A method and system for tunnel construction air management

Abstract

The application belongs to the technical field of tunnel construction environment control, and specifically relates to a tunnel construction air treatment method and system. The problems of inefficient and collaborative removal of high-concentration hydrophobic dust and harmful gas and lack of intelligent dynamic regulation are solved, which comprises the following steps: setting an atomization unit in a tunnel pollution source area and setting an electric field purification unit downstream of the airflow; monitoring the concentration and composition of pollutants in real time through a sensor network; adding a medicament to the atomization unit according to the monitoring data, so that the medicament atomizes and acts on dust particles to change the surface charge characteristics and enhance the hydrophilicity; delivering the airflow containing pollutants to the electric field purification unit through an airflow guiding device; in the electric field purification unit, the particulate matter and gaseous pollutants are synchronously removed by using a high-voltage electric field; and based on the characteristics of the pollutant composition, the type of the medicament used is dynamically switched.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction environmental control technology, specifically a method and system for air pollution control during tunnel construction. Background Technology

[0002] During drill-and-blast tunnel construction, blasting, excavation, loading, and transportation operations generate large amounts of dust (including respirable dust PN2.5 / PM10), as well as carbon monoxide (CO) and nitrogen oxides (NOx). x Harmful gases such as dust are present. The dust concentration at the tunnel face is extremely high and the composition is complex (often containing hydrophobic substances such as silica and rock fragments). The smoke is pervasive, resulting in low visibility inside the tunnel, seriously endangering the occupational health of construction workers (such as the risk of silicosis), affecting the normal operation of machinery and equipment, and restricting the construction progress and quality.

[0003] Currently, commonly used methods for controlling air pollution in tunnels mainly include:

[0004] 1. Single-spray dust suppression: Utilizes high-pressure water mist or ordinary spray devices. Disadvantages: Low efficiency in capturing hydrophobic dust, slow dust suppression speed, and ineffective removal of gaseous pollutants (CO, NO). x This method consumes a large amount of water and may increase humidity inside the tunnel, affecting operations.

[0005] 2. Mechanical ventilation for dust removal: This method uses fans and ducts to ventilate, dilute, and exhaust pollutants. Disadvantages: It can only transfer and dilute pollutants, but cannot fundamentally and efficiently remove them, especially effective for high concentrations of dust and locally concentrated fumes; it also has high energy consumption, and its efficiency decreases significantly over long distances.

[0006] 3. Single-end purification, such as using a dust collector or simple adsorption device. Disadvantages: It usually only targets particulate matter or a single gaseous pollutant, making it difficult to treat multiple pollutants in a coordinated manner; high concentrations of dust at the front end can easily cause equipment blockage or failure; and there is a lack of linkage control with the pollution source.

[0007] The existing technical solutions generally have the following core problems: (1) They cannot efficiently and synergistically remove dust and harmful gases (CO, NOx). (2) They lack the ability to quickly and efficiently capture hydrophobic dust. (3) The treatment methods are singular, lacking an integrated and systematic solution from the source (working face) to the end. (4) They lack intelligent and dynamic control capabilities based on real-time monitoring data, resulting in unstable treatment efficiency or high operating costs.

[0008] Therefore, there is an urgent need to develop a systematic tunnel air treatment method that can quickly and efficiently reduce dust at the source, simultaneously remove multiple harmful gases, and intelligently adjust according to working conditions. Summary of the Invention

[0009] This invention addresses the shortcomings of existing air control technologies used in drill-and-blast tunnel construction, particularly their inability to efficiently and synergistically remove high concentrations of hydrophobic dust and harmful gases (CO, NO). x This paper addresses the issues of lack of intelligent dynamic control and provides a method and system for air pollution control during tunnel construction.

[0010] This invention adopts the following technical solution: a method for air pollution control during tunnel construction, comprising:

[0011] Atomizing units are installed in the pollution source area of ​​the tunnel, and electric field purification units are installed downstream of the airflow;

[0012] Real-time monitoring of pollutant concentration and composition via sensor network;

[0013] Based on monitoring data, a reagent is added to the atomization unit so that the reagent is atomized and acts on the dust particles, changing their surface charge characteristics to enhance hydrophilicity.

[0014] The airflow containing pollutants is transported to the electric field purification unit through an airflow guiding device;

[0015] In the electric field purification unit, particulate matter and gaseous pollutants are removed simultaneously using a high-voltage electric field;

[0016] Based on the characteristics of pollutant composition, the type of reagent used is dynamically switched:

[0017] When the pollutants are mainly dust, add charge-modifying agents;

[0018] When the pollutants contain nitrogen oxides, denitrification agents should be added.

[0019] In some embodiments, the charge-modifying agent is a cationic surfactant solution; the denitrification agent is a solution containing urea or hydrogen peroxide.

[0020] In some embodiments, the operating voltage of the high-voltage electric field is dynamically adjusted according to the particulate matter concentration at the inlet of the electric field purification unit:

[0021] For every 50 mg / m³ increase in particulate matter concentration, the operating voltage increases by 10 kV.

[0022] In some embodiments, the front-end parameters are adjusted based on the monitoring data feedback from the outlet of the electric field purification unit:

[0023] If the PM10 at the outlet is greater than 5 mg / m³, then increase the power of the atomizing unit or increase the dosage of the charge-modifying agent.

[0024] If export NO x If the concentration is >15 ppm, increase the dosage of denitrification agent or switch to a more effective agent.

[0025] In some embodiments, an auxiliary agent injection point is added at the inlet of the electric field purification unit. When a sudden increase in nitrogen oxide concentration exceeding 25% is detected, a high concentration of denitrification agent is directly injected into the airflow to enhance the treatment.

[0026] In some embodiments, the method further includes the following steps after all the steps:

[0027] The airflow passes through the activated carbon adsorption unit to remove residual organic matter;

[0028] Regularly remove the dust and waste collected by the electric field purification unit, and collect and treat wastewater containing chemicals.

[0029] A tunnel construction air purification system, and a method for performing the aforementioned tunnel construction air purification, comprising:

[0030] The atomizing unit is located in the pollution source area;

[0031] The electric field purification unit is located downstream of the airflow;

[0032] Sensor networks monitor pollutant composition;

[0033] The reagent dosing unit includes: a charge-modified reagent storage tank, a denitrification reagent storage tank, and a switching valve assembly;

[0034] The control unit is configured to control the switching valve group to select between the charge-modified agent storage tank and the denitrification agent storage tank based on the characteristics of the pollutant composition.

[0035] In some embodiments, the electric field purification unit integrates a voltage regulator to automatically adjust the operating voltage in response to the inlet particulate matter concentration signal.

[0036] In some embodiments, the control unit is further configured to:

[0037] Receive data from the export sensor;

[0038] When the outlet PM10 > 5 mg / m³, increase the power of the atomization unit;

[0039] When the NOx concentration at the outlet exceeds 15 ppm, increase the dosage of denitrification reagent.

[0040] In some embodiments, an auxiliary agent injector located at the inlet of the electric field purification unit is also included, which is independently controlled by the control unit and is used to directly inject concentrated denitrification agent into the airflow.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. Highly efficient and synergistic treatment: It creatively integrates the front-end "ultrasonic atomization + chemical charge modification" rapid dust reduction technology with the back-end "electrostatic capture" deep purification technology, realizing the integrated, highly efficient and synergistic removal of dust and harmful gases.

[0043] 2. Rapid dust reduction at the source: The agent changes the dust charge, which significantly improves the capture efficiency and agglomeration and settling speed of water mist for hydrophobic dust, thus greatly reducing the high concentration of dust at the working face from the source.

[0044] 3. The deep purification electrostatic precipitator has a high efficiency in removing fine particulate matter and gaseous pollutants, ensuring the cleanliness of the end exhaust.

[0045] 4. Intelligence and Adaptability: (1) Based on real-time monitoring of multiple parameters, the system can automatically sense changes in pollution status. (2) It can intelligently and dynamically adjust key operating parameters to achieve precise treatment and avoid over- or under-treatment. (3) It can automatically select the optimal agent type according to the identified pollutant components, significantly improving targeting and overall removal efficiency.

[0046] 5. Significant and stable effects:

[0047] (1) After applying the method of this invention, the concentrations of PM2.5 and PM10 in the working area inside the tunnel can be rapidly reduced to below the national standards. (2) CO and NO x The concentration removal rate can exceed 60%. (3) The visibility of the air inside the tunnel is significantly improved, reaching more than 200 meters, which meets the requirements for safe construction visibility. (4) The system has a fast response speed and can effectively cope with the sudden increase in pollutant concentration after blasting, and maintain the air quality to meet the standards continuously.

[0048] 6. Economic efficiency: Intelligent control avoids waste of reagents and energy, reducing overall operating costs. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the overall process flow of the method of the present invention.

[0050] Figure 2 This is a schematic diagram illustrating the treatment process of the present invention;

[0051] Figure 3 A schematic diagram illustrating the principle of ultrasonic atomization combined with agents to change the charge of dust.

[0052] Figure 4 This is a schematic diagram of the system structure of the present invention;

[0053] Figure 5 This is a flowchart of the control system logic.

[0054] Figure 6 Here is a chemical structural diagram of an example of the reagent used;

[0055] Figure 7 This is a schematic diagram illustrating the principle of the reaction between the reagent and the pollutant.

[0056] In the diagram, 10 is the atomization unit, 20 is the electric field purification unit, 30 is the sensor network, 40 is the reagent dosing unit, and 50 is the control unit. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] like Figure 1 As shown, a method for air pollution control during tunnel construction includes:

[0059] S1: Atomizing units are installed in the pollution source area of ​​the tunnel, and electric field purification units are installed downstream of the airflow.

[0060] The pollution source area in tunnels is generally the tunnel face. The atomization unit uses an ultrasonic atomizer: the power is adjustable from 1 to 5 kW, the atomization frequency is 1.7 to 2.4 MHz, and it produces fine water mist with a particle size of 1 to 50 μm. It is installed on the arch or sidewall near the tunnel face.

[0061] The chemical storage tanks and dosing system comprise at least two independent tanks; tank 1 stores a cationic surfactant solution (e.g., 0.1%-1.0% CTAC aqueous solution), and tank 2 stores a denitrification chemical solution (e.g., 5%-10% urea solution or 1%-5% H2O2 solution). Equipped with metering pumps, flow meters, and pressure sensors, the system precisely controls the dosage and pressure of the chemicals. The dosing point is located at the inlet of the ultrasonic atomizer or upstream of the atomization zone.

[0062] S2: Real-time monitoring of pollutant concentration and composition via sensor network.

[0063] Sensor network: Deployed 5-10 meters behind the working face, in the middle of the transport section, and at the entrance of the rear purification unit. Includes: laser scattering dust sensors for monitoring PM2.5 and PM10 concentrations; electrochemical or infrared CO sensors; and electrochemical NOx sensors.

[0064] S3: Add reagent to the atomization unit based on monitoring data, so that the reagent is atomized and acts on the dust particles to change their surface charge characteristics and enhance hydrophilicity.

[0065] Specifically, the charge-modifying agent is a cationic surfactant solution; the denitrification agent is a solution containing urea or hydrogen peroxide.

[0066] The control unit starts or increases the power of the ultrasonic atomizer based on the real-time dust concentration.

[0067] At the same time, the components of the pollutants were analyzed:

[0068] If the main pollution source is dust (PM10 significantly increased, CO / NO...) x At a low level, the control unit starts the metering pump of the reagent storage tank 1 and adds cationic surfactant solution according to the calculated amount (such as dust concentration x coefficient).

[0069] If a rapid increase in NOx concentration is detected, the control unit closes the channel of reagent storage tank 1 and opens the channel of reagent storage tank 2 to add denitrification reagent.

[0070] The drug solution is inhaled or injected into the nebulization system and ultrasonically atomized to form a drug-loaded micro-mist.

[0071] The drug-loaded micro-mist mixes thoroughly with the dust cloud, and the drug quickly acts on the surface of the dust, changing its charge and hydrophilicity. The dust particles rapidly agglomerate, increase in weight, and settle.

[0072] S4: The airflow containing pollutants is transported to the electric field purification unit through the airflow guiding device.

[0073] The airflow guiding device uses a high-pressure fan and exhaust duct: the high-pressure fan is frequency-controlled, with a power of 5.5-22 kW, an air volume of 1000-10000 m³ / h, and an air pressure of 500-3000 Pa. It is installed in a suitable location in the transportation section.

[0074] Exhaust duct: Corrosion-resistant duct that directs polluted airflow to the downstream purification unit.

[0075] The transport section guides the operation of high-pressure fans (power adjusted according to the total amount of pollutants) to remove the remaining loose dust, modified dust clumps, and CO / NO content after settling. x The airflow is drawn in through the exhaust duct and transported to the inlet of the electric field purification unit at the rear of the tunnel.

[0076] S5: In the electric field purification unit, particulate matter and gaseous pollutants are removed simultaneously using a high-voltage electric field;

[0077] Based on the characteristics of pollutant composition, the type of reagent used is dynamically switched:

[0078] When the pollutants are mainly dust, add charge-modifying agents;

[0079] When the pollutants contain nitrogen oxides, denitrification agents should be added.

[0080] Specifically, the electric field purification unit employs an electrostatic precipitator: horizontal or vertical, with an electrode spacing of 150-300 mm. The air volume is matched to the fan. Its core function is to collect charged particulate matter and promote CO / NOx removal under the assistance of a high-voltage electric field.

[0081] Activated carbon adsorption device: Located downstream of the electrostatic precipitator, it is filled with columnar or honeycomb activated carbon to further remove organic matter and odors.

[0082] The operating voltage of the high-voltage electric field is dynamically adjusted based on the particulate matter concentration at the inlet of the electric field purification unit.

[0083] For every 50 mg / m³ increase in particulate matter concentration, the operating voltage increases by 10 kV.

[0084] Specifically, an auxiliary agent injection point is added at the inlet of the electric field purification unit. When a sudden increase of more than 25% in the concentration of nitrogen oxides is detected, a high concentration of denitrification agent is directly injected into the airflow to enhance the treatment.

[0085] In a specific embodiment, the control unit sets or adjusts the electric field voltage according to the concentration of pollutants at the inlet.

[0086] Particulate matter is charged in a high-voltage electric field and captured by the dust collecting electrode. The electric field environment and any residual chemical components (such as urea and H2O2) contribute to the emission of CO and NO. x The gas undergoes oxidation, decomposition, or chemical transformation. The gas flow then passes through an activated carbon adsorption layer for further purification. The purified gas is then discharged from the tunnel or recycled. Collected dust is periodically removed by vibration or rinsing; waste liquid / residue is collected and treated.

[0087] Specifically, sensors at key locations continuously monitor the processed air quality.

[0088] All monitoring data is fed back to the control unit in real time. The control unit runs a built-in algorithm:

[0089] If the PM10 at the outlet is still >5 mg / m³, increase the front-end atomization power or the amount of reagent added, or check the electrostatic precipitator parameters.

[0090] If export NO x If the concentration is >15 ppm, the dosage of denitrification agent needs to be increased or a more effective agent needs to be switched.

[0091] If a sudden increase in the concentration of a certain pollutant is detected in a specific area, the corresponding reagent will be added and the fan power will be adjusted immediately, even if the average value does not exceed the standard.

[0092] When all parameters stabilize below the set threshold, the atomization intensity, reagent dosage, and fan power are automatically reduced to maintain the level, saving energy.

[0093] An additional reagent injection point is added at the inlet of the back-end purification unit. When the back-end sensor detects a high concentration of a specific pollutant, the control unit can directly and precisely add a targeted high-concentration reagent at that point for enhanced treatment.

[0094] All steps are followed by:

[0095] The airflow passes through the activated carbon adsorption unit to remove residual organic matter;

[0096] Regularly remove the dust and waste collected by the electric field purification unit, and collect and treat wastewater containing chemicals.

[0097] As shown in the figure, a tunnel construction air purification system, a method for completing air purification during tunnel construction, includes: an atomization unit 10, located in the pollution source area; an electric field purification unit 20, located downstream of the airflow; a sensor network 30, monitoring pollutant components; a reagent dosing unit 40, including: a charge-modified reagent storage tank, a denitrification reagent storage tank, and a switching valve group; and a control unit 50, configured to: control the switching valve group to select the reagent type based on the characteristics of pollutant components.

[0098] The electric field purification unit 20 integrates a voltage regulator 21, which automatically adjusts the operating voltage in response to the inlet particulate matter concentration signal.

[0099] The control unit 50 is further configured to: receive outlet sensor data; increase the power of the atomizing unit when outlet PM10 > 5 mg / m³; and increase the dosage of denitrification agent when outlet NOx > 15 ppm.

[0100] It also includes an auxiliary agent injector 60 located at the inlet of the electric field purification unit 20, which is independently controlled by the control unit 50 and is used to directly inject concentrated denitrification agent into the airflow.

[0101] Implementation Results Example

[0102] This system was applied in a railway tunnel drilling and blasting construction section. After one blast, the PM10 concentration at the tunnel face instantaneously reached 350 mg / m³, and NO... x Rising to 45 ppm. System triggered:

[0103] 1. The power of the ultrasonic atomizer has been increased to 4kW.

[0104] 2. NO detected x If the level exceeds the limit, the system will automatically switch to and add urea solution.

[0105] 3. The fan power was increased to 40Hz. Within 120 seconds, PM10 in the working face area decreased to 45 mg / m³, and NO... x It dropped to 32 ppm. The airflow was directed to the rear end.

[0106] 4. The electrostatic precipitator operates at 55kV.

[0107] 5. Back-end outlet monitoring shows: PM10 remains stable below 8 mg / m³, NO... xThe concentration dropped to 12 ppm, and CO was less than 10 ppm. Visibility inside the tunnel recovered to approximately 250 meters. The system then automatically reduced its operating parameters to a maintenance state.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for air pollution control during tunnel construction, characterized in that, include: Atomizing units are installed in the pollution source area of ​​the tunnel, and electric field purification units are installed downstream of the airflow; Real-time monitoring of pollutant concentration and composition via sensor network; Based on monitoring data, a reagent is added to the atomization unit so that the reagent is atomized and acts on the dust particles, changing their surface charge characteristics to enhance hydrophilicity. Adjusting front-end parameters based on feedback from monitoring data at the outlet of the electric field purification unit: If the PM10 at the outlet is greater than 5 mg / m³, then increase the power of the atomizing unit or increase the dosage of the charge-modifying agent. If export NO x If the concentration is >15ppm, increase the dosage of denitrification agent or switch to a more effective agent; An auxiliary agent injection point is added at the inlet of the electric field purification unit. When a sudden increase in nitrogen oxide concentration exceeding 25% is detected, a high concentration of denitrification agent is directly injected into the airflow to enhance the treatment. The airflow containing pollutants is transported to the electric field purification unit through an airflow guiding device; In the electric field purification unit, particulate matter and gaseous pollutants are removed simultaneously using a high-voltage electric field; Based on the characteristics of pollutant composition, the type of reagent used is dynamically switched: When the pollutants are mainly dust, add charge-modifying agents; When the pollutants contain nitrogen oxides, denitrification agents are added; The charge-modifying agent is a cationic surfactant solution; the denitrification agent is a solution containing urea or hydrogen peroxide.

2. The method for air pollution control during tunnel construction according to claim 1, characterized in that, The operating voltage of the high-voltage electric field is dynamically adjusted based on the particulate matter concentration at the inlet of the electric field purification unit. For every 50 mg / m³ increase in particulate matter concentration, the operating voltage increases by 10 kV.

3. The method for air pollution control during tunnel construction according to claim 1, characterized in that, All steps are followed by: The airflow passes through the activated carbon adsorption unit to remove residual organic matter; Regularly remove the dust and waste collected by the electric field purification unit, and collect and treat wastewater containing chemicals.

4. A tunnel construction air purification system, used to perform the tunnel construction air purification method as described in any one of claims 1-3, characterized in that, include: Atomizing unit (10) is installed in the pollution source area; The electric field purification unit (20) is located downstream of the airflow; Sensor network (30) monitors pollutant composition; The reagent dosing unit (40) includes: a charge-modified reagent storage tank, a denitrification reagent storage tank, and a switching valve group; The control unit (50) is configured to control the switching valve group to select between the charge-modified agent storage tank and the denitrification agent storage tank based on the characteristics of the pollutant composition.

5. The tunnel construction air purification system according to claim 4, characterized in that: The electric field purification unit (20) integrates a voltage regulator, which automatically adjusts the operating voltage in response to the inlet particulate matter concentration signal.

6. The tunnel construction air purification system according to claim 4, characterized in that: The control unit (50) is further configured to: Receive data from the export sensor; When the outlet PM10 > 5 mg / m³, increase the power of the atomizing unit; When NOx at the outlet exceeds 15 ppm, increase the dosage of denitrification reagent.

7. The tunnel construction air purification system according to claim 4, characterized in that: It also includes an auxiliary agent injector located at the inlet of the electric field purification unit (20), which is independently controlled by the control unit (50) and is used to directly inject concentrated denitrification agent into the airflow.

Images