KR20150062676A - Apparatus and Method for Urea Provision Control in Selective Catalytic Reduction System - Google Patents

Abstract

The present invention relates to an apparatus and a method for urea injection control in a selective catalytic reduction (SCR) system. According to the present invention, an apparatus for urea injection control in the SCR system comprises: a distribution module pumping urea applied as an aqueous solution from a tank in accordance with a control of a control module to be pressurized and authorized to an input module; an input module controlling an amount of inputted urea authorized to an injector in accordance with the control of the control module; a sensor detecting an amount of nitrogen oxide contained in an exhaust gas discharged from a reactor for a related detection signal to be authorized to the control module; and the control module controlling the input module.

Description

Technical Field [0001] The present invention relates to an apparatus and a method for controlling urea supply in an SCR system,

[0001] The present invention relates to an SCR (Selective Catalytic Reduction) system for processing exhaust gas discharged from a diesel engine installed in a ship or the like. In particular, a Urea is injected into an exhaust gas flowing into a reactor in an SCR system, The supply amount of urea is determined based on the amount of nitrogen oxides discharged from the reactor, and the amount of input urea determined by reflecting the engine load is injected to efficiently remove nitrogen oxides. Apparatus and method.

Nitrogen oxides and sulfur oxides among exhaust gases emitted from diesel engines commonly used in ships are representative air pollutants subject to emission regulation from the International Maritime Organization (IMO), which is a member of the United Nations (UN).

Nitrogen oxides refer to NO, NO2, NO3, N2O, N2O3, N2O4 and N2O5, but most nitrogen oxides are NO and NO2. Sulfur oxides are mainly SO2 in which sulfur components contained in fuels such as coal and petroleum are oxidized in the combustion process.

Nitrogen oxides are generated by the reaction of Nitrogen in the combustion process with thermal NOx generated by the reaction of nitrogen and oxygen in the air in the high temperature region, Prompt NOx generated by the reaction of hydrocarbons generated from the fuel with nitrogen in the air, Fueled NOx.

SCR systems have been used to remove nitrogen oxides generated by the combustion reaction of fossil fuels. In the SCR system, as shown in Equations (1) and (2), the nitrogen oxide of the exhaust gas is converted into nitrogen and water by a catalyst provided in the reactor and removed by injecting urea into the exhaust gas flowing into the reactor .

4NO + 4NH3 + O2 - > 4N2 + 6H2O (Formula 1)

6NO2 + 8NH3 - > 7N2 + 12H2O (Formula 2)

In the conventional SCR system, when the urea is injected into the exhaust gas flowing into the reactor, the urea in the form of an aqueous solution stored in the tank is atomized by the urea supply device, and the predetermined amount is continuously injected.

Such a urea supply device injects urea in the form of aqueous solution stored in the tank into the exhaust gas by continuously supplying a predetermined amount of the urea to the exhaust gas. Since the urea is supplied in a certain amount irrespective of the amount of nitrogen oxide introduced into the reactor, If the amount of nitrogen oxides present varies, the nitrogen oxide can not be completely removed due to the fact that the reactor does not receive the corresponding urea.

DISCLOSURE Technical Problem The present invention has been proposed in order to solve the problems of the prior art as described above. In the SCR system, when the urea is injected into the exhaust gas flowing into the reactor and the nitrogen oxide of the exhaust gas is removed by the reactor, The amount of injected urea is determined based on the amount of injected urea based on the amount of injected urea, and the amount of injected urea determined by reflecting the engine load is injected to sufficiently supply the urea necessary for removing the nitrogen oxide in the reactor, thereby efficiently removing nitrogen oxides using the urea And a method of controlling the urea supply of the SCR system.

In order to achieve the above object, there is provided an apparatus for regulating the supply of urea in an SCR system, comprising: a distribution module for pumping and pressurizing urea applied in the form of an aqueous solution from a tank under the control of a control module, The urea supplied from the distribution module is applied to the injector together with the compressed air to atomize the urea by the injector and inject the urea into the exhaust gas flowing into the reactor. The control module controls the amount of urea supplied to the injector ; A sensor for detecting the amount of nitrogen oxide contained in the exhaust gas discharged from the reactor and applying a corresponding detection signal to the control module; Wherein the control unit controls the distribution module and the input module so that the urea is introduced into the exhaust gas flowing into the reactor, the amount of nitrogen oxide detected based on the detection signal applied from the sensor is detected, and based on the amount of nitrogen oxide, And controlling the input module so as to adjust the amount of the urea to be supplied and to input the determined urea amount.

According to the urea supply control device of the SCR system according to the present invention, when the amount of supplied urea is determined on the basis of the amount of nitrogen oxides, the control module calculates the amount of urea supplied to the engine by reflecting the engine load according to the engine load signal applied from the engine .

According to the urea supply controller of the SCR system according to the present invention, the distribution module includes: a pump for pumping and applying pressure to the charging module, the urea being supplied from a tank under the control of the control module; And a plurality of valves for manually opening and closing the urea supply system via the pump.

According to another aspect of the present invention, there is provided a control apparatus for an urea supply control system, comprising: a control module for controlling an amount of urea supplied to the injector from the distribution module under the control of the control module; A flow meter for detecting the amount of urea applied to the injector from the control valve and notifying the control module of the detected urea amount; A plurality of valves for manually opening and closing the urea supply system via the control valve and the flow meter; And a plurality of valves for manually opening and closing the compressed air supply system applied to the injector.

According to another aspect of the present invention, there is provided an apparatus for controlling urea supply in an SCR system, wherein the control module controls the supply module and the supply module to supply urea, A microcomputer for performing a process; A memory for storing the urea supply control program and providing the microcontroller with the urea supply control program according to the control of the microcomputer; A display unit for displaying various data generated in the urea supply adjusting process under the control of the microcomputer; An operation unit for inputting various data and commands for controlling the urea supply by manual operation to the microcomputer; A first matching unit for matching the nitrogen oxide amount detection signal from the sensor so as to be processable by the microcomputer; A second matching unit for matching the control signal applied from the microcomputer so as to be usable in the distribution module; A third matching unit for matching the control signal applied from the microcomputer so as to be usable in the input module; A fourth matching section for matching the engine load signal applied from the engine so that the engine load signal can be processed by the microcomputer; And a fifth matching section for matching the input urea amount detection signal applied from the input module so as to be processable by the microcomputer.

According to the present invention, the microcomputer can determine the amount of nitrogen oxides discharged from the reactor based on the detection signal applied from the sensor through the first matching unit, And the amount of injected urea is determined by reflecting the engine load according to the engine load signal applied through the fourth matching portion.

In addition, according to the urea supply control device of the SCR system according to the present invention, the microcomputer outputs a control signal to the input module through the third matching part to control the control valve of the input module to inject the determined amount of the input urea into the exhaust gas The control valve of the charging module is controlled so as to inject the determined urea amount while confirming the amount of urea supplied to the injector based on the urea amount detection signal applied through the fifth matching part from the flow meter of the charging module.

According to another aspect of the present invention, there is provided a method for controlling the supply of urea in an SCR system, comprising the steps of: detecting a nitrogen oxide amount detected by a sensor installed at a discharge port of a reactor; Determining an amount of oxide; Determining an amount of injected urea based on the amount of nitrogen oxides detected by the control module, and determining an amount of injected urea reflecting an engine load; And the control module controls the control valve of the charging module to inject the determined amount of urea into the exhaust gas.

According to the method of controlling the urea supply of the SCR system according to the present invention, the control module inputs the determined urea amount while confirming the amount of the urea supplied to the injector based on the detection signal of the supplied urea supplied from the flow meter of the injection module And controlling the control valve of the charging module.

According to the present invention, when the urea is injected into the exhaust gas flowing into the reactor in the SCR system and the nitrogen oxide of the exhaust gas is removed by the reactor, the amount of the injected urea is determined on the basis of the amount of nitrogen oxide unreacted from the reactor By injecting the amount of the injected urea determined in accordance with the engine load, the reactor receives a sufficient supply of the urea required for the removal of the nitrogen oxide, thereby efficiently removing the nitrogen oxide using the urea.

1 is a diagram illustrating an apparatus for controlling urea supply in an SCR system according to the present invention.
2 is a diagram illustrating a distribution module applied to the present invention.
3 is a diagram illustrating an input module applied to the present invention.
4 is a diagram illustrating a control module applied to the present invention.
5 is a diagram illustrating a process of controlling urea supply in an SCR system according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Although the present invention has been described with reference to the embodiments shown in the drawings, it is to be understood that the present invention is not limited to the technical spirit and essential structure and operation of the present invention.

In the SCR system, when the urea is injected into the exhaust gas flowing into the reactor and the nitrogen oxide of the exhaust gas is removed by the reactor, the amount of injected urea is determined on the basis of the amount of nitrogen oxides unreacted and discharged from the reactor The amount of urea injected is determined by reflecting the engine load, and the determined amount of urea is injected into the exhaust gas flowing into the reactor to sufficiently supply the urea necessary for removing nitrogen oxides in the reactor, thereby efficiently removing nitrogen oxides .

1, the urea supply control device of the SCR system according to the present invention includes a tank 110, a distribution module 120, an input module 130, a control module 140, (150).

The tank 110 stores urea in the form of an aqueous solution and applies the urea to the distribution module 120 side. The distribution module 120 pumps and applies the urea applied from the tank 110 to the charging module 130.

The injection module 130 atomizes the urea by the injector 135 by applying the urea which is pressurized and applied from the distribution module 120 together with the compressed air to the injector 135, Gas.

By injecting urea into the exhaust gas flowing into the reactor 200 from the diesel engine, the nitrogen oxide of the exhaust gas is converted into nitrogen and water by the catalyst provided in the reactor 200 and is removed The process of converting nitrogen oxides into nitrogen and water to remove them is well known and a detailed description thereof will be omitted).

The sensor 150 detects the amount of untreated nitrogen oxides contained in the exhaust gas discharged from the reactor 200 and applies a corresponding detection signal to the control module 140. The control module 140 controls the distribution module 120 and the charging module 130 to inject urea into the exhaust gas flowing into the reactor 200. The control module 140 controls the supply of the nitrogen detected based on the detection signal applied from the sensor 150 Determines the amount of urea to be introduced based on the amount of nitrogen oxides, and controls the input module 130 to input the determined amount of urea. In addition, the control module 140 determines the amount of urea to be injected in consideration of the engine load according to the engine load signal applied from the engine in determining the amount of urea to be introduced.

The rationing module 120 includes a pump for pumping and pressurizing the urea supplied to the input module 130. The rationing module 120 drives the pump under the control of the control module 140 to pressurize the urea and apply do.

The injection module 130 applies the urea applied from the distribution module 120 to the injector 135 together with the compressed air to atomize the urea by the injector 135 and inject it into the exhaust gas flowing into the reactor 200 The control module 140 controls the amount of urea to be supplied.

The distribution module 120 includes a plurality of valves V11 and V12 and a pump P as shown in FIG. The pump P is driven in accordance with the control signal 1 applied from the control module 140 to pressurize the urea in the form of an aqueous solution flowing from the tank 110 through the valve V11 and supply the urea in the form of aqueous solution through the valve V12 . The valves V11 and V12 are manually operated to open and close the urea supply piping. The valve V11 manually opens and closes the urea inflow path from the tank 110 and the valve V12 opens and closes the valves V11 and V11. The urea inlet path applied via the pump P is manually opened and closed. The valves V11 and V12 may be useful for maintenance work on the urea supply system.

The input module 130 includes a plurality of valves V21 to V25, a control valve CV, and a flow meter (FM) as illustrated in FIG. The control valve CV regulates the amount of urea in accordance with the control signal 2 applied from the control module 140 and applies the urea amount to the injector 135 to control the amount of urea introduced into the exhaust gas in accordance with the control of the control module 140 . The flow meter FM detects the amount of urea injected into the injector 135 and applies a corresponding detection signal to the control module 140 to notify the control module 140 of the amount of the urea supplied to the control module 140, Controls the control valve (CV) while checking the amount of the urea injected into the injector (135), thereby controlling the amount of injected urea.

The valves V21 to V23 are manually operated to open and close the urea supply pipe. The valve V21 manually opens and closes the urea inflow path applied from the distribution module 120. The valve V22 opens and closes the valve V21, And the control valve CV, and the valve V23 manually opens and closes the urea inflow path via the flow meter FM. In addition, the valves V24 and V25 are manually operated to open and close the compressed air supply pipe, the valve V24 manually opens and closes the compressed air inflow path, and the valve V25 opens and closes the compressed air supplied through the valve V25 Open and close the air inlet manually. Such valves V21 to V25 can be usefully used in maintenance work for the urea supply system and the compressed air supply system. The compressed air flowing in via the valves V24 and V25 is supplied to the valve V21 via the valve V21, the control valve CV, the valve V22, the flow meter FM and the valve V23, And injected into the injector 135 to atomize the urea and inject it into the exhaust gas.

The control module 140 presses the urea by the distribution module 120 and applies it to the charging module 130 to allow the charging module 130 to atomize the urea through the injector 135 and into the exhaust gas, The amount of nitrogen oxide that is untreated and discharged from the reactor 200 based on the detection signal applied from the engine 150 is determined and the amount of urea to be supplied is determined based on the amount of the nitrogen oxide, The amount of urea to be injected is determined in accordance with the engine load. The control module 140 controls the control valve CV of the input module 130 so as to input the determined urea amount while confirming the amount of the urea injected into the injector 135 through the flowmeter FM, The amount of urea fed to the injector 135 by the valve CV is adjusted to control the amount of urea injected into the exhaust gas flowing into the reactor 200. Accordingly, the reactor 200 is supplied with a sufficient amount of urea corresponding to the amount of nitrogen oxides, thereby efficiently removing the nitrogen oxides of the exhaust gas.

That is, while the control module 140 is performing the process of removing the nitrogen oxide of the exhaust gas by the reactor 200 by injecting the urea into the exhaust gas flowing into the reactor 200, The amount of nitrogen oxide is determined through the sensor 150, the amount of charged urea is determined based on the amount of nitrogen oxides, the amount of charged urea is determined by reflecting the engine load, and the input module 130 is controlled, The amount of urea corresponding to the amount of nitrogen oxides is supplied to the reactor 200 to efficiently remove the nitrogen oxides of the exhaust gas.

 4, the control module 140 includes a microcomputer 141, a memory 142, a display section 143, an operation section 144, and matching sections 145-149. The microcomputer 141 controls the distribution module 120 and the input module 130 to proceed with the urea supply and performs all control processes for the urea supply control based on the urea supply control program.

The memory 142 stores a urea supply control program for controlling the urea supply and supplies the urea supply control program to the microcomputer 141, thereby causing the microcomputer 141 to perform all control processes for controlling the urea supply. The memory 142 stores various data necessary for the urea supply control under the control of the microcomputer 141 and provides the microcomputer 141 with the data.

Under the control of the microcomputer 141, the display unit 143 displays all data generated during the urea supply adjustment processing so that the data can be visually confirmed.

Then, the operation unit 144 inputs various data and commands for controlling the urea supply to the microcomputer 141 by manual operation of the operator.

The matching unit 145 matches the detection signal that detects the amount of nitrogen oxide applied from the sensor 150 so that it can be processed by the microcomputer 141, and applies the processed signal to the microcomputer 141. The matching unit 146 applies the control signal 1 applied from the microcomputer 141 to the distribution module 120 so that the control signal 1 usable in the pump P of the distribution module 120 is usable, The control signal CV2 applied from the microcomputer 141 to the control module CV of the input module 130 and applies the control signal to the input module 130. [ The matching unit 148 applies the engine load signal applied from the engine to the microcomputer 141 so that the microcomputer 141 can process the engine load signal and the matching unit 149 receives the engine load signal from the flow meter FM) to the microcomputer 141 so as to be processable by the microcomputer 141 and apply the processed signal to the microcomputer 141. [

The microcomputer 141 outputs the control signal 1 through the matching unit 146 in response to the command input through the operation unit 144 to drive the pump P of the distribution module 120 to feed the urea And controls the control valve CV of the charging module 130 by outputting the control signal 2 through the matching part 147 so that the charging module 130 causes the charging module 130 to supply the charging amount of the urea Is injected into the exhaust gas so that the reactor 200 proceeds with the process of removing the nitrogen oxide by using the urea.

The microcomputer 141 controls the operation of the reactor 200 based on the detection signal applied from the sensor 150 through the matching section 145. The process of removing the nitrogen oxide of the exhaust gas by the reactor 200, And determines the amount of injected urea based on the amount of nitrogen oxides and determines the amount of injected urea reflecting the engine load according to the engine load signal applied through the matching portion 148 .

The microcomputer 141 outputs the control signal 2 to the input module 130 through the matching unit 147 and controls the control valve CV of the input module 130 to input the determined amount of urea into the exhaust gas The control unit 150 controls the flow rate of the urea supplied to the injector 135 to the amount of the urea supplied to the injector 135 based on the input urea amount detection signal supplied from the flow meter FM through the matching unit 149, The injection module 130 adjusts the amount of urea fed to the injector 135 to control the amount of urea injected into the exhaust gas flowing into the reactor 200 by controlling the CV. Accordingly, the reactor 200 receives the amount of urea corresponding to the amount of nitrogen oxides, and efficiently removes the nitrogen oxides of the exhaust gas.

The urea supply control device of the SCR system according to the present invention having the functions as described above is capable of controlling the amount of urea injected into the exhaust gas flowing into the reactor 200 from the diesel engine of the ship And operates as shown in FIG.

First, the microcomputer 141 of the control module 140 receives the drive command through the operation unit 144 and outputs the control signal 1 through the matching unit 146 according to the drive command, The control module 140 controls the control valve CV of the input module 130 by outputting the control signal 2 through the matching part 147 while applying the urea to the input module 130 by driving the input module P, 130 to atomize the set amount of urea through the injector 135 into the exhaust gas (S100), and to proceed to the reactor 200 to remove the nitrogen oxide using the urea.

The microcomputer 141 of the control module 140 detects the amount of nitrogen oxides to be supplied from the sensor 150 installed at the outlet of the reactor 200 through the matching portion 145 during the injection of the urea into the exhaust gas, The amount of nitrogen oxides discharged from the reactor 200 is determined based on the signal (S200), the amount of charged urea is determined on the basis of the nitrogen oxide amount, and the amount of nitrogen oxide is determined based on the engine load The amount of charged urea is determined (S300).

The microcomputer 141 outputs the control signal 2 to the input module 130 through the matching unit 147 and controls the control valve CV of the input module 130 to input the determined amount of urea into the exhaust gas The control unit 150 controls the flow rate of the urea supplied to the injector 135 to the amount of the urea supplied to the injector 135 based on the input urea amount detection signal supplied from the flow meter FM through the matching unit 149, The injection module 130 adjusts the amount of urea sent to the injector 135 to control the amount of urea injected into the exhaust gas flowing into the reactor 200 in step S400.

The microcomputer 141 of the control module 140 checks whether a drive end command is input from the operation unit 144 in step S500. If the drive end command is not input, the microcomputer 141 returns to step S200 to perform the above- When the drive end command is inputted, the operation is terminated.

As described above, according to the present invention, when the urea is injected into the exhaust gas flowing into the reactor in the SCR system and the nitrogen oxide of the exhaust gas is removed by the reactor, the amount of nitrogen oxide The amount of urea to be injected is determined by reflecting the engine load and the amount of urea is determined by injecting the amount of urea into the exhaust gas flowing into the reactor so that the urea required for the removal of nitrogen oxide is sufficiently supplied to the reactor, The oxide can be efficiently removed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. And such changes are considered to be within the technical scope of the present invention.

The present invention can be applied to the case where urea is injected into the exhaust gas flowing into the reactor in the SCR system in order to purify the exhaust gas of the diesel engine. According to the present invention, when the urea is injected into the exhaust gas flowing into the reactor in the SCR system and the nitrogen oxide of the exhaust gas is removed by the reactor, the amount of urea added is determined based on the amount of nitrogen oxide that is unreacted and discharged from the reactor The amount of urea injected is determined in accordance with the engine load, and the determined amount of urea is injected into the exhaust gas flowing into the reactor to sufficiently supply the urea necessary for the removal of nitrogen oxide from the reactor, .

110; Tank 120; Distribution module
130; Input module 135; Injector
140; A control module 141; Microcomputer
142: memory 143; Display portion
144; Operating portions 145 to 149; The matching portion
150; Sensor P; Pump
FM; Flow meter CV; Control valve
V11, V12, V21 to V25; valve

Claims (9)

As a urea supply control device of an SCR (Selective Catalytic Reduction) system,
A distribution module for pumping and pressurizing the urea applied from the tank in the form of an aqueous solution under the control of the control module and applying the pressure to the input module;
The urea supplied from the distribution module is applied to the injector together with the compressed air to atomize the urea by the injector and inject the urea into the exhaust gas flowing into the reactor. The control module controls the amount of urea supplied to the injector ;
A sensor for detecting the amount of nitrogen oxide contained in the exhaust gas discharged from the reactor and applying a corresponding detection signal to the control module;
Wherein the control unit controls the distribution module and the input module so that the urea is introduced into the exhaust gas flowing into the reactor, the amount of nitrogen oxide detected based on the detection signal applied from the sensor is detected, and based on the amount of nitrogen oxide, And a control module for controlling the input module so as to adjust the amount of the urea and input the determined amount of urea.
The method according to claim 1,
Wherein the control module determines an amount of charged urea based on an engine load according to an engine load signal applied from an engine when determining an amount of charged urea based on the amount of nitrogen oxides.
The method according to claim 1,
The distribution module includes:
A pump for pumping and pressurizing the urea supplied from the tank according to the control of the control module and applying the pressure to the charging module;
And a plurality of valves for manually opening and closing the urea supply system via the pump.
The method according to claim 1,
The input module includes:
A control valve for controlling the amount of urea applied to the injector from the distribution module under the control of the control module;
A flow meter for detecting the amount of urea applied to the injector from the control valve and notifying the control module of the detected urea amount;
A plurality of valves for manually opening and closing the urea supply system via the control valve and the flow meter;
And a plurality of valves for manually opening and closing the compressed air supply system applied to the injector.
The method according to any one of claims 1 to 4,
The control module includes:
A microcomputer for controlling the distribution module and the input module to perform the urea supply control and performing all control processes for the urea supply control based on the urea supply control program;
A memory for storing the urea supply control program and providing the microcontroller with the urea supply control program according to the control of the microcomputer;
A display unit for displaying various data generated in the urea supply adjusting process under the control of the microcomputer;
An operation unit for inputting various data and commands for controlling the urea supply by manual operation to the microcomputer;
A first matching unit for matching the nitrogen oxide amount detection signal from the sensor so as to be processable by the microcomputer;
A second matching unit for matching the control signal applied from the microcomputer so as to be usable in the distribution module;
A third matching unit for matching the control signal applied from the microcomputer so as to be usable in the input module;
A fourth matching section for matching the engine load signal applied from the engine so that the engine load signal can be processed by the microcomputer;
And a fifth matching section for matching the input urea amount detection signal applied from the input module so as to be processable by the microcomputer.
The method of claim 5,
The microcomputer monitors the amount of nitrogen oxides discharged from the reactor based on a detection signal applied from the sensor through the first matching portion, determines the amount of charged urea based on the amount of nitrogen oxides, And the amount of injected urea is determined in accordance with the engine load depending on the signal.
The method of claim 6,
The microcomputer outputs a control signal to the input module through the third matching unit to control the control valve of the input module to input the determined amount of the input urea into the exhaust gas, And controls the control valve of the injection module so as to inject the determined urea amount while confirming the amount of the urea supplied to the injector based on the amount detection signal.
As a method for controlling urea supply in an SCR (Selective Catalytic Reduction) system,
The control module recognizing the amount of nitrogen oxide discharged from the reactor based on the nitrogen oxide amount detection signal detected by the sensor installed at the outlet of the reactor;
Determining an amount of injected urea based on the amount of nitrogen oxides detected by the control module, and determining an amount of injected urea reflecting an engine load;
And the control module controls the control valve of the input module to inject the determined amount of urea into the exhaust gas.
The method of claim 8,
The control module may further include a step of controlling the control valve of the charging module so as to inject the determined amount of urea while confirming the amount of the charged urea supplied to the injector based on the input urea amount detection signal applied from the flow meter of the charging module A method of controlling urea supply in an SCR system.

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