CN219308357U - Denitration refined ammonia spraying double-circulation control device - Google Patents
Denitration refined ammonia spraying double-circulation control device Download PDFInfo
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- CN219308357U CN219308357U CN202223374552.8U CN202223374552U CN219308357U CN 219308357 U CN219308357 U CN 219308357U CN 202223374552 U CN202223374552 U CN 202223374552U CN 219308357 U CN219308357 U CN 219308357U
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Abstract
The utility model discloses a denitration refined ammonia spraying double-circulation control device which can be connected with an SCR reactor of an SCR system of a unit, wherein the device comprises a total ammonia spraying regulating valve of the reactor, an ammonia/air mixer, an NOX grid measuring and sampling system, a matrix flowmeter, a flue partition plate, a partitioned ammonia/air mixer, an air-ammonia mixed gas flowmeter and a regulating electric executing mechanism. The device is provided with the matrix flowmeter through each subarea, is used for measuring the flow of the flue gas in the subarea of the inlet of the reactor, calculates the amount of the reducing agent required to be sprayed into each subarea by combining the measurement of the NOx concentration of the denitration inlet, further realizes the accurate control of the amount of the reducing agent in the subarea on the basis of the total amount control of the sprayed ammonia, and can further improve the NOx concentration of the SCR outlet and the uniformity of the ammonia escape distribution by controlling the valve regulating opening of each subarea on line in real time according to the amount of the reducing agent.
Description
Technical Field
The utility model belongs to the technical field of environmental protection equipment, and particularly relates to a denitration refined ammonia injection double-circulation control device.
Background
At present, in the conventional denitration process, when load changes, the concentration of NOx at a denitration inlet is changed severely, so that ultra-low emission is ensured, the condition of excessive ammonia injection is serious, and air preheater blockage and downstream equipment faults are easily caused, wherein the problems comprise a series of problems of unit safety reduction, resistance increase of a wind flue system, deterioration of heat exchange effect, increase of overhaul and maintenance quantity, bag pasting of a bag-type dust collector, ammonia escape exceeding, ammonia nitrogen exceeding of desulfurization wastewater, material consumption increase, electricity consumption increase, exhaust gas temperature rise and the like, and a large amount of ammonia escapes simultaneously, so that secondary pollution to the atmospheric environment is also generated.
In addition, the traditional CMES (continuous flue gas monitoring system) measuring instrument usually adopts a single-point sampling measurement mode, and usually the measured value can not reflect accurate actual flue gas flow and NOx concentration at the inlet and outlet of the reactor, and cannot feed back the actual distribution condition of the flue gas flow and the NOx concentration in the flue.
In the third and common refined ammonia spraying technology, the ammonia spraying transformation of the denitration inlet flue in the partition area and the transformation of the denitration outlet grid sampling measuring instrument are emphasized, and only the ammonia spraying main valve has a certain control effect, so that the ammonia spraying partition valve always needs to be manually calibrated, and the amount of reducing agent sprayed into each partition area cannot be effectively and accurately controlled in real time and on line.
Meanwhile, the ammonia injection amount of the SCR is regulated only by the total amount, the traditional zoned manual valve generally requires uniform and stable flue gas distribution of a denitration inlet, and the opening of each manual regulating valve is regulated according to the NOx concentration distribution of the SCR inlet, so that the amount of reducing agent injected into each zone is controlled, and the online real-time regulation function cannot be realized. Along with the technical requirements of thermal power generating unit flexibility transformation and deep peak shaving, the mode of manual adjustment caused by large load fluctuation can not meet the requirements of stable standard emission of the SCR denitration device.
There is thus a need for one or more related devices.
By searching, no patent publication related to the present patent application has been found.
Disclosure of Invention
The utility model aims to overcome the defects in the prior art and provides a denitration refined ammonia injection double-circulation control device.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
the device comprises a reactor ammonia injection total regulating valve, an ammonia/air mixer, an NOX grid measurement sampling system, a matrix type flowmeter, a flue partition baffle, a partitioned ammonia/air mixer, an air-ammonia mixed gas flowmeter and a regulating type electric actuating mechanism, wherein the matrix type flowmeter is connected with an inlet flue and comprises a plurality of flowmeters, the inlet of the inlet flue is sequentially connected with the NOX grid measurement sampling system and the flowmeters, and the outlet of the outlet flue is connected with the NOX grid measurement sampling system;
the inlet flue and the outlet flue are internally and tightly connected with each other, a plurality of flue partition plates are arranged in parallel with the direction of air flow, the inlet flue is divided into a plurality of independently arranged inlet partition flues by the plurality of flue partition plates, the outlet flue is divided into a plurality of independently arranged outlet partition flues by the plurality of flue partition plates, and the matrix flowmeter is also connected with the inside of each inlet partition flue;
the NOx grid measurement sampling system is also connected with the inlet of each inlet partition flue and the outlet of each outlet partition flue;
the input end of the ammonia/air mixer comprises an ammonia input end and an air input end, the air input end of the ammonia/air mixer is connected with an air input device, the air input device can input air to the ammonia/air mixer, the ammonia input device is tightly connected with the ammonia input end of the ammonia/air mixer through a switch valve and a reactor ammonia spraying total regulating valve in sequence, and the ammonia input device can input ammonia to the ammonia/air mixer;
the output end of the ammonia/air mixer is closely connected with the partition flue of each inlet flue through the partition ammonia/air mixer, the air-ammonia mixed gas flowmeter and the adjusting electric actuating mechanism in sequence.
Further, the matrix flowmeter can perform online rapid fracture surface scanning measurement on the flue gas flow at the inlet of the inlet flue of the SCR reactor, and can simultaneously measure the cross-section flue gas flow at the inlet of the inlet flue and the flue gas flow in each inlet partition flue;
the NOX grid measurement sampling system can measure NOX concentration at the inlet of the inlet flue, the outlet of the outlet flue, the inlet of each inlet partition flue and the outlet of each outlet partition flue;
the ammonia/air mixer of the partition can uniformly mix the smoke components;
the air-ammonia mixed gas flowmeter can measure the flow of air-ammonia mixed gas, and the adjusting type electric actuating mechanism can adjust the flow of each inlet partition flue denitration reducing agent.
Further, the adjusting type electric actuating mechanism is an adjusting valve.
Further, the adjusting type electric actuating mechanism is an electric adjusting valve.
Further, the NOX grid measurement sampling system can switch between two measurement modes, namely, a patrol zone sampling measurement and a hybrid integrated sampling measurement, for NOX concentration of each zone.
Further, the number of the SCR reactors of the unit SCR system is 2.
The method for carrying out denitration and fine ammonia injection by using the denitration and fine ammonia injection double-circulation control device realizes an ammonia injection total amount control and partition fine adjustment double-circulation real-time on-line fine control strategy based on a partition flow measurement and inlet and outlet NOX grid sampling measurement double-fine measurement mode, and specifically comprises the following steps:
(1) Each reactor flue of each unit SCR system is divided into N areas, firstly, each area is additionally provided with an ammonia/air mixer of each area, and smoke components are basically and uniformly mixed through the ammonia/air mixer of each area;
(2) Each reactor inlet of the SCR system is provided with a set of matrix flowmeter, the matrix flowmeter carries out online rapid fracture surface scanning measurement on the flue gas flow of the SCR inlet, and the matrix flowmeter can also simultaneously measure the section flue gas flow of each reactor inlet flue and the flue gas flow of each region of each inlet partition flue;
(3) An inlet flue and an outlet flue of each reactor of the SCR system are respectively provided with a set of NOX grid measuring and sampling system which is used for measuring NOX concentration at the inlet of the inlet flue, the outlet of the outlet flue, the inlet of each inlet partition flue and the outlet of each outlet partition flue;
(4) Each inlet partition flue is provided with 1 set of air-ammonia mixed gas flowmeter for measuring air-ammonia mixed gas flow, and 1 set of adjusting electric actuating mechanism for adjusting denitration reducing agent flow of each inlet partition flue;
(5) The matrix flowmeter is used for simultaneously measuring the flue gas flow of the inlet flue section of each reactor, the NOx concentration of the inlet and outlet of each reactor is measured by combining a denitration inlet and outlet NOx grid sampling measurement system, and the reducing agent required to be sprayed into each reactor is calculated according to the formula NOx flow = flue gas flow x (outlet NOx concentration-inlet NOx concentration), so that the control of the total ammonia spraying amount corresponding to each reactor is realized, the adjustment opening of the total ammonia spraying adjusting valve of each reactor is controlled on line in real time according to the formula NOx flow = flue gas flow x (outlet NOx concentration-inlet NOx concentration), and the excessive ammonia spraying of an SCR system can be avoided;
(6) The method comprises the steps of respectively measuring the flue gas flow in each inlet partition flue of a reactor by using a matrix flowmeter, measuring the NOX concentration of each inlet partition flue by combining a denitration inlet NOX grid sampling measurement system, calculating the reducing agent amount respectively required to be sprayed into each inlet partition flue according to the formula NOX flow = flue gas flow x (outlet NOX concentration-inlet NOX concentration), and further realizing the accurate control of the reducing agent amount of each partition by using an adjusting type electric actuator corresponding to each partition on the basis of the total ammonia spraying amount control, so that the adjusting opening degree of each partition valve, namely the adjusting type electric actuator, is controlled in real time on line, and the concentration of NOX of an SCR outlet and the uniformity of ammonia escape distribution can be further improved.
The method for carrying out denitration and fine ammonia injection by using the denitration and fine ammonia injection double-circulation control device comprises the following steps when the SCR system of each unit is set to be 2 reactors:
(1) Each unit SCR system is divided into 2 reactors, each reactor flue is divided into N areas, 2N subareas are added, firstly, each subarea is additionally provided with a subarea mixer, and smoke components are basically and uniformly mixed through the subarea mixer;
(2) A set of matrix flow meters are respectively arranged at 2 reactor inlets of the SCR system, the measuring system carries out online rapid fracture scanning measurement on the flue gas flow of the SCR inlet, and the matrix flow meters can simultaneously measure the flue gas flow of the section of a flue of the 2 reactor inlets and the flue gas flow of each region of 2N subareas;
(3) A set of grid measurement sampling system of an NOX grid sampling measurement system is respectively arranged at the inlet and outlet of 2 reactors of the SCR system, and is used for switching two measurement modes of cruising regional sampling measurement and mixing comprehensive sampling measurement of NOX concentration of each regional;
(4) Each subarea is provided with 1 set of air-ammonia mixed gas flowmeter for measuring air-ammonia mixed gas flow, and 1 set of adjusting type electric actuating mechanism for adjusting the flow of the denitration reducing agent in each subarea;
(5) The matrix flowmeter is used for simultaneously measuring the flue gas flow of the inlet flue section of the 2 reactors, the NOx concentration of the inlet and outlet partitions of the 2 reactors is measured through a mixed comprehensive sampling measurement mode by combining a denitration inlet and outlet NOx grid sampling measurement system, and the reducing agent quantity required to be sprayed into each of the 2 reactors is calculated according to the formula NOx flow = flue gas flow x (outlet NOx concentration-inlet NOx concentration), so that the control of the total ammonia spraying quantity corresponding to each of the 2 reactors is realized, the opening degree of the ammonia spraying valves of the 2 reactors is controlled on line in real time based on the control, and the excessive ammonia spraying of an SCR system can be avoided;
(6) The method is characterized in that the flue gas flow in 2N subareas of the reactor inlet is respectively measured by using a matrix flowmeter, the NOx concentration of the 2N inlet subareas is measured by combining a denitration inlet NOx grid sampling measurement system through a circulating subarea sampling measurement mode, the reducing agent amount required to be sprayed into the 2N subareas is calculated according to the formula NOx flow = flue gas flow x (outlet NOx concentration-inlet NOx concentration), on the basis of total ammonia spraying amount control, the accurate control of the reducing agent amount of each subarea is further realized through an adjusting type electric actuator corresponding to each subarea, and on the basis, the adjusting opening degree of each subarea valve, namely the adjusting type electric actuator, is controlled in real time on line, so that the NOx concentration of an SCR outlet and the uniformity of ammonia escape distribution can be further improved.
The denitration refined ammonia injection double-circulation control device is applied to denitration.
The utility model has the advantages and effects that:
1. the device is provided with the matrix flowmeter through each subarea, is used for measuring the flow of the flue gas in the subarea of the inlet of the reactor, calculates the amount of the reducing agent required to be sprayed into each subarea by combining the measurement of the NOx concentration of the denitration inlet, further realizes the accurate control of the amount of the reducing agent in the subarea on the basis of the total amount control of the sprayed ammonia, and can further improve the NOx concentration of the SCR outlet and the uniformity of the ammonia escape distribution by controlling the valve regulating opening of each subarea on line in real time according to the amount of the reducing agent.
2. The device disclosed by the utility model is optimized and improved aiming at some problems commonly existing in the denitration technology, so that the concentration of NOx at an SCR outlet and the uniformity of ammonia slip distribution are improved, the local ammonia slip concentration is reduced, the ABS blockage of an air preheater is lightened, and the fine control level of an SCR denitration system is improved.
3. Denitration outlet (SCR outlet) and discharge outlet (clean flue gas) nitrogen oxidation after treatment by the deviceThe deviation of the measured data of the object is controlled to be 5mg/m 3 In addition, the situation of 'data hanging upside down' does not occur, and the ash blocking phenomenon does not occur.
4. The device can save a large amount of liquid ammonia, reduce ammonia escape, prolong the service life of the catalyst, improve the surrounding environment, enhance the heat efficiency of the system, prevent the air preheater from being blocked and reduce the power consumption of the induced draft fan. The control of the NOx value of the clean flue gas is more stable, and the occurrence of environmental protection check can be effectively reduced.
5. By using the device of the utility model, the NOx at the inlet of the denitration device is not higher than 500mg/Nm 3 Under the condition of ensuring that the denitration efficiency of the denitration system is not lower than 90%, and NOx at the SCR outlet<50mg/Nm 3 (6% oxygen, dry state), ammonia slip<2.5ppm。
5. With the device of the utility model, the NOx control error (the difference between the actual value and the set value) of the clean flue gas is not more than 6mg/Nm under the stable load of the unit 3 。
6. By using the device, under the variable load working condition of the unit, the NOx control error (the difference between the actual value and the set value) of the clean flue gas is not more than 15mg/Nm3.
7. By using the device, the NOx control error (the difference between the actual value and the set value) of the flue gas is not more than 20mg/Nm3 in the process of starting and stopping the grinding.
8. The conventional flue gas flow measurement point only has one CEMS self-contained temperature-pressure flow integrated instrument to measure flow, because of single-point measurement, the measurement value cannot reflect accurate actual flue gas flow, in addition, the measurement of NOX in the conventional CMES is single-point measurement, the distribution condition of NOX concentration on the section of the flue at the inlet and outlet of the SCR reactor cannot be accurately reflected, and according to the formula NOX flow = flue gas flow x (outlet NOX concentration-inlet NOX concentration), when the flue gas flow and NOX concentration cannot be accurately measured, the accurate control of the SCR system cannot be necessarily realized. Based on the reasons, the device provided by the utility model firstly partitions the flue of the SCR reactor, is additionally provided with the partitioned ammonia/air mixer, ensures that the flow fields of all partitions and the NOx concentration fields are uniformly mixed, secondly, is respectively provided with the matrix flowmeter at the inlet flue of the SCR system reactor (such as 2 reactors), is respectively provided with the NOx grid sampling measurement system at the outlet flue of the SCR system reactor, realizes the accurate measurement of the flue gas flow and the NOx concentration of the outlet and inlet of each partition, firstly controls the total ammonia injection regulating valve of the reactor through calculation, and then is respectively provided with the air-ammonia mixed gas flowmeter and the regulating type electric actuator at each partition for the fine control and regulation of the flow of the denitration reducing agent of each partition, thereby avoiding the excessive ammonia injection of the SCR system, improving the NOx concentration and the ammonia escape distribution uniformity of the SCR system and improving the fine control level of the SCR denitration system.
Drawings
FIG. 1 is a schematic diagram of a structural connection of the apparatus of the present utility model;
FIG. 2 is a schematic diagram of the structural installation of the total reactor ammonia injection control valve, ammonia/air mixer, inlet stack and the regulated electric actuator in the apparatus of the present utility model.
Detailed Description
The utility model will now be further described in connection with specific examples which are intended to be illustrative only and not limiting in any way.
The raw materials used in the utility model are conventional commercial products unless otherwise specified, the methods used in the utility model are conventional methods in the art unless otherwise specified, and the mass of each substance used in the utility model is conventional. Structures, connection relationships, etc., not described in detail in the present utility model, may be understood as conventional means in the art.
The device comprises a reactor ammonia injection total regulating valve 2, an ammonia/air mixer 3, an NOX grid measurement sampling system 10, a matrix flowmeter, a flue partition baffle (not shown), a partitioned ammonia/air mixer (not shown), an air-ammonia mixed gas flowmeter 4 and a regulating type electric actuator 5, wherein the matrix flowmeter is connected with an inlet flue, the matrix flowmeter comprises a plurality of flowmeters, the SCR reactor comprises an inlet flue 7 and an outlet flue 12, the NOX grid measurement sampling system and a plurality of flowmeters 9 are sequentially connected at the inlet of the inlet flue, and the NOX grid measurement sampling system is connected at the outlet of the outlet flue;
the inlet flue and the outlet flue are internally and tightly connected with each other, a plurality of flue partition plates are arranged in parallel with the direction of air flow, the inlet flue is divided into a plurality of independently arranged inlet partition flues 6 by the plurality of flue partition plates, the outlet flue is divided into a plurality of independently arranged outlet partition flues (not shown in the figure) by the plurality of flue partition plates, and the matrix flowmeter is also connected with the inside of each inlet partition flue;
the NOx grid measurement sampling system is also connected with the inlet of each inlet partition flue and the outlet of each outlet partition flue;
the input end of the ammonia/air mixer comprises an ammonia input end 31 and an air input end 32, the air input end of the ammonia/air mixer is connected with an air input device (not shown in the figure), the air input device can input air to the ammonia/air mixer, the ammonia input device (not shown in the figure) is tightly connected with the ammonia input end of the ammonia/air mixer through a switch valve 1 and a reactor ammonia spraying total regulating valve in sequence, and the ammonia input device can input ammonia to the ammonia/air mixer;
the output end of the ammonia/air mixer is closely connected with the partition flue of each inlet flue through the partition ammonia/air mixer, the air-ammonia mixed gas flowmeter and the adjusting electric actuating mechanism in sequence.
The conventional flue gas flow measurement point only has one CEMS self-contained temperature-pressure flow integrated instrument to measure flow, because of single-point measurement, the measurement value cannot reflect accurate actual flue gas flow, in addition, the measurement of NOX in the conventional CMES is single-point measurement, the distribution condition of NOX concentration on the section of the flue at the inlet and outlet of the SCR reactor cannot be accurately reflected, and according to the formula NOX flow = flue gas flow x (outlet NOX concentration-inlet NOX concentration), when the flue gas flow and NOX concentration cannot be accurately measured, the accurate control of the SCR system cannot be necessarily realized. Based on the reasons, the device provided by the utility model firstly partitions the flue of the SCR reactor, is additionally provided with the partitioned ammonia/air mixer, ensures that the flow fields of all partitions and the NOx concentration fields are uniformly mixed, secondly, is respectively provided with the matrix flowmeter at the inlet flue of the SCR system reactor (such as 2 reactors), is respectively provided with the NOx grid sampling measurement system at the outlet flue of the SCR system reactor, realizes the accurate measurement of the flue gas flow and the NOx concentration of the outlet and inlet of each partition, firstly controls the total ammonia injection regulating valve of the reactor through calculation, and then is respectively provided with the air-ammonia mixed gas flowmeter and the regulating type electric actuator at each partition for the fine control and regulation of the flow of the denitration reducing agent of each partition, thereby avoiding the excessive ammonia injection of the SCR system, improving the NOx concentration and the ammonia escape distribution uniformity of the SCR system and improving the fine control level of the SCR denitration system.
In this embodiment, the matrix flowmeter can perform online rapid fracture surface scanning measurement on the flue gas flow at the inlet of the inlet flue of the SCR reactor, and the matrix flowmeter can measure the cross-section flue gas flow at the inlet of the inlet flue and the flue gas flow in each inlet partition flue at the same time;
the NOX grid measurement sampling system can measure NOX concentration at the inlet of the inlet flue, the outlet of the outlet flue, the inlet of each inlet partition flue and the outlet of each outlet partition flue;
the ammonia/air mixer of the partition can uniformly mix the smoke components;
the air-ammonia mixed gas flowmeter can measure the flow of air-ammonia mixed gas, and the adjusting type electric actuating mechanism can adjust the flow of each inlet partition flue denitration reducing agent.
In this embodiment, the adjusting electric actuator is an adjusting valve, preferably an electric adjusting valve.
In this embodiment, the NOX grid measurement sampling system can switch between two measurement modes, i.e., a cyclic zone sampling measurement and a hybrid integrated sampling measurement, for NOX concentration in each zone. The NOX grid measurement sampling system in the present device is a common device in the prior art, and for example, it may be disclosed in patent publication nos. CN214552557U and CN 214150046U.
In this embodiment, the SCR reactors of the unit SCR system are set to 2.
The method for carrying out denitration and fine ammonia injection by using the denitration and fine ammonia injection double-circulation control device realizes an ammonia injection total amount control and partition fine adjustment double-circulation real-time on-line fine control strategy based on a partition flow measurement and inlet and outlet NOX grid sampling measurement double-fine measurement mode, and specifically comprises the following steps:
(1) Each reactor flue of each unit SCR system is divided into N areas, firstly, each area is additionally provided with an ammonia/air mixer of each area, and smoke components are basically and uniformly mixed through the ammonia/air mixer of each area;
(2) Each reactor inlet of the SCR system is provided with a set of matrix flowmeter, the matrix flowmeter carries out online rapid fracture surface scanning measurement on the flue gas flow of the SCR inlet, and the matrix flowmeter can also simultaneously measure the section flue gas flow of each reactor inlet flue and the flue gas flow of each region of each inlet partition flue;
(3) An inlet flue and an outlet flue of each reactor of the SCR system are respectively provided with a set of NOX grid measuring and sampling system which is used for measuring NOX concentration at the inlet of the inlet flue, the outlet of the outlet flue, the inlet of each inlet partition flue and the outlet of each outlet partition flue;
(4) Each inlet partition flue is provided with 1 set of air-ammonia mixed gas flowmeter for measuring air-ammonia mixed gas flow, and 1 set of adjusting electric actuating mechanism for adjusting denitration reducing agent flow of each inlet partition flue;
(5) The matrix flowmeter is used for simultaneously measuring the flue gas flow of the inlet flue section of each reactor, the NOx concentration of the inlet and outlet of each reactor is measured by combining a denitration inlet and outlet NOx grid sampling measurement system (for example, a mixed comprehensive sampling measurement mode is adopted), the amount of reducing agent required to be sprayed into each reactor is calculated according to the formula NOx flow = flue gas flow x (outlet NOx concentration-inlet NOx concentration), and therefore the control of the total amount of ammonia spraying corresponding to each reactor is realized, the adjustment opening of an ammonia spraying total regulating valve of each reactor is controlled on line in real time according to the control, and excessive ammonia spraying of an SCR system can be avoided;
(6) The method comprises the steps of respectively measuring the flue gas flow in each inlet partition flue of a reactor by using a matrix flowmeter, measuring the NOX concentration of each inlet partition flue by combining a denitration inlet NOX grid sampling measurement system (for example, through a patrol partition sampling measurement mode), calculating the amount of reducing agent required to be sprayed into each inlet partition flue according to the formula NOX flow = flue gas flow x (outlet NOX concentration-inlet NOX concentration), and further realizing accurate control of the reducing agent amount of each partition by using an adjusting type electric actuator corresponding to each partition on the basis of total ammonia spraying amount control, so that the adjusting opening degree of each partition valve (namely the adjusting type electric actuator) is controlled on line in real time, and the concentration of NOX of an SCR outlet and the uniformity of ammonia escape distribution can be further improved.
Preferably, when each unit SCR system is set to 2 reactors, the method comprises the steps of:
(1) Each unit SCR system is divided into 2 reactors, each reactor flue is divided into N areas, 2N subareas are added, firstly, each subarea is additionally provided with a subarea mixer, and smoke components are basically and uniformly mixed through the subarea mixer;
(2) A set of matrix flow meters are respectively arranged at 2 reactor inlets of the SCR system, the measuring system carries out online rapid fracture scanning measurement on the flue gas flow of the SCR inlet, and the matrix flow meters can simultaneously measure the flue gas flow of the section of a flue of the 2 reactor inlets and the flue gas flow of each region of 2N subareas;
(3) A set of grid measurement sampling system of an NOX grid sampling measurement system is respectively arranged at the inlet and outlet of 2 reactors of the SCR system, and is used for switching two measurement modes of cruising regional sampling measurement and mixing comprehensive sampling measurement of NOX concentration of each regional;
(4) Each subarea is provided with 1 set of air-ammonia mixed gas flowmeter for measuring air-ammonia mixed gas flow, and 1 set of adjusting type electric actuating mechanism for adjusting the flow of the denitration reducing agent in each subarea;
(5) The method has the advantages that the matrix flowmeter is used for simultaneously measuring the flue gas flow of the inlet flue section of 2 reactors, the NOx concentration of the inlet and outlet partitions of the 2 reactors is measured through a mixed comprehensive sampling measurement mode by combining a denitration inlet and outlet NOx grid sampling measurement system, and the reducing agent quantity required to be sprayed into each of the 2 reactors is calculated according to the formula NOx flow = flue gas flow x (outlet NOx concentration-inlet NOx concentration), so that the control of the total ammonia spraying quantity corresponding to each of the 2 reactors is realized, the ammonia spraying valve adjusting opening of the 2 reactors is controlled on line in real time based on the control, and excessive ammonia spraying of an SCR system can be avoided;
(6) The method comprises the steps of measuring the flow of the flue gas in 2N subareas of a reactor inlet by using a matrix flowmeter respectively, measuring the NOX concentration of the 2N inlet subareas by combining a denitration inlet NOX grid sampling measurement system through a circulating subarea sampling measurement mode, calculating the reducing agent quantity required to be sprayed into the 2N subareas respectively according to the formula NOX flow = flue gas flow x (outlet NOX concentration-inlet NOX concentration), and further realizing accurate control of the reducing agent quantity of each subarea by using an adjusting type electric actuator corresponding to each subarea on the basis of total ammonia spraying amount control, wherein the adjusting opening degree of each subarea valve (namely the adjusting type electric actuator) is controlled in real time on line, and the concentration of the NOX of an SCR outlet and the uniformity of ammonia escape distribution can be further improved.
The correlation detection of the utility model is as follows:
in the prior art, under the steady load of the unit, the NOx control error (the difference between the actual value and the set value) of the clean flue gas is not more than 10mg/Nm 3 . After the device is used, under the stable load of the unit, the NOx control error (the difference between the actual value and the set value) of the purified flue gas is not more than 6mg/Nm 3 . In addition, NOx at the inlet of the denitration device is not higher than 500mg/Nm 3 Under the condition of ensuring that the denitration efficiency of the denitration system is not lower than 90%, and NOx at the SCR outlet<50mg/Nm 3 (6% oxygen, dry state), ammonia slip<2.5ppm。
Under the variable load working condition of the unit, the NOx control error (the difference between the actual value and the set value) of the clean flue gas is not more than 15mg/Nm3. In the process of starting and stopping grinding, the NOx control error (the difference between the actual value and the set value) of the flue gas is not more than 20mg/Nm3.
By using the device of the utility model, the NOx at the inlet of the denitration device is not higher than 500mg/Nm 3 Under the condition of ensuring that the denitration efficiency of the denitration system is not lower than 90%, and NOx at the SCR outlet<50mg/Nm 3 (6% oxygen, dry state), ammonia slip<2.5ppm。
The working principle of the denitration refined ammonia injection double-circulation control device can be as follows:
the conventional flue gas flow measurement point only has one CEMS self-contained temperature-pressure flow integrated instrument to measure flow, because of single-point measurement, the measurement value cannot reflect accurate actual flue gas flow, in addition, the measurement of NOX in the conventional CMES is single-point measurement, the distribution condition of NOX concentration on the section of the flue at the inlet and outlet of the SCR reactor cannot be accurately reflected, and according to the formula NOX flow = flue gas flow x (outlet NOX concentration-inlet NOX concentration), when the flue gas flow and NOX concentration cannot be accurately measured, the accurate control of the SCR system cannot be necessarily realized. According to the method, firstly, the SCR reactor is partitioned, a partition mixer is additionally arranged, uniform mixing of each partition flow field and the NOx concentration field is guaranteed, secondly, a set of matrix flow meters are respectively arranged at inlets of 2 reactors of the SCR system, a set of NOx grid sampling measurement system is respectively arranged at inlets and outlets of 2 reactors of the SCR system, accurate measurement of flue gas flow and NOx concentration at inlets and outlets of each partition is achieved, firstly, the total ammonia spraying valve of 2 reactors of the SCR system is controlled through calculation, and then, 1 set of air-ammonia mixed gas flow meters and 1 set of adjusting type electric actuating mechanism are respectively arranged at each partition for fine control and adjustment of the flow of each partition denitration reducing agent, so that excessive ammonia spraying of the SCR system is avoided, the NOx concentration at outlets of the SCR system and the ammonia escape distribution uniformity are improved, and the fine control level of the SCR denitration system is improved.
Although embodiments of the present utility model have been disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the utility model and the appended claims, and therefore the scope of the utility model is not limited to the disclosure of the embodiments.
Claims (6)
1. The utility model provides a denitration fine ammonia spraying double circulation controlling means which characterized in that: the device can be connected with an SCR reactor of a unit SCR system, the device comprises a reactor ammonia spraying total regulating valve, an ammonia/air mixer, an NOX grid measurement sampling system, a matrix flowmeter, a flue partition plate, a partitioned ammonia/air mixer, an air-ammonia mixed gas flowmeter and a regulating type electric actuating mechanism, the matrix flowmeter is connected with an inlet flue and comprises a plurality of flowmeters, the SCR reactor comprises an inlet flue and an outlet flue, the NOX grid measurement sampling system and the plurality of flowmeters are sequentially connected at the inlet of the inlet flue, and the NOX grid measurement sampling system is connected at the outlet of the outlet flue;
the inlet flue and the outlet flue are internally and tightly connected with each other, a plurality of flue partition plates are arranged in parallel with the direction of air flow, the inlet flue is divided into a plurality of independently arranged inlet partition flues by the plurality of flue partition plates, the outlet flue is divided into a plurality of independently arranged outlet partition flues by the plurality of flue partition plates, and the matrix flowmeter is also connected with the inside of each inlet partition flue;
the NOx grid measurement sampling system is also connected with the inlet of each inlet partition flue and the outlet of each outlet partition flue;
the input end of the ammonia/air mixer comprises an ammonia input end and an air input end, the air input end of the ammonia/air mixer is connected with an air input device, the air input device can input air to the ammonia/air mixer, the ammonia input device is tightly connected with the ammonia input end of the ammonia/air mixer through a switch valve and a reactor ammonia spraying total regulating valve in sequence, and the ammonia input device can input ammonia to the ammonia/air mixer;
the output end of the ammonia/air mixer is closely connected with the partition flue of each inlet flue through the partition ammonia/air mixer, the air-ammonia mixed gas flowmeter and the adjusting electric actuating mechanism in sequence.
2. The denitration and refinement ammonia injection double-circulation control device according to claim 1, wherein: the matrix flowmeter can perform online rapid fracture scanning measurement on the flue gas flow at the inlet of the inlet flue of the SCR reactor, and can simultaneously measure the cross-section flue gas flow at the inlet of the inlet flue and the flue gas flow in each inlet partition flue;
the NOX grid measurement sampling system can measure NOX concentration at the inlet of the inlet flue, the outlet of the outlet flue, the inlet of each inlet partition flue and the outlet of each outlet partition flue;
the ammonia/air mixer of the partition can uniformly mix the smoke components;
the air-ammonia mixed gas flowmeter can measure the flow of air-ammonia mixed gas, and the adjusting type electric actuating mechanism can adjust the flow of each inlet partition flue denitration reducing agent.
3. The denitration and refinement ammonia injection double-circulation control device according to claim 1, wherein: the adjusting type electric actuating mechanism is an adjusting valve.
4. The denitration and refinement ammonia injection double-circulation control device according to claim 3, wherein: the adjusting type electric actuating mechanism is an electric adjusting valve.
5. The denitration and refinement ammonia injection double-circulation control device according to claim 1, wherein: the NOx grid measurement sampling system can switch between two measurement modes, namely, the cruising zone sampling measurement and the mixing comprehensive sampling measurement, for the NOx concentration of each zone.
6. The denitration and fine ammonia injection double-circulation control device according to any one of claims 1 to 5, characterized in that: the number of the SCR reactors of the unit SCR system is 2.
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| CN202223374552.8U CN219308357U (en) | 2022-12-15 | 2022-12-15 | Denitration refined ammonia spraying double-circulation control device |
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| CN202223374552.8U CN219308357U (en) | 2022-12-15 | 2022-12-15 | Denitration refined ammonia spraying double-circulation control device |
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