying of air-flow in carrier is long more, helps reducing the reduction reaction of nitrogen oxide more.

4, acoustic insertion loss.

The utility model content

The purpose of this utility model is to provide a kind of good flowing properties, the moderate SCR catalytic converter of crushing.

The purpose of this utility model is achieved in that a kind of SCR catalytic converter, comprises housing, overhead gage, lower baffle plate, gas inlet pipe, gas outlet tube and carrier module; Overhead gage and lower baffle plate are disposed in the housing and the housing inner chamber are separated into cushion chamber, lumen and following cushion chamber, and overhead gage wherein is provided with a plurality of perforation and will goes up cushion chamber and be communicated with lumen, and lower baffle plate is with lumen and the separation of following cushion chamber; Gas inlet pipe is inserted in the housing from the upper surface of housing and is passed overhead gage and lower baffle plate is communicated with following cushion chamber; Gas outlet tube inserts in the housing from the upper surface of housing and passes overhead gage and links to each other with the lower baffle plate sealing, and the bottom of gas outlet tube is provided with a plurality of pores and is communicated with lumen; The many altogether groups of carrier module are arranged side by side between overhead gage and lower baffle plate and are communicated with upper and lower cushion chamber respectively.

Described carrier module comprises carrier, and this carrier is cylindrical ceramic goods, and it is axially arranged with many parallel channels and connects both ends of the surface, is provided with catalyst coat at the inner surface of each passage.

Described catalyst is that zeolite based catalysts or scherbinaite are catalyst based.

Described carrier module also comprises the liner housing outer with being coated on liner that is coated on outside the carrier.

Described carrier module totally 4 groups be distributed in gas inlet pipe around.

SCR catalytic converter of the present utility model is hydrodynamics (CFD) flow analysis and acoustic analysis demonstration as calculated, shows that it has good flowing properties, moderate advantage and the characteristics of crushing, and has the effect of silencer.The design of cushion chamber, perforation overhead gage and perforation gas outlet tube can guarantee that air-flow pressure loss when flowing through catalytic converter is moderate up and down; Housing in the carrier module and liner can be protected and holding carrier, prevent carrier broken inefficacy in vehicle travels; Cushion chamber up and down, the design of perforation overhead gage and perforation gas outlet tube also makes catalytic converter have the noise elimination effect of silencer.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the utility model SCR catalytic converter;

Fig. 2 is the structural representation of the carrier module in the utility model.

The specific embodiment

Referring to Fig. 1, SCR catalytic converter of the present utility model comprises housing 1, overhead gage 2, lower baffle plate 3, gas inlet pipe 4, gas outlet tube 5 and carrier module 6.Overhead gage 2 and lower baffle plate 3 are disposed in the housing 1 and with the space in the housing and are separated into cushion chamber 7, lumen 8 and following cushion chamber 9, overhead gage wherein is provided with a plurality of perforation and will goes up cushion chamber and be communicated with lumen, lower baffle plate is lumen and the separation of following cushion chamber, can prevent that exhaust before and after treatment from ganging up mutually.Gas inlet pipe 4 is inserted in the housing from the upper surface of housing 1 and is passed overhead gage 2 and lower baffle plate 3 is communicated with following cushion chamber 9; Gas outlet tube 5 inserts in the housing from the upper surface of housing and passes overhead gage 2 and links to each other with lower baffle plate 3 sealings, and the bottom of gas outlet tube 5 is provided with a plurality of pores 51 and is communicated with lumen; Carrier module totally 4 groups be distributed in gas inlet pipe 4 around, be arranged side by side between overhead gage 2 and lower baffle plate 3 and be communicated with upper and lower cushion chamber respectively.

Referring to Fig. 2, the carrier module 6 in the utility model comprises carrier 61, is coated on the outer liner 62 of carrier and is coated on the outer housing 63 of liner.Carrier 61 is cylindrical ceramic goods, and it is axially arranged with many parallel channels 611 and connects both ends of the surface, is provided with catalyst coat at the inner surface of each passage.Can be catalyst based as the catalyst of catalyst coat for zeolite based catalysts or scherbinaite.Housing and liner can be protected and holding carrier, prevent carrier broken inefficacy in vehicle travels.

The operation principle of the utility model SCR catalytic converter can be described as follows in conjunction with Fig. 1:

Diesel engine exhaust enters down cushion chamber 9 by gas inlet pipe 4, and air-flow is diverted in four carrier modules 6 after reorganizing, and its each composition chemical reaction takes place to reduce nitrogen oxide at this.Air-flow enters cushion chamber 7 after carrier module 6 is handled, the perforation on last plate washer 5 enters lumen 8 again, enters gas outlet tube 5 from the pore that is arranged on gas outlet tube 5 bottoms at last, discharges from tail pipe by gas outlet tube 5 again.

Claims

1, a kind of SCR catalytic converter is characterized in that: comprise housing, overhead gage, lower baffle plate, gas inlet pipe, gas outlet tube and carrier module; Overhead gage and lower baffle plate are disposed in the housing and the housing inner chamber are separated into cushion chamber, lumen and following cushion chamber, and overhead gage wherein is provided with a plurality of perforation and will goes up cushion chamber and be communicated with lumen, and lower baffle plate is with lumen and the separation of following cushion chamber; Gas inlet pipe is inserted in the housing from the upper surface of housing and is passed overhead gage and lower baffle plate is communicated with following cushion chamber; Gas outlet tube inserts in the housing from the upper surface of housing and passes overhead gage and links to each other with the lower baffle plate sealing, and the bottom of gas outlet tube is provided with a plurality of pores and is communicated with lumen; The many altogether groups of carrier module are arranged side by side between overhead gage and lower baffle plate and are communicated with upper and lower cushion chamber respectively.

2, SCR catalytic converter according to claim 1, it is characterized in that: described carrier module comprises carrier, this carrier is cylindrical ceramic goods, and it is axially arranged with many parallel channels and connects both ends of the surface, is provided with catalyst coat at the inner surface of each passage.

3, SCR catalytic converter according to claim 2 is characterized in that: described catalyst is that zeolite based catalysts or scherbinaite are catalyst based.

4, SCR catalytic converter according to claim 1 is characterized in that: described carrier module also comprises the liner housing outer with being coated on liner that is coated on outside the carrier.

5, SCR catalytic converter according to claim 1 is characterized in that: described carrier module totally 4 groups be distributed in gas inlet pipe around.