Multi-element accurate matching low-temperature brimstone furnace control system

Abstract

The utility model discloses a multi-element accurate proportioning low-temperature brimstone furnace control system, which mainly comprises a central controller, and a data acquisition unit, a fan driving unit, a molten sulfur control unit, a metering pump control unit, an atomization control unit, an ignition control unit, a hearth positive and negative pressure protection unit and a brimstone furnace high and low temperature protection unit which are connected with and controlled by the central controller. The sulfur combustion furnace system automatically and accurately distributes air and sulfur according to the squeezing amount or the flow, the stoving intensity and the like, and the problems that due to the fact that an existing sulfur combustion furnace system is inaccurate in air distribution and sulfur distribution, combustion is insufficient, sublimed sulfur is much, and technological indexes are unstable are solved.

Description

Technical Field

[0001] This utility model belongs to the field of sulfur combustion furnace control technology, and in particular relates to a multi-dimensional precise proportioning low-temperature sulfur combustion furnace control system. Background Technology

[0002] A sulfur combustion furnace, which uses sulfur as a raw material to produce sulfur dioxide, is a crucial piece of equipment in sugar factories. The sulfur combustion furnace operates in a high-temperature, slightly negative-pressure environment, therefore its materials and systems are highly demanding. Not only must the system operate normally, but it must also possess a certain level of sealing to prevent the leakage of high-temperature gases from inside the furnace. Furthermore, the design and operation of sulfur combustion furnaces present several technical challenges.

[0003] <1> Traditional sulfur-burning furnaces use manual ignition, which has a low success rate and poses significant safety hazards. Operators heat an object to a high temperature outside the furnace and then manually insert it into the furnace to spray sulfur for ignition. However, because sulfur dust is flammable and explosive, this operation can easily lead to combustion and explosion. When the furnace is under positive pressure, flames will spray out from the ignition port, causing burns or sulfur gas leaks.

[0004] <2> An uncoordinated air distribution ratio can easily lead to under-combustion or over-combustion, producing sublimated sulfur. Furthermore, equipment malfunctions, such as the inability to activate interlocks, can also affect the normal operation of the equipment. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a multi-dimensional precision proportioning low-temperature sulfur combustion furnace control system that is structurally reasonable, effective, safe and reliable.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] The multi-dimensional precision proportioning low-temperature sulfur combustion furnace control system mainly consists of a central controller and its connected and controlled data acquisition unit, fan drive unit, sulfur melting control unit, metering pump control unit, atomization control unit, ignition control unit, and positive and negative pressure protection unit.

[0008] The data acquisition unit connects to and acquires data from temperature sensors, pressure sensors, level sensors, flow meters, equipment status modules, position sensors, and vision cameras.

[0009] The central controller mainly includes a manual module, a one-button stop module, a pressing capacity setting module, a flow tracking module, a spray gun low temperature protection module, a furnace high and low temperature protection module, a furnace negative pressure protection module, an atomizing device low temperature protection module, an equipment fault protection module, a visual inspection module, and a remote monitoring module.

[0010] The central controller is also connected to the host computer monitoring system, cloud platform, and APP monitoring system.

[0011] The blower drive unit connects to and controls the Roots blower; the sulfur melting control unit connects to and controls the L-shaped heating rod; the metering pump control unit connects to and controls the submersible gear metering pump; the atomization control unit connects to and controls the air heater, atomizing valve, and spray gun; the ignition control unit connects to and controls the heater and ignition telescopic device; and the positive and negative pressure protection unit connects to and controls the bypass valve, exhaust fan, and vent valve.

[0012] To address the current problems in sulfur combustion furnaces and their operation, the inventors have developed a multi-dimensional, precise proportioning low-temperature sulfur combustion furnace control method. First, sulfur is dissolved into liquid sulfur and kept at a constant temperature. The sulfur spray gun and atomizer are also heated and kept at a constant temperature using compressed air. Next, the sulfur combustion furnace is depressurized, and after depressurization, a blower is activated to supply air to the furnace chamber. Then, the heating rod in the igniter is started to raise the temperature. Once the preset temperature is reached, the liquid sulfur is sprayed into the furnace chamber through the sulfur spray gun for ignition. After successful ignition, atomization is activated, and the sulfur combustion furnace enters normal operation. This method solves the problems of ignition safety and ignition success rate in sulfur combustion furnaces. Based on this, a corresponding sulfur combustion furnace control system was developed, mainly consisting of a central controller and its connected and controlled data acquisition unit, blower drive unit, sulfur melting control unit, metering pump control unit, atomization control unit, ignition control unit, and positive and negative pressure protection unit. This system solves the problems of air distribution ratio and equipment failure interlocking in sulfur combustion furnaces, as well as ignition safety and ignition success rate.

[0013] Compared with the prior art, the advantages of the sulfur combustion furnace control system of this utility model are as follows:

[0014] 1. High degree of automation, capable of frequency conversion regulation, and easy to operate and use.

[0015] 2. Ignition operation is safer and the ignition success rate is greatly improved.

[0016] 3. The ratio of sulfur injection volume to air volume is appropriate, so that the sulfur can be fully burned and no sublimated sulfur is produced.

[0017] 4. Safe and reliable, with diverse control methods and stable working performance. Attached Figure Description

[0018] Figure 1 This is a basic structural diagram of the low-temperature sulfur combustion furnace operating system. In the diagram: 1: Sulfur combustion furnace; 2: Roots blower #1 and outlet valve; 3: Roots blower #2 and outlet valve; 4: Bypass valve; 5: Sulfur melting box; 6: Pumping box; 7: Ignition device #1; 8: Ignition device #2; 9: Air heater #1 and atomizing valve; 10: Air heater #2 and atomizing valve; 11: Air heater #3 and atomizing valve; 12: Air heater #4 and atomizing valve; 13: Sulfur pumps #1 and #2; 14: Sulfur pumps #3 and #4; 15: Exhaust fan and exhaust valve.

[0019] Figure 2This is a process flow diagram of the multi-dimensional precise proportioning low-temperature sulfur combustion furnace control method in this utility model.

[0020] Figure 3 This is a schematic diagram of the system operation flow corresponding to the multi-dimensional precise proportioning low-temperature sulfur combustion furnace control method in this utility model.

[0021] Figure 4 This is a schematic diagram of the structure of the multi-dimensional precision proportioning low-temperature sulfur combustion furnace control system of this utility model. Detailed Implementation

[0022] I. Existing Technology and Problems

[0023] Figure 1 It is a low-temperature sulfur combustion furnace operating system, which mainly consists of a sulfur combustion furnace, a Roots blower, a sulfur melting box, a pumping box, a sulfur injection motor and its submersible pump, an igniter (including a telescopic device and a heating rod), an air heater, an atomizing valve, a cooler, an exhaust fan, and an exhaust valve. The igniter includes a telescopic device and a heating rod; the telescopic device extends or retracts the igniter rod via an electric or pneumatic actuator.

[0024] Currently, the operation of low-temperature sulfur combustion furnace systems mainly relies on operators' skilled experience based on actual production conditions, failing to achieve standardized and automated intelligent control. Consequently, there are risks such as low ignition success rate and high safety hazards. In addition, uncoordinated air distribution causes combustion imbalance, leading to sulfur sublimation and resulting in high equipment failure rate.

[0025] II. Control Strategies and Implementation Methods

[0026] The performance of a sulfur combustion furnace depends on reliable ignition, which is the successful combustion of liquid sulfur injected into the furnace after it has been molten. Successful ignition depends on factors such as the temperature of the liquid sulfur, the temperature of the sulfur lance, the temperature of the igniter, and the oxygen content within the furnace. The temperature of the liquid sulfur depends on the heating temperature within the rated heating time; the temperature of the sulfur lance depends on the heat of the compressed gas provided within the rated heating time; the temperature of the igniter depends on the heating temperature of the heating rods within the rated heating time; and the oxygen content within the furnace depends on the air volume provided by the Roots blower within the rated time. These factors can be controlled by accurately regulating the operating status of the heating rods, air heater, Roots blower, and jet motor.

[0027] Therefore, such as Figure 2As shown, the multi-dimensional precise proportioning low-temperature sulfur combustion furnace control method involves the following steps: First, sulfur is dissolved into liquid sulfur and kept at a constant temperature. The sulfur spray gun and atomizing compressed air are also heated and kept at a constant temperature. Next, the heating rod in the igniter is activated to raise the temperature, while simultaneously opening the vent valve, vent fan, and bypass valve to depressurize the sulfur combustion furnace. After depressurization, the Roots blower and outlet valve are activated to supply air to the furnace. Then, once the heating rod reaches the preset temperature, it is moved to the ignition position, and the sulfur metering pump is activated to inject liquid sulfur into the furnace through the sulfur spray gun for ignition. After successful ignition, the atomizing valve is opened, and the vent fan, vent valve, and bypass valve are closed, allowing the sulfur combustion furnace to enter normal operation. The liquid sulfur holding temperature is 100-250℃, the sulfur spray gun and atomizing compressed air holding temperatures are 90-160℃ and 130-180℃ respectively, and the preset igniter heating temperature is 200-800℃. Successful ignition is achieved when the temperature inside the furnace exceeds the set ignition temperature and the temperature rise within the rated ignition time exceeds the set value. The temperature parameters vary from sugar factory to sugar factory. Generally, the ignition temperature is 40-500℃, the rated ignition time is 10-800 seconds, and the set temperature rise is 0-200℃.

[0028] In current sugar mills, there are two performance indicators for sulfur combustion furnaces: one is whether they can maintain continuous combustion without flameout, and the other is whether the sulfur dioxide emitted, after reacting with sugarcane juice, achieves the required sulfur fumigation intensity. Continuous combustion and the measured sulfur fumigation intensity mainly depend on the sulfur injection rate of the sulfur melting module, the air volume provided by the Roots blower, and the real-time sugarcane juice flow rate (either set or fed back by a flow meter). These three factors must be matched; otherwise, under-combustion or over-combustion will occur. Users may have varying requirements for the sulfur fumigation intensity, which can be achieved by adjusting the operating status of the Roots blower and the sulfur injection motor.

[0029] Therefore, based on the sugar mill's daily crushing volume or the signal from the mixed juice flow meter, the sulfur-to-cane ratio, the required sulfur fumigation intensity, and the absorption rate, the required amount of sulfur is calculated using formulas. Then, the range of the metering pump is used to calculate and control the speed of the metering pump, thereby regulating the sulfur input. Next, the required air volume is calculated by combining the required amount of sulfur with the chemical equation for the combustion of sulfur and oxygen and the sulfur dioxide concentration. Finally, the air volume is regulated by combining the range of the blower and controlling the speed of the blower.

[0030] III. Multi-dimensional Precision Proportioning Low-Temperature Sulfur Combustion Furnace Control System and its Operation

[0031] 3.1 System Structure

[0032] like Figure 4As shown, the multi-dimensional precision proportioning low-temperature sulfur combustion furnace control system of this utility model mainly consists of a central controller and its connected and controlled data acquisition unit, fan drive unit, sulfur melting control unit, metering pump control unit, atomization control unit, ignition control unit, and positive and negative pressure protection unit. In addition, the central controller is also connected to a host computer monitoring system, a cloud platform, and an APP monitoring system.

[0033] The data acquisition unit connects to and acquires data from temperature sensors, pressure sensors, level sensors, flow meters, equipment status modules, position sensors, and vision cameras.

[0034] The blower drive unit connects to and controls the Roots blower; the sulfur melting control unit connects to and controls the L-shaped heating rod; the metering pump control unit connects to and controls the submersible gear metering pump; the atomization control unit connects to and controls the air heater, atomizing valve, and spray gun; the ignition control unit connects to and controls the heating rod and ignition telescopic device; and the positive and negative pressure protection unit connects to and controls the bypass valve, exhaust fan, and vent valve.

[0035] The central controller mainly includes a manual module, a one-button stop module, a pressing capacity setting module, a flow tracking module, a spray gun low temperature protection module, a furnace high and low temperature protection module, a furnace positive and negative pressure protection module, an atomizing device low temperature protection module, an equipment fault protection module, a visual inspection module, and a remote monitoring module.

[0036] Table 1. List of Component Sources for the Multidimensional Precision Proportioning Low-Temperature Sulfur Combustion Furnace Control System

[0037]

[0038]

[0039] 3.2 System Functions

[0040] <1> Central controller

[0041] The central controller accepts commands from the input device and issues commands to each controlled unit / device, thereby achieving control over each part of the system. The central controller has manual and / or automatic modes; the automatic mode includes a pressing rate setting mode and a flow tracking mode; among which,

[0042] For ease of inspection and maintenance, a manual mode is provided. In manual mode, each working unit can be operated independently, meaning that the speed of the submersible gear metering pump and the blower can be manually controlled, and various valves and blowers can be manually opened via the human-machine interface.

[0043] The crushing rate setting mode (implemented by the crushing rate setting module) calculates the required sulfur amount based on the sugar mill's daily crushing rate, sulfur-to-cane ratio, required sulfur fumigation intensity, and absorption rate using formulas. Then, based on the submersible gear metering pump's range and the required sulfur amount, the pump speed is calculated and output to the metering pump control unit for regulation. Next, by calculating the required sulfur amount and combining it with the chemical equation for sulfur-oxygen combustion and sulfur dioxide concentration, the required airflow is calculated. Finally, based on the blower's range, the blower speed is calculated and output to the blower drive unit for regulation. The relevant calculation formulas are as follows:

[0044]

[0045]

[0046]

[0047]

[0048] The flow tracking mode (implemented by the flow tracking module) calculates the required amount of sulfur based on the signal from the mixed juice flow meter, the sulfur-to-succulent ratio, the required sulfur fumigation intensity, and the absorption rate. Then, based on the range of the submersible gear metering pump and the required amount of sulfur, the pump speed is calculated and output to the metering pump control unit for regulation. Next, by calculating the required amount of sulfur, combining the chemical equation for the combustion of sulfur and oxygen, and the sulfur dioxide concentration, the required air volume is calculated. Finally, based on the fan's range, the fan speed is calculated and output to the fan drive unit for regulation.

[0049] <2> The visual inspection module uses a visual camera to determine whether the sulfur combustion furnace is ignited and to observe the color of the flame to judge the combustion status of sulfur.

[0050] <3> The atomization control unit controls the air heater of the atomization device, keeping the compressed air at around 180 degrees Celsius. The heated compressed air is then sprayed out from the nozzle of the spray gun after being fully mixed with liquid sulfur, allowing the sulfur to atomize and come into full contact with oxygen for combustion.

[0051] <4> The system is equipped with comprehensive protection units, including a low-temperature protection module for the spray gun, a high and low temperature protection module for the furnace, a positive and negative pressure protection module for the furnace, a low-temperature protection module for the atomizing device, and an equipment fault protection module. Among these,

[0052] The spray gun low temperature protection module is designed to automatically activate the backup spray gun and trigger an alarm when the spray gun temperature drops below the protection set value during system operation.

[0053] The furnace high and low temperature protection module automatically shuts down the system (following the automatic shutdown procedure) and alarms when the furnace temperature falls below the set value during system operation. There are two scenarios for excessively low temperature: one is ignition failure. After a certain period of operation, the central controller detects that the temperature sensor indicates a low temperature and immediately alarms, while the sulfur injection motor and Roots blower stop. The other scenario is that during operation, the flame in the furnace goes out. The central controller detects that the temperature sensor indicates a low temperature and immediately alarms, while the Roots blower and sulfur injection motor stop, and the fiberglass blower starts.

[0054] When the furnace temperature exceeds the set value, the system will automatically shut down (following the automatic shutdown procedure) and sound an alarm to prevent the boiler from drying out due to lack of cooling water. If the temperature sensor in the furnace water jacket reports an excessively high temperature, an alarm will sound immediately, and the Roots blower and sulfur injection motor will stop, while the FRP blower will start.

[0055] The furnace positive and negative pressure protection module automatically opens the bypass valve and alarms when the furnace negative pressure is less than the set value during system operation; and automatically opens the exhaust fan and exhaust valve and alarms when the furnace positive pressure is greater than the set value.

[0056] The low-temperature protection module for the atomizing device is designed to automatically activate the backup atomizing device and trigger an alarm if the compressed air temperature of the atomizing device falls below a set value during system operation.

[0057] The equipment fault protection module is designed to automatically activate backup equipment and trigger an alarm if the fan, fan outlet valve, metering pump, or atomizing valve malfunctions during system operation.

[0058] <5> Ignition control unit

[0059] The central controller outputs commands to drive the ignition control unit to control the heating of the heating rod. When the heating rod reaches the set temperature, it automatically stops heating, and when the temperature is lower than the set temperature, it automatically starts heating.

[0060] <6> Sulfur melting control unit

[0061] The sulfur melting chamber uses electric heating elements to melt solid sulfur into liquid sulfur and maintain the temperature within the range of 110℃ to 250℃. The central controller controls the on / off state of the electric heating elements through the sulfur melting control unit based on the temperature feedback from the temperature sensor, thereby controlling the sulfur melting temperature.

[0062] <7> The manual module can drive any working unit independently, including Roots blowers, fiberglass blowers, sulfur injection motors, and electronic valves.

[0063] <8> The remote monitoring module can exchange data with host computer monitoring systems, cloud platforms, and APP monitoring systems.

[0064] <9> The one-button shutdown module is connected to the sulfur injection motor, Roots blower, FRP blower, and corresponding valves. It is a safety auxiliary function module for the sulfur combustion furnace. Its workflow is as follows: at any time during the sulfur combustion furnace's operation, when the customer presses the shutdown button, the one-button shutdown module will detect whether the sulfur injection motor has stopped. If the sulfur injection motor has stopped, it will activate the FRP blower and its corresponding valves, then shut down the Roots blower and its corresponding valves after a delay, and simultaneously close the corresponding valve of the air heater. Upon detecting a feedback signal, it will further delay stopping the FRP blower and closing its corresponding valves.

[0065] <10> Sensors and detection devices

[0066] Temperature sensor:

[0067] Furnace temperature monitoring: Real-time feedback of the core temperature of the sulfur combustion furnace to the central controller, participating in the furnace high and low temperature protection logic. Spray gun temperature monitoring: Detects the operating temperature of the spray gun and triggers the spray gun low temperature protection mechanism.

[0068] Atomizing device monitoring: Detects compressed air heating temperature (set value 130℃-180℃) and triggers low-temperature protection of the atomizing device.

[0069] Temperature control of the sulfur melting box: Dual redundant sensors monitor the temperature of liquid sulfur (100-180℃), and the electric heating element is controlled in a closed loop.

[0070] Cooling water temperature monitoring: Prevents dry burning accidents and triggers emergency shutdown when the temperature exceeds the limit.

[0071] Pressure sensor:

[0072] Furnace pressure monitoring: Real-time detection of positive / negative pressure status, combined with variable frequency fan to achieve dynamic balance control of ±5Pa.

[0073] Compressed air pressure test: Ensure the atomizing device's operating pressure is stable within the range of 0.4-0.6 MPa.

[0074] Flow meter:

[0075] Mixed juice electromagnetic flow meter: 4-20mA signal output, accuracy ±0.5%, used in flow tracking mode calculation.

[0076] Position sensor:

[0077] Valve opening feedback: Magnetostrictive sensors detect the real-time position of pneumatic / electric valves.

[0078] Visual camera:

[0079] Dual-spectral imaging system: visible light monitoring of flame morphology.

[0080] <11> Core control unit

[0081] Fan drive unit:

[0082] Integrated frequency converter cluster: controls the coordinated operation of Roots blowers (main process air) and FRP exhaust fans.

[0083] Dynamic airflow adjustment: Automatically corrects PID parameters based on SO2 concentration feedback, with a response time of <200ms.

[0084] Metering pump control unit:

[0085] Servo drive system: controls the speed of the submersible gear pump

[0086] Positive and negative pressure protection unit:

[0087] Intelligent bypass control: Automatically selects the on / off state of the bypass valve and exhaust fan based on the pressure differential gradient (hardware level) + PLC logic protection (software level) for dual protection.

[0088] <12> Device Status Module

[0089] Current fingerprint analysis: Identifies abnormal conditions such as stalled rotor and overload by analyzing the harmonic characteristics of the motor's operating current.

[0090] Communication status diagnostics: PROFINET network topology monitoring to locate communication faulty nodes.

[0091] <13> Safety Redundancy Design

[0092] Three-out-of-two voting system: Critical protection signals (such as furnace over-temperature) employ triple redundant sensors + logic voting independent safety relays; emergency stop circuit is physically isolated from the PLC system, achieving SIL3 safety level.

[0093] Uninterrupted power supply: Key sensors and control units are equipped with a 72-hour UPS + supercapacitor dual backup power supply.

[0094] This configuration enables digital closed-loop control of the entire process, constructing a complete monitoring and control network through 146 I / O points (including 38 AI, 52 AO, and 56 DI / DO), meeting the continuous production needs of sugar factories, achieving a system availability of 99.95%, and improving sulfur combustion efficiency to 92.3%.

[0095] 3.3 System Operation (e.g.) Figure 2 and Figure 3 )

[0096] <1> Solid sulfur is poured into the sulfur melting tank and pumping tank. An electric heating rod is used to melt the sulfur into a liquid state, maintaining the temperature between 100℃ and 250℃ to prevent the sulfur from clogging the spray nozzles if the temperature is too low. The air heater is then turned on to heat the compressed air, maintaining its temperature between 130℃ and 180℃. The spray nozzle temperature is maintained between 90℃ and 160℃, as a low spray nozzle temperature can easily cause sulfur to clog the spray nozzle pipes.

[0097] <2> Open the bypass valve, vent valve and vent fan (fiberglass fan) to relieve pressure. If the negative pressure in the furnace is too high (the furnace pressure is detected by the pressure transmitter), the Roots blower will not be able to start.

[0098] <3> After depressurization is completed, the Roots blower and outlet valve are turned on to supply air into the furnace to help the sulfur ignite and burn.

[0099] <4> Start the heating rod in the igniter and heat it to 200℃-800℃. Then, activate the igniter telescopic device to extend the igniter rod into the furnace.

[0100] <5> After the ignition rod is inserted into the furnace, the sulfur injection motor is turned on, and the submersible sulfur pump starts, injecting liquid sulfur into the furnace through a sulfur spray gun for ignition. A clear flame can be observed inside the furnace through the sight glass. Ignition is considered successful if the furnace temperature exceeds the set ignition temperature and the furnace temperature rises above the set value within the rated ignition time. The temperature parameters vary from sugar factory to sugar factory, but generally the ignition temperature is 40℃-500℃, the rated ignition time is 10 seconds-800 seconds, and the set temperature rise is 0-200℃.

[0101] <6> After successful ignition, the igniter retracts, the atomizing valve opens, and the exhaust fan, exhaust valve, and bypass valve are shut off, allowing the system to enter normal operation. If the atomizing valve opens prematurely, the flame may be extinguished or ignition may fail.

Claims

1. A multi-dimensional precision proportioning low-temperature sulfur combustion furnace control system, characterized in that... It mainly consists of a central controller and its connected and controlled data acquisition unit, fan drive unit, sulfur melting control unit, metering pump control unit, atomization control unit, ignition control unit, and positive and negative pressure protection unit; the fan drive unit is connected to and controls a Roots blower; the sulfur melting control unit is connected to and controls an L-shaped heating rod; the metering pump control unit is connected to and controls a submersible gear metering pump; the atomization control unit is connected to and controls an air heater, atomizing valve, and spray gun; the ignition control unit is connected to and controls a heating rod and an igniter telescopic device; and the positive and negative pressure protection unit is connected to and controls a bypass valve, an exhaust fan, and an air vent valve.

2. The sulfur combustion furnace control system according to claim 1, characterized in that: The data acquisition unit is connected to and acquires data from temperature sensors, pressure sensors, level sensors, flow meters, equipment status modules, position sensors, and vision cameras.

3. The sulfur combustion furnace control system according to claim 1, characterized in that: The central controller mainly includes a manual module, a one-button stop module, a pressing capacity setting module, a flow tracking module, a spray gun low temperature protection module, a furnace high and low temperature protection module, a furnace positive and negative pressure protection module, an atomizing device low temperature protection module, an equipment fault protection module, a visual inspection module, and a remote monitoring module.

4. The sulfur combustion furnace control system according to claim 3, characterized in that: The central controller is also connected to a host computer monitoring system, a cloud platform, and an APP monitoring system.

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