A de-fogging system and method for waste gases from a wet powder reservoir

Abstract

The application discloses a kind of anti-condensation treatment system and method for containing wet powder repository exhaust gas, including main processing pipeline, switching device, non-condensing treatment branch, anti-condensation branch, dust collector and fan;Gas-solid condensation intensification separator is equipped on anti-condensation branch, and the wall surface of its cylinder is equipped with heat exchange structure for strengthening heat exchange with environment;First sensor is equipped on the upstream of switching device, and second sensor is equipped at the outlet of gas-solid condensation intensification separator;Control unit selects branch according to exhaust gas dew point temperature Td1, when Td1>Tenv+ΔT1, exhaust gas enters anti-condensation branch, condenses and separates in gas-solid condensation intensification separator using environmental cold source, and according to the dew point temperature Td2 of gas after separation, dynamically adjust corresponding fan air volume, so that Td2≤Tenv+ΔT2.The application actively uses environmental cold source to complete condensation dewatering before dust collector, eliminates the thermodynamic condition of condensation in dust collector, can be operated stably for a long time under extremely low temperature, and significantly reduces system resistance and energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of industrial gas treatment, specifically relating to an anti-condensation treatment system and method for waste gas from storage silos containing moist powder, which is particularly suitable for solving the problems of equipment corrosion, dust caking, and excessive emissions caused by condensation of high-humidity waste gas in low-temperature environments. Background Technology

[0002] In industries such as cement, chemicals, and metallurgy, the storage of powdered materials (such as carbide slag, blast furnace slag, and fly ash) is a critical step in the production process. These materials typically carry residual moisture and are at high temperatures upon entering the storage facility (e.g., dry carbide slag powder has a temperature >150℃). This moisture evaporates continuously within the storage silo, creating positive pressure. To ensure safety and control dust emissions, the industry commonly uses baghouse dust collectors installed on the top of the silo. A fan draws the humid waste gas into the collector to maintain a slight negative pressure within the silo. Its core function is to balance the pressure within the silo and purify the waste gas. However, when the ambient temperature is low, this process can cause a sudden drop in temperature below the dew point due to heat exchange and even the mixing of ambient air. This leads to condensation and even freezing of water vapor, causing it to clump inside the baghouse dust collector, resulting in pressure surges, blockages, and the creation of positive pressure within the silo. This poses safety risks and pollutes the environment.

[0003] To address the condensation problem at low ambient temperatures, existing technologies revolve around the core concept of "maintaining the system temperature above the dew point," forming a technical system that combines passive protection (insulation layer, sealing optimization) with active intervention (electric heat tracing, steam heat tracing). However, this concept has a fundamental flaw: it only focuses on maintaining the overall temperature of the exhaust gas, neglecting the localized and severe temperature change effect caused by pulse backflushing inside the bag filter. Specifically, this manifests as follows: (1) When the backflushing compressed air comes into contact with the high-temperature exhaust gas, it forms an instantaneous low-temperature zone on the surface of the filter bag, causing water vapor to condense rapidly in the fiber gaps; (2) Periodic jetting creates an alternating temperature field, causing the condensate to repeatedly vaporize and condense, accelerating dust agglomeration and causing the resistance of the dust collector to increase sharply; (3) The temperature control system cannot track this second-level temperature fluctuation due to response delay. This contradictory state of "global overheating - local undercooling" exposes the essential defect of traditional anti-condensation strategies in thermodynamic design, namely, attempting to control the transient mass and heat transfer problem in a multiphase flow field through a single temperature parameter. It is precisely this limited understanding of the mechanism that has led to a vicious cycle in which the existing system, when operating in winter, “the higher the heat tracing energy consumption, the more severe the local condensation becomes.” Summary of the Invention

[0004] To address the problems existing in the prior art, this invention proposes an anti-condensation treatment system and method for waste gas from a storage facility containing moist powder. By using a gas-solid condensation enhanced separator with an enhanced heat exchange structure with the environment, the system actively utilizes the ambient cold source to condense and dehydrate the waste gas before it enters the dust collector, fundamentally eliminating the localized condensation phenomenon inside the bag filter caused by pulse backflushing, and achieving long-term stable operation of the system in a low-temperature environment.

[0005] This invention is implemented as follows: a condensation prevention treatment system for waste gas from a storage silo containing moist powder, comprising: The main processing pipeline is connected to the top outlet of the powder storage silo; A switching device is installed on the main processing pipeline to receive waste gas from the powder storage tank and selectively distribute the waste gas to a non-condensation treatment branch or an anti-condensation branch. An anti-condensation branch is provided, along which a gas-solid condensation enhanced separator is installed. The gas-solid condensation enhanced separator is used to condense the water vapor in the waste gas into liquid water before it enters the dust collector and separate it from the gaseous waste gas. The cylindrical wall of the gas-solid condensation enhanced separator is provided with a heat exchange structure to enhance heat exchange with the environment. The non-condensing treatment branch and the anti-condensation branch are set in parallel. The outlets of both the non-condensing treatment branch and the anti-condensation branch are connected to a dust collector, and the outlet of the dust collector is connected to a fan. The first sensor is installed on the main processing pipeline upstream of the switching device to obtain the first dew point temperature Td1 of the exhaust gas. The second sensor is installed on the anti-condensation branch at the outlet of the gas-solid condensation enhanced separator to obtain the second dew point temperature Td2 of the gas after condensation and separation. The control unit is configured to perform the following operations: The first dew point temperature Td1 is obtained through the first sensor; when Td1>Tenv + ΔT1, the switching device is controlled to direct the waste gas flow to the anti-condensation branch and flow through the gas-solid condensation enhanced separator; when Td1≤Tenv + ΔT1, the switching device is controlled to direct the waste gas flow to the non-condensation treatment branch. The second dew point temperature Td2 is obtained through the second sensor; the air volume of the fan corresponding to the anti-condensation branch is dynamically adjusted so that Td2 ≤ Tenv + ΔT2; Where Tenv is the real-time ambient temperature, ΔT1 is the preset first temperature margin, and ΔT2 is the preset second temperature margin.

[0006] In the above technical solution, preferably, the values ​​of ΔT1 and ΔT2 are in the range of 0~10℃.

[0007] In the above technical solution, preferably, the gas-solid condensation enhanced separator is a cyclone separator.

[0008] In the above technical solution, a further preferred embodiment is that the heat exchange structure for enhanced heat exchange with the environment is selected from any one or a combination of the following: (1) The cylindrical wall of the cyclone separator is not provided with a heat insulation layer, so that the cylindrical wall directly dissipates heat to the ambient air; (2) The cylindrical wall of the cyclone separator is made of a material with a thermal conductivity higher than 200 W / (m·K); (3) The outer wall of the cyclone separator is provided with several heat dissipation fins to increase the heat dissipation area; (4) The outer wall of the cyclone separator is provided with a spirally wrapped cooling coil, and a cooling medium is introduced into the coil; (5) The outer wall of the cyclone separator is coated with a radiation heat dissipation coating.

[0009] In the above technical solution, preferably, it also includes a collection hopper, which is connected to the bottom of the gas-solid condensation enhanced separator and is used to collect condensate and captured wet solid materials; the bottom of the collection hopper is provided with a discharge valve.

[0010] In the above technical solution, a further preferred embodiment is that the control unit is also configured to: in non-winter working conditions, when it is necessary to clean the wet material accumulated in the collection hopper, execute a drying procedure, the drying procedure including: closing the discharge valve, introducing hot gas into the collection hopper to dry the wet material, and opening the discharge valve to discharge the dry material after drying is completed.

[0011] In the above technical solution, it is further preferred that the hot gas comes from any of the following sources: gas drawn from the top of the powder storage tank, hot air drawn from other high-temperature waste gas pipes in the system, hot air generated by the auxiliary heater, or outdoor air in summer.

[0012] The present invention also provides a method for preventing condensation in exhaust gas from a storage facility containing moist powder, comprising the following steps: Obtain the first dew point temperature Td1 of the exhaust gas discharged from the powder storage silo; The Td1 is compared with the real-time ambient temperature Tenv; when Td1>Tenv + ΔT1, the exhaust gas is introduced into the anti-condensation branch, so that the exhaust gas is cooled and condensed in the gas-solid condensation enhanced separator with a heat exchange structure that enhances heat exchange with the environment, thereby achieving gas-liquid separation; when Td1 ≤ Tenv + ΔT1, the exhaust gas is introduced into the non-condensation treatment branch, and discharged after dust collection. Obtain the second dew point temperature Td2 of the gas after condensation and separation, and dynamically adjust the system operating parameters according to Td2 to make Td2 ≤ Tenv + ΔT2; The dehydrated gas is discharged after dust collection.

[0013] In the above technical solution, preferably, it further includes: collecting the mixture of condensate and wet material obtained from the bottom of the gas-solid condensation enhanced separator; and, under non-winter conditions, passing hot gas through the collected mixture for drying treatment to recover the dried material.

[0014] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method.

[0015] Compared with the prior art, the present invention has the following significant advantages: This invention enables the dew point temperature of treated exhaust gas to drop to ambient temperature plus a temperature margin, completely eliminating localized condensation caused by pulse backflushing inside baghouse dust collectors. Specifically, this invention utilizes a gas-solid condensation enhanced separator with an enhanced heat exchange structure with the environment, installed in the anti-condensation branch. This actively leverages the natural cold source of low winter ambient temperatures, rapidly cooling the high-temperature, high-humidity exhaust gas to the Tenv+ΔT2 range within the gas-solid condensation enhanced separator. Water vapor condenses into liquid water and separates from the gas, thus completing the dehydration process before entering the dust collector. This technique ensures that the gas inside the dust collector maintains a low moisture content, with its dew point temperature dropping to near ambient temperature. The temperature difference between the dust collector and the ambient air is only ΔT2. According to common knowledge, the exhaust temperature of an air compressor (backflushing compressed air) is generally 3-10°C higher than Tenv. Therefore, when the backflushing compressed air enters the dust collector and comes into contact with the exhaust gas, a momentary low-temperature zone is not formed, and the temperature field does not change significantly. Water vapor will not condense, thus preventing dust caking and eliminating the need for a complex temperature control system. As a further advantage, the present invention eliminates the need for heat tracing, which can significantly reduce investment and energy consumption compared to traditional heat tracing solutions. It can also adapt to various low-temperature environments, solving the problem that traditional solutions cannot operate stably in frigid regions. Attached Figure Description

[0016] The technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless specifically indicated, these drawings are intended only to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0017] Figure 1 A schematic diagram of the anti-condensation treatment system provided in an embodiment of the present invention. Figure 1 ; Figure 2 A schematic diagram of the anti-condensation treatment system provided in an embodiment of the present invention. Figure 2 ; Figure 3 The graphs show the resistance-time relationship of the dust collectors in Embodiment 1 and Comparative Example 1 of the present invention.

[0018] In the diagram: 1-Powder storage silo; 2-Main processing pipeline; 3-Switching device; 4-Non-condensation processing branch; 5-Anti-condensation branch; 6-Gas-solid condensation enhanced separator; 7-Dust collector; 71-First dust collector; 72-Second dust collector; 8-Fan; 81-First fan; 82-Second fan; 9-Collection hopper; 10-First sensor; 11-Second sensor. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All equivalent substitutions or improvements made based on the above-described concepts of this invention should be included within the scope of protection of this invention.

[0020] Technical Implementation Idea of ​​the Invention The inventors of this invention discovered that traditional anti-condensation solutions for waste gas from powder storage silos generally focus on maintaining the temperature of the waste gas above its dew point throughout the transportation and treatment process through methods such as insulation or active heating. However, in-depth analysis revealed a fundamental limitation of this approach: it only focuses on controlling the macroscopic average temperature of the waste gas, completely ignoring the highly uneven and drastic temperature fluctuations within the bag filter caused by periodic pulse backflushing. Specifically, the instantaneous injection of low-temperature backflushing compressed air creates unpredictable and uncontrollable localized low-temperature zones on the filter bag surface, causing frequent condensation and re-evaporation of water vapor, accelerating dust caking, and increasing the resistance of the dust collector. This contradictory phenomenon of "global overheating - localized undercooling" not only cannot be eliminated but also exacerbates system energy consumption by attempting to increase the temperature of the main waste gas to compensate for localized temperature drops. This reveals a deep-seated flaw in the thermodynamic control principle of traditional solutions: attempting to use a single, lagging temperature control parameter to address a complex multiphase flow problem dominated by transient mass and heat transfer inevitably leads to a vicious cycle of high energy consumption and condensation risk.

[0021] Based on this understanding, the technical approach provided by this invention fundamentally changes the problem-solving path: abandoning the traditional mindset of "passive defense and striving to maintain temperature," it adopts a new strategy of "active guidance and pre-control." Its core lies in pre-setting a dedicated gas-solid condensation enhanced separation stage before the exhaust gas enters the dust collector. The core concept of this stage is to actively utilize the natural cold source of low winter ambient temperatures. By constructing the cylinder wall of the gas-solid condensation enhanced separator with a structure that enhances heat exchange with the environment, the high-temperature, high-humidity exhaust gas is rapidly cooled to below its dew point within the separator, thus allowing the water vapor to condense and separate before entering the main dust collector. This innovative technical approach ensures that the gas processed in the subsequent dust collector always maintains a low moisture content, and its dew point temperature is stabilized near the ambient temperature. In this way, even if the temperature of the backflushing compressed air is low, the temperature difference between it and the main exhaust gas is significantly reduced, fundamentally eliminating the thermodynamic conditions for condensation on the filter bag surface due to localized low-temperature zones. This method not only cleverly utilizes environmental cold sources to achieve zero-energy dehydration, but also transforms uncontrollable and harmful "condensation" into controllable and beneficial "condensation separation," thereby achieving a synergistic improvement in the energy efficiency and reliability of the waste gas treatment process.

[0022] like Figure 1 As shown, an embodiment of the present invention provides an anti-condensation treatment system for exhaust gas from a wet powder storage silo, including a powder storage silo 1, a main treatment pipeline 2, a switching device 3, a non-condensation treatment branch 4, an anti-condensation branch 5, a gas-solid condensation enhanced separator 6, a dust collector 7, a fan 8, a collection hopper 9, a first sensor 10, a second sensor 11, and a control unit.

[0023] The main processing pipeline 2 is connected to the top outlet of the powder storage silo 1 and is used to extract the humid, high-temperature waste gas generated in the powder storage silo 1 due to the evaporation of moisture from the materials. The powder materials (such as carbide slag, slag, fly ash, etc.) stored in the powder storage silo 1 usually carry residual moisture and are at a high temperature when they enter the silo. The moisture continues to evaporate in the silo, causing positive pressure to form inside the silo. It is necessary to discharge the waste gas through the top outlet to maintain a slight negative pressure inside the silo.

[0024] The switching device 3 is installed on the main processing pipeline 2 to receive the waste gas from the powder storage silo 1 and selectively distribute the waste gas to the non-condensation treatment branch 4 or the anti-condensation branch 5. The switching device 3 can be implemented using a three-way reversing valve, and the operation of the switching device 3 is controlled by the control unit based on the dew point temperature Td1 detected by the first sensor 10.

[0025] A gas-solid condensation enhanced separator 6 is installed along the airflow direction on the anti-condensation branch 5. The gas-solid condensation separator 6 is used to condense water vapor in the exhaust gas into liquid water and separate it from the gaseous exhaust gas before it enters the dust collector 7. The cylinder wall of the gas-solid condensation separator 6 is provided with a heat exchange structure to enhance heat exchange with the environment, so as to promote the dissipation of heat from the cylinder wall to the environment and enable the exhaust gas to cool down rapidly in the separator.

[0026] The non-condensing treatment branch 4 and the anti-condensation branch 5 are connected in parallel. The outlets of the non-condensing treatment branch 4 and the anti-condensation branch 5 can be merged and connected to the same dust collector 7, and the outlet of the dust collector 7 can be connected to the same fan 8; alternatively, they can be connected to their respective dust collectors and fans, i.e., the outlet of the non-condensing treatment branch 4 is sequentially connected to the first dust collector 71 and the first fan 81, and the outlet of the anti-condensation branch 5 is sequentially connected to the second dust collector 72 and the second fan 82. The dust collectors 7, 71, and 72 are preferably baghouse dust collectors, used to filter and purify the dust in the exhaust gas. The fans 8, 81, and 82 provide suction power for the entire system, maintaining a slight negative pressure state within the powder storage silo 1.

[0027] The first sensor 10 is installed on the main processing pipeline 2 upstream of the switching device 3 to obtain the first dew point temperature Td1 of the exhaust gas. The second sensor 11 is installed on the anti-condensation branch 5 at the outlet of the gas-solid condensation enhanced separator 6 to obtain the second dew point temperature Td2 of the gas after condensation and separation. The first sensor 10 and the second sensor 11 can be integrated temperature and humidity sensors, which can simultaneously measure temperature and relative humidity, and calculate the dew point temperature based on the temperature and humidity data through a built-in calculation unit or by the control unit.

[0028] The control unit is configured to perform the following operations: (a) The first dew point temperature Td1 is obtained through the first sensor 10; (b) When Td1>Tenv + ΔT1, the control switching device 3 directs the waste gas flow to the anti-condensation branch 5, and the waste gas passes through the gas-solid condensation enhanced separator 6; when Td1 ≤Tenv + ΔT1, the control switching device 3 directs the waste gas flow to the non-condensation treatment branch 4. (c) Obtain the second dew point temperature Td2 through the second sensor 11; (d) Dynamically adjust the fan air volume corresponding to the anti-condensation branch 5 so that Td2 ≤ Tenv + ΔT2; Where Tenv is the real-time ambient temperature, ΔT1 is the preset first temperature margin, and ΔT2 is the preset second temperature margin.

[0029] The control unit is preferably a programmable logic controller (PLC), which includes a processor module, an analog input module (for receiving signals from the first and second sensors), and an analog output module (for outputting control signals to the switching device and the air circuit regulating valve). The control unit stores the computer program of the above control logic.

[0030] During system operation, the high-temperature and high-humidity exhaust gas discharged from the top of powder storage silo 1 first reaches the first sensor 10 via the main treatment pipeline 2. The first sensor 11 detects the first dew point temperature Td1 of the exhaust gas in real time and transmits it to the control unit. The control unit compares Td1 with the real-time ambient temperature Tenv + ΔT1: When Td1 > Tenv + ΔT1, it indicates that there is a risk of condensation in the exhaust gas at the current ambient temperature. The control unit controls the switching device 3 to introduce the exhaust gas into the anti-condensation branch 5. The exhaust gas first enters the gas-solid condensation enhanced separator 6. In this separator, the high-temperature and high-humidity exhaust gas comes into full contact with the low-temperature wall surface that exchanges heat with the environment through the cylinder wall. The heat is dissipated to the environment through the cylinder wall, and the exhaust gas temperature drops rapidly. Water vapor condenses into tiny droplets. At the same time, under the centrifugal force of the separator, the condensed droplets and wet solid materials are thrown against the wall surface and fall down to the bottom for discharge. The dehydrated gas is discharged from the top outlet of the separator. After the second dew point temperature Td2 is detected by the second sensor 11, it enters the dust collector 7 for dust removal and is finally discharged by the fan 8. During this process, the control unit dynamically adjusts the air volume of the fan corresponding to the anti-condensation branch 5 based on the Td2 feedback from the second sensor 11, so as to adjust the residence time and cooling intensity of the exhaust gas in the separator, so that Td2 is always controlled below Tenv + ΔT2, ensuring that the gas entering the dust collector 7 has been fully dehydrated.

[0031] When Td1 ≤ Tenv + ΔT1, it indicates that there is no risk of condensation in the exhaust gas at the current ambient temperature. The control unit controls the switching device 3 to directly introduce the exhaust gas into the non-condensation treatment branch 4. After dust removal by the dust collector 7, it is discharged by the fan 8 without needing to undergo condensation treatment.

[0032] This invention achieves anti-condensation treatment of waste gas from storage tanks containing moist powder. Its core advantage lies in the fact that, before the waste gas enters the dust collector, a gas-solid condensation enhanced separator with an enhanced heat exchange structure actively utilizes the ambient cold source to pre-condense and separate water vapor, fundamentally eliminating the physical conditions for water vapor condensation within the subsequent dust collector. The dew point temperature of the gas after condensation and separation is significantly reduced. Even if the temperature of the compressed air used for pulse backflushing in the dust collector is low, the temperature difference between it and the main waste gas is greatly reduced, preventing localized condensation on the filter bag surface. Compared to traditional heat tracing solutions, this invention eliminates the need for heat tracing energy, significantly reducing operating energy consumption. Furthermore, it can adapt to various low-temperature environments, solving the problem of traditional solutions failing to operate stably in extremely cold regions.

[0033] In a preferred embodiment, the values ​​of ΔT1 and ΔT2 range from 0 to 10°C. In this invention, the values ​​of the temperature margins ΔT1 and ΔT2 are not fixed but can be adaptively adjusted according to the actual application scenario.

[0034] The purpose of setting ΔT1 and ΔT2 is to offset the local temperature drop introduced by the backflushing compressed air of the dust collector, ensuring that the internal operating conditions of the dust collector will not reach condensation conditions under the backflushing action. The selection of ΔT1 and ΔT2 is mainly based on the difference between the actual temperature of the backflushing compressed air and the real-time ambient temperature Tenv; in engineering, the temperature of the backflushing compressed air is usually 3–10℃ higher than the ambient temperature. The values ​​of ΔT1 and ΔT2 are respectively within the range of 0–10℃. A larger temperature margin should be selected for extremely cold and low-temperature conditions, while for non-winter conditions, the values ​​can be selected as needed within the range of 0–10℃.

[0035] The heat exchange structure for enhanced heat exchange with the environment can be a combination of any one or more of the following methods: (1) The cylindrical wall of the cyclone separator is not provided with a heat insulation layer: the cylindrical wall is directly exposed to the ambient air, and the heat is dissipated to the environment through natural convection and radiation of the wall. This is the simplest and lowest cost way to enhance heat exchange. (2) The cylindrical wall of the cyclone separator is made of a material with high thermal conductivity, such as aluminum alloy, copper alloy, galvanized plate, etc., with a thermal conductivity higher than 200 W / (m·K), in order to improve the heat conduction efficiency from the inner wall of the cylinder to the outer wall and accelerate heat dissipation from the wall. (3) The outer wall of the cyclone separator is provided with several heat dissipation fins: the fins arranged along the axial or circumferential direction of the cylinder can significantly increase the heat dissipation area, improve the convective heat transfer coefficient, and enhance the heat dissipation of the wall to the environment. (4) The outer wall of the cyclone separator is provided with a spirally wrapped cooling coil: a cooling medium (such as ambient air or cooling water) is introduced into the coil to actively enhance heat exchange, which is suitable for handling conditions with large air volume and high exhaust gas temperature. (5) The outer wall of the cyclone separator is coated with a radiation heat dissipation coating: the heat dissipation effect of the wall is enhanced by radiation heat exchange, especially at night or in clear weather.

[0036] The above options can be combined and selected based on the actual working conditions, such as ambient temperature, exhaust gas moisture content, and treatment air volume.

[0037] In a preferred embodiment, the system further includes a collection hopper 9, which is connected to the bottom of the gas-solid condensation enhanced separator 6 and is used to collect condensate and captured wet solid materials. A discharge valve is provided at the bottom of the collection hopper 9. The collection hopper 9 is located directly below the gas-solid condensation enhanced separator 6 and has a conical structure that is wider at the top and narrower at the bottom, facilitating material collection and discharge. The condensate (liquid water) separated in the gas-solid condensation enhanced separator 6 and the captured wet solid materials (including wet dust) fall into the collection hopper 9 under gravity for temporary storage. The discharge valve at the bottom of the collection hopper 9 is opened when needed to discharge the collected material.

[0038] In a preferred embodiment, the control unit is further configured to: in non-winter working conditions, when it is necessary to clean the wet material accumulated in the collection hopper 9, execute a drying procedure, the drying procedure including: closing the discharge valve, introducing hot gas into the collection hopper 9 to dry the wet material, and opening the discharge valve to discharge the dry material after drying is completed.

[0039] The material collected in hopper 9 is a mixture of condensate and wet solid material with a high moisture content. Direct discharge could cause secondary pollution or material waste. Therefore, this invention incorporates a drying program in the control unit. During the drying process, the control unit first closes the discharge valve and then introduces hot gas into hopper 9. The hot gas passes through the wet material layer, heating and drying the material, evaporating and carrying away the moisture. Once drying is complete, the control unit opens the discharge valve to discharge the dried material, achieving material recovery.

[0040] The non-winter working condition described in this invention refers to a working condition where the real-time ambient temperature Tenv is higher than the set low temperature threshold (e.g., 0°C). When the ambient temperature is very low (severe winter), the condensed material in the hopper is very easy to freeze, so the drying process is not performed to avoid the risk of freezing and blockage.

[0041] In a preferred embodiment, the hot gas comes from any of the following sources: gas drawn from the top of the powder storage silo 1, hot air drawn from other high-temperature waste gas pipes within the system, hot air generated by the auxiliary heater, or outdoor air during summer. The source of the hot gas can be flexibly selected according to site conditions to maximize the utilization of existing heat sources and reduce energy consumption.

[0042] This embodiment also provides a method for preventing condensation in exhaust gas from a storage silo containing moist powder, comprising the following steps: Step S1: Obtain the first dew point temperature Td1 of the exhaust gas discharged from the powder storage silo. The temperature and relative humidity of the exhaust gas discharged from the top of the powder storage tank 1 are monitored in real time by a first sensor 10 installed on the main processing pipeline 2 and upstream of the switching device 3, and the first dew point temperature Td1 is calculated. The first sensor 10 transmits the Td1 signal to the control unit in real time.

[0043] Step S2: Compare Td1 with the real-time ambient temperature Tenv. After receiving the Td1 signal, the control unit compares it with the real-time ambient temperature Tenv. Based on the comparison result, it determines the exhaust gas treatment path. When Td1 > Tenv + ΔT1 (where ΔT1 is the first temperature margin), it indicates that there is a risk of condensation in the exhaust gas at the current ambient temperature. The control unit controls the switching device 3 to introduce the exhaust gas into the anti-condensation branch 5. After the exhaust gas enters the gas-solid condensation enhanced separator 6, the high-temperature and high-humidity exhaust gas comes into full contact with the low-temperature wall surface that exchanges heat with the environment through the cylinder wall. The heat is dissipated to the environment through the heat exchange structure set on the cylinder wall to enhance heat exchange with the environment, and the exhaust gas temperature drops rapidly, and the water vapor condenses into liquid water. At the same time, under the action of centrifugal force of the separator, the condensed droplets and wet solid materials are thrown towards the wall surface and fall down the wall surface to the bottom for discharge. The dehydrated gas is discharged from the top outlet of the separator.

[0044] When Td1 ≤ Tenv + ΔT1, it indicates that there is no risk of condensation or the risk of condensation in the exhaust gas at the current ambient temperature. The control unit controls the switching device 3 to introduce the exhaust gas into the non-condensation treatment branch 4, and after dust removal by the dust collector 7, it is discharged by the fan 8.

[0045] Step S3: Obtain the second dew point temperature Td2 of the gas after condensation and separation, and dynamically adjust the fan volume corresponding to the anti-condensation branch according to Td2, so that Td2 ≤ Tenv + ΔT2 The second sensor 12, installed at the outlet of the gas-solid condensation enhanced separator 6, monitors the second dew point temperature Td2 of the gas after condensation separation in real time and transmits the signal to the control unit. The control unit uses the deviation between the measured value of Td2 and the target value (Tenv + ΔT2) as input, and outputs an adjustment signal to control the airflow of the fan corresponding to the anti-condensation branch, dynamically adjusting the residence time and cooling intensity of the exhaust gas in the gas-solid condensation enhanced separator. When Td2 > Tenv + ΔT2 (where ΔT2 is the second temperature margin), it indicates that condensation is insufficient. The control unit reduces the fan airflow to increase the residence time of the exhaust gas in the separator and enhance the condensation effect.

[0046] When Td2 is near the target value, keep the current running parameters unchanged.

[0047] Step S4: The dehydrated gas is discharged after dust collection. The exhaust gas, after being fully dehydrated by condensation and separation, enters the dust collector 7 for dust removal. The purified gas is then discharged to the atmosphere by the fan 8. Because the gas entering the dust collector 7 has been fully dehydrated, its dew point temperature is significantly reduced (Td2 ≤ Tenv + ΔT2). Even though the temperature of the pulse backflushing compressed air is low, local condensation cannot form on the surface of the filter bags, thus completely eliminating the hidden danger of condensation and caking in the dust collector.

[0048] In a preferred embodiment, the method further includes: collecting a mixture of condensate and wet material obtained from the bottom of the gas-solid condensation enhanced separator 6; and, under non-winter conditions, passing hot gas through the collected mixture for drying to recover the dried material.

[0049] The mixture of condensate and wet material discharged from the bottom of the gas-solid condensation enhanced separator 6 falls into the collection hopper 9 for temporary storage. In non-winter operating conditions, when the material in the collection hopper 9 accumulates to a certain amount and needs to be cleaned, the control unit executes a drying procedure: closing the discharge valve, introducing hot gas into the collection hopper 9 to dry the wet material, and opening the discharge valve after drying to discharge the dry material, thus achieving material recycling. The source of the hot gas can be flexibly selected according to site conditions, including gas drawn from the top of the powder storage silo 1, hot air drawn from other high-temperature waste gas pipelines in the system, hot air generated by the auxiliary heater, or outdoor air in summer.

[0050] To verify the technical effectiveness of the anti-condensation treatment system described in this invention, a continuous experiment lasting 30 calendar days was conducted. All tests were carried out under the same experimental conditions to ensure comparability of results. The test subject was the exhaust gas treatment system of a dry powder storage silo for calcium carbide slag in a chemical plant in a certain city. The exhaust gas temperature was 100~120℃, the moisture content was 1~5%, and the treatment air volume was 6000m³. 3 / h. The outdoor design temperature for ventilation in this area during winter is -17.0℃, and the outdoor design temperature for heating is -24.0℃. The daily coldest temperature during the experiment ranges from -24℃ to -20℃, and -24℃ is taken. The gas-solid condensation enhanced separator is a cyclone separator made of galvanized sheet metal, and its cylinder wall is constructed with metal fins to enhance heat exchange with the environment, thereby promoting condensation.

[0051] Experimental conditions The exhaust gas temperature was measured using a type K thermocouple, and the moisture content was monitored online using a high-temperature humidity sensor. The dew point temperature was calculated based on the temperature and humidity data. The resistance of the baghouse dust collector was measured using a differential pressure transmitter. The main evaluation indicators included: baghouse dust collector resistance (Pa) and adaptability to extreme low-temperature conditions (operating time). The experiment lasted 720 hours.

[0052] Data Processing and Formulas The resistance of a baghouse dust collector = inlet pressure of the baghouse dust collector - outlet pressure of the baghouse dust collector Extreme low-temperature operating condition adaptability (operating time) is quantified as "the cumulative number of hours in which the resistance of the bag filter remains continuously less than 2500 Pa". This threshold (2500 Pa) is set based on engineering practice and can effectively distinguish between normal and abnormal operating states of the system, thereby accurately measuring the long-term operational reliability of the system in extreme environments.

[0053] Example 1 (Invention) System Configuration: The anti-condensation treatment system described in this invention includes a main treatment pipeline 2, a non-condensation treatment branch 4, an anti-condensation branch 5, a switching device 3, a gas-solid condensation enhanced separator 6, a dust collector 7, a fan 8, and a control unit. The gas-solid condensation enhanced separator 6 is a cyclone separator made of galvanized steel, and its outer wall is provided with axially extending metal heat dissipation fins. The control unit automatically switches the airflow path and adjusts the corresponding fan airflow based on the dew point temperature monitored by the first sensor 10 and the second sensor 11, so that the dew point temperature Td2 at the outlet of the anti-condensation branch 5 ≤ Tenv + ΔT2.

[0054] Operating parameters: Exhaust gas is drawn from the top of powder storage silo 1 and enters the system via main treatment pipeline 2. When the dew point temperature Td1 of the main treatment pipeline > ambient temperature Tenv + ΔT1, the switching device 3 opens the anti-condensation branch 5, and the exhaust gas flows sequentially through the gas-solid condensation enhanced separator 6, dust collector 7, and fan 8 before being discharged; when Td1 ≤ Tenv + ΔT1, the switching device 3 opens the non-condensation treatment branch 4, and the exhaust gas directly passes through dust collector 7 and fan 8 before being discharged. Condensate and wet materials collected in the collection hopper 9 are discharged periodically.

[0055] Tenv is set to -24℃, ΔT1 and ΔT2 are set to 5℃, and the actual measured Td1 is 8℃. The anti-condensation branch 5 is turned on throughout the process, and Td2 is controlled to ≤ -24+5 =-19℃.

[0056] Comparative Example 1 (Traditional Solution) System configuration: The traditional electric heat tracing and insulation scheme is adopted. Electric heat tracing tape and insulation layer are installed on the conveying pipeline from the powder storage silo to the bag dust collector and on the outside of the dust collector body. The temperature controller maintains the temperature of the pipeline and dust collector wall above 80°C to prevent the exhaust gas temperature from dropping below the dew point.

[0057] Operating parameters: Exhaust gas is drawn from the top of the powder storage silo, transported to a bag filter via a heated and insulated pipeline, and discharged by a fan after dust removal. The electric heating system automatically starts and stops based on the pipeline temperature to maintain a stable system temperature.

[0058] Data Comparison The dust collector resistance-time relationship curves of Example 1 and Comparative Example 1 are as follows: Figure 3 As shown.

[0059] According to the resistance-time relationship curves shown, under the same extreme low temperature (-24℃) environment and high humidity exhaust gas conditions, Example 1 and Comparative Example 1 exhibit significantly different long-term operating performance.

[0060] In Example 1 (the system of this invention), during the entire 720-hour test cycle, the resistance of its baghouse dust collector steadily and slowly increased from an initial resistance of approximately 600 Pa to approximately 950 Pa at the end of the test, with the resistance growth curve being approximately linear. Its resistance remained well below the engineering safety threshold of 2500 Pa throughout the entire test, and continuously met the extreme working condition adaptability criterion of "resistance continuously remaining below 2500 Pa" for the entire working time. Extrapolating from its linear growth trend (approximately 0.5 Pa / hour), the theoretical operating time to reach a resistance of 2500 Pa could exceed 3800 hours (approximately 5.3 months). Considering the length of winter in the city (approximately 5 months), this system, without any maintenance or cleaning, possesses the ability to independently support continuous and stable operation throughout the entire winter's extreme low temperatures, fundamentally meeting the industrial needs for continuous and safe production of powder storage facilities during winter.

[0061] The resistance growth of Comparative Example 1 (a conventional electric heat tracing system) shows a completely different trend. Its resistance rises rapidly in the initial stage, reaching and exceeding 2500 Pa around 600 hours of operation. Afterward, the resistance curve enters a high plateau period close to 2500 Pa, indicating that the system has essentially failed due to severe condensation and cannot maintain normal operation by relying on heat tracing. Therefore, its cumulative operating time meeting the requirement of "resistance continuously remaining below 2500 Pa" is only about 600 hours. Since the power of the fan is determined by both the air volume and its resistance, under the same air volume, the resistance of Comparative Example 1 is much greater than that of Example 1. Therefore, the energy consumption of the system of the present invention is lower than that of the conventional solution.

[0062] Mechanism Analysis and Technical Effects The above significant performance comparison profoundly reveals the essential differences between the two technical approaches in their fundamental mechanisms for preventing condensation.

[0063] The passive insulation and active heating strategy used in Comparative Example 1 (traditional solution) cannot eliminate the localized instantaneous low temperature zone inside the bag filter caused by periodic pulse backflushing. In this "thermodynamic trap", water vapor repeatedly condenses and evaporates, causing dust to clump together, the air permeability of the filter bag deteriorates sharply, and the system resistance therefore soars exponentially, quickly reaching the operational safety threshold.

[0064] In stark contrast, Example 1 (the present invention) shifts the core logic of condensation prevention from "blocking" to "guiding" through a pre-positioned gas-solid condensation enhanced separator and intelligent switching control. Before the exhaust gas enters the baghouse dust collector, the system actively utilizes the ambient cold source, employing a gas-solid condensation enhanced separator with an enhanced heat exchange structure with the environment to rapidly cool the high-temperature, high-humidity exhaust gas under controlled conditions, completing the condensation and separation of water vapor. This eliminates the possibility of condensation occurring in subsequent equipment at the source. This ensures that the exhaust gas entering the baghouse dust collector remains in a "dry" state, and even in extremely cold environments of -24°C, pulse backflushing will not cause localized condensation. Therefore, its system resistance only increases slowly, demonstrating excellent long-term operational stability and adaptability to extreme environments.

[0065] The above embodiments have provided a detailed description of the present invention, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made in accordance with the present invention should still fall within the scope of the present invention.

Claims

1. A condensation prevention system for waste gas from a storage silo containing moist powder, characterized in that, include: The main processing pipeline is connected to the top outlet of the powder storage silo; A switching device is installed on the main processing pipeline to receive waste gas from the powder storage tank and selectively distribute the waste gas to a non-condensation treatment branch or an anti-condensation branch. An anti-condensation branch is provided, along which a gas-solid condensation enhanced separator is installed. The gas-solid condensation enhanced separator is used to condense the water vapor in the waste gas into liquid water before it enters the dust collector and separate it from the gaseous waste gas. The cylindrical wall of the gas-solid condensation enhanced separator is provided with a heat exchange structure to enhance heat exchange with the environment. The non-condensing treatment branch and the anti-condensation branch are set in parallel. The outlets of both the non-condensing treatment branch and the anti-condensation branch are connected to a dust collector, and the outlet of the dust collector is connected to a fan. The first sensor is installed on the main processing pipeline upstream of the switching device to obtain the first dew point temperature Td1 of the exhaust gas. The second sensor is installed on the anti-condensation branch at the outlet of the gas-solid condensation enhanced separator to obtain the second dew point temperature Td2 of the gas after condensation and separation. The control unit is configured to perform the following operations: The first dew point temperature Td1 is obtained through the first sensor; when Td1>Tenv + ΔT1, the switching device is controlled to direct the waste gas flow to the anti-condensation branch and flow through the gas-solid condensation enhanced separator; when Td1≤Tenv + ΔT1, the switching device is controlled to direct the waste gas flow to the non-condensation treatment branch. The second dew point temperature Td2 is obtained through the second sensor; the air volume of the fan corresponding to the anti-condensation branch is dynamically adjusted so that Td2 ≤ Tenv + ΔT2; Where Tenv is the real-time ambient temperature, ΔT1 is the preset first temperature margin, and ΔT2 is the preset second temperature margin.

2. The anti-condensation treatment system for waste gas from a storage silo containing moist powder according to claim 1, characterized in that, The values ​​of ΔT1 and ΔT2 are respectively in the range of 0~10℃.

3. The anti-condensation treatment system for waste gas from a storage silo containing moist powder according to claim 1, characterized in that, The gas-solid condensation enhanced separator is a cyclone separator.

4. The anti-condensation treatment system for waste gas from a storage silo containing moist powder according to claim 3, characterized in that, The heat exchange structure for enhanced heat exchange with the environment is selected from any one or a combination of the following: (1) The cylindrical wall of the cyclone separator is not provided with a heat insulation layer, so that the cylindrical wall directly dissipates heat to the ambient air; (2) The cylindrical wall of the cyclone separator is made of a material with a thermal conductivity higher than 200 W / (m·K); (3) The outer wall of the cyclone separator is provided with several heat dissipation fins to increase the heat dissipation area; (4) The outer wall of the cyclone separator is provided with a spirally wound cooling coil, and a cooling medium is introduced into the coil; (5) The outer wall of the cyclone separator is coated with a radiation heat dissipation coating.

5. The anti-condensation treatment system for waste gas from a storage silo containing moist powder according to claim 1, characterized in that, It also includes a collection hopper, which is connected to the bottom of the gas-solid condensation enhanced separator and is used to collect condensate and captured wet solid materials; the bottom of the collection hopper is provided with a discharge valve.

6. The anti-condensation treatment system for waste gas from a storage silo containing moist powder according to claim 5, characterized in that, The control unit is also configured to: in non-winter operating conditions, when it is necessary to clean the wet material accumulated in the collection hopper, execute a drying procedure, the drying procedure including: closing the discharge valve, introducing hot gas into the collection hopper to dry the wet material, and opening the discharge valve to discharge the dry material after drying is completed.

7. The anti-condensation treatment system for waste gas from a storage silo containing moist powder according to claim 6, characterized in that, The hot gas comes from any of the following sources: gas drawn from the top of the powder storage tank, hot air drawn from other high-temperature waste gas pipes in the system, hot air generated by the auxiliary heater, or outdoor air in summer.

8. A method for preventing condensation in waste gas from a storage silo containing moist powder, characterized in that, Includes the following steps: Obtain the first dew point temperature Td1 of the exhaust gas discharged from the powder storage silo; The Td1 is compared with the real-time ambient temperature Tenv; when Td1>Tenv + ΔT1, the exhaust gas is introduced into the anti-condensation branch, so that the exhaust gas is cooled and condensed in the gas-solid condensation enhanced separator with a heat exchange structure that enhances heat exchange with the environment, thereby achieving gas-liquid separation; when Td1 ≤ Tenv + ΔT1, the exhaust gas is introduced into the non-condensation treatment branch, and discharged after dust collection. Obtain the second dew point temperature Td2 of the gas after condensation and separation, and dynamically adjust the system operating parameters according to Td2 to make Td2 ≤ Tenv + ΔT2; The dehydrated gas is discharged after dust collection.

9. The method for preventing condensation in waste gas from a storage silo containing moist powder, as described in claim 8, is characterized in that... It also includes: collecting the mixture of condensate and wet material obtained from the bottom of the gas-solid condensation enhanced separator; and, under non-winter conditions, passing hot gas through the collected mixture for drying and recovering the dried material.

10. A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method as claimed in claim 8 or 9.

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