A device and method for atomizing and wetting tar-containing fly ash from biomass gasification

Abstract

This invention belongs to the field of fly ash treatment technology, specifically disclosing an atomizing and wetting device and method for biomass gasification tar-containing fly ash. The device includes a water tank, a reagent supply system, a humidifying and stirring mechanism, an atomizing spraying mechanism, and a fly ash feeder. The reagent supply system is used to add surfactants and defoamers to the water tank. The atomizing spraying mechanism includes a humidifying pump and multiple atomizing nozzles, which are disposed within the housing of the humidifying and stirring mechanism and arranged in segments along the axial direction of the spiral conveying mechanism. This invention achieves rapid wetting of fly ash by adding surfactants to demineralized water; simultaneously, the multi-row atomizing nozzles arranged in segments along the axial direction of the humidifying and stirring mechanism enable multi-point, diffuse humidification of the fly ash, and combined with forced stirring and conveying by the spiral conveying mechanism, allow the droplets and fly ash to fully and uniformly contact and mix, achieving a stable fly ash wetting effect.

Description

Technical Field

[0001] This invention relates to the field of fly ash treatment technology, specifically to an atomization and wetting device and method for biomass gasification tar-containing fly ash. Background Technology

[0002] Biomass gasification technology is a clean energy utilization process that converts biomass into combustible gas under oxygen-deficient conditions. In this gasification process, in addition to the target product, combustible gas, a certain amount of byproduct, fly ash, is also generated. Fly ash has a complex composition, mainly consisting of incompletely gasified residual carbon, the ash content of the biomass fuel itself (rich in alkali metals, chlorine, and other elements), and tar generated during gasification and condensed and adsorbed onto the surface of the fly ash particles. To prevent fly ash dust and facilitate subsequent transportation, storage, or disposal, the fly ash usually needs to be moistened to become appropriately humidified wet ash.

[0003] Currently, the main methods for wetting fly ash include direct spraying and immersion. Spraying involves installing nozzles above the fly ash conveying mechanism to spray clean water or coarse water mist directly onto the conveyed fly ash layer. Immersion involves directly pouring the collected fly ash into a water tank or a specific wet mixing device, mixing the fly ash with water through soaking and mechanical stirring. However, the presence of tar makes the surface of fly ash particles hydrophobic and highly adhesive, making it difficult for conventional spraying methods to achieve rapid penetration and wetting of tar-containing fly ash. Wetting treatment requires a long time; uneven wetting can easily lead to localized dust generation or over-wetting. Direct immersion methods, on the other hand, easily generate liquid wastewater, increasing the burden on subsequent water treatment. Furthermore, the specific composition of different batches of fly ash (such as tar content, residual carbon ratio, ash composition, etc.) fluctuates with changes in upstream gasification feedstock, gasifier operating temperature, oxygen ratio, and other operating parameters, further increasing the difficulty of stable fly ash wetting.

[0004] In view of this, the present application aims to provide an apparatus and method for rapidly, uniformly and stably wetting tar-containing fly ash, so that the treated wet ash can maintain a suitable humidity (such as a moisture content of 15% to 30%, with neither dust nor liquid water precipitation), so as to facilitate subsequent processing. Summary of the Invention

[0005] The purpose of this invention is to address at least one deficiency in the prior art by providing an atomization wetting device and method for biomass gasification tar-containing fly ash; achieving rapid and uniform wetting of fly ash during the transportation process, ultimately obtaining wet ash with stable humidity, no dust, and no wastewater.

[0006] To achieve the above objectives, the present invention provides a device for atomizing and wetting tar-containing fly ash from biomass gasification, comprising: Water tanks are used for storing and mixing solutions; A pharmaceutical supply system, connected to the water tank, is used to add surfactants and defoamers to the water tank; The humidifying and stirring mechanism includes a housing, a screw conveying mechanism disposed within the housing, and a drive motor for driving the screw conveying mechanism. The housing is provided with an inlet and an outlet. The atomizing spraying mechanism includes a humidifying pump and multiple atomizing nozzles connected to the humidifying pump via pipelines. The inlet of the humidifying pump is connected to the water tank. The atomizing nozzles are disposed inside the housing of the humidifying and stirring mechanism and are arranged in segments along the axial direction of the spiral conveying mechanism to atomize the solution in the water tank and spray it into the housing. The fly ash feeder has its outlet connected to the inlet of the humidifying and mixing mechanism, and is used to transport the tar-containing dry fly ash in the ash silo to the inlet of the humidifying and mixing mechanism.

[0007] Furthermore, the reagent supply system includes a surfactant storage tank for storing surfactants, a defoamer storage tank for storing defoamers, and a metering pump. The metering pump is used to pump the surfactants and defoamers into the water tank in a set ratio, so that the mass concentration of surfactants in the water tank solution is 10-500 ppm. Too low a concentration will not reduce the surface tension of tar, while too high a concentration will easily cause foam to be generated in the sprayed water.

[0008] Furthermore, the defoamer concentration is 5-50 ppm. Adding a defoamer can inhibit the foaming properties of surfactants, allowing the surfactants in the demineralized water to fully contact and wet the dry ash, while preventing surfactant foaming from carrying dry ash out into the environment.

[0009] Furthermore, the surfactant is a compound of nonionic surfactant and anionic surfactant in a mass ratio of 1:4 to 4:1.

[0010] Furthermore, the nonionic surfactant is any one of alkylphenol polyoxyethylene ether or fatty alcohol polyoxyethylene ether; the anionic surfactant is any one of sodium dodecylbenzene sulfonate or sodium olefin sulfonate; and the defoamer is an organosilicon defoamer.

[0011] Furthermore, a spray valve is installed on the pipeline between the atomizing nozzle and the outlet of the humidifying pump, and a circulation branch is provided between the outlet of the humidifying pump and the water tank, with a circulation valve installed on the circulation branch.

[0012] Furthermore, the atomizing nozzle is a nozzle that produces droplets with a particle size of 30-100μm; for example, an ultrasonic atomizing nozzle is used.

[0013] Furthermore, the screw conveyor mechanism can be any one of a single-axis screw, a double-axis screw, or a shaftless screw structure.

[0014] Furthermore, the outlet of the humidifying and mixing mechanism is equipped with a baffle or designed with an inclined angle to ensure that the solution sprayed into the bottom of the humidifying and mixing mechanism housing has sufficient contact time with the dry fly ash.

[0015] Furthermore, it also includes a control unit, which is signal-connected to the fly ash feeder, the metering pump in the reagent supply system, the humidifying pump in the atomizing spraying mechanism, and the drive motor in the humidifying and stirring mechanism. The control unit is used to control the working status of the metering pump, the humidifying pump, and the drive motor in conjunction with the feed rate of the fly ash feeder to achieve stable wetting of the fly ash.

[0016] Furthermore, the pharmaceutical supply system has multiple surfactant storage tanks, each storing different types of surfactants. When in use, surfactants from different storage tanks are selected on-site based on the fly ash composition test results to form compound surfactants.

[0017] Furthermore, a humidity sensor can be installed in the humidifying and mixing mechanism to provide real-time feedback on the humidity of the fly ash and adjust the spray volume of the atomizing nozzles accordingly. A corresponding concentration detector can also be installed in the water tank to monitor the concentration of defoamer and surfactants.

[0018] The present invention also provides a method for atomizing and wetting tar-containing fly ash from biomass gasification based on the above-mentioned apparatus, which includes the following steps: S1: Add demineralized water to the water tank. Based on the component detection results of the fly ash to be treated, use a metering pump to deliver surfactant and defoamer to the water tank in a preset ratio. Control the mass concentration of surfactant in the demineralized water solution in the water tank to be within the range of 10-500ppm and the mass concentration of defoamer to be within the range of 5-50ppm.

[0019] Generally, when the tar content in fly ash is high, the concentration of surfactants and defoamers in the solution in the tank is relatively high; conversely, when the tar content in fly ash is low, the concentration of surfactants and defoamers is relatively low. Simultaneously, a compound system of nonionic and anionic surfactants can be used. When preparing the surfactants, the nonionic and anionic surfactants can be mixed in a mass ratio between 1:4 and 4:1, depending on the characteristics of the fly ash components. That is, by adjusting the ratio of nonionic to anionic surfactants, the complementarity of tar molecules with different polarities and lipophilic molecules is achieved, enhancing the penetration and dispersion ability of the compound surfactant on complex tar structures.

[0020] S2: Close the spray valve, open the circulation valve, and start the humidification pump to allow the surfactant and defoamer added to the water tank to be quickly and evenly mixed through the circulation branch.

[0021] S3: After the solution is thoroughly mixed, open the spray valve and close the circulation valve. The mixed solution is then transported through the pipeline to the atomizing nozzle, where it is atomized into droplets with a particle size of 30-100μm and sprayed out in segments along the axial direction of the humidifying and mixing mechanism. Simultaneously, the dry fly ash containing tar in the ash silo is transported to the inlet of the humidifying and mixing mechanism via the fly ash feeder. The drive motor of the screw conveyor is started, causing the screw conveyor to forcibly stir the fly ash while transporting it, ensuring that the fly ash and droplets are fully contacted and mixed. The residence time of the fly ash in the humidifying mixer is controlled to be 10-60 seconds, and the moisture content is controlled to be 15-30%. S4: The wet ash after wetting and mixing is discharged from the outlet of the humidifying and mixing mechanism.

[0022] Furthermore, in step S3, the rotational speed of the drive motor, the flow rate and flow rate of the atomizing nozzle in the screw conveyor mechanism are all linked with the real-time feed rate of the fly ash feeder, so that the fly ash feed rate matches the solution spray rate and has sufficient contact mixing time, thereby achieving a stable wetting effect.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention adds a specific ratio of compound surfactant to the desalination water, enabling the desalination water to quickly penetrate and encapsulate the hydrophobic tar-containing fly ash particles, reducing the wetting angle of the tar surface from greater than 90° to below 30°, thus achieving second-level rapid wetting of fly ash. At the same time, the added defoamer effectively suppresses the foam generated by the surfactant, avoiding fly ash overflow caused by foam carrying, and ensuring the high efficiency and cleanliness of the wetting process; (2) This invention employs multiple rows of atomizing nozzles arranged in segments along the axial direction of the humidifying and stirring mechanism, which can uniformly atomize the mixed solution into fine droplets of 30-100μm, realizing multi-point, diffuse humidification of fly ash. Combined with a spiral conveying mechanism for forced stirring and conveying, the droplets and fly ash can fully and uniformly contact and mix, resulting in high wetting uniformity; (3) In view of the characteristic that the composition of biomass gasification fly ash fluctuates with the upstream operating conditions, the present invention can quickly configure and adjust the concentration of surfactant and defoamer according to the detection results of the current batch of fly ash composition, so that the mixed solution in the water tank can better wet the current batch of fly ash; the present invention also controls the feed rate of fly ash feeder, the flow rate of humidification pump and the rotation speed of screw conveyor through the control unit. For example, when the fly ash feed rate is detected to increase, the water volume can be increased by synchronously increasing the flow rate of atomizing nozzle, or the fly ash transmission speed can be slowed down to increase the contact time between fly ash and corresponding solution, so as to ensure that the moisture content of wet ash can be stably controlled within the target range (e.g., 15-30%). (4) The wetting device in this invention has a simple structure, is easy to modify and upgrade on the existing fly ash conveying system, has low cost and is easy to use. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the device in an embodiment of the present invention; In the diagram: 1. Water tank; 2. Fly ash feeder; 3. Humidifying and mixing mechanism; 4. Atomizing nozzle; 5. Humidifying pump; 6. Spraying valve; 7. Circulation valve; 8. Defoamer storage tank; 9. Surfactant storage tank; 10. Metering pump. Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided. Example

[0026] like Figure 1 As shown, this embodiment provides an atomizing and wetting device for biomass gasification tar-containing fly ash, comprising: a water tank 1 for storing and mixing solutions; a reagent supply system connected to the water tank 1 for adding surfactants and defoamers to the water tank 1; a humidifying and stirring mechanism 3, including a housing, a spiral conveying mechanism disposed within the housing, and a drive motor for driving the spiral conveying mechanism, the housing having an inlet and an outlet; an atomizing and spraying mechanism, including a humidifying pump 5 and multiple atomizing nozzles 4 connected to the humidifying pump 5 via pipelines, the inlet of the humidifying pump 5 being connected to the water tank 1; the atomizing nozzles 4 being disposed within the housing of the humidifying and stirring mechanism 3 and arranged in segments along the axial direction of the spiral conveying mechanism for atomizing and spraying the solution in the water tank 1 into the housing; and a fly ash feeder 2, the outlet of which is connected to the inlet of the humidifying and stirring mechanism 3 for conveying tar-containing dry fly ash from the ash silo to the inlet of the humidifying and stirring mechanism 3.

[0027] In this embodiment, the reagent supply system includes a surfactant storage tank 9 for storing surfactants, a defoamer storage tank 8 for storing defoamers, and two metering pumps 10. The two metering pumps 10 are used to pump the surfactants and defoamers into the water tank 1 in a set ratio, so that the concentration of surfactants in the solution of water tank 1 is 10-500 ppm and the concentration of defoamers is 5-50 ppm.

[0028] In this embodiment, the surfactant is a mixture of a nonionic surfactant and anionic surfactant in a mass ratio of 1:4 to 4:1. The nonionic surfactant is any one of alkylphenol polyoxyethylene ether or fatty alcohol polyoxyethylene ether; the anionic surfactant is any one of sodium dodecylbenzene sulfonate or sodium olefin sulfonate; and the defoamer is an organosilicon defoamer.

[0029] In this embodiment, a spray valve 6 is provided on the pipeline between the atomizing nozzle 4 and the outlet of the humidifying pump 5, and a circulation branch is provided between the outlet of the humidifying pump 5 and the water tank 1, and a circulation valve 7 is provided on the circulation branch.

[0030] In this embodiment, the atomizing nozzle 4 is an ultrasonic atomizing nozzle 4 that produces particles with a diameter of 30-100μm. The spiral conveying mechanism adopts a single-axis spiral structure.

[0031] In this embodiment, a baffle is provided at the outlet of the humidifying and stirring mechanism 3 to ensure that the solution sprayed into the humidifying and stirring mechanism 3 has sufficient contact time with the dry fly ash, so as to ensure moisture content control.

[0032] In this embodiment, the atomizing and wetting device also includes a control unit. The control unit is signal-connected to the fly ash feeder 2, the metering pump 10 in the reagent supply system, the humidifying pump 5 in the atomizing spraying mechanism, and the drive motor in the humidifying and stirring mechanism 3. It is used to control the working state of the corresponding metering pump 10, humidifying pump 5, and drive motor according to the feed amount of the fly ash feeder 2, so as to achieve stable wetting of fly ash.

[0033] The method for atomizing and wetting tar-containing fly ash from biomass gasification using the above-mentioned device includes the following steps: S1: Add demineralized water to the water tank. Based on the component detection results of the fly ash to be treated, use a metering pump to deliver the prepared surfactant and defoamer to the water tank in a preset ratio. Control the concentration of surfactant in the solution within the water tank to be within the range of 10-500 ppm, and the concentration of defoamer to be within the range of 5-50 ppm. Generally, when the tar content in the fly ash is high, the concentration of surfactant and defoamer in the solution within the water tank is relatively high; when the tar content in the fly ash is low, the concentration of surfactant and defoamer is relatively low. Simultaneously, a compound system of nonionic and anionic surfactants is used. When preparing the surfactant, the nonionic and anionic surfactants can be mixed in a mass ratio between 1:4 and 4:1, depending on the characteristics of the fly ash components. That is, by adjusting the ratio of nonionic to anionic surfactants, the complementarity of tar molecules with different polarities and lipophilic molecules is achieved, enhancing the penetration and dispersion ability of the compound surfactant on complex tar structures.

[0034] S2: Close the spray valve, open the circulation valve, and start the humidification pump to allow the surfactant and defoamer added to the water tank to be quickly and evenly mixed through the circulation branch.

[0035] S3: After the solution is evenly mixed, open the spray valve and close the circulation valve. The mixed solution is transported through the pipeline to the atomizing nozzle and atomized into droplets with a particle size of 30-100μm. The droplets are then sprayed out in segments along the axial direction of the humidifying and mixing mechanism. Simultaneously, the dry fly ash containing tar in the ash silo is transported to the inlet of the humidifying and mixing mechanism through the fly ash feeder. The drive motor of the screw conveyor is started, which forces the fly ash to be stirred while transporting it, ensuring that the fly ash and droplets are fully mixed. The speed of the drive motor, the flow rate and flow rate of the atomizing nozzle are all linked with the real-time feed rate of the fly ash feeder, so that the fly ash feed rate matches the amount of solution sprayed from the atomizing nozzle and there is sufficient contact and mixing time. The residence time of the fly ash in the humidifying mixer is controlled to be 10-60 seconds, and the moisture content is controlled to be 15-30% to achieve a stable wetting effect. S4: The wet ash after wetting and mixing is discharged from the outlet of the humidifying and mixing mechanism.

[0036] The above are only some embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various combinations and modifications of the aforementioned technical features. Any improvements, modifications, equivalent substitutions, or applications of the structure or method of the present invention to other fields to achieve the same effect without departing from the spirit and scope of the present invention shall fall within the protection scope of the present invention.

Claims

1. A device for atomizing and wetting tar-containing fly ash from biomass gasification, characterized in that, include: Water tanks are used for storing and mixing solutions; A pharmaceutical supply system, connected to the water tank, is used to add surfactants and defoamers to the water tank; The humidifying and stirring mechanism includes a housing, a screw conveying mechanism disposed within the housing, and a drive motor for driving the screw conveying mechanism to work. The housing is provided with an inlet and an outlet. The atomizing spraying mechanism includes a humidifying pump and multiple atomizing nozzles connected to the humidifying pump via pipelines. The inlet of the humidifying pump is connected to the water tank. The atomizing nozzles are disposed inside the housing of the humidifying and stirring mechanism and are arranged in segments along the axial direction of the spiral conveying mechanism to atomize the solution in the water tank and spray it into the housing. The fly ash feeder has its outlet connected to the inlet of the humidifying and mixing mechanism, and is used to transport the tar-containing dry fly ash in the ash silo to the inlet of the humidifying and mixing mechanism.

2. The atomizing and wetting device for biomass gasification tar-containing fly ash according to claim 1, characterized in that... The reagent supply system includes a surfactant storage tank for storing surfactants, a defoamer storage tank for storing defoamers, and a metering pump. The metering pump is used to pump the surfactants and defoamers into the water tank in a set ratio, so that the mass concentration of surfactants in the water tank solution is 10-500 ppm and the mass concentration of defoamers is 5-50 ppm.

3. The atomizing and wetting device for biomass gasification tar-containing fly ash according to claim 1, characterized in that... The surfactant is a compound of nonionic surfactant and anionic surfactant in a mass ratio of 1:4 to 4:

1.

4. The atomizing and wetting device for biomass gasification tar-containing fly ash according to claim 3, characterized in that... The nonionic surfactant is any one of alkylphenol polyoxyethylene ether or fatty alcohol polyoxyethylene ether; the anionic surfactant is any one of sodium dodecylbenzene sulfonate or sodium olefin sulfonate; and the defoamer is an organosilicon defoamer.

5. The atomizing and wetting device for biomass gasification tar-containing fly ash according to claim 1, characterized in that... A spray valve is provided on the pipeline between the atomizing nozzle and the outlet of the humidifying pump. A circulation branch is provided between the outlet of the humidifying pump and the water tank, and a circulation valve is provided on the circulation branch.

6. The atomizing and wetting device for biomass gasification tar-containing fly ash according to claim 1, characterized in that... The atomizing nozzle is a nozzle that produces droplets with a particle size of 30-100μm; the spiral conveying mechanism is any one of a single-axis spiral, a double-axis spiral, or a shaftless spiral structure.

7. The atomizing and wetting device for biomass gasification tar-containing fly ash according to claim 1, characterized in that... The outlet of the humidifying and mixing mechanism is equipped with a baffle or is designed with an inclined angle to ensure that the solution sprayed into the humidifying and mixing mechanism has sufficient contact time with the dry fly ash.

8. The atomizing and wetting device for biomass gasification tar-containing fly ash according to claim 1, characterized in that... It also includes a control unit, which is signal-connected to the fly ash feeder, the metering pump in the reagent supply system, the humidifying pump in the atomizing spraying mechanism, and the drive motor in the humidifying and stirring mechanism. The control unit is used to control the working status of the metering pump, the humidifying pump, and the drive motor in conjunction with the feed rate of the fly ash feeder to achieve stable wetting of the fly ash.

9. A method for atomizing and wetting tar-containing fly ash from biomass gasification, using the apparatus as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: Add demineralized water to the water tank. Based on the component detection results of the fly ash to be treated, use a metering pump to deliver surfactant and defoamer to the water tank in a preset ratio. Control the concentration of surfactant in the solution in the water tank to be within the range of 10-500ppm and the concentration of defoamer to be within the range of 5-50ppm. S2: Close the spray valve, open the circulation valve, and start the humidification pump to allow the surfactant and defoamer added to the water tank to be quickly and evenly mixed through the circulation branch; S3: After the solution is thoroughly mixed, open the spray valve and close the circulation valve. The mixed solution is then transported through the pipeline to the atomizing nozzle, where it is atomized into droplets with a particle size of 30-100μm and sprayed out in segments along the axial direction of the humidifying and mixing mechanism. Simultaneously, the dry fly ash containing tar in the ash silo is transported to the inlet of the humidifying and mixing mechanism via the fly ash feeder. The drive motor of the screw conveyor is started, causing the screw conveyor to forcibly stir the fly ash while transporting it, ensuring that the fly ash and droplets are fully contacted and mixed. The residence time of the fly ash in the humidifying mixer is controlled to be 10-60 seconds, and the moisture content is controlled to be 15-30%. S4: The wet ash after wetting and mixing is discharged from the outlet of the humidifying and mixing mechanism.

10. The atomization and wetting method for biomass gasification tar-containing fly ash according to claim 9, characterized in that: In step S3, the rotational speed of the drive motor of the screw conveyor and the flow rate of the atomizing nozzle are linked with the real-time feed rate of the fly ash feeder, so that the fly ash feed rate matches the solution spray rate and has sufficient contact mixing time, thereby achieving a stable wetting effect.

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