Road construction dust removal equipment

Abstract

The invention discloses dust removal equipment for road construction and belongs to the technical field of dust removal equipment, the dust removal equipment comprises a cyclone section, a spraying section and an adsorption section, the cyclone section is composed of a cyclone dust collector, two-phase separation is realized by utilizing the density difference between a medium phase and a particle phase in waste gas, and after gas enters from a gas inlet, due to a special conical structure of a cyclone section separator, the gas is separated from the cyclone dust collector; linear motion of airflow is converted into high-speed rotating motion, and dust particles are thrown to the cylinder wall under the centrifugal force far larger than the gravity of the dust particles and finally settle in a dust collection box at the bottom of the cyclone dust collector; the efficient purification of the waste gas with complex components is realized through a multi-stage segmented treatment mode; the tangential speed of the rising cyclone in the center of the cyclone section separator is reduced along with the increase of the depth of the exhaust pipe, so that tiny dust particles are more difficult to be taken away from the cyclone by the rising airflow, the settled dust is prevented from being raised again, and the separation efficiency is improved. And the dust removal efficiency of road construction is improved.

Description

Technical Field

[0001] This invention belongs to the field of dust removal equipment technology, and specifically relates to a dust removal device for road construction. Background Technology

[0002] Road construction often generates large amounts of dust, which not only pollutes the construction area but can also spread with the wind to surrounding areas, adversely affecting the atmospheric environment. Long-term high concentrations of dust pollution can exacerbate air pollution, impact air quality, and pose a potential threat to the ecological environment and biodiversity.

[0003] Most dust contains various harmful substances, such as particulate matter (PM10, PM2.5), heavy metals, and organic matter, which have adverse effects on human health. Construction workers exposed to high concentrations of dust for extended periods are prone to respiratory and cardiovascular diseases. Simultaneously, nearby residents and pedestrians may also be affected by dust pollution, harming their health. Therefore, environmentally friendly dust control is an important measure to protect the health of construction workers and the public. Currently, many dust removal systems involve installing several water pipes on the side of the protective wall, with atomizing nozzles installed at intervals. The water flow, through the water pipes and atomizing nozzles, forms a water mist to remove dust from the surrounding area. However, many atomizing nozzles have a fixed spray range, which means they cannot remove dust from different distances. This makes it easy for fine dust particles at the near end to be carried up by the rising airflow, causing the settled dust to be stirred up again, which is not conducive to improving the dust removal effect. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a road construction dust removal device, comprising: a cyclone section, a spray section, and an adsorption section. The cyclone section is composed of a cyclone dust collector, which utilizes the density difference between the medium phase and the particulate phase in the exhaust gas to achieve two-phase separation. After the gas enters from the inlet, due to the special conical structure of the cyclone separator, the airflow changes from linear motion to high-speed rotational motion. Dust particles are subjected to centrifugal force much greater than their own weight and are thrown towards the cylinder wall, eventually settling in the dust collection box at the bottom of the cyclone dust collector. The multi-stage segmented treatment method achieves efficient purification of exhaust gas with complex components. Based on the established geometric model, the weak structure of the system is further optimized by evaluating the frequency, strain, and mode shape of the system structure under each mode.

[0005] Furthermore, the cyclone section is connected to the spray section through a pipeline. The exhaust gas is pre-treated in the cyclone section before entering the spray section. The spray section consists of a spray tank, spray pipes, a pump, and a demister.

[0006] Furthermore, the alkaline liquid stored in the spray tank is circulated and sprayed in the spray tank through a pump and spray pipes to absorb sulfides in the waste gas; the spray section is connected to the activated carbon adsorption section through pipes, and the activated carbon adsorption box contains honeycomb activated carbon and a centrifugal fan is installed on the top.

[0007] Furthermore, to increase the bending strength of the pipe between the cyclone separator and the spray tank, the 95mm inner diameter cylindrical pipe was replaced with a 75mm×75mm square cylindrical pipe, and the constraint between it and the spray pipe was increased. The depth of the cyclone separator exhaust pipe was changed from 380mm to 20mm, and it was connected to the spray tank with pins and connecting columns, with one pin every 340mm, for a total of 3 pins.

[0008] Furthermore, the connecting pipe between the spray section and the activated carbon adsorption section is optimized. The constraint on the pipe between the spray tank and the activated carbon adsorption box is increased. The pipe is connected to the spray tank using pins and connecting columns, with one pin installed every 377mm, for a total of 3 pins.

[0009] Furthermore, 4mm grid-shaped reinforcing ribs are added to the inner wall of the activated carbon adsorption box, and 4mm X-shaped reinforcing ribs are used in the middle area. Four 10mm×10mm columns are added around the centrifugal fan.

[0010] The beneficial effects of this invention include: This invention provides a road construction dust suppression device, comprising a cyclone section, a spray section, and an adsorption section. The cyclone section consists of a cyclone dust collector, which utilizes the density difference between the medium phase and the particulate phase in the exhaust gas to achieve two-phase separation. After the gas enters through the inlet, due to the special conical structure of the cyclone separator, the airflow changes from linear motion to high-speed rotational motion. Dust particles are subjected to centrifugal force much greater than their own weight and are thrown against the cylinder wall, eventually settling in the dust collection box at the bottom of the cyclone dust collector. This multi-stage segmented treatment achieves efficient purification of complex exhaust gases. Based on the established geometric model, by evaluating the frequency, strain, and mode shape of the system structure at various modes, the weak structural features of the system are further optimized. The tangential velocity of the rising cyclone at the center of the cyclone separator decreases with increasing exhaust pipe depth, making it more difficult for tiny dust particles to be carried away from the cyclone by the rising airflow, preventing the settled dust from being re-raised, and improving separation efficiency. This improves the efficiency of road construction dust suppression. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of a road construction dust removal device according to an embodiment of the present invention; Figure 2 This is a top view of a road construction dust removal device according to the present invention; The components are: 1. Cyclone section; 2. Spray section; 3. Activated carbon adsorption section; 4. Air inlet; 5. Exhaust outlet. Detailed Implementation

[0013] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0014] like Figure 1-2 As shown, this invention discloses a road construction dust removal device, comprising a cyclone section 1, a spray section 2, and an activated carbon adsorption section 3. It achieves efficient purification of complex-component waste gas through multi-stage segmented treatment. Based on the established geometric model, the weak structures of the system are further optimized by evaluating the frequency, strain, and mode shapes of the system structure at various modes. A flow field analysis was conducted on the cyclone section structure with dust-gas separation function, analyzing and comparing its internal flow field characteristics, turbulence intensity, tangential velocity, and velocity field vector. Based on the relevant analysis, the cyclone section design was optimized to improve the dust removal efficiency and purification effect of the dust removal system. This research has significant theoretical and engineering practical value.

[0015] The dust removal system comprises a cyclone section 1, a spray section 2, and an activated carbon adsorption section 3. The overall dimensions are 960mm × 878mm × 1180mm (length × width × height), with a vehicle-mounted space of 1300mm × 900mm × 1600mm. The cyclone section has a maximum diameter of 268mm, the spray section 2 has a diameter of 510mm and a maximum height of 1180mm, and the spray section tank has a height of 1080mm. Cyclone section 1 consists of a cyclone dust collector, utilizing the density difference between the medium phase and the particulate phase in the exhaust gas to achieve two-phase separation. After entering through inlet 4, the gas flow changes from linear motion to high-speed rotation due to the special conical structure of the cyclone separator. Dust particles are subjected to centrifugal force far exceeding their own weight and are thrown against the cylinder wall, eventually settling in the dust collection box at the bottom of the cyclone dust collector. Cyclone section 1 is connected to spray section 2 via a pipe; the exhaust gas is pre-treated in cyclone section 1 before entering spray section 2. Spray section 2 consists of a spray tank, spray pipes, a pump, and a demister. Alkaline liquid stored in the spray tank is circulated and sprayed through the pump and spray pipes to absorb sulfides in the exhaust gas. The spray section is connected to activated carbon adsorption section 3 via pipes. The activated carbon adsorption box contains honeycomb activated carbon for adsorbing potent carcinogens, and a centrifugal fan is installed at the top.

[0016] The dust removal system is installed and fixed on the asphalt hot recycling pavement maintenance vehicle. Due to the low stiffness of the entire system, it is prone to deformation under natural vibration excitation. Therefore, modal analysis is performed on the system to improve its structure.

[0017] To ensure that the element shapes generated by the finite element mesh are reasonable and to improve the accuracy and efficiency of the calculation and analysis, the geometric model is simplified as follows before establishing the finite element model: screw holes, bolts and other process holes at pipe connections are ignored; pumps and spray pipes that have little impact on the calculation structure are ignored; drawer and handle structures on the activated carbon box cabinet are ignored; and chamfers and roundings are straightened.

[0018] The entire model uses the Solid187 solid element from ANSYS, a 10-node high-order tetrahedral element that is easy to mesh, highly adaptable to the model, and capable of adaptive mesh refinement. By increasing the density of tetrahedral elements to improve computational accuracy, rather than using only hexahedral elements, this approach significantly reduces model preprocessing time. The final model consists of 357,964 elements and 712,220 nodes.

[0019] The bottom surface of the dust removal system is fixed on the asphalt hot recycling road maintenance vehicle, so the bottom surfaces of cyclone section 1, spray section 2 and activated carbon adsorption section 3 are all fixedly constrained.

[0020] Modal analysis using the finite element method yielded the first twelve natural frequencies and mode shapes of the dust removal system, revealing five relatively weak structural features. The maximum deformation in the first seven modes occurred at the connecting pipes between components, likely due to the long pipes and lack of intermediate constraints. The maximum deformation in the first and second modes occurred at the bends in the upper pipes of the cyclone separator, with a maximum deformation of 14.43 mm for the first mode. The maximum deformation in the third, sixth, and seventh modes occurred at the lower bends in the pipes connecting the spray tank and the adsorption box, with a maximum deformation of 19.464 mm for the third mode. The maximum deformation in the fourth and fifth modes occurred at the bottom of the cyclone separator exhaust pipe, with a maximum deformation of 30.373 mm for the fourth mode. The last five modes occurred at the adsorption box and the centrifugal fan at the top of the adsorption box, possibly due to the thin walls of the adsorption box. The maximum deformation in the eighth and ninth modes occurred at the centrifugal fan exhaust port 5, with a maximum deformation of 42.045 mm. The tenth, eleventh, and twelfth modes all occurred on the box walls, with a maximum deformation of 18.106 mm.

[0021] To optimize the modality, the model was improved from the following aspects: increasing the thickness of the pipes and the housing, appropriately increasing the constraints on the connecting pipes, and adding reinforcing ribs to the inner wall of the housing. Optimization of Cyclone Section 1 and Spray Section 2 involved replacing the 95mm inner diameter cylindrical pipe with a 75mm×75mm square cylindrical pipe to increase the bending strength of the pipe between the cyclone separator and the spray tank, and increasing the constraints between the pipe and the spray pipe. The depth of the cyclone separator exhaust pipe was reduced from 380mm to 20mm, and it was connected to the spray tank using pins and connecting columns, with three such connections every 340mm.

[0022] The connection pipe between spray section 2 and activated carbon adsorption section 3 is optimized by increasing the constraint on the pipe between the spray tank and the activated carbon adsorption box. Pins and connecting columns are used to connect to the spray tank, with one pin every 377mm, for a total of 3 pins.

[0023] The activated carbon adsorption box was optimized by adding 4mm grid-shaped reinforcing ribs to the inner wall of the activated carbon adsorption box, and 4mm X-shaped reinforcing ribs in the middle area. The centrifugal fan was also optimized by adding four 10mm×10mm columns around the centrifugal fan.

[0024] These improvements significantly increased the structural stiffness and improved the modal frequencies. The maximum modal deformation at the bend of the upper duct of the cyclone separator decreased to 10.181 mm, the maximum modal deformation at the bottom of the exhaust pipe decreased to 11.047 mm, and the maximum modal deformation at the lower bend of the duct connecting the spray tank and the activated carbon adsorption box decreased to 9.783 mm. The centrifugal fan exhaust port 5 is no longer a weak structure; the corresponding modal deformation has shifted to the side wall of the activated carbon adsorption box, with a maximum modal deformation of 14.451 mm. The deformation of the weak structure and the natural frequencies of the first twelve modes of the system before and after optimization are shown in Tables 1 and 2.

[0025] Cyclone section 1 is an important part for pre-treating asphalt waste gas and separating gas-solid mixtures. Due to the complex and variable fluid flow inside the cyclone separator, the effects of different structures on its separation efficiency and pressure loss are often interactive, making it difficult to analyze its internal flow field characteristics experimentally. Therefore, numerical simulation was used to analyze the impact of the "chimney effect" on dust removal efficiency when the exhaust pipe depth of the cyclone separator is different, so as to improve the structure.

[0026] Table 1 Deformation of weak structures before and after optimization Table 2 Natural frequencies of the structure before and after optimization

[0027] The main structural features of the cyclone separator include inlet height a, inlet width b, and cylinder height. Total height Exhaust pipe depth Exhaust pipe diameter cylinder diameter and dust collection port diameter The annular space is the cylindrical space of the cyclone separator, and the height of the annular space is [missing information]. The separation space is the cone-shaped space of the cyclone separator, and the height of the separation space is... .

[0028] The flow field inside the cyclone separator is an extremely complex three-dimensional, gas-solid two-phase rotating turbulent flow with significant anisotropy. Therefore, the Reynolds stress turbulence model (RSM) was chosen for analysis. The RSM model rigorously considers the effects of streamline bending and vortexes, providing higher accuracy for simulating complex turbulence.

[0029] The fundamental governing equations for RSM turbulence consist of the continuity equation, the Navier-Stokes equation, the Reynolds stress equation, the turbulent kinetic energy equation, and the dissipation rate equation. Assuming the fluid in the cyclone separator is incompressible and isothermal, the corresponding governing equations are as follows: Continuity equation:

[0030] Navier-Stokes equations:

[0031] in, j It is a constant; The viscosity coefficient of the gas; The density of the gas; This is the Reynolds stress term.

[0032] Reynolds stress transport equation:

[0033] in, For diffusion transport items; For stress production items; This is a pressure-stress correlation term; This is a dissipation term.

[0034] Turbulent kinetic energy equation:

[0035] Dissipation rate equation:

[0036] in, =1.44, =1.92.

[0037] The computationally efficient DPM model was chosen for simulating dust particles, rather than treating each particle as a separate phase (VOF multiphase flow model). Since the cyclone separator has a separation efficiency of 99% for particles with a diameter of 10 μm or larger, the dust particles simulated in this paper have a diameter of 1-10 μm, and a total of 1200 particles were tracked.

[0038] The pressure-velocity coupling equations are solved using the SIMPLE algorithm, and the discretization is controlled using the QUICK difference scheme with second-order accuracy.

[0039] The separation efficiency of the cyclone separator is calculated using the following formula:

[0040] Analysis shows that the static pressure in the central negative pressure zone of the cyclone separator increases with the depth of the exhaust pipe, and remains constant at the lower inlet of the exhaust pipe. This is because the exhaust pipe has a certain depth, creating a chimney effect within the cyclone separator. The high temperature of the exhaust gas inside the pipe, combined with atmospheric buoyancy, results in a certain geometric head, forming a negative pressure at the bottom of the exhaust pipe. This negative pressure generates suction, transforming the downward swirling flow in the cyclone separator into an upward swirling flow. The airflow enters from the inlet and begins to rotate. The positive pressure on both sides of the cyclone separator also increases with the depth of the exhaust pipe, thus increasing the total pressure drop.

[0041] The closer to the central core, the lower the static pressure. As the exhaust pipe depth increases, the static pressure distribution within the core becomes more uniform and symmetrical. Increased exhaust pipe depth increases the stability of the tangential velocity of the core, reduces the velocity fluctuation range, slows the rising vortex velocity, and makes it more difficult for tiny particles to be carried away from the cyclone separator by the rising airflow. This increases the separation efficiency of the cyclone separator for dust and gas, but this effect weakens when the exhaust pipe depth exceeds the annular space of the cyclone separator. Increased exhaust pipe depth also increases pressure drop, turbulence intensity, and energy dissipation, and also increases the deflection of the exhaust pipe.

[0042] The design of the cyclone section, spray section 2, and adsorption section was completed using a multi-stage combined treatment approach. The finite element method was used to perform structural modal analysis of the dust removal system, identifying five weak structural elements. The structure was optimized by increasing the thickness of the pipes and housing, appropriately increasing constraints, and adding reinforcing ribs, thereby improving the natural frequencies and strains in each mode.

[0043] The structure of the cyclone section of the dust removal system was analyzed using CFD numerical simulation. The static pressure and tangential velocity inside the cyclone section separator are basically symmetrically distributed. As the depth of the exhaust pipe of the cyclone section separator increases, the static pressure distribution and tangential velocity of the central cyclone become more symmetrical and stable. At the same time, the turbulence intensity at the bottom of the exhaust pipe increases, which increases turbulence dissipation and leads to a slight increase in pressure loss.

[0044] The tangential velocity of the rising cyclone at the center of the cyclone separator decreases with increasing exhaust pipe depth. This makes it more difficult for fine dust particles to be carried away from the cyclone by the rising airflow, preventing settled dust from being re-raised and improving separation efficiency. This effect is somewhat reduced when the exhaust pipe depth exceeds the height of the cylinder, i.e., the height of the annular space. To maximize dust removal efficiency while ensuring that the pressure loss is not too large, the exhaust pipe depth is designed to be equal to the cylinder height of 225 mm. Simulation results show that the cyclone separator achieves a separation efficiency of 94.3% for dust particles with a diameter of 1-10 μm, with a pressure loss of 429.85 Pa.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A road construction dust suppression device, characterized in that, include: Cyclone section (1), spray section (2) and activated carbon adsorption section (3). Cyclone section (1) is composed of a cyclone dust collector. It uses the density difference between the medium phase and the particulate phase in the exhaust gas to achieve two-phase separation. After the gas enters from the inlet, due to the special conical structure of the cyclone separator, the airflow changes from linear motion to high-speed rotational motion. The dust particles are subjected to centrifugal force much greater than their own weight and are thrown towards the cylinder wall, and finally settle in the dust collection box at the bottom of the cyclone dust collector. The multi-stage segmented treatment method achieves efficient purification of exhaust gas with complex components. Based on the established geometric model, the weak structure of the system is further optimized by evaluating the frequency, strain and mode shape of the system structure under each mode.

2. The road construction dust removal equipment as described in claim 1, characterized in that, The cyclone section (1) is connected to the spray section (2) through a pipeline. The exhaust gas is pretreated in the cyclone section (1) and then enters the spray section (2). The spray section (2) consists of a spray tank, a spray pipeline, a pump and a demister.

3. A road construction dust suppression device as described in claim 2, characterized in that, The alkaline liquid stored in the spray tank is circulated and sprayed in the spray tank through the pump and spray pipe to absorb the sulfides in the waste gas; the spray section (2) is connected to the activated carbon adsorption section (3) through the pipe. The activated carbon adsorption box contains honeycomb activated carbon and a centrifugal fan is installed on the top.

4. The road construction dust removal equipment as described in claim 2, characterized in that, To increase the bending strength of the pipe between the cyclone separator and the spray tank, the 95mm inner diameter cylindrical pipe was replaced with a 75mm×75mm square pipe, and the constraint between it and the spray pipe was increased. The depth of the cyclone separator exhaust pipe was changed from 380mm to 20mm, and it was connected to the spray tank with pins and connecting columns, with one pin every 340mm, for a total of 3 pins.

5. A road construction dust suppression device as described in claim 2, characterized in that, The connection pipe between the spray section (2) and the activated carbon adsorption section (3) is optimized to increase the constraint of the pipe between the spray tank and the activated carbon adsorption box. Pins and connecting columns are used to connect to the spray tank, with one pin every 377mm, for a total of 3 pins.

6. A road construction dust suppression device as described in claim 2, characterized in that, Add 4mm grid-shaped reinforcing ribs to the inner wall of the activated carbon adsorption box, and use 4mm X-shaped reinforcing ribs in the middle area. Add 4 10mm×10mm columns around the centrifugal fan.

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