Grate-type garbage incinerator control system

Abstract

The application discloses a grate type garbage incinerator control system and relates to the technical field of garbage incineration. The system is provided with a DCS system or a PLC system and a model-based controller. The model-based controller comprises a module library, a plurality of feedback data modules and a plurality of output data modules. A plurality of sub-function modules with different functions are arranged in the module library, so that the main control system does not directly interact with the data of the incinerator equipment, but imitates the operation personnel to adjust the parameters of the DCS system or the PLC system to realize intelligent control of the garbage incinerator. Since the DCS system or the PLC system has designed sufficient logic protection for the parameter set value, the operation risk of the main control system control program is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste incineration, in particular to a control system of a grate-type waste incinerator. BACKGROUND

[0002] At present, most waste incineration power plants use manual control by operating personnel to maintain the operation of each system. This method consumes manpower, and the control quality depends on the operating level of the operating personnel, and the operating efficiency is often not high, so it is urgent to use an automatic combustion control system (ACC) of a waste incinerator to improve the degree of automation and operating efficiency.

[0003] A Chinese patent with application number 201910406450.3 discloses an ACC control method and system of a multi-drive back-pushing type waste incinerator. The system introduces a method for calculating the thickness of each section of the material layer and the combustion position according to the wind pressure and temperature of each section, and adjusts the grate speed through the thickness of the material layer and the combustion position. The control effect of the fan PID is improved through filtering of the air volume measurement value, but the specific filtering algorithm, adjustment strategy of the fan to the load change, and control method of the feed are not involved.

[0004] A Chinese patent with application number 201410116017.3 discloses an automatic combustion control system of a municipal solid waste incinerator. The system introduces a method for back-pushing the heat value of waste according to the steam volume, adjusting the amount of waste into the furnace and the air volume according to the change of the heat value, and adjusting the movement speed of the grate and the air distribution size of the primary and secondary air according to the load demand, but this method only uses a PID controller and a simple sequence control program, and it is difficult to meet the control demand when the working condition changes sharply or the load fluctuates greatly.

[0005] A Chinese patent with application number 201310175293.2 discloses an automatic combustion steam flow control system of a waste incinerator. The method uses manual setting of the target load, heat value and density of waste, and combines heat balance and material balance to derive the air volume, air distribution ratio of each section of the grate, and speed to cope with the working condition with large load change, but this method still needs to rely on the rich experience of operating personnel and a large amount of manual operation to set parameters.

[0006] Meanwhile, the existing automatic combustion control system (ACC) of the waste incinerator still has the following problems: 1. The ACC system of the waste incinerator is usually coupled with the DCS system or the PLC system in the production site, and there is a large deployment difficulty and operation risk; 2. The waste heat value is extremely unstable, and the operating condition changes in a large range, and a single control technology cannot quickly respond or easily overshoot in the case of a large change in operating condition. In addition, the same type of waste incinerator has large differences in running characteristics due to different service life, operation habits and running standards, and the same ACC system cannot adapt to different equipment; 3. The intervention action of some ACC systems cannot be compatible with the human intervention during operation, and manual intervention can only be performed after stopping the ACC; 4. Some ACC systems only perform simple filtering on part of the feedback data, and cannot obtain effective information from the feedback data; 5. Some grate-type waste incinerators are provided with turning and sliding grates, and currently, the turning and sliding grates can only rely on the sequential control program of the PLC system or the DCS system to make predetermined actions, and cannot be adjusted for special operating conditions, so as to not be able to well cope with the frequently changing operating conditions. SUMMARY

[0007] In order to solve the above technical problems, the present application provides a grate-type waste incinerator control system, comprising an incinerator device, and a master control system and a slave control system in communication with each other, the master control system comprising a plurality of independent model-based controllers,

[0008] The master control system is installed in an upper computer, and is used to obtain real-time data of the waste incinerator in operation in the slave control system according to a communication protocol, each model-based controller modifies the parameters of the control program in the slave control system by communicating the calculation results to the control points in the slave control system after operating the real-time data;

[0009] The slave control system is used to issue execution instructions to the incinerator device according to the modified parameters;

[0010] The model-based controller comprises a module library, a plurality of feedback data modules and a plurality of output data modules,

[0011] The feedback data module is in communication with the input end of the sub-function module, and is used to obtain real-time feedback data in the slave control system through a communication protocol;

[0012] The output data module is connected to the output end of the sub-function module, and is used to write the calculation results of the corresponding sub-function module into the parameter points of the slave control system through a communication protocol;

[0013] The module library comprises a plurality of sub-function modules with different functions, respectively:

[0014] The tracking increment operation module is used to query the output value from a predefined output sequence based on the index value;

[0015] The steam drum pressure change trend calculation module is used to filter out high-frequency noise in the raw data;

[0016] The air chamber pressure filtering algorithm module is used to filter out invalid air chamber pressure data and calculate the thickness of the material layer;

[0017] The main steam flow filtering and trend judgment algorithm module is used to filter out high-frequency noise in the main steam flow process value and to judge the rise and fall of the main steam flow.

[0018] The main steam flow condition judgment algorithm module is used to determine whether the main steam flow rate fluctuates within the normal allowable range;

[0019] The main steam flow control algorithm module is used to adjust the opening degree of the main combustion zone blower and the grate operation frequency according to the changing trend and speed of the main steam flow and steam drum pressure.

[0020] The feeding grate control algorithm module is used to adjust the feeding grate speed;

[0021] The controller write-value action compatible algorithm module is used to determine whether the operator has intervened in the controlled object.

[0022] The technical solution further defined in this invention is:

[0023] Furthermore, the method for creating a model-based controller includes the following steps:

[0024] S1. Create a controller page, which is used to place sub-functional modules with different functions and data connection lines for connecting each module;

[0025] S2. Drag and drop sub-functional modules from the module library to the controller page using the mouse;

[0026] S3. Connect each module with a data connection cable. The starting port of the data connection cable indicates that the data of the corresponding variable is obtained from the connected module, and the ending port of the data connection cable indicates that the data of the corresponding variable obtained above is transmitted to the corresponding variable of the module connected to the end.

[0027] S4. Set the controller's operation step size. The operation step size represents the time interval between controller executions. Every time the operation step size is reached, all modules will execute once in the order in which the data connection lines are connected.

[0028] S5. Debugging and running.

[0029] The algorithm of the tracking incremental calculation module in the aforementioned grate-type waste incinerator control system includes the following steps:

[0030] A1. Based on the input variables passed to the tracking increment calculation module via the data transmission line, determine whether the module meets the execution conditions. If not, proceed to the next step; if so, proceed to step A4.

[0031] A2. Check if the timer built into the tracking increment operation module is in the off state. If it is not in the off state, turn off the timer and set the sequence index value to 0.

[0032] A3. Within the current operation step, output 0, then execute step A7;

[0033] A4. Start the timer. If the timer is not started, start the timer. If it is already started, ignore the action of starting the timer and determine whether the timer has expired. If it has expired, proceed to the next step. If not, proceed to step A3.

[0034] A5. Increment the sequence index value by 1. If the incremented sequence index value is greater than the sequence length, set the sequence index value to 0; otherwise, proceed to the next step.

[0035] A6. Based on the incremented sequence index, retrieve the corresponding value from the sequence table and use it as the output value of the tracking increment operation module.

[0036] A7. End the calculation of the tracking increment calculation module within the current calculation step and continue to execute other sub-function modules.

[0037] The algorithm for the steam drum pressure change trend calculation module in the aforementioned grate-type waste incinerator control system includes the following steps:

[0038] B1. Within each calculation step, the steam drum pressure change trend calculation module obtains a new real-time value of the steam drum pressure;

[0039] B2. Add the real-time value of the steam drum pressure to the first queue of length n;

[0040] B3. Simultaneously, after delaying the real-time value of the steam drum pressure by m time units, add it to the second queue of length n, and one time unit is equal to one operation step.

[0041] B4. Calculate the average value fm1 of all elements in the first queue, the average value fm2 of all elements in the second queue, and the difference between the two average values ​​defm, where defm = fm1 - fm2, and output the difference defm as the rate of change of the steam drum pressure.

[0042] B5. Add the average value fm1 to the third queue of length k, and calculate the variance devi of the third queue.

[0043] B6. Add the variance devi to the fourth queue of length 6, and count the number of elements in the fourth queue that are greater than the set value Threshold, count2.

[0044] B7. Add the difference defm to the fifth queue of length 6, and calculate the number of elements greater than 0 in the fifth queue, count1.

[0045] B8. Determine if count2 is greater than 3. If it is, proceed to the next step; if it is not, output "The pressure in the steam drum remains unchanged", which is represented by the number 0 in the actual calculation.

[0046] B9. Determine if count1 is greater than 3. If it is, output "Steam drum pressure increases", which is represented by the number 1 in the actual calculation. If it is not greater, output "Steam drum pressure decreases", which is represented by the number -1 in the actual calculation.

[0047] The aforementioned control system for a grate-type waste incinerator includes the following steps in its air chamber pressure filtering algorithm module:

[0048] C1. Set the normal negative pressure range setting value of the furnace and acquire real-time data on wind chamber pressure, real-time value of furnace negative pressure, and sliding signal of sliding grate in the burnout section.

[0049] C2. When the air chamber pressure filtering algorithm module is executed for the first time, a queue Q of length n is initialized and filled with the first data.

[0050] C3. Within each calculation step, determine whether the real-time value of the furnace negative pressure is within the set value of the normal negative pressure range of the furnace, and at the same time determine whether the sliding grate of the burnout section has issued a sliding signal. If the real-time value of the furnace negative pressure is within the set value of the normal negative pressure range of the furnace, and the sliding grate of the burnout section has not issued a sliding signal, then proceed to the next step; otherwise, proceed to step C5.

[0051] C4. Add the new air chamber pressure data to the tail of queue Q and remove the data at the head of the queue, then proceed to step C6.

[0052] C5. Discard the current air chamber pressure data and keep the queue Q unchanged;

[0053] C6. Calculate the mean of queue Q and output the mean as the output value of the air chamber pressure filtering algorithm module.

[0054] The algorithm for the main steam flow filtering and trend judgment algorithm module of the aforementioned grate-type waste incinerator control system includes the following steps:

[0055] D1. Obtain the real-time value of the main steam flow rate and add the real-time value to queue Q1;

[0056] D2. Calculate the mean value of queue Q1 and output the mean value as the filtered main steam flow rate;

[0057] D3. Determine if the timer has expired. If not, retain the previous trend of main steam flow rate change; if yes, proceed to the next step.

[0058] D4. Calculate the average value fm1 of all elements in the first half of queue Q1, the average value fm2 of all elements in the second half, and the trend of main steam flow rate, where trend = fm2 - fm1.

[0059] D5. Determine whether the trend of main steam flow rate change is greater than or equal to 0. If yes, output "Main steam flow rate increases"; otherwise, output "Main steam flow rate decreases".

[0060] The algorithm for determining the main steam flow condition in the control system of the aforementioned grate-type waste incinerator includes the following steps:

[0061] E1, Set the main steam flow rate setting value Fset;

[0062] E2. Add the filtered main steam flow rate to the buffer queue Q2;

[0063] E3. Calculate the number of elements in the buffer queue Q2 that are higher than the main steam flow setpoint Fset (count1) and the number of elements that are lower than the main steam flow setpoint Fset (count2).

[0064] E4. Compare count1 and count2 with the threshold respectively. When both count1 and count2 are not greater than the threshold, output "Main steam flow is normal"; when only count1 is greater than the threshold, output "Main steam flow has been high for a long time"; when only count2 is greater than the threshold, output "Main steam flow has been low for a long time".

[0065] The main steam flow control algorithm module of the aforementioned grate-type waste incinerator control system includes the following steps:

[0066] F1. Obtain the main steam flow condition through the main steam flow condition judgment algorithm module. If the output is "the main steam flow is low for a long time", proceed to the next step; if the output is "the main steam flow is high for a long time", proceed to step F3; if the output is "the main steam flow is normal", proceed to step F4.

[0067] F2. Obtain the fan increment dFan through the tracking increment calculation module. It is a positive increment. At the same time, increase the turning frequency of the main combustion zone grate. Then execute step F6.

[0068] F3. Obtain the fan increment dFan through the tracking increment calculation module. If it is a negative increment, stop the turning action of the grate in the main combustion zone. Then execute step F6.

[0069] F4. Obtain the steam drum pressure change trend PT through the steam drum pressure change trend calculation module, and determine whether the change trend PT is "steam drum pressure unchanged". If it is, output 0 increment, blower increment dFan=0, and then execute step F6; otherwise, execute the next step.

[0070] F5. Obtain the rate of change PV of the steam drum pressure through the steam drum pressure change trend calculation module, and calculate the fan increment dFan based on this rate of change PV.

[0071] dFan=-k*PV+b

[0072] Where k and b are both coefficients, and PV represents the rate of change of steam drum pressure;

[0073] F6. Adjust the opening degree of the main combustion zone fan according to the fan increment dFan.

[0074] The aforementioned control system for a grate-type waste incinerator includes the following steps in its feeding grate control algorithm module:

[0075] G1. Real-time acquisition of the feedback value of the incinerator grate speed; calculation of the upper and lower limits of the feed grate speed constraint based on the empirical coefficient of the ratio between the feed grate speed and the incinerator grate speed.

[0076] Upper limit of feed grate speed = incinerator grate speed / a

[0077] Lower limit of feed grate speed = incinerator grate speed / b

[0078] Where a and b are both empirical coefficients;

[0079] G2. Based on the empirical values ​​of the opening degree of a unit fan and the pressure of a unit air chamber under the standard material layer thickness, obtain the normal air pressure range under the current fan opening degree.

[0080] G3. Calculate the pressure of a unit's air chamber using the air chamber pressure filtering algorithm module, and determine whether the air chamber pressure is within the normal air pressure range. If it is, output 0 increment; otherwise, proceed to the next step.

[0081] G4. Determine whether the air chamber pressure is higher or lower than the normal air pressure range. If it is higher, calculate the negative increment through the tracking increment calculation module; if it is lower, calculate the positive increment through the tracking increment calculation module.

[0082] G5. Calculate the new feeding grate speed based on the upper and lower limits of the increment and the grate speed constraints.

[0083] G6. Adjust the feeding grate speed to the new feeding grate speed.

[0084] The aforementioned control system for a grate-type waste incinerator includes the following steps in its controller write-value compatible algorithm module:

[0085] H1. At the end of the previous calculation step, the calculated output value of the model-based controller is saved to the cache value Vc, where Vc represents the record of the main controller's control actions on the controlled object.

[0086] H2. When the next operation step begins, determine whether the timer has been started. If yes, proceed to the next step; otherwise, proceed to step H6.

[0087] H3. Determine if the timer has expired. If yes, proceed to the next step; otherwise, proceed to step H5.

[0088] H4. Turn off the timer, then proceed to step H9;

[0089] H5. Increment the timer and save the feedback value Vr(n) to the cache value Vc, Vc = Vr(n). Then execute step H9.

[0090] H6. Determine whether the feedback value Vr(n) of the current write position is equal to the cached value Vc. Vr(n) represents the value of the write position read at the beginning of the operation step, i.e., the feedback value. If they are equal, proceed to step H8; if they are not equal, proceed to the next step.

[0091] H7. Start the timer, then proceed to step H9;

[0092] H8. Output the calculation result Vr(n+1) of the model-based controller to the write point, and save the value to the cache value Vc.

[0093] H9. End this round of calculation.

[0094] The beneficial effects of this invention are:

[0095] (1) In this invention, by setting up a DCS system or PLC system and a model-based controller, the model-based controller includes a module library, several feedback data modules and several output data modules. The module library is equipped with several sub-functional modules with different functions, so that the main control system does not directly interact with the incinerator equipment, but instead realizes the intelligent control of the waste incinerator by adjusting the parameters of the DCS system or PLC system, just like the way the operator adjusts the parameters of the DCS system or PLC system. Given that the DCS system or PLC system has designed sufficient logic protection for the parameter setting value, the operation risk of the main control system control program is greatly reduced.

[0096] (2) In this invention, the model-based controller design method is flexible, highly scalable, and has a short deployment and debugging cycle. The sub-functional modules contained in the module library are highly versatile and can be used as the underlying modules of more complex controllers to adapt to more complex working conditions.

[0097] (3) In this invention, the main control system containing multiple model-based controllers is an external system, which has higher security and practicality;

[0098] (4) In this invention, the main control system, which includes multiple model-based controllers, makes full use of the existing equipment and data of the waste incineration power plant. It does not require the addition of new equipment or measuring instruments, nor does it require shutdown for installation. Therefore, the hardware cost is low and the impact on actual production and operation is small. Attached Figure Description

[0099] Figure 1 This is a functional block diagram of the grate-type waste incinerator control system in an embodiment of the present invention;

[0100] Figure 2 This is a flowchart illustrating the creation of a model-based controller in an embodiment of the present invention.

[0101] Figure 3 This is a schematic diagram of the interface of the model-based controller in an embodiment of the present invention;

[0102] Figure 4 This is a flowchart of the algorithm for the tracking increment calculation module in this embodiment of the invention;

[0103] Figure 5 This is a flowchart of the algorithm for calculating the steam drum pressure change trend in an embodiment of the present invention.

[0104] Figure 6 This is a flowchart of the air chamber pressure filtering algorithm module in an embodiment of the present invention;

[0105] Figure 7 This is a flowchart of the main steam flow filtering and trend judgment algorithm module in an embodiment of the present invention;

[0106] Figure 8 This is a flowchart of the main steam flow condition judgment algorithm module in an embodiment of the present invention;

[0107] Figure 9 This is a flowchart of the main steam flow control algorithm module in an embodiment of the present invention;

[0108] Figure 10 This is a flowchart of the feeding grate control algorithm module in an embodiment of the present invention;

[0109] Figure 11 This is a flowchart of the algorithm module for the controller write-value compatibility algorithm in an embodiment of the present invention. Detailed Implementation

[0110] This embodiment provides a grate-type waste incinerator control system, including incinerator equipment, a main control system, and a slave control system. The incinerator equipment includes a feeding trolley, a sliding / tilting grate, a primary air fan, and a secondary air fan. The main control system reads and writes data to the slave control system via software communication. The main control system includes several independent model-based controllers, and the slave control system is configured as a DCS system or a PLC system.

[0111] like Figure 1 As shown, the main control system located in the host computer obtains real-time data on the operation of the waste incinerator from the DCS system or PLC system according to the communication protocol. After obtaining this feedback data, each model-based controller in the main control system performs calculations and communicates the calculation results to the control points in the DCS system or PLC system, thereby modifying the parameters of the control program in the DCS system or PLC system. The original control program of the DCS system or PLC system will issue execution instructions to the specific equipment of the incinerator according to the newly set parameters.

[0112] Therefore, the main control system designed in this invention does not directly interact with the incinerator equipment. Instead, it achieves intelligent control of the waste incinerator by mimicking the way operators adjust the parameters of the DCS or PLC system. Given that the DCS or PLC system has sufficient logic protection for the parameter settings, the operational risk of the main control system's control program is greatly reduced.

[0113] The main control system includes several independent model-based controllers. Each model-based controller comprises a module library, several feedback data modules, and several output data modules.

[0114] The feedback data module is connected to the input of the sub-functional module and is used to obtain real-time feedback data from the control system through a communication protocol.

[0115] The output data module is connected to the output end of the sub-functional module and is used to write the calculation results of the corresponding sub-functional module to the parameter location of the control system through the communication protocol.

[0116] The module library includes several sub-modules, each with different functions, namely:

[0117] The tracking increment operation module is used to query the output value from a predefined output sequence based on the index value;

[0118] The steam drum pressure change trend calculation module is used to filter out high-frequency noise in the raw data;

[0119] The air chamber pressure filtering algorithm module is used to filter out invalid air chamber pressure data and calculate the thickness of the material layer;

[0120] The main steam flow filtering and trend judgment algorithm module is used to filter out high-frequency noise in the main steam flow process value and to judge the rise and fall of the main steam flow.

[0121] The main steam flow condition judgment algorithm module is used to determine whether the main steam flow rate fluctuates within the normal allowable range;

[0122] The main steam flow control algorithm module is used to adjust the opening degree of the main combustion zone blower and the grate operation frequency according to the changing trend and speed of the main steam flow and steam drum pressure.

[0123] The feeding grate control algorithm module is used to adjust the feeding grate speed;

[0124] The controller write-value action compatible algorithm module is used to determine whether the operator has intervened in the controlled object.

[0125] like Figure 2 and Figure 3 As shown, creating a typical model-based controller includes the following steps:

[0126] S1. Create a controller page, which is used to place sub-functional modules with different functions and data connection lines for connecting each module;

[0127] S2. Drag and drop sub-functional modules from the module library to the controller page using the mouse;

[0128] S3. Connect each module with a data connection line. The combination of different sub-functional modules can flexibly build a controller with rich functions. The starting port of the data connection line indicates that the data of the corresponding variable is obtained from the connected module, and the ending port of the data connection line indicates that the data of the corresponding variable obtained above is transmitted to the corresponding variable of the module connected to the end.

[0129] S4. Set the controller's operation step size. The operation step size represents the time interval between controller executions. Every time the operation step size is reached, all modules will execute once in the order in which the data connection lines are connected.

[0130] S5. Debugging and running.

[0131] The feedback data module obtains real-time feedback data from the DCS or PLC system through a communication protocol, while the output data module writes the calculation results of the previous module to the parameter position of the DCS or PLC system through a communication protocol. The controller model constructed according to steps S1 to S5 can realize real-time monitoring of the waste incinerator.

[0132] The module library includes a tracking increment operation module. This algorithm module, as one of the sub-functional modules in the module library, can be used to build complex controller models. The core function of this module is to query the output value from a predefined output sequence based on the index value. The change of the index value is controlled by a timer. Whenever the timer ends, the index of the sequence is incremented by 1. In this way, the value in the sequence can be output according to the set sequence and the timer period. The time unit of the timer is equal to the operation step size of the controller.

[0133] like Figure 4 As shown, the specific algorithm of the tracking increment operation module is as follows: First, based on the input variable passed to the module through the data connection line, it is determined whether the module meets the execution conditions. If not, it is checked whether the module's built-in timer is in the off state. If it is not off, the timer is turned off, and the sequence index value is set to 0. Within the current calculation step, 0 is output, and the module operation within the current calculation step ends, and other modules of the controller continue to be executed. If the module meets the execution conditions, the timer is started (if the timer has already been started, the action of starting the timer is ignored), and it is determined whether the timer has expired. If not, 0 is output, and the module operation within the current calculation step ends. If the timer expires, the index value is incremented by 1 (if the incremented index value is greater than the sequence length, the index value is set to 0), and the corresponding value is retrieved from the sequence table based on the index value, which is used as the output value of the module, and the module operation within the current calculation step ends.

[0134] The line increment operation module is the smallest unit of operation, and it is usually used as a submodule of the if else conditional execution module, for example:

[0135] If the condition is met (i.e., the "execution condition" in "determine if the module meets the execution condition")

[0136] Then, the tracking increment calculation module.

[0137] The module library includes a module for calculating the trend of steam drum pressure changes. Compared with simple differential calculation, this module can effectively filter out high-frequency noise in the original data, thereby providing accurate judgment of data change trends. The core function of this module is to use mean filtering, variance calculation and threshold judgment to output three states of steam drum pressure: "steam drum pressure unchanged", "steam drum pressure increasing" and "steam drum pressure decreasing", and use them as input parameters for other modules.

[0138] This module has multiple built-in cache queues to store the module's input data and intermediate variables. During each operation cycle, the cache queue adds new values ​​to the tail of the queue and removes data from the head of the queue.

[0139] like Figure 5 As shown, the specific algorithm of the steam drum pressure change trend calculation module is as follows: Within each calculation step of the controller, the module obtains a new real-time value of the steam drum pressure and adds this value to the first queue of length n. Simultaneously, after delaying this value by m time units (1 time unit equals 1 calculation step), it adds it to the second queue of length n. Then, it calculates the average values ​​fm1 and fm2 of all elements in the first and second queues, as well as their difference defm (defm equals fm1 minus fm2). Next, fm1 is added to the third queue of length k, and the variance devi of the third queue is calculated. Then, devi is added to the fourth queue of length 6, and the number of elements in the fourth queue that are greater than the set value Threshold, count2, is determined. defm is added to the fifth queue of length 6, and the number of elements in the fifth queue that are greater than 0, count1, is determined. If count2 is less than or equal to 3, the output is "Steam drum pressure remains unchanged". If count2 is greater than 3, the output is "Steam drum pressure increases". Otherwise, the output is "Steam drum pressure decreases". In actual calculations, "constant pressure in the steam drum" is represented by the number 0, "increased pressure in the steam drum" is represented by the number 1, and "decreased pressure in the steam drum" is represented by the number -1. At the same time, defm is used as the rate of change of the steam drum pressure.

[0140] The module library includes a wind chamber pressure filtering algorithm module. During the operation of a waste incinerator, sudden changes in the induced draft fan or primary air fan can cause drastic fluctuations in wind chamber pressure. In addition, when high-temperature ash falls into the pit, the large amount of water vapor generated can also cause huge fluctuations in wind chamber pressure. As a result, the process data of wind chamber pressure is unreliable, and it is impossible to calculate the accurate material layer thickness. The wind chamber pressure filtering algorithm module can effectively filter out invalid wind chamber pressure data, obtain more accurate wind chamber pressure data, and use it to calculate the material layer thickness.

[0141] like Figure 6As shown, the specific algorithm of the air chamber pressure filtering algorithm module is as follows: When the module is executed for the first time, a queue Q of length n is initialized and filled with the first data; then, within each operation step, it is determined whether the furnace negative pressure is within the normal range (the normal range is determined by the operator's experience), and at the same time, it is determined whether the sliding grate in the burnout section has issued a sliding signal. If the furnace negative pressure is within the normal range and the sliding grate in the burnout section has not issued a sliding signal, the new air chamber pressure data is added to the tail of the queue Q, the data at the head of the queue is removed, and the average value of the queue Q is output as the output value of the module; if the furnace negative pressure is not within the normal range, or the sliding grate in the burnout section has issued a sliding signal, the current air pressure data is discarded, the queue Q is kept unchanged, and the average value of the queue Q is output as the output value of the module.

[0142] The module library includes main steam flow filtering and trend judgment algorithm modules, such as... Figure 7 As shown, in actual production, the process value of the main steam flow has high-frequency noise, which often cannot be directly used as feedback data for the controller. This module uses a mean filtering algorithm to obtain the rolling mean of the main steam flow, which serves as the feedback value for the controller. At the same time, a timer is used to periodically calculate the difference between the mean of the second half and the mean of the first half in the main steam flow buffer queue, and use it as the basis for indicating the trend of main steam flow change. If this difference is greater than or equal to 0, the output is "Main steam flow increases", otherwise the output is "Main steam flow decreases".

[0143] The module library includes a main steam flow condition judgment algorithm module. This module determines whether the main steam flow rate fluctuates within the normal allowable range. Figure 8 As shown, the specific algorithm is as follows: Add the filtered main steam flow rate to the buffer queue Q2, calculate the number of elements in the buffer queue Q2 that are higher than the main steam flow rate set value (count1) and the number of elements that are lower than the main steam flow rate set value (count2). If neither count1 nor count2 exceeds the threshold, output "Main steam flow rate is normal". If count1 exceeds the threshold, output "Main steam flow rate is too high for a long time". If count2 exceeds the threshold, output "Main steam flow rate is too low for a long time".

[0144] The module library includes a main steam flow control algorithm module. During the operation of the waste incinerator, the opening degree of the primary air fan in the main combustion zone directly regulates the main steam flow. At the same time, the frequency of grate turning can also adjust the contact between the waste and air on the grate in a short time, which is also a common method to adjust the main steam flow in a short time. The core function of the main steam flow control algorithm module is to adjust the opening degree of the main combustion zone fan and the grate turning frequency according to the changing trend and speed of the main steam flow and steam drum pressure.

[0145] like Figure 9 As shown, the specific algorithm of the main steam flow control algorithm module is as follows: The main steam flow condition is obtained by the main steam flow condition judgment algorithm module. If the main steam flow is high for a long period of time, the fan increment (negative increment) is obtained through the tracking increment calculation module, and the turning action of the main combustion zone grate is stopped. If the main steam flow is low for a long period of time, the fan increment (positive increment) is obtained through the tracking increment calculation module, and the turning frequency of the main combustion zone grate is increased. If the main steam flow is normal, the fan increment is calculated by the steam drum pressure change trend calculation module, because the steam drum pressure change trend can indicate the main steam flow change trend earlier, and the combustion condition can be adjusted in advance. When the steam drum pressure change trend is "steam drum pressure unchanged", 0 increment is output; otherwise, the fan increment dFan is calculated according to the steam drum pressure change rate (dFan=-k*PV+b, k and b are coefficients, PV represents the steam drum pressure change rate, which is calculated by the steam drum pressure change trend calculation module).

[0146] The module library contains a feeding grate control algorithm module, such as... Figure 10As shown, the specific algorithm is as follows: Based on the empirical coefficient of the ratio between the feeding grate speed and the incinerator grate speed (this empirical coefficient depends on the structural characteristics of the waste incinerator, design load, commonly used waste characteristics, and incinerator operation requirements; in most cases, this empirical coefficient is between 2 and 5), and the feedback value of the incinerator grate speed, the upper and lower limits of the feeding grate speed are calculated. The incinerator is arranged in a stepped manner from top to bottom, with the waste entering the furnace passing through units one through five sequentially from the top unit. Based on the empirical values ​​of the opening degree of the blower in unit one and the pressure of the air chamber in unit one under the standard material layer thickness (because the incinerator has different...), the upper and lower limits of the feeding grate speed are calculated. The capacity, waste characteristics, and operating conditions vary (this empirical value is usually between 200-300 Pa). The normal air pressure range under the current fan opening is obtained. The air chamber pressure filtering algorithm module calculates the pressure of one unit's air chamber. If the air chamber pressure is within the normal range, a zero increment is output; if the air chamber pressure is too high, a negative increment is calculated using the tracking increment calculation module; if the air chamber pressure is too low, a positive increment is calculated using the tracking increment calculation module. Then, based on the increments obtained in the above steps and the upper and lower limits of the feeding speed constraints, a new feeding grate speed is calculated and adjusted. The calculation formula is as follows.

[0147] newFeed = FeedPV + dFeed

[0148] If newFeed > FeedMax

[0149] newFeed=FeedMax

[0150] If newFeed <FeedMin

[0151] newFeed= FeedMin

[0152] Where dFeed represents the increment, FeedMax and FeedMin represent constraints, FeedPV represents the original feeding rate, and newFeed represents the new feeding rate.

[0153] The module library contains a controller write-value action compatible algorithm module. The core function of this module is to determine whether the operator has intervened in the controlled object (write-value point). If intervention has occurred, the controller will automatically go into hibernation for a certain period of time and then take over control again.

[0154] In a distributed control system (DCS control system, i.e., the slave controller in this article), operators modify the parameters of the controlled object through peripherals such as keyboard and mouse, thereby realizing remote control of the equipment (such as the opening degree of a fan or valve). The parameters of these controlled objects are stored in individual points of the slave controller, which are called write points.

[0155] The main controller indirectly controls the controlled object by writing the calculated value into the write position. At the same time, the operator also has control over the controlled object. To distinguish whether a control action is issued by the operator or the main controller, this invention designs a controller write action compatible algorithm module. In order to reflect the relatively higher priority of the operator, this module delays the overwriting of the operator's action command (i.e., the value of the write position). The delay is implemented by a timer. The source of the command is distinguished by comparing the cached output value with the latest real-time value of the position.

[0156] like Figure 11 As shown, the specific algorithm of the controller write-value action compatible algorithm module is as follows: At the end of the previous operation step, the module saves the calculated output value of the model-based controller to the cache value Vc, where Vc represents the record of the main controller's control action on the controlled object; at the start of the next operation step, it checks whether the timer has started. If it has not started, it checks whether the feedback value Vr(n) of the current write-value point is equal to the cache value Vc. Vr(n) represents the value read at the write-value point at the start of the operation step, i.e., the feedback value. If they are equal, it means that no human intervention has occurred, and the controller operation result is output; if they are not equal, it means that human intervention has occurred, so the timer is started and the current round of operation ends; when entering the next operation step, the timer has started, the timer is incremented, and the feedback value Vr(n) at this time is saved to the cache value Vc. If the timer expires, the timer is turned off and the current round of operation ends.

[0157] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A grate-type waste incinerator control system, comprising incinerator equipment, characterized in that: It also includes a master control system and slave control systems that are interconnected. The master control system comprises several independent model-based controllers. The main control system, installed in the host computer, is used to obtain real-time data of the waste incinerator operation from the slave control system according to the communication protocol. Each model-based controller performs calculations on the real-time data and communicates the calculation results to the control points in the slave control system to modify the parameters of the control program in the slave control system. From the control system, it is used to issue execution commands to the incinerator equipment based on the modified parameters; The model-based controller includes a module library, several feedback data modules, and several output data modules. The feedback data module is connected to the input of the sub-functional module and is used to obtain real-time feedback data from the control system through a communication protocol. The output data module is connected to the output end of the sub-functional module and is used to write the calculation results of the corresponding sub-functional module to the parameter location of the control system through the communication protocol. The module library includes several sub-modules, each with different functions, namely: The tracking increment operation module is used to query the output value from a predefined output sequence based on the index value; The steam drum pressure change trend calculation module is used to filter out high-frequency noise in the raw data. It uses mean filtering, variance calculation and threshold judgment to output three states of steam drum pressure: "steam drum pressure unchanged", "steam drum pressure increasing" and "steam drum pressure decreasing", and uses them as input parameters for other modules. The air chamber pressure filtering algorithm module is used to filter out invalid air chamber pressure data and calculate the thickness of the material layer; The main steam flow filtering and trend judgment algorithm module is used to filter out high-frequency noise in the main steam flow process value and to judge the rise and fall of the main steam flow. The main steam flow condition judgment algorithm module is used to determine whether the main steam flow rate fluctuates within the normal allowable range; The main steam flow control algorithm module is used to adjust the opening degree of the main combustion zone blower and the grate operation frequency according to the changing trend and speed of the main steam flow and steam drum pressure. The feeding grate control algorithm module is used to adjust the feeding grate speed; The controller write-value action compatible algorithm module is used to determine whether the operator has intervened in the controlled object; The algorithm of the main steam flow control algorithm module includes the following steps. F1. Obtain the main steam flow condition through the main steam flow condition judgment algorithm module. If the output is "Main steam flow is low for a long time", proceed to the next step; if the output is "Main steam flow is high for a long time", proceed to step F3; if the output is "Main steam flow is normal", proceed to step F4. F2. Obtain the fan increment dFan through the tracking increment calculation module. It is a positive increment. At the same time, increase the turning frequency of the main combustion zone grate. Then execute step F6. F3. Obtain the fan increment dFan through the tracking increment calculation module. If it is a negative increment, stop the turning action of the grate in the main combustion zone. Then execute step F6. F4. Obtain the steam drum pressure change trend PT through the steam drum pressure change trend calculation module, and determine whether the change trend PT is "steam drum pressure unchanged". If it is, output 0 increment, blower increment dFan=0, and then execute step F6; otherwise, execute the next step. F5. Obtain the rate of change PV of the steam drum pressure through the steam drum pressure change trend calculation module, and calculate the fan increment dFan based on this rate of change PV. dFan=-k*PV+b Where k and b are both coefficients, and PV represents the rate of change of steam drum pressure; F6. Adjust the opening degree of the main combustion zone fan according to the fan increment dFan.

2. The control system for a grate-type waste incinerator according to claim 1, characterized in that: The method for creating the model-based controller includes the following steps: S1. Create a controller page, which is used to place sub-functional modules with different functions and data connection lines for connecting each module; S2. Drag and drop sub-functional modules from the module library to the controller page using the mouse; S3. Connect each module with a data connection cable. The starting port of the data connection cable indicates that the data of the corresponding variable is obtained from the connected module, and the ending port of the data connection cable indicates that the data of the obtained corresponding variable is transmitted to the corresponding variable of the connected module. S4. Set the controller's operation step size. The operation step size represents the time interval between controller executions. Every time the operation step size is reached, all modules will execute once in the order in which the data connection lines are connected. S5. Debugging and running.

3. The control system for a grate-type waste incinerator according to claim 1, characterized in that: The algorithm of the tracking increment calculation module includes the following steps: A1. Based on the input variables passed to the tracking increment calculation module via the data transmission line, determine whether the module meets the execution conditions. If not, proceed to the next step; if so, proceed to step A4. A2. Check if the timer built into the tracking increment operation module is in the off state. If it is not in the off state, turn off the timer and set the sequence index value to 0. A3. Within the current operation step, output 0, then execute step A7; A4. Start the timer. If the timer is not started, start the timer. If it is already started, ignore the action of starting the timer and determine whether the timer has expired. If it has expired, proceed to the next step. If not, proceed to step A3. A5. Increment the sequence index value by 1. If the incremented sequence index value is greater than the sequence length, set the sequence index value to 0; otherwise, proceed to the next step. A6. Based on the incremented sequence index, retrieve the corresponding value from the sequence table and use it as the output value of the tracking increment operation module. A7. End the calculation of the tracking increment calculation module within the current calculation step and continue to execute other sub-function modules.

4. The control system for a grate-type waste incinerator according to claim 1, characterized in that: The algorithm of the steam drum pressure change trend calculation module includes the following steps: B1. Within each calculation step, the steam drum pressure change trend calculation module obtains a new real-time value of the steam drum pressure; B2. Add the real-time value of the steam drum pressure to the first queue of length n; B3. Simultaneously, after delaying the real-time value of the steam drum pressure by m time units, add it to the second queue of length n, and one time unit is equal to one operation step. B4. Calculate the average value fm1 of all elements in the first queue, the average value fm2 of all elements in the second queue, and the difference between the two average values ​​defm, where defm = fm1 - fm2, and output the difference defm as the rate of change of the steam drum pressure. B5. Add the average value fm1 to the third queue of length k, and calculate the variance devi of the third queue. B6. Add the variance devi to the fourth queue of length 6, and count the number of elements in the fourth queue that are greater than the set value Threshold, count2. B7. Add the difference defm to the fifth queue of length 6, and calculate the number of elements greater than 0 in the fifth queue, count1. B8. Determine if count2 is greater than 3. If it is, proceed to the next step. If it is not greater than, output "steam drum pressure remains unchanged", which is represented by the number 0 in the actual calculation process; B9. Determine if count1 is greater than 3. If it is, output "The pressure in the steam drum has increased". In actual calculation, this is represented by the number 1. If the value is not greater than the specified value, the output will be "pressure drop in steam drum", which is represented by the number -1 in the actual calculation.

5. The control system for a grate-type waste incinerator according to claim 1, characterized in that: The algorithm of the air chamber pressure filtering algorithm module includes the following steps: C1. Set the normal negative pressure range setting value of the furnace and acquire real-time data on wind chamber pressure, real-time value of furnace negative pressure, and sliding signal of sliding grate in the burnout section. C2. When the air chamber pressure filtering algorithm module is executed for the first time, a queue Q of length n is initialized and filled with the first data. C3. Within each calculation step, determine whether the real-time value of the furnace negative pressure is within the set value of the normal negative pressure range of the furnace, and at the same time determine whether the sliding grate of the burnout section has issued a sliding signal. If the real-time value of the furnace negative pressure is within the set value of the normal negative pressure range of the furnace, and the sliding grate of the burnout section has not issued a sliding signal, then proceed to the next step; otherwise, proceed to step C5. C4. Add the new air chamber pressure data to the tail of queue Q and remove the data at the head of the queue, then proceed to step C6. C5. Discard the current air chamber pressure data and keep the queue Q unchanged; C6. Calculate the mean of queue Q and output the mean as the output value of the air chamber pressure filtering algorithm module.

6. The control system for a grate-type waste incinerator according to claim 1, characterized in that: The algorithm of the main steam flow filtering and trend judgment algorithm module includes the following steps: D1. Obtain the real-time value of the main steam flow rate and add the real-time value to queue Q1; D2. Calculate the mean value of queue Q1 and output the mean value as the filtered main steam flow rate; D3. Determine if the timer has expired. If not, retain the previous trend of main steam flow rate change; if yes, proceed to the next step. D4. Calculate the average value fm1 of all elements in the first half of queue Q1, the average value fm2 of all elements in the second half, and the trend of main steam flow rate, where trend = fm2 - fm1. D5. Determine whether the trend of main steam flow rate change is greater than or equal to 0. If yes, output "Main steam flow rate increases"; otherwise, output "Main steam flow rate decreases".

7. The control system for a grate-type waste incinerator according to claim 1, characterized in that: The algorithm for determining the main steam flow condition includes the following steps. E1, Set the main steam flow rate setting value Fset; E2. Add the filtered main steam flow rate to the buffer queue Q2; E3. Calculate the number of elements in the buffer queue Q2 that are higher than the main steam flow setpoint Fset (count1) and the number of elements that are lower than the main steam flow setpoint Fset (count2). E4. Compare count1 and count2 with the threshold respectively. When both count1 and count2 are not greater than the threshold, output "Main steam flow is normal"; when only count1 is greater than the threshold, output "Main steam flow has been high for a long time"; when only count2 is greater than the threshold, output "Main steam flow has been low for a long time".

8. The control system for a grate-type waste incinerator according to claim 1, characterized in that: The algorithm of the feeding grate control algorithm module includes the following steps: G1. Real-time acquisition of the feedback value of the incinerator grate speed; calculation of the upper and lower limits of the feed grate speed constraint based on the empirical coefficient of the ratio between the feed grate speed and the incinerator grate speed. Upper limit of feed grate speed = incinerator grate speed / a Lower limit of feed grate speed = incinerator grate speed / b Where a and b are both empirical coefficients; G2. Based on the empirical values ​​of the opening degree of a unit fan and the pressure of a unit air chamber under the standard material layer thickness, obtain the normal air pressure range under the current fan opening degree. G3. Calculate the pressure of a unit's air chamber using the air chamber pressure filtering algorithm module, and determine whether the air chamber pressure is within the normal air pressure range. If it is, output 0 increment; otherwise, proceed to the next step. G4. Determine whether the air chamber pressure is higher or lower than the normal air pressure range. If it is higher, calculate the negative increment through the tracking increment calculation module; if it is lower, calculate the positive increment through the tracking increment calculation module. G5. Calculate the new feeding grate speed based on the upper and lower limits of the increment and the grate speed constraints. G6. Adjust the feeding grate speed to the new feeding grate speed.

9. The control system for a grate-type waste incinerator according to claim 1, characterized in that: The algorithm of the controller write-value compatible algorithm module includes the following steps: H1. At the end of the previous calculation step, the calculated output value of the model-based controller is saved to the cache value Vc, where Vc represents the record of the main controller's control actions on the controlled object. H2. When the next operation step begins, determine whether the timer has been started. If yes, proceed to the next step; otherwise, proceed to step H6. H3. Determine if the timer has expired. If yes, proceed to the next step; otherwise, proceed to step H5. H4. Turn off the timer, then proceed to step H9; H5. Increment the timer and save the feedback value Vr(n) to the cache value Vc, Vc = Vr(n). Then execute step H9. H6. Determine whether the feedback value Vr(n) of the current write position is equal to the cached value Vc. Vr(n) represents the value of the write position read at the beginning of the operation step, i.e., the feedback value. If they are equal, proceed to step H8; if they are not equal, proceed to the next step. H7. Start the timer, then proceed to step H9; H8. Output the calculation result Vr(n+1) of the model-based controller to the write point, and save the value to the cache value Vc. H9. End this round of calculation.

Images