CN106799123B - A kind of control method and its control device of denitrification apparatus ammonia spraying amount - Google Patents

A kind of control method and its control device of denitrification apparatus ammonia spraying amount Download PDF

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CN106799123B
CN106799123B CN201710096426.5A CN201710096426A CN106799123B CN 106799123 B CN106799123 B CN 106799123B CN 201710096426 A CN201710096426 A CN 201710096426A CN 106799123 B CN106799123 B CN 106799123B
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mass flow
spray ammonia
value
computing module
module
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CN106799123A (en
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陈天光
吴文辉
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Shanghai Longking Environmental Protection Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/76—Gas phase processes, e.g. by using aerosols
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B12/00—Arrangements for controlling delivery; Arrangements for controlling the spray area
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D11/00—Control of flow ratio
    • G05D11/02—Controlling ratio of two or more flows of fluid or fluent material
    • G05D11/13—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means
    • G05D11/139—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means by measuring a value related to the quantity of the individual components and sensing at least one property of the mixture
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2062—Ammonia
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases

Abstract

The invention discloses the control methods and its control device of a kind of denitrification apparatus ammonia spraying amount, whether control method is adjusted spray ammonia mass flow by obtaining after practical denitration efficiency value is made comparisons with the difference of denitration efficiency setting value with the first preset value, if desired it adjusts, the difference of practical denitration efficiency value and denitration efficiency setting value input PI controller is then obtained into spray ammonia mass flow correction value, the spray ammonia mass flow correction value is added to obtain spray ammonia mass flow set point again with spray ammonia mass flow a reference value, it is inputted in PID controller after the spray ammonia mass flow set point and practical spray ammonia mass flow measurement are done difference, the control instruction control spray ammonia for obtaining spray ammonia regulating valve adjusts valve regulation spray ammonia mass flow.The control method of denitrification apparatus ammonia spraying amount of the invention is simple, adjusts precisely, can guarantee that denitration efficiency reaches desired value, amount of ammonia slip can also be made to be reduced to 3ppm or less.

Description

A kind of control method and its control device of denitrification apparatus ammonia spraying amount
Technical field
The present invention relates to the control method of denitration ammonia spraying amount control field more particularly to a kind of denitrification apparatus ammonia spraying amount and its Control device.
Background technique
With China's expanding economy, bring environmental pollution is also increasingly severe in energy-consuming.Wherein, atmosphere cigarette The destruction of dirt, acid rain, greenhouse effects and ozone layer has become the four big killers for endangering people's existence.Cigarette contained by coal-fired flue-gas The harmful substances such as dirt, sulfur dioxide, nitrogen oxides are to cause the main contributor of atmosphere pollution, acid rain and greenhouse effects.In China, The harmful substances such as sulfur dioxide, nitrogen oxides are mainly to be generated by coal-fired process.Currently, China has carried out on a large scale Flue gas desulfurization project, but the also large-scale development of denitrating flue gas.There is research data to show if continuing not reinforce in flue gas The improvement of nitrogen oxides, the total amount of nitrogen oxides and the specific gravity in atmosphere pollution will all rise, and be possible to replace dioxy Change sulphur as the major pollutants in atmosphere.
China's denitrating flue gas project is started late, and SCR gas denitrifying technology is widely used in coal-burning boiler cigarette at present Gas processing system is to remove environmentally harmful ingredient NO in flue gasx.Ammonia is sprayed into flue in the art, ammonia and cigarette NO in gasxNitrogen and water that chemical reaction generates environmental sound occur under certain condition.
Main chemical reactions formula is as follows:
4NO+4NH3+O2→4N2+6H2O
NO+NO2+2NH3→2N2+3H2O
NOxRemoving amount depend on ammonia be added amount, be expressed as NH3/NOxMolar ratio.The generation of chemical reaction needs To be arranged in flue in solid form by the effect of catalyst, catalyst, from the next flue gas in upstream and by ammonia spraying system The ammonia of addition is together even into denitrification apparatus reactor after ammonia-spraying grid and/or flow mixing device.Ammonia enters ammonia spray It needs to mix with the air that dilution air blasts before penetrating system, is diluted to the gas that ammonia density is 5% or so, is then sprayed through ammonia System enters flue and mixes with flue gas.Chemical reaction life occurs when passing through the hole of cellular catalyst for flue gas ammonia gas mixture At nitrogen and water, secondary pollution not will form not only, but also be also greatly reduced NOxDestruction to environment.
However, the denitration efficiency and spray ammonia flow for flue gas have close relationship, it, can be by if spray ammonia flow is too small Cause denitration efficiency low in lacking reaction raw materials；It is superfluous since ammonia is as reaction raw materials surplus if it is excessive to spray ammonia flow Ammonia can enter upstream device in cause security risk or be discharged into air to cause air pollution.Chinese invention application Numbers 201610235930.4, subject name is that a kind of coal unit denitration sprays ammonia control method and discloses a kind of SCR denitration process In about spray ammonia flow control method, pass through obtain outlet NOxConcentration measurement and with outlet NOxConcentration set point is subtracted each other Obtain NOxConcentration deviation, and by NOxConcentration deviation inputs main PID controller and obtains ammonia flow requirements, later to ammonia Demand value obtains ammonia flow setting value after being modified, obtain ammonia flow measured value and with ammonia flow setting value phase Subtract to obtain ammonia flow deviation, ammonia flow deviation is inputted in secondary PID controller obtain spray ammonia flow control instruction to Control actuator movement.
Foregoing invention is to have used NOxConcentration deviation directly inputs main PID controller and obtains ammonia flow requirements, by If the value of PID controller output also will be the same in inputting identical value to PID controller.But due to cigarette Throughput can change, if flue gas flow changes, identical NOxAmmonia flow requirements will corresponding to concentration deviation Generate change.So the scheme control spray ammonia flow of the disclosure of the invention is inaccurate, it often will lead to denitration efficiency and denitration be not achieved Setting value or amount of ammonia slip not can guarantee.
Therefore, applicant is dedicated to providing the control method and its control device of a kind of new denitrification apparatus ammonia spraying amount.
Summary of the invention
Desired denitration efficiency is not achieved the technical problem to be solved by the present invention is to denitration efficiency in the prior art and ammonia is escaped Ease amount not can guarantee.This method is for that in the control of control spray ammonia flow, can guarantee that denitration efficiency reaches the phase in denitrating technique Guarantee that amount of ammonia slip is less than 3ppm while the denitration efficiency of prestige.
In order to solve the above technical problems, the present invention provides a kind of control method of denitrification apparatus ammonia spraying amount, the control Method includes:
S10: NO in former flue gas before obtaining into the inlet of SCR reactorxThe outlet of concentration measurement and SCR reactor Locate NO in neat stressxConcentration measurement；
S20: pass through NO in the former flue gasxNO in concentration measurement and neat stressxConcentration measurement is calculated practical de- Nitre efficiency value；
S30: obtaining denitration efficiency setting value, and the denitration efficiency setting value and the practical denitration efficiency value are carried out phase Subtract；
S40: whether difference obtained in judgment step S30 is greater than the first preset value；
S50: if difference obtained in step S30 is not more than the first preset value, current spray ammonia mass flow is not adjusted；
S60: if difference obtained in step S30 is greater than the first preset value, difference obtained in step S30 is inputted into institute State the input terminal of PI controller, the PI controller output spray ammonia mass flow correction value；
S70: spray ammonia mass flow a reference value is obtained, by the spray ammonia mass flow correction value and the spray ammonia mass flow A reference value is added to obtain spray ammonia mass flow set point；
S80: obtaining practical spray ammonia mass flow measurement and carries out subtraction with the spray ammonia mass flow set point Subtract each other；
S90: the practical spray ammonia mass flow measurement and spray ammonia mass flow set point are carried out to the institute of subtraction The input terminal of the input PID controller of difference obtained in step S80 must be worth, the spray ammonia for obtaining the PID controller output is adjusted The control instruction of valve；
S100: the PID controller controls the spray ammonia by the control instruction that step S90 is obtained and adjusts valve regulation spray ammonia Mass flow.
Preferably, the first preset value described in the step S40 is 0~0.015.
Preferably, the flue gas that spray ammonia mass flow a reference value described in the step S70 passes through the former flue gas obtained Volumetric flow units are obtained multiplied by concentration measurement in the former flue gas multiplied by proportionality coefficient, and the proportionality coefficient is 0.75~ 1.00。
Preferably, denitration efficiency setting value described in the step S30 is determined by the number of plies of catalyst.
Preferably, when the catalyst number of plies is 2 layers, the denitration efficiency setting value is 80%；The catalyst number of plies When being 3 layers, the denitration efficiency setting value is 90%；When the catalyst number of plies is 4 layers, the denitration efficiency setting value is 95%.
The invention also discloses a kind of denitrification apparatus ammonia spraying amounts of control method for above-mentioned denitrification apparatus ammonia spraying amount Control device, comprising: first obtains module, and concentration measurement and SCR are anti-in the inlet original flue gas for obtaining SCR reactor Answer NO in the exit neat stress of devicexNO in original flue gas before concentration measurement is obtained into SCR reactorxConcentration measurement and SCR NO in the outlet neat stress of reactorxConcentration measurement；First computing module connect with the first acquisition module, passes through institute State in former flue gas that concentration measurement operation obtains practical denitration efficiency value in concentration measurement and neat stress；Second obtains module, For obtaining denitration efficiency setting value；Second computing module is connect with first computing module and the second acquisition module respectively, The difference between the denitration efficiency setting value and the practical denitration efficiency value is obtained for operation；Judgment module, and it is described Second computing module connection, for judging difference that second computing module obtains whether less than the first preset value.
The control device of denitrification apparatus ammonia spraying amount of the invention further includes PI controller, is connected with second computing module It connects, the difference for being obtained according to second computing module obtains spray ammonia mass flow correction value；Spray ammonia mass flow benchmark It is worth computing module, for obtaining spray ammonia mass flow a reference value；Third computing module, respectively with the spray ammonia mass flow benchmark Value computing module is connected with PI controller, is used for the spray ammonia mass flow correction value and the spray ammonia mass flow a reference value Addition obtains spray ammonia mass flow set point；Third obtains module, for obtaining practical spray ammonia mass flow measurement；4th fortune Module is calculated, module is obtained with the third computing module and third respectively and connect, for obtaining practical spray ammonia mass flow measurement Difference between value and the spray ammonia mass flow set point；PID controller is connect with the 4th computing module, is used for root The control instruction of spray ammonia regulating valve is obtained according to the difference that the 4th computing module exports；Adjustment module connects with the PID controller It connects, the control instruction for being exported according to the PID controller controls the spray ammonia and adjusts valve regulation spray ammonia flow.
Preferably.The spray ammonia mass flow a reference value computing module includes the 4th obtaining module, the 5th computing module, the Five obtain module and the 6th computing module；The 4th acquisition module is used to obtain the volume flow of the former flue gas；Described Five computing modules are connect with the first acquisition module and the 4th acquisition module respectively, are used for concentration measurement in the former flue gas With the mutually multiplied product of the volume flow of former flue gas；5th obtains module, for obtaining proportionality coefficient；6th computing module, with institute It states the 5th acquisition module to connect with the 5th computing module, for obtaining product obtained by the 5th computing module and the described 5th The proportionality coefficient of module is multiplied to obtain spray ammonia mass flow a reference value.
It is beneficial that following at least one may be implemented in the control method and its control device of denitrification apparatus ammonia spraying amount of the invention Effect.
1, control method disclosed by the invention due to can according to measurement actual condition under NOxConcentration, flue gas volume stream The data such as amount and ammonia mass flow measurement, first correction spray ammonia mass flow set point, further according to spray ammonia mass flow setting Value and ammonia mass flow measurement make difference, then pass through the control instruction of the precisely controlled spray ammonia regulating valve of PID controller, Again since PI controller has the effect of that elimination is remaining poor, the adjustment process for entirely spraying ammonia mass flow can be made more accurate and flat Surely.Control method in compared to the prior art, control method disclosed by the invention can make denitration efficiency reach denitration efficiency Amount of ammonia slip is controlled while setting value in 3ppm hereinafter, being effectively reduced after ammonia spraying amount control inaccurately causes excessive ammonia to enter Continuous device causes security risk or is discharged into air to pollute air.
2, the present invention is by the first preset value of setting, and by the difference of denitration efficiency setting value and practical denitration efficiency value and Compare, if no more than setting difference if do not adjust current spray ammonia mass flow, denitration efficiency setting value can be worked as in this way Spray ammonia mass flow is not adjusted when with the difference of practical denitration efficiency value in the range of certain allow, and then energy saving.
Detailed description of the invention
Invention is further described in detail with reference to the accompanying drawings and detailed description:
Fig. 1 is the flow diagram of the control method of denitrification apparatus ammonia spraying amount provided by the invention；
Fig. 2 is the structural schematic diagram of the control device of denitrification apparatus ammonia spraying amount provided by the invention.
Drawing reference numeral explanation:
1- first obtains module；The first computing module of 2-；3- second obtains module；The second computing module of 4-；5-PI control Device；6- third computing module；7- the 4th obtains module；The 5th computing module of 8-；9- the 5th obtains module；The 6th operation mould of 10- Block；11- third obtains module；The 4th computing module of 12-；13-PID controller；14- adjustment module.
Specific embodiment
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with It obtains other drawings based on these drawings.
Embodiment one
In conjunction with shown in Fig. 1 and Fig. 2, the present embodiment one discloses a kind of control method of denitrification apparatus ammonia spraying amount, this implementation The board-like catalyst that uses is vanadium titanium tungsten catalyst in example, and main component includes titanium dioxide, vanadic anhydride, tungstic acid, And two layers of catalyst is set in the present invention.
S10: NO in former flue gas before being obtained by the first acquisition measurement of module 1 into SCR reactorxConcentration measurement is 355.1mg/Nm3With NO in the outlet neat stress of SCR reactorxConcentration measurement is 79.05mg/Nm3；
S20: NO in original flue gas obtained in module 1 is obtained by firstxNO in concentration measurement and neat stressxMeasurement of concetration It is 77.74% that practical denitration efficiency value, which is calculated, in value；
S30: obtaining module 3 to obtain denitration efficiency setting value by second is 80%, by denitration efficiency setting value and first The practical denitration efficiency value that the processing of computing module 2 obtains obtains difference after being subtracted each other be 2.26%；
S40: obtaining the first preset value is 1.2%, and whether the gained difference in judgment step S30 is greater than the first preset value；
S50: judgement obtains the difference in step S30 and is greater than the first preset value, by the difference input PI control in step S30 The input terminal of device 5, by the proportional integration operation of PI controller 5, output spray ammonia mass flow correction value；
S60: being measured by the 4th acquisition module 7 and obtaining the volume flow of former flue gas is 202 × 104Nm3/h；
S70: by NO in the former flue gas obtained in the volume flow of the former flue gas obtained in step S60 and step S10xConcentration Measured value is multiplied to obtain product in the 5th computing module 8 to be 717.3kg/h；
S80: obtaining module 9 to obtain proportionality coefficient by the 5th is 0.8mol/mol, and wherein proportionality coefficient is denitration reaction Middle NH3/NOxMolar ratio；
S90: by the product being calculated in the proportionality coefficient obtained in step S80 and step S70 in the 6th computing module It is multiplied in 10 and obtains spray ammonia mass flow a reference value as 282.76kg/h；
S100: by spray ammonia mass flow obtained in spray ammonia mass flow correction value obtained in step S50 and step S90 A reference value must spray ammonia mass flow set point after being added in third computing module 6；
S110: obtaining the measurement of module 11 to obtain practical spray ammonia mass flow measurement by third is 220.0kg/h；
S120: ammonia matter will actually be sprayed obtained in spray ammonia mass flow set point and step S110 obtained in step S100 Measuring mass flow value carries out subtraction and obtains difference；
S130: the input terminal of the input PID controller 13 of difference obtained in step S120 compares by PID controller 13 The control instruction of example integral differential operation output spray ammonia regulating valve；
S140: the control instruction control input adjustment module 14 of spray ammonia regulating valve, adjustment module 14 adjust spray ammonia quality stream Amount.
The present embodiment adjust process it is basic after denitration pin rate be 79.6%, amount of ammonia slip 2.62ppm, compared to Spray ammonia flow control method in the prior art, the denitration efficiency of this method basically reach denitration efficiency setting value, the benefit of ammonia With rate it is higher, have high economic benefit and amount of ammonia slip be less than 3ppm, follow-up equipment is not impacted.
Embodiment two to 12
Table 1 be obtained according to the method in embodiment one 11 specific embodiments, specific test parameters and result see Table 1.
Table 1
From table 1 it follows that denitration efficiency obtains after the method in one has adjusted ammonia spraying amount through this embodiment It is effectively ensured, and amount of ammonia slip control is in 3ppm or less.
Embodiment 13
As shown in Fig. 2, present embodiment discloses a kind of control device of denitrification apparatus ammonia spraying amount, which includes: First obtains module 1, NO in the inlet original flue gas for obtaining SCR reactorxThe outlet of concentration measurement and SCR reactor Locate NO in neat stressxConcentration measurement；First computing module 2 connect with the first acquisition module 1, passes through NO in former flue gasxConcentration NO in measured value and neat stressxConcentration measurement operation obtains practical denitration efficiency value；Second obtains module 3, de- for obtaining Nitre efficiency setting value；Second computing module 4 connect with the first computing module 2 and the second acquisition module 3 respectively, obtains for operation Difference between denitration efficiency setting value and practical denitration efficiency value；Judgment module connect with the second computing module 4, is used for Judge difference that the second computing module 4 obtains whether less than the first preset value；PI controller 5 is connect with the second computing module 4, Difference for being obtained according to the second computing module 4 obtains spray ammonia mass flow correction value；Spray a reference value operation of ammonia mass flow Module, for obtaining spray ammonia mass flow a reference value.
The control device of denitrification apparatus ammonia spraying amount in the present embodiment further includes third computing module 6, respectively with spray ammonia matter It measures Flow datum value computing module and PI controller 5 connects, for ammonia mass flow correction value and spray ammonia mass flow base will to be sprayed Quasi- value addition obtains spray ammonia mass flow set point；Third obtains module 11, for obtaining practical spray ammonia mass flow measurement； 4th computing module 12 obtains module 11 with third computing module 6 and third respectively and connect, for obtaining practical spray ammonia quality stream Difference between measurement and spray ammonia mass flow set point；PID controller 13 connect with the 4th computing module 12, is used for The control instruction of spray ammonia regulating valve is obtained according to the difference that the 4th computing module 12 exports；Adjustment module 14, with PID controller 13 Connection, the aperture of the control instruction control spray ammonia regulating valve for being exported according to PID controller 13, and then adjust spray ammonia flow.
Wherein, spray ammonia mass flow a reference value computing module is obtained including the 4th acquisition module 7, the 5th computing module the 8, the 5th Modulus block 9 and the 6th computing module 10；4th acquisition module 7 is used to obtain the volume flow of former flue gas；5th computing module 8, It connect, is used for NO in former flue gas with the first acquisition module 1 and the 4th acquisition module 7 respectivelyxConcentration measurement and former flue gas The mutually multiplied product of volume flow；5th obtains module 9, for obtaining proportionality coefficient；6th computing module 10 obtains mould with the 5th Block 9 and the connection of the 5th computing module 8, the proportionality coefficient phase for 8 gained product of the 5th computing module to be obtained module 9 with the 5th It is multiplied to arrive spray ammonia mass flow a reference value.
In the present embodiment, the second computing module 4 and the 4th computing module are subtracter, and third computing module 6 is adder, 5th computing module 8 and the 6th computing module 10 are multiplier, and adjustment module 14 is spray ammonia regulating valve.
Comparative example one
Comparative example one uses the Chinese invention application number 201610235930.4 of the prior art, and subject name is a kind of combustion Ammonia control method is sprayed in coal unit denitration, is used identical experimental condition and test parameters with embodiment one, is provided with two layers of catalysis Agent, the outlet nitrous oxides concentration measured value for first obtaining SCR reactor is 79.32mg/Nm3With the outlet nitrogen oxygen of SCR reactor Compound concentration set point is 76mg/Nm3, and subtract each other to obtain nitrous oxides concentration deviation to be 3.32mg/Nm3, above-mentioned difference is defeated It becomes owner of and obtains ammonia flow requirements in PID controller；Obtain SCR reactor inlet nitrogen oxides concentration measurement be 356.0mg/Nm3It is 1.01 × 104Nm with boiler smoke measure of oxygen content value3/ h, with the entrance nitrogen oxygen of above-mentioned SCR reactor Compound concentration measurement and boiler smoke measure of oxygen content value are modified to obtain ammonia flow and set to ammonia flow demand respectively Definite value；Obtaining practical ammonia flow measured value is 215.3kg/h, and ammonia flow setting value and ammonia flow measured value are subtracted each other To ammonia flow deviation, output spray ammonia flow control instruction controls to adjust valve opening after being inputted secondary PID controller, through trying It tests to obtain denitration efficiency to be 76.6%, amount of ammonia slip is unable to control within 3ppm, has part unreacted ammonia to enter subsequent set It is standby to cause a hidden trouble.
The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art For member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications are also answered It is considered as protection scope of the present invention.

Claims (4)

1. a kind of control method of denitrification apparatus ammonia spraying amount characterized by comprising
S10: NO in the inlet original flue gas of SCR reactor is obtainedxIn the exit neat stress of concentration measurement and SCR reactor NOxConcentration measurement；
S20: pass through NO in the former flue gasxNO in concentration measurement and neat stressxPractical denitration effect is calculated in concentration measurement Rate value；
S30: denitration efficiency setting value is obtained, the denitration efficiency setting value and the practical denitration efficiency value are subtracted each other；
S40: whether difference obtained in judgment step S30 is greater than the first preset value；
S50: if difference obtained in step S30 is not more than the first preset value, current spray ammonia mass flow is not adjusted；
S60: if difference obtained in step S30 is greater than the first preset value, by the input PI control of difference obtained in step S30 The input terminal of device, the PI controller output spray ammonia mass flow correction value；
S70: spray ammonia mass flow a reference value is obtained, by the spray ammonia mass flow correction value and the spray ammonia mass flow benchmark Value addition obtains spray ammonia mass flow set point；
S80: it obtains practical spray ammonia mass flow measurement and is subtracted each other with the spray ammonia mass flow set point；
S90: by the input terminal of the input PID controller of difference obtained in step S80, the PID controller output spray ammonia is adjusted The control instruction of valve；
S100: the PID controller controls the spray ammonia by the control instruction that step S90 is obtained and adjusts valve regulation spray ammonia quality Flow；
First preset value described in the step S40 is 0~0.015；
Spray ammonia mass flow a reference value described in the step S70 passes through the flue gas volume flow value of former flue gas multiplied by former flue gas NOxConcentration measurement is obtained multiplied by proportionality coefficient, and the proportionality coefficient is 0.75~1.
2. the control method of denitrification apparatus ammonia spraying amount according to claim 1, it is characterised in that:
Denitration efficiency setting value described in the step S30 is determined by the number of plies of catalyst.
3. the control method of denitrification apparatus ammonia spraying amount according to claim 2, it is characterised in that:
When the catalyst number of plies is 2 layers, the denitration efficiency setting value is 80%；
When the catalyst number of plies is 3 layers, the denitration efficiency setting value is 90%；
When the catalyst number of plies is 4 layers, the denitration efficiency setting value is 95%.
4. a kind of denitration of control method for realizing denitrification apparatus ammonia spraying amount according to any one of claims 1 to 3 fills Set the control device of ammonia spraying amount characterized by comprising
First obtains module, NO in the inlet original flue gas for obtaining SCR reactorxConcentration measurement goes out with SCR reactor NO in neat stress at mouthfulxConcentration measurement；
First computing module is connect with the first acquisition module, passes through NO in the former flue gasxConcentration measurement and neat stress Middle NOxConcentration measurement operation obtains practical denitration efficiency value；
Second obtains module, for obtaining denitration efficiency setting value；
Second computing module is connect with first computing module and the second acquisition module respectively, is obtained for operation described de- Difference between nitre efficiency setting value and the practical denitration efficiency value；
Judgment module is connect with second computing module, and whether the difference for judging that second computing module obtains is small In the first preset value；
PI controller is connect with second computing module, and the difference for being obtained according to second computing module is sprayed Ammonia mass flow correction value；
Ammonia mass flow a reference value computing module is sprayed, for obtaining spray ammonia mass flow a reference value；
Third computing module is connect with the spray ammonia mass flow a reference value computing module and PI controller respectively, is used for institute Spray ammonia mass flow correction value is stated to be added to obtain spray ammonia mass flow set point with the spray ammonia mass flow a reference value；
Third obtains module, for obtaining practical spray ammonia mass flow measurement；
4th computing module obtains module with the third computing module and third respectively and connect, for obtaining practical spray ammonia matter Difference between measuring mass flow value and the spray ammonia mass flow set point；
PID controller is connect with the 4th computing module, and the difference for being exported according to the 4th computing module obtains spray ammonia tune Save the control instruction of valve；
Adjustment module is connect with the PID controller, described in the control instruction control for being exported according to the PID controller It sprays ammonia and adjusts valve regulation spray ammonia flow；
The spray ammonia mass flow a reference value computing module includes the 4th acquisition module, the 5th computing module, the 5th acquisition module With the 6th computing module；
The 4th acquisition module is used to obtain the volume flow of the former flue gas；
5th computing module, respectively with first acquisition module and the 4th acquisition module connect, for will it is described original flue gas in NOxThe mutually multiplied product of volume flow of concentration measurement and former flue gas；
5th obtains module, for obtaining proportionality coefficient；
6th computing module connect with the 5th acquisition module and the 5th computing module, is used for the 5th computing module Gained product is multiplied to obtain spray ammonia mass flow a reference value with the proportionality coefficient of the 5th acquisition module, and the proportionality coefficient is 0.75~1.
CN201710096426.5A 2017-02-22 2017-02-22 A kind of control method and its control device of denitrification apparatus ammonia spraying amount Active CN106799123B (en)

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