Magnetic suspension combustion-supporting and cooling fan energy-saving control method and system for double-chamber lime kiln

Abstract

The invention relates to the technical field of intelligent energy-saving control of industrial kilns, in particular to a magnetic suspension combustion-supporting and cooling fan energy-saving control system, method and equipment for a double-hearth lime kiln. The method comprises the following steps: initially setting a magnetic suspension combustion-supporting and cooling fan working mode of the double-hearth lime kiln; based on the synchronous power generation mode, magnetic suspension combustion supporting and a cooling fan of the double-hearth lime kiln are subjected to pressure relief; based on an energy grading feedback strategy, a dual-channel IGBT inverter and a super capacitor bank are respectively used for electric energy feedback and off-grid power supply; adjusting the rotating speed of the fan based on a dynamic frequency conversion control strategy to realize cubic matching of power and the rotating speed; the magnetic suspension combustion-supporting and cooling fan switching quick response of the double-hearth lime kiln is carried out based on the rotary inertia of the lightweight rotor; safety protection is carried out in the switching process of the double-hearth lime kiln based on a safety protection mechanism; and power generation control is carried out based on rotor speed reduction fast response. According to the technical scheme, energy conservation and consumption reduction can be effectively achieved, and energy waste is reduced; meanwhile, quick response is achieved, and dynamic change is met.

Description

Technical Field

[0001] This invention relates to the field of intelligent energy-saving control technology for industrial kilns, and in particular to an energy-saving control method and system for magnetic levitation combustion and cooling fans in a double-chamber lime kiln. Background Technology

[0002] Double-chamber lime kilns, as the core equipment of the modern lime industry, are widely used in the fields of metallurgy, chemical industry and building materials. They achieve continuous production through the periodic switching of thermal states between the A and B kiln chambers.

[0003] During the kiln switching process, the high-pressure gas in the combustion chamber needs to be quickly released through the vent valve group on the combustion air duct and cooling air duct to reduce the chamber pressure to atmospheric pressure and balance the pressure. During the rotor deceleration process, due to the excessively long deceleration time, the momentum power released per unit time is too low to reach the inverter's start-up threshold. The rotor's kinetic energy is dissipated as heat in the braking resistor and cannot be converted into recoverable electrical energy, thus failing to generate electricity.

[0004] Furthermore, traditional double-chamber lime kilns use ordinary fans with large rotor inertia. It takes 30-50 seconds or more to decelerate from 25,000rpm to 10,000rpm. During the deceleration process, braking energy is consumed by braking resistors, and the electrical energy converted from rotor kinetic energy is not recovered. At the same time, high-power operation is maintained during the depressurization stage, with the total power consumption of the two fans reaching 555kW, resulting in a large amount of energy waste and making it impossible to generate electricity.

[0005] Meanwhile, existing dual-chamber lime kiln switching schemes cannot meet the transient response requirements of rapid switching. When the frequency is rapidly reduced, the back electromotive force of the motor causes a sudden increase in the DC bus voltage. Furthermore, traditional schemes rely on braking resistors to consume energy, which exacerbates energy waste. Since existing technologies cannot meet the process requirements of rapid switching of dual-chamber lime kilns, the chamber pressure fluctuates greatly during the switching phase, affecting the quality of lime products.

[0006] Finally, traditional control methods fail to take into account the precise matching relationship between fan speed and actual load. The combustion fan and cooling fan are controlled independently. Under low load conditions, the fans still maintain a fixed power operation, which undoubtedly causes a lot of energy waste and greatly increases the production cost of enterprises.

[0007] Based on the above technical problems, there is an urgent need for an energy-saving control method and system for magnetic levitation combustion and cooling fans in double-chamber lime kilns. Summary of the Invention

[0008] The purpose of this invention is to provide an energy-saving control system, method, and equipment for a magnetic levitation combustion and cooling fan in a double-chamber lime kiln. This invention focuses on an energy-saving optimization control method for the combustion-cooling process system of a dual 300kW magnetic levitation centrifugal blower unit in a double-chamber lime kiln. This method pays particular attention to the dynamic coordinated control of the blower unit during the switching process of the double-chamber lime kiln, the efficient recovery of braking energy, the wide-condition adaptive frequency conversion adjustment, and the dynamic matching of the lightweight rotor-bearing system, aiming to significantly improve system energy efficiency and reduce operating energy consumption.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] In a first aspect, a method for energy-saving control of magnetic levitation combustion and cooling fans in a double-chamber lime kiln includes:

[0011] The initial setting is the magnetic levitation combustion and cooling fan working mode for the double-chamber lime kiln;

[0012] Rapid depressurization of the magnetic levitation combustion and cooling fan in a double-chamber lime kiln based on synchronous power generation mode;

[0013] Based on the energy graded feedback strategy, dual-channel IGBT inverters and supercapacitor banks are used for energy feedback and off-grid power supply, respectively.

[0014] The fan speed is adjusted based on a dynamic frequency conversion control strategy to achieve a cubic match between power and speed.

[0015] Rapid response for switching of magnetic levitation combustion and cooling fans in a double-chamber lime kiln based on lightweight rotor rotational inertia;

[0016] Safety protection is implemented during the switching process of a dual-chamber lime kiln based on a safety protection mechanism.

[0017] Power generation control is based on rapid response to rotor speed reduction.

[0018] Furthermore, the initial setting of the magnetic levitation combustion and cooling fan operating mode for the double-chamber lime kiln includes using kiln A for high-temperature calcination and kiln B for preheating and cooling. During high-temperature calcination in kiln A, the combustion fan speed is stabilized at 25,000 rpm with a power consumption of 285 kW, and the air volume is dynamically adjusted based on an oxygen content sensor. During preheating and cooling in kiln B, the cooling fan speed is 25,000 rpm with a power consumption of 270 kW, and the calcination stage lasts for 13 minutes. Simultaneously, during the switching preparation stage, the combustion fan begins to slow down by closing the fuel valve in kiln A; at the same time, the vent valve is opened to release high-pressure gas for depressurization, synchronously reducing the speed of both the combustion and cooling fans to 10,000 rpm, generating electricity and feeding back energy.

[0019] Furthermore, the rapid depressurization of the magnetic levitation combustion and cooling fans in the dual-chamber lime kiln based on synchronous power generation includes, during the depressurization phase, the combustion and cooling fans synchronously switch to generator mode via CAN bus, completing a speed reduction from 25,000 rpm to 10,000 rpm within 15 seconds. During this process, the total power generation energy is 9210 kJ, or 2.56 kWh / cycle. Converted to kilowatt-hours (kWh), this is expressed as: 9210 ÷ 3600 = 2.56 kWh / cycle, where the inertia J of the carbon fiber composite rotor is 1.6 kg·m. 2 , is represented as:

[0020] Furthermore, the energy-graded feedback strategy utilizes a dual-channel IGBT inverter and a supercapacitor bank for energy feedback and off-grid power supply, respectively. This includes converting 2.05 kWh / cycle of energy into 380V / 50Hz AC power via the dual-channel IGBT inverter to feed back to the grid, reducing the cost of purchased electricity; the remaining 0.51 kWh / cycle of energy is stored in a 100F supercapacitor bank for off-grid power supply to cool the system, reducing dependence on the grid during switching. The supercapacitor bank operates at 750V.

[0021] Furthermore, the dynamic frequency conversion control strategy for adjusting the fan speed to achieve a cubic match between power and speed includes adjusting the fan speed in real time according to the kiln state during the depressurization process to achieve a cubic match between power and speed, thus significantly reducing energy consumption. Specifically, during the depressurization stage, the total power consumption of the two fans decreased from 555kW to 35.52kW, with an energy saving rate of 93.6%. The power consumption is expressed as follows:

[0022]

[0023] Where: P 助燃 P represents the actual power consumption of the combustion fan at its lowest speed. 额1 P represents the actual power consumption of the combustion fan at its rated speed. 冷却 P represents the actual power consumption of the cooling fan at its lowest speed. 额2 n is the actual power consumption of the cooling fan at its rated speed; n1 is the minimum speed of the combustion fan after speed reduction; n 额1 n1 is the rated speed of the combustion fan; n2 is the minimum speed of the cooling fan after speed reduction; n 额2 This is the rated speed of the cooling fan.

[0024] Furthermore, the rapid response of the magnetic levitation combustion and cooling fan switching of the dual-chamber lime kiln based on the rotational inertia of the lightweight rotor includes switching chamber A to the cooling chamber and accelerating the cooling fan to 25,000 rpm; switching chamber B to the calcination chamber and accelerating the combustion fan to 25,000 rpm. The entire process lasts from 13 minutes and 15 seconds to 15 minutes. From 15 minutes, a stable operation phase begins, and the next operating cycle begins, i.e., calcination in chamber B, cooling in chamber A, with the combustion fan operating at 10k to 25k rpm and the cooling fan operating at 10k to 25k rpm.

[0025] Furthermore, the rapid response based on lightweight rotor inertia includes the use of a carbon fiber composite rotor with an inertia J = 1.6 kg·m. 2 (50% reduction compared to traditional steel rotors) meets the requirement of reducing speed from 25,000 rpm to 10,000 rpm and increasing speed within 15 seconds.

[0026] Furthermore, the safety protection mechanism implemented during the switching process of the dual-chamber lime kiln includes: real-time monitoring of flow and pressure curves to trigger frequency adjustment to suppress surge, thereby achieving surge suppression; maintaining voltage stability within the allowable fluctuation range through a bidirectional DC / DC module, thereby achieving bus voltage stabilization; and emergency shutdown in case of temperature exceeding limits or pressure sudden changes, thereby achieving fault interlocking.

[0027] Secondly, an energy-saving control system for a magnetic levitation combustion and cooling fan in a double-chamber lime kiln includes:

[0028] The double-chamber lime kiln, lightweight rotor bearing system, and magnetic levitation blower unit are connected to the double-chamber lime kiln to form a magnetic levitation combustion and cooling fan for the double-chamber lime kiln; the output end of the magnetic levitation combustion and cooling fan for the double-chamber lime kiln is connected to the input end of the lightweight rotor bearing system.

[0029] The lightweight rotor bearing system includes: a carbon fiber composite rotor and a five-degree-of-freedom magnetic levitation bearing; the carbon fiber composite rotor includes a main shaft, a radial rotor core assembly, magnets, a carbon fiber sheath, a thrust disk, and an axial sensor detection disk; the main shaft is connected to the radial rotor core assembly, magnets, carbon fiber sheath, thrust disk, and axial sensor detection disk; the carbon fiber sheath is connected to the magnets; and the thrust disk is connected to the axial sensor detection disk.

[0030] Furthermore, the output end of the combustion-supporting magnetic levitation blower is connected to the input end of the first cylinder, the input end of the first temperature sensor, the input end of the first pressure sensor, and the input end of kiln chamber A, respectively; wherein, the output end of the first cylinder is connected to the input end of the first venting silencer, and the output end of the first venting silencer is connected to the first vent outlet; the output end of the cooling magnetic levitation blower is connected to the input end of the second temperature sensor, the input end of the second cylinder, the input end of the second pressure sensor, the input end of the third switching valve, and the input end of the fourth switching valve, respectively; the output end of the second cylinder is connected to the input end of the second venting silencer, and the output end of the second venting silencer is connected to the second vent outlet; the output end of the third switching valve is connected to the input end of kiln chamber A; and the output end of the fourth switching valve is connected to the input end of kiln chamber B.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. Compared to the 30-50s response time of traditional wind turbines in existing technologies, this invention achieves a rotor deceleration from 25,000rpm to 10,000rpm in 15 seconds, while significantly shortening the rotor switching preparation stage. It realizes the conversion of rotor momentum into electrical energy and power generation in a short time, solving the problem of wasted electrical energy during rotor deceleration and inability to generate electricity in traditional processes. Moreover, each switching control can recover electrical energy through feedback to the grid, and some electrical energy is stored in a supercapacitor for off-grid use. Under long-term operation, it can reduce a lot of electricity expenses and reduce carbon emissions, thus combining economic benefits and environmental value.

[0033] 2. This invention achieves cubic matching between fan power and speed through a dynamic frequency conversion control strategy, significantly reducing the total power consumption of the two fans during the pressure relief phase. At the same time, it suppresses surge by adjusting the speed, enabling rapid rotor deceleration. By adopting a carbon fiber composite rotor, the moment of inertia is significantly reduced compared to traditional steel rotors, allowing for rapid deceleration and reverse speed increase of the fan in a short time. This meets the rapid cycle switching requirements of the dual-chamber lime kiln, avoiding the problem of slow deceleration and no power generation in traditional technical solutions, resulting in significant energy-saving effects.

[0034] 3. A multi-layered safety protection mechanism enables comprehensive risk control, real-time monitoring of flow and pressure curves, and triggering frequency adjustments to suppress surge and stabilize the bus voltage within the allowable fluctuation range; automatic emergency shutdown is implemented in case of temperature exceeding limits or sudden pressure changes. This effectively solves the problems of sudden bus voltage rise and frequent surge caused by rapid frequency reduction in traditional solutions, significantly reducing equipment failure probability and maintenance costs, effectively avoiding dependence on grid fluctuations, and reducing energy supply and demand instability during switching processes. Attached Figure Description

[0035] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0036] Figure 1 This is a schematic diagram of the system structure of the present invention.

[0037] Figure 2 This is a schematic diagram of the carbon fiber composite rotor of the present invention.

[0038] Figure 3 This is a schematic diagram of the method flow of the present invention.

[0039] Figure 4 This is a schematic diagram of the device connection of the present invention.

[0040] Figure 5 This is a timing diagram of the control logic of the present invention.

[0041] Figure 6 This is a schematic diagram of the double-shaft extension double impeller structure of the present invention.

[0042] In the diagram: 1-Main shaft, 2-Radial rotor core assembly, 3-Magnet, 4-Carbon fiber sheath, 5-Thrust disc, 6-Axial sensor detection disc. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] Example 1, as Figure 1 As shown

[0045] An energy-saving control system for a magnetic levitation combustion and cooling fan in a double-chamber lime kiln, including...

[0046] Magnetic levitation blower unit; double-chamber lime kiln; energy feedback and storage system; dynamic frequency conversion control system for switching process; safety and protection mechanism system;

[0047] The magnetic levitation blower unit is connected to the double-chamber lime kiln to form a magnetic levitation combustion and cooling blower for the double-chamber lime kiln.

[0048] The output of the magnetic levitation combustion and cooling fan of the double-chamber lime kiln is connected to the input of the energy feedback and storage system, the dynamic frequency conversion control system for the switching process, and the safety and protection mechanism system, respectively.

[0049] It also includes a lightweight rotor bearing system; the output end of the magnetic levitation combustion and cooling fan for the double-chamber lime kiln is connected to the input end of the lightweight rotor bearing system;

[0050] The lightweight rotor bearing system includes: a carbon fiber composite rotor and a five-degree-of-freedom magnetic levitation bearing;

[0051] like Figure 2As shown, the carbon fiber composite rotor includes a main shaft 1, a radial rotor core assembly 2, a magnet 3, a carbon fiber sheath 4, a thrust disk 5, and an axial sensor detection disk 6.

[0052] The main shaft 1 is connected to the radial rotor core assembly 2, magnet 3, carbon fiber sheath 4, thrust disk 5, and axial sensor detection disk 6;

[0053] Carbon fiber sheath 4 connects to magnet 3;

[0054] The thrust plate 5 is connected to the axial sensor detection plate 6.

[0055] The energy feedback and storage system is specifically as follows:

[0056] Synchronous power generation mode:

[0057] During the depressurization phase (13-13 minutes 15 seconds), the combustion and cooling fans synchronously switch to generator mode via the Controller Area Network (CAN) bus, and complete the speed reduction (from 25,000 rpm to 10,000 rpm) within a certain time (15 seconds). During this process, the total power generation energy is 9210 kJ, or 2.56 kWh / cycle.

[0058] The formula for generating electricity in this process is:

[0059] ΔE 总 =J(ω1) 2 -ω2 2 )×2=9210(kJ)J is the moment of inertia, specifically 1.6kg·m 2 ω1 is the angular velocity corresponding to the highest speed (25,000 rpm), and ω2 is the angular velocity corresponding to the lowest speed (10,000 rpm) after deceleration.

[0060] ΔE is calculated from the formula for generating electricity. 总 = 9210 (kJ)

[0061] Converted to kilowatt-hours (kWh): 9210 ÷ 3600 = 2.56 kWh / time

[0062] The carbon fiber composite rotor has a 50% lower moment of inertia than the traditional steel rotor, with a moment of inertia J of 1.6 kg·m. 2

[0063]

[0064] Energy tiered feedback strategy:

[0065] A portion of the 2.05 kWh / cycle electrical energy is converted into 380V / 50Hz AC power and fed back to the grid by a dual-channel insulated gate bipolar transistor (IGBT) inverter (efficiency ≥97%), thereby reducing the cost of externally purchased electricity for enterprises.

[0066] The remaining 0.51 kWh / cycle of electrical energy is stored in a 100F capacitor bank (operating voltage 750V) for off-grid power supply to the cooling system, reducing dependence on the grid during switching.

[0067] The dynamic frequency conversion control system for the switching process is specifically as follows:

[0068] Power and speed are matched cubically:

[0069] The fan speed is adjusted in real time according to the kiln condition to achieve a cubic match between power and speed, which significantly reduces energy consumption. During the depressurization stage, the total power consumption of the two fans is reduced (from 555kW to 35.52kW, with an energy saving rate of up to 93.6%).

[0070]

[0071] Where: P 助燃 P represents the actual power consumption of the combustion fan at its lowest speed (10000 rpm); 额1 P represents the actual power consumption of the combustion fan at its rated speed (25000 rpm); 冷却 P represents the actual power consumption of the cooling fan at its lowest speed (10000 rpm); 额2 This represents the actual power consumption of the cooling fan at its rated speed (25000 rpm).

[0072] n1 is the lowest speed (10,000 rpm) after the combustion fan is reduced in speed; 额1 n1 is the rated speed of the combustion fan (25,000 rpm); n2 is the minimum speed of the cooling fan after speed reduction (10,000 rpm); n 额2 The rated speed of the cooling fan is 25,000 rpm.

[0073] Lightweight rotor for fast response:

[0074] A carbon fiber composite rotor is used, with a moment of inertia J = 1.6 kg·m. 2 (50% reduction compared to traditional steel rotors) meets the requirement of reducing speed from 25,000 rpm to 10,000 rpm and increasing speed from 10,000 rpm to 25,000 rpm within a certain time (15 seconds).

[0075] The security and protection mechanism is as follows:

[0076] Surge suppression: Real-time monitoring of flow and pressure curves triggers frequency adjustment (+2Hz) to suppress surge;

[0077] Bus voltage stabilization: The bidirectional DC / DC module maintains the voltage stable within the allowable fluctuation range of 720V±1.5%.

[0078] Fault interlock: Emergency shutdown when temperature exceeds the limit (>1300℃) or pressure changes suddenly (ΔP>50Pa).

[0079] like Figure 3 As shown, an energy-saving control method for magnetic levitation combustion and cooling fans in a double-chamber lime kiln is proposed. This method involves kiln chamber stage division and coordinated logic control.

[0080] Step S1: Calcination is carried out in one kiln chamber, and preheating and cooling are carried out in the other kiln chamber;

[0081] Step S2: Prepare for kiln chamber switching;

[0082] Step S3: Exchange the kiln chambers;

[0083] Step S4: Once the system is running stably, prepare for kiln switching and kiln exchange, repeating steps S1 to S4.

[0084] Step S1 specifically involves:

[0085] Calcination is carried out in kiln A, and the combustion fan speed is kept stable at a certain value (25,000 rpm, power consumption 285 kW); the air volume is dynamically adjusted according to the oxygen content sensor.

[0086] Kiln B is used for preheating and cooling, and the cooling fan speed is within a certain range (25,000 rpm, power consumption 270 kW).

[0087] The specific steps of step S2 are as follows:

[0088] Step S21: Close the fuel valve in kiln A, and the combustion blower begins to reduce its speed;

[0089] Step S22: Open the vent valve to release high-pressure gas;

[0090] In step S23, the combustion and cooling fans are simultaneously reduced to a certain speed (10,000 rpm) to generate electricity and feed back energy.

[0091] Step S3 specifically involves:

[0092] Kiln chamber A is switched to cooling chamber, and the cooling fan is accelerated to the corresponding rated speed (25,000 rpm);

[0093] Kiln chamber B is switched to calcination chamber, and the combustion fan is accelerated to the corresponding rated speed (25,000 rpm).

[0094] Step S4 specifically involves:

[0095] Step S41: Close the fuel valve in kiln B, and the combustion blower begins to reduce its speed;

[0096] Step S42: Open the vent valve to release the high-pressure gas;

[0097] Step S43: The combustion and cooling fans are simultaneously reduced to a certain speed (10,000 rpm) to generate electricity and feed back energy.

[0098] Step S44: Kiln chamber B is switched to cooling chamber, and the cooling fan is accelerated to the corresponding rated speed (25,000 rpm);

[0099] Step S45: Kiln chamber A is switched to calcination chamber, and the combustion blower is accelerated to the corresponding rated speed (25,000 rpm).

[0100] like Figure 4 As shown, the energy-saving equipment for magnetic levitation combustion and cooling fans in a double-chamber lime kiln includes:

[0101] The output end of the combustion-supporting magnetic levitation blower is connected to the input end of the first cylinder, the input end of the first temperature sensor, the input end of the first pressure sensor, and the input end of kiln chamber A, respectively.

[0102] The output end of the first cylinder is connected to the input end of the first vent muffler, and the output end of the first vent muffler is connected to the first vent outlet.

[0103] The output end of the cooling magnetic levitation blower is connected to the input end of the second temperature sensor, the input end of the second cylinder, the input end of the second pressure sensor, the input end of the third switching valve, and the input end of the fourth switching valve, respectively.

[0104] The output end of the second cylinder is connected to the input end of the second vent muffler, and the output end of the second vent muffler is connected to the second vent outlet.

[0105] The output of the third switching valve is connected to the input of kiln chamber A.

[0106] The output of the fourth switching valve is connected to the input of kiln chamber B;

[0107] Kiln chamber A is connected to kiln chamber B;

[0108] The output of the third temperature sensor is connected to kiln chamber A.

[0109] The output end of kiln A is connected to the input end of the first switching valve, the input end of the second switching valve, the input end of the oxygen content sensor, and the exhaust input end, respectively.

[0110] The output end of kiln B is connected to the input end of the second switching valve, the input end of the oxygen content sensor, and the exhaust input end, respectively.

[0111] Exhaust is carried out at the exhaust outlet.

[0112] Example 2

[0113] Based on Example 1

[0114] A double-chamber lime kiln uses the periodic switching of roles between chambers A and B (calcination) Preheating / cooling enables continuous production, with each cycle lasting 15 minutes. The combustion fan (300kW) and cooling fan (300kW) must work in tandem to ensure efficient heat transfer, stable pressure, and optimized energy consumption. The A / B kiln switching logic is described below with reference to Table 1:

[0115] Table 1

[0116]

[0117] Kiln chamber stage division and collaborative logic control, such as Figure 5 As shown

[0118] (1) Calcination stage (0-13 minutes)

[0119] Kiln chamber A: High-temperature calcination, with the combustion fan speed stabilized at 25,000 rpm and power consumption at 285 kW; the air volume is dynamically adjusted based on the oxygen content sensor.

[0120] B kiln chamber: preheating and cooling, cooling fan speed 25,000 rpm, power consumption 270 kW.

[0121] (2) Switching preparation phase (13-13 minutes 15 seconds)

[0122] When the A-chamber fuel valve is closed, the combustion fan begins to slow down; the vent valve is opened to release high-pressure gas; the combustion and cooling fans simultaneously slow down to 10,000 rpm, generating electricity and feeding back energy.

[0123] (3) Role reversal phase (13 minutes 15 seconds - 15 minutes)

[0124] The A chamber is switched to a cooling chamber, and the cooling fan is accelerated to 25,000 rpm; the B chamber is switched to a calcining chamber, and the combustion fan is accelerated to 25,000 rpm.

[0125] (4) Stable operation phase (starting from 15 minutes)

[0126] Entering the next operating cycle, the B chamber is calcined, and the A chamber is cooled.

[0127] The timing control logic is shown in Table 2 below:

[0128] Table 2

[0129]

[0130] The energy-saving benefits are shown in Table 3 below:

[0131] Table 3

[0132]

[0133] Energy-saving benefit analysis of this invention:

[0134] Net energy savings per switch: 2.56 kWh of power generation revenue per switch, 17.32 kWh of power saving per switch, totaling 19.88 kWh per switch.

[0135] Power generation revenue: 2.56 kWh / cycle

[0136] Pressure relief, frequency reduction, and stable cooling save power:

[0137]

[0138] Energy saving = 18.5 - 1.18 = 17.32 kWh

[0139] Net energy saving:

[0140] 2.56 (power generation) + 17.32 (power saving) = 19.88 kWh

[0141] Annual electricity savings: 524,832 kWh / year (calculated based on 80 switching times per day and 330 days per year).

[0142] 19.88 kWh / time × 80 times / day × 330 days = 524832 kWh

[0143] Economic benefits: Based on an industrial electricity price of 0.6 yuan / kWh, the annual electricity cost savings are approximately 315,000 yuan.

[0144] 524832 kWh × 0.6 yuan / kWh = 314899 yuan (approximately 315,000 yuan)

[0145] Emission reduction benefits: Reduces CO2 emissions by approximately 412 tons per year.

[0146] 524832 kWh × 0.785 kg / kWh = 412 tons

[0147] This invention achieves highly efficient and energy-saving operation of the combustion cooling process in a double-chamber lime kiln through innovative technologies such as dual-machine collaborative control, staged energy feedback, and lightweight rotor design. It achieves a net energy saving of 19.88 kWh per switch, an annual electricity saving of 524,800 kWh, and a comprehensive economic benefit of 315,000 yuan. Simultaneously, it significantly reduces CO2 emissions, providing an innovative energy-saving solution for the green and efficient operation of double-chamber lime kilns.

[0148] Example 3

[0149] Based on Example 1,

[0150] Currently, Roots blowers are mostly used in the combustion and cooling processes of double-chamber lime kilns. Because double-chamber lime kilns require frequent switching between the A and B chambers, venting is necessary to release pressure within the kiln during this process. Roots blowers, being positive displacement blowers, have heavy rotors with high inertia and slow speed adjustments. This is especially problematic when rapid pressure or flow adjustments are needed, leading to delayed responses and the necessity of venting compressed gas, wasting energy. In contrast, magnetic levitation centrifugal blowers use magnetic bearings, eliminating the need for rotor lubrication and significantly reducing weight. This allows for rapid speed adjustments to adapt to pressure changes during kiln chamber switching, reducing venting and saving energy.

[0151] The innovative dual-shaft, dual-impeller design constructs a two-stage axial force self-stabilizing system through fluid dynamic balance and structural strength optimization. It employs a mirror-symmetric, bidirectional suction impeller assembly, with each impeller equipped with 18 sets of backward-curved three-dimensional flow blades. During high-speed rotation, this creates a reverse vortex flow field, resulting in a periodic dynamic cancellation effect on the axial load. This design significantly reduces the pulsating axial force generated by traditional single-impeller structures, controlling the bearing load fluctuation within ±500N, and significantly extending the service life of the magnetic levitation bearing. Figure 6 As stated above.

[0152] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for energy-saving control of magnetic levitation combustion and cooling fan in a double-chamber lime kiln, characterized in that, include: The initial setting is the magnetic levitation combustion and cooling fan working mode for the double-chamber lime kiln; Depressurization of the magnetic levitation combustion and cooling fan in a double-chamber lime kiln is based on synchronous power generation mode. Based on the energy graded feedback strategy, dual-channel IGBT inverters and supercapacitor banks are used for energy feedback and off-grid power supply, respectively. The fan speed is adjusted based on a dynamic frequency conversion control strategy to achieve a cubic match between power and speed. Rapid response for switching of magnetic levitation combustion and cooling fans in a double-chamber lime kiln based on lightweight rotor rotational inertia; Safety protection is implemented during the switching process of a dual-chamber lime kiln based on a safety protection mechanism. Power generation control is based on rapid response to rotor speed reduction.

2. The energy-saving control method for magnetic levitation combustion and cooling fan in a double-chamber lime kiln according to claim 1, characterized in that, The initial setup for the magnetic levitation combustion and cooling fan operation mode of the dual-chamber lime kiln includes using kiln A for high-temperature calcination and kiln B for preheating and cooling. During high-temperature calcination in kiln A, the combustion fan speed is stabilized at 25,000 rpm with a power consumption of 285 kW, and the airflow is dynamically adjusted based on an oxygen content sensor. During preheating and cooling in kiln B, the cooling fan speed is 25,000 rpm with a power consumption of 270 kW, and the calcination phase lasts for 13 minutes. Simultaneously, during the switching preparation phase, the combustion fan speed is reduced by closing the fuel valve in kiln A; at the same time, the vent valve is opened to release high-pressure gas, thus depressurizing the combustion and cooling fans to a synchronized speed reduction to 10,000 rpm, generating electricity and feeding back energy.

3. The energy-saving control method for magnetic levitation combustion and cooling fan in a double-chamber lime kiln according to claim 2, characterized in that, The described method for depressurizing the magnetic levitation combustion and cooling fans in a dual-chamber lime kiln based on synchronous power generation includes the following: during the depressurization phase, the combustion and cooling fans synchronously switch to generator mode via a CAN bus, completing a speed reduction from 25,000 rpm to 10,000 rpm within 15 seconds. During this process, the total power generation energy is 9210 kJ, or 2.56 kWh / cycle. Converted to kilowatt-hours (kWh), this is expressed as: 9210 ÷ 3600 = 2.56 kWh / cycle, where the inertia J of the carbon fiber composite rotor is 1.6 kg·m. 2 , is represented as:

4. The energy-saving control method for magnetic levitation combustion and cooling fan in a double-chamber lime kiln according to claim 3, characterized in that, The energy-graded feedback strategy utilizes a dual-channel IGBT inverter and a supercapacitor bank for energy feedback and off-grid power supply. Specifically, based on the energy-graded feedback strategy, the dual-channel IGBT inverter converts 2.05 kWh / cycle of energy into 380V / 50Hz AC power to feed back to the grid, reducing the cost of purchased electricity. The remaining 0.51 kWh / cycle of energy is stored in a 100F supercapacitor bank for off-grid power supply to cool the system, reducing dependence on the grid during switching. The supercapacitor bank operates at 750V.

5. The energy-saving control method for magnetic levitation combustion and cooling fan in a double-chamber lime kiln according to claim 4, characterized in that, The dynamic frequency conversion control strategy for adjusting fan speed to achieve a cubic match between power and speed includes adjusting fan speed in real time according to the kiln state during pressure relief, thus significantly reducing energy consumption. Specifically, during the pressure relief phase, the total power consumption of the two fans decreased from 555kW to 35.52kW, achieving an energy saving rate of 93.6%. The power consumption figures are as follows: Where: P 助燃 P represents the actual power consumption of the combustion fan at its lowest speed. 额1 P represents the actual power consumption of the combustion fan at its rated speed. 冷却 P represents the actual power consumption of the cooling fan at its lowest speed. 额2 n is the actual power consumption of the cooling fan at its rated speed; n1 is the minimum speed of the combustion fan after speed reduction; n 额1 n1 is the rated speed of the combustion fan; n2 is the minimum speed of the cooling fan after speed reduction; n 额2 This is the rated speed of the cooling fan.

6. The energy-saving control method for magnetic levitation combustion and cooling fan in a double-chamber lime kiln according to claim 5, characterized in that, The rapid response of the magnetic levitation combustion and cooling fan switching of the dual-chamber lime kiln based on the rotational inertia of the lightweight rotor includes switching chamber A to the cooling chamber and accelerating the cooling fan to 25,000 rpm; switching chamber B to the calcination chamber and accelerating the combustion fan to 25,000 rpm. The entire process lasts from 13 minutes and 15 seconds to 15 minutes. From 15 minutes, a stable operation phase begins, and the next operating cycle begins, i.e., calcination in chamber B, cooling in chamber A, with the combustion fan operating at 10k to 25k rpm and the cooling fan operating at 10k to 25k rpm.

7. The energy-saving control method for magnetic levitation combustion and cooling fan in a double-chamber lime kiln according to claim 6, characterized in that, The rotor used has a carbon fiber composite rotor with a moment of inertia of J = 1.6 kg·m. 2 It meets the requirement of reducing speed from 25,000 rpm to 10,000 rpm and increasing speed within 15 seconds.

8. The energy-saving control method for magnetic levitation combustion and cooling fan in a double-chamber lime kiln according to claim 7, characterized in that, Safety protection mechanisms are implemented during the switching process of the dual-chamber lime kiln. These mechanisms include real-time monitoring of flow and pressure curves to trigger frequency adjustments to suppress surge, thereby achieving surge suppression; maintaining voltage stability within the allowable fluctuation range using a bidirectional DC / DC module to achieve bus voltage stabilization; and emergency shutdown in case of temperature exceeding limits or sudden pressure changes to achieve fault interlocking.

9. A magnetic levitation combustion and cooling fan energy-saving control system for a double-chamber lime kiln according to any one of claims 1-8, characterized in that, include: The double-chamber lime kiln, lightweight rotor bearing system, and magnetic levitation blower unit are connected to the double-chamber lime kiln to form a magnetic levitation combustion and cooling fan for the double-chamber lime kiln. The output end of the magnetic levitation combustion and cooling fan of the double-chamber lime kiln is connected to the input end of the lightweight rotor bearing system. The lightweight rotor bearing system includes a carbon fiber composite rotor and a five-degree-of-freedom magnetic levitation bearing. The carbon fiber composite rotor includes a main shaft, a radial rotor core assembly, magnets, a carbon fiber sheath, a thrust disk, and an axial sensor detection disk. The main shaft is connected to the radial rotor core assembly, magnets, carbon fiber sheath, thrust disk, and axial sensor detection disk. The carbon fiber sheath is connected to the magnets. The thrust disk is connected to the axial sensor detection disk.

10. The energy-saving control system for magnetic levitation combustion and cooling fan in a double-chamber lime kiln according to claim 9, characterized in that, The output end of the combustion-supporting magnetic levitation blower is connected to the input end of the first cylinder, the input end of the first temperature sensor, the input end of the first pressure sensor, and the input end of kiln chamber A, respectively. The output end of the first cylinder is connected to the input end of the first venting silencer, and the output end of the first venting silencer is connected to the first vent outlet. The output end of the cooling magnetic levitation blower is connected to the input ends of the second temperature sensor, the second cylinder, the second pressure sensor, the third switching valve, and the fourth switching valve, respectively. The output end of the second cylinder is connected to the input end of the second venting silencer, and the output end of the second venting silencer is connected to the second vent outlet. The output end of the third switching valve is connected to the input end of kiln chamber A, and the output end of the fourth switching valve is connected to the input end of kiln chamber B.

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