Electrostatic suppression device, drying apparatus and drying method

Abstract

This invention discloses an electrostatic suppression device, drying equipment, and drying method, relating to the field of drying equipment technology. It includes: an insulating mounting base for installation in the drying chamber of the drying equipment and for electrical isolation from the drying equipment; conductive fibers comprising a matrix portion and a main body portion, the matrix portion being mounted on the insulating mounting base and the main body portion extending into the working area of ​​the drying chamber for contact with the material to be dried; and a grounding mechanism electrically connected to the matrix portion and used for grounding. This mechanism directly captures charges generated by gas-solid friction, particle collisions, and newly formed surfaces, reducing the risk of electrostatic accumulation and explosion, and solving the problem that the static electricity of the insulating material particles themselves cannot be eliminated through equipment grounding.

Description

Technical Field

[0001] This invention relates to the field of drying equipment technology, and in particular to an electrostatic suppression device, drying equipment, and drying method. Background Technology

[0002] Drying energetic materials (such as propellants, explosives, and their raw materials) is a critical step in the production process, decisively affecting the final performance, safety, and storage stability of the product. Due to their inherent flammability and explosiveness, the drying process must be carried out under strict control, with electrostatic accumulation and discharge being the primary risk sources for combustion and explosion accidents. In particular, the large-scale safe application of fluidized bed drying technology in the field of energetic materials has been limited by its inherent and insurmountable problem of electrostatic generation and accumulation.

[0003] The mechanism of static electricity generation in a fluidized bed is complex and intense, and its main sources are as follows: (1) Gas-solid triboelectric charging: The high-speed flow of processing gas (such as hot air or nitrogen) generates intense relative motion and friction with the surface of material particles, which is one of the main sources of static electricity; (2) Solid-solid friction and collision electrification: High-frequency and intense collisions and frictions occur between solid particles in the fluidized state; at the same time, solid particles also continuously collide and rub against the walls of the fluidized bed reactor, internal components, collection bags, and connecting pipes. These interactions lead to the transfer and accumulation of charge between the contact surfaces; (3) Charged new surfaces: During the drying process, as the particles continue to dry and become finer, or as they break apart due to collisions, many new surfaces are generated. These new surfaces disrupt the original charge balance of the original particle surfaces, thus carrying a large amount of new surface charge.

[0004] The combined effect of these multiple mechanisms leads to the rapid accumulation of a large amount of static charge on the surface of energetic material particles within the fluidized bed. If these charges cannot be dissipated in a timely and effective manner, they will form an extremely high electrostatic potential, which can easily generate spark discharges and become a dangerous source of ignition for sensitive energetic materials.

[0005] Methods for eliminating static electricity in the fluidized bed drying process include grounding the fluidized bed equipment, adjusting process parameters (such as increasing humidity), and adding a small amount of antistatic agent to the formulation. However, these methods often have drawbacks such as incomplete static electricity elimination, sacrifice of drying efficiency, and impact on product performance.

[0006] In summary, existing technologies have failed to provide a fundamental solution for directly, proactively, and safely eliminating static electricity in particles without compromising the core advantages of fluidized bed processes (high efficiency and uniformity). A significant technological barrier remains to be overcome between the high efficiency potential of fluidized bed drying technology and the safety requirements of energetic materials production. Summary of the Invention

[0007] The purpose of this invention is to provide an electrostatic suppression device, drying equipment, and drying method to solve the problems existing in the prior art. It can directly capture the charge generated by gas-solid friction, particle collision, and new surface formation, reduce the risk of electrostatic accumulation and explosion, and solve the problem that the static electricity of the insulating material particles to be dried cannot be eliminated by grounding the equipment.

[0008] To achieve the above objectives, the present invention provides the following solution: The present invention provides an electrostatic suppression device, comprising: An insulating mounting base is provided for installation in the drying chamber of a drying device and for electrical isolation from the drying device. The conductive fiber has a matrix portion and a main body portion. The matrix portion is mounted on the insulating mounting base, and the main body portion extends to the working area of ​​the drying chamber for contact with the material to be dried. A grounding mechanism, which is electrically connected to the base portion and is used for grounding.

[0009] Optionally, the main body has a flexible structure to reduce resistance to the material to be dried in motion.

[0010] Optionally, the volume resistivity of the conductive fiber is 10. 3 Up to 10 8 Ω∙cm, used to gradually transfer the static charge generated in the drying chamber.

[0011] Optionally, the conductive fiber is made entirely of a conductive polymer composite material.

[0012] Optionally, the grounding mechanism is equipped with an impedance adjustment mechanism, and the grounding mechanism is grounded through the impedance adjustment mechanism.

[0013] Optionally, the impedance adjustment mechanism is equipped with an electrostatic control mechanism, which includes an electrostatic sensor and a controller. The electrostatic sensor is installed in the drying chamber to monitor the electrostatic potential in the drying chamber in real time. The controller is electrically connected to the electrostatic sensor and the impedance adjustment mechanism, and controls the impedance of the impedance adjustment mechanism according to a preset electrostatic safety threshold.

[0014] Optionally, multiple electrostatic sensors are provided and are evenly arranged in the drying chamber along the conveying direction of the material to be dried.

[0015] A drying device is also provided, including a drying device body and an electrostatic suppression device as described above. The electrostatic suppression device is provided with a plurality of insulated mounting bases and conductive fibers arranged in groups. Each of the insulated mounting bases is evenly arranged in the drying chamber of the drying device body at least along the conveying direction of the material to be dried. Each of the conductive fibers is correspondingly arranged on each of the insulated mounting bases. The grounding mechanism of the electrostatic suppression device is electrically connected to the base portion of each of the conductive fibers.

[0016] Optionally, the drying equipment body is a fluidized bed, but is not limited to the fluidized bed.

[0017] A drying method using the drying equipment described above is also provided, comprising the following steps: S1. Load the material to be dried into the drying chamber of the drying equipment body; S2. Introduce processing gas to dry the material to be dried; S3. During the drying process, the material to be dried comes into contact with the main body of the conductive fiber, and the static charge on the surface of the material to be dried is conducted away through the main body of the conductive fiber, the matrix of the conductive fiber, and the grounding mechanism. S4. After drying is complete, remove the dried material.

[0018] The present invention achieves the following technical effects compared to the prior art: The electrostatic suppression device disclosed in this invention has conductive fibers disposed within the drying chamber of a drying equipment. The main body of the conductive fibers extends into the working area of ​​the drying chamber, directly contacting the particles of the material to be dried. This provides a safe channel for the static charge on the surface of the particles to be grounded. Therefore, this application actively places a channel for the safe discharge of charge to the ground within the charge generation area. By introducing conductive fibers and employing a contact-type charge dissipation mechanism, it can directly capture the charge generated by gas-solid friction, particle collisions, and newly formed surfaces, reducing the risk of static electricity accumulation and explosion. It also solves the problem that the static electricity of the insulated particles to be dried cannot be eliminated through equipment grounding. In summary, this invention actively dissipates charge at the source without affecting the efficient and uniform drying process of the drying equipment, possessing advantages such as inherent safety and zero pollution. Furthermore, due to the simple structure and high reliability of the device, it is easy to retrofit and install on existing drying equipment, significantly improving the safety level of existing drying equipment for drying energetic materials, and has strong applicability and widespread adoption. 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 embodiments 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 based on these drawings without creative effort.

[0020] Figure 1 This is a partial structural diagram of a drying device in one example disclosed in this invention; Figure 2 This is a schematic diagram of the combination of conductive fiber and insulating mounting base in an example disclosed in this invention; Figure 3 This is an axonometric view of a conductive fiber in an example disclosed in this invention; Among them, 1-drying equipment, 2-insulating mounting base, 3-base part, 4-main body part, and 5-drying chamber. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The purpose of this invention is to provide an electrostatic suppression device, drying equipment, and drying method to solve the problems existing in the prior art. It can directly capture the charge generated by gas-solid friction, particle collision, and new surface formation, reduce the risk of electrostatic accumulation and explosion, and solve the problem that the static electricity of the insulating material particles to be dried cannot be eliminated by grounding the equipment.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figures 1 to 3 As shown, the present invention provides an electrostatic suppression device, including an insulating mounting base 2, conductive fibers, and a grounding mechanism; the insulating mounting base 2 is used to be installed in the drying chamber 5 of the drying equipment 1 and is used for electrical isolation from the drying equipment 1. It can be understood that the insulating mounting base 2 is fixed to the inner wall or internal components of the drying chamber 5; the conductive fibers have a base portion 3 and a main body portion 4. The base portion 3 is installed on the insulating mounting base 2, and the main body portion 4 extends to the working area of ​​the drying chamber 5 for contact with the material to be dried. It can be understood that the main body portion 4 is a fiber array; the grounding mechanism is electrically connected to the base portion 3 and is used for grounding.

[0025] It should be noted that the base part 3 has an integral structure, such as a plate structure, so as to facilitate the conduction of the main body part 4 as a whole and transfer the charge to the grounding mechanism.

[0026] Based on the above embodiments, the grounding operation of the grounding mechanism can be achieved by connecting a conductor to the base part 3, leading the conductor out of the drying equipment 1, and then connecting it to the grounding mechanism. Preferably, a low-resistance conductor is used to provide a smooth path for charge, prevent charge accumulation, and instantly conduct current or static electricity to the ground. The low-resistance conductor can be made of copper wire or the like, but is not limited to copper wire.

[0027] The electrostatic suppression device disclosed in this invention has conductive fibers disposed within the drying chamber 5 of the drying equipment 1, with the main body 4 of the conductive fibers extending into the working area of ​​the drying chamber 5 and directly contacting the particles of the material to be dried. This provides a safe channel for the static charge on the surface of the particles to be dried to be discharged to the ground. Thus, this application actively places a channel for the safe discharge of charge to the ground within the charge generation area. By introducing conductive fibers and employing a contact-type charge dissipation mechanism, it can directly capture the charge generated by gas-solid friction, particle collisions, and newly formed surfaces, reducing the risk of static electricity accumulation and combustion / explosion. It also solves the problem that the static electricity of the insulated particles to be dried cannot be eliminated through equipment grounding. In summary, this invention actively dissipates charge at the source without affecting the efficient and uniform drying process of the drying equipment 1, possessing advantages such as inherent safety and zero pollution. Furthermore, due to the simple structure and high reliability of the device, it is easy to retrofit and install on existing drying equipment 1, significantly improving the safety level of existing drying equipment 1 for drying energetic materials, and has strong applicability and scalability.

[0028] In some specific examples, the drying chamber 5 has a cylindrical structure, and both the insulating mounting base 2 and the conductive fiber matrix portion 3 have cylindrical structures that match the inner wall structure of the drying chamber 5, with the main body portion 4 of the conductive fiber evenly distributed on the inner circumference of its matrix portion 3. Alternatively, both the insulating mounting base 2 and the conductive fiber matrix portion 3 have strip-shaped structures and are installed at equal intervals along the circumference of the drying chamber 5 on the inner wall of the drying chamber 5. Alternatively, both the insulating mounting base 2 and the conductive fiber matrix portion 3 have annular structures and are coaxially installed on the inner wall of the drying chamber 5, and are evenly distributed along the axial direction of the drying chamber 5. Alternatively, the insulating mounting base 2 has a cylindrical structure, and the conductive fiber matrix portion 3 is arrayed and installed on the insulating mounting base 2, and so on.

[0029] In one embodiment, the main body 4 has a flexible structure to reduce resistance to the moving material to be dried. The flexibility of the main body 4 minimizes resistance to the high-speed moving material, does not interfere with the fluidization state of the material, does not disrupt the airflow distribution, and does not affect the particle mixing and drying kinetics, thus fully preserving the core technological advantages of the drying equipment 1: high efficiency and uniform drying. This is unparalleled by methods such as adding antistatic agents or changing process parameters.

[0030] The main body portion 4 has a diameter of 0.05-0.5 mm and a length of 20-150 mm. Different diameters and / or lengths of the main body portion 4 can be selected depending on the type of material to be dried or the operating conditions to ensure effective direct contact between the main body portion 4 and the particles of the material to be dried. The selection of the diameter and / or length of the main body portion 4 is not limited to the diameters and lengths mentioned above.

[0031] In one embodiment, the volume resistivity of the conductive fiber is 10. 3 Up to 10 8 Ω∙cm is used to gradually transfer the static charge generated within the drying chamber 5. Specifically, conductive fibers with moderate resistivity are used as the static charge transfer medium. The static charge dissipation process is a slow dissipation limited by the resistance of the conductive fibers, rather than an instantaneous spark discharge. This is an intrinsically safe design, completely avoiding the secondary risks associated with the use of high-voltage ionization or radioactive sources.

[0032] Based on the above implementation methods, in some cases, the bristle structure itself can be adjusted to select a bristle structure with a corresponding volume resistivity. According to the law of resistance, resistance R is inversely proportional to cross-sectional area A; increasing the diameter increases the cross-sectional area A and decreases the resistance R; decreasing the diameter decreases the cross-sectional area A and increases the resistance R. Therefore, in specific applications, the length and diameter of the bristle structure are first selected based on the conductivity of the conductive fiber material to adjust the bristle structure to the required resistivity.

[0033] In another scenario, conductive fibers with the appropriate volume resistivity are obtained by selecting the desired materials. The conductive fibers are entirely made of conductive polymer composite materials. These conductive polymer composite materials include, but are not limited to, doped polyaniline, polypyrrole, and polythiophene. To ensure the flexibility of the bristle structure, composite materials of the above materials and elastomers are also included. For the selection of elastomers, silicone rubber or thermoplastic polyurethane can be used.

[0034] In one embodiment, the grounding mechanism is equipped with an impedance adjustment mechanism, through which the grounding mechanism is grounded. The impedance value of the grounding circuit can be adjusted according to actual needs, thereby controlling the rate and magnitude of static charge discharge. This avoids electric sparks caused by excessive instantaneous discharge current while ensuring effective discharge of static charge, achieving both safe discharge and explosion-proof effects. Therefore, the conductive fiber body 4 of this invention extends into the working area, directly contacting the particles of the material to be dried, providing a safe channel for the static charge on the surface of the material to be dried to be discharged to the ground through an adjustable impedance.

[0035] In one embodiment, the impedance adjustment mechanism is equipped with an electrostatic control mechanism, which includes an electrostatic sensor and a controller. The electrostatic sensor is installed inside the drying chamber 5 to monitor the electrostatic potential inside the drying chamber 5 in real time. The controller is electrically connected to the electrostatic sensor and the impedance adjustment mechanism, and controls the impedance of the impedance adjustment mechanism according to a preset electrostatic safety threshold. This invention, by combining the impedance adjustment mechanism with the electrostatic control mechanism, achieves real-time monitoring and intelligent feedback control of the electrostatic level, dynamically matching the electrostatic suppression strength with the actual charge generation rate, thus possessing the advantages of adaptive control and achieving an optimal balance between safety and economy.

[0036] To improve the effectiveness of overall monitoring of static charge in drying chamber 5, multiple electrostatic sensors are installed and evenly arranged in drying chamber 5 along the conveying direction of the material to be dried.

[0037] Based on the above implementation method, the controller is also equipped with an alarm mechanism. The controller monitors the status of the grounding circuit or the discharge current parameters in real time. Once the value exceeds the preset electrostatic safety threshold, it immediately sends a trigger signal to the alarm mechanism connected to the controller, which then issues an alarm signal, such as an audible and visual alarm. Through the alarm mechanism, operators are immediately alerted to potential safety hazards when the electrostatic discharge function fails or malfunctions, thereby preventing fires or explosions caused by static electricity accumulation.

[0038] Furthermore, a drying device 1 is also provided, including a drying device 1 body and an electrostatic suppression device as described above. The electrostatic suppression device is provided with multiple insulated mounting bases 2 arranged in groups and conductive fibers. Each insulated mounting base 2 is evenly arranged in the drying chamber 5 of the drying device 1 body at least along the conveying direction of the material to be dried. Each conductive fiber is correspondingly arranged on each insulated mounting base 2. The grounding mechanism of the electrostatic suppression device is electrically connected to the matrix portion 3 of each conductive fiber. The drying device 1 disclosed in this invention forms a safe and efficient charge dissipation channel by having the main body portion 4 of the conductive fiber directly contact the particles of the material to be dried, realizing the immediate dissipation of charge from the source. Thus, while fully retaining the drying advantages of the drying device 1, it completely eliminates the risk of electrostatic combustion and explosion, and can ensure the overall destatic effect of the drying device 1.

[0039] In some specific examples, for the uniform arrangement of each insulating mounting base 2, the insulating mounting base 2 is provided in multiple groups, arranged in layers along the height direction of the drying equipment 1, and / or distributed symmetrically in the horizontal section.

[0040] The drying equipment 1 is a fluidized bed, but not limited to a fluidized bed, with the main body 4 of the conductive fiber extending into the particle fluidization region of the fluidized bed. Addressing the problems of complex electrostatic generation mechanisms and severe accumulation in existing fluidized bed drying technologies for energetic materials, and the low efficiency, significant side effects, or introduction of new risks associated with existing suppression measures, this invention can achieve instantaneous dissipation of charge from its source, thereby completely eliminating the risk of electrostatic combustion and explosion while fully retaining the advantages of fluidized bed drying.

[0041] Furthermore, a drying method using the drying equipment 1 described above is also provided, characterized by comprising the following steps: S1. Load the material to be dried into the drying chamber 5 of the drying equipment 1. S2. Introduce processing gas to dry the material to be dried; S3. During the drying process, the material to be dried comes into contact with the main body 4 of the conductive fiber, and the static charge on the surface of the material to be dried is conducted away through the main body 4 of the conductive fiber, the matrix 3 of the conductive fiber, and the grounding mechanism. S4. After drying is complete, remove the dried material.

[0042] It should be noted that in some examples, the processing gas is a fully dried gas, which is directly used to dry the material to be dried; in other examples, the processing gas is a gas with a certain humidity. In this example, the partial pressure of water vapor in the processing gas is lower than the partial pressure of water vapor on the surface of the material to be dried, the temperature of the processing gas is higher than the dew point of the processing gas to avoid condensation in the drying chamber 5, and the equilibrium relative humidity corresponding to the moisture content of the dried material is higher than the relative humidity of the discharged processing gas.

[0043] Based on the above implementation method, in step S3, the electrostatic potential inside the drying chamber 5 is monitored in real time by the electrostatic sensor of the electrostatic control mechanism, and the impedance of the impedance adjustment mechanism is dynamically adjusted by the controller to keep the electrostatic potential below the safe threshold.

[0044] Based on the above implementation methods, some specific examples are as follows: In a specific example, an electrostatic suppression device is installed inside the stainless steel fluidized bed (400 mm in diameter) drying chamber 5. The conductive fibers of the electrostatic suppression device are made of PANI / TPU composite material with a resistivity of approximately 5 × 10⁻⁶. 4 The conductive fiber body part 4 has a brush structure with a diameter of 0.15 mm and a length of 80 mm, and is Ω·cm in diameter. It is grounded via an impedance adjustment mechanism.

[0045] In the specific drying method, 50 kg of wet spherical propellant particles [8% moisture content, granular material of a certain type of nitramine (RDX-based) composite propellant] are first loaded. Dry hot air at 50°C is introduced, with an empty bed air velocity of 0.8 m / s. During the drying process, the particles frequently come into contact with the brush structure. The bed potential is stably suppressed between -1.2 kV and -1.8 kV, far below the minimum ignition energy potential corresponding to this material (approximately ±5 kV). There is no spark discharge throughout the process, resulting in uniform and efficient drying, with an outlet material moisture content of <0.1%.

[0046] In another specific example, a three-stage series vibrating fluidized bed drying system is used, each stage being 3m long and 0.8m wide. At a distance of 20mm above the distribution plate of each stage of the fluidized bed, staggered insulating mounting bases 2 are installed on each stage of the vibrating fluidized bed drying system. Each insulating mounting base 2 is equipped with conductive fibers made of polyaniline / silicone rubber composite material with a resistivity of 10⁻⁶. 5 The conductive fiber's main body, 4, has a brush-like structure with a length of 40mm. Multiple electrostatic sensors are installed to provide real-time feedback and adjust the impedance adjustment mechanisms of each stage of the vibrating fluidized bed drying system. Wet material (8% moisture content) is continuously fed from the first stage via a screw conveyor, with a processing capacity of 200kg / h. Drying hot air (60℃) is supplied in counter-current contact, and the total material residence time is approximately 45 minutes. Dry material (<0.5% moisture content) is continuously discharged from the end of the third stage.

[0047] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0048] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0049] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An electrostatic suppression device, characterized by, include: An insulating mounting base is provided for installation in the drying chamber of a drying device and for electrical isolation from the drying device. The conductive fiber has a matrix portion and a main body portion. The matrix portion is mounted on the insulating mounting base, and the main body portion extends to the working area of ​​the drying chamber for contact with the material to be dried. A grounding mechanism, which is electrically connected to the base portion and is used for grounding.

2. The static suppression apparatus according to claim 1, wherein The main body has a flexible structure to reduce resistance to the material to be dried in motion.

3. The static suppression apparatus of claim 1, wherein The volume resistivity of the conductive fiber is 10 3 to 10 8 Ω·cm, for gradually transferring the static charge generated in the drying chamber.

4. The static suppression apparatus according to claim 3, wherein The conductive fiber is made entirely of conductive polymer composite material.

5. The static suppression apparatus of claim 1, wherein The grounding mechanism is equipped with an impedance adjustment mechanism, and the grounding mechanism is grounded through the impedance adjustment mechanism.

6. The static suppression apparatus according to claim 5, wherein The impedance adjustment mechanism is equipped with an electrostatic control mechanism, which includes an electrostatic sensor and a controller. The electrostatic sensor is installed in the drying chamber to monitor the electrostatic potential in the drying chamber in real time. The controller is electrically connected to the electrostatic sensor and the impedance adjustment mechanism, and controls the impedance of the impedance adjustment mechanism according to a preset electrostatic safety threshold.

7. The static suppression apparatus of claim 6, wherein Multiple electrostatic sensors are provided and are evenly arranged in the drying chamber along the conveying direction of the material to be dried.

8. A drying apparatus, characterized by The device includes a drying equipment body and an electrostatic suppression device as described in any one of claims 1 to 7. The electrostatic suppression device is provided with a plurality of insulated mounting bases and conductive fibers arranged in groups. Each of the insulated mounting bases is evenly arranged in the drying chamber of the drying equipment body at least along the conveying direction of the material to be dried. Each of the conductive fibers is correspondingly arranged on each of the insulated mounting bases. The grounding mechanism of the electrostatic suppression device is electrically connected to the base portion of each of the conductive fibers.

9. The drying apparatus of claim 8, wherein, The drying equipment body is a fluidized bed, but is not limited to a fluidized bed.

10. A drying method using the drying apparatus according to claim 8 or 9, characterized by, Includes the following steps: S1. Load the material to be dried into the drying chamber of the drying equipment body; S2. Introduce processing gas to dry the material to be dried; S3. During the drying process, the material to be dried comes into contact with the main body of the conductive fiber, and the static charge on the surface of the material to be dried is conducted away through the main body of the conductive fiber, the matrix of the conductive fiber, and the grounding mechanism. S4. After drying is complete, remove the dried material.

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