A sludge drying incineration system control method

Abstract

The application provides a sludge drying and incineration system control method, which comprises the following steps: according to the preset steam flow FU required by the incineration system, the sludge material quantity required by the sludge feeding quantity FM is calculated based on the heat relationship; then, in the process of sludge drying and incineration in the incinerator, the steam flow FN_U output by the incinerator is monitored in real time; the preset steam flow FN and the real-time steam flow FN_U generated by incineration are compared; the rotation speed SV of the screw equipment for feeding the incinerator and the secondary air flow are adjusted; and the size of the real-time steam flow FN_U generated by the current incineration is controlled by controlling the material quantity in the incinerator and the secondary air flow, so that the size of the real-time steam flow FN_U generated by the current incineration is consistent with the preset steam flow FN. The method can meet the demand of automatic control on the basis of ensuring safe production, and greatly reduces the amount of manual participation in the control process.

Description

Technical Field

[0001] This invention relates to the field of waste resource utilization technology, specifically a control method for a sludge drying and incineration system. Background Technology

[0002] With increasingly stringent environmental protection requirements, sludge generated in urban life, such as sewage sludge, water supply sludge, drainage pipe sludge, dredging sludge, and construction mud, all require harmless treatment. The typical process involves: first, dewatering the sludge; then, feeding it into drying equipment, such as mechanical dewatering equipment, for preliminary drying; then, feeding it into an incineration system for incineration and drying; and finally, burying or otherwise harmlessly treating the incineration residue. In existing technologies, sludge drying and incineration systems typically employ a buffer hopper for sludge feeding, using high and low material levels, weighing modules, and the start and stop of the feed / discharge cycles for intermittent metering. For example, an underground dry sludge storage and feeding system disclosed in application number CN202122522051.9 uses this method for feeding; however, this method has poor metering accuracy and significantly negatively impacts the continuous and stable operation of the incinerator. Meanwhile, in order to achieve automated control of sludge drying and incineration systems, some technicians use sensors to monitor parameters such as furnace temperature or bed thickness to achieve interlocking control of feeding equipment and incineration control. However, most existing incineration system control methods only perform interlocking control of single parameters such as furnace temperature or bed thickness. The accuracy of the interlocking control results is insufficient, and the whole process still requires a high degree of human intervention. Summary of the Invention

[0003] To address the issues of poor feeding accuracy and combustion control precision in existing sludge drying and incineration systems, and the need for significant manual intervention in combustion control, this invention provides a control method for a sludge drying and incineration system. This method enables joint control of the feeding and incineration processes, ensuring the accuracy of both processes and significantly reducing the amount of manual intervention required in the control process.

[0004] The technical solution of the present invention is as follows: a control method for a sludge drying and incineration system, characterized in that it includes the following steps:

[0005] S1: Based on the type of sludge material to be incinerated and dried, determine the working thickness TH of the sludge layer, the working furnace temperature TEM, and the steam flow rate FN output within the metering unit T that the sludge drying and incineration system needs to maintain for safe operation.

[0006] S2: Calculate the heat QR required for combustion in the incinerator based on the preset steam flow rate FN within the metering unit T.

[0007] FN = QR / H;

[0008] Where QR is the calorie unit MJ / H corresponding to the preset steam flow rate FN, and H is the enthalpy unit of steam MJ / KG;

[0009] S3: Calculate the single feed rate FM of the incinerator based on the heat required for combustion QR;

[0010] QR = (Wr + C * Fa)φ;

[0011] Wherein, the sludge combustion heat Wr is the combustion heat value corresponding to the sludge feed amount FM; φ is the boiler thermal efficiency; and C is the air enthalpy.

[0012] The heat of combustion of air, Fa, is the calorific value that can be provided by the combustion of air at a flow rate of FDFSTN.

[0013] FDFSTN=RAMDA×(CDFFST1×LHVSMS+CDFFST2)×RESSTN;

[0014] Wherein, FDFSTN is the air flow rate required for the sludge feed FM to burn in the furnace, RAMDA is the excess air ratio, LHVSMS is the calorific value of the sludge material, RESTN is the material input of the sludge material, and the initial value of RESTN is the initial single feed amount FM of the feeding system; CDFFST1 is the theoretical air conversion coefficient required for the combustion of heat-releasing substances in the sludge; CDFFST2 is the theoretical air conversion coefficient parameter required for the oxidation of non-heat-releasing substances in the sludge.

[0015] S4: Based on FM, calculate the rotational speed SV of the screw conveyor used for feeding the incinerator in the sludge drying and incineration system within the unit of measurement T;

[0016] SV = FM / (n*T)

[0017] Where FM is the amount of sludge feed that needs to be supplied to the incinerator per unit time T; n is the relationship parameter between the rotation speed and the conveying capacity of the screw conveyor used for feeding the incinerator, which is the inherent coefficient of the screw conveyor; and T is the single metering time.

[0018] S5: Calculate the primary air flow rate and secondary air flow rate required for combustion in the sludge drying and incineration system;

[0019] Primary airflow = Secondary airflow = FDFSTN * 50%;

[0020] S6: After starting the incinerator, supply air to the incinerator according to the primary air flow rate and the secondary air flow rate, and at the same time control the screw conveyor for feeding the incinerator to feed the incinerator at a speed SV.

[0021] S7: During the combustion process, by measuring the differential pressure at both ends of the material layer on the incinerator and the input air flow rate of the combustion furnace, calculate the material layer thickness PAT and the generated steam flow rate FN_U;

[0022] Current value of combustion mode Material thickness value PAT:

[0023] PAT = CPAT1 × (PHE_U - PIN - PNOFF)

[0024] Where, PHE_U is the pressure under the furnace bed, PIN is the pressure inside the furnace, PNOFF is the pressure loss, and CPAT1 is the conversion coefficient parameter between the furnace bed differential pressure and the bed material height;

[0025] Real-time steam flow rate FN_U generated by incineration:

[0026]

[0027] Where, DLA_U is the steam pipe diameter at the maximum steam flow rate, DLA_L is the steam pipe diameter at the minimum steam flow rate, ZN_U is the opening degree of the steam pressure regulating valve at the maximum steam flow rate, ZN_L is the opening degree of the steam pressure regulating valve at the minimum steam flow rate; PSH is the steam pressure before the valve, PN U is the valve pressure loss, PN_U is the steam drum steam pressure at the maximum steam flow rate, PN_L is the steam drum steam pressure at the minimum steam flow rate, FDF is the steam working condition flow rate, ACL7_U is the steam drum steam pressure correction coefficient, ACL8_U is the pre-valve pressure correction coefficient, and APP_FDOFF is the steam flow deviation;

[0028] S8: Judge the relationship between the preset output steam flow rate FN within the measurement unit T and the currently generated steam flow rate FN_U by incineration;

[0029] If FN > FN_U, it means that the currently generated steam flow rate has not reached the preset value, and execute step S9;

[0030] If FN < FN_U, it means that the currently generated steam flow rate exceeds the preset steam supply value of the incinerator, and execute step S10;

[0031] If FN_U = FN, it means that the currently generated steam flow rate meets the preset value, and execute step S13;

[0032] S9: Simultaneously perform the following improvement operations to increase the steam flow rate FN output by the incinerator within the measurement unit T, and then execute step S11;

[0033] Improvement operation 1: Adjust the rotation speed SV of the screw device for feeding the incinerator to make it larger;

[0034] Improvement operation 2: Adjust the secondary air flow rate to make it larger;

[0035] S10: Simultaneously perform the following reduction operations to reduce the steam flow rate FN output by the incinerator within the measurement unit T, and then perform step S11;

[0036] Reduction operation 1: Adjust the rotational speed SV of the spiral device for feeding the incinerator to make it smaller;

[0037] Reduction operation 2: Adjust the secondary air flow rate to make it smaller;

[0038] S11: Judge the relationship between the current value of the material thickness PAT and the preset working thickness TH of the sludge layer;

[0039] If PAT < TH, adjust the rotational speed SV of the spiral device for feeding the incinerator to make it larger, and then perform step S12;

[0040] If PAT > TH, adjust the rotational speed SV of the spiral device for feeding the incinerator to make it smaller, and then perform step S12;

[0041] If PAT = TH, perform step S12;

[0042] S12: Monitor and adjust the flue gas temperature and flue gas residence time in the incinerator in real time to inhibit the generation of dioxins in the flue gas;

[0043] S13: Loop and execute steps S7 - S12, continuously monitor the status of the incinerator, and achieve dynamic control of the incinerator status;

[0044] S14: Feed the incinerator from the buffer bin based on the spiral device for feeding the incinerator; The buffer bin is provided with a high material level and a low material level;

[0045] While executing steps S2 - S13, simultaneously monitor the material height of the buffer bin in real time. When the material in the buffer bin reaches the high material level, stop feeding the buffer bin. When the material in the buffer bin reaches the low material level, feed the buffer bin;

[0046] The calculation method of the single - feeding amount FM for each feeding to the buffer bin is as follows:

[0047] FM = CMHH - CML + n * SV * T

[0048] Where, CMHH is the total weight of the material in the buffer bin when the material is at the high material level; CML is the total weight of the material in the bin when the material is at the low material level; n is the relationship parameter between the rotational speed and the conveying capacity of the spiral device for feeding the incinerator; SV is the rotational speed of the spiral device for feeding the incinerator; T is the single - measurement time.

[0049] It is further characterized in that:

[0050] Before step S8 is executed, the following steps are performed to confirm the relationship between the target value and the preset value of the output steam pressure:

[0051] a1: Calculate the steam pressure FNP corresponding to the preset steam flow FN and the steam pressure FN_UP corresponding to the steam flow FN_U under the front furnace bed;

[0052] a2: Compare the relationship between FNP and FN_UP;

[0053] If FNP and FN_UP are equal, execute step S8;

[0054] Otherwise, calculate the steam flow deviation FNCDEV:

[0055] FNCDEV = (FNCNOW - FNCSTN) / FNCSTN

[0056] Where, FNCDEV is the steam flow deviation; FNCNOW is the current value of the steam flow regulating valve; FNCSTN is the steam flow reference value, and its value is the value corresponding to the output steam flow FN within the measurement unit T;

[0057] a3: Adjust the steam flow regulating valve of the output steam of the incineration system:

[0058] If FNP > FN_UP, within the range of [GNCCTL_MIN, GNCCTL_MAX], according to the preset steam pressure regulating valve opening control table, turn down the steam flow regulating valve and execute step a4;

[0059] If FNP < FN_UP, within the range of [GNCCTL_MIN, GNCCTL_MAX], according to the preset steam pressure regulating valve opening control table, turn up the steam flow regulating valve and execute step a4;

[0060] The steam pressure regulating valve opening control table stipulates the corresponding steam pressure regulating valve opening control value GNCCTL when the steam flow deviation FNCDEV takes different values;

[0061] a4: Loop and execute steps a1 to a3;

[0062] If GNCCTL exceeds the range of [GNCCTL_MIN, GNCCTL_MAX] and FNP and FN_UP are still not equal, directly execute step S8;

[0063] Where, GNCCTL_MIN and GNCCTL_MAX are respectively the minimum and maximum opening values allowed for adjustment of the steam flow regulating valve in this system;

[0064] The method for adjusting the rotational speed SV of the screw conveyor for feeding the incinerator includes:

[0065] b1: Calculate the feed screw speed baseline value VSSTN:

[0066] VSSTN=SMSVS×VSAVE+(1-SMSVS)×VSSTN 前

[0067] Where VSSTN is the reference value of the feed screw speed, SMSVS is the smoothing coefficient of the feed screw speed, VSAVE is the average value of the feed screw speed, and VSSTN is the average value of the feed screw speed. 前 The feed screw speed is the reference value before return;

[0068] b2: Calculate the combustion chamber temperature deviation TMCDEV:

[0069] TMCDEV = TMCNOW - TMCSTN

[0070] b3: Based on the temperature-rate correction table, determine the feed screw speed and combustion chamber temperature correction coefficient MVST.

[0071] The temperature-rate correction correspondence table records the values ​​of MVST when TMCDEV falls within different ranges.

[0072] When TMCDEV∈(-∞,-60), MVST=0.2;

[0073] When TMCDEV∈[-60,-20), MVST=-0.005×TMCDEV-0.1;

[0074] When TMCDEV∈[-20,20], MVST=0;

[0075] When TMCDEV∈(20,45], MVST=-0.008×TMCDEV+0.16;

[0076] When TMCDEV∈(45,∞), MVST=-0.2;

[0077] b4: Calculate the feed screw speed control value:

[0078] VSCTL=(1+MVST)×VSSTN

[0079] Wherein, VSMIN≤VSCTL≤VSMAX, VSCTL is the feed screw speed control value, MVST is the feed screw speed combustion chamber temperature correction coefficient, VSMIN is the preset minimum feed screw speed, and VSMAX is the preset maximum feed screw speed;

[0080] b5: Each time the rotational speed SV of the screw conveyor used for feeding the incinerator is adjusted, the value of the adjustment is VSCTL;

[0081] When adjusting the secondary air flow rate, the opening of the secondary air damper must be adjusted simultaneously. The specific method for adjusting the opening of the secondary air damper includes the following steps:

[0082] c1: Calculate the reference value for the opening of the secondary air damper;

[0083] The secondary air damper opening reference values ​​include: the maximum opening reference value ZNUSTN for large air volume and the minimum opening reference value ZNLSTN for small air volume;

[0084] The calculation method is as follows:

[0085] When LHVSMS∈(0,2), ZNUSTN=60, ZNLSTN=20;

[0086] When LHVSMS∈[2,7], ZNUSTN=2×LHVSMS+56, ZNLSTN=3×LHVSMS+14;

[0087] When LHVSMS∈(7,∞), ZNUSTN=70; ZNLSTN=35;

[0088] LHVSMS is the calorific value of sludge material.

[0089] c2: Calculate the baffle opening correction value MZNPAT when the air volume is large;

[0090] When PATDEV∈(-∞,-20), MZNPAT=-6;

[0091] When PATDEV∈[-20,-6), MZNPAT=.5×PATDEV+3;

[0092] When PATDEV∈[-6,6], MZNPAT=0;

[0093] When PATDEV∈(6,20], MZNPAT=0.5×PATDEV-3;

[0094] When PATDEV∈(20,∞), MZNPAT=6;

[0095] PATDEV represents the combustion mode deviation.

[0096] PATDEV = PAT - MPATCTL;

[0097] Where PAT is the current value of the combustion mode, and MPATCTL is the reference value of the combustion mode.

[0098] c3: ZNUCTL, the control value for the opening of the secondary air damper when calculating large air volume;

[0099] ZNUCTL=ZNUSTN+MZNPAT

[0100] Wherein, ZNUSTN is the maximum reference value of the opening when the air volume is large; MZNPAT is the correction value for the damper opening when the air volume is large.

[0101] c4: Calculate the baffle opening correction value MZNTMC when the air volume is small;

[0102] When TMCDEV∈[-∞,20], MZNTMC=0;

[0103] When TMCDEV∈(20,50], MZNTMC=0.125×TMCDEV+2.5;

[0104] When TMCDEV∈(50,∞), MZNTMC=5;

[0105] Wherein, TMCDEV is the combustion chamber temperature deviation, calculated as follows:

[0106] TMCDEV = TMCNOW - TMCSTN;

[0107] Where TMCNOW is the current combustion chamber temperature and TMCSTN is the reference combustion chamber temperature;

[0108] c5: Calculate the secondary air damper opening control value ZNLCTL when the air volume is small;

[0109] ZNLCTL=ZNLSTN+MZNTMC

[0110] Wherein, ZNLSTN is the minimum reference value of the opening when the air volume is small, and MZNTMC is the correction value of the damper opening when the air volume is small;

[0111] c6: Construct a coordinate system with the horizontal axis representing air volume and the vertical axis representing the opening value; place the secondary air damper opening control value ZNLCTL for small air volume and the secondary air damper opening control value ZNUCTL for large air volume into the coordinate system, and draw a straight line passing through the two points, denoted as: opening control line;

[0112] c7: Obtain the secondary air flow rate that needs to be injected. On the opening control line, on the line segment between ZNLCTL and ZNUCTL, find the point that satisfies the secondary air flow rate and use it as the adjusted secondary air damper opening.

[0113] In step S12, the flue gas temperature and residence time in the incinerator are monitored and adjusted in real time to suppress the formation of dioxins in the flue gas. This specifically includes the following steps:

[0114] d1: Install a temperature sensor at the flue gas outlet of the incinerator to monitor the flue gas outlet temperature (Texit) in real time;

[0115] d2: Calculate the residence time (TR) of the flue gas in the incinerator at the current moment.

[0116]

[0117] Where V is the volume of the dilute phase zone of the incinerator, which serves as the secondary combustion chamber for flue gas; FN_U is the current steam flow rate output by the incineration system; N is the conversion coefficient between steam flow rate and flue gas flow rate under standard conditions; and Texit is the real-time flue gas temperature at the incinerator outlet.

[0118] d3: Compare TR and dioxin inhibition time thresholds;

[0119] When TR ≤ the dioxin inhibition time threshold, reduce the amount of FN_U until TR > the dioxin inhibition time threshold and then stop.

[0120] Otherwise, repeat steps d2 to d3.

[0121] d4: Real-time monitoring of flue gas temperature Tsec in the secondary combustion chamber;

[0122] When Tsec meets any of the following conditions, the auxiliary burner is activated and step d5 is executed;

[0123] Auxiliary burner activation condition 1: Tsec < 855℃

[0124] Auxiliary burner activation condition 2: Tsec < 860℃ for 5 consecutive minutes;

[0125] d5: After the auxiliary burner is turned on, after Tsec rises above 900°C, confirm whether Tsec meets the following conditions;

[0126] Auxiliary burner shutdown condition: Tsec > 880℃ for 5 consecutive minutes;

[0127] If the conditions are met, then the auxiliary burner is turned off;

[0128] Otherwise, keep the auxiliary burner retracted until the auxiliary burner shut-off condition is met;

[0129] d6: Repeat steps d2 to d4 to ensure that the flue gas temperature and residence time in the incinerator meet the conditions for suppressing the generation of dioxins in the flue gas.

[0130] It also includes the following steps:

[0131] S15: When performing steps S2 - S14, continuously monitor and adjust the oxygen concentration in the incinerator to ensure that the combustion in the incinerator meets the conditions for complete combustion, specifically including the following steps

[0132] d1: Set the target oxygen content concentration range [SOmin, SOmax] of the flue gas in the incinerator according to the type of sludge material dried and incinerated this time, where SOmin is the minimum value of the oxygen content concentration in the flue gas and SOmax is the maximum value of the oxygen content concentration in the flue gas;

[0133] d2: Install an oxygen content analyzer for testing the oxygen concentration in the flue gas at the flue gas outlet of the incinerator, and continuously monitor the oxygen content St in the flue gas output by the incinerator;

[0134] d3: Confirm the relationship between St and the target oxygen content concentration;

[0135] When St < SOmin, adjust the secondary air flow rate to increase it, and at the same time adjust the opening degree of the secondary air baffle;

[0136] When St > SOmax, adjust the secondary air flow rate to decrease it, and at the same time adjust the opening degree of the secondary air baffle;

[0137] Otherwise, loop and execute steps d2 - d3;

[0138] When feeding the buffer bin for the first time and starting the feeding screw equipment, it is necessary to calibrate the feeding screw equipment;

[0139] The calibration method for the feeding amount per unit time of the feeding screw equipment includes the following steps:

[0140] e1: Install a feeding screw equipment and a scraper conveyor between the dry mud bin storing the material and the buffer bin,

[0141] Based on the feeding screw equipment for transporting to the buffer bin, and based on the scraper conveyor, send the sludge on the feeding screw equipment into the buffer bin;

[0142] e2: Set the frequency of the feeding screw equipment to: SupN;

[0143] Run the feeding screw equipment and the scraper conveyor simultaneously;

[0144] e3: Feed the buffer bin based on the frequency SupN until the material level in the buffer bin reaches the high material level, then record the running time of the feeding screw as: SupT1, and measure the total amount of material in the buffer bin at this time as: SupW1;

[0145] e5: Stop the feeding screw;

[0146] e6: Continuously confirm the change in the total weight of the material in the buffer bin until the total weight of the material in the buffer bin stops changing, and record the total amount of material at this time as: SupW2;

[0147] e7: Calculate the feed rate SupQ per unit time of the feeding screw conveyor when the frequency is SupN; and the sludge storage weight SccW of the scraper conveyor.

[0148] SupQ = SupW2 / SupT1;

[0149] SccW≈SupW2-SupW1.

[0150] This application provides a control method for a sludge drying and incineration system. Based on the preset required steam flow rate FU of the incineration system and the heat relationship, the method calculates the amount of sludge material required for combustion, including the sludge feed rate FM. Then, during the sludge drying and incineration process in the incinerator, the method monitors the output steam flow rate FN_U of the incinerator in real time, compares the preset output steam flow rate FN with the real-time steam flow rate FN_U generated during incineration, and adjusts the rotational speed SV and secondary air flow rate of the screw conveyor used for feeding the incinerator. By controlling the amount of material in the incinerator and the secondary air flow rate, the method controls the magnitude of the current real-time steam flow rate FN_U generated during incineration to maintain consistency with the preset output steam flow rate FN. Simultaneously, the method monitors the current incinerator temperature temp and the preset operating furnace temperature TEM. The method dynamically adjusts the secondary airflow based on the relationship between the current material thickness value PAT and the preset working thickness TH of the sludge layer, and adjusts the rotation speed SV of the screw conveyor for feeding the incinerator to ensure safe operation of the incinerator. Based on the dynamically adjusted SV, the feed rate of the buffer silo is dynamically adjusted to ensure that the feed rate of the buffer silo meets the feed requirements of the incinerator, ensuring the accuracy of the feed and incineration process control. This achieves fully automatic control of the incinerator's airflow, as well as automatic control of the start-up and shutdown of the screw conveyor and the speed of the incinerator feed screw. This method achieves the requirements of automated control while ensuring safe production, and greatly reduces the amount of manual intervention in the control process. Attached Figure Description

[0151] Figure 1 A schematic diagram of an embodiment of a sludge drying and incineration system;

[0152] Figure 2 A schematic diagram of a buffer silo for sludge feeding embodiment;

[0153] Figure 3 This is a process control diagram for the sludge drying and incineration system control method. Detailed Implementation

[0154] like Figure 1 The image shows an embodiment of a sludge incineration system using this method for fully automated control. It includes a bubbling fluidized bed incinerator 1, which stores and feeds materials based on a sludge feeding system 5. The bubbling fluidized bed incinerator 1 is equipped with a sludge inlet 2, a primary air inlet 3, a secondary air inlet 4, an auxiliary burner 6, and an ignition burner 7. The inner cavity of the bubbling fluidized bed incinerator 1, located above the secondary air inlet 4, is a secondary combustion chamber 9. A denitrification reaction zone is located within the secondary combustion chamber 9. A flue gas outlet 8 is located at the very top of the bubbling fluidized bed incinerator 1. In this embodiment, there are eight secondary air inlets 4, each equipped with an electronic control device to control the opening of the secondary air damper. The flue gas outlet 8 connects to a waste heat boiler 13, which is equipped with a steam drum 14 for storing the steam output from the system.

[0155] To achieve automated control of the system, pressure detection devices 12 are installed at various points within the incinerator to measure gas pressure in real time, according to control measurement requirements. Pressure detection devices 12 are also installed at various points within the steam drum 14 to monitor the steam pressure output from the waste heat boiler 13 in real time, according to the measurement requirements of the control method. Steam pressure regulating valves 16 are installed on the steam pipelines to regulate the steam pressure and flow rate output from the steam drum. Gas flow meters 15 are installed on gas pipelines such as the secondary air supply pipeline, primary air supply pipeline, and flue gas outlet 8 to monitor the volume of combustion air input to the incinerator and the volume of flue gas generated by the system in real time. An oxygen analyzer 10 for testing the oxygen concentration in the flue gas and a flue gas temperature sensor 11 for testing the flue gas temperature are installed at the flue gas outlet 8. In practical applications, the various devices are interconnected based on the PLC protocol to achieve data communication, and the overall automated control of the system is realized through the PLC controller.

[0156] like Figure 2 As shown, the sludge feeding system 5 includes a buffer silo 5-1 equipped with a weighing sensor 5-6, and a feeding screw conveyor 5-4 and a scraper conveyor 5-5 are set between the dry sludge silo 5-3 and the buffer silo 5-1. The buffer silo 5-1 feeds the sludge from the sludge inlet 2 into the bubbling fluidized bed incinerator 1 through the incinerator feeding screw conveyor 5-2.

[0157] The buffer silo 5-1 is equipped with a weighing module based on a weighing sensor 5-6, as well as high and low material levels (not marked in the figure). When the material in the buffer silo 5-1 reaches the bottom level, the material is conveyed from the dry mud silo 5-3 to the scraper conveyor 5-5 via a feeding screw conveyor 5-4. The scraper conveyor 5-5 lifts the material to the feed inlet of the buffer silo 5-1 to replenish it. When the material in the buffer silo 5-1 reaches the high level, the feeding screw conveyor 5-4 stops feeding the buffer silo 5-1. Based on the weighing module, the high and low material levels, and the precise measurement of the transmission parameters of the feeding screw conveyor 5-4 and the scraper conveyor 5-5, the feeding of the buffer silo 5-1 to the incinerator can be precisely and automatically controlled.

[0158] To ensure the accuracy of material conveying measurement, when replenishing the buffer silo, the feeding screw device 5-4 needs to be calibrated upon initial startup to determine the ratio between the material accumulation in the scraper conveyor and the frequency of the feeding screw device to the material conveying volume.

[0159] The calibration method for the unit time feeding amount of a screw conveyor for feeding includes the following steps:

[0160] e1: Install a feeding screw conveyor and scraper conveyor between the dry mud silo and the buffer silo for storing materials.

[0161] The feed screw conveyor transports sludge from the feed screw conveyor into the buffer silo, and the scraper conveyor delivers sludge from the feed screw conveyor into the buffer silo.

[0162] e2: Set the frequency of the feeding screw device to: SupN;

[0163] Simultaneously operate the screw conveyor and scraper conveyor for feeding;

[0164] e3: Based on the frequency SupN, the buffer hopper is replenished until the material level in the buffer hopper reaches the high level. The running time of the replenishing screw is recorded as SupT1, and the total amount of material in the buffer hopper at this time is measured as SupW1.

[0165] e5: Stop feeding screw;

[0166] e6: Continuously monitor the change in the total weight of the material in the buffer bin until the total weight of the material in the buffer bin stops changing, and record the total amount of material at this time as: SupW2;

[0167] e7: Calculate the feed rate SupQ per unit time of the screw conveyor when the frequency is SupN; and the sludge weight SccW of the scraper conveyor.

[0168] SupQ = SupW2 / SupT1;

[0169] SccW≈SupW2-SupW1.

[0170] The relationship between the rotational speed and frequency of a screw conveyor is as follows:

[0171] Rotational speed = (60 * frequency * 60) / (2 * π * screw pitch of the screw conveyor)

[0172] Here, frequency refers to the power supply frequency, which can be adjusted according to actual needs; the screw pitch of the screw conveyor refers to the distance a point on the helix moves forward with each revolution of the screw conveyor; and the speed of the screw conveyor refers to the number of revolutions per minute, usually expressed in revolutions per minute (RPM).

[0173] Based on the weighing module, high and low material level settings, and with the precise measurement of 5-4 parameters of the feeding screw device, the feeding of the dry mud bin to the flushing bin can be accurately and automatically achieved.

[0174] like Figure 3 As shown, this application includes a control method for a sludge drying and incineration system, which includes the following steps.

[0175] S1: Based on the type of sludge material to be incinerated and dried, determine the working sludge layer thickness TH, working furnace temperature TEM, and steam flow rate FN per unit T required for safe operation of the sludge drying and incineration system. The specific values ​​of TH, TEM, and FN are set before starting the incinerator, depending on the type of incinerator and the composition of the material.

[0176] In this embodiment, the sludge drying and incineration system uses the high-heat flue gas generated by the bubbling fluidized bed incinerator 1 to output steam from the waste heat boiler 13 as the output of the sludge drying and incineration system. The design objective of the sludge drying and incineration system is to maintain the total steam flow rate of the boiler at a given set value. Therefore, in this method, the stable input of sludge into the incinerator is achieved by controlling the feeding screw conveyor 5-4 and the incinerator feeding screw conveyor 5-2. This method controls the material residence time by controlling the material layer thickness; adjusts the primary and secondary air to provide sufficient oxygen for full oxidation of the material and improves the stirring intensity; controls the incinerator temperature to ensure the temperature required for material combustion; and reduces the sludge loss on ignition in the incinerator by controlling the material layer thickness, primary air volume, and secondary air volume, thereby reducing the mechanical unburned loss of sludge combustion, improving the thermal efficiency of combustion, reducing the amount of sludge residue, and improving the volume reduction after sludge incineration. By controlling the conditions for dioxin generation, the emission of pollutants in the flue gas is reduced; and by controlling the secondary air volume, the stability of the incinerator temperature is ensured.

[0177] S2: Calculate the heat required for combustion QR based on the preset steam flow rate FN within the metering unit T;

[0178] FN = QR / H;

[0179] Where QR is the calorie unit MJ / H corresponding to the preset steam flow rate FN, and H is the enthalpy unit of steam MJ / KG.

[0180] S3: Calculate the single feed amount FM based on the heat required QR for FN;

[0181] The heat of combustion of sludge in the furnace, Wr, and the heat of combustion of air, Fa;

[0182] QR = (Wr + C * Fa)φ;

[0183] Wherein, the sludge combustion heat Wr is the combustion heat value corresponding to the sludge feed amount FM; φ is the boiler thermal efficiency, which is the boiler's factory setting value; and C is the air enthalpy, which is a fixed value.

[0184] The heat of combustion of air, Fa, is the calorific value that can be provided by the combustion of air at a flow rate of FDFSTN.

[0185] FDFSTN=RAMDA×(CDFFST1×LHVSMS+CDFFST2)×RESSTN;

[0186] Wherein, FDFSTN is the air flow rate required for combustion of sludge feed FM in the furnace; RAMDA is the excess air ratio, a parameter of the incinerator, with different values ​​depending on the furnace type; LHVSMS is the calorific value of the sludge material. In practical applications, the material composition is tested before each incineration control plan is planned to obtain the corresponding calorific value of the material; RESTN is the amount of sludge material fed into the furnace. The initial value of RESTN is the initial single feed amount FM of the feeding system; CDFFST1 is the theoretical air conversion coefficient required for combustion of heat-releasing substances in the sludge; CDFFST2 is the theoretical air conversion coefficient required for oxidation of non-heat-releasing substances in the sludge. CDFFST1 and CDFFST2 are obtained by measuring the material composition before the incineration plan is planned.

[0187] S4: Based on FM, calculate the rotational speed SV of the screw conveyor used for feeding the incinerator in the sludge drying and incineration system within the unit of measurement T;

[0188] SV = FM / (n*T)

[0189] Where FM is the amount of sludge feed that needs to be supplied to the incinerator per unit time; n is the relationship parameter between the rotation speed of the screw conveyor used for feeding the incinerator and the conveying capacity, with an inherent coefficient; and T is the single metering time.

[0190] S5: Calculate the primary and secondary air flow rates required for combustion and combustion support in the sludge drying and incineration system; during initial air supply, the primary and secondary air flow rates are supplied to the incinerator at the same flow rate.

[0191] Primary airflow = Secondary airflow = FDFSTN * 50%.

[0192] S6: After starting the incinerator, supply air to the incinerator according to the primary air flow rate and the secondary air flow rate, and at the same time control the screw conveyor for feeding the incinerator to feed the material to the incinerator at a speed of SV.

[0193] Before starting the incinerator, the required heat (QR) for combustion is calculated based on data such as the density and calorific value of the sludge used as incineration material, and the preset steam flow rate (FN) required by the incineration system. Then, the required amount of material to be fed in and the required air volume for combustion are derived. Taking heat loss into account, the feed rate of the screw conveyor for incinerator feeding and the fan frequency required for automatic system control are calculated. These data, calculated based on theoretical data, are used as the initial data for starting the incinerator and feeding system.

[0194] S7: During combustion, in order to ensure production safety and control the loss on ignition, it is necessary to control the thickness of the material layer in the furnace.

[0195] The pressure detection device 12 installed inside the furnace measures the differential pressure at both ends of the incinerator material layer and the air flow rate input to the combustion furnace is detected by the gas flow meter 15. The material layer thickness PAT and the generated steam flow rate FN_U at the current moment are calculated.

[0196] Current material thickness value (PAT) for combustion mode:

[0197] PAT=CPAT(1)×(PHE_U-PIN-PNOFF)

[0198] Among them, PHE_U is the pressure under the furnace bed, obtained by sensor measurement; PIN is the pressure inside the furnace, obtained by sensor measurement; PNOFF is the pressure loss; and CPAT1 is the conversion coefficient parameter between the furnace bed pressure difference and the bed material height. Before the incinerator is put into use after leaving the factory, various commissioning tests will be carried out to confirm the values ​​of parameters such as PNOFF and CPAT1.

[0199] The furnace bed produces flue gas, but based on the specific heat capacity of the flue gas and the enthalpy of steam, there is a fixed correspondence between the flue gas flow rate and the steam flow rate. In this method, N represents the conversion coefficient between steam flow rate and flue gas flow rate under standard conditions: Flue gas flow rate = N * FN_U.

[0200] Real-time steam flow rate FN_U generated by incineration:

[0201]

[0202] Where DLA_U is the diameter of the steam pipe at maximum steam flow, DLA_L is the diameter of the steam pipe at minimum steam flow, ZN_U is the opening of the steam pressure regulating valve at maximum steam flow, and ZN_L is the opening of the steam pressure regulating valve at minimum steam flow; PSH is the steam pressure before the valve, and PN... U For real-time valve pressure loss, PN_U is the steam drum pressure at maximum steam flow, PN_L is the steam drum pressure at minimum steam flow, FDF is the steam operating flow rate, ACL7_U is the steam drum pressure correction coefficient (set according to boiler and steam drum type), ACL8_U is the upstream valve pressure correction coefficient, and APP_FDOFF is the steam flow deviation. Before the waste heat boiler is put into use after leaving the factory, various commissioning tests are conducted to confirm the values ​​of parameters such as APP_FDOFF. PNU and ACL8_U are the design values ​​for various types of valves.

[0203] After calculating the current material layer thickness PAT and the generated steam flow rate FN_U, the system is dynamically controlled by comparing them with preset target values. This ensures that the system's output steam flow rate is neither too high, which could lead to safety issues, nor too low, which could result in low production efficiency.

[0204] When it is found that the steam pressure output by the waste heat boiler 13 does not match the preset steam pressure, the steam pressure regulating valve 16 is first adjusted to investigate whether the discrepancy is caused by changes in the opening and closing of the steam pressure regulating valve 16, or by a mismatch between the heat supplied by the incinerator and the preset heat, resulting in an error in the steam pressure. Therefore, before step S8, the following steps are performed to confirm the relationship between the target value and the preset value of the output steam pressure:

[0205] a1: Calculate the steam pressure FNP corresponding to the preset steam flow rate FN and the steam pressure FN_UP corresponding to the real-time steam flow rate FN_U generated by incineration;

[0206] a2: Compare the relationship between FNP and FN_UP;

[0207] If FNP and FN_UP are equal, then proceed to step S8;

[0208] Otherwise, calculate the steam flow deviation FNCDEV:

[0209] FNCDEV=(FNCNOW-FNCSTN) / FNCSTN

[0210] Wherein, FNCDEV is the steam flow deviation; FNCNOW is the current value of the steam flow regulating valve; and FNCSTN is the steam flow reference value, which is the value corresponding to the output steam flow FN within the metering unit T.

[0211] a3: Adjust the steam flow regulating valve for the output steam of the incineration system:

[0212] If FNP > FN_UP, within the range [GNCCTL_MIN, GNCCTL_MAX], adjust the steam flow regulating valve to a smaller value according to the preset opening control table for the steam pressure regulating valve, and execute step a4;

[0213] If FNP < FN_UP, within the range [GNCCTL_MIN, GNCCTL_MAX], adjust the steam flow regulating valve to a larger value according to the preset opening control table for the steam pressure regulating valve, and execute step a4;

[0214] The opening control table for the steam pressure regulating valve stipulates the corresponding opening control values GNCCTL of the steam pressure regulating valve when the steam flow deviation FNCDEV takes different values, which are specifically as follows:

[0215] When FNCDEV ∈ (-∞, -15%), GNCCTL = GNCNOW + 15%;

[0216] When FNCDEV ∈ [-15%, -10%), GNCCTL = GNCNOW + 10%;

[0217] When FNCDEV ∈ [-10%, -5%), GNCCTL = GNCNOW + 5%;

[0218] When FNCDEV ∈ [-5%, 5%], GNCCTL = GNCNOW;

[0219] When FNCDEV ∈ (5%, 10%], GNCCTL = GNCNOW - 5%;

[0220] When FNCDEV ∈ (10%, 15%], GNCCTL = GNCNOW - 10%;

[0221] When FNCDEV ∈ (15%, ∞), GNCCTL = GNCNOW - 15%;

[0222] a4: Loop and execute steps a1 - a3;

[0223] If GNCCTL exceeds the range of [GNCCTL_MIN, GNCCTL_MAX] and FNP and FN_UP are still not equal, directly execute step S8;

[0224] Among them, GNCCTL_MIN and GNCCTL_MAX are respectively the minimum and maximum opening and closing values allowed for adjustment of the steam flow regulating valve in this system.

[0225] If it is determined that the reason for the excessive or insufficient steam pressure is not that the valve opening and closing of the steam pressure regulating valve 16 is too small or too large, but because the heat provided by the incinerator is in error from the preset, resulting in the steam generated by the waste heat boiler 13 not matching the preset total flow rate, then step S8 is executed.

[0226] In this method, based on the steam flow rate FN_U under the current furnace bed as the feedback of the combustion load and working conditions of the incinerator, by comparing the actual steam flow rate with the set value of the steam flow rate to judge the adjustment amount of other parameters, ensuring that the drying process of the sludge material proceeds according to the preset target. At the same time, taking the material thickness as the direct influencing factor for judging whether the process is accurately executed, and the combustion temperature as the indirect influencing factor for judging whether the process is accurately executed, and dynamically adjusting the feed rate of the incinerator and the air volume of the combustion-supporting air, ensuring that the combustion in the incinerator meets the requirements of the preset safe production on the basis of ensuring the incineration quality.

[0227] S8: Judge the relationship between the preset steam flow rate FN output within the measurement unit T and the steam flow rate FN_U under the current furnace bed;

[0228] If FN > FN_U, it means that the steam flow rate generated by the current combustion has not reached the preset value, and step S9 is executed;

[0229] If FN < FN_U, it means that the steam flow rate generated by the current combustion exceeds the preset steam supply value of the incinerator, and step S10 is executed;

[0230] If FN_U = FN, it means that the steam flow rate generated by the current combustion meets the preset value, and step S13 is executed.

[0231] S9: Simultaneously execute the following increasing operations to increase the steam flow rate FN output by the incinerator within the measurement unit T, and then execute step S11;

[0232] Increasing operation 1: Adjust the rotation speed SV of the spiral device for feeding the incinerator to make it larger;

[0233] Increasing operation 2: Adjust the secondary air flow rate to make it larger.

[0234] S10: Simultaneously execute the following decreasing operations to decrease the steam flow rate FN output by the incinerator within the measurement unit T, and then execute step S11;

[0235] Decreasing operation 1: Adjust the rotation speed SV of the spiral device for feeding the incinerator to make it smaller;

[0236] Decreasing operation 2: Adjust the secondary air flow rate to make it smaller.

[0237] S11: Judge the relationship between the current value of the material thickness value PAT and the preset working thickness TH of the sludge layer;

[0238] If PAT < TH, adjust the rotational speed SV of the screw device for feeding the incinerator to make it larger, and then execute step S12;

[0239] If PAT > TH, adjust the rotational speed SV of the screw device for feeding the incinerator to make it smaller, and then execute step S12;

[0240] If PAT = TH, execute step S12.

[0241] This method calculates the thickness of the material layer by measuring the differential pressure at both ends of the material layer in the incinerator. By controlling the rotational speed SV of the screw device for feeding the incinerator, the amount of material entering the incinerator is adjusted, thereby realizing the adjustment of the thickness of the material layer. Furthermore, the feeding amounts at multiple feeding points are adjusted. By controlling the thickness of the material layer, on the basis of ensuring production efficiency, it is also possible to prevent the furnace temperature from dropping due to insufficient or excessive material supply.

[0242] During the combustion process, it is necessary to control the temperature inside the furnace to be stable within a certain range, thereby maintaining the steam output of the waste heat boiler, ensuring the full combustion of the material and flue gas, and controlling the generation conditions of dioxins in the flue gas, and further reducing the flue gas pollutant emissions of the incinerator.

[0243] Step S12: Monitor and adjust the flue gas temperature and flue gas residence time inside the incinerator in real time to inhibit the generation of dioxins in the flue gas, specifically including the following steps:

[0244] d1: Set a temperature sensor at the flue gas outlet of the incinerator to monitor the flue gas outlet temperature Texit of the incinerator in real time;

[0245] d2: Calculate the flue gas residence time TR inside the incinerator at the current moment:

[0246]

[0247] Where, V is the volume of the dilute phase region of the incinerator as the secondary combustion chamber of the flue gas, FN_U is the steam flow rate output by the current incineration system, N is the conversion coefficient between the steam flow rate and the flue gas flow rate under standard conditions; Texit is the real-time flue gas outlet temperature of the incinerator;

[0248] N is a fixed value obtained based on the types of the combustion furnace and the preheating boiler.

[0249] Because, the flue gas flow rate = N * FN_U, and N is the conversion coefficient between the steam flow rate and the flue gas flow rate under standard conditions, so it is necessary to convert the flue gas flow rate to the value at the Celsius temperature Texit. The unit of the gas flow rate is liters per second, and the secondary combustion of the flue gas mainly occurs in the secondary combustion chamber, so the residence time of the flue gas in the secondary combustion chamber can be calculated through the flue gas flow rate and the volume of the secondary combustion chamber.

[0250] d3: Compare TR and dioxin inhibition time thresholds;

[0251] When TR ≤ dioxin inhibition time threshold:

[0252] Based on the formulas: flue gas flow rate = N * FN_U, FN = QR / H, and QR = (Wr + C * Fa)φ,

[0253] In practice, this method reduces the real-time steam flow rate by adjusting and lowering the value of the total calorific value (Wr) of the sludge input to the incinerator. This is achieved by reducing the amount of material fed into the incinerator per unit time and by reducing the secondary air volume along with the reduced feed rate per unit time. The reduction of flue gas flow rate is adjusted until TR > dioxin inhibition time threshold, which satisfies the flue gas residence time, at which point the reduction of Wr is stopped.

[0254] Otherwise, repeat steps d2 to d3.

[0255] In this embodiment, the dilute phase zone of the incinerator, i.e., the area above the secondary air inlet zone, serves as the secondary combustion chamber for flue gas. Thorough combustion of the flue gas and the control of dioxin generation conditions primarily occur within this secondary combustion chamber. To minimize dioxin generation in the furnace, the flue gas must be maintained at 850°C or higher for 2 seconds. Therefore, setting the dioxin suppression time threshold to 2 seconds means that the flue gas needs to be retained in the dilute phase zone for at least 2 seconds.

[0256] d4: Temperature sensors are installed at the inlet and outlet of the dilute phase zone of the incinerator to monitor the flue gas temperature Tsec in the secondary combustion chamber in real time.

[0257] When Tsec meets any of the following conditions, the auxiliary burner is activated and step d5 is executed;

[0258] Auxiliary burner activation condition 1: Tsec < 855℃

[0259] Auxiliary burner activation condition 2: Tsec < 860℃ for 5 consecutive minutes.

[0260] d5: After the auxiliary burner is turned on, after Tsec rises above 900°C, confirm whether Tsec meets the following conditions;

[0261] Auxiliary burner shutdown condition: Tsec > 880℃ for 5 consecutive minutes;

[0262] If the conditions are met, the auxiliary burner is turned off;

[0263] Otherwise, keep the auxiliary burner retracted until the conditions for shutting off the auxiliary burner are met.

[0264] d6: Repeatedly execute steps d2 to d4 to make the flue gas temperature and the flue gas residence time in the incinerator simultaneously meet the conditions for suppressing the generation of dioxins in the flue gas.

[0265] S13: Repeatedly execute steps S7 to S12 to continuously monitor the status of the incinerator and achieve dynamic control of the incinerator status.

[0266] To ensure complete combustion, it is also necessary to detect and control the oxygen concentration in the flue gas. Since the concentrations of CO and NOx in the flue gas are closely related to the oxygen concentration in the flue gas, once the combustion-supporting air (i.e., air) input into the incinerator is insufficient, the O2 concentration will decrease, which will in turn lead to incomplete combustion, and the contents of CO and NOx in the flue gas will increase. Therefore, it is necessary to control the oxygen concentration in the air to ensure complete combustion and then ensure that the flue gas meets the emission standards. Therefore, step S15 needs to be executed.

[0267] S15: When executing steps S2 to S14, continuously monitor and adjust the oxygen concentration in the incinerator to make the combustion in the incinerator meet the conditions for complete combustion. Specifically, it includes the following steps:

[0268] d1: Set the target oxygen content concentration range [SOmin, SOmax] of the flue gas of the incinerator according to the type of the sludge material dried and incinerated this time, where SOmin is the minimum value of the oxygen content concentration in the flue gas, and SOmax is the maximum value of the oxygen content concentration in the flue gas;

[0269] d2: Set an oxygen content analyzer for testing the oxygen concentration in the flue gas at the flue gas outlet of the incinerator, and continuously monitor the oxygen content St in the flue gas output by the incinerator;

[0270] d3: Confirm the relationship between St and the target oxygen content concentration;

[0271] When St < SOmin, adjust the secondary air flow rate to make it larger, and at the same time adjust the opening degree of the secondary air baffle;

[0272] When St > SOmax, adjust the secondary air flow rate to make it smaller, and at the same time adjust the opening degree of the secondary air baffle;

[0273] Otherwise, repeatedly execute steps d2 to d3.

[0274] In this method, the oxygen concentration in the flue gas is controlled and adjusted by adjusting the air flow rate of the secondary air to keep the oxygen concentration at the target oxygen content concentration. In this embodiment, the target oxygen content concentration is set to 6% - 9%, and it is continuously detected by the oxygen analyzer 10 set at the flue gas outlet 8 for testing the oxygen concentration in the flue gas.

[0275] By controlling the concentration of flue gas, the temperature and residence time of flue gas in the incinerator, and the oxygen concentration in the incinerator, it is ensured that the combustion of materials and flue gas in the incinerator can simultaneously achieve the following combustion levels:

[0276] High-temperature combustion, sufficient residence time, and high degree of mixing between air and flue gas;

[0277] This will ultimately achieve the goal of reducing the content of harmful substances in flue gas to meet emission standards, ensuring complete combustion, and maximizing energy conversion and utilization.

[0278] To achieve uninterrupted automatic feeding into the incinerator, this application incorporates a buffer chamber 5-1 and a weighing sensor 5-6 within it. The buffer chamber is equipped with high and low material levels. The weighing sensor 5-6 monitors the remaining material level in the buffer chamber 5-1 in real time. When the remaining material level reaches the low level, a feeding screw conveyor replenishes the buffer chamber 5-1; when the remaining material level reaches the high level, feeding stops. This automatic and continuous feeding of the buffer chamber without manual intervention ensures a continuous and automatic supply of material to the incinerator.

[0279] S14: Feeding material from the buffer bin to the incinerator using a screw conveyor for incinerator feeding;

[0280] While executing steps S2 to S13, the material height in the buffer bin is monitored in real time. When the material in the buffer bin reaches the high level, the replenishment of the buffer bin is stopped. When the material in the buffer bin reaches the low level, the material is replenished into the buffer bin.

[0281] The calculation method for the single replenishment amount FM of the buffer bin is as follows:

[0282] FM = CMHH - CML + n*SV*T

[0283] Wherein, CMHH is the total weight of the material in the buffer silo when it is at a high level; CML is the total weight of the material in the silo when it is at a low level; n is the relationship parameter between the rotation speed of the screw conveyor for incinerator feeding and the conveying capacity; SV is the rotation speed of the screw conveyor for incinerator feeding; and T is the single metering time.

[0284] In this application, the method for adjusting the rotational speed SV of the screw conveyor used for feeding the incinerator includes:

[0285] b1: Calculate the feed screw speed baseline value VSSTN:

[0286] VSSTN=SMSVS×VSAVE+(1-SMVSS)×VSSTN before

[0287] Where VSSTN is the reference value of the feed screw speed, SMSVS is the smoothing coefficient of the feed screw speed, VSAVE is the average value of the feed screw speed, and VSSTN is the average value of the feed screw speed. 前 The feed screw speed is the reference value before return;

[0288] b2: Calculate the combustion chamber temperature deviation TMCDEV:

[0289] TMCDEV = TMCNOW - TMCSTN

[0290] b3: Based on the temperature-rate correction table, determine the feed screw speed and combustion chamber temperature correction coefficient MVST.

[0291] The temperature-rate correction table records the values ​​of MVST when TMCDEV falls within different ranges.

[0292] When TMCDEV∈(-∞,-60), MVST=0.2;

[0293] When TMCDEV∈[-60,-20), MVST=-0.005×TMCDEV-0.1;

[0294] When TMCDEV∈[-20,20], MVST=0;

[0295] When TMCDEV∈(20,45], MVST=-0.008×TMCDEV+0.16;

[0296] When TMCDEV∈(45,∞), MVST=-0.2;

[0297] In practical applications, the working efficiency of an incinerator is related to the ambient temperature of the incinerator. Therefore, it is necessary to adjust the material feeding according to the current working temperature of the incinerator to ensure that the material can be fully burned.

[0298] b4: Calculate the feed screw speed control value:

[0299] VSCTL=(1+MVST)×VSSTN

[0300] Wherein, VSMIN≤VSCTL≤VSMAX, VSCTL is the feed screw speed control value, MVST is the feed screw speed combustion chamber temperature correction coefficient, VSMIN is the preset minimum feed screw speed, and VSMAX is the preset maximum feed screw speed;

[0301] b5: Each time the rotation speed SV of the screw conveyor used for feeding the incinerator is adjusted, the adjustment value is VSCTL. This ensures that the effect is not limited due to the feed rate being adjusted too small, nor that the incinerator material is not fully burned due to the feed rate being adjusted too large and other parameters not being updated in time.

[0302] Each time the secondary air flow rate is adjusted, to ensure that the secondary air is delivered to the incinerator as needed, and that excessively high or low air velocity does not adversely affect the combustion of materials within the incinerator, the opening of the secondary air damper must also be adjusted. The specific method for adjusting the secondary air damper opening includes the following steps:

[0303] c1: Calculate the reference value for the opening of the secondary air damper;

[0304] The secondary air damper opening reference values ​​include: the maximum opening reference value ZNUSTN when the air volume is large and the minimum opening reference value ZNLSTN when the air volume is small; the initial values ​​of ZNUSTN and ZNLSTN are set differently depending on the incinerator, and you can refer to the incinerator technical parameter table for details.

[0305] The calculation method is as follows:

[0306] When LHVSMS∈(0,2), ZNUSTN=60, ZNLSTN=20;

[0307] When LHVSMS∈[2,7], ZNUSTN=2×LHVSMS+56, ZNLSTN=3×LHVSMS+14;

[0308] When LHVSMS∈(7,∞), ZNUSTN=70; ZNLSTN=35;

[0309] LHVSMS is the calorific value of sludge material.

[0310] c2: Calculate the baffle opening correction value MZNPAT when the air volume is large;

[0311] When PATDEV∈(-∞,-20), MZNPAT=-6;

[0312] When PATDEV∈[-20,-6), MZNPAT=.5×PATDEV+3;

[0313] When PATDEV∈[-6,6], MZNPAT=0;

[0314] When PATDEV∈(6,20], MZNPAT=0.5×PATDEV-3;

[0315] When PATDEV∈(20,∞), MZNPAT=6;

[0316] PATDEV represents the combustion mode deviation.

[0317] PATDEV = PAT - MPATCTL;

[0318] Where PAT is the current value of the combustion mode, and MPATCTL is the reference value of the combustion mode.

[0319] c3: ZNUCTL, the control value for the opening of the secondary air damper when calculating large air volume;

[0320] ZNUCTL=ZNUSTN+MZNPAT

[0321] Wherein, ZNUSTN is the maximum reference value of the opening when the air volume is large; MZNPAT is the correction value for the damper opening when the air volume is large.

[0322] c4: Calculate the baffle opening correction value MZNTMC when the air volume is small;

[0323] When TMCDEV∈[-∞,20], MZNTMC=0;

[0324] When TMCDEV∈(20,50], MZNTMC=0.125×TMCDEV+2.5;

[0325] When TMCDEV∈(50,∞), MZNTMC=5;

[0326] Wherein, TMCDEV is the combustion chamber temperature deviation, calculated as follows:

[0327] TMCDEV = TMCNOW - TMCSTN;

[0328] Where TMCNOW is the current combustion chamber temperature and TMCSTN is the reference combustion chamber temperature;

[0329] c5: Calculate the secondary air damper opening control value ZNLCTL when the air volume is small;

[0330] ZNLCTL=ZNLSTN+MZNTMC

[0331] Wherein, ZNLSTN is the minimum reference value of the opening when the air volume is small, and MZNTMC is the correction value of the damper opening when the air volume is small;

[0332] c6: Construct a coordinate system with the horizontal axis representing air volume and the vertical axis representing the opening value; place the secondary air damper opening control value ZNLCTL for small air volume and the secondary air damper opening control value ZNUCTL for large air volume into the coordinate system, and draw a straight line passing through the two points, denoted as: opening control line;

[0333] c7: Obtain the secondary air flow rate that needs to be injected. On the opening control line, on the line segment between ZNLCTL and ZNUCTL, find the point that meets the secondary air flow rate and use it as the adjusted secondary air damper opening to ensure that the air volume entering from the secondary air inlet meets both the air volume required for combustion and the wind speed required for combustion.

[0334] After using the technical solution of this invention, continuous feeding and discharging of materials can be achieved through delayed continuous metering, with high metering accuracy. At the same time, it can realize the joint dynamic control of multiple parameters such as material feed rate, furnace temperature, bed thickness, waste heat boiler evaporation rate, combustion air intake rate of incinerator, and flue gas oxygen content, which improves the reliability of continuous and stable operation of incinerator, reduces human intervention, and has good adjustment performance.

Claims

1. A sludge drying incineration system control method characterized by, It comprises the following steps: S1: According to the type of the sludge material to be incinerated and dried this time, determine the sludge layer working thickness TH, working furnace temperature TEM and the output steam flow FN in the metering unit T required for the safe operation of the sludge drying and incineration system; S2: According to the preset output steam flow FN in the metering unit T, calculate the heat QR required for the incinerator to burn; FN = QR / H; Wherein, QR is the calorie unit MJ / H corresponding to the preset steam flow FN, and H is the enthalpy value unit MJ / KG of steam; S3: Calculate the single feeding amount FM of the incinerator according to the heat QR required for burning; QR = (Wr + C*Fa) φ; Wherein, the sludge material combustion heat Wr is the combustion heat value corresponding to the sludge feeding amount FM; φ is the thermal efficiency of the boiler, and C is the air heat enthalpy; The air combustion heat Fa is the heat value that can be provided after the air with the flow of FDFSTN is burned: FDFSTN = RAMDA × (CDFFST1 × LHVSMS + CDFFST2) × RESSTN; Wherein, FDFSTN is the air flow required for the sludge feeding amount FM to burn in the furnace, RAMDA is the air excess rate, LHVSMS is the combustion heat value of the sludge material, RESSTN is the material input amount of the sludge material, RESSTN is initially valued as the initial single feeding amount FM of the feeding system; CDFFST1 is the theoretical air conversion coefficient required for the combustion of heat-releasing material in the sludge; CDFFST2 is the theoretical air conversion coefficient parameter required for the oxidation of non-heat-releasing material in the sludge; S4: Based on FM, calculate the speed SV of the screw equipment for feeding the incinerator of the sludge drying and incineration system in the metering unit T; SV = FM / (n*T) Wherein, FM is the sludge feeding amount required to be supplied to the incinerator per unit time T; n is the relationship parameter between the speed of the screw equipment for feeding the incinerator and the conveying amount, which is the self-coefficient of the screw equipment; T is the single metering time; S5: Calculate the primary air flow and the secondary air flow required for burning of the sludge drying and incineration system; Primary air flow = Secondary air flow = FDFSTN*50%; S6: After starting the incinerator, supply air to the incinerator according to the primary air flow and the secondary air flow, and control the screw equipment for feeding the incinerator to supply material to the incinerator at the speed SV; S7: During the burning process, calculate the material layer thickness PAT and the generated steam flow FN_U by measuring the differential pressure of the material layer at both ends of the incinerator and the input air flow of the incinerator; The material thickness value PAT under the current burning mode: PAT = CPAT1 × (PHE_U - PIN - PNOFF) Wherein, PHE_U is the pressure under the furnace bed, PIN is the pressure in the furnace, PNOFF is the pressure loss, and CPAT1 is the conversion coefficient parameter of the furnace bed pressure difference and the bed material height; The real-time steam flow FN_U generated by burning: Wherein, DLA_U is the steam pipeline diameter at the maximum steam flow, DLA_L is the steam pipeline diameter at the minimum steam flow, ZN_U is the opening of the steam pressure regulating valve at the maximum steam flow, ZN_L is the opening of the steam pressure regulating valve at the minimum steam flow; PSH is the steam pressure before the valve, PN U is the pressure loss of the valve, PN_U is the drum steam pressure at the maximum steam flow, PN_L is the drum steam pressure at the minimum steam flow, FDF is the steam working condition flow, ACL7_U is the drum steam pressure correction coefficient, ACL8_U is the steam pressure before the valve correction coefficient, APP_FDOFF is the steam flow deviation; ACL7_L is the drum steam pressure correction coefficient at the minimum steam flow; S8: Judge the relationship between the preset output steam flow FN in the metering unit T and the current burning generated steam flow FN_U. If FN>FN_U, the current combustion generated steam flow does not reach the preset value, step S9 is executed; If FN<FN_U, the current combustion generated steam flow exceeds the preset incinerator steam providing preset value, step S10 is executed; If FN_U=FN, the current combustion generated steam flow meets the preset value, step S13 is executed; S9: the following increasing operation is performed to increase the incinerator output steam flow FN in the measurement unit T, and then step S11 is executed; Increasing operation 1: the rotation speed SV of the incinerator feeding screw device is adjusted to be larger; Increasing operation 2: the secondary air flow is adjusted to be larger; S10: the following decreasing operation is performed to decrease the incinerator output steam flow FN in the measurement unit T, and then step S11 is executed; Decreasing operation 1: the rotation speed SV of the incinerator feeding screw device is adjusted to be smaller; Decreasing operation 2: the secondary air flow is adjusted to be smaller; S11: the relationship between the current value of the material thickness value PAT and the preset sludge layer working thickness TH is judged; If PAT<TH, the rotation speed SV of the incinerator feeding screw device is adjusted to be larger, and then step S12 is executed; If PAT>TH, the rotation speed SV of the incinerator feeding screw device is adjusted to be smaller, and then step S12 is executed; If PAT=TH, step S12 is executed; S12: the flue gas temperature and flue gas residence time in the incinerator are monitored and adjusted in real time to inhibit the generation of dioxin in the flue gas; S13: steps S7-S12 are cyclically executed to uninterruptedly monitor the incinerator state and realize dynamic control of the incinerator state; S14: the incinerator feeding screw device feeds the incinerator from the buffer bin; the buffer bin is provided with a high material level and a low material level; While steps S2-S13 are executed, the material height of the buffer bin is monitored in real time and in parallel, feeding of the buffer bin is stopped when the material in the buffer bin reaches the high material level, and the buffer bin is fed when the material in the buffer bin reaches the low material level; The calculation method of the single feeding amount FM of the buffer bin each time is as follows: FM=CMHH-CML+n*SV*T Wherein, CMHH is the total weight of the material in the buffer bin when the material is at the high material level; CML is the total weight of the material in the buffer bin when the material is at the low material level; n is the relationship parameter between the rotation speed of the incinerator feeding screw device and the conveying amount; SV is the rotation speed of the incinerator feeding screw device; T is the single measurement time.

2. The control method of the sludge drying and incinerating system according to claim 1, wherein: Before step S8 is executed, the following steps are executed to confirm the relationship between the target value and the preset value of the output steam pressure: a1: the steam pressure FNP corresponding to the preset steam flow FN and the steam pressure FN_UP corresponding to the current bed steam flow FN_U are calculated; a2: the relationship between FNP and FN_UP is compared; If FNP and FN_UP are equal, step S8 is executed; Otherwise, the steam flow deviation FNCDEV is calculated: FNCDEV=(FNCNOW-FNCSTN) / FNCSTN Among them, FNCDEV is the steam flow deviation; FNCNOW is the current value of the steam flow regulating valve; FNCSTN is the steam flow reference value, and its value is the value corresponding to the steam flow FN output within the measurement unit T; a3: Adjust the steam flow regulating valve of the output steam of the incineration system: If FNP > FN_UP, within the range of [GNCCTL_MIN, GNCCTL_MAX], according to the preset opening control table of the steam pressure regulating valve, turn down the steam flow regulating valve, and execute step a4; If FNP < FN_UP, within the range of [GNCCTL_MIN, GNCCTL_MAX], according to the preset opening control table of the steam pressure regulating valve, turn up the steam flow regulating valve, and execute step a4; The opening control table of the steam pressure regulating valve stipulates the opening control value GNCCTL of the steam pressure regulating valve corresponding to different values of the steam flow deviation FNCDEV; a4: Loop and execute steps a1 to a3; If GNCCTL exceeds the range of [GNCCTL_MIN, GNCCTL_MAX] and FNP and FN_UP are still not equal, directly execute step S8; Among them, GNCCTL_MIN and GNCCTL_MAX are respectively the minimum and maximum opening values allowed for adjustment of the steam flow regulating valve in this system.

3. The control method of the sludge drying and incinerating system according to claim 1, wherein: The method for adjusting the rotation speed SV of the screw device for feeding the incinerator includes: b1: Calculate the feed screw speed reference value VSSTN: VSSTN = SMSVS × VSAVE + (1 - SMSVS) × VSSTN previous Among them, VSSTN is the feed screw speed reference value, SMSVS is the feed screw speed smoothing coefficient, VSAVE is the average value of the feed screw speed, and VSSTN previous is the previous return value of the feed screw speed reference; b2: Calculate the combustion chamber temperature deviation TMCDEV: TMCDEV = TMCNOW - TMCSTN; Among them, TMCNOW is the current value of the combustion chamber temperature, and TMCSTN is the combustion chamber temperature reference value; b3: Based on the temperature - speed correction correspondence table, judge the combustion chamber temperature correction coefficient MVST of the feed screw speed: The temperature - speed correction correspondence table records the values of MVST corresponding to different ranges of TMCDEV; When TMCDEV ∈ (-∞, -60), MVST = 0.2; When TMCDEV ∈ [-60, -20), MVST = -0.005 × TMCDEV - 0.1; When TMCDEV ∈ [-20, 20], MVST = 0; When TMCDEV ∈ (20, 45], MVST = -0.008 × TMCDEV + 0.16; When TMCDEV ∈ (45, ∞), MVST = -0.2; b4: Calculate the feed screw speed control value: VSCTL = (1 + MVST) × VSSTN Wherein, VSMIN≤VSCTL≤VSMAX, VSCTL is the control value of the screw speed, MVST is the correction coefficient of the screw speed for the combustion chamber temperature, VSMIN is the preset minimum value of the screw speed, and VSMAX is the preset maximum value of the screw speed. b5: each time the speed SV of the screw device for feeding the incinerator is adjusted, the value of each adjustment is VSCTL.

4. The method of claim 1, wherein: When the secondary air flow is adjusted, the opening of the secondary air baffle must be adjusted at the same time, and the adjustment method of the opening of the secondary air baffle comprises the following steps. c1: calculating the opening reference value of the secondary air baffle; The opening reference value of the secondary air baffle comprises: the maximum reference value ZNUSTN of the opening at large air volume and the minimum reference value ZNLSTN of the opening at small air volume. The calculation method is as follows: When LHVSMS∈(0,2), ZNUSTN=60 and ZNLSTN=20; When LHVSMS∈[2,7], ZNUSTN=2×LHVSMS+56 and ZNLSTN=3×LHVSMS+14; When LHVSMS∈(7,∞), ZNUSTN=70 and ZNLSTN=35; LHVSMS is the combustion heat value of the sludge material. c2: calculating the opening correction value MZNPAT of the baffle at large air volume. When PATDEV∈(-∞,-20), MZNPAT=-6; When PATDEV∈[-20,-6), MZNPAT=.5×PATDEV+3; When PATDEV∈[-6,6], MZNPAT=0; When PATDEV∈(6,20], MZNPAT=0.5×PATDEV-3; When PATDEV∈(20,∞), MZNPAT=6; Wherein, PATDEV is the deviation of the combustion mode, PATDEV=PAT-MPATCTL; Wherein, PAT is the material thickness value in the current combustion mode, and MPATCTL is the reference value of the combustion mode. c3: calculating the opening control value ZNUCTL of the secondary air baffle at large air volume. ZNUCTL=ZNUSTN+MZNPAT Wherein, ZNUSTN is the maximum reference value of the opening at large air volume, and MZNPAT is the opening correction value of the baffle at large air volume. c4: calculating the opening correction value MZNTMC of the baffle at small air volume. When TMCDEV∈[-∞,20], MZNTMC=0; When TMCDEV∈(20,50], MZNTMC=0.125×TMCDEV+2.5; When TMCDEV∈(50,∞), MZNTMC=5; Wherein, TMCDEV is the deviation of the combustion chamber temperature, and the calculation method is as follows: TMCDEV=TMCNOW-TMCSTN; Wherein, TMCNOW is the current value of the combustion chamber temperature, and TMCSTN is the reference value of the combustion chamber temperature. c5: calculating the opening control value ZNLCTL of the secondary air baffle at small air volume. ZNLCTL=ZNLSTN+MZNTMC Wherein, ZNLSTN is the minimum reference value of the opening at small air volume, and MZNTMC is the correction value of the damper opening at small air volume. c6: A coordinate system is constructed with the horizontal coordinate as the air volume and the vertical coordinate as the opening value. The secondary air damper opening control value ZNLCTL at small air volume and the secondary air damper opening control value ZNUCTL at large air volume are placed in the coordinate system, and a straight line passing through the two points is drawn, which is denoted as: the opening control line. c7: Obtain the current required secondary air flow, and find the point on the line segment between ZNLCTL and ZNUCTL on the opening control line that satisfies the secondary air flow as the adjusted secondary air damper opening.

5. The method of claim 1, wherein: In step S12, the temperature and residence time of the flue gas in the incinerator are monitored and adjusted in real time to inhibit the generation of dioxin in the flue gas, which specifically includes the following steps: d1: A temperature sensor is arranged at the flue gas outlet of the incinerator to monitor the flue gas outlet temperature Texit of the incinerator in real time; d2: Calculate the flue gas residence time TR in the incinerator at the current time: Wherein, V is the volume of the dilute phase zone of the flue gas secondary combustion chamber of the incinerator, FN_U is the current steam flow output by the incineration system, N is the conversion coefficient of steam flow and flue gas flow under standard conditions; Texit is the real-time flue gas temperature at the outlet of the incinerator; d3: Compare TR and the dioxin inhibition time threshold value; When TR≤the dioxin inhibition time threshold value, reduce the amount of FN_U until TR>the dioxin inhibition time threshold value; Otherwise, steps d2-d3 are executed in a loop; d4: Real-time monitoring of the flue gas temperature Tsec in the flue gas secondary combustion chamber; When Tsec meets any of the following conditions, the auxiliary burner is started, and step d5 is executed; Auxiliary burner opening condition 1: Tsec<855℃ Auxiliary burner opening condition 2: Tsec<860℃ for 5 consecutive minutes; d5: After the auxiliary burner is started, if Tsec rises above 900℃, it is determined whether Tsec meets the following condition: Auxiliary burner closing condition: Tsec>880℃ for 5 consecutive minutes; If yes, the auxiliary burner is closed; Otherwise, the auxiliary burner is kept open until the auxiliary burner closing condition is met; d6: Steps d2-d4 are executed in a loop to make the flue gas temperature and residence time in the incinerator meet the condition of inhibiting the generation of dioxin in the flue gas.

6. The method of claim 1, wherein: It further includes the following steps: S15: When steps S2-S14 are executed, the oxygen concentration in the incinerator is monitored and adjusted in real time to make the combustion in the incinerator meet the sufficient combustion condition, which specifically includes the following steps d1: According to the type of sludge material to be dried by this incineration, set the target oxygen content concentration range [SOmin, SOmax] of the flue gas of the incinerator, wherein SOmin is the minimum value of the oxygen content concentration in the flue gas, and SOmax is the maximum value of the oxygen content concentration in the flue gas; d2: An oxygen content meter for testing the oxygen concentration in the flue gas is arranged at the flue gas outlet of the incinerator, and the oxygen content St in the flue gas output by the incinerator is monitored in real time; d3: Determine the relationship between St and the target oxygen content concentration; When St<SOmin, adjust the secondary air flow to be larger, and adjust the secondary air baffle opening degree at the same time; When St>SOmax, adjust the secondary air flow to be smaller, and adjust the secondary air baffle opening degree at the same time; Otherwise, repeat steps d2-d3.

7. The method of claim 1, wherein: The buffer bin is initially started to feed the spiral device, and the spiral device for feeding needs to be calibrated; The calibration method of the feeding amount per unit time of the spiral device for feeding includes the following steps: e1: A spiral device for feeding and a scraper are arranged between the dry sludge bin for storing materials and the buffer bin, Based on the spiral device for feeding transporting to the buffer bin, and based on the scraper sending the sludge on the spiral device for feeding into the buffer bin; e2: The frequency of the spiral device for feeding is set as SupN; The spiral device for feeding and the scraper are operated at the same time; e3: Based on the frequency SupN, feeding the buffer bin until the material level of the buffer bin reaches the high material level, recording the running time of the spiral device for feeding as SupT1, and measuring the total amount of materials in the buffer bin at this time as SupW1; e5: Stop the spiral device for feeding; e6: Continuously confirm the change of the total weight of the materials in the buffer bin until the total weight of the materials in the buffer bin stops changing, record the total amount of materials at this time as SupW2; e7: Calculate the feeding amount per unit time SupQ of the spiral device for feeding when the frequency is SupN, and the sludge storage weight SccW of the scraper: SupQ=SupW2 / SupT1; SccW≈SupW2-SupW1.

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