LU505199B1 - Automatic control process method for denitration in ammonia preparation from urea - Google Patents
Automatic control process method for denitration in ammonia preparation from urea Download PDFInfo
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- LU505199B1 LU505199B1 LU505199A LU505199A LU505199B1 LU 505199 B1 LU505199 B1 LU 505199B1 LU 505199 A LU505199 A LU 505199A LU 505199 A LU505199 A LU 505199A LU 505199 B1 LU505199 B1 LU 505199B1
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- module
- denitration
- electrically connected
- ammonia
- nox concentration
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 215
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 106
- 238000000034 method Methods 0.000 title claims abstract description 68
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 239000004202 carbamide Substances 0.000 title claims abstract description 41
- 230000008569 process Effects 0.000 title claims abstract description 33
- 238000002347 injection Methods 0.000 claims abstract description 79
- 239000007924 injection Substances 0.000 claims abstract description 79
- 239000003517 fume Substances 0.000 claims abstract description 35
- 239000007789 gas Substances 0.000 claims abstract description 24
- 238000001514 detection method Methods 0.000 claims abstract description 22
- 238000005259 measurement Methods 0.000 claims abstract description 17
- 238000006243 chemical reaction Methods 0.000 claims description 35
- 230000001105 regulatory effect Effects 0.000 claims description 27
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 20
- 238000000738 capillary electrophoresis-mass spectrometry Methods 0.000 claims description 17
- 238000010926 purge Methods 0.000 claims description 13
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 238000012937 correction Methods 0.000 claims description 6
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 claims description 4
- 238000012544 monitoring process Methods 0.000 claims description 3
- 230000008859 change Effects 0.000 abstract description 7
- 230000007062 hydrolysis Effects 0.000 abstract description 6
- 238000006460 hydrolysis reaction Methods 0.000 abstract description 6
- 238000005516 engineering process Methods 0.000 description 6
- 230000003068 static effect Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 206010024769 Local reaction Diseases 0.000 description 3
- 230000007774 longterm Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000011217 control strategy Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- -1 ammonia chlorine-ammonia hydrogen sulfide Chemical compound 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 239000002808 molecular sieve Substances 0.000 description 1
- 150000002927 oxygen compounds Chemical class 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 235000015096 spirit Nutrition 0.000 description 1
Classifications
-
- 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
- B01D53/30—Controlling by gas-analysis apparatus
-
- 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
- B01D53/346—Controlling the process
-
- 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
- B01D53/77—Liquid phase processes
- B01D53/79—Injecting reactants
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
-
- 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
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2067—Urea
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
- B01D2257/402—Dinitrogen oxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
- B01D2257/404—Nitrogen oxides other than dinitrogen oxide
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Inorganic Chemistry (AREA)
- Treating Waste Gases (AREA)
Abstract
The present invention discloses an automatic control process method for denitration in ammonia preparation from urea, and the method includes a control unit, specifically, the control unit includes a detection unit, a numerical setting unit and a NOX concentration measurement value judgment logic unit; ammonia injection denitration controllers are electrically connected to a data receiving module; and the NOX concentration measurement value judgment logic unit is electrically connected to a regulator control module. The method of the present invention may be extended to fume gas denitration regulation systems in other power plants or industries, especially for a denitration system for ammonia preparation from urea hydrolysis, dynamic regulation quality in a load change process may be obviously improved to save urea.
Description
AUTOMATIC CONTROL PROCESS METHOD FOR DENITRATION IN 0505199
AMMONIA PREPARATION FROM UREA
The present invention relates to the field of fume gas denitration, in particular to an automatic control process method for denitration in ammonia preparation from urea.
Fume gas denitration is a technology to remove nitrogen and oxygen compounds from fume gas using appropriate equipment, materials and processes, such as adsorption denitration technology with molecular sieve, activated carbon, silica gel, ion exchange resin and peat-alkali as materials, absorption denitration technology with alkali liquor, molten salt, sulfuric acid and magnesium hydroxide as materials, and selective catalytic reduction denitration technologies such as ammonia chlorine-ammonia hydrogen sulfide, and carbon monoxide.
At present, safety, environmental protection and energy conservation have higher requirements for fume gas denitration system in power plants, especially after ammonia is prepared from urea hydrolysis instead of liquid ammonia, product gas is ready to use, and higher requirements for automatic control quality of ammonia injection are proposed.
However, for an automatic denitration control process in existing ammonia preparation from urea, excessive ammonia injection of a regulator may cause more working medium waste and air preheater blockage, environmental protection fails to meet the standard due to insufficient ammonia injection, and a subsequent denitration efficiency cannot be guaranteed.
Therefore, an automatic control process method for denitration in ammonia preparation from urea is required to solve the above problems.
A main objective of the present invention is to provide an automatic control process method for denitration in ammonia preparation from urea, so as to effectively solve the problems in the background.
In order to achieve the above objective, the technical solution adopted by the present invention is as follows: an automatic control process method for denitration in ammonia preparation from urea, including a control unit, specifically, the control unit includes a detection unit, a numerical setting unit and a NOX concentration measurement value judgment logic unit; and the detection 905199 unit includes a NOX concentration sensor and a fume gas flow sensor, the detection unit is electrically connected to ammonia injection denitration controllers, the ammonia injection denitration controllers are electrically connected to a data receiving module, the data receiving module is electrically connected to a calculation module, and the calculation module is electrically connected to a compensation unit; and the numerical setting unit is electrically connected to a NOX concentration measurement value judgment logic unit; and the NOX concentration measurement value judgment logic unit is electrically connected to a deviation value and a fluctuation range, and is electrically connected to a regulator control module, and the regulator control module is electrically connected to an adjustment unit and a detection module.
Preferably, the ammonia injection denitration controllers include an ammonia injection denitration controller I, an ammonia injection denitration controller II and an ammonia injection denitration controller N, an output end of the detection unit is electrically connected to input ends of the ammonia injection denitration controllers, output ends of the ammonia injection denitration controllers are electrically connected to an input end of a data receiving module, an output end of the data receiving module is electrically connected to an input end of a calculation module, and an output end of the calculation module is electrically connected to an input end of the compensation unit.
Preferably, the calculation module includes an inlet NOX flow data detection module, the output end of the calculation module is electrically connected to input ends of a differential compensation module and a comparison module, an output end of the comparison module is electrically connected to an input end of a numerical setting unit and an input end of a dynamic correction module.
Preferably, the numerical setting unit includes a standard value setting module, and the standard value setting module includes a NOX concentration standard value, a fume gas flow standard value and a NOX flow standard value; and an output end of the numerical setting unit is electrically connected to an input end of a NOX concentration measurement value judgment logic unit.
Preferably, an output end of the NOX concentration measurement value judgment logic unit is electrically connected to input ends of the deviation value and the fluctuation range, a 905199 output end of the regulator control module is electrically connected to an input end of the detection module and an input end of the adjustment unit.
Preferably, the adjustment unit includes a CEMS regulating module and a nitrogen injection grid regulating module, and the CEMS regulating module includes a nominal time module, an automatic purging module and an interval time module.
Preferably, the nitrogen injection grid regulating module includes a hand valve opening monitoring module, output ends of the nitrogen injection grid regulating module and the CEMS regulating module are electrically connected to an input end of a current signal isolator, an output end of the current signal isolator is electrically connected to an input end of a DCS controller and an input end of a PLC controller, and an output end of the DCS controller is electrically connected to the input end of the PLC controller.
Preferably, the calculation module performs calculations, such as multiplying an inlet NOX concentration in a reaction zone by a fume gas flow to obtain an inlet NOX flow in the reaction zone, and then multiplying the inlet NOX flow by a molar ratio of ammonia nitrogen to obtain a required value of an ammonia injection flow.
Preferably, the fluctuation range and the deviation value are in cases that the fluctuation range of a measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet NOX concentration value in the reaction zone and a set value or the measured NOX concentration value in clean fume is greater than a certain value.
Beneficial effects
Compared with the prior art, the present invention provides an automatic control process method for denitration in ammonia preparation from urea, and the method has the following beneficial effects: 1. according to the automatic control process method for denitration in ammonia preparation from urea, intelligent prediction and automatic parameter changing technology is adopted to refine and optimize an automatic regulator for fume gas denitration, so that under working conditions of a severe load change of a unit, periodic purging of CEMS devices, a saturation of a urea hydrolysis system, working medium waste and air preheater blockage caused by excessive ammonia injection of the regulator, or an environmental protection failure caused by insufficient ammonia injection may be avoided, and a high adjustment quality and an ideal 202199 denitration efficiency may still be maintained, 2. according to the automatic control process method for denitration in ammonia preparation from urea, calculation logic for a change rate of an inlet NOX flow is added, and differential compensation is made for a static required value of an ammonia injection flow subjected to an original static calculation, and dynamic corrections of a range and a rate of the differential compensation are made according to the deviation between an outlet NOX concentration in the reaction zone and the set value, so that an optimal ammonia injection flow is obtained in the reaction zone, and the outlet NOX concentration may still reach the standard smoothly under severe working conditions; and the method may be extended to fume gas denitration regulation systems in other power plants or industries, especially for a denitration system for ammonia preparation from urea hydrolysis, dynamic regulation quality in a load change process may be obviously improved to save urea; 3. according to the automatic control process method for denitration in ammonia preparation from urea, judgment logic for a measured outlet NOX concentration value in the reaction zone is added, when the fluctuation range of the measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet
NOX concentration value in the reaction zone and a set value or a measured NOX concentration value in clean fume is greater than a certain value, an integral function of the regulator is automatically canceled to avoid a misoperation of an ammonia injection regulating valve, while when a duration that the fluctuation range of the measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet NOX concentration value in the reaction zone and a set value or a measured NOX concentration value in clean fume is greater than a certain value, is too long, and an outlet CEMS performs automatic purging, the measured NOX concentration value in the clean fume will be automatically used to replace the measured outlet NOX value in the local reaction zone and fed back to the regulator, so as to avoid long-term misoperation or operation refusal of the ammonia injection regulating valve, and the integral function of the regulator is automatically restored and the feedback signal sent to the regulator is switched back to the outlet NOX concentration value after the outlet NOX concentration is measured to be normal by logic judgment; and the method may be extended to fume gas denitration regulation systems in other power plants or industries, and especially fora 905199 system for ammonia preparation from urea instead of liquid ammonia, urea may be saved to a certain extent; and 4. according to the automatic control process method for denitration in ammonia 5 preparation from urea, existing automatic control systems for denitration and ammonia injection may be optimized, the automatic purging, the nominal time and the interval time may be reasonably adjusted, so as to prevent purging time of CEMS devices at the inlet and outlet of denitration from overlapping, thus ensuring authenticity of received parameters such as NOx and
O2 contents to the greatest extent; the ammonia injection of ammonia injection grid is optimized, the opening of hand valves of all ammonia inlet branches may be adjusted to adjust ammonia injection amounts in different zones and then achieve uniform ammonia injection, an ammonia injection control valve is overhauled, re-debugged and located to make the opening of valves on two sides consistent with flow characteristics as possible; functions are used in the distributed control system DCS to correct valve characteristics; and logic of a control system is optimized, specifically, the current signal isolator is used to introduce parameter measuring points automatically related to the ammonia injection into the PLC and the DCS at the same time, an automatic control of the ammonia injection is configured logically in the DCS, and then an automatic instruction of the regulating valve is sent back to the PLC for output, automatic operations related to denitration and ammonia injection, such as automatic switching, given value setting and flow offset, are still carried out in the original auxiliary screen, and a logical operation is only carried out in the DCS; and after control logic is introduced into the DCS, an automatic control strategy of the ammonia injection is optimized, and cascade loop control is still adopted for a main body after optimization.
FIG. 1 is a structural schematic diagram for a control unit of the present invention;
FIG. 2 is a structural schematic diagram for a compensation unit of the present invention;
FIG. 3 is a structural schematic diagram for a numerical setting unit of the present invention; and
FIG. 4 is a structural schematic diagram for an adjustment unit of the present invention.
In order to make the technical means, creative features, goals and effects of the present 905199 invention easy to understand, the present invention will be further elaborated with specific embodiments.
As shown in FIGs. 1-4, an automatic control process method for denitration in ammonia preparation from urea, including a control unit, specifically, the control unit includes a detection unit, a numerical setting unit and a NOX concentration measurement value judgment logic unit; the detection unit includes a NOX concentration sensor and a fume gas flow sensor, the detection unit is electrically connected to ammonia injection denitration controllers, the ammonia injection denitration controllers are electrically connected to a data receiving module, the data receiving module is electrically connected to a calculation module, and the calculation module is electrically connected to a compensation unit; the numerical setting unit is electrically connected to a NOX concentration measurement value judgment logic unit; the NOX concentration measurement value judgment logic unit is electrically connected to a deviation value and a fluctuation range, and is electrically connected to a regulator control module, and the regulator control module is electrically connected to an adjustment unit and a detection module; the ammonia injection denitration controller includes an ammonia injection denitration controller I, an ammonia injection denitration controller II and an ammonia injection denitration controller N, an output end of the detection unit is electrically connected to input ends of the ammonia injection denitration controllers, output ends of the ammonia injection denitration controllers are electrically connected to an input end of a data receiving module, an output end of the data receiving module is electrically connected to an input end of a calculation module, and an output end of the calculation module is electrically connected to an input end of the compensation unit; the calculation module includes an inlet NOX flow data detection module, and performs calculations, such as multiplying an inlet NOX concentration in a reaction zone by a fume gas flow to obtain an inlet NOX flow in the reaction zone, and then multiplying the inlet NOX flow by a molar ratio of ammonia nitrogen to obtain a required value of an ammonia injection flow, and the output end of the calculation module is electrically connected to input ends of a differential compensation module and a comparison module, and an output end of the comparison module is electrically connected to an input end of a numerical setting unit and an input end of a dynamic correction module; the numerical setting unit includes a standard value setting module, the standard value setting module includes a NOX concentration standard value 20°" 99 a fume gas flow standard value and a NOX flow standard value, and an output end of the numerical setting unit is electrically connected to an input end of a NOX concentration measurement value judgment logic unit; an output end of the NOX concentration measurement value judgment logic unit is electrically connected to input ends of the deviation value and the fluctuation range, specifically, the fluctuation range and the deviation value are in cases that the fluctuation range of a measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet NOX concentration value in the reaction zone and a set value or the measured NOX concentration value in clean fume is greater than a certain value, and an output end of the regulator control module is electrically connected to an input end of the detection module and an input end of the adjustment unit; the adjustment unit includes a CEMS regulating module and a nitrogen injection grid regulating module, and the
CEMS regulating module includes a nominal time module, an automatic purging module and an interval time module; and the nitrogen injection grid regulating module includes a hand valve opening monitoring module, output ends of the nitrogen injection grid regulating module and the
CEMS regulating module are electrically connected to an input end of a current signal isolator, an output end of the current signal isolator is electrically connected to an input end of a DCS controller and an input end of a PLC controller, and an output end of the DCS controller is electrically connected to the input end of the PLC controller.
According to the automatic control process method for denitration in ammonia preparation from urea, intelligent prediction and automatic parameter changing technology is adopted to refine and optimize an automatic regulator for fume gas denitration, so that under working conditions of a severe load change of a unit, periodic purging of CEMS devices, a saturation of a urea hydrolysis system, working medium waste and air preheater blockage caused by excessive ammonia injection of the regulator, or an environmental protection failure caused by insufficient ammonia injection may be avoided, and a high adjustment quality and an ideal denitration efficiency may still be maintained.
According to the automatic control process method for denitration in ammonia preparation from urea, calculation logic for a change rate of an inlet NOX flow is added, and differential compensation is made for a static required value of an ammonia injection flow subjected to an original static calculation, and dynamic corrections of a range and a rate of the differential 20> 00 compensation are made according to the deviation between an outlet NOX concentration in the reaction zone and the set value, so that an optimal ammonia injection flow is obtained in the reaction zone, and the outlet NOX concentration may still reach the standard smoothly under severe working conditions; and the method may be extended to fume gas denitration regulation systems in other power plants or industries, especially for a denitration system for ammonia preparation from urea hydrolysis, dynamic regulation quality in a load change process may be obviously improved to save urea.
According to the automatic control process method for denitration in ammonia preparation from urea, judgment logic for a measured outlet NOX concentration value in the reaction zone is added, when the fluctuation range of the measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet NOX concentration value in the reaction zone and a set value or a measured NOX concentration value in clean fume is greater than a certain value, an integral function of the regulator is automatically canceled to avoid a misoperation of an ammonia injection regulating valve, while when a duration that the fluctuation range of the measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet NOX concentration value in the reaction zone and a set value or a measured NOX concentration value in clean fume is greater than a certain value, is too long, and an outlet CEMS performs automatic purging, the measured NOX concentration value in the clean fume will be automatically used to replace the measured outlet NOX value in the local reaction zone and fed back to the regulator, so as to avoid long-term misoperation or operation refusal of the ammonia injection regulating valve, and the integral function of the regulator is automatically restored and the feedback signal sent to the regulator is switched back to the outlet NOX concentration value after the outlet NOX concentration is measured to be normal by logic judgment; and the method may be extended to fume gas denitration regulation systems in other power plants or industries, especially for a system for ammonia preparation from urea instead of liquid ammonia, urea may be saved to a certain extent.
According to the automatic control process method for denitration in ammonia preparation from urea, existing automatic control systems for denitration and ammonia injection may be optimized, the automatic purging, the nominal time and the interval time may be adjusted, so as to prevent purging time of CEMS devices at the inlet and outlet of denitration from overlapping, thus ensuring authenticity of received parameters such as NOx and O2 contents to the greatest extent; the ammonia injection of ammonia injection grid is optimized, the opening of hand valves of all ammonia inlet branches may be adjusted to adjust ammonia injection amounts in different zones and then achieve uniform ammonia injection, an ammonia injection control valve is overhauled, re-debugged and located to make the opening of valves on two sides consistent with flow characteristics as possible; functions are used in the distributed control system DCS to correct valve characteristics; and logic of a control system is optimized, specifically, the current signal isolator is used to introduce parameter measuring points automatically related to the ammonia injection into the PLC and the DCS at the same time, an automatic control of the ammonia injection is configured logically in the DCS, and then an automatic instruction of the regulating valve is sent back to the PLC for output, automatic operations related to denitration and ammonia injection, such as automatic switching, given value setting and flow offset, are still carried out in the original auxiliary screen, and a logical operation is only carried out in the DCS; and after control logic is introduced into the DCS, an automatic control strategy of the ammonia injection is optimized, and cascade loop control is still adopted for a main body after optimization.
It is noted that the present invention is an automatic control process method for denitration in ammonia preparation from urea, when the method is used, values of various standards are set, including standard value setting module, NOX concentration standard value and fume gas flow standard value; and before control, nominal time, purging and interval time of equipment are set through the CEMS regulating module, and valves of all pipelines are adjusted until achieving uniform ammonia injection.
The ammonia injection denitration controllers are installed according to actual situations, the NOX concentration sensor and the fume gas flow sensor are used to monitor and process data, the monitored data are calculated by the calculation module, specifically, multiplying an inlet
NOX concentration in a reaction zone by a fume gas flow to obtain an inlet NOX flow in the reaction zone, and then multiplying the inlet NOX flow by a molar ratio of ammonia nitrogen to obtain a required value of an ammonia injection flow; after calculation, the compensation unit will make differential compensation for a static required value of an ammonia injection flow 905199 subjected to an original static calculation, and make dynamic corrections of a range and a rate of the differential compensation according to the deviation between an outlet NOX concentration in the reaction zone and the set value, so that an optimal ammonia injection flow is obtained in the reaction zone, and the outlet NOX concentration may still reach the standard smoothly under severe working conditions.
The measured outlet NOX concentration value in the reaction zone is judged logically, and the NOX concentration judgment logic unit will monitor the value in real time, specifically, when the fluctuation range of the measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet NOX concentration value in the reaction zone and a set value or a measured NOX concentration value in clean fume is greater than a certain value, the NOX concentration judgment logic unit will send a signal to the regulator control module, so as to automatically cancel a integral function of the regulator and avoid a misoperation of an ammonia injection regulating valve, while when a duration that the fluctuation range of a measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet NOX concentration value in the reaction zone and a set value or a measured NOX concentration value in clean fume is greater than a certain value, is too long, and the outlet CEMS performs automatic purging, the measured
NOX concentration value in the clean fume will be automatically used to replace the measured outlet NOX value in the local reaction zone and fed back to the regulator, so as to avoid long-term misoperation or operation refusal of the ammonia injection regulating valve, and the integral function of the regulator is automatically restored and the feedback signal sent to the regulator is switched back to the outlet NOX concentration value after the outlet NOX concentration is measured to be normal by logic judgment.
The basic principles, main features and advantages of the present invention have been shown and described above. It is understood by those skilled in the art that the present invention is not limited by the above examples, and what is described in the above examples and descriptions only illustrates the principles of the present invention. Without departing from spirits and scopes of the present invention, there will be various changes and improvements in the present invention, and the changes and improvements fall within the protection scope of the
. . . . . . L1)505199 present invention.
The protection scope of the present invention is defined by the appende claims and their equivalents.
Claims (9)
1. An automatic control process method for denitration in ammonia preparation from urea, comprising a control unit, wherein the control unit comprises a detection unit, a numerical setting unit and a NOX concentration measurement value judgment logic unit; and the detection unit comprises a NOX concentration sensor and a fume gas flow sensor, the detection unit is electrically connected to ammonia injection denitration controllers, the ammonia injection denitration controllers are electrically connected to a data receiving module, the data receiving module is electrically connected to a calculation module, and the calculation module is electrically connected to a compensation unit; and the numerical setting unit is electrically connected to a NOX concentration measurement value judgment logic unit; and the NOX concentration measurement value judgment logic unit is electrically connected to a deviation value and a fluctuation range, and is electrically connected to a regulator control module, and the regulator control module is electrically connected to an adjustment unit and a detection module.
2. The automatic control process method for denitration in ammonia preparation from urea according to claim 1, wherein the ammonia injection denitration controllers comprise an ammonia injection denitration controller I, an ammonia injection denitration controller II and an ammonia injection denitration controller N, an output end of the detection unit is electrically connected to input ends of the ammonia injection denitration controllers, output ends of the ammonia injection denitration controllers are electrically connected to an input end of a data receiving module, an output end of the data receiving module is electrically connected to an input end of a calculation module, and an output end of the calculation module is electrically connected to an input end of the compensation unit.
3. The automatic control process method for denitration in ammonia preparation from urea according to claim 1, wherein the calculation module comprises an inlet NOX flow data detection module, the output end of the calculation module is electrically connected to input ends of a differential compensation module and a comparison module, an output end of the comparison module is electrically connected to an input end of a numerical setting unit and an input end of a dynamic correction module.
4. The automatic control process method for denitration in ammonia preparation from urea 905799 according to claim 1, wherein the numerical setting unit comprises a standard value setting module, and the standard value setting module comprises a NOX concentration standard value, a fume gas flow standard value and a NOX flow standard value; and an output end of the numerical setting unit is electrically connected to an input end of a NOX concentration measurement value judgment logic unit.
5. The automatic control process method for denitration in ammonia preparation from urea according to claim 1, wherein an output end of the NOX concentration measurement value judgment logic unit is electrically connected to input ends of the deviation value and the fluctuation range, an output end of the regulator control module is electrically connected to an input end of the detection module and an input end of the adjustment unit.
6. The automatic control process method for denitration in ammonia preparation from urea according to claim 1, wherein the adjustment unit comprises a CEMS regulating module and a nitrogen injection grid regulating module, and the CEMS regulating module comprises a nominal time module, an automatic purging module and an interval time module.
7. The automatic control process method for denitration in ammonia preparation from urea according to claim 6, wherein the nitrogen injection grid regulating module comprises a hand valve opening monitoring module, output ends of the nitrogen injection grid regulating module and the CEMS regulating module are electrically connected to an input end of a current signal isolator, an output end of the current signal isolator is electrically connected to an input end of a DCS controller and an input end of a PLC controller, and an output end of the DCS controller is electrically connected to the input end of the PLC controller.
8. The automatic control process method for denitration in ammonia preparation from urea according to claim 1, wherein the calculation module performs calculations of multiplying an inlet NOX concentration in a reaction zone by a fume gas flow to obtain an inlet NOX flow in the reaction zone, and then multiplying the inlet NOX flow by a molar ratio of ammonia nitrogen to obtain a required value of an ammonia injection flow.
9. The automatic control process method for denitration in ammonia preparation from urea according to claim 1, wherein the fluctuation range and the deviation value are in cases that the fluctuation range of a measured outlet NOX concentration value in the reaction zone is abnormally low, and the deviation between the measured outlet NOX concentration value in the 905199 reaction zone and a set value or a measured NOX concentration value in clean fume is greater than a certain value.
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| Application Number | Priority Date | Filing Date | Title |
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| LU505199A LU505199B1 (en) | 2023-09-28 | 2023-09-28 | Automatic control process method for denitration in ammonia preparation from urea |
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| Application Number | Priority Date | Filing Date | Title |
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| LU505199A LU505199B1 (en) | 2023-09-28 | 2023-09-28 | Automatic control process method for denitration in ammonia preparation from urea |
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| LU505199B1 true LU505199B1 (en) | 2024-03-28 |
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| LU505199A LU505199B1 (en) | 2023-09-28 | 2023-09-28 | Automatic control process method for denitration in ammonia preparation from urea |
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| LU (1) | LU505199B1 (en) |
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2023
- 2023-09-28 LU LU505199A patent/LU505199B1/en active IP Right Grant
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