CN111135683B - SNCR denitration automatic control method and system - Google Patents
SNCR denitration automatic control method and system Download PDFInfo
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- CN111135683B CN111135683B CN202010122628.4A CN202010122628A CN111135683B CN 111135683 B CN111135683 B CN 111135683B CN 202010122628 A CN202010122628 A CN 202010122628A CN 111135683 B CN111135683 B CN 111135683B
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- B01D53/34—Chemical or biological purification of waste gases
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- B01D53/34—Chemical or biological purification of waste gases
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Abstract
The invention discloses an SNCR (selective non-catalytic reduction) denitration automatic control method and system, wherein the method comprises the steps of 1-5, the system comprises a control module, an ammonia pump, a nitrogen oxide acquisition module and a PID (proportion integration differentiation) functional module, and a timing module and a data processing module are arranged in the control module; the full-automatic control of the SNCR system can be realized, and the control of the nitrogen oxide is not over-standard or too low on the premise of controlling the nitrogen oxide to meet the environmental protection requirement; the ammonia water control mode and the nitrogen oxide control mode can be automatically switched without disturbance; according to the height of nitrogen oxides, according to the formula: the ammonia water flow set value = the ammonia water flow set value +/-ammonia water step length at the last moment, the ammonia water spraying amount is calculated, and the automatic tracking control of the nitrogen oxide is realized by automatically adjusting the ammonia water spraying amount; manual intervention is reduced, the manual adjustment times are reduced, the workload of operators is reduced, and the working efficiency is improved; the denitration efficiency is improved, the adjusting time is optimized, and the ammonia water is saved, so that the defects caused by the prior art are overcome.
Description
Technical Field
The invention relates to flue gas denitration, in particular to an SNCR denitration automatic control method and system.
Background
The importance of the process of removing nitrogen oxides from combustion fumes to prevent environmental pollution has been pointed out as a worldwide problem. The mainstream process in the world comprises the following steps: selective Catalytic Reduction (SCR) and selective non-catalytic reduction (SNCR), which are collectively referred to as selective non-catalytic reduction. These two processes are not very different except that the reaction temperature is lower than the SNCR due to the use of a catalyst for SCR. With SNCR denitration, the reductant is the largest consumable (but the catalyst is consumed in greater amounts for SCR denitration).
As shown in fig. 2, when SNCR system control operations are performed in existing cement plants (cement production line building materials, steel, electric power, petrochemical industry, etc.), operations are performed manually, and nitrogen oxide control often fails to reach standards when manual operations are performed, which causes environmental pollution.
The Chinese patent application CN201610703547 discloses an automatic control method for the spraying amount of SNCR denitration ammonia water, which aims at a Danish microliter SNCR denitration system, and has no universality, certain limitations, and poor stability and flexibility.
Chinese utility model patent CN201220185789 discloses an ammonia injection automatic control device for flue gas denitration by SNCR method, and the device structure is complicated, and the cost is relatively higher, and cement plant mostly all has the SNCR system, belongs to the repeated construction, resource-wasting.
Therefore, it is desirable to develop an automatic SNCR denitration control method and system that overcome the above-mentioned drawbacks.
Disclosure of Invention
The invention aims to solve the technical problems that the automation degree of the existing SCNR system is too low, the existing SCNR system has certain limitation, poor stability, poor flexibility and high cost, and the invention provides the SNCR denitration automatic control method which can realize the full-automatic control of the SNCR system and controls the nitrogen oxide not to exceed the standard and not to be too low on the premise of controlling the nitrogen oxide to meet the environmental protection requirement;
the ammonia water control mode and the nitrogen oxide control mode can be automatically switched without disturbance;
according to the height of nitrogen oxides, according to the formula: the ammonia water flow set value = the ammonia water flow set value +/-ammonia water step length at the last moment, the ammonia water spraying amount is calculated, and the automatic tracking control of the nitrogen oxide is realized by automatically adjusting the ammonia water spraying amount;
manual intervention is reduced, the manual adjustment times are reduced, the workload of operators is reduced, and the working efficiency is improved;
the denitration efficiency is improved, the adjusting time is optimized, and the ammonia water is saved, so that the defects caused by the prior art are overcome.
The invention also provides an SNCR denitration automatic control system.
In order to solve the technical problems, the invention provides the following technical scheme:
in a first aspect, an SNCR denitration automatic control method includes the steps of:
step 1: regulating the flow of ammonia water until the nitrogen oxide reaches the standard, and recording the amount of ammonia water used as the ammonia water quantity value V1;
step 2: judging whether an ammonia water control mode is adopted or not;
and step 3: if an ammonia water control mode is adopted, the ammonia water quantity value V1 is given to an ammonia water flow set value V0, the PID controls the ammonia water pump to adjust the flow of ammonia water according to the ammonia water flow set value V0, and the actual flow of ammonia water is recorded as a feedback value V2;
if the ammonia water control mode is not adopted, the nitrogen oxide control mode is directly adopted;
and 4, step 4: measuring the ammonia water flow at intervals by adopting a nitrogen oxide control mode, and recording the ammonia water flow as an ammonia water quantity value V3;
calculating the difference value between the set value and the actual value of the nitrogen oxide and recording the difference value as a difference value U1;
judging whether the difference value U1 is within the fluctuation range of the nitrogen oxides;
if the flow rate of the ammonia water is within the fluctuation range, the ammonia water quantity value V3 of the previous time period is given to an ammonia water flow rate set value V0, the PID controls the ammonia water pump to adjust the flow rate of the ammonia water according to the ammonia water flow rate set value V0, and the actual flow rate of the ammonia water is recorded as a feedback value V3;
if the flow rate of the ammonia water is not within the fluctuation range, calculating an ammonia water flow rate set value V0, controlling an ammonia water pump by the PID according to the ammonia water flow rate set value V0 to adjust the flow rate of the ammonia water, and recording the actual flow rate of the ammonia water as a feedback value V3;
the calculation formula is as follows: the ammonia water quantity value V3 +/-ammonia water step length = ammonia water flow set value V0 in the previous time period;
and 5: and (4) checking whether the detection time point is reached within a period of time, if so, executing the step (4), and if not, waiting for the detection time point to arrive.
The PID is called as proportional (proportion) -integral (integral) -derivative (derivative) controller, which is the most classical controller with the most extensive application in the design of automatic control system, actually an algorithm.
In the above SNCR denitration automatic control method, the initial interval time of each interval time in step 4 is 3 minutes, which can be adjusted according to the requirement.
In the above SNCR denitration automatic control method, the initial value of the fluctuation range of the nitrogen oxides in step 4 is 100, which can be adjusted according to the requirement.
In the above SNCR denitration automatic control method, the ammonia pump is a variable frequency pump.
According to the SNCR denitration automatic control method, ammonia water is adjusted according to the change of actual data of the nitric oxide, so that the nitric oxide is automatically tracked and controlled, manual intervention is effectively reduced, the fluctuation value of the nitric oxide is reduced, and the denitration efficiency is improved;
the ammonia water control mode and the nitrogen oxide control mode can be automatically selected according to the autonomy of an operator or a program, when the system starts to run, the frequency of an ammonia water pump is manually set according to the height of the nitrogen oxide to adjust the ammonia water flow value, the nitrogen oxide is controlled to reach the standard, the nitrogen oxide is switched to the automatic mode after reaching the standard and being stable, the system control adopts PID control, and a self-contained PID control function block FB41 of Siemens can be directly called;
the ammonia water control mode, the artifical aqueous ammonia flow set point that sets for, the aqueous ammonia flow upper limit that needs to set for, aqueous ammonia flow lower limit, the aqueous ammonia step length, nitrogen oxide fluctuation value, the set value that the interval time was adjusted as PID, the actual flow of aqueous ammonia is as the feedback value, the system automatically regulated aqueous ammonia flow, according to aqueous ammonia flow set point steady operation, the set value and the regulating value of aqueous ammonia should be between the flow upper limit and the aqueous ammonia flow lower limit of aqueous ammonia, carry out following step:
taking the ammonia water quantity value V1 as an ammonia water flow set value V0 to give a PID (proportion integration differentiation) regulated set value when the nitrogen oxide is regulated manually to be stable, and taking the actual flow of the ammonia water as a feedback value;
calling a PID control function block (Siemens PLC self-contained function block);
and the PID function block calculates an output value as a control value of the variable frequency pump.
The nitrogen oxide control mode is not real-time operation, and is executed once at intervals (interval time can be set, and the initial value is set to be 3 minutes), and the ammonia water flow value is calculated;
nitrogen oxide control mode, the manual setting nitrogen oxide set point, manual regulation nitrogen oxide accords with emission standard, switches to nitrogen oxide control mode again, and the automatic operation step is as follows: 1. comparing the actual value of the nitrogen oxide with the set value of the nitrogen oxide, and determining to add or subtract ammonia water on the basis of the existing ammonia water flow according to the comparison result, wherein the ammonia water flow set value = the ammonia water flow set value at the last moment +/-ammonia water step length; 2. the procedure of step 1 is executed once every a period of time, which is determined by the set interval time; 3. calling a flow control mode program, and assigning an ammonia water flow set value to a PID (proportion integration differentiation) regulated set value; 4. the process is circulated; the method comprises the following specific steps:
the first step is as follows: taking the ammonia water quantity value V1 as an ammonia water flow set value V0 to give a given value for PID adjustment when the nitrogen oxide is regulated in a manual mode to be stable, and taking the actual flow of the ammonia water as a feedback value;
the second step is that: starting an interval timer and detecting whether an actual value of the nitrogen oxide and a set value of the nitrogen oxide are in a fluctuation range of the nitrogen oxide (an initial value of the fluctuation range of the nitrogen oxide is set as 100);
the third step: in the fluctuation range of the nitrogen oxides, the actual ammonia water quantity value V3 at the last moment is given to an ammonia water flow set value V0; the nitrogen oxide fluctuation range is not calculated according to the following formula: the ammonia water flow set value = the ammonia water flow set value at the last moment +/-ammonia water step length;
the fourth step: taking the set value of the flow of the ammonia water as the set value of PID regulation, taking the actual flow of the ammonia water as a feedback value, inquiring whether the interval time reaches the set value, and if the interval time reaches the set value, starting execution from the second step, and if the interval time does not reach the set value, executing the interval time according to the original program;
the fifth step: and calling the PID to calculate an output value as a control value of the variable frequency pump.
In a second aspect, the SNCR denitration automatic control system comprises a control module, an ammonia water conveying system, a nitrogen oxide acquisition module and a PID (proportion integration differentiation) functional module, wherein a timing module and a data processing module are arranged in the control module;
the ammonia water conveying system comprises an ammonia water pump, a flowmeter and a pressure transmitter;
the ammonia water pump is used for inputting ammonia water into the denitration reaction zone to adjust the concentration of the nitrogen oxide;
the flow meter is used for recording the flow of the ammonia water, recording the flow as an ammonia water flow value and transmitting the flow to the control module;
the pressure transmitter is used for recording the pressure value of the ammonia water and transmitting the pressure value to the control module;
the flow meter and the pressure transmitter are positioned on an outlet pipeline of the ammonia water pump;
the nitrogen oxide acquisition module is used for detecting the concentration of the nitrogen oxide, receiving ammonia oxide concentration data from an environmental protection bureau on-line monitoring system, and transmitting the nitrogen oxide concentration value of the nitrogen oxide and the ammonia oxide concentration data to the control module;
the control module is used for receiving the ammonia water flow value, the nitrogen oxide concentration value and the pressure value, judging whether an ammonia water control mode or a nitrogen oxide control mode is selected, and when the ammonia water control module is selected, the control module gives the ammonia water flow value to an ammonia water flow set value and then transmits the ammonia water flow value to the PID function module;
the PID functional module is in control connection with the ammonia pump;
when the nitrogen oxide control mode is selected, the control module transmits the ammonia water flow value to the PID functional module, the PID functional module is in control connection with the ammonia water pump, and the timing module is used for timing and generating a timing result transmitted to the data processing module;
the data processing module is used for acquiring the flow value and the concentration value from the control module, combining the flow value and the concentration value with the received timing result, processing the flow value and the concentration value to generate a difference value between the set value and an actual value of the nitrogen oxide, and judging whether the difference value is in the fluctuation range of the nitrogen oxide and generating judgment data which are transmitted to the control module;
the control module gives the ammonia water flow value at the previous moment or the ammonia water flow set value +/-ammonia water step length at the previous moment to the ammonia water flow set value according to the judgment data and then transmits the ammonia water flow set value to the PID function module;
and the PID functional module is in control connection with the ammonia pump.
The above SNCR denitration automatic control system, wherein the control module is provided with a time interval determination module in a built-in manner connected to the timing module, the time interval determination module is configured to receive the timing result and determine whether timing is completed, and the control module determines whether the ammonia water flow value at the previous time or the ammonia water flow set value ± ammonia water step length at the previous time is given to the ammonia water flow set value according to whether timing is completed and then is transmitted to the PID function module.
In the above SNCR denitration automatic control system, the timing result further includes timing start data, timing interval data, and timing end data.
The SNCR denitration automatic control system is characterized in that the ammonia water pump is a variable frequency pump.
The above SNCR denitration automatic control system includes at least one processor;
a memory coupled with the at least one processor, the memory storing executable instructions, wherein the executable instructions, when executed by the at least one processor, cause the method of any of the first aspects to be implemented.
A computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, which computer program, when being executed by a processor, carries out the steps of the method of any one of the first aspects.
A chip, comprising: a processor for calling and running the computer program from the memory so that the device in which the chip is installed performs: the method of any one of the first aspect.
A computer program product comprising computer program instructions for causing a computer to perform the method of any one of the first aspects.
According to the technical scheme provided by the SNCR denitration automatic control method and the SNCR denitration automatic control system, the invention has the following technical effects:
the full-automatic control of the SNCR system can be realized, and the control of the nitrogen oxide is not over-standard or too low on the premise of controlling the nitrogen oxide to meet the environmental protection requirement;
the ammonia water control mode and the nitrogen oxide control mode can be automatically switched without disturbance;
according to the height of nitrogen oxides, according to the formula: the ammonia water flow set value = the ammonia water flow set value +/-ammonia water step length at the last moment, the ammonia water spraying amount is calculated, and the automatic tracking control of the nitrogen oxide is realized by automatically adjusting the ammonia water spraying amount;
manual intervention is reduced, the manual adjustment times are reduced, the workload of operators is reduced, and the working efficiency is improved;
the denitration efficiency is improved, the adjusting time is optimized, and the ammonia water is saved.
Compared with the Chinese patent application CN201610703547, the beneficial effects of the invention are as follows:
1. the chinese patent application CN201610703547 has certain limitations for danish microliter SNCR denitration system; the SNCR denitration automatic control method and the SNCR denitration automatic control system are suitable for various SNCR denitration systems and have stronger universality.
2. The invention has an ammonia water control mode and a nitrogen oxide control mode; because the kiln system of the cement plant has larger hysteresis quality, the nitrogen oxide reacts after a period of time after ammonia water is sprayed, so an intermittent adjustment mode is adopted (the method adopts a nitrogen oxide control mode in step 4, and the flow of the ammonia water is measured and recorded as the ammonia water quantity value V3 every a period of time), thereby avoiding frequent operation of equipment, achieving the control purpose of controlling the nitrogen oxide and being more suitable for the working condition of the cement plant; more flexible and stronger in stability.
3. The invention adopts a special calculation formula (the ammonia water quantity value V3 +/-ammonia water step length = ammonia water flow set value V0) in the last time period, can be manually and automatically switched without disturbance, has the advantages of time interval and settable ammonia water step length, is more convenient to use, can adapt to different cement kiln systems, and is more flexible.
Compared with the Chinese utility model patent CN201220185789, the invention has the advantages that:
the device of the chinese utility model patent CN201220185789 is complex in structure, relatively high in cost, and is repeatedly constructed, wasting resources. The invention is characterized in that the existing SNCR system is modified, the modification is simple, only the electrical part is required to be modified, the hardware part of the SNCR system is not modified, the cost is greatly reduced, and the use is more convenient.
Drawings
FIG. 1 is a flow chart of an SNCR denitration automatic control method of the invention;
fig. 2 is a flowchart of a conventional SNCR system.
Detailed Description
In order to make the technical means, the inventive features, the objectives and the effects of the invention easily understood and appreciated, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specific drawings, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments.
All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for matching with the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions under which the present invention can be implemented, so that the present invention has no technical significance, and any structural modification, ratio relationship change, or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention.
In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.
The first embodiment of the invention provides an SNCR denitration automatic control method and system, aiming at realizing the full-automatic control of an SNCR system, and controlling the nitrogen oxide not to exceed the standard or be too low on the premise of controlling the nitrogen oxide to meet the environmental protection requirement;
the ammonia water control mode and the nitrogen oxide control mode can be automatically switched without disturbance;
according to the height of nitrogen oxides, according to the formula: the ammonia water flow set value = the ammonia water flow set value +/-ammonia water step length at the last moment, the ammonia water spraying amount is calculated, and the automatic tracking control of the nitrogen oxide is realized by automatically adjusting the ammonia water spraying amount;
manual intervention is reduced, the manual adjustment times are reduced, the workload of operators is reduced, and the working efficiency is improved;
the denitration efficiency is improved, the adjusting time is optimized, and the ammonia water is saved.
In a first aspect, as shown in fig. 1, a first embodiment: an SNCR denitration automatic control method comprises the following steps:
step 1: regulating the flow of ammonia water until the nitrogen oxide reaches the standard, and recording the amount of ammonia water used as the ammonia water quantity value V1;
step 2: judging whether an ammonia water control mode is adopted or not;
and step 3: if an ammonia water control mode is adopted, the ammonia water quantity value V1 is given to an ammonia water flow set value V0, the PID controls the ammonia water pump to adjust the flow of ammonia water according to the ammonia water flow set value V0, and the actual flow of ammonia water is recorded as a feedback value V2;
if the ammonia water control mode is not adopted, the nitrogen oxide control mode is directly adopted;
and 4, step 4: measuring the ammonia water flow at intervals (by adopting an intermittent regulation mode) by adopting a nitrogen oxide control mode, and recording the ammonia water flow as an ammonia water quantity value V3;
calculating the difference value between the set value and the actual value of the nitrogen oxide and recording the difference value as a difference value U1;
judging whether the difference value U1 is within the fluctuation range of the nitrogen oxides;
if the flow rate of the ammonia water is within the fluctuation range, the ammonia water quantity value V3 of the previous time period is given to an ammonia water flow rate set value V0, the PID controls the ammonia water pump to adjust the flow rate of the ammonia water according to the ammonia water flow rate set value V0, and the actual flow rate of the ammonia water is recorded as a feedback value V3;
if the flow rate of the ammonia water is not within the fluctuation range, calculating an ammonia water flow rate set value V0, controlling an ammonia water pump by the PID according to the ammonia water flow rate set value V0 to adjust the flow rate of the ammonia water, and recording the actual flow rate of the ammonia water as a feedback value V3;
the calculation formula is as follows: the ammonia water quantity value V3 +/-ammonia water step length = ammonia water flow set value V0 in the previous time period;
and 5: and (4) checking whether the detection time point is reached within a period of time, if so, executing the step (4), and if not, waiting for the detection time point to arrive.
Wherein, the initial interval time of each interval of a period in the step 4 is 3 minutes, and can be adjusted according to requirements.
The fluctuation range of the nitrogen oxides in step 4 is set to 100, and may be adjusted according to the requirement.
Wherein, the ammonia pump is a variable frequency pump.
According to the SNCR denitration automatic control method, ammonia water is adjusted according to the change of actual data of the nitric oxide, so that the nitric oxide is automatically tracked and controlled, manual intervention is effectively reduced, the fluctuation value of the nitric oxide is reduced, and the denitration efficiency is improved;
the ammonia water control mode and the nitrogen oxide control mode can be automatically selected according to the autonomy of an operator or a program, when the system starts to run, the frequency of an ammonia water pump is manually set according to the height of the nitrogen oxide to adjust the ammonia water flow value, the nitrogen oxide is controlled to reach the standard, the automatic mode is switched after the nitrogen oxide reaches the standard and is stable, the system control adopts PID control, and a self-contained PID control function block FB41 of Siemens can be directly called;
the ammonia water control mode, the artifical aqueous ammonia flow set point that sets for, the aqueous ammonia flow upper limit that needs to set for, aqueous ammonia flow lower limit, the aqueous ammonia step length, nitrogen oxide fluctuation value, the set value that the interval time was adjusted as PID, the actual flow of aqueous ammonia is as the feedback value, the system automatically regulated aqueous ammonia flow, according to aqueous ammonia flow set point steady operation, the set value and the regulating value of aqueous ammonia should be between the flow upper limit and the aqueous ammonia flow lower limit of aqueous ammonia, carry out following step:
taking the ammonia water quantity value V1 as an ammonia water flow set value V0 to give a PID (proportion integration differentiation) regulated set value when the nitrogen oxide is regulated manually to be stable, and taking the actual flow of the ammonia water as a feedback value;
calling a PID control function block (Siemens PLC self-contained function block);
and the PID function block calculates an output value as a control value of the variable frequency pump.
The nitrogen oxide control mode is not real-time operation, and is executed once at intervals (interval time can be set, and the initial value is set to be 3 minutes), and the ammonia water flow value is calculated;
nitrogen oxide control mode, the manual setting nitrogen oxide set point, manual regulation nitrogen oxide accords with emission standard, switches to nitrogen oxide control mode again, and the automatic operation step is as follows: 1. comparing the actual value of the nitrogen oxide with the set value of the nitrogen oxide, and determining to add or subtract ammonia water on the basis of the existing ammonia water flow according to the comparison result, wherein the ammonia water flow set value = the ammonia water flow set value at the last moment +/-ammonia water step length; 2. the procedure of step 1 is executed once every a period of time, which is determined by the set interval time; 3. calling a flow control mode program, and assigning an ammonia water flow set value to a PID (proportion integration differentiation) regulated set value; 4. the process is circulated; the method comprises the following specific steps:
the first step is as follows: taking the ammonia water quantity value V1 as an ammonia water flow set value V0 to give a given value for PID adjustment when the nitrogen oxide is regulated in a manual mode to be stable, and taking the actual flow of the ammonia water as a feedback value;
the second step is that: starting an interval timer and detecting whether an actual value of the nitrogen oxide and a set value of the nitrogen oxide are in a fluctuation range of the nitrogen oxide (an initial value of the fluctuation range of the nitrogen oxide is set as 100);
the third step: in the fluctuation range of the nitrogen oxides, the actual ammonia water quantity value V3 at the last moment is given to an ammonia water flow set value V0; the nitrogen oxide fluctuation range is not calculated according to the following formula: the ammonia water flow set value = the ammonia water flow set value at the last moment +/-ammonia water step length;
the fourth step: taking the set value of the flow of the ammonia water as the set value of PID regulation, taking the actual flow of the ammonia water as a feedback value, inquiring whether the interval time reaches the set value, and if the interval time reaches the set value, starting execution from the second step, and if the interval time does not reach the set value, executing the interval time according to the original program;
the fifth step: and calling the PID to calculate an output value as a control value of the variable frequency pump.
Second aspect, second embodiment: an SNCR denitration automatic control system comprises a control module, an ammonia water conveying system, a nitrogen oxide acquisition module and a PID (proportion integration differentiation) functional module, wherein a timing module and a data processing module are arranged in the control module;
the ammonia water conveying system comprises an ammonia water pump, a flowmeter and a pressure transmitter;
the ammonia water pump is used for inputting ammonia water into the denitration reaction zone to adjust the concentration of the nitrogen oxide;
the flow meter is used for recording the flow of the ammonia water, recording the flow as an ammonia water flow value and transmitting the flow to the control module;
the pressure transmitter is used for recording the pressure value of the ammonia water and transmitting the pressure value to the control module;
the flow meter and the pressure transmitter are positioned on an outlet pipeline of the ammonia water pump;
the nitrogen oxide acquisition module is used for detecting the concentration of nitrogen oxide, receiving ammonia oxide concentration data from an online monitoring system of an environmental protection bureau, and transmitting the nitrogen oxide concentration value of the nitrogen oxide and the ammonia oxide concentration data to the control module;
the control module is used for receiving the ammonia water flow value, the nitric oxide concentration value and the pressure value, judging whether an ammonia water control mode or a nitric oxide control mode is selected, and when the ammonia water control module is selected, the control module gives the ammonia water flow value to an ammonia water flow set value and then transmits the ammonia water flow value to the PID function module;
the PID functional module is connected with the ammonia pump in a control way;
when a nitrogen oxide control mode is selected, the control module transmits the ammonia water flow value to the PID functional module, the PID functional module is in control connection with the ammonia water pump, and the timing module is used for timing and generating a timing result transmitted to the data processing module;
the data processing module is used for processing the flow value and the concentration value obtained from the control module and the received timing result to generate a difference value between a nitrogen oxide set value and an actual value, and is also used for judging whether the difference value is in the fluctuation range of the nitrogen oxide and generating judgment data which is transmitted to the control module;
the control module gives the ammonia water flow value at the previous moment or the ammonia water flow set value +/-ammonia water step length at the previous moment to the ammonia water flow set value according to the judgment data and then transmits the ammonia water flow set value to the PID function module;
the PID functional module is connected with the ammonia pump in a control way.
The control module is internally provided with a time interval judgment module connected with the timing module, the time interval judgment module is used for receiving a timing result and judging whether the timing is finished, and the control module is used for transmitting the ammonia water flow value at the previous moment or the ammonia water flow set value +/-ammonia water step length at the previous moment to the ammonia water flow set value or not according to whether the timing is finished or not and then transmitting the ammonia water flow set value to the PID function module.
The timing result includes timing start data, timing interval data and timing end data.
Wherein, the ammonia pump is a variable frequency pump.
Wherein, at least one processor is included;
a memory coupled with the at least one processor, the memory storing executable instructions, wherein the executable instructions, when executed by the at least one processor, cause the method of any one of the first aspects to be implemented.
A computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, which computer program, when being executed by a processor, carries out the steps of the method of any one of the first aspects.
A chip, comprising: a processor for calling and running the computer program from the memory so that the device in which the chip is installed performs: the method of any one of the first aspect.
A computer program product comprising computer program instructions for causing a computer to perform the method of any one of the first aspects.
For example, the memory may include random access memory, flash memory, read only memory, programmable read only memory, non-volatile memory or registers, or the like;
the processor may be a Central Processing Unit (CPU) or the like, or a Graphics Processing Unit (GPU) memory may store executable instructions;
the processor may execute execution instructions stored in the memory to implement the various processes described herein.
It will be appreciated that the memory in this embodiment can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory;
the non-volatile memory may be a ROM (Read-only memory), a PROM (programmable Read-only memory), an EPROM (erasable programmable Read-only memory), an EEPROM (electrically erasable programmable Read-only memory), or a flash memory.
The volatile memory may be a RAM (random access memory) which functions as an external cache;
by way of illustration and not limitation, many forms of RAM are available, such as SRAM (staticaram, static random access memory), DRAM (dynamic RAM, dynamic random access memory), SDRAM (synchronous DRAM ), DDRSDRAM (double data rate SDRAM, double data rate synchronous DRAM), ESDRAM (Enhanced SDRAM, Enhanced synchronous DRAM), SLDRAM (synchlink DRAM, synchronous link DRAM), and DRRAM (directrrambus RAM, direct memory random access memory). The memory 205 described herein is intended to comprise, without being limited to, these and any other suitable types of memory 205.
In some embodiments, the memory stores elements, upgrade packages, executable units, or data structures, or a subset thereof, or an extended set thereof: operating systems and applications;
the operating system includes various system programs, such as a framework layer, a core library layer, a driver layer, and the like, and is used for implementing various basic services and processing hardware-based tasks;
the application programs comprise various application programs and are used for realizing various application services. The program for implementing the method of the embodiment of the present invention may be included in the application program.
Those of skill in the art would understand that the elements and algorithm steps of the examples described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of software and electronic hardware;
whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the technical solution;
skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments of the present application, the disclosed system, apparatus and method may be implemented in other ways;
for example, the division of a unit or a module is only one logic function division, and there may be another division manner in actual implementation;
for example, a plurality of units or modules or components may be combined or may be integrated into another system;
in addition, functional units or modules in the embodiments of the present application may be integrated into one processing unit or module, or may exist separately and physically.
It should be understood that, in the various embodiments of the present application, the sequence numbers of the processes do not mean the execution sequence, and the execution sequence of the processes should be determined by the functions and the inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a machine-readable storage medium;
therefore, the technical solution of the present application may be embodied in the form of a software product, which may be stored in a machine-readable storage medium and may contain several instructions to cause an electronic device to execute all or part of the processes of the technical solution described in the embodiments of the present application;
the storage medium may include various media that can store program codes, such as ROM, RAM, a removable disk, a hard disk, a magnetic disk, or an optical disk.
In conclusion, the SNCR denitration automatic control method and the SNCR denitration automatic control system can realize the full-automatic control of the SNCR system, and the control of the nitric oxide is not over-standard or over-low on the premise of controlling the nitric oxide to meet the environmental protection requirement;
the ammonia water control mode and the nitrogen oxide control mode can be automatically switched without disturbance;
according to the height of nitrogen oxides, according to the formula: the ammonia water flow set value = the ammonia water flow set value +/-ammonia water step length at the last moment, the ammonia water spraying amount is calculated, and the automatic tracking control of the nitrogen oxide is realized by automatically adjusting the ammonia water spraying amount;
manual intervention is reduced, the manual adjustment times are reduced, the workload of operators is reduced, and the working efficiency is improved;
the denitration efficiency is improved, the adjusting time is optimized, and the ammonia water is saved.
Specific embodiments of the invention have been described above. It is to be understood that the invention is not limited to the particular embodiments described above, in that devices and structures not described in detail are understood to be implemented in a manner common in the art; various changes or modifications may be made by one skilled in the art within the scope of the claims without departing from the spirit of the invention, and without affecting the spirit of the invention.
Claims (8)
1. An SNCR denitration automatic control method for a cement plant is characterized by comprising the following steps:
step 1: regulating the flow of ammonia water until the nitrogen oxide reaches the standard, and recording the amount of ammonia water used as the ammonia water quantity value V1;
step 2: judging whether an ammonia water control mode is adopted or not;
and step 3: if an ammonia water control mode is adopted, the ammonia water quantity value V1 is given to an ammonia water flow set value V0, the PID controls the ammonia water pump to adjust the flow of ammonia water according to the ammonia water flow set value V0, and the actual flow of ammonia water is recorded as a feedback value V2;
if the ammonia water control mode is not adopted, the nitrogen oxide control mode is directly adopted;
and 4, step 4: measuring the ammonia water flow at intervals by adopting a nitrogen oxide control mode, and recording the ammonia water flow as an ammonia water quantity value V3;
calculating the difference value between the set value and the actual value of the nitrogen oxide and recording the difference value as a difference value U1;
judging whether the difference value U1 is within the fluctuation range of the nitrogen oxides;
if the flow rate of the ammonia water is within the fluctuation range, the ammonia water quantity value V3 of the previous time period is given to an ammonia water flow rate set value V0, the PID controls the ammonia water pump to adjust the flow rate of the ammonia water according to the ammonia water flow rate set value V0, and the actual flow rate of the ammonia water is recorded as a feedback value V3;
if the flow rate of the ammonia water is not within the fluctuation range, calculating an ammonia water flow rate set value V0, controlling an ammonia water pump by the PID according to the ammonia water flow rate set value V0 to adjust the flow rate of the ammonia water, and recording the actual flow rate of the ammonia water as a feedback value V3;
the calculation formula is as follows: the ammonia water quantity value V3 +/-ammonia water step length = ammonia water flow set value V0 in the previous time period;
the ammonia water pump is used for inputting ammonia water into the denitration reaction zone to adjust the concentration of the nitrogen oxide; the ammonia pump is a variable frequency pump; the nitrogen oxide acquisition module is used for detecting the concentration of the nitrogen oxide, receiving ammonia oxide concentration data from an environmental protection bureau on-line monitoring system and transmitting the nitrogen oxide concentration value of the nitrogen oxide and the ammonia oxide concentration data to the control module;
and 5: and (4) checking whether the detection time point is reached within a period of time, if so, executing the step (4), and if not, waiting for the detection time point to arrive.
2. The SNCR denitration automatic control method of claim 1, wherein the initial interval time of each interval time in step 4 is 3 minutes, which can be adjusted according to requirements.
3. An SNCR denitration automatic control method as set forth in claim 1 or 2, wherein the fluctuation range of the nitrogen oxides in step 4 is set to an initial value of 100, and is adjusted according to the demand.
4. An SNCR (selective non-catalytic reduction) denitration automatic control system for a cement plant is characterized by comprising a control module, an ammonia water conveying system, a nitrogen oxide acquisition module and a PID (proportion integration differentiation) functional module, wherein a timing module and a data processing module are arranged in the control module;
the ammonia water conveying system comprises an ammonia water pump, a flowmeter and a pressure transmitter;
the ammonia water pump is used for inputting ammonia water into the denitration reaction zone to adjust the concentration of the nitrogen oxide;
the flow meter is used for recording the flow of the ammonia water, recording the flow as an ammonia water flow value and transmitting the flow to the control module;
the pressure transmitter is used for recording the pressure value of the ammonia water and transmitting the pressure value to the control module;
the flow meter and the pressure transmitter are positioned on an outlet pipeline of the ammonia water pump;
the nitrogen oxide acquisition module is used for detecting the concentration of the nitrogen oxide, receiving ammonia oxide concentration data from an environmental protection bureau on-line monitoring system, and transmitting the nitrogen oxide concentration value of the nitrogen oxide and the ammonia oxide concentration data to the control module;
the control module is used for receiving the ammonia water flow value, the nitrogen oxide concentration value and the pressure value, judging whether an ammonia water control mode or a nitrogen oxide control mode is selected, and when the ammonia water control module is selected, the control module gives the ammonia water flow value to an ammonia water flow set value and then transmits the ammonia water flow value to the PID function module;
the PID functional module is in control connection with the ammonia pump;
when the nitrogen oxide control mode is selected, the control module transmits the ammonia water flow value to the PID functional module, the PID functional module is in control connection with the ammonia water pump, and the timing module is used for timing and generating a timing result transmitted to the data processing module;
the data processing module is used for acquiring the flow value and the concentration value from the control module, combining the flow value and the concentration value with the received timing result, processing the flow value and the concentration value to generate a difference value between the set value and an actual value of the nitrogen oxide, and judging whether the difference value is in the fluctuation range of the nitrogen oxide and generating judgment data which are transmitted to the control module;
the control module gives the ammonia water flow value at the previous moment or the ammonia water flow set value +/-ammonia water step length at the previous moment to the ammonia water flow set value according to the judgment data and then transmits the ammonia water flow set value to the PID function module;
the PID functional module is in control connection with the ammonia pump; the ammonia pump is a variable frequency pump.
5. The SNCR denitration automatic control system of claim 4, wherein a time interval judgment module connected with the timing module is arranged in the control module, the time interval judgment module is used for receiving the timing result and judging whether the timing is finished, and the control module gives the ammonia water flow value at the previous moment or the ammonia water flow set value at the previous moment plus or minus the ammonia water step length according to whether the timing is finished and then transmits the ammonia water flow value to the PID function module.
6. The SNCR denitration automatic control system of claim 5, wherein the timing result further comprises timing start data, timing interval data and timing end data.
7. The SNCR denitration automatic control system of claim 4, comprising at least one processor;
a memory coupled with the at least one processor, the memory storing executable instructions, wherein the executable instructions, when executed by the at least one processor, cause the method of any of claims 1-3 to be implemented.
8. A computer-readable storage medium, characterized in that a computer program is stored on the computer-readable storage medium, which computer program, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 3.
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| CN113426266A (en) * | 2021-07-16 | 2021-09-24 | 冀东水泥璧山有限责任公司 | Nitrogen oxide emission accurate control method and device based on environmental protection cost |
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