CN114151178A - Reducing agent injection and control method for marine SCR system - Google Patents

Reducing agent injection and control method for marine SCR system Download PDF

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Publication number
CN114151178A
CN114151178A CN202111483740.1A CN202111483740A CN114151178A CN 114151178 A CN114151178 A CN 114151178A CN 202111483740 A CN202111483740 A CN 202111483740A CN 114151178 A CN114151178 A CN 114151178A
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China
Prior art keywords
reducing agent
injection
engine
unit
exhaust
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CN202111483740.1A
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Chinese (zh)
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杨新伟
郭江峰
李冰
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China Shipbuilding Power Group Co ltd
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China Shipbuilding Power Group Co ltd
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Priority to CN202111483740.1A priority Critical patent/CN114151178A/en
Publication of CN114151178A publication Critical patent/CN114151178A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F01N3/2892—Exhaust flow directors or the like, e.g. upstream of catalytic device
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/14—Nitrogen oxides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • F01N2610/146—Control thereof, e.g. control of injectors or injection valves
    • 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
    • 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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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

The marine SCR system comprises an engine exhaust manifold, cylinders respectively connected with the engine exhaust manifold, an injection unit, a metering unit, a supply unit, a storage unit and a monitoring control unit respectively connected with the injection unit, the metering unit, the supply unit and the storage unit, wherein the injection unit comprises a plurality of spray guns arranged at the joints of the engine exhaust manifold and the cylinders, the engine exhaust manifold is used as a reducing agent evaporation and mixing unit, and the reducing agent is directly injected into the engine exhaust manifold through the injection unit. The invention improves the precision of the reducing agent, improves the utilization rate of the reducing agent, fully utilizes the waste heat of the exhaust gas of the engine, improves the decomposition efficiency of the reducing agent and the mixing uniformity of the reducing agent and the exhaust gas, and effectively promotes the improvement of the purification efficiency of the marine SCR system.

Description

Reducing agent injection and control method for marine SCR system
Technical Field
The invention relates to the fields of atmospheric environment treatment, ship power and the like, in particular to a reducing agent injection and control method for a selective catalytic reduction denitration System (SCR) for purifying nitrogen oxides in tail gas of a ship engine, which can effectively promote the decomposition of a reducing agent and the mixing uniformity of waste gas and improve the utilization rate of the reducing agent.
Technical Field
The selective catalytic reduction denitration technology is one of the most effective methods for purifying nitrogen oxides (NOx) in tail gas of marine engines at present. One of the key factors affecting the purification efficiency of the SCR technology is the efficient pyrolysis and mixing technology of the reducing agent. At the same time, limited by NH3The regulation of slip (typically 10ppm) places higher demands on the mixing uniformity of the SCR reductant. In addition, with marine SCR technology, this undoubtedly presents a significant challenge to the efficient decomposition of the reductant due to the relatively low engine exhaust temperatures. In addition, the space of the cabin is generally narrow, and it is difficult to arrange a sufficient reducing agent evaporation mixing pipe, which is very unfavorable for the efficient mixing of the reducing agent. Therefore, in order to overcome the problems, the technical characteristics of the marine SCR are required to be fully combined, and the technology for injecting the reducing agent on the ship is required to be developed.
Korean bucket mountain and modern companies introduced urea injection technology of a urea evaporation decomposer (UDC) in low pressure selective catalytic reduction denitration technology (LP-SCR) for ships, injecting a reducing agent into the equipment while heating the decomposer using external heat supply equipment, thereby promoting efficient pyrolysis and mixing of the reducing agent. However, the method has the disadvantages of more introduced equipment, complex control, difficult arrangement and difficult popularization and application. In seven marine engine research institutes in China, the method of directly injecting the reducing agent into the evaporation mixing pipe in the low-pressure selective catalytic reduction denitration system utilizes the action of the catalyst to promote the decomposition of the reducing agent, but the method has the defect of high risk of ammonia escape.
Disclosure of Invention
The invention aims to provide a reducing agent injection and control technology of a marine SCR system, which combines the performance and the structural characteristics of an engine, arranges corresponding reducing agent spray guns at the joints of exhaust valves and exhaust manifolds of cylinders, and ensures that the injection sequence of the reducing agent of each spray gun is the same as the ignition sequence of the cylinders of the engine.
The technical solution of the invention is as follows:
the marine SCR system comprises an engine exhaust manifold, cylinders respectively connected with the engine exhaust manifold, an injection unit, a metering unit, a supply unit, a storage unit and a monitoring control unit respectively connected with the injection unit, the metering unit, the supply unit and the storage unit.
The number of the spray guns is the same as that of the air cylinders, and the spray guns are arranged at the connecting pipes of the air cylinders and the exhaust manifold, namely the rear ends of the exhaust valves.
Each reducing agent spray gun adopts an intermittent pulse injection mode, the opening sequence is the same as the firing sequence of each cylinder of the engine, the injection duration is kept consistent with the exhaust timing of the engine, namely the opening time of an exhaust valve of the engine is kept the same, so that the reducing agent sprayed by the spray gun is fully mixed with the exhaust gas discharged by the cylinders, and then enters an exhaust manifold of the engine for further mixing.
The monitoring control unit is used for monitoring the load, the rotating speed, the exhaust temperature, the exhaust pressure and the exhaust timing of the engine and controlling the start-stop and the injection flow of each spray gun of the injection unit by controlling the supply unit and the metering unit.
When the monitoring control unit monitors that the exhaust temperature of the engine meets the conditions and the exhaust valve of the cylinder is opened, the corresponding spray gun is controlled to spray the reducing agent, and the injection quantity of the reducing agent is determined by the load and the rotating speed of the engine; and when the exhaust valve of the cylinder is closed, controlling the spray gun to stop injecting the reducing agent.
The exhaust temperature is above 280 ℃.
The reducing agent is one or more of ammonia water, urea solution and other solutions.
The invention is suitable for a high-pressure selective catalytic reduction denitration system and a low-pressure selective catalytic reduction denitration system. The SCR system can be suitable for the tail gas SCR system of marine engines with different fuels such as diesel oil, natural gas, liquefied petroleum gas, methanol, ammonia gas and the like.
Compared with the prior art, the invention has the following beneficial effects:
the novel reducing agent injection method for the marine SCR system fully combines the performance and the structural characteristics of an engine, and a corresponding reducing agent spray gun is arranged at the joint of each cylinder exhaust valve and an exhaust manifold. The injection sequence of the reducing agent of each spray gun is the same as the ignition sequence of the engine cylinder. The invention has the advantages of full engine exhaust characteristics, and high decomposition efficiency and mixing uniformity of the reducing agent can be obtained due to the high exhaust temperature of the exhaust manifold.
Drawings
FIG. 1 is a schematic diagram of a reductant injection system for a marine SCR system of the present invention
FIG. 2 is a schematic view of the reduction lance arrangement of the present invention
FIG. 3 is a flow chart of a method for reducing agent injection and control of a marine SCR system of the present invention
Detailed description of the invention
The present invention is described in detail below with reference to specific examples, but the scope of the present invention is not limited thereto.
Fig. 1 mainly includes a reducing agent storage tank, a reducing agent supply unit, a reducing agent injection unit, and a reducing agent system monitoring control unit. As shown in FIG. 2, a reducing agent spray gun is arranged at the connection position of each cylinder of an exhaust manifold of an engine, and the spray gun is connected with a reducing agent metering unit and a storage unit. Fig. 3 shows the main components of the control unit, including monitoring engine load, speed, exhaust pipe pressure, engine exhaust timing signals, and control operations including reductant injection sequence, injection start time, injection duration, and injection flow rate.
The MAP of the injection quantity of the reducing agent and the engine load rotating speed MAP is input into the control unit in advance through experimental calibration. During actual operation of the system, the control unit monitors signals such as an engine load signal, a rotating speed signal, an exhaust manifold pressure temperature and exhaust timing in real time. The temperature of the exhaust pipe of the engine is not lower than 280 ℃, and the reducing agent injection system enters a ready state. When the engine reaches the set operation load, the reducing agent supply unit and the metering unit supply the reducing agent to the spray gun according to the reducing agent injection quantity corresponding to the MAP. The sequence of gun injections on each cylinder is determined by the engine exhaust timing. As shown in FIG. 1, assuming that the firing order of the cylinders is 1-5-2-4-3, the opening order of the exhaust valves of the cylinders is also 1-5-2-4-3. When the exhaust valve of the No. 1 cylinder is opened, a reducing agent spray gun (shown in figures 1 and 2) arranged at the rear end of the exhaust valve of the cylinder is opened to spray reducing agent, and after the exhaust valve is closed, the reducing agent spray gun stops spraying the reducing agent. And when the exhaust valve of the No. 5 cylinder is opened, the corresponding reducing agent spray gun is opened to spray the reducing agent. In this sequence, the injection of reductant for one cycle is completed. The injection amount of the reducing agent per unit time is equal to the value in the MAP calibrated by the experiment.
The injected reductant is thoroughly mixed with the cylinder exhaust in the exhaust manifold and then further mixed in the engine exhaust manifold. Because the temperature of the exhaust gas is higher when the cylinder exhausts, the decomposition efficiency of the reducing agent can be fully improved by the reducing agent injection method, and meanwhile, because the reducing agent after injection rapidly enters the exhaust manifold of the engine, because the exhaust manifold has large volume and high turbulence intensity of the exhaust gas, the reducing agent can be fully mixed with the exhaust gas.
If monitoring signals such as temperature, pressure and the like exceed a set range, a control system is triggered to alarm, and the reducing agent supply unit immediately stops supplying the reducing agent so as to protect the whole reducing agent system; if the engine cylinder is not fired normally, such as the exhaust timing signal is abnormal, the system will also immediately terminate the supply of the reducing agent.
Example 1:
the novel reducing agent injection technology is applied to a high-pressure selective catalytic reduction denitration system (HP-SCR) for a ship, is installed on a MAN 6S50ME-C8.2 low-speed engine (rated power of 9960kW and rotating speed of 127rpm), is provided with 6 reducing agent spray guns, and is installed at a connecting pipe of each cylinder and an exhaust manifold. The exhaust timing of the engine is 1-5-2-4-3-6, each spray gun of the reducing agent adopts intermittent pulse type injection, the duration of each spraying is 0.17s, and the injection sequence is the same as the exhaust timing of the engine. Urea is used as a reducing agent, and the urea injection flow is 140L/h at 100 loads. Warp beamTest shows that the decomposition rate of the reducing agent is 97.3 percent, the mixing uniformity is 96.6 percent, the purification efficiency of nitrogen oxide (NOx) is 86.7 percent, and NH is added3The escape was 7 ppm.
Example 2:
the novel reducing agent injection technology is applied to a low-pressure selective catalytic reduction denitration system (HP-SCR) for a ship, is installed on a MAN 6S50ME-C8.2 low-speed engine (rated power of 9960kW and rotating speed of 127rpm), is provided with 6 reducing agent spray guns, and is installed at a connecting pipe of each cylinder and an exhaust manifold. The exhaust timing of the engine is 1-5-2-4-3-6, each spray gun of the reducing agent adopts intermittent pulse type injection, the duration of each spraying is 0.17s, and the injection sequence is the same as the exhaust timing of the engine. Urea is used as a reducing agent, and the urea injection flow is 140L/h at 100 loads. Through test detection, the decomposition rate of the reducing agent is 96.9%, the mixing uniformity is 97.4%, the purification efficiency of nitrogen oxide (NOx) is 81.3%, and NH is3The escape was 1 ppm.
Example 3:
the novel reducing agent injection technology is applied to a marine high-pressure selective catalytic reduction denitration system (HP-SCR), is installed on a WinGD 11X92-B marine low-speed engine (rated power of 63000kW and rotating speed of 79rpm), is provided with 11 reducing agent spray guns, and is installed at a connecting pipe of each cylinder and an exhaust header. The exhaust timing of the engine is 1-10-3-7-2-11-4-8-6-9-5, each spray gun of the reducing agent adopts intermittent pulse type injection, the duration of each spraying is 0.27s, and the injection sequence is the same as the exhaust timing of the engine. Urea is used as a reducing agent, and the urea injection flow rate is 896L/h at 100 loads. Through test detection, the decomposition rate of the reducing agent is 94.6%, the mixing uniformity is 96.9%, the purification efficiency of nitrogen oxide (NOx) is 91.1%, and NH is3The escape was 1 ppm.
Example 4:
the novel reducing agent injection technology is applied to a low-pressure selective catalytic reduction denitration system (LP-SCR) for a ship, is installed on a WinGD 11X92-B low-speed engine (rated power of 63000kW and rotating speed of 79rpm), is provided with 11 reducing agent spray guns, and is installed at a connecting pipe of each cylinder and an exhaust header. The exhaust timing of the engine is 1-10-3-7-2-11-4-8-6-9-5, and each spray gun of the reducing agent adoptsIntermittent pulse type injection, each spraying duration is 0.27s, and the injection sequence is the same as the exhaust timing of the engine. Urea is used as a reducing agent, and the urea injection flow rate is 390L/h at 25 loads. Tests show that the decomposition rate of the reducing agent is 95.1%, the mixing uniformity is 97.2%, the purification efficiency of nitrogen oxide (NOx) is 80.3%, and NH is added3The escape was 7 ppm.
Example 5:
the novel reducing agent injection technology is applied to a high-pressure selective catalytic reduction denitration system (HP-SCR) for a ship, is installed on a MAN 6S50ME-C8.2 low-speed engine (rated power of 9960kW and rotating speed of 127rpm), is provided with 6 reducing agent spray guns, and is installed at a connecting pipe of each cylinder and an exhaust manifold. The exhaust timing of the engine is 1-5-2-4-3-6, each spray gun of the reducing agent adopts intermittent pulse type injection, the duration of each spraying is 0.17s, and the injection sequence is the same as the exhaust timing of the engine. Ammonia water is used as a reducing agent, and the urea injection flow rate is 210L/h at 100 loads. Tests show that the decomposition rate of the reducing agent is 99.4%, the mixing uniformity is 97.4%, the purification efficiency of nitrogen oxide (NOx) is 83.2%, and NH is added3The escape was 2 ppm.
Example 6:
the novel reducing agent injection technology is applied to a high-pressure selective catalytic reduction denitration system (HP-SCR) for a ship, is installed on a liquefied petroleum gas fuel MAN 6G70ME-LGIP low-speed engine (rated power 15600kW, rotating speed 90rpm), is provided with 6 reducing agent spray guns, and is installed at a connecting pipe of each cylinder and an exhaust manifold. The exhaust timing of the engine is 1-5-2-4-3-6, each spray gun of the reducing agent adopts intermittent pulse type injection, the duration of each spraying is 0.24s, and the injection sequence is the same as the exhaust timing of the engine. Urea is used as a reducing agent, and the urea injection flow is 180L/h at 100 loads. Through test detection, the decomposition rate of the reducing agent is 96.2%, the mixing uniformity is 98.4%, the purification efficiency of nitrogen oxide (NOx) is 84.1%, and NH is generated3The escape was 2 ppm.
The above embodiment shows that the reducing agent spray gun behind each cylinder adopts an intermittent pulse injection mode, the opening sequence of the intermittent pulse injection mode is the same as the exhaust timing of each cylinder of the engine, and the reducing injection duration is the same as the exhaust timing of the cylinder, namely when the exhaust valve is opened, the reducing agent spray gun starts to inject, the reducing agent is fully mixed with the exhaust gas discharged by the cylinder, then the reducing agent enters the exhaust manifold of the engine to be further mixed, and after the exhaust valve is closed, the spray gun stops injecting. The control unit monitors engine signals such as engine load, rotating speed, exhaust temperature, exhaust pressure and exhaust timing, and controls parameters such as the start and stop of the injection of the reducing agent and the injection flow rate by controlling the supply unit and the metering unit. The invention fully improves the precision of the reducing agent, improves the utilization rate of the reducing agent, can fully utilize the waste heat of the exhaust gas of the engine, improves the decomposition efficiency of the reducing agent and the mixing uniformity of the reducing agent and the exhaust gas, and effectively promotes the improvement of the purification efficiency of the marine SCR system.

Claims (7)

1. The marine SCR system comprises an engine exhaust manifold, cylinders respectively connected with the engine exhaust manifold, an injection unit, a metering unit, a supply unit, a storage unit and a monitoring control unit respectively connected with the injection unit, the metering unit, the supply unit and the storage unit.
2. The method of claim 1, wherein the number of spray guns is the same as the number of cylinders, and the spray guns are arranged at the connecting pipe of each cylinder and the exhaust manifold, namely the rear end of the exhaust valve.
3. The marine SCR system reducing agent injection and control method according to claim 1 or 2, wherein each reducing agent spray gun adopts an intermittent pulse injection mode, the opening sequence is the same as the firing sequence of each cylinder of the engine, the injection duration is consistent with the engine exhaust timing, namely the engine exhaust valve opening time, so that the reducing agent sprayed by the spray gun is fully mixed with the exhaust gas discharged by the cylinders, and then enters the engine exhaust manifold for further mixing.
4. The reductant injection and control method for marine SCR system as defined in claim 3, wherein said monitoring and control unit is used for monitoring engine load, speed, exhaust temperature, exhaust pressure, and exhaust timing, and controlling the start-stop and injection flow rate of each spray gun of said injection unit by controlling said supply unit and said metering unit.
5. The marine SCR system reductant injection and control method of claim 4, wherein when the monitoring and control unit monitors that the exhaust temperature of the engine meets the condition and the exhaust valve of the cylinder is opened, the corresponding spray gun is controlled to inject the reductant, and the injection amount of the reductant is determined by the load and the rotating speed of the engine; and when the exhaust valve of the cylinder is closed, controlling the spray gun to stop injecting the reducing agent.
6. The method of claim 5, wherein the exhaust temperature is above 280 ℃.
7. The method for injecting and controlling a reducing agent in an SCR system of a ship as claimed in claim 5, wherein the reducing agent is one or more of ammonia water, urea solution and the like.
CN202111483740.1A 2021-12-07 2021-12-07 Reducing agent injection and control method for marine SCR system Pending CN114151178A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0650133A (en) * 1992-07-27 1994-02-22 Mitsubishi Heavy Ind Ltd Denitration device of internal combustion engine
JP2001280125A (en) * 2000-03-31 2001-10-10 Toyota Motor Corp Exhaust exmission control device for internal combustion engine
CN103210189A (en) * 2010-11-02 2013-07-17 日立造船株式会社 Exhaust gas emission purification device
CN109973187A (en) * 2019-03-29 2019-07-05 无锡威孚力达催化净化器有限责任公司 Marine diesel post-processes control method and control device
TW202030016A (en) * 2019-01-30 2020-08-16 日商三菱日立電力系統股份有限公司 Reducing agent supply device and denitrification apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0650133A (en) * 1992-07-27 1994-02-22 Mitsubishi Heavy Ind Ltd Denitration device of internal combustion engine
JP2001280125A (en) * 2000-03-31 2001-10-10 Toyota Motor Corp Exhaust exmission control device for internal combustion engine
CN103210189A (en) * 2010-11-02 2013-07-17 日立造船株式会社 Exhaust gas emission purification device
TW202030016A (en) * 2019-01-30 2020-08-16 日商三菱日立電力系統股份有限公司 Reducing agent supply device and denitrification apparatus
CN109973187A (en) * 2019-03-29 2019-07-05 无锡威孚力达催化净化器有限责任公司 Marine diesel post-processes control method and control device

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