Reciprocating mechanical grate furnace and its motion control method

Abstract

The present application relates to solid waste treatment technical field, especially a reciprocating mechanical grate furnace and its motion control method, the grate is arranged along the length direction of the furnace body, forming a ladder type combustion area, the two ends of the sliding grate are equipped with oil cylinders, each oil cylinder is connected with a proportional valve and a stop valve, and each oil cylinder is internally provided with a displacement transmitter; the input end of the proportional valve is connected with the output end of an incremental PID control module, the opening of the proportional valve is adjusted through the control increment output by the incremental PID control module, thereby realizing accurate control of the controlled parameters; the grate is alternately composed of multiple sliding grates and multiple fixed grates, and the reciprocating motion of each sliding grate is driven by two oil cylinders arranged outside the furnace; through improvement of the mechanical structure of the equipment and the matching motion control method, stable, efficient and energy-saving operation of the grate is realized, the frequency of manual intervention of the operation personnel and the maintenance cost are reduced, and the overall performance of the equipment is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid waste treatment, and particularly relates to a reciprocating mechanical grate furnace and a motion control method thereof. BACKGROUND

[0002] Garbage incineration power generation is an effective way to dispose of garbage in a harmless, reduced and resourceful manner. Garbage incineration treatment not only has an environmental protection effect, but also produces steam for power generation and heat supply by using the waste heat of garbage incineration, thereby saving energy and being a better resource recycling mode.

[0003] The reciprocating mechanical grate furnace is a most commonly used grate incineration technology in a municipal solid waste incineration power plant. The reciprocating mechanical grate furnace conveys, stirs and turns garbage through reciprocating movement of grate pieces to realize full combustion of the garbage.

[0004] The reciprocating mechanical grate furnace is the most widely used garbage incineration treatment technology in China at present. In garbage incineration furnaces and other equipment, the reciprocating grate is a key component, and its driving mode directly affects the combustion efficiency, equipment stability and labor intensity of operating personnel. The traditional reciprocating grate driving mode has problems such as unstable power transmission, high frequency of manual intervention and complex maintenance. SUMMARY

[0005] The technical problem to be solved by the present application is that in order to solve the problems existing in the prior art in the background, a reciprocating mechanical grate furnace and a motion control method thereof are provided, which realize stable, efficient and energy-saving operation of the grate, reduce the frequency of manual intervention of operating personnel, reduce maintenance cost and improve overall performance of the equipment.

[0006] The technical scheme adopted by the present application to solve the technical problem is that a reciprocating mechanical grate furnace comprises

[0007] An incineration furnace is used for burning waste and generating heat;

[0008] A grate is arranged along the length direction of the furnace body of the incineration furnace to form a stepped combustion area, and comprises multiple levels of sliding grates and multiple levels of fixed grates arranged alternately. Oil cylinders are installed at both ends of the sliding grates to synchronously drive the reciprocating movement of the sliding grates. Proportional valves and stop valves are connected to each oil cylinder, and displacement transmitters are built-in each oil cylinder.

[0009] An incremental PID control module is stored in the form of a program in the memory of a controller hardware platform and is executed by a processor in the controller hardware platform. The incremental PID control module is used to periodically calculate and output a control increment signal according to the deviation between a feedback signal and a set value. The input end of the proportional valve is connected to the output end of the incremental PID control module. The opening degree of the proportional valve is adjusted by the control increment output by the incremental PID control module, so as to realize accurate control of the controlled parameter.

[0010] The single-stage grate is synchronously driven by the two-end oil cylinder, and combined with the incremental PID double-channel independent control, the grate piece is uniformly stressed and smoothly moved, which significantly reduces the mechanical wear and failure rate, prolongs the service life of the grate and oil cylinder, and reduces the maintenance cost and downtime.

[0011] Further, the overall reciprocating movement speed of the grate is a reference speed , and the speed coefficient of each sliding grate ranges from 0% to 100%. In the automatic mode, the unit speed of the actual reciprocating movement of the single-stage sliding grate is controlled by adjusting to differentiate the speed of each stage of the grate to adjust the distribution of the garbage on the grate bed, thereby optimizing the combustion process, and the independently adjustable speed coefficient of each grate allows the operator to accurately control the rolling and advancing speed of the garbage according to the garbage composition, calorific value and different positions in the combustion section, ensuring that the garbage has the best residence time in the drying, combustion and burnout stages, achieving more complete combustion, improving the incineration efficiency, reducing the ignition loss of the ash and reducing harmful substances due to incomplete combustion.

[0012] Further, the movement control mode of the grate is divided into a manual mode and an automatic mode.

[0013] A reciprocating grate movement control method, comprising a reciprocating mechanical grate furnace as claimed in any one of the preceding claims, and the specific steps are as follows:

[0014] Step 1: Start, enter manual mode and automatic mode selection, and execute the corresponding control logic according to the current mode during operation, and output the proportional valve control signal;

[0015] Step 2: If the manual mode is entered, the manual instruction is received, the sliding grate is set according to the manual given opening MVAL value, and the corresponding instruction is executed;

[0016] Step 3: If the automatic mode is entered, and the enable signal EN is TRUE, the automatic cycle is executed, the oil cylinder first drives the sliding grate to retreat to the retreat position, stays for 1-2s after retreating to the position, and then switches to the forward movement; stays for 1-2s after advancing to the position, and then switches to the retreat movement;

[0017] Step 4: If the automatic mode is entered, and the enable signal EN is FALSE, then the standby state is entered, and the manual mode and automatic mode selection are performed again in step 1.

[0018] Further, when the automatic mode is running, the control of the proportional valve includes the following steps:

[0019] Initial value setting, when the sliding grate automatic mode is started and every time the position is reversed, the initial value of the calculated output value LOP of the left proportional valve and the calculated output value ROP of the right proportional valve is determined by table lookup or linear mapping, so that better and faster speed response can be obtained at the start or reversal;

[0020] Incremental adjustment, during the sliding movement, the left and right proportional valves are independently adjusted by the incremental PID control module, the left and right proportional valves calculate the left proportional valve adjustment increment OPIVL and the right proportional valve adjustment increment OPIVR according to the respective stroke deviation, the formula is:

[0021] ;

[0022] ;

[0023] Wherein, TS = TM_CYCLE / 1000, XP, TI, TD are debugging setting values;

[0024] TM_CYCLE: DCS scanning period; : left proportional valve adjustment increment; : right proportional valve adjustment increment; : left cylinder stroke deviation; : last cycle left cylinder stroke deviation; : last but one cycle left cylinder stroke deviation; : right cylinder stroke deviation; : last cycle right cylinder stroke deviation; : last but one cycle right cylinder stroke deviation;

[0025] Step c: output update, use the adjustment increment calculated in the current cycle to update the calculated output value LOP of the left proportional valve and the calculated output value ROP of the right proportional valve in the last cycle, the formula is:

[0026] The calculated output value of the proportional valve in the current cycle = the calculated output value of the proportional valve in the last cycle + the adjustment increment in the current cycle.

[0027] Further, when the manual mode is switched to the automatic mode, the automatic mode is initialized to ensure that the automatic cycle starts from the correct starting point, and smooth and impact-free switching between manual and automatic modes is realized, the specific steps are as follows:

[0028] Step A: position detection and reset, detect the starting position of the sliding grate, if the starting position of the sliding grate is not the position of the backward to the position, then the sliding grate is controlled to retreat to the position of the backward to the position and then advance;

[0029] Step B: Desired stroke calculation, get left cylinder position feedback LFB and right cylinder position feedback RFB; take the larger value as the initial value; calculate the desired stroke: ;

[0030] CYCLET_C = max(LFB, RFB) * (LEN / max(LFB, RFB))

[0031] Step C: Synchronous control execution, automatically adjust the oil supply rate of the two proportional valves, drive the two side cylinders to move according to the desired stroke CYCLET_C.

[0032] Further, when the automatic mode is running, the cylinder stroke deviation calculation:

[0033] When automatic forward:

[0034] Left cylinder stroke deviation ;

[0035] Right cylinder stroke deviation ;

[0036] When automatic backward:

[0037] Left cylinder stroke deviation ;

[0038] Right cylinder stroke deviation ;

[0039] Wherein, : Left cylinder stroke deviation; : Last cycle left cylinder stroke deviation; , is a percentage, which is the deviation rate of the actual cylinder stroke and the desired stroke; the value is greater than zero, indicating that the actual cylinder stroke lags behind; the value is less than zero, indicating that the actual cylinder stroke is ahead of schedule;

[0040] , : Last cycle left and right cylinder stroke deviation;

[0041] , : Last last cycle left and right cylinder stroke deviation.

[0042] Further, step 3, slide grate in place signal judgment:

[0043] Retreat to the left cylinder position feedback , and the right cylinder position feedback ;

[0044] Advance to position, left cylinder position feedback , and right cylinder position feedback ;

[0045] Wherein, LEN: the maximum stroke of the sliding grate, is the set retreat to position tolerance threshold, is the set advance to position tolerance threshold.

[0046] Further, the analog output AO of the proportional valve in the automatic mode is controlled as follows:

[0047] When advancing automatically:

[0048] The left proportional valve output value LAO = 50.0 + LOP / 2.0;

[0049] The right proportional valve output value RAO = 50.0 + ROP / 2.0;

[0050] When retreating automatically:

[0051] The left proportional valve output value LAO = 50.0 - LOP / 2.0;

[0052] The right proportional valve output value RAO = 50.0 - ROP / 2.0.

[0053] Further, the analog output AO of the proportional valve in the manual mode is controlled as follows:

[0054] When advancing manually:

[0055] The left proportional valve output value LAO = 50.0 + CMD_MVAL / 2.0;

[0056] The right proportional valve output value RAO = 50.0 + CMD_MVAL / 2.0;

[0057] When retreating manually:

[0058] The left proportional valve output value LAO = 50.0 - CMD_MVAL / 2.0;

[0059] The right proportional valve output value RAO = 50.0 - CMD_MVAL / 2.0;

[0060] When stopping manually:

[0061] The left proportional valve output value LAO = 50.0;

[0062] The right proportional valve output value RAO = 50.0;

[0063] Wherein, 50.0: the middle reference value of the proportional valve; CMD_MVAL: the manual speed command value.

[0064] Further, in the manual mode and the automatic mode, the stroke deviation of the left and right oil cylinders is calculated in real time when the sliding grate moves , the formula is: ;

[0065] The alarm triggering condition is: , or ;

[0066] The alarm clearing condition is: ;

[0067] Wherein, LFB: the position feedback (mm) of the left oil cylinder; RFB: the position feedback (mm) of the right oil cylinder; : the lower limit value of the alarm triggering; : the upper limit value of the alarm triggering; : the lower limit value of the alarm clearing; : the upper limit value of the alarm clearing.

[0068] The alarm triggering and clearing adopt different threshold values to form a hysteresis control, which avoids frequent triggering and clearing of the alarm due to slight signal fluctuation near the alarm critical point, prevents unnecessary interruption of the production process, and improves the continuous operation capability

[0069] Further, when any one of the following conditions is met, the left stop valve LSV and the right stop valve RSV are simultaneously opened: the stop valve meets any one of the manual forward, the manual backward or the automatic mode, and the enable signal EN is TRUE;

[0070] When any one of the following conditions is met, the left stop valve LSV and the right stop valve RSV are simultaneously closed: the stop valve meets any one of the manual stop, the automatic mode, the enable signal EN is FALSE, the left oil cylinder position feedback LFB signal is bad, the right oil cylinder position feedback RFB signal is bad, or the hydraulic system pressure feedback value is too low or too high;

[0071] When the left and right oil cylinder stroke deviation alarm flag is triggered, according to the size relationship between the left oil cylinder position feedback value LFB and the right oil cylinder position feedback value RFB, the unilateral stop valve is closed; and the closing signal of the stop valve has higher priority than the opening signal of the stop valve.

[0072] The beneficial effects of the present application are:

[0073] 1) The reciprocating grate furnace of the present application comprises multiple stages of sliding grates and multiple stages of fixed grates arranged alternately, and the reciprocating movement of each stage of sliding grates is driven by two oil cylinders arranged outside the furnace on both sides; by improving the mechanical structure of the equipment and the matching motion control method, stable, efficient and energy-saving operation of the grate is realized, the frequency of manual intervention of the operator is reduced, the maintenance cost is reduced, and the overall performance of the equipment is improved;

[0074] 2) Single-stage grate speed and stroke high-precision regulation is realized by closed-loop control of proportional valve and displacement transducer and by means of incremental PID regulation mode;

[0075] 3) Independent regulation of global reference speed and single-stage speed coefficient, adaptation to combustion characteristics of different fuels, flexible adjustment;

[0076] 4) Balanced stress is ensured by double-oil-cylinder driving, system stability is improved by cut-off valve and displacement overrun protection, and safety and reliability are ensured;

[0077] 5) Incremental PID algorithm is used to calculate proportional valve regulation increment in automatic mode, thereby greatly improving the synchronization of the motion of the two oil cylinders;

[0078] 6) Incremental PID regulation and cut-off valve control are combined to improve the synchronization and stability of the motion of the oil cylinder. BRIEF DESCRIPTION OF DRAWINGS

[0079] The present application will be further described below in conjunction with the drawings and embodiments.

[0080] Figure 1 is a structural schematic diagram of the reciprocating mechanical grate furnace of the present application;

[0081] Figure 2 is a control flowchart of the present application;

[0082] In the figure: 1. sliding grate, 2. oil cylinder, 3. proportional valve, 4. cut-off valve, 5. displacement transducer, 6. incremental PID control module. DETAILED DESCRIPTION

[0083] The present application will now be further described in conjunction with the drawings. These drawings are all simplified schematic diagrams, and only illustrate the basic structure of the present application in a schematic manner, and thus only show the configurations related to the present application.

[0084] As shown in a reciprocating mechanical grate furnace, the motion control mode of the grate is divided into manual mode and automatic mode, including Figure 1

[0085] incinerator for burning waste and generating heat;

[0086] grate arranged along the length direction of the incinerator body to form a stepped combustion area, including multiple stages of sliding grates 1 and multiple stages of fixed grates arranged alternately, the fixed grate being fixedly installed on the body support to support the fuel and guide the combustion gas flow; the sliding grate 1 is driven by the liquid oil cylinder 2 to make reciprocating motion above the fixed grate, to realize pushing and stirring of the fuel, and the adjacent fixed grate and the sliding grate 1 form an independent unit;

[0087] ​Hydraulic cylinders 2 are installed at both ends of the sliding grate 1 to synchronously drive the sliding grate 1 to reciprocate. Therefore, the reference speed of the entire grate and the speed coefficient of the single-stage sliding grate 1 can be independently adjusted to adapt to the combustion characteristics of different fuels (such as municipal solid waste, biomass, and industrial solid waste). At the same time, the two hydraulic cylinders 2 are symmetrically arranged to synchronously drive the sliding grate 1 to reciprocate. The dual hydraulic cylinders 2 drive ensures balanced force. Each hydraulic cylinder 2 is connected to a proportional valve 3 and a shut-off valve 4. The proportional valve 3 controls the direction of the oil circuit (forward / reverse oil supply) and the flow rate (opening degree), corresponding to an electrical signal of 4~20mA.

[0088] 12~20mA: Forward oil supply, the oil cylinder extends (pushing material), 20mA corresponds to the maximum opening of the forward oil supply;

[0089] 4~12mA: Reverse oil supply, cylinder retracts (resets), 4mA corresponds to the maximum reverse oil supply opening;

[0090] In an emergency, the shut-off valve 4 cuts off the oil circuit to prevent the hydraulic system from overloading or the grate from going out of control, thus playing a safety protection role. At the same time, during operation, the shut-off valve 4 assists the proportional valve 3 to improve the synchronicity of the movement of the left and right oil cylinders 2.

[0091] Each cylinder 2 is equipped with a built-in displacement transmitter 5, which provides real-time feedback on the piston rod displacement in cylinder 2. The zero point (full retraction) corresponds to 4mA, and the full scale (greater than or equal to the full extension of the piston rod) corresponds to 20mA. This is used for closed-loop control to ensure the accuracy of the grate stroke.

[0092] The over-limit protection of the shut-off valve 4 and the displacement transmitter 5 improves the stability of the system.

[0093] The incremental PID control module 6 is stored in the memory of the controller hardware platform in the form of an execution program and is executed by the processor in the controller hardware platform. It is used to periodically calculate and output a control increment signal based on the deviation between the feedback signal and the set value. The input end of the proportional valve 3 is connected to the output end of the incremental PID control module 6. The opening of the proportional valve 3 is adjusted by the control increment output by the incremental PID control module 6, thereby realizing the precise control of the controlled parameter.

[0094] High-precision regulation of single-stage grate speed and stroke is achieved through closed-loop control of proportional valve 3 and displacement transmitter 5, and by incremental PID adjustment using incremental PID control module 6.

[0095] The overall reciprocating speed of the grate is the reference speed. The speed coefficient of each sliding grate 1 , The value range is 0% to 100%, which is the unit speed of the actual reciprocating motion of the single-stage sliding grate 1. , so that the whole movement speed of the double mechanical grate furnace can be adjusted conveniently, and the single-stage grate movement speed can be adjusted conveniently.

[0096] The main signals involved in the control mode are:

[0097] The input signals are mainly collected from the field in real time and input by the man-machine interface, including LFB left cylinder position feedback (mm), RFB right cylinder position feedback (mm), SPEED unit speed (mm / s), MVAL manual opening degree (%), EN enable signal, TM_CYCLE DCS scanning period (ms);

[0098] The output signals are used for the output to the control device, and the state of the feedback stage sliding unit. The state word W_STATE is used to package various state signals of the stage sliding unit, so as to facilitate the historical database collection and archiving, including LSV left stop valve command signal, RSV side stop valve command signal, LAO left proportional valve AO output value, RAO right proportional valve AO output value, STA_ALM left and right cylinder stroke deviation alarm flag, W_STATE state word, mainly including movement mode, movement direction, in-place state, alarm information, etc.

[0099] The command signals are derived from the man-machine interface, and are used to issue the operation instructions of the operator. The command signals can be issued alone or in the form of a control word, including CMD_MFWD manual forward command, CMD_MBK manual backward command, CMD_MSP manual stop command, and CMD_AUTO automatic mode command.

[0100] The internal variables are mainly used for internal computer data temporary storage, including CYCLET_C expected stroke, LEN maximum stroke of the sliding grate, left proportional valve adjustment increment, right proportional valve adjustment increment, LOP calculated output value of the left proportional valve, ROP calculated output value of the right proportional valve, left cylinder stroke deviation, right cylinder stroke deviation, last cycle left cylinder stroke deviation, last cycle right cylinder stroke deviation, last last cycle left cylinder stroke deviation, last last cycle right cylinder stroke deviation, left and right cylinder stroke deviation.

[0101] AO (Analog Output) is to output continuous signal (such as 4-20mA, 0-10V) to control the device that needs continuous adjustment (such as the opening of proportional valve, the speed of frequency converter, the power of heater, etc.).

[0102] As shown in Figure 2 A reciprocating grate movement control method, comprising a reciprocating mechanical grate furnace as described above, the specific steps are as follows:

[0103] Step 1: system startup, enter manual mode and automatic mode selection, the system will execute the corresponding control logic according to the current mode during operation, and output proportional valve 3 control signal, in automatic mode, the system will automatically adjust the proportional valve 3 output according to the position feedback, to ensure that the grate moves accurately according to the set speed and stroke;

[0104] Step 2: if it is in manual mode, receive manual instruction, manual mode includes manual forward instruction CMD_MFWD, manual backward instruction CMD_MBK, manual stop instruction CMD_MSP, and manual given opening MVAL. The oil supply rate of the two proportional valves 3 is determined according to the manual given opening MVAL setting value, and then the forward and backward movement speed is controlled. Specifically: if it is in manual mode, receive manual instruction, if the instruction is manual forward instruction CMD_MFWD, according to the manual given opening MVAL setting value, the sliding grate 1 executes the forward instruction;

[0105] If the instruction is manual backward instruction CMD_MBK, according to the manual given opening MVAL setting value, the sliding grate 1 executes the backward instruction;

[0106] If the instruction is manual stop instruction CMD_MSP, according to the manual given opening MVAL setting value, the sliding grate 1 executes the stop movement instruction;

[0107] AO output of proportional valve 3 in manual mode:

[0108] When manual forward:

[0109] The AO output value of the left proportional valve LAO=50.0+CMD_MVAL / 2.0;

[0110] The AO output value of the right proportional valve RAO=50.0+CMD_MVAL / 2.0;

[0111] When manual backward:

[0112] The AO output value of the left proportional valve LAO=50.0-CMD_MVAL / 2.0;

[0113] The AO output value of the right proportional valve RAO=50.0-CMD_MVAL / 2.0;

[0114] Manual stop:

[0115] The AO output value of the left proportional valve LAO = 50.0;

[0116] The AO output value of the right proportional valve RAO = 50.0.

[0117] Step 3: If it is in automatic mode and the enable signal EN is TRUE, the automatic cycle is executed, and in the automatic mode, each level of the sliding grate moves according to the unit speed reciprocating; the driving oil cylinder 2 first drives the sliding grate 1 to retreat to the retreat position, stays for 1-2s after retreating to the position, and then switches to forward movement; stays for 1-2s after advancing to the position, and then switches to retreat movement, and so on.

[0118] Among them, the sliding grate 1 position signal judgment: taking the maximum stroke LEN of the sliding grate 1 as an example,

[0119] Retreat to position: the left cylinder position feedback LFB < 3mm, and the right cylinder position feedback RFB < 3mm;

[0120] Advance to position: the left cylinder position feedback LFB > 257mm, and the right cylinder position feedback RFB > 257mm;

[0121] Among them, LEN: the maximum stroke of the sliding grate, and the above specific values can be adjusted according to the actual situation during debugging.

[0122] Step 4: If it is in automatic mode and the enable signal EN is FALSE, it is in standby state, and re-enters step 1 for mode selection.

[0123] When the automatic mode runs, the proportional valve 3 is controlled as:

[0124] Firstly, the calculation output value LOP of the left proportional valve and the calculation output value ROP of the right proportional valve are obtained by table lookup or linear mapping to obtain an initial value when the sliding grate 1 automatic mode runs and after each position reversal, and here, if the table lookup method is adopted, a corresponding relationship table needs to be set in advance; if the linear mapping method is adopted, a suitable coefficient needs to be obtained through linear fitting of experimental data in advance.

[0125] Then, during the sliding movement, the proportional valve 3 adopts incremental regulation, and the left and right proportional valves 3 calculate the left proportional valve regulation increment and the right proportional valve regulation increment according to the respective stroke deviation, and the formula is:

[0126] ;

[0127] ;

[0128] Wherein, TS=TM_CYCLE / 1000, XP, TI, TD are debugging setting values; the same set of XP, TI, TD setting values are adopted for the left and right proportional valves in the application, and two groups of different XP, TI, TD setting values can also be adopted in the actual debugging process;

[0129] TM_CYCLE: DCS scanning period; : left proportional valve adjustment increment; : right proportional valve adjustment increment; : left cylinder stroke deviation; : last cycle left cylinder stroke deviation; : last but one cycle left cylinder stroke deviation; : right cylinder stroke deviation; : last cycle right cylinder stroke deviation; : last but one cycle right cylinder stroke deviation; then, the adjustment increment calculated in the current cycle is used to update the calculation output value LOP of the left proportional valve and the calculation output value ROP of the right proportional valve in the last cycle, and the formula is:

[0130] Calculation output value LOP of the left proportional valve in the last cycle = calculation output value LOP of the left proportional valve in the current cycle + current cycle ;

[0131] Calculation output value ROP of the right proportional valve in the last cycle = calculation output value ROP of the right proportional valve in the current cycle + current cycle ;

[0132] When the calculation output value calculation result is less than 0, the value is 0; when the calculation output value calculation result is greater than 100, the value is 100.

[0133] Wherein, the AO output of the proportional valve 3 in the automatic mode:

[0134] When automatically advancing:

[0135] Left proportional valve AO output value LAO = 50.0 + LOP / 2.0;

[0136] Right proportional valve AO output value RAO = 50.0 + ROP / 2.0;

[0137] When automatically retreating:

[0138] Left proportional valve AO output value LAO = 50.0 - LOP / 2.0;

[0139] Right proportional valve AO output value RAO = 50.0 - ROP / 2.0;

[0140] When the manual mode switches to the automatic mode, the automatic mode initialization needs to be performed:

[0141] When the automatic mode starts to run, first, the starting position of the sliding grate 1 needs to be detected. If the starting position of the sliding grate 1 can not be at the position of the backward retreat, the sliding grate 1 needs to be first retreated to the position of the backward retreat.

[0142] Then, it is advanced again, so the system needs to record the initial position before the automatic mode starts to run in real time.

[0143] Among them, the initial position takes the larger one of the left oil cylinder position feedback LFB and the right oil cylinder position feedback RFB, and the difference between the initial position and the maximum stroke LEN of the sliding grate 1 is assigned to CYCLET_C, and the formula is: ;

[0144] Among them, CYCLET_C: expected stroke; LEN: maximum stroke of the sliding grate; LFB: position feedback of the left oil cylinder (mm); RFB: position feedback of the right oil cylinder (mm);

[0145] Finally, the system automatically adjusts the oil supply rate of the two proportional valves 3 to make the two oil cylinders 2 advance according to the expected stroke CYCLET_C.

[0146] The expected stroke calculation of the automatic mode is the basis of the control of the proportional valve 3, and it runs through the entire automatic mode movement process. When the automatic mode runs, the system automatically adjusts the oil supply rate of the two proportional valves 3 to make the two oil cylinders 2 advance according to the expected stroke CYCLET_C. Among them, the expected stroke CYCLET_C is the integral of the single-stage sliding grate 1 according to the unit speed SPEED in time, and the upper limit of the integral is the maximum stroke LEN of the sliding grate. CYCLET_C value is cleared after the sliding grate 1 switches to the backward direction after advancing to the position or switches to the forward direction after retreating to the position.

[0147] When the automatic mode runs, in order to realize the precise synchronous control of the left and right oil cylinders 2, ensure the smoothness, stability and reliability of the overall movement of the grate piece, so as to protect the stability and efficiency of the incineration process, and prevent mechanical damage caused by serious asynchronization, the oil cylinder 2 stroke deviation calculation needs to be performed:

[0148] When the automatic mode advances:

[0149] Left oil cylinder stroke deviation ;

[0150] Right oil cylinder stroke deviation ;

[0151] When the automatic mode retreats:

[0152] Left cylinder stroke deviation ;

[0153] Right cylinder stroke deviation ;

[0154] wherein, : left cylinder stroke deviation; : right cylinder stroke deviation; , is a percentage, and is the feedback of the deviation rate of the actual stroke and the expected stroke, and is the input signal of the incremental PID control module 6. The controller calculates the adjustment increment and required to make the deviation zero according to the values of and ; the value greater than zero indicates that the actual stroke of the cylinder lags behind; the value less than zero indicates that the actual stroke of the cylinder is ahead of schedule;

[0155] , : last cycle left and right cylinder stroke deviation;

[0156] , : last but one cycle left and right cylinder stroke deviation.

[0157] Therefore, the expected stroke calculation and the stroke deviation calculation formula are the basis for the control of the proportional valve 3, and are throughout the entire automatic mode movement process.

[0158] If the gap between the sliding grate piece and the side wall of the incinerator is small, and if the synchronization of the movement of the sliding grate piece is poor, and if the grate piece is deflected, it will cause the grate to jam and even mechanical damage. Therefore, when the sliding grate 1 moves, the stroke deviation of the left and right cylinders needs to be calculated in real time in the manual mode and the automatic mode, to ensure that it is within a reasonable range, and the formula is: ;

[0159] Taking =-20mm, =20mm, =-10mm, =10mm as an example, the specific values can be adjusted according to the actual situation during the debugging process:

[0160] Alarm triggering condition (set STA_ALM=TRUE): ≤-20mm , or ≥20mm ;

[0161] Alarm clearing condition (reset STA_ALM=FALSE): -10mm ≤ ≤10mm;

[0162] Where, LFB: left cylinder position feedback (mm); RFB: right cylinder position feedback (mm); : Alarm trigger lower limit value; : Alarm trigger upper limit value; : Alarm clearing lower limit value; : Alarm clearing upper limit value, STA_ALM: left and right cylinder stroke deviation alarm flag.

[0163] It can be seen from the above that the trigger condition and the clearing condition use different threshold values, and a hysteresis interval is used for stroke to prevent frequent switching of alarm state due to slight fluctuations near the boundary value, that is, to avoid jitter. Once the alarm is triggered, the deviation needs to be significantly reduced to clear it, which improves the stability of the system and reduces the mechanical stress caused by frequent alarms.

[0164] Therefore, the left and right cylinder deviation alarm is the basis for the control of the stop valve 4, and is throughout the entire movement process (manual mode and automatic mode), forming a safety interlock to maximize the prevention of hardware damage and effectively prevent mechanical failures such as cylinder 2 strain caused by serious asynchronization.

[0165] The stop valve 4 is simultaneously opened when any of the following conditions is met: left stop valve LSV and right stop valve RSV (LSV, RSV is TRUE):

[0166] (a) manual forward;

[0167] (b) manual reverse;

[0168] (c) automatic mode and enable signal EN is TRUE.

[0169] The stop valve 4 is simultaneously closed when any of the following conditions is met: left stop valve LSV and right stop valve RSV (LSV, RSV is FALSE):

[0170] (a) manual stop;

[0171] (b) automatic mode and enable signal EN is FALSE;

[0172] (c) left cylinder position feedback LFB signal bad point;

[0173] (d) right cylinder position feedback RFB signal bad point;

[0174] (e) hydraulic system pressure feedback value is too low or too high.

[0175] Meanwhile, the closing signal of the stop valve 4 has higher priority than the opening signal of the stop valve 4.

[0176] In addition, when the left and right cylinder stroke deviation alarm flag STA ALM is TRUE, the unilateral stop valve 4 is closed to help reduce the left and right cylinder stroke deviation and restore synchronization.

[0177] Specifically, the following four cases are included:

[0178] When the left and right cylinder stroke deviation alarm flag STA ALM is TRUE and the left cylinder 2 is located at the front (LFB>RFB) during the forward movement of the sliding grate 1, the left stop valve 4 is closed (LSV is set to FALSE);

[0179] When the left and right cylinder stroke deviation alarm flag STA ALM is TRUE and the right cylinder 2 is located at the front (LFB<RFB) during the forward movement of the sliding grate 1, the right stop valve 4 is closed (RSV is set to FALSE);

[0180] When the left and right cylinder stroke deviation alarm flag STA ALM is TRUE and the left cylinder 2 is located at the front (LFB<RFB) during the backward movement of the sliding grate 1, the left stop valve 4 is closed (LSV is set to FALSE);

[0181] When the left and right cylinder stroke deviation alarm flag STA ALM is TRUE and the right cylinder 2 is located at the front (LFB>RFB) during the backward movement of the sliding grate 1, the right stop valve 4 is closed (RSV is set to FALSE);

[0182] In addition, the unilateral stop valve closing signal is restored to the opening state when STA ALM becomes FALSE.

[0183] Here, when the left and right cylinder stroke deviation alarm occurs, the unilateral stop valve 4 is closed to further ensure the synchronization of the left and right cylinders 2 in operation by cooperating with the incremental PID adjustment of the proportional valve 3.

[0184] In addition, before step 1, manual mode debugging, automatic mode debugging and safety test are performed respectively, and specifically:

[0185] Manual mode debugging:

[0186] The forward / backward function of each stage of the grate is tested separately to verify the linearity of the response of the proportional valve 3 and the feedback of the displacement transducer 5. The correspondence between the MVAL set value and the actual speed is checked, and the mapping coefficient is adjusted to ensure accuracy.

[0187] Automatic mode debugging:

[0188] First, run empty, observe the movement of the grate trajectory and stay time whether meet the design requirements.

[0189] Step by step load fuel, according to the combustion effect fine tuning each level speed coefficient , make the bed material uniform.

[0190] Safety test:

[0191] Simulate the pressure of hydraulic system, check whether the stop valve can reliably cut off the oil circuit.

[0192] Simulate the displacement transmitter signal abnormal, check whether the stop valve can reliably cut off the oil circuit.

[0193] Through the above design, the system can realize the flexible switching of manual fine adjustment and automatic continuous operation, and meet the requirements of different working conditions.

[0194] With the above ideal embodiments according to the present application as inspiration, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and must be determined by the scope of the claims.

Claims

1. A method of control of a reciprocating mechanical grate furnace, comprising a reciprocating mechanical grate furnace, characterized in that: The reciprocating mechanical grate furnace comprises The incinerator is used for burning waste and generating heat. The grate is arranged along the length direction of the incinerator body and forms stepped combustion areas, comprising multiple levels of sliding grates (1) and multiple levels of fixed grates arranged alternately, and oil cylinders (2) are installed at both ends of the sliding grates (1) to synchronously drive the sliding grates (1) to reciprocate, a proportional valve (3) and a stop valve (4) are connected to each oil cylinder (2), and a displacement transmitter (5) is built in each oil cylinder (2). The incremental PID control module (6) is stored in the memory of the controller hardware platform in the form of a program and is executed by the processor in the controller hardware platform, is used for periodically calculating and outputting a control amount incremental signal according to the deviation of the feedback signal and the set value, the input end of the proportional valve (3) is connected to the output end of the incremental PID control module (6), the opening of the proportional valve (3) is adjusted through the control increment output by the incremental PID control module (6), and then the precise control of the controlled parameter is realized. The specific steps are as follows: Step 1: starting, entering the manual mode and the automatic mode selection, when running, corresponding control logic is executed according to the current mode, and the proportional valve (3) control signal is output; Step 2: if the manual mode is entered, a manual instruction is received, the sliding grate (1) is set according to the manual given opening MVAL set value, and the corresponding instruction is executed; Step 3: if the automatic mode is entered and the enable signal EN is TRUE, the automatic cycle is executed, the oil cylinder (2) first drives the sliding grate (1) to retreat to the retreat position, stays for 1-2 s after retreating to the retreat position, and then switches to the forward movement; after advancing to the position, staying for 1-2 s, the movement is switched to the retreat movement again; Step 4: if the automatic mode is entered and the enable signal EN is FALSE, the standby state is entered, and step 1 is re-entered for mode selection; When the control method runs in the automatic mode, the control of the proportional valve (3) comprises the following steps: Step a: initial value setting, when the sliding grate (1) starts to run in the automatic mode and every time the position is reversed, the initial values of the calculation output values LOP and ROP of the left proportional valve and the right proportional valve are determined through table lookup or linear mapping; Step b: incremental adjustment, during the sliding movement, the left and right proportional valves (3) are independently adjusted by the incremental PID control module (6), the left and right proportional valves (3) calculate the left proportional valve adjustment increment and the right proportional valve adjustment increment according to the respective stroke deviation , the formula is: ​ ； ； Wherein, TS=TM_CYCLE / 1000, XP, TI and TD are debugging setting values; TM_CYCLE: DCS scan cycle; : Left proportional valve adjustment increment : Right proportional valve adjustment increment : Left cylinder stroke deviation : Last cycle left cylinder stroke deviation : Last but one cycle left cylinder stroke deviation : Right cylinder stroke deviation : Last cycle right cylinder stroke deviation : Last but one cycle right cylinder stroke deviation Step c: output updating, the adjustment increment calculated in the current period is used to update the calculation output values LOP and ROP of the left proportional valve and the right proportional valve in the last period, and the formula is as follows: The calculation output value of the proportional valve in the current period = the calculation output value of the proportional valve in the last period + the adjustment increment in the current period.

2. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: The overall reciprocating speed of the grate is a reference speed The speed coefficient of each sliding grate (1) is , The value range of the speed coefficient is 0% to 100%, and the actual reciprocating unit speed of the single-stage sliding grate (1) is .

3. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: The movement control mode of the grate comprises a manual mode and an automatic mode.

4. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: When the manual mode is switched to the automatic mode, the automatic mode is initialized, and the specific steps are as follows: Step A: position detection and reset, the starting position of the sliding grate (1) is detected, if the starting position of the sliding grate (1) is not the retreat position, the sliding grate (1) is controlled to retreat to the retreat position and then advance. Step B: desired stroke calculation, obtain left side oil cylinder position feedback LFB and right side oil cylinder position feedback RFB; take the larger value of the two as the initial value; calculate the desired stroke: ; CYCLET_C: desired stroke; LEN: maximum stroke of the sliding grate; LFB: position feedback of the left cylinder (mm); RFB: position feedback of the right cylinder (mm); Step C: synchronous control is executed, and the oil supply rate of the two proportional valves (3) is automatically adjusted to drive the two side cylinders (2) to travel according to the desired stroke CYCLET_C.

5. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: When the automatic mode is running, the cylinder (2) stroke deviation calculation is as follows: When the automatic forward is running: left cylinder stroke deviation ; right cylinder stroke deviation ; When the automatic backward is running: left cylinder stroke deviation ; right cylinder stroke deviation ; wherein, : left side oil cylinder stroke deviation; : last cycle left side oil cylinder stroke deviation; is a percentage, and the feedback is the deviation rate of the actual stroke of the oil cylinder from the expected stroke; when the value is greater than zero, it indicates that the actual stroke of the oil cylinder lags behind; when the value is less than zero, it indicates that the actual stroke of the oil cylinder leads;​ , : left and right cylinder stroke deviation of last cycle , : Left and right cylinder stroke deviation of last cycle 6. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: The sliding grate (1) is in place in step 3, and the signal is determined as follows: Retreat to position, left cylinder position feedback , and right cylinder position feedback ; In position, left cylinder position feedback , and right cylinder position feedback ; wherein LEN: maximum stroke of the sliding grate, is a set retreat-to-position tolerance threshold, is a set approach-to-position tolerance threshold.

7. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: The analog output AO control of the proportional valve (3) in the automatic mode is as follows: When the automatic forward is running: The left proportional valve output value LAO=50.0+LOP / 2.0; The right proportional valve output value RAO=50.0+ROP / 2.0; When the automatic backward is running: The left proportional valve output value LAO=50.0-LOP / 2.0; The right proportional valve output value RAO=50.0-ROP / 2.

0.

8. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: The analog output AO control of the proportional valve (3) in the manual mode is as follows: When the manual forward is running: The left proportional valve output value LAO=50.0+CMD_MVAL / 2.0; The right proportional valve output value RAO=50.0+CMD_MVAL / 2.0; When the manual backward is running: The left proportional valve output value LAO=50.0-CMD_MVAL / 2.0; The right proportional valve output value RAO=50.0-CMD_MVAL / 2.0; When the manual stop is running: The left proportional valve output value LAO=50.0; The right proportional valve output value RAO=50.0; Wherein, 50.0: corresponding proportional valve mid-reference value; CMD_MVAL: manual speed command value.

9. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: In the manual mode and the automatic mode, the stroke deviation of the left and right oil cylinders is calculated in real time when the sliding grate (1) moves , formula: ; Alarm trigger condition: or ; Alarm clearing condition: ; Wherein, LFB: left cylinder position feedback (mm); RFB: right cylinder position feedback (mm); : alarm trigger lower limit value; : alarm trigger upper limit value; : alarm clear lower limit value; : alarm clear upper limit value.

10. A method of controlling a reciprocating mechanical grate furnace according to claim 1, characterized in that: The stop valve (4) satisfies any one of the following conditions: manual forward, manual backward, or automatic mode and enable signal EN is TRUE, and simultaneously opens the left stop valve LSV and the right stop valve RSV; The stop valve (4) satisfies any one of the following conditions: manual stop, automatic mode and enable signal EN is FALSE, left cylinder position feedback LFB signal bad point, right cylinder position feedback RFB signal bad point, or hydraulic system pressure feedback value is too low or too high, and simultaneously closes the left stop valve LSV and the right stop valve RSV; When the left and right cylinder stroke deviation alarm flag is triggered, according to the size relationship between the left cylinder position feedback value LFB and the right cylinder position feedback value RFB, the single-sided stop valve (4) is closed; And, the closing signal of the stop valve (4) has higher priority than the opening signal of the stop valve (4).

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