A method and device for electrically dehydrating a large-scale soil body

Abstract

The application relates to the technical field of soil electro-osmotic dewatering, and particularly discloses a power-on method and a power-on device for large-scale soil electro-osmotic dewatering, the device comprising a power supply, a plurality of current distributors and a plurality of electrode groups, and the method comprising the following steps: device preparation; single-round power-on: starting voltage is applied to each electrode group through the current distributor, and the current of each group is detected; according to the size of the detected current of each group, the current of the group is controlled to be turned on or turned off or the size of the voltage of the group is adjusted through the current distributor; step-by-step voltage increase and multi-round power-on. According to the application, the on-off of the current and the voltage adjustment are controlled according to the change of the current with time in the electro-osmosis process, the electro-osmosis is kept to be carried out under suitable voltage conditions, the electro-osmosis efficiency is improved, the waste of electric energy is reduced, the energy consumption is lowered, the to-be-processed site is divided into a plurality of regions for separate control, the regional difference caused by the non-uniformity of the soil body is overcome, and the electro-osmosis of each region can be carried out under suitable voltage conditions.

Description

Technical Field

[0001] This application relates to the field of soil electro-osmotic dewatering technology, and in particular to an energizing method and energizing device for large-scale soil electro-osmotic dewatering. Background Technology

[0002] Five main electrical phenomena exist in soil: flow potential, migration potential, electroosmosis, ion electromigration, and electrophoresis. Soil electrokinetic technology, developed by utilizing these electrical phenomena, is a platform-based technology. It achieves water migration, ion migration, and electrochemical reactions within the soil by applying direct current. This technology can be applied in many fields, such as sludge dewatering, soft soil foundation treatment, contaminated soil remediation, sludge-water co-treatment, saline-alkali land management, and green rare earth mining.

[0003] For special soil types such as mudflats, tidal flats, and river channels, where soil particles are small and permeability coefficients are low, pore water cannot seep out naturally. Electroosmosis is an effective dewatering method. Electroosmosis dewatering technology involves placing the water-containing soil under an electric field. In a system where solid movement is restricted, counterions in the diffusion layer move along the slip interface towards the electrode, simultaneously driving water molecules towards the negative electrode. Water is then discharged from the negative electrode through suction or gravity drainage, thus reducing soil moisture.

[0004] In the initial stage of energization, the soil has a high water content and low resistance, resulting in a large current. As energization progresses, the soil water content decreases, the ion content in the pore water decreases, and the soil near the electrode becomes polarized, which increases the current. Most current soil electro-osmotic dehydration technologies use ordinary transformer and rectifier power supplies. The main problems are: (1) Due to the uneven properties of the soil on site, the current changes differently over time. If the same energization method is used for each area, it is difficult to produce the expected effect when energizing ineffective areas with inappropriate current and voltage, and energy is wasted; (2) When applied on a large scale, the power and energy consumption are too high, which restricts the large-scale application of soil electro-osmotic dehydration technology. Summary of the Invention

[0005] In order to improve electroosmosis efficiency and reduce power consumption, this application provides an energizing method and energizing device for large-scale soil electroosmosis dewatering.

[0006] The electro-osmotic dewatering method for large-scale soil water in this application adopts the following technical solution:

[0007] An electro-osmotic dewatering method for large-scale soil includes the following steps:

[0008] Equipment preparation: Divide the site to be treated into several areas, and bury an electrode group in the soil of each area. Each electrode group includes several positive electrode columns and several negative electrode columns. Set up a current distributor in each area, and connect the positive electrode columns and negative electrode columns in each electrode group to the positive and negative terminals of the current distributor in this area, respectively. Connect the current distributor to the power supply.

[0009] Single-wheel energization: The current distributor applies an initial voltage to each electrode group and detects the current of each group. Based on the magnitude of the detected current of each group, the current distributor controls the current on / off of that group or adjusts the voltage of that group.

[0010] Staged voltage boosting and multi-round energization: During a single-round energization process, data fitting is performed on the current change over time in each group to obtain the fitted curve I=Ae. -at +B, where I is the current, t is the energizing time, A is the coefficient, a is the time exponent, B is the current margin constant, and e is the natural constant; when the current detection value approaches B, the energizing of this group ends, and then the next energizing begins; the starting voltage of the next energizing is higher than the starting voltage of the previous energizing.

[0011] Furthermore, the single-wheel energization steps include:

[0012] If the detected current exceeds the set upper limit of the single group current, then the power supply to that group will be stopped.

[0013] If the detected current is not greater than the set upper limit of the single group current, then determine whether the detected current is less than the set lower limit of the single group current, and then adjust the voltage of that group.

[0014] Furthermore, the single-wheel energization step also includes:

[0015] If the detected current is less than the set lower limit of the single group current, the voltage of the group is gradually increased until the current reaches the set lower limit of the single group current, and the current voltage is maintained to continue to power on.

[0016] If the detected current is not less than the set lower limit of the single group current, then determine whether the voltage is trending upward, and further adjust the voltage of that group.

[0017] Furthermore, the single-wheel energization step also includes:

[0018] If the detected current is not less than the set lower limit of the single group current and the voltage shows an upward trend, then reduce the voltage of that group and continue to power on.

[0019] If the detected current is not less than the set lower limit of the single current and the voltage does not show an upward trend, maintain the current voltage and continue to supply power.

[0020] Furthermore, the single-round power-on step also includes: applying an initial voltage to the unconnected group and detecting the current at regular intervals, and controlling the group to connect or keep the group unconnected based on the magnitude of the detected current through a current distributor.

[0021] Furthermore, when the sum of the currents of all groups is less than the set upper limit of the total current, an initial voltage is applied to the unconnected group and the current is detected. Based on the magnitude of the detected current, the current distributor controls whether the group is connected or kept unconnected.

[0022] Furthermore, after each round of energization, the positive and negative terminals of the current distributor are short-circuited to release the charge; while one or more groups are releasing charge, the other groups remain energized.

[0023] Furthermore, after each short circuit ends, the polarity of the electrodes is reversed before the next round of energization is performed.

[0024] This application also provides an energizing device for large-scale soil electro-osmotic dewatering, used to implement an energizing method for large-scale soil electro-osmotic dewatering, the device comprising:

[0025] power supply;

[0026] Multiple electrode groups are buried in the soil in different areas of the site to be treated. Each electrode group includes several positive electrode columns and several negative electrode columns. The positive electrode columns include several positive electrode rods arranged in rows, and the negative electrode columns include several negative electrode rods arranged in rows. The positive electrode columns and negative electrode columns in each electrode group are arranged alternately.

[0027] Multiple current distributors correspond one-to-one with multiple electrode groups. In each electrode group, the positive electrode column and the negative electrode column are connected to the positive and negative terminals of the current distributor, respectively. The current distributor is connected to a power supply and is used to adjust the voltage applied to the corresponding electrode group. The current distributor also has a power-on parameter readback function, a polarity reversal function, a short-circuit function, and a disconnect function.

[0028] Furthermore, the device also includes a controller for controlling the on / off state and voltage regulation of the corresponding current distributors based on the current conditions of each area.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] 1. This application controls the on / off state of the current and regulates the voltage based on the change of current over time during the electroosmosis process, so as to keep the electroosmosis under appropriate voltage conditions, improve the efficiency of electroosmosis, reduce energy waste, and help reduce energy consumption;

[0031] 2. This application divides the site to be treated into several areas for separate control, which helps to overcome the regional differences caused by the unevenness of soil properties, and ensures that electroosmosis can be carried out in each area under appropriate voltage conditions, thereby improving the efficiency of electroosmosis and reducing energy waste;

[0032] 3. By eliminating electrode polarization in the soil through the short-circuit discharge process, the electroosmosis effect is enhanced and energy consumption is reduced; at the same time, the short-circuit discharge time is fully utilized to energize other areas, thereby reducing the demand for power supply. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of an energized device for large-scale soil electro-osmosis dewatering according to an embodiment of this application;

[0034] Figure 2 This is a flowchart of a single-cycle energization process in an embodiment of this application for a large-scale soil electro-osmotic dewatering method;

[0035] Figure 3 This is one of the flowcharts for connecting unconnected groups during a single-round energization process in an energization method for large-scale soil electro-osmotic dewatering according to an embodiment of this application;

[0036] Figure 4 This is the second flowchart of the process of connecting unconnected groups during a single-round energization in an energizing method for large-scale soil electro-osmotic dewatering according to an embodiment of this application.

[0037] Reference numerals: 1. Power supply; 2. Current distributor; 3. Electrode group; 3-1. Positive electrode array; 3-2. Negative electrode array. Detailed Implementation

[0038] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0039] This application discloses an electrified device for large-scale soil electro-osmosis dewatering. (Refer to...) Figure 1 The power supply device for large-scale soil electro-osmotic dewatering includes a power source 1, multiple electrode groups 3, and multiple current distributors 2 corresponding to the multiple electrode groups 3.

[0040] Reference Figure 1The site to be treated is divided into three areas, and three electrode groups 3 are buried in the three areas respectively. Each electrode group 3 includes several positive electrode rows 3-1 and several negative electrode rows 3-2. Each positive electrode row 3-1 is composed of multiple positive electrode rods arranged at intervals and connected by wires, with a spacing of 1m between adjacent positive electrode rods; each negative electrode row 3-2 is composed of multiple negative electrode rods arranged at intervals and connected by wires, with a spacing of 1m between adjacent negative electrode rods. The positive electrode rows 3-1 and negative electrode rows 3-2 in each electrode group 3 are arranged alternately at intervals of 1m.

[0041] Reference Figure 1 In each electrode group 3, the positive electrode column 3-1 and the negative electrode column 3-2 are connected to the positive and negative terminals of the current distributor 2 respectively via connectors; the current distributor 2 is connected to the power supply 1 and is used to adjust the voltage applied to the corresponding electrode group 3. The current distributor 2 also has functions for reading back energized parameters (current, voltage, etc.), polarity reversal, short-circuiting, and disconnection.

[0042] The device also includes a controller for controlling the on / off state and voltage regulation of the corresponding current distributor 2 according to the current conditions of each area.

[0043] A method for large-scale soil electro-osmotic dewatering using an electrified device includes the following steps:

[0044] Step 1, Equipment Preparation:

[0045] The site to be treated is divided into three areas. An electrode group 3 is buried in the soil of each area. Each electrode group 3 includes several positive electrode columns 3-1 and several negative electrode columns 3-2. A current distributor 2 is set in each area. The positive electrode columns 3-1 and negative electrode columns 3-2 in each electrode group 3 are connected to the positive and negative terminals of the current distributor 2 in this area, respectively. The current distributor 2 is connected to the power supply 1.

[0046] Step 2, Powering on a single wheel:

[0047] A starting voltage (e.g., 2V) is applied to each electrode group 3 via current distributor 2, and the current in each group is detected. Based on the magnitude of the detected current in each group, current distributor 2 controls the current flow of that group or adjusts the voltage of that group. Figure 2 Specifically, it includes the following steps:

[0048] Step 2.1: After applying the starting voltage, if the detected current is greater than the set upper limit of the single group current (e.g., 60A), then stop energizing that group.

[0049] Step 2.2: After applying the initial voltage, if the detected current is not greater than the set upper limit of the single-group current (60A), then determine whether the detected current is less than the set lower limit of the single-group current (e.g., 50A), and then adjust the group voltage accordingly. This includes the following steps:

[0050] Step 2.2.1: If the detected current is less than the set lower limit of the single group current (50A), then the voltage of the group is increased in a gradient (e.g., in 2V increments) until the current reaches the set lower limit of the single group current (50A), and then the current voltage is maintained and the power is continued.

[0051] Step 2.2.2: If the detected current is not less than the set lower limit of the single group current (50A), determine whether the voltage is trending upward, and then further adjust the group voltage, specifically including the following steps:

[0052] Step 2.2.2.1: If the detected current is not less than the set lower limit of the single group current (50A) and the voltage is rising, then reduce the voltage of that group and continue to power on.

[0053] Step 2.2.2.2: If the detected current is not less than the set single-group current lower limit (50A) and the voltage does not show an upward trend, then maintain the current voltage and continue to power on.

[0054] Step 2.3: Refer to Figure 3 At regular intervals (e.g., every hour), an initial voltage is applied to the unconnected packets and the current is detected. Based on the magnitude of the detected current, the current distributor 2 controls whether the packet is connected or kept unconnected. Specifically, the following steps are included:

[0055] Step 2.3.1: If the current of the unconnected group is less than the set lower limit of the single group current (50A), then determine whether the sum of the currents of all groups is less than the set upper limit of the total current (e.g., 400A). If yes, then connect the group; otherwise, keep the group unconnected.

[0056] Step 2.3.2: If the current of the unconnected group is not less than the set single group current lower limit (50A), then keep the group unconnected.

[0057] Step 2.4: Refer to Figure 4 The system reads the total current of all groups in real time. When the total current of all groups is less than the set upper limit of the total current (400A), an initial voltage is applied to the unconnected group and the current is detected. Based on the magnitude of the detected current, the current distributor controls whether the group is connected or kept unconnected. The specific steps include:

[0058] Step 2.4.1: If the current of the unconnected group is less than the set lower limit of the single group current (50A), then determine whether the sum of the currents of all groups is less than the set upper limit of the total current (400A). If yes, then connect the group; otherwise, keep the group unconnected.

[0059] Step 2.4.2: If the current of the unconnected group is not less than the set single group current lower limit (50A), then keep the group unconnected.

[0060] Step 3: Staged voltage boosting and multiple rounds of power application:

[0061] During a single-cycle energization process, the data on the change of current over time in each group is fitted to obtain the fitted curve I=Ae. -at +B, where I is the current, t is the energizing time, A is the coefficient, a is the time exponent, B is the current margin constant, and e is the natural constant.

[0062] When the current detection value approaches B, the energization of that region ends, and the positive and negative terminals of current distributor 2 are short-circuited to release the charge. During the discharge of charge by one or more groups, other groups remain energized, thereby distributing the power available from the discharged groups to other regions to maximize the utilization of power supply.

[0063] When the current generated by the released charge approaches zero, the polarity of the current distributor 2 is switched, converting the original positive electrode column 3-1 to the negative electrode column 3-2, and vice versa. The purpose of this polarity switch is that as electroosmosis proceeds, the positive electrode area becomes drier, while the negative electrode area becomes wetter. Switching the electrode polarity makes the previously dry areas wetter, thereby reducing resistance, increasing the effective electric field strength of the soil, and improving electroosmosis efficiency.

[0064] After the polarity reversal is complete, the area is energized for the next round. The starting voltage of each subsequent round of energization is higher than that of the previous round, and the starting voltages for multiple rounds of energization are set sequentially to 2V, 10V, 20V, 40V, 60V, and 80V. The method for each round of energization is the same as step 2.

[0065] This embodiment divides the site to be treated into several areas for separate control, which helps overcome regional differences caused by the heterogeneity of soil properties and ensures that electroosmosis can be carried out in each area under suitable voltage conditions. Specifically, the on / off state of the current and the voltage are controlled according to the change of current over time during the electroosmosis process, keeping the electroosmosis under suitable voltage conditions at all times, improving electroosmosis efficiency, reducing energy waste, and thus reducing energy consumption. Using the energizing method provided in this application, the energy consumption per unit volume is approximately 0.5 kWh / m². 3In contrast, the traditional method of powering a unit volume using ordinary transformers and rectifiers consumes approximately 10 kWh / m² of electrical energy. 3 , or even higher.

[0066] It should be noted that the energizing method and energizing device provided in this application can be applied not only to soil electro-osmotic dehydration, but also to other soil electro-energizing technologies, such as saline-alkali land treatment, contaminated soil remediation, and rare earth electro-energizing mining, in order to achieve the effect of reducing energy consumption.

[0067] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method of applying an electric current to large-scale soil mass electroosmotic dewatering, characterized by: The method comprises the following steps: Device preparation: divide the site to be treated into several areas, and bury an electrode group in the soil of each area, each electrode group comprising several positive electrode columns and several negative electrode columns; set a current distributor in each area, and connect the positive electrode columns and the negative electrode columns in each electrode group to the positive electrode and the negative electrode of the current distributor in the area respectively; and connect the current distributors to the power supply; Single-cycle power-on: apply a starting voltage to each electrode group through the current distributor and detect the current of each group, and control the on-off of the current of the group or adjust the voltage of the group through the current distributor according to the size of the detected current of each group; Stepwise voltage boosting and multi-round current distribution: in a single round of current distribution, the current-time curve of each group is fitted to obtain a fitting curve I=Ae -at +B, where I is the current, t is the current time, A is the coefficient, a is the time index, B is the current residual constant, and e is the natural constant; when the current detection value approaches B, the current distribution of this group is ended, and then the positive and negative electrodes of the current distributor are short-circuited to release the charge; during the discharge of one or more groups, the other groups are kept on to allocate the power left by the discharged groups to other areas to maximize the use of power as much as possible; when the current generated by the discharge approaches zero, the polarity of the current distributor is converted, and the next round of current distribution is started; the starting voltage of the next round of current distribution is higher than that of the previous round of current distribution.

2. The method of claim 1, wherein the method is characterized by: The single-cycle power-on step comprises: If the detected current is greater than the set upper limit of the current of a single group, stop the power-on of the group; If the detected current is not greater than the set upper limit of the current of a single group, determine whether the detected current is less than the set lower limit of the current of a single group, and then adjust the voltage of the group.

3. The method of claim 2, wherein the method is characterized by: The single-cycle power-on step further comprises: If the detected current is less than the set lower limit of the current of a single group, perform gradient voltage rise on the group until the current reaches the set lower limit of the current of a single group, and maintain the current power-on at the current voltage; If the detected current is not less than the set lower limit of the current of a single group, determine whether the voltage is in an upward trend, and further adjust the voltage of the group.

4. The method of claim 3, wherein the method is characterized by: The single-cycle power-on step further comprises: If the detected current is not less than the set lower limit of the current of a single group, and the voltage is in an upward trend, reduce the voltage of the group and continue the power-on; If the detected current is not less than the set lower limit of the current of a single group, and the voltage is not in an upward trend, maintain the current voltage and continue the power-on.

5. The method of claim 2, wherein the method is characterized by: The single-cycle power-on step further comprises: at intervals, apply a starting voltage to a group not connected and detect the current, and control the connection or non-connection of the group through the current distributor according to the size of the detected current.

6. The method of claim 2, wherein the method is characterized by: The single-cycle power-on step further comprises: when the total current of all groups is less than the set upper limit of the total current, apply a starting voltage to a group not connected and detect the current, and control the connection or non-connection of the group through the current distributor according to the size of the detected current.

7. The method of claim 6, wherein the method is characterized by: After each shorting is completed, the polarity of the electrodes is converted, and the next cycle of power-on is performed.

8. A power supply device for large-scale electro-osmotic dewatering of soil mass, characterized by: A device for implementing the power-on method of large-scale soil electro-osmotic dewatering according to any one of claims 1-7, the device comprising: a power supply; a plurality of electrode groups, each electrode group being buried in the soil of a different area of the site to be treated, each electrode group comprising a plurality of positive electrode columns and a plurality of negative electrode columns, each positive electrode column comprising a plurality of positive electrode rods arranged in a column, each negative electrode column comprising a plurality of negative electrode rods arranged in a column, and the positive electrode columns and the negative electrode columns in each electrode group being arranged alternately and spaced apart; a plurality of current distributors, each corresponding to one of the plurality of electrode groups, in each electrode group, the positive electrode columns and the negative electrode columns being connected to the positive electrode and the negative electrode of the current distributor respectively; the current distributors being connected to the power supply and being used to adjust the voltage applied to the corresponding electrode group; the current distributors further having a power-on parameter reading function, a polarity conversion function, a shorting function, and a disconnecting function; a controller for controlling the on-off and voltage adjustment of the corresponding current distributors according to the current conditions of the areas.

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