CN116838458A - SCR closed-loop control device and control method - Google Patents
SCR closed-loop control device and control method Download PDFInfo
- Publication number
- CN116838458A CN116838458A CN202310724538.6A CN202310724538A CN116838458A CN 116838458 A CN116838458 A CN 116838458A CN 202310724538 A CN202310724538 A CN 202310724538A CN 116838458 A CN116838458 A CN 116838458A
- Authority
- CN
- China
- Prior art keywords
- time
- power
- sensor
- nox
- supply
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 22
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 80
- 239000004202 carbamide Substances 0.000 claims abstract description 80
- 238000006243 chemical reaction Methods 0.000 claims abstract description 30
- 238000004891 communication Methods 0.000 claims abstract description 8
- 238000001514 detection method Methods 0.000 claims description 5
- 238000012360 testing method Methods 0.000 claims description 4
- 238000005259 measurement Methods 0.000 claims description 3
- 230000036962 time dependent Effects 0.000 claims description 3
- 230000001276 controlling effect Effects 0.000 description 7
- 239000007921 spray Substances 0.000 description 6
- 239000007789 gas Substances 0.000 description 4
- 238000010531 catalytic reduction reaction Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- 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
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
- F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
-
- 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
- F01N2610/1433—Pumps
-
- 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
-
- 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
- F01N2610/148—Arrangement of sensors
-
- 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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
- F01N2900/1402—Exhaust gas composition
-
- 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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/18—Parameters used for exhaust control or diagnosing said parameters being related to the system for adding a substance into the exhaust
- F01N2900/1806—Properties of reducing agent or dosing system
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
The application discloses an SCR closed-loop control device and a control method. The SCR closed-loop control device comprises a supply system, a reaction system, a control system and a power system; the supply system comprises a flow sensor and a control valve, the flow sensor is used for detecting the urea supply quantity of the supply system, and the control valve is used for controlling the urea supply quantity output by the supply system; the reaction system comprises a first sensor and a second sensor, wherein the first sensor is arranged at an air inlet of the reaction system and is used for detecting the concentration of NOx at the air inlet of the reaction system; the second sensor is arranged at the air outlet of the reaction system and is used for detecting the concentration of NOx at the air outlet of the reaction system; the control system is respectively in communication connection with the first sensor, the second sensor, the control valve and the power system; the power system transmits the real-time operating load to the control system. The application can control the NOx emission within the set target NOx range by changing the input parameters of the control system.
Description
Technical Field
The application relates to a ship engine tail gas denitration device, in particular to an SCR closed-loop control device and a control method.
Background
Ships are one of the most important transportation tools for the economic development of the society nowadays, and with the increasing number of transportation ships, the emission of exhaust pollutants NOx and the like of ship engines is also becoming serious, which has serious influence on the air environment in coastal and river-like areas. The ship denitration device is also called as a selective catalytic reduction device (SCR), and can react a reducing agent with NOx in tail gas under the condition of heating at the temperature of flue gas through the action of a catalyst to generate nontoxic pollution-free nitrogen and water.
At present, most of shipping SCR is in an open loop control mode, namely various diesel engines meet emission requirements, urea supply quantity of the SCR is calibrated under various working conditions during emission tests of a main engine plant, and a MAP graph of diesel engine power and urea supply quantity is formed. After SCR (selective catalytic reduction) shipment, the urea supply and the diesel engine power are solidified no matter whether the actual ship discharges abominably or not. The open-loop control mode cannot be fully suitable for the emission change after the service life of the diesel engine is longer and the change after the service life of the catalyst is reduced. Therefore, the SCR urea supply system adopts a closed-loop control mode, and can meet the emission change requirement of the diesel engine after long-term use, so that the ship engine meets the emission regulation limit value requirement. However, in the prior art, the closed-loop SCR urea supply system has the problems that the urea output feedback is insensitive, and the fluctuation range of NOx in the tail gas caused by the change of working conditions cannot be quickly adjusted.
Disclosure of Invention
The application aims to provide an SCR closed-loop control device and a control method. According to the application, by changing the input parameters of the control system, the NOx emission can be controlled within the set target NOx range, and the problem that the prior art cannot quickly respond to the change of the actual ship emission is solved.
The embodiment of the application provides an SCR closed-loop control device, which comprises a supply system, a reaction system, a control system for controlling the urea supply amount of the supply system and a power system;
the supply system comprises a flow sensor and a control valve, wherein the flow sensor is used for detecting the urea supply quantity of the supply system, and the control valve is used for controlling the urea supply quantity output by the supply system;
the reaction system comprises a first sensor and a second sensor, wherein the first sensor is arranged at an air inlet of the reaction system and is used for detecting the concentration of NOx at the air inlet of the reaction system;
the second sensor is arranged at the air outlet of the reaction system and is used for detecting the concentration of NOx at the air outlet of the reaction system;
the control system is respectively in communication connection with the first sensor, the second sensor, the control valve and the power system; the power system communicates a load signal to the control system.
In some embodiments, the supply system comprises a pump set for delivering urea.
In some embodiments, the reaction system includes a mixing tube and a reactor in communication with the mixing tube.
In some embodiments, the supply system includes a lance in communication with the inlet of the mixing tube.
The application also provides a control method of the SCR closed-loop control device, which comprises the following steps:
calculating theoretical urea supply quantity of SCR under different working conditions of the power system, wherein the theoretical urea supply quantity is used as an input parameter 1 of the control system;
taking the NOx concentration meeting the emission requirement as a target value, and simultaneously, taking the time period T 1 In the method, the NOx concentration mean value detected by the second sensor is compared with a NOx target value and is used as an input parameter 2 of the control system;
the power system is in a period T 2 In, taking the difference value of the urea supply quantity superposition of the power MAP as an input parameter 3 of the control system;
and calculating a set supply amount based on the input parameter 1, the input parameter 2 and the input parameter 3, wherein the control system controls the urea supply amount of the supply system according to the obtained set supply amount.
In some embodiments, the real-time flow rate of urea supply is obtained through the detection value fed back by the flow sensor, and the real-time flow rate is compared with the set supply amount to adjust the output value of the control valve.
In some embodiments, the real-time flow rate and the set supply amount are adjusted by PID as an input value to the control valve.
In some embodiments, the theoretical urea supply is obtained by: and calibrating initial urea supply amounts under different working conditions through theoretical calculation or bench test to form a MAP of power and urea supply amounts.
In some embodiments, T 1 ＝kT 2 Wherein k is a positive integer.
In some embodiments, 1.ltoreq.k.ltoreq.15.
In some embodiments, the set supply amount is calculated by:
Q＝Q 1 +Q 2 +Q 3
Q 1 ＝f(P)
Q 3 ＝Q nT2 -Q (n-1)T2 ；
wherein Q is a set supply amount, Q 1 To the theoretical urea supply quantity, Q 2 To correct the urea supply, P is the power of the power system, Q 3 Is T 2 The difference value of the urea supply quantity superposition of the power MAP in the time period is N, wherein N is the absolute value of the difference value of the NOx mean value and the NOx target value, N 1 ～N 3 Calculating a domain parameter, k, for NOx bias 1 And k 2 To adjust the ratio parameters b 1 And b 2 To adjust the amplitude parameter, T 1 And T 2 For correcting the time parameter, Q nT2 Is the nth T 2 Time-dependent power MAP urea supply, Q (n-1)T2 Is the (n-1) th T 2 The power MAP urea supply amount corresponds to time.
In some embodiments, between periods 0 and T 1 Time, Q 1 And Q 2 Calculated as follows:
at 0 to T 1 Time period, Q 1 The real-time measurement power P value is calculated and is between 0 and T 1 Time varies over time over a period of time; q (Q) 2 Calculated at 0 time and 0 to T 1 Remains unchanged for a period of time.
At T 2 ～T 1 Time period, Q 1 Calculating the power P value measured in real time, and calculating the power P value at T 2 ～T 1 Time varies over time over a period of time; q (Q) 2 Taking T 1 Calculated at the moment, at T 2 ～T 1 Remains unchanged for a period of time.
In some embodiments of the present application, in some embodiments,
wherein P is the power of the power system.
The application has the beneficial effects that: the application provides an SCR closed-loop control device and a control method. The SCR closed-loop control device comprises a supply system, a reaction system, a control system for controlling the urea supply quantity of the supply system and a power system; the SCR closed-loop control device calculates and controls the urea supply quantity through the detected NOx value, can quickly and accurately adjust the urea supply quantity output by the supply system according to the change of the working condition of the power system, and can control the NOx emission within the set target NOx range. The control method of the application enables the supply system to quickly respond to the load change of the power system, and the accurate and quick adjustment of the flow of the supply system is completed.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of an SCR closed-loop control device according to embodiment 1 of the present application;
FIG. 2 is a flow chart of embodiment 2 of the present application;
in the figure, 100-supply system, 101-flow sensor, 102-control valve, 103-pump group, 104-spray gun, 200-reaction system, 201-first sensor, 202-second sensor, 203-mixing tube, 204-reactor, 300-control system, 400-power system.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to fall within the scope of the application. In addition, in the description of the present application, the term "comprising" means "including but not limited to". The terms first, second, third and the like are used merely as labels, and do not impose numerical requirements or on the order of construction. Various embodiments of the application may exist in a range of forms; it should be understood that the description in a range format is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the application.
Example 1: as shown in fig. 1, the present application provides an SCR closed-loop control device, which includes a supply system 100, a reaction system 200, a control system 300 for controlling the urea supply amount of the supply system 100, and a power system 400.
The supply system 100 includes a flow sensor 101, a control valve 102, a pump stack 103, and a lance 104. The flow sensor 101 is used for detecting the urea supply amount of the supply system 100, the control valve 102 is used for controlling the urea supply amount output by the supply system 100, and the pump set 103 is used for conveying urea from the urea storage tank to the spray gun 104; the inlet of the spray gun 104 is communicated with the outlet of the control valve 102, the opening of the control valve 102 is adjusted to control the flow rate of urea fed into the spray gun 104, the outlet of the spray gun 104 is communicated with the inlet of the mixing pipe 203, and urea fed out from the supply system 100 is fed into the reaction system 200.
In one embodiment, the flow sensor 101 adopts an electromagnetic flowmeter, and the feedback signal output adopts 4-20mA; the control valve 102 is a proportional control valve, and the input signal is 4-20mA.
In one embodiment, the pump unit 103 delivers urea for use in a ship to the spray gun 104, the urea delivered and the exhaust gas containing NOx are catalytically reacted in the reaction system 200 to complete catalytic reduction of NOx, and the flow sensor 101 is disposed between the pump unit 103 and the control valve 102 for detecting the flow of urea into the control valve 102 in real time.
In some embodiments, the reaction system 200 includes a first sensor 201, a second sensor 202, a mixing tube 203, and a reactor 204. The first sensor 201 is disposed at an air inlet of the reaction system 200, and is used for detecting the concentration of NOx at the air inlet of the reaction system 200; the second sensor 202 is disposed at the air outlet of the reaction system 200, and is used for detecting the concentration of NOx at the air outlet of the reaction system 200. In one embodiment, the first sensor 201 is mounted at the inlet of the mixing tube 203 and the second sensor 202 is mounted at the outlet of the reactor 204.
In some embodiments, the control system 300 is communicatively coupled to the first sensor 201, the second sensor 202, the control valve 102, and the power system 400, respectively, and the power system 400 communicates a load signal to the control system 300.
In one embodiment, the power system 400 is a marine diesel engine, with the exhaust of the marine diesel engine in communication with the inlet of the mixing tube 203.
Example 2: as shown in fig. 2, the method for controlling urea flow by using the SCR closed-loop control device of the present application comprises the following steps:
calculating a theoretical urea supply amount of the SCR under different working conditions of the power system 400, wherein the theoretical urea supply amount is used as an input parameter 1 of the control system 300, and is obtained by the following steps: calibrating initial urea supply amounts under different working conditions through theoretical calculation or bench test to form a MAP of power and urea supply amounts; according to the application, the MAP (MAP) of the power and the urea supply amount is set to form the initial urea supply amount, so that the NOx value can reach the vicinity of the theoretical emission interval rapidly when the SCR operates.
Taking the NOx concentration meeting the emission requirement as a target value, and simultaneously, taking the time period T 1 In, the NOx concentration mean value detected by the second sensor 202 is compared with the NOx target value as the input parameter 2 of the control system 300; the application further compares the NOx detection value of the second sensor 202 with the NOx target value difference by the control system 300, and sets the adjustment amplitude of the urea supply amount of different gear steps at the same time, the larger the NOx difference, the larger the adjustment amplitude, and vice versa. In a specific embodiment, T 1 The time period is 10-30 s, the collected NOx detection value is the NOx average value in 10-30 s, the fluctuation of flow feedback control caused by the fluctuation of the NOx value can be effectively reduced, and the flow regulation is more stable.
Power system 400 is in time period T 2 The difference between the urea supply amounts of the power MAP is used as the input parameter 3 of the control system 300. In a particular embodiment, the powertrain 400 selects a diesel engine that varies in power over time while the urea supply flow rate is overlappingThe urea flow difference generated by the power difference of the diesel engine in the period is added to enable the urea flow to meet the rapid response when the load changes. Specifically T 1 ＝kT 2 Where k is a positive integer, in some embodiments 1.ltoreq.k.ltoreq.15, e.g., k has any of values 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, e.g., when k is 2, T 2 The time period is 5-15 s.
The set supply quantity is calculated by the input parameter 1, the input parameter 2 and the input parameter 3, and the set supply quantity=initial urea supply quantity+time period T 1 Supply amount adjustment amplitude of difference between detected NOx concentration mean value and NOx target value + period T 2 The internal MAP supply amount is superimposed by a difference value, the urea supply amount fed back is adjusted in amplitude, a real-time flow rate of the urea supply is obtained by a detection value fed back by the flow sensor 101, and the output value of the control valve 102 is adjusted by comparing the real-time flow rate with a set supply amount. In one embodiment, the detected value fed back by the flow sensor 101 is compared with a set urea supply target value, and PID adjustment is performed as an input value controlled by the control valve 102, so that a dual closed-loop control mode based on the NOx value and the flow value is obtained, and the NOx emission can be controlled within a set target NOx range.
In one specific application, the set supply amount is calculated by:
Q＝Q 1 +Q 2 +Q 3
Q 1 ＝f(P)
Q 3 ＝Q nT2 -Q (n-1)T2 ；
wherein Q is a set supply amount, Q 1 To the theoretical urea supply quantity, Q 2 To correct urea supply quantity, Q 3 Is T 2 The difference value of the urea supply quantity superposition of the power MAP in the time period, P is the power of the power system, N is the absolute value of the difference value between the NOx concentration mean value and the NOx target value, N 1 ～N 3 Calculating a domain parameter, k, for NOx bias 1 And k 2 To adjust the ratio parameters b 1 And b 2 To adjust the amplitude parameter, T 1 And T 2 For correcting the time parameter, Q nT2 Is the nth T 2 Time-dependent power MAP urea supply, Q (n-1)T2 Is the (n-1) th T 2 The power MAP urea supply amount corresponds to time.
Q nT2 Q and (n-1)T2 calculated by the following means:
a calculation period of 0 to T 1 Time, Q 1 And Q 2 Calculated as follows:
at 0 to T 1 Time period, Q 1 The real-time measurement power P value is calculated and is between 0 and T 1 Time varies over time over a period of time; q (Q) 2 Calculated at 0 time and 0 to T 1 Remains unchanged for a period of time.
At T 2 ～T 1 Time period, Q 1 Calculating the power P value measured in real time, and calculating the power P value at T 2 ～T 1 Time varies over time over a period of time; q (Q) 2 Taking T 1 Calculated at the moment, at T 2 ～T 1 Remains unchanged for a period of time.
Application example: as shown in table 1, a theoretical MAP flow of urea supply amount based on diesel engine power is set as an input parameter 1.
A difference between the NOx set point 130ppm and the NOx concentration detected by the second sensor is set as an input parameter 2:
setting N 1 ～N 3 NOx deviation calculation domain parameters of (1), e.g. respectively set to N 1 25ppm, N 2 50ppm, N 3 100ppm.
And according to the empirical value, selecting the regulating amplitude, setting the regulating proportion k of urea supply quantity of two gears 1 And k 2 And the adjustment amplitude b of the urea supply quantity of the two gears 1 And b 2 Obtaining Q according to the absolute value N of the difference between the detected NOx concentration mean value and the NOx target value 2 ，T 1 The time period can be selected to be 30s, T 2 The time period may be selected to be 10s.
TABLE 1
| P(kw) | MAP flow (L/h) | NOx set point (ppm) |
| 0.0 | 0.0 | - |
| 350.0 | 0.0 | - |
| 875.0 | 13.0 | 130.0 |
| 1400.0 | 17.0 | 130.0 |
| 1750.0 | 24.0 | 130.0 |
| 2625.0 | 32.0 | 130.0 |
| 2975.0 | 36.0 | 130.0 |
| 3500.0 | 41.0 | 130.0 |
And Q is calculated by the following method 3 :Q 3 ＝Q nT2 -Q (n-1)T2
According to the application, through controlling the urea supply quantity in three dimensions, the concentration of discharged NOx can be ensured to be in a standard range, and the accurate and rapid adjustment of the flow of a supply system can be completed.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.
The above describes in detail an SCR closed-loop control device and a control method provided by the embodiment of the present application, and specific examples are applied to describe the principle and implementation of the present application, where the description of the above embodiment is only used to help understand the method and core idea of the present application; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in light of the ideas of the present application, the present description should not be construed as limiting the present application.
Claims (13)
1. An SCR closed-loop control device, comprising a supply system (100), a reaction system (200), a control system (300) for controlling the urea supply amount of the supply system (100), and a power system (400);
the supply system (100) comprises a flow sensor (101) and a control valve (102), wherein the flow sensor (101) is used for detecting the urea supply amount of the supply system (100), and the control valve (102) is used for controlling the urea supply amount output by the supply system (100);
the reaction system (200) comprises a first sensor (201) and a second sensor (202), wherein the first sensor (201) is arranged at an air inlet of the reaction system (200) and is used for detecting the concentration of NOx at the air inlet of the reaction system (200);
the second sensor (202) is arranged at the air outlet of the reaction system (200) and is used for detecting the concentration of NOx at the air outlet of the reaction system (200);
the control system (300) is respectively in communication connection with the first sensor (201), the second sensor (202), the control valve (102) and the power system (400); the power system (400) communicates a load signal to the control system (300).
2. The SCR closed loop control device according to claim 1, wherein the supply system (100) comprises a pump group (103), the pump group (103) being adapted to deliver urea.
3. The SCR closed loop control device according to claim 2, wherein the reaction system (200) comprises a mixing tube (203) and a reactor (204) in communication with the mixing tube (203).
4. A SCR closed loop control device according to claim 3, characterized in that the supply system (100) comprises a lance (104), the lance (104) being in communication with the inlet of the mixing tube (203).
5. The control method of the SCR closed-loop control device according to claim 1, comprising the steps of:
calculating theoretical urea supply amounts of SCR under different working conditions of the power system (400), wherein the theoretical urea supply amounts are used as input parameters 1 of the control system (300);
taking the NOx concentration meeting the emission requirement as a target value, and simultaneously, taking the time period T 1 In, the mean value of NOx detected by the second sensor (202) is compared with a target value of NOx as an input parameter 2 of the control system (300);
the power system (400) is operated during a time period T 2 The difference value of the urea supply quantity superposition of the power MAP is taken as an input parameter 3 of the control system (300);
the control system (300) calculates a set supply amount based on the input parameter 1, the input parameter 2, and the input parameter 3, and controls the urea supply amount of the supply system (100) by the obtained set supply amount.
6. The control method of the SCR closed-loop control device according to claim 5, wherein a real-time flow rate of urea supply is obtained from a detection value fed back from the flow sensor (101), and the real-time flow rate is compared with the set supply amount, and an output value of the control valve (102) is adjusted.
7. The control method of the SCR closed-loop control device according to claim 6, wherein the real-time flow rate and the set supply amount are adjusted as an input value of the control valve (102) by PID.
8. The control method of the SCR closed-loop control device according to claim 5, wherein the theoretical urea supply is obtained by: and calibrating initial urea supply amounts under different working conditions through theoretical calculation or bench test to form a MAP of power and urea supply amounts.
9. The control method of an SCR closed-loop control device according to claim 5, wherein T 1 ＝kT 2 Wherein k is a positive integer.
10. The control method of the SCR closed-loop control device according to claim 9, wherein k is 1.ltoreq.15.
11. The control method of the SCR closed-loop control device according to claim 5, wherein the set supply amount is calculated by:
Q＝Q 1 +Q 2 +Q 3
Q 1 ＝f(P)
Q 3 ＝Q nT2 -Q (n-1)T2 ；
wherein Q is a set supply amount, Q 1 To the theoretical urea supply quantity, Q 2 To correct the urea supply, P is the power of the power system, Q 3 Is T 2 The difference value of the urea supply quantity superposition of the power MAP in the time period is N, wherein N is the absolute value of the difference value of the NOx concentration mean value and the NOx target value, N 1 ～N 3 Calculating a domain parameter, k, for NOx bias 1 And k 2 To adjust the ratio parameters; b 1 And b 2 To adjust the amplitude parameter, T 1 And T 2 For correcting the time parameter, Q nT2 Is the nth T 2 Time-dependent power MAP urea supply, Q (n-1)T2 Is the (n-1) th T 2 The power MAP urea supply amount corresponds to time.
12. According toThe control method of an SCR closed-loop control apparatus according to claim 11, wherein the period is 0 to T 1 Time, Q 1 And Q 2 Calculated as follows:
at 0 to T 1 Time period, Q 1 The real-time measurement power P value is calculated and is between 0 and T 1 Time varies over time over a period of time; q (Q) 2 Calculated at 0 time and 0 to T 1 The time period is kept unchanged;
at T 2 ～T 1 Time period, Q 1 Calculating the power P value measured in real time, and calculating the power P value at T 2 ～T 1 Time varies over time over a period of time; q (Q) 2 Taking T 1 Calculated at the moment, at T 2 ～T 1 Remains unchanged for a period of time.
13. The control method of the SCR closed-loop control apparatus according to claim 11,
wherein P is the power of the power system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310724538.6A CN116838458A (en) | 2023-06-16 | 2023-06-16 | SCR closed-loop control device and control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310724538.6A CN116838458A (en) | 2023-06-16 | 2023-06-16 | SCR closed-loop control device and control method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116838458A true CN116838458A (en) | 2023-10-03 |
Family
ID=88160885
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310724538.6A Pending CN116838458A (en) | 2023-06-16 | 2023-06-16 | SCR closed-loop control device and control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116838458A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117554302A (en) * | 2024-01-09 | 2024-02-13 | 杉木(深圳)生物科技有限公司 | Liquid detection method, device, equipment and storage medium |
-
2023
- 2023-06-16 CN CN202310724538.6A patent/CN116838458A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117554302A (en) * | 2024-01-09 | 2024-02-13 | 杉木(深圳)生物科技有限公司 | Liquid detection method, device, equipment and storage medium |
| CN117554302B (en) * | 2024-01-09 | 2024-04-02 | 杉木(深圳)生物科技有限公司 | Liquid detection method, device, equipment and storage medium |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105797576B (en) | Denitration ammonia injection control method for coal-fired unit | |
| CN107561941A (en) | A kind of full working scope qualified discharge control method of fired power generating unit denitrating system | |
| CN104722203B (en) | A kind of SCR denitration control system of flue gas of heating furnace and method | |
| US9779218B2 (en) | Method for model-based determination of a temperature distribution of an exhaust gas post-treatment unit | |
| KR101183057B1 (en) | Method for controlling injection of reducing agent in exhaust gas from a combustion engine | |
| CN116838458A (en) | SCR closed-loop control device and control method | |
| CN105739302B (en) | A kind of control method of the SCR denitration system based on analysis of sensitive factors | |
| JPH0342930B2 (en) | ||
| CN102759931B (en) | The control method of denitrating flue gas and device | |
| US6422005B2 (en) | Process and apparatus for the catalytic elimination of a pollutant from the exhaust gas from a combustion installation | |
| CN107448266A (en) | The automatic adding method of marine exhaust denitration urea and its device | |
| CN109339912B (en) | Method and device suitable for controlling nitrogen oxides of high-power diesel engine | |
| CN101842148A (en) | Adaptive control system for reagent distribution control in scr reactors | |
| EP0263183B1 (en) | NH3-Injection controller | |
| CN102900502B (en) | Oxygen sensor-based urea jet control device for diesel and control method for jet control device | |
| CN110501901A (en) | The SCR spray ammonia required based on the accurate denitration of full load adjusts the method optimized | |
| CN112221347A (en) | Accurate ammonia injection control method for SCR denitration system | |
| EP0996816A1 (en) | Engine fuel control system and method | |
| WO2015115978A1 (en) | Method and system at supply of additive to an exhaust gas stream | |
| CA3012103A1 (en) | Engine control system | |
| CN112370964A (en) | Method and system for improving comprehensive performance of SCR system of coal-fired power plant boiler | |
| JP4668852B2 (en) | Denitration equipment for combustion equipment | |
| CN109794150B (en) | Flue gas denitration control method and system for CFB boiler with external bed | |
| SE543014C2 (en) | Exhaust gas aftertreatment system | |
| JPH02204614A (en) | Method for eliminating nitrogen oxide in exhaust gas of diesel engine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |