A feeding system and a feeding control method of a molten salt chlorination furnace

Abstract

The present application relates to molten salt chlorination furnace feeding technical field, specifically disclose a kind of feeding control method of molten salt chlorination furnace, it is applicable to the feeding control of 160t / d and above capacity molten salt chlorination furnace.The feeding control method includes the following steps: ratio setting: according to process requirement, set the target ratio of each raw material, each raw material is according to the target ratio Synchronous feeding;Multi-component mixing: each raw material is transported to mixing device according to the ratio and is mixed, and mixed material is transported into molten salt chlorination furnace;Component dynamic regulation: real-time acquisition molten salt component detection signal in molten salt chlorination furnace, calculate the deviation between current component and target component, according to deviation, modify and adjust feeding rate.The present application realizes raw material accurate proportioning, efficient mixing and real-time adaptation of feeding rate by multi-unit collaborative design and component dynamic regulation mechanism, guarantees the stable and efficient operation of large-scale molten salt chlorination furnace.

Description

Technical Field

[0001] This invention belongs to the field of molten salt chlorination furnace feeding technology, specifically relating to a feeding system and feeding control method for a molten salt chlorination furnace. Background Technology

[0002] With the large-scale development of the titanium industry, molten salt chlorination furnaces are gradually being upgraded to larger sizes, with large-scale equipment with a capacity of 160t / d and above becoming the industry mainstream. However, in the process of scaling up, the accuracy and stability of the feeding system have become key bottlenecks restricting production efficiency. The existing feeding methods for molten salt chlorination furnaces generally suffer from the following technical defects: First, the accuracy of raw material proportioning is insufficient. The mixing of titanium slag, petroleum coke, and sodium chloride relies heavily on empirical proportioning and lacks precise metering devices, resulting in excessive fluctuations in the composition of the molten salt system, which directly affects the chlorination reaction efficiency and the quality of titanium tetrachloride products. Second, the uniformity of material mixing is poor. Traditional single-shaft stirring or direct feeding methods cannot achieve sufficient mixing of multi-component raw materials, which can easily lead to local over-excess of reducing agent or insufficient molten salt medium, causing problems such as local overheating and reduced chlorine utilization. Third, the control of the feeding rate is lagging. Existing systems mostly use a fixed feeding rate and cannot be dynamically adjusted in real time according to the composition of the molten salt in the furnace. When the TiO2 or C content in the molten salt fluctuates abnormally, it can easily lead to reaction imbalance and even cause equipment safety hazards. Fourth, the adaptability is poor. Existing feeding systems are mostly designed for small and medium-capacity furnaces and cannot meet the continuous and high-flow-rate feeding requirements of large molten salt chlorination furnaces of 160t / d and above.

[0003] In existing molten salt chlorination furnace feeding technologies, CN203668018U discloses a chlorination furnace feeding device that uses loss-in-weight scales corresponding to each hopper for material metering and employs a first screw conveyor to premix various materials before feeding them into the chlorination furnace. This scheme improves feeding accuracy and mixing uniformity to some extent, but the mixing only uses a single screw conveyor, resulting in limited uniformity. CN224151431U proposes a feeding device for molten salt chlorination furnaces that uses a weighing hopper with a weighing module and a switching module, along with a controller, to achieve automated switching and continuous feeding of multiple feeding units. This improves automation control, but it still does not solve the problem of linkage control between the feeding rate and the composition of the molten salt in the furnace.

[0004] CN121115910A proposes a method for dynamic control of molten salt composition in molten salt chlorination furnaces, which involves periodically sampling and detecting the concentrations of TiO2 and C in the molten salt, calculating the concentration deviation, and adjusting the feeding rates of titanium slag and petroleum coke accordingly. This achieves dynamic adjustment of the proportions based on composition feedback. However, this method relies on periodic sampling and detection, limiting its timeliness.

[0005] Furthermore, the scaling up of molten salt chlorination furnaces significantly alters the material balance and melt kinetics environment, placing higher demands on the continuous stability, high-flow-rate delivery capacity, and adaptability of the feeding system. Existing feeding systems are mostly designed for small- to medium-capacity furnaces, exhibiting significant shortcomings in adaptability to large-scale chlorination furnaces of 160 t / d and above. While existing molten salt chlorination furnace feeding technologies have made progress in some areas such as metering and control algorithms, they generally suffer from low proportioning accuracy, insufficient mixing uniformity, lag in control, disconnect between component feedback control and the feeding execution system, and poor adaptability to large-scale applications.

[0006] Therefore, there is an urgent need to develop a feeding system and method with precise proportioning, efficient mixing, and adaptive component control to meet the production needs of large molten salt chlorination furnaces and improve feeding stability and reaction safety. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a feeding system and feeding control method for a molten salt chlorination furnace. Through multi-unit collaborative design and dynamic component regulation mechanism, it achieves precise raw material proportioning, efficient mixing, and real-time adaptation of feeding rate, ensuring the stable and efficient operation of large-scale molten salt chlorination furnaces.

[0008] To solve at least one of the above-mentioned technical problems, the present invention adopts the following technical solution: According to one aspect of the present invention, a feeding control method for a molten salt chlorination furnace is provided, applicable to the feeding control of molten salt chlorination furnaces with a capacity of 160 t / d and above. The feeding control method includes the following steps: Proportion setting: setting a target proportion for each raw material according to process requirements, and feeding each raw material synchronously according to the target proportion; Multi-component mixing: conveying each raw material fed according to the proportion to a mixing device for mixing, and then conveying the mixture to the molten salt chlorination furnace; Dynamic component adjustment: acquiring the molten salt component detection signal in the molten salt chlorination furnace in real time, and calculating the deviation value between the current component and the target component. Wherein, when the deviation value exceeds a preset threshold, independently calculating the target correction amount for the required feeding rate of each raw material based on the deviation value; adjusting the feeding rate of the corresponding raw material according to the target correction amount, so that the actual feeding rate of each raw material deviates from the target proportion to compensate for the deviation of the molten salt component in the furnace; until the molten salt component in the furnace returns to the set range, the feeding rate of each raw material returns to the target proportion.

[0009] According to one embodiment of the present invention, the molten salt composition obtained in real time includes at least TiO2 content and C content.

[0010] According to one embodiment of the present invention, the raw materials include titanium slag, petroleum coke and sodium chloride. When the TiO2 content or C content is higher than the upper limit of the set value, the feeding rate of titanium slag or petroleum coke is reduced respectively; when the TiO2 content or C content is lower than the lower limit of the set value, the feeding rate of titanium slag or petroleum coke is increased respectively.

[0011] According to one embodiment of the present invention, in the component dynamic control step, at least one of the furnace temperature signal, pressure signal and chlorine flow signal is acquired, and the target correction amount is calculated in combination.

[0012] According to one embodiment of the present invention, the feeding control method further includes a safety interlocking step: real-time monitoring of the feeding resistance of the conveying unit, and when the feeding resistance exceeds a set threshold, activating the anti-bridging device of the corresponding raw material silo; and / or, real-time monitoring of the material level in the buffer container for temporarily storing the mixed material, and increasing the feeding rate and / or mixing rate when the material level is below the lower limit, and decreasing the feeding rate and / or mixing rate when the material level is above the upper limit.

[0013] According to another aspect of the present invention, a feeding system for a molten salt chlorination furnace is provided, applicable to molten salt chlorination furnaces with a capacity of 160 t / d and above, and executing the feeding control method described in any of the above embodiments. The system includes: a raw material supply unit, including multiple independent raw material bins; a metering and mixing unit, disposed downstream of the raw material supply unit, including metering devices connected to the outlets of each raw material bin and mixing devices disposed downstream of the metering devices; a conveying unit, disposed downstream of the metering and mixing unit and connected to the feed inlet of the molten salt chlorination furnace; and a control unit, signal-connected to the metering devices, the conveying unit, and the component detection device in the molten salt chlorination furnace, and performing dynamic component control based on the received signals.

[0014] According to one embodiment of the present invention, the control unit is configured to receive the real-time feed rate signal of the metering device and the real-time detection signal of the molten salt composition, generate independent adjustment instructions for the feed rate of each raw material, and control the metering device and / or the conveying unit according to the independent adjustment instructions.

[0015] According to one embodiment of the present invention, the measuring device is a loss-in-weight weighing scale, and the mixing device is a twin-shaft paddle mixer.

[0016] According to one embodiment of the present invention, the conveying unit includes two variable frequency screw conveyors arranged in parallel, and an annular distributor disposed at the feed inlet of the molten salt chlorination furnace, wherein the annular distributor has uniformly opened discharge ports in the circumference.

[0017] According to one embodiment of the present invention, each raw material silo is equipped with an electromagnetic vibration arch-breaking device and a pneumatic gate valve at its bottom; the drive shaft of the conveying unit is equipped with a torque sensor, and the discharge port of the mixing device is connected to a buffer container equipped with a material level sensor.

[0018] By adopting the above technical solution, the present invention has at least one of the following advantages compared with the prior art: (1) Excellent mixing uniformity: Through the precise speed and time control of the twin-shaft paddle mixer, the titanium slag, petroleum coke and sodium chloride are efficiently mixed, with a mixing uniformity of ≥95%, which effectively avoids local reaction imbalance in the furnace, improves the titanium slag conversion rate and chlorine utilization rate, and the titanium slag conversion rate can be stabilized at over 95%. (2) Precise and efficient control: The composition adaptive control mechanism is adopted, and the feed rate control response time is ≤15min. It can match the changes in the composition of molten salt in the furnace in real time to ensure the stable reaction. Compared with the traditional fixed feed method, the fluctuation of the composition of molten salt in the furnace is reduced by more than 80%. (3) Adapting to large-scale requirements: The system can accurately match large molten salt chlorination furnaces with a capacity of 160t / d and above. Through the dual parallel conveying and ring material distribution design, it can meet the requirements of large flow continuous feeding. The feeding capacity can reach 20~50t / h. Compared with the existing small and medium capacity feeding system, the adaptability is significantly improved. (4) High operational safety: Through torque monitoring, material level monitoring and safety interlock design, problems such as raw material blockage, material interruption and material overflow are effectively avoided, and the failure rate of the feeding system is reduced by more than 90%; the whole process is automatically controlled, reducing manual intervention and reducing the intensity of operation and human error; (5) Significant economic benefits: Precise proportioning and control can reduce raw material waste and increase raw material utilization by 10%~15%; at the same time, it ensures that the chlorination reaction proceeds stably and efficiently, and reduces downtime losses caused by reaction imbalance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the feeding system of a molten salt chlorination furnace according to an embodiment of the present invention; Figure 2 This is a process flow diagram of a feeding control method for a molten salt chlorination furnace according to an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0022] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0023] To address the shortcomings of existing molten salt chlorination furnace feeding systems and methods, such as low proportioning accuracy, poor mixing uniformity, lagging feed rate control, lack of adaptive component control mechanism, and insufficient adaptability to large-scale applications, this invention aims to achieve precise raw material proportioning, efficient mixing, and real-time adaptive control of the feed rate through a system structure of "raw material supply - metering mixing - conveying control" and a closed-loop method of "proportioning setting - multi-component mixing - dynamic component control," thereby ensuring the stable and efficient operation of large-scale molten salt chlorination furnaces.

[0024] According to one aspect of the present invention, a feeding system for a molten salt chlorination furnace is provided, particularly suitable for molten salt chlorination furnaces with a capacity of 160 t / d and above. For example... Figure 1 As shown, the system generally includes: a raw material supply unit, a metering and mixing unit, a conveying unit, and a control unit. Specifically, the raw material supply unit may include multiple independent raw material bins; the metering and mixing unit is located downstream of the raw material supply unit; the conveying unit is located downstream of the metering and mixing unit; and the control unit is signal-connected to the metering device, the conveying unit, and the component detection device in the molten salt chlorination furnace.

[0025] Raw material supply unit Multiple independent raw material silos can be used to store raw materials such as titanium slag, petroleum coke, and sodium chloride. Each silo is independently located to avoid cross-contamination between different raw materials, ensuring raw material purity and proportioning accuracy. Each silo is equipped with a dustproof sealing cover on top and a discharge control valve and anti-bridging device at the bottom. The anti-bridging device is preferably an electromagnetic vibration arch-breaking device, with a vibration frequency adjustable within the range of 20~50Hz. Through periodic vibration, it breaks down the bridging structure of materials at the bottom of the silo, effectively preventing raw material blockage. The discharge control valve is preferably a pneumatic gate valve, which can quickly respond to control commands and achieve controlled discharge of raw materials.

[0026] Metering Mixing Unit The metering and mixing unit, located downstream of the raw material supply unit, may include metering devices connected to the outlets of each raw material silo and mixing devices located downstream of the metering devices. The metering devices are used to independently and accurately measure each raw material to ensure proportioning accuracy. The mixing devices are used to thoroughly mix the metered raw materials.

[0027] In embodiments of the present invention, the metering device is preferably a loss-in-weight weighing scale, which can continuously and accurately measure the feed amount and provide real-time feedback to the control unit, with a metering accuracy of ≤±0.5%. The mixing device is preferably a twin-shaft paddle mixer, whose inlet is connected to the outlet of three loss-in-weight weighing scales. The machine body is equipped with intermeshing propeller blades, and the blade speed can be steplessly adjusted within the range of 50~80 r / min to generate strong shearing, convection and diffusion effects on multi-component materials, thereby achieving efficient mixing.

[0028] More preferably, the discharge port of the mixing device is connected to a buffer container, and a level sensor is installed inside the buffer container. The buffer container is used to temporarily store the mixed material, and the level sensor inside monitors the material level in real time and feeds the signal back to the control unit to trigger the level interlock control in the safety interlock step. In one embodiment of the present invention, the buffer hopper is located below the discharge port of the twin-shaft paddle mixer, and a level sensor is installed at each of its upper and lower ends to monitor the upper limit (80% hopper capacity) and lower limit (20% hopper capacity) of the material level, respectively.

[0029] Conveying unit A conveying device located downstream of the metering and mixing unit can be connected to the feed inlet of the molten salt chlorination furnace to transport the mixture into the furnace. The conveying unit includes at least one variable frequency conveyor, and the control unit adjusts the feeding rate by regulating the operating frequency of the variable frequency conveyor.

[0030] In one embodiment of the present invention, the conveying unit includes two parallel-arranged variable frequency screw conveyors, an annular distributor, and two sets of torque sensors. The feed inlets of both variable frequency screw conveyors are connected to the bottom outlet of the buffer hopper. The conveyor motors use variable frequency speed regulation with a speed range of 10~50 r / min. The annular distributor is installed directly below the top feed inlet of the molten salt chlorination furnace and communicates with the discharge outlets of the two variable frequency screw conveyors. The distributor has evenly spaced discharge outlets to ensure that the material falls evenly into the furnace. The two sets of torque sensors are respectively installed on the drive shafts of the two screw conveyors to monitor the feeding resistance in real time. The two parallel-arranged conveyors can achieve continuous high-flow-rate conveying, meeting the feeding requirements of large molten salt chlorination furnaces. The annular distributor evenly distributes the material along the circumference of the furnace top, preventing material from concentrating in a certain area of ​​the furnace and ensuring uniform dispersion of the material on the surface of the molten salt in the furnace.

[0031] Control Unit The control unit can use a PLC controller as the core control module, and connect to the metering device, the conveying unit and the component detection device in the molten salt chlorination furnace. Based on the received signals, it can execute the feeding control method of any of the following embodiments.

[0032] In a preferred embodiment of the present invention, the control unit can receive temperature, pressure, chlorine flow rate signals and molten salt composition (TiO2, C content) detection signals in the molten salt chlorination furnace through the signal acquisition module, and simultaneously receive metering data from the loss-in-weight weighing scale, material level signals from the material level sensor and resistance signals from the torque sensor; and through the signal output module, it can control the pneumatic gate valve and vibratory arch-breaking device of the raw material storage unit, the loss-in-weight weighing scale and twin-shaft paddle mixer of the metering and mixing unit, and the variable frequency screw conveyor of the conveying and control unit to achieve fully automated control of the entire process.

[0033] According to another aspect of the present invention, a feeding control method for a molten salt chlorination furnace is also provided, applicable to feeding control of molten salt chlorination furnaces with a capacity of 160 t / d and above. For example... Figure 2 As shown, the feed control method includes the following steps: Proportioning setting: Set the target proportion of each raw material according to the process requirements, and feed each raw material synchronously according to the target proportion; Multi-component mixing: The raw materials fed according to the formula are transported to the mixing device for mixing, and the mixture is then transported to the molten salt chlorination furnace; Dynamic component control: Real-time acquisition of molten salt component detection signals in the molten salt chlorination furnace, and calculation of the deviation between the current component and the target component.

[0034] During the proportioning process, target proportions for each raw material, such as titanium slag, petroleum coke, and sodium chloride, are set according to the requirements of the molten salt chlorination reaction. The PLC controller sends instructions to each metering device, and each raw material is fed synchronously according to the target proportion. Through the precise setting of the target proportion and synchronous feeding, the accuracy of the proportion of each raw material is ensured, laying the foundation for the stability of subsequent mixing and reaction.

[0035] In one embodiment of the present invention, according to the requirements of molten salt chlorination reaction, the mass ratio of titanium slag, petroleum coke and sodium chloride is preset to 1:(0.08~0.14):(0.1~0.5). The PLC controller sends instructions to three loss-in-weight weighing scales, and the three weighing scales feed materials synchronously and accurately according to the set ratio. The feeding rate is dynamically matched according to the capacity requirements of the molten salt chlorination furnace.

[0036] In the multi-component mixing process, the raw materials fed according to the specified proportions are transported to a mixing device for mixing, and the mixture is then conveyed to the molten salt chlorination furnace. The forced stirring action of the mixing device ensures that the titanium slag, petroleum coke, sodium chloride, and other components are thoroughly and uniformly mixed, preventing localized reaction imbalances within the furnace due to uneven material distribution. The mixed material is then temporarily stored in a buffer container to eliminate the impact of upstream feed fluctuations on downstream conveying, ensuring the continuity of subsequent feeds.

[0037] In one embodiment of the present invention, the three raw materials are weighed by a loss-in-weight weighing scale and then simultaneously fed into a twin-shaft paddle mixer. The speed of the mixer paddles is adjusted to 50~80 r / min and the mixing time is controlled at 30~60 s to ensure that the material mixing uniformity is ≥95% (detected by the coefficient of variation method, the coefficient of variation is ≤5%). After mixing, the material is temporarily stored in a buffer hopper to ensure the continuity of subsequent feeding.

[0038] During the dynamic component control process, the molten salt component detection signal inside the molten salt chlorination furnace is acquired in real time, and the deviation value between the current component and the target component is calculated. Dynamic component control is the core step of the method of this invention, specifically including the following sub-steps: (1) When the deviation value exceeds the preset threshold, the target correction amount of the required feed rate of each raw material is calculated independently based on the deviation value. The setting of the preset threshold can avoid frequent adjustments caused by small fluctuations in the detection signal and ensure the stability of the system operation.

[0039] (2) Adjust the feeding rate of the corresponding raw materials according to the target correction amount so that the actual feeding rate of each raw material deviates from the target ratio, in order to compensate for the deviation of the molten salt composition in the furnace. That is, during the adjustment process, each raw material temporarily deviates from the initially set target ratio. By increasing or decreasing the feeding amount of specific raw materials in a targeted manner, the precise compensation for the deviation of the composition in the furnace can be achieved.

[0040] (3) The feeding rate of each raw material is restored to the target ratio after the composition of the molten salt in the furnace is restored to the set range. This restoration mechanism enables the system to return to the state of feeding according to the target ratio after completing the composition correction, forming a complete dynamic balance process of "disturbance-compensation-restoration".

[0041] The molten salt composition obtained in real time includes at least the TiO2 content and C content. TiO2 and C are the most critical control indicators in the molten salt chlorination reaction. The TiO2 content reflects the degree of conversion of titanium slag, and the C content reflects the sufficiency of reducing agent. Together, they determine the efficiency of the chlorination reaction and the quality of the product.

[0042] Preferably, the raw materials include titanium slag, petroleum coke, and sodium chloride. When the TiO2 content or C content is higher than the upper limit of the set value, the feeding rate of titanium slag or petroleum coke is reduced respectively; when the TiO2 content or C content is lower than the lower limit of the set value, the feeding rate of titanium slag or petroleum coke is increased respectively. Through the reverse adjustment mechanism, the precise correction of the molten salt composition in the furnace is achieved. The feeding rate of sodium chloride is adjusted in conjunction with the total feed amount according to the target ratio to maintain the medium balance of the molten salt system.

[0043] In one embodiment of the present invention, the PLC controller receives the molten salt composition detection signal in the furnace in real time. When the TiO2 or C content in the molten salt composition increases by 1%, the PLC controller immediately adjusts the opening of the frequency converter of the variable frequency screw conveyor to increase the feeding rate by 5% to 8%. When the TiO2 or C content decreases by 1%, the PLC controller reduces the feeding rate by 3% to 5% to ensure that the molten salt composition in the furnace remains stable within a reasonable range.

[0044] More preferably, the dynamic control process of the composition also acquires at least one of the furnace temperature signal, pressure signal, and chlorine flow rate signal, and comprehensively calculates the target correction amount. The molten salt chlorination reaction is affected by multiple factors such as temperature, pressure, and chlorine supply. Introducing temperature, pressure, and chlorine flow rate signals as auxiliary correction parameters can further improve the accuracy and adaptability of the control.

[0045] The feeding control method also includes safety interlocks: real-time monitoring of the feeding resistance of the conveying unit; when the feeding resistance exceeds a set threshold, the anti-bridging device of the corresponding raw material silo is activated. Increased feeding resistance indicates that material bridging or blockage may have occurred at the outlet of the corresponding raw material silo or in the conveying channel. Activating the anti-bridging device breaks the material bridging structure and restores smooth feeding. Simultaneously, the material level in the buffer container temporarily storing the mixed material is monitored in real-time. When the material level is below the lower limit, the feeding rate and / or mixing rate are increased; when the material level is above the upper limit, the feeding rate and / or mixing rate are decreased. Through interlocking control of the upper and lower material levels, conveying interruptions due to material shortages or equipment malfunctions due to material overflow are prevented.

[0046] In one embodiment of the present invention, when the torque sensor detects that the feeding resistance of the screw conveyor exceeds a set threshold (≥50 N•m), the PLC controller immediately issues an alarm signal and activates the vibration arch-breaking device corresponding to the raw material storage unit, increasing the vibration frequency to 40~50 Hz, while reducing the speed of the screw conveyor to avoid raw material blockage; when the lower limit level sensor in the buffer hopper is triggered, the PLC controller issues a low level alarm and increases the feeding rate of the loss-in-weight weighing scale and the mixing rate of the twin-shaft paddle mixer to ensure that the material level is maintained within a reasonable range; when the upper limit level sensor is triggered, the feeding and mixing rates are reduced to prevent material overflow.

[0047] The following are specific embodiments of a feeding system and feeding control method for a molten salt chlorination furnace according to the present invention.

[0048] Example (1) Raw material ratio setting: According to the requirements of molten salt chlorination reaction, the mass ratio of titanium slag, petroleum coke and sodium chloride is set to 1:0.12:0.3. The PLC controller instructs three loss-in-weight weighing scales to feed materials synchronously according to this ratio, and the total feeding rate is set to 8.5t / h.

[0049] (2) Multi-component high-efficiency mixing: After being weighed by a loss-in-weight weigher, the three raw materials enter the twin-shaft paddle mixer. The speed of the mixer paddle is adjusted to 65 r / min and the mixing time is controlled at 45 s. After testing, the material mixing uniformity is 96.2% and the coefficient of variation is 3.8%, which meets the mixing requirements. The mixed material enters the buffer hopper for temporary storage.

[0050] (3) Adaptive control of composition: During operation, the PLC controller receives the molten salt composition detection signal in the furnace in real time. When the C content in the molten salt increases by 1.2%, it immediately links to increase the opening of the frequency converter of the variable frequency screw conveyor, increasing the feed rate from 8.5t / h to 9.2t / h (an increase of 8.3%). The control response time is 12min. Subsequent detection shows that the C content in the furnace gradually returns to a reasonable range, and the reaction state of the chlorination furnace is stable.

[0051] (4) Safety interlock operation: During operation, due to slight bridging at the bottom of the titanium slag silo, the torque sensor detected that the feed resistance rose to 52 N•m. The PLC controller immediately issued an alarm signal and started the vibration breaking device of the titanium slag silo, increasing the vibration frequency to 45 Hz. At the same time, the speed of the screw conveyor was reduced from 35 r / min to 25 r / min. After 1 minute, the feed resistance dropped back to 35 N•m, and the blockage problem was solved. The material level in the buffer hopper was always maintained within a reasonable range of 30% to 70%, and no low or high material level alarms occurred.

[0052] In this embodiment, the uniformity of material mixing was detected using the coefficient of variation method, the molten salt composition was detected using X-ray fluorescence spectroscopy, and the response time of feed rate regulation was calculated by the time difference between composition change and regulation action.

[0053] After continuous and stable operation testing, the fluctuation range of molten salt composition in the chlorination furnace in this embodiment is ≤0.8%, and the feeding system does not experience blockage, material interruption or other faults, and the operation stability is good.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications or equivalent substitutions made to the present invention without departing from the spirit and scope thereof should be covered within the protection scope of the claims of the present invention.

[0055] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of the present invention is limited to these examples; within the framework of the embodiments of the present invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention.

Claims

1. A method for controlling the feeding of a molten salt chlorination furnace, characterized in that, The feed control method applicable to molten salt chlorination furnaces with a capacity of 160 t / d and above includes the following steps: Proportion setting: Set the target proportion of each raw material according to the process requirements, and feed each raw material synchronously according to the target proportion; Multi-component mixing: The raw materials fed according to the formula are transported to the mixing device for mixing, and the mixture is then transported to the molten salt chlorination furnace; Dynamic component control: Real-time acquisition of molten salt component detection signals in the molten salt chlorination furnace, and calculation of the deviation between the current component and the target component; in, When the deviation value exceeds the preset threshold, the target correction amount of the required feeding rate of each raw material is calculated independently based on the deviation value. The feeding rate of the corresponding raw materials is adjusted according to the target correction amount, so that the actual feeding rate of each raw material deviates from the target ratio, in order to compensate for the deviation of the molten salt composition in the furnace. The feeding rate of each raw material will be restored to the target ratio once the molten salt composition in the furnace returns to the set range.

2. The feeding control method according to claim 1, characterized in that, The composition of the molten salt obtained in real time includes at least TiO2 content and C content.

3. The feeding control method according to claim 2, characterized in that, The raw materials include titanium slag, petroleum coke, and sodium chloride. When the TiO2 content or C content is higher than the upper limit of the set value, the feeding rate of titanium slag or petroleum coke is reduced respectively. When the TiO2 content or C content is lower than the set lower limit, the feeding rate of titanium slag or petroleum coke is increased respectively.

4. The feeding control method according to claim 1, characterized in that, In the dynamic control step of the composition, at least one of the furnace temperature signal, pressure signal and chlorine flow signal is also acquired, and the target correction amount is calculated in combination.

5. The feeding control method according to claim 1, characterized in that, The feeding control method also includes a safety interlock step: The feeding resistance of the conveying unit is monitored in real time. When the feeding resistance exceeds a set threshold, the anti-bridging device of the corresponding raw material bin is activated; and / or, The material level in the buffer container that temporarily stores the mixed material is monitored in real time. When the material level is below the lower limit, the feeding rate and / or mixing rate are increased. When the material level is above the upper limit, the feeding rate and / or mixing rate are decreased.

6. A feeding system for a molten salt chlorination furnace, characterized in that, A system applicable to molten salt chlorination furnaces with a capacity of 160 t / d and above, and implementing the feed control method according to any one of claims 1-5, the system comprising: The raw material supply unit includes multiple independent raw material warehouses; A metering and mixing unit is located downstream of the raw material supply unit, including a metering device connected to the outlet of each raw material silo and a mixing device located downstream of the metering device. The conveying unit is located downstream of the metering and mixing unit and is connected to the feed inlet of the molten salt chlorination furnace; The control unit is connected to the metering device, the conveying unit, and the component detection device in the molten salt chlorination furnace, and performs dynamic component control based on the received signals.

7. The feeding system according to claim 6, characterized in that, The control unit is configured to receive the real-time feed rate signal from the metering device and the real-time detection signal of the molten salt composition, generate independent adjustment commands for the feed rate of each raw material, and control the metering device and / or the conveying unit according to the independent adjustment commands.

8. The feeding system according to claim 6, characterized in that, The measuring device is a loss-in-weight weighing scale, and the mixing device is a twin-shaft paddle mixer.

9. The feeding system according to claim 6, characterized in that, The conveying unit includes two parallel variable frequency screw conveyors and an annular feeder located at the feed inlet of the molten salt chlorination furnace, with the annular feeder having uniformly spaced discharge outlets around its circumference.

10. The feeding system according to claim 6, characterized in that, Each raw material silo is equipped with an electromagnetic vibration arch-breaking device and a pneumatic gate valve at the bottom; The drive shaft of the conveying unit is equipped with a torque sensor, and the discharge port of the mixing device is connected to a buffer container equipped with a material level sensor.

Images