CN211819587U - Post-treatment system for reducing ammonia emission of gas engine - Google Patents
Post-treatment system for reducing ammonia emission of gas engine Download PDFInfo
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- CN211819587U CN211819587U CN201921942309.7U CN201921942309U CN211819587U CN 211819587 U CN211819587 U CN 211819587U CN 201921942309 U CN201921942309 U CN 201921942309U CN 211819587 U CN211819587 U CN 211819587U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
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Abstract
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, include: the inlet of the TWC post-treatment device is connected with the tail gas flow outlet of the engine; an ASC/SCR catalytic device with an inlet connected with an outlet of the TWC after-treatment device; the first oxygen sensor is arranged on a connecting pipeline of the engine tail gas and the TWC after-treatment device; the second oxygen sensor and the air pump are arranged on a connecting pipeline of the TWC aftertreatment device and the ASC/SCR catalytic device; an electronic control unit for controlling the first oxygen sensor, the second oxygen sensor and the pump. The utility model adds a section of ASC/SCR catalyst behind the TWC catalyst for removing the ammonia generated by the side reaction; meanwhile, an air inlet pump is arranged in front of the ASC/SCR catalyst and is controlled by the ECU. If lambda is less than 1, the air inlet pump is started to suck air into the pipeline, oxygen in the exhaust gas is supplemented, and the ammonia oxidation rate is increased.
Description
Technical Field
The utility model belongs to the technical field of engine exhaust handles, have and relate to the aftertreatment system who reduces gas engine ammonia and discharge.
Background
Exhaust gas from a gas engine must be treated to remove nitrogen oxides, including nitrogen monoxide, nitrogen dioxide, and the like. It is well known that nitrogen oxides cause many health problems, including the formation of acid rain, etc.
The equivalent ratio routes of the gas engines disclosed in the prior art all adopt a TWC post-treatment system, the catalyst is a three-way catalyst, and a certain amount of ammonia gas is generated when the air-fuel ratio lambda is less than 1, so that the ammonia emission exceeds the regulation limit value. Meanwhile, in order to reduce NOx emission during calibration, rich conditions need to be calibrated, resulting in serious ammonia emission problems and poor engine economy due to increased gas consumption.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model aims at providing a reduce aftertreatment system that gas engine ammonia discharged, the utility model provides a system can effectively solve gas engine ammonia emission problem.
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, include:
the inlet of the TWC post-treatment device is connected with the tail gas flow outlet of the engine;
an ASC/SCR catalytic device with an inlet connected with an outlet of the TWC after-treatment device;
the first oxygen sensor is arranged on a connecting pipeline of the engine tail gas and the TWC after-treatment device;
the second oxygen sensor and the air pump are arranged on a connecting pipeline of the TWC aftertreatment device and the ASC/SCR catalytic device;
an electronic control unit for controlling the first oxygen sensor, the second oxygen sensor and the pump.
Preferably, the TWC aftertreatment device includes a TWC catalyst therein.
Preferably, the ASC/SCR catalytic device comprises:
a honeycomb carrier;
an ASC coating disposed on the honeycomb support;
an SCR coating disposed on the ASC coating.
Preferably, the honeycomb carrier is a ceramic cordierite or a metal carrier, and the ASC coating is a pure Pt noble metal catalyst; the SCR coating is a copper-based molecular sieve catalyst.
Preferably, the electronic control unit calculates a lambda value of the current system through signals of the first oxygen sensor and the second oxygen sensor, if lambda is less than 1, the air inlet pump is started, and the flow rate of the air pump is 5-10 kg/h; when lambda is greater than 1.1, the intake pump is turned off.
Preferably, the honeycomb carrier has a specification of 400/4 or 600/3,400/600 for mesh size, 4/3 for wall thickness in thousandths of an inch.
Preferably, the ASC coating is a noble metal catalyst and the active component is Pt.
Preferably, the SCR coating is a copper-based molecular sieve catalyst, and the active ingredient is CuO.
Compared with the prior art, the utility model provides a reduce aftertreatment system that gas engine ammonia discharged, include: the inlet of the TWC post-treatment device is connected with the tail gas flow outlet of the engine; an ASC/SCR catalytic device with an inlet connected with an outlet of the TWC after-treatment device; the first oxygen sensor is arranged on a connecting pipeline of the engine tail gas and the TWC after-treatment device; the second oxygen sensor and the air pump are arranged on a connecting pipeline of the TWC aftertreatment device and the ASC/SCR catalytic device; an electronic control unit for controlling the first oxygen sensor, the second oxygen sensor and the pump. The utility model adds a section of ASC/SCR catalyst behind the TWC catalyst for removing the ammonia generated by the side reaction; simultaneously, for oxygen is not enough when solving lambda < 1, the ammonia is by the slower problem of oxidation, the utility model discloses arrange an air inlet pump in front of the ASC SCR catalyst, by ECU control. After signals of the oxygen sensors 1 and 2 are transmitted to the ECU, the ECU calculates the current lambda value according to the model, if the lambda is judged to be less than 1, the air inlet pump is started to suck a small amount of air into the pipeline, oxygen in exhaust gas is supplemented, and the ammonia oxidation rate is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic diagram of the connection of an aftertreatment system for reducing ammonia emissions from a gas engine according to the present invention;
1 is a TWC after-treatment device, 2 is an ASC/SCR catalytic device, 3 is a first oxygen sensor, 4 is a second oxygen sensor, 5 is an electronic control unit, and 6 is an air pump;
FIG. 2 is a schematic view of an ASC/SCR catalytic device according to the present invention;
7 is a honeycomb carrier; 8 is ASC coating; and 9 is an SCR coating.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
A post-processing system: the device is used for treating pollutants such as nitrogen oxides, hydrocarbon, carbon monoxide and the like, and is connected to an exhaust pipe of the engine, and the treatment of the pollutants in the exhaust gas is mainly realized through an SCR technology, a DOC technology, a TWC technology and the like, so that the environmental pollution caused by the exhaust gas discharged by the engine is reduced.
Catalyst: the material can increase the chemical reaction rate, and the quality and the composition of the material are kept unchanged before and after the chemical reaction, and is used for reducing the pollutants in the tail gas of the engine, and comprises an SCR catalyst, a TWC catalyst, an ASC catalyst and the like.
The utility model discloses the device can be connected on the blast pipe of engine, is used for purifying engine exhaust promptly.
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, include:
the inlet of the TWC post-treatment device is connected with the tail gas flow outlet of the engine;
an ASC/SCR catalytic device with an inlet connected with an outlet of the TWC after-treatment device;
the first oxygen sensor is arranged on a connecting pipeline of the engine tail gas and the TWC after-treatment device;
the second oxygen sensor and the air pump are arranged on a connecting pipeline of the TWC aftertreatment device and the ASC/SCR catalytic device;
an electronic control unit for controlling the first oxygen sensor, the second oxygen sensor and the pump.
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, including the TWC aftertreatment device that entry and engine exhaust gas flow outlet link to each other.
The TWC post-processing device of the present invention is not limited, and may be one known to those skilled in the art. The TWC aftertreatment device includes a TWC catalyst therein.
The three-way catalyst is prepared with Pt, Rh and Pd as active components, the first carrier of cordierite, gamma-Al2O3As a second support (active coating), gamma-Al2O3Coated on cordierite with melting point up to 1350 deg.C and made of gamma-Al2O3Ce, La, Ba, Zr and the like are added as modification aids, which can enhance the thermal stability of the alumina and reduce the loss of specific surface areaAnd the dispersion degree of the noble metal can be improved, the metal aggregation can be prevented, and the water gas conversion can be promoted. The active component is gamma-Al dispersed in large specific surface area by impregnation method2O3The above. As for the three-way catalyst for the vehicle, the incomplete combustion is caused by various reasons in the combustion process of the fuel of the internal combustion engine, and the exhaust gas component of the incomplete combustion is carbon dioxide (CO)2) Water vapor (H)2O), carbon monoxide (CO), Hydrocarbons (HC), Nitrogen Oxides (NOX), lead compounds, sulfur compounds, and the like. Wherein carbon monoxide (CO), Hydrocarbon (HC), and Nitrogen Oxide (NO)X) Are three main gaseous pollutants causing environmental pollution.
After engine tail gas passes through TWC catalyst, CH in tail gas4CO and NOx are subjected to oxidation-reduction reaction and respectively changed into CO2，H2O，N2However, some byproducts are produced, such as CO and H produced by steam reforming2Has certain reducibility, and can reduce NOx into NH under the condition that lambda is less than 1, namely under the condition of rich combustion3The following formula shows:
CcHh+cH2O→cCO+(c+0.5h)H2formula (1)
NO+2.5H2→NH3+H2O type (2)
2NO+5CO+3H2O→2NH3+5CO2Formula (3)
From the above, it is known that the ammonia emission of a gas engine using TWC alone is easily out of limits.
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, including the entry with ASC SCR catalytic unit that TWC aftertreatment device export links to each other.
According to the utility model discloses, ASC SCR catalytic unit includes:
a honeycomb carrier;
an ASC coating disposed on the honeycomb support;
an SCR coating disposed on the ASC coating.
In the present invention, the ASC/SCR catalytic device includes a honeycomb carrier. The present invention is not limited to the honeycomb carrier, and those skilled in the art will appreciate that the honeycomb carrier may include, but is not limited to, a ceramic cordierite or a metal carrier.
The preferred specification for the thickness of the honeycomb carrier is 400/4 or 600/3,400/600 for mesh number, 4/3 for wall thickness in thousandths of an inch.
In the present invention, the ASC/SCR catalytic device includes an ASC coating disposed on the honeycomb carrier. The ASC coating is not limited by the present invention and is well known to those skilled in the art, and is preferably a pure Pt noble metal catalyst.
The thickness of the ASC coating is preferably 15-20 mu m; the ASC coating is a noble metal catalyst, and the active component is Pt.
In the present invention, the ASC/SCR catalytic device includes an SCR coating disposed on the ASC coating. The SCR coating is not limited and is well known to those skilled in the art, and is preferably a copper-based molecular sieve catalyst. The SCR coating is a copper-based molecular sieve catalyst, and the active ingredient is CuO. The thickness of the SCR is preferably 50-65 um.
The ASC coating can promote NH3Selective oxidation to N2SCR coatings promote NOx and NH3Selective catalytic reduction to N2And H2O。
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, including set up in first oxygen sensor on engine exhaust and the TWC aftertreatment device connecting line.
The utility model discloses it is right the model and the specification of first oxygen sensor do not prescribe a limit to, as long as can give ECU oxygen signal can.
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, including set up in second oxygen sensor and air pump on TWC aftertreatment device and ASC SCR catalytic unit connecting line.
The utility model discloses right the model and the specification of second oxygen sensor do not prescribe a limit to, as long as can give ECU oxygen signal can. The utility model discloses right the specification of the model of air pump is not injectd, as long as can air flow rate can.
In the present invention, "first" and "second" in the first oxygen sensor and the second oxygen sensor are used only for distinction, and do not represent a sequence.
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, including be used for right first oxygen sensor, second oxygen sensor and pump carry out the electronic control unit who controls. The utility model discloses it is right ECU does not prescribe a limit to, can carry out signal entrapment and control with first oxygen sensor, second oxygen sensor and pump can.
The utility model discloses ASC SCR catalyst theory of operation:
1) at λ > 1, NH3Reacting with oxygen to generate N under the action of ASC catalyst2Or NOx, NOx with NH under the action of SCR coatings3Generating N2And H2O, the reaction formula is as follows:
2) at λ < 1, NH3The reaction of formula (6) takes place under the action of an SCR catalyst, thereby removing NH3. However, the formula (6) is a slow reaction (reaction rate is slow), and treats NH3The efficiency is very low, and for solving lambda < 1 the oxygen is not enough, and the ammonia is by the slower problem of oxidation, the utility model discloses arrange an air intake pump in front of the ASC SCR catalyst, by ECU control. After the signals of the first oxygen sensor and the second oxygen sensor are transmitted to the ECU, the ECU calculates the current lambda value according to the model, if the lambda is judged to be less than 1, the air inlet pump is started to suck a small amount of air into the pipeline and supplement oxygen in the exhaust gas, so that the reaction formulas (4) and (5) are carried out, and the ammonia oxidation rate is improved.
Namely: the electronic control unit calculates the lambda value of the current system through signals of the first oxygen sensor and the second oxygen sensor, if lambda is judged to be less than 1, the air inlet pump is started, and the flow rate of the air pump is 5-10 kg/h; when lambda is greater than 1.1, the intake pump is turned off.
Through the utility model discloses a post-processing system, gas engine ammonia emission problem can be effectively solved, thereby reduce the engine and mark the degree of difficulty, mark the in-process for reducing NOx and discharge, need mark for the rich condition of burning, it is serious to lead to ammonia emission problem, and the gas consumption increases and leads to engine economy not good, through increase ASC SCR catalyst behind the TWC catalyst, need not to mark too concentrated, and TWC can suitably relax to NOx's processing requirement, NOx can be got rid of by following SCR catalyst, therefore can solve certain demarcation problem and engine economy.
The utility model provides a reduce aftertreatment system that gas engine ammonia discharged, include: the inlet of the TWC post-treatment device is connected with the tail gas flow outlet of the engine; an ASC/SCR catalytic device with an inlet connected with an outlet of the TWC after-treatment device; the first oxygen sensor is arranged on a connecting pipeline of the engine tail gas and the TWC after-treatment device; the second oxygen sensor and the air pump are arranged on a connecting pipeline of the TWC aftertreatment device and the ASC/SCR catalytic device; an electronic control unit for controlling the first oxygen sensor, the second oxygen sensor and the pump. The utility model adds a section of ASC/SCR catalyst behind the TWC catalyst for removing the ammonia generated by the side reaction; simultaneously, for oxygen is not enough when solving lambda < 1, the ammonia is by the slower problem of oxidation, the utility model discloses arrange an air inlet pump in front of the ASC SCR catalyst, by ECU control. After signals of the oxygen sensors 1 and 2 are transmitted to the ECU, the ECU calculates the current lambda value according to the model, if the lambda is judged to be less than 1, the air inlet pump is started to suck a small amount of air into the pipeline, oxygen in exhaust gas is supplemented, and the ammonia oxidation rate is improved.
To further illustrate the present invention, the following detailed description will be made of an aftertreatment system for reducing ammonia emission of a gas engine according to the present invention with reference to the embodiments.
Example 1
According to the connecting device of the utility model, the tail gas of the engine is sequentially connected with the first oxygen sensor, the TWC after-treatment device, the second oxygen sensor, the air pump and the ASC/SCR catalytic device; the ASC/SCR catalytic device comprises a metal carrier, a pure Pt precious metal catalyst layer with the thickness of 18 microns arranged on the metal carrier, a copper-based molecular sieve catalyst layer with the thickness of 60 microns arranged on the pure Pt precious metal catalyst layer, and an ECU (electronic control unit) used for controlling the first oxygen sensor, the second oxygen sensor and the pump.
Example 2
The engine exhaust (with a pollution gas content of 24ppm) passes through the device connected with the embodiment 1 of the utility model, and the gas content after treatment is 4 ppm.
Claims (8)
1. An aftertreatment system for reducing ammonia emissions from a gas engine, comprising:
the inlet of the TWC post-treatment device is connected with the tail gas flow outlet of the engine;
an ASC/SCR catalytic device with an inlet connected with an outlet of the TWC after-treatment device;
the first oxygen sensor is arranged on a connecting pipeline of the engine tail gas and the TWC after-treatment device;
the second oxygen sensor and the air pump are arranged on a connecting pipeline of the TWC aftertreatment device and the ASC/SCR catalytic device;
an electronic control unit for controlling the first oxygen sensor, the second oxygen sensor and the pump.
2. The system of claim 1, wherein the TWC aftertreatment device includes a TWC catalyst therein.
3. The system of claim 1, wherein the ASC/SCR catalytic device comprises:
a honeycomb carrier;
an ASC coating disposed on the honeycomb support;
an SCR coating disposed on the ASC coating.
4. The system of claim 3, wherein the honeycomb support is a ceramic cordierite or a metal support, the ASC coating is a pure Pt precious metal catalyst; the SCR coating is a copper-based molecular sieve catalyst.
5. The system of claim 1, wherein the electronic control unit calculates a lambda value of a current system through signals of the first oxygen sensor and the second oxygen sensor, if lambda is judged to be less than 1, the air inlet pump is started, and the flow rate of the air pump is 5-10 kg/h; when lambda is greater than 1.1, the intake pump is turned off.
6. The system of claim 3, wherein the honeycomb carrier has a specification of 400/4 or 600/3.
7. The system of claim 3, wherein the ASC coating is a precious metal catalyst and the active component is Pt.
8. The system of claim 3, wherein the SCR coating is a copper-based molecular sieve catalyst and the active ingredient is CuO.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921942309.7U CN211819587U (en) | 2019-11-11 | 2019-11-11 | Post-treatment system for reducing ammonia emission of gas engine |
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| CN201921942309.7U CN211819587U (en) | 2019-11-11 | 2019-11-11 | Post-treatment system for reducing ammonia emission of gas engine |
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| CN211819587U true CN211819587U (en) | 2020-10-30 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113217148A (en) * | 2021-06-01 | 2021-08-06 | 广西玉柴机器股份有限公司 | Method and system for realizing ultralow emission of natural gas engine |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113217148A (en) * | 2021-06-01 | 2021-08-06 | 广西玉柴机器股份有限公司 | Method and system for realizing ultralow emission of natural gas engine |
| WO2022252578A1 (en) * | 2021-06-01 | 2022-12-08 | 广西玉柴机器股份有限公司 | Method and system for implementing ultra-low emission of natural gas engine |
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