Automatic adjusting system for denitration and ammonia injection of boiler

Abstract

The utility model discloses an automatic adjusting system for denitration and ammonia spraying of a boiler, which belongs to the technical field of automatic control and comprises a denitration outlet NOX collector, a desulfurization outlet NOX collector, a boiler load collector and a denitration inlet NOX collector. The output ends of the denitration outlet NOX collector and the desulfurization outlet NOX collector are connected with the main regulator, the output ends of the main regulator, the boiler load collector and the denitration inlet NOX collector are connected with the auxiliary regulator, and the auxiliary regulator is connected with the ammonia spraying regulating valve. The boiler load is brought into the influence factors of ammonia injection adjustment, the influence factors of ammonia injection automatic control can be analyzed more comprehensively by combining the content of NOx at a denitration outlet, the content of NOx at a desulfurization outlet and the content of NOx at a denitration inlet, and then the working state of an ammonia injection adjusting valve is controlled, so that the accuracy of ammonia injection automatic control is improved, optimization of ammonia injection automatic control is achieved, and the ammonia injection control efficiency is improved. And the NOX emission concentration of a denitration outlet is ensured to meet the environment-friendly requirement.

Description

Technical Field

[0001] The utility model relates to the technical field of automatic control, in particular to an automatic regulating system for boiler denitration and ammonia spraying. Background Art

[0002] In order to prevent the flue gas (including nitrogen oxides and sulfides) generated after the combustion of coal gas in the boiler from polluting the environment, the boiler flue gas should be denitrified and desulfurized. The more mature SCR denitrification technology currently adopts the selective catalytic reduction (SCR) method to achieve the purpose of removing nitrogen oxides in the flue gas. The block diagram of the boiler flue gas treatment system is as follows Figure 1 As shown, it includes a boiler, an SCR reactor, a desulfurization tower and a chimney connected in sequence. Ammonia (NH3) and nitrogen oxides generated by boiler combustion enter the SCR reactor for reaction to achieve the purpose of flue gas denitrification. The chemical reaction principle is as follows:

[0003] 4NO+4NH3+O2→4N2+6H2O

[0004] 6NO2+8NH3→7N2+12H2O

[0005] The remaining sulfide in the flue gas after denitrification is subjected to desulfurization reaction in the desulfurization tower. The chemical reaction principle is as follows:

[0006] Na2CO3 + SO2 → Na2SO3 + CO2↑ (1)

[0007] 2NaOH + SO2 → Na2SO3 + H2O (2)

[0008] Na2SO3+ SO2 + H2O → 2NaHSO3 (3)

[0009] Wherein: Formula (1) is the reaction of Na2SO3 solution absorbing SO2 during the startup phase; Formula (2) is the main reaction of the solution absorbing SO2 when the pH value of the regeneration solution is high (higher than 9); Formula (3) is the main reaction when the pH value of the solution is low (5-9).

[0010] After the boiler automatic denitrification system was officially put into operation, due to the imperfect design of the automatic adjustment of ammonia injection and the improper installation of on-site equipment, the automatic ammonia injection could not be put into operation normally, and it was completely dependent on manual control by the operating personnel, resulting in the inability to accurately control the NO at the denitrification outlet. X The emission concentration increases the workload of operators. The manual ammonia injection leads to an extremely unstable ammonia injection amount. Excessive ammonia injection leads to the production of harmful byproducts, which aggravates the blockage and corrosion of the heat exchange components of the boiler air preheater. If the ammonia injection amount is less than the required amount, the reaction is insufficient, resulting in NO XThe emission exceeds the standard. Since the amount of ammonia sprayed is mainly controlled by the ammonia flow regulating valve, in order to ensure that the denitrification outlet NO X It is particularly important to ensure that the emission concentration meets environmental protection requirements, control ammonia escape, and improve the performance of automatic control of ammonia injection in the denitrification system.

[0011] The initial ammonia injection automatic adjustment logic design of the boiler adopts the traditional PID adjustment. This design is not perfect and does not take into account the influence of multiple factors on ammonia injection adjustment. Therefore, the automatic control of ammonia injection for denitrification has not been put into normal operation. It has relied on manual adjustment by operators for a long time. When the load changes greatly, the NOx mass concentration at the denitrification outlet cannot be controlled in a timely and effective manner, which seriously affects the NO X To solve this problem and enable the effective use of ammonia injection automatic control, it is necessary to analyze the influencing factors of ammonia injection automatic control more comprehensively and optimize the existing ammonia injection automatic control. Utility Model Content

[0012] The utility model aims to overcome the problems of the prior art and provides a boiler denitration and ammonia spraying automatic regulating system.

[0013] The purpose of the utility model is to achieve the following technical solution: a boiler denitration ammonia injection automatic adjustment system, the system comprising:

[0014] Data acquisition unit, including denitrification outlet NO X Collector, desulfurization outlet NO X Collector, boiler load collector and denitrification inlet NO X Collector;

[0015] Denitrification outlet NO X Collector, desulfurization outlet NO X The output end of the collector is connected to the main regulator, the main regulator, the boiler load collector, the denitrification inlet NO X The output ends of the collectors are connected to the auxiliary regulators, and the auxiliary regulators are connected to the ammonia injection regulating valves.

[0016] In one example, the denitration outlet NO X Collector, desulfurization outlet NO X The output ends of the collectors are all connected to the first selector, and the output end of the first selector is connected to the main regulator.

[0017] In one example, the output end of the boiler load collector is connected to a first multiplier, and the denitration inlet NO X The output end of the collector is connected to the second multiplier, the output ends of the first multiplier and the second multiplier are connected to the third multiplier, the third multiplier is connected to the broken line function device, the output ends of the broken line function device and the main regulator are connected to the first adder, and the output end of the first adder is connected to the auxiliary regulator.

[0018] In one example, the data acquisition unit also includes a chimney outlet NO X Collector, chimney outlet NO X The output end of the collector is connected to the sub-regulator.

[0019] In one example, the denitration outlet NO X The output end of the collector and the output end of the main regulator are connected to the first relational operator via the first subtractor, and the input end of the first relational operator is also connected to the output end of the main regulator;

[0020] Chimney outlet NO X The output end of the collector and the output end of the main regulator are both connected to the second relational operator, the first relational operator and the second relational operator are connected to the second selector via the first OR gate and the first delay device, and the input end of the second selector is also connected to the main regulator;

[0021] The first subtractor, the first relational operator, the second relational operator, the OR gate, the first delay device, and the second selector form a deviation feedback unit, and the output of the second selector is the output of the deviation feedback unit.

[0022] In one example, the data acquisition unit further includes a coal powder production status collector and a coal machine coal shortage status collector, and the coal powder production status collector and the coal machine coal shortage status collector are both connected to the sub-regulator.

[0023] In one example, the coal powder production status collector and the coal machine coal shortage status collector are respectively connected to the selector y via a delay device x, where x and y are device numbers, x>1, y>2; the input end of each selector y is connected to the main regulator, and the output end of each selector y is connected to the second adder, and the output ends of the second adder and the deviation feedback unit are connected to the third adder, and the third adder and the first adder are connected to the sub-regulator via a fourth adder, and the delay device x, the selector y, and the third adder form a powder making feedforward unit.

[0024] It should be further explained that the technical features corresponding to the above examples can be combined or replaced with each other to form a new technical solution.

[0025] Compared with the prior art, the utility model has the following beneficial effects:

[0026] 1. In one example, the existing single-loop proportional-integral-derivative (PID) regulation is changed to cascade loop control, and the boiler load is included in the influencing factor of ammonia injection regulation, combined with the NO X Content, desulfurization outlet NO X Content, denitrification inlet NO XThe content can more comprehensively analyze the influencing factors of ammonia injection automatic control, and then control the working state of the ammonia injection regulating valve, so as to improve the accuracy of ammonia injection automatic control, realize the optimization of ammonia injection automatic control, and ensure the NO at the denitrification outlet X The emission concentration meets environmental protection requirements.

[0027] 2. In one example, the boiler load and denitrification inlet NO are calculated according to the boiler design documents. X The proportional calculation result is then converted into the required ammonia injection amount under the current load state by mathematical statistics based on the corresponding relationship between the boiler load and the ammonia injection amount provided by the process. The result is combined with the output of the control unit (main adjustment output) as the input of the automatic ammonia injection sub-adjustment, so as to perform automatic control of the ammonia injection regulation.

[0028] 3. In one example, the signal of the boiler unit starting and stopping the pulverizing system (coal powder production signal) is introduced as a feedforward signal to timely correct and compensate the chimney outlet NO X The trend of exceeding the standard can realize rapid response to various sudden changes in working conditions. X The occurrence of disturbance phenomenon can also make up for the lag of the reactor and flue gas analyzer and enhance the regulation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The same reference numerals are used in these drawings to represent the same or similar parts. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0030] Figure 1 A block diagram of a boiler flue gas treatment system provided as an example of the utility model;

[0031] Figure 2 A block diagram of an automatic regulation system for spraying nitric acid and ammonia provided as an example of the utility model;

[0032] Figure 3 A circuit schematic diagram of a selection control unit provided as an example of the utility model;

[0033] Figure 4 A load feedback unit circuit schematic diagram provided for an example of the utility model;

[0034] Figure 5 A schematic diagram of a deviation feedback unit circuit provided as an example of the utility model;

[0035] Figure 6 A schematic diagram of a powder making feedforward unit circuit provided as an example of the utility model;

[0036] Figure 7 A circuit schematic diagram of a unit for determining the condition of ammonia injection automatic forced switching to manual operation provided as an example of the utility model. DETAILED DESCRIPTION

[0037] The technical solution of the utility model is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0038] In the description of the present invention, it should be noted that the directions or positional relationships indicated by "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the directions or positional relationships described in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the use of ordinal numbers (for example, "first and second", "first to fourth", etc.) is to distinguish objects, and is not limited to this order, and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] In one example, a boiler denitrification ammonia injection automatic regulation system, such as Figure 2 As shown, the system includes a secondary regulator and a main regulator connected in series to form a cascade loop control, and the secondary regulator and the main regulator are preferably PID controllers. The system also includes a data acquisition unit, including a denitrification outlet NO X Collector, desulfurization outlet NO X Collector, boiler load collector and denitrification inlet NO X Collector. Among them, NO X The collector is used to collect NO XThe content (concentration) of NOx and SO2 is continuously analyzed and measured by existing sensors, such as flue gas analyzers, using electrochemical sensors (such as nitrogen oxide sensors and sulfur dioxide sensors). In this example, the denitrification outlet NO X Collector, boiler load collector and denitrification inlet NO X The collector can use a flue gas analyzer (flue gas NOx analyzer), and a flue gas analyzer is set at the denitrification inlet (the inlet pipeline of the SCR reactor), the denitrification outlet (the outlet pipeline of the SCR reactor), and the desulfurization outlet (the outlet pipeline of the desulfurization tower) to detect NO in various places of the boiler flue gas treatment system. X Content. The boiler load is the main steam flow value under the current working condition of the boiler. It is set behind the main steam electric door. The long-diameter nozzle used by the primary flow element passes through the flow F=K√ΔP, K is the flow coefficient of the primary element, ΔP is the pressure difference measured by the primary element, and the pressure difference is collected through the differential pressure transmitter. The differential pressure transmitter (the boiler load collector in this example) is connected to the sub-regulator to collect the real-time main steam flow. According to the relevant parameters provided by the boiler plant, the sub-regulator converts the estimated ammonia injection demand value according to the relationship between the current load and the flue gas. As an option, the main steam flow value can also be collected through a flow meter, that is, the boiler load collector is a flow meter, and the data output pin of the flow meter is connected to the sub-regulator.

[0042] Among them, the denitrification outlet NO X Collector, desulfurization outlet NO X The output end of the collector (data output pin of the sensor) is connected to the main regulator, the main regulator, the boiler load collector (data output pin), the denitrification inlet NO X The collectors (data output pins) are all connected to the sub-regulators, and the sub-regulators are connected to the ammonia injection regulating valves.

[0043] In this example, the existing single-loop proportional-integral-derivative (PID) regulation is changed to cascade loop control, and the current boiler load is included in the influencing factor of ammonia injection regulation. X Content, desulfurization outlet NO X Content, denitrification inlet NO X The content is transmitted to the sub-regulator based on the NO X The auxiliary regulator can more accurately calculate the ammonia content required for the current denitration reaction based on the content and boiler load, and then control the medium (ammonia) flow rate of the ammonia injection regulating valve, thereby improving the accuracy of the automatic control of ammonia injection, realizing the optimization of the automatic control of ammonia injection, and ensuring that the denitration outlet NO X The emission concentration meets environmental protection requirements. It should be noted that the data analysis process involved in the secondary regulator and the main regulator (such as the NO XThe content of ammonia required for the calculation of the content) belongs to the common knowledge of those skilled in the art and is not the technical content for which protection is sought in the present utility model.

[0044] In one example, if Figure 3 As shown, the denitrification outlet NO X Collector, desulfurization outlet NO X The output ends of the collectors are connected to the first selector SEL1, the output end of the first selector is connected to the main regulator, and the first selector and the main regulator form a selection control unit. X Is the analyzer in the purging state? Select the denitration outlet NO X Content or desulfurized flue gas NO X The content is used as the input value of the automatic main regulator of ammonia injection, such as the NO content of the flue gas at the denitrification outlet X The analyzer is in the purging state, select the denitrification outlet NO X The content is used as the input value of the automatic main regulator of ammonia injection, and the output limit of the main regulator is controlled between ±25% (adjustable on the PID control panel).

[0045] In one example, the system further includes a load feedback unit, including a first multiplier, a second multiplier, a third multiplier, and a broken line function. Figure 4 As shown, the output end of the boiler load collector is connected to the first multiplier MUL1, and the denitrification inlet NO X The output end of the collector is connected to the second multiplier MUL2, and the input ends of the first multiplier and the second multiplier are preferably connected to the main regulator, and then the weight values ​​of the two multipliers are set by the main regulator, and in this example, they are all 0.01. The output ends of the first multiplier and the second multiplier are both connected to the third multiplier MUL3, and the third multiplier is connected to the broken line function HSCHARC1. The output ends of the broken line function and the main regulator are both connected to the first adder, and the output end of the first adder is connected to the auxiliary regulator. In this example, according to the boiler design file (the file records the boiler load and the generated NO X Content (equivalent to denitrification inlet NO X The proportional relationship between boiler load and denitrification inlet NO X The proportional calculation result is then converted into the required ammonia injection amount under the current load state by a broken line function according to the corresponding relationship between the boiler load and the ammonia injection amount provided by the process (obtained based on the correction of historical data) through the method of mathematical statistics. The result is combined with the output of the control unit (the output of the main regulator) as the input of the automatic ammonia injection sub-regulation, so as to perform automatic control of the ammonia injection regulation.

[0046] In one example, the data collection unit also includes a chimney outlet NO XThe collector is a flue gas NOx analyzer arranged at the chimney outlet, and its data output pin is connected to the sub-regulator.

[0047] In one example, the system further includes a deviation feedback unit, which includes a first subtractor, a first relational operator, a second relational operator, an OR gate, a first delay device, and a second selector to form the deviation feedback unit. Figure 5 As shown, the output end of the main regulator is connected to the first subtractor SUB1, and then the denitration outlet NO is set through the main regulator. X Concentration setting value (based on historical experience or combined with the denitrification reaction situation to determine the current denitrification reaction produced NO X The concentration reference value is a fixed threshold value) and then input to the first subtractor; the denitrification outlet NO X The output end of the collector and the output end of the main regulator are connected to the first relational operator GE1 through the first subtractor SUB1. The first relational operator is a greater than or equal to relational operator. The input end of the first relational operator is also connected to the output end of the main regulator. The set value of the input first selector is set by the main regulator (a threshold value obtained based on historical experience or a threshold value calculated based on historical experience combined with the current denitration reaction situation), and then the denitration outlet NO is denitrated through the first subtractor. X The measured value and the set value are calculated for deviation, and then the deviation value is compared with the set value based on the first relational operator. X The output end of the collector and the output end of the main regulator are connected to the second relational operator GE2. In this example, the second relational operator is a greater than or equal to relational operator. The second relational operator is used to compare the desulfurization tower NO X The two relational operators are connected to the second selector SEL2 through the first OR gate OR1 and the first delay TOF1. The input of the second selector is also connected to the main regulator. The set value of the second selector is set by the main regulator. The output of the second selector is the output of the deviation feedback unit. The output of the deviation feedback unit is input to the sub-regulator. In this example, the denitrification outlet NO X The measured value is calculated with the set value. When the deviation value is ≥ the set value or the desulfurization tower NO X ≥ set value, the auxiliary regulator controls the ammonia injection regulating valve to increase the ammonia injection amount to compensate for the insufficient ammonia injection amount under the existing regulation conditions caused by the operating condition disturbance, resulting in the chimney flue gas NO X When the deviation value or chimney NOX returns to the normal control range, the sub-regulator will give feedback to the main regulator, and then the main regulator will control the first delayer to cancel the compensation after 35 seconds.

[0048] In one example, the data acquisition unit also includes a coal powder production state collector and a coal machine coal outage state collector, and the coal powder production state collector and the coal machine coal outage state collector are both connected to the sub-regulator. Among them, the coal powder production state includes two states: the powder making state and the stop powder making state. The boiler in this example is equipped with two sets of parallel powder making subsystems: the powder making (coal powder) subsystem on the A side and the powder making subsystem on the B side. The two powder making subsystems include one coal feeder, one coal mill, and one powder discharger. By monitoring the working state of the coal feeder, the coal mill, and the powder discharger, it is determined whether the current state is the powder making state or the stop powder making state. As an optional example, the coal powder production state collector and the coal machine coal outage state collector can be vibration sensors, such as setting the vibration sensor on the coal mill, and determining whether it is the powder making state or the stop powder making state by monitoring the vibration state of the coal mill. At this time, the data output pin of the vibration sensor is connected to the sub-regulator. As an optional example, the start and stop signals of the powder making subsystem are returned to the distributed control system DCS (the distributed control system DCS is connected to the sub-regulator) through the auxiliary contact signals of the circuit breakers of the three motors that control the coal feeder, coal mill, and powder discharger to judge the start and stop status of the powder making subsystem. Specifically, the coal feeder's coal-off signal is collected by a photoelectric switch and a fixed and flippable metal baffle set above the coal feeder belt, and the signal output end of the photoelectric switch is connected to the sub-regulator. When there is coal flow, the metal baffle follows the coal flow away from the photoelectric switch, and the photoelectric switch is disconnected. At this time, it is considered that the coal flow is normal and it is in the powder making state, and the sub-regulator outputs a powder making start signal; when there is no coal flow, the metal baffle is in a vertical state due to the influence of gravity, and the photoelectric switch is turned on at this time, and it is judged that it is in the coal-off state, that is, the powder making state is stopped, and the sub-regulator outputs a powder making stop signal.

[0049] In one example, the system further comprises a powder feedforward unit, specifically comprising a second delay, a third delay, a fourth delay, a fifth delay, a sixth delay, a seventh delay, a third selector, a fourth selector, a fifth selector, a sixth selector, a seventh selector, an eighth selector and a third adder, and the powder feedforward unit and the deviation feedback unit form a secondary loop feedforward. Figure 6As shown, the second delay device receives the start signal of the pulverizing on the A side, the third delay device receives the stop signal of the pulverizing on the A side, the fourth delay device receives the start signal of the pulverizing on the B side, the fifth delay device receives the stop signal of the pulverizing on the B side, the sixth delay device receives the coal supply and coal stop signal on the A side, and the seventh delay device receives the coal supply and coal stop signal on the B side. The six delay devices can be connected to the main regulator for delay setting. Furthermore, the six delay devices are respectively connected to the six selectors in a one-to-one correspondence, and the input ends of the six selectors can be connected to the main regulator to set the set value, so that the six selectors output the set value or the pulverizing start / stop signal or the coal supply and coal stop signal. This example introduces the start and stop pulverizing of the boiler device and the coal feeder coal stop signal. When the pulverizing is started, a certain amount of ammonia injection is increased, and the compensation is cancelled after a specific delay of time, such as 10 minutes, after the pulverizing is stopped. In this example, the signal (coal powder production signal) of the start and stop pulverizing system of the boiler device is introduced as a feedforward signal to timely correct and compensate the chimney outlet NO X The trend of exceeding the standard can realize rapid response to various sudden changes in working conditions. X The occurrence of disturbance phenomenon can also make up for the lag of the reactor and flue gas analyzer and enhance the regulation effect.

[0050] In one example, the data acquisition unit also includes an ammonia injection regulating valve position collector and an ammonia injection regulating valve switch state collector, and the output ends of the ammonia injection regulating valve position collector and the ammonia injection regulating valve switch state collector are connected to the sub-regulator. Preferably, an ammonia injection regulating valve with valve position feedback and switch state feedback can be used, such as a Goodyear 5100 control valve + Fisher DVC6200 positioner, to form an ammonia injection regulating valve. Of course, the valve position state and switch state of the current ammonia injection regulating valve can also be determined according to the instructions output by the sub-regulator. This example combines the state of the ammonia injection regulating valve and the NOx measurement value as the judgment conditions for automatic forced switching of ammonia injection to manual. Figure 7As shown, the second subtractor receives the ammonia injection regulating valve instruction and can be connected to the main regulator to realize signal reception; the second subtractor, the first greater than operator, and the first less than operator all receive the ammonia injection regulating valve feedback (switch state or flow value that can allow ammonia to pass), the first greater than operator and the first less than operator can be connected to the main regulator to set the reference value of the operation; the second subtractor is used to receive the main adjustment given value (main regulator given value) and is connected to the main regulator to realize signal reception; the third subtractor, the second greater than operator, and the second less than operator all receive the main adjustment measurement value (real-time NOx value output by the data acquisition unit), the second greater than operator and the second less than operator can be connected to the main regulator to set the reference value of the operation; further, the second subtractor is connected to the third greater than operator via the first absolute value operator, the third greater than operator, the first greater than operator, and the first less than operator The third subtractor is connected to the fourth greater than operator via the second absolute value operator, the fourth greater than operator, the second greater than operator, and the second less than operator are all connected to the third OR gate, the second OR gate and the third OR gate are all connected to the fourth OR gate, and the output end of the fourth OR gate is connected to the auxiliary regulator, so that the auxiliary regulator can obtain whether the current ammonia injection regulating valve, denitration reaction, etc. are in a normal state. For example, when the absolute value of the deviation between the regulating valve position and the instruction is ≥15%, the regulating valve feedback is ≥100 (valve failure), the regulating valve feedback is ≤-1 (valve failure), the main adjustment given value and the measured value deviation absolute value is ≥35, the main adjustment measured value is ≥100 (outside the normal value range), the main adjustment measured value is ≤-1 (outside the normal value range), etc., it indicates that a fault has occurred and it is in an abnormal state. At this time, the ammonia injection can be automatically forced to switch, and an audible and visual alarm can be performed at the same time to avoid the control parameter being out of control after automatic loss of control.

[0051] The above examples are combined to obtain a preferred example of the utility model. In this case, the system includes a data acquisition unit, a main regulator, a sub-regulator and an ammonia injection regulating valve. In this case, the data acquisition unit includes a denitrification outlet NO X Collector, desulfurization outlet NO X Collector, boiler load collector, denitrification inlet NO X Collector, chimney outlet NO X The connection relationship between the collector, the coal powder production status collector and the coal machine coal shortage status collector is as described in the above example, and will not be repeated here. In this example, the boiler load is included in the influencing factors of ammonia injection regulation, combined with the NO X The content of ammonia and the signal of the boiler unit's start-stop powder making system can be used to more comprehensively analyze the influencing factors of ammonia injection automatic control, and then control the working state of the ammonia injection regulating valve, so as to improve the accuracy of ammonia injection automatic control, realize the optimization of ammonia injection automatic control, and ensure that the denitrification outlet NO X The emission concentration meets environmental protection requirements.

[0052] The above specific implementation methods are detailed descriptions of the present utility model. It cannot be determined that the specific implementation methods of the present utility model are limited to these descriptions. For ordinary technicians in the technical field to which the present utility model belongs, they can make several simple deductions and substitutions without departing from the concept of the present utility model, which should be regarded as belonging to the protection scope of the present utility model.

Claims

1. A boiler denitration ammonia injection automatic adjustment system, characterized by: include: Data acquisition unit, including denitrification outlet NO X Collector, desulfurization outlet NO X Collector, boiler load collector and denitrification inlet NO X Collector; Denitrification outlet NO X Collector, desulfurization outlet NO X The output end of the collector is connected to the main regulator, the main regulator, the boiler load collector, the denitrification inlet NO X The output ends of the collectors are connected to the auxiliary regulators, and the auxiliary regulators are connected to the ammonia injection regulating valves.

2. The automatic regulation system for boiler denitration and ammonia injection according to claim 1 is characterized in that: The denitration outlet NO X Collector, desulfurization outlet NO X The output ends of the collectors are all connected to the first selector, and the output end of the first selector is connected to the main regulator.

3. The automatic regulation system for boiler denitration and ammonia injection according to claim 1 is characterized in that: The output end of the boiler load collector is connected to a first multiplier, and the denitration inlet NO X The output end of the collector is connected to the second multiplier, the output ends of the first multiplier and the second multiplier are connected to the third multiplier, the third multiplier is connected to the broken line function device, the output ends of the broken line function device and the main regulator are connected to the first adder, and the output end of the first adder is connected to the auxiliary regulator.

4. The automatic regulation system for boiler denitration and ammonia injection according to claim 3 is characterized in that: The data acquisition unit also includes a chimney outlet NO X Collector, chimney outlet NO X The output end of the collector is connected to the sub-regulator.

5. The automatic regulation system for boiler denitration and ammonia injection according to claim 4 is characterized in that: The denitration outlet NO X The output end of the collector and the output end of the main regulator are connected to the first relational operator via the first subtractor, and the input end of the first relational operator is also connected to the output end of the main regulator; Chimney outlet NO X The output end of the collector and the output end of the main regulator are both connected to the second relational operator, the first relational operator and the second relational operator are connected to the second selector via the first OR gate and the first delay device, and the input end of the second selector is also connected to the main regulator; The first subtractor, the first relational operator, the second relational operator, the first OR gate, the first delay device, and the second selector form a deviation feedback unit, and the output of the second selector is the output of the deviation feedback unit.

6. The automatic regulation system for boiler denitration and ammonia injection according to claim 5 is characterized in that: The data acquisition unit also includes a coal powder production status collector and a coal machine coal shortage status collector, and the coal powder production status collector and the coal machine coal shortage status collector are both connected to the auxiliary regulator.

7. The automatic regulation system for boiler denitration and ammonia injection according to claim 6 is characterized by: The coal powder production status collector and the coal machine coal shortage status collector are respectively connected to the selector y via a delay device x, where x and y are device numbers, x>1, y>2; the input end of each selector y is connected to the main regulator, and the output end of each selector y is connected to the second adder, and the output ends of the second adder and the deviation feedback unit are connected to the third adder, and the third adder and the first adder are connected to the sub-regulator via the fourth adder, and the delay device x, the selector y and the third adder form a powder making feedforward unit.

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