Carbon dioxide horizontal stratum freezing pipe liquid preparation system and method

Abstract

The invention discloses a carbon dioxide horizontal stratum freezing pipe liquid preparation system and method.Each freezing pipe branch is internally provided with a multi-sensor data fusion module and a control valve, and the multi-sensor data fusion module detects the liquid separation state variable of the corresponding freezing pipe branch in real time; the liquid separation state variables comprise the liquid carbon dioxide temperature, the pipeline pressure, the liquid carbon dioxide flow and the stratum heat conductivity coefficient, and the liquid separation control calculation module calculates the final valve opening adjustment amount corresponding to each freezing pipe branch according to the target flow value and the liquid separation state variable of each freezing pipe branch through a fuzzy-PID algorithm. And the central control module correspondingly adjusts a control valve in each freezing pipe branch according to the final valve opening adjustment amount, so that fuzzy logic and PID control are fused, and the accurate valve opening adjustment amount is obtained through coordinated regulation and control according to various variable parameters, so that the liquid separation precision and uniformity are improved, the freezing curtain continuity is enhanced, and the freezing effect is improved.

Description

Technical Field

[0001] The present invention relates to the field of underground engineering technology, in particular to a horizontal stratum freezing technology. Background Art

[0002] Ground freezing technology is a key method used in underground engineering to reinforce weak strata or block groundwater flow. It is commonly used in tunnel construction, mine support, and other fields. Carbon dioxide is widely used as a refrigerant due to its high latent heat of phase change and environmental friendliness. Existing CO2 ground freezing systems rely on manual adjustment or simple timed valve control for liquid distribution. Liquid CO2 is uniformly injected into the formation through fixed pipelines, where it absorbs heat and vaporizes to form a frozen curtain.

[0003] In the prior art, the main solutions for carbon dioxide liquid distribution systems include:

[0004] 1. Manual valve adjustment: The operator adjusts the opening of each branch valve based on experience to achieve balanced liquid distribution;

[0005] 2. Timing control method: switch the valve state through the preset time period to control the carbon dioxide flow of each branch;

[0006] 3. Pressure feedback control: fine-tune the valve opening according to the changes in pipeline pressure to maintain stable system pressure.

[0007] However, the above-mentioned liquid distribution system has low operating efficiency under complex formation conditions (such as non-uniform soil, groundwater flow, etc.), and is unable to dynamically adjust the liquid distribution plan according to the temperature and flow fluctuations of the complex formation. It is difficult to achieve precise liquid distribution, which can easily lead to problems such as uneven freezing effect, excessive energy consumption or discontinuous freezing curtain.

[0008] Therefore, how to effectively improve the liquid separation accuracy of the carbon dioxide liquid distribution system, ensure the continuity and stability of the freezing curtain, and improve the freezing effect has become an urgent problem to be solved in this field. Summary of the Invention

[0009] In view of the defects of the prior art, the purpose of the present invention is to provide a carbon dioxide horizontal stratum freezing pipe liquid distribution system and method with precise liquid separation and good freezing effect.

[0010] In order to achieve the above-mentioned purpose, the present invention provides a carbon dioxide horizontal stratum freezing pipe liquid distribution system, which includes a carbon dioxide delivery module, which is respectively connected to a plurality of freezing pipe branches, and also includes a multi-sensor data fusion module, a control valve, a liquid separation control calculation module and a central control module.

[0011] Each freezing pipe branch is provided with a multi-sensor data fusion module and a control valve. The multi-sensor data fusion module is configured to detect the liquid separation state variables of the corresponding freezing pipe branch in real time. The liquid separation state variables include liquid carbon dioxide temperature, pipeline pressure, liquid carbon dioxide flow rate and formation thermal conductivity.

[0012] The liquid separation control calculation module is configured to use a fuzzy-PID algorithm to calculate the final valve opening adjustment corresponding to each freezing pipe branch according to the target flow value of each freezing pipe branch and the liquid separation state variable.

[0013] The central control module is configured to transmit data with the multi-sensor data fusion module, the liquid separation control calculation module and the control valve, and adjust the control valve in each freezing pipe branch according to the final valve opening adjustment amount.

[0014] Furthermore, the multi-sensor data fusion module includes a temperature sensor, a pressure sensor and a flow meter.

[0015] Furthermore, the liquid separation control calculation module includes a data acquisition and input unit, a fuzzy logic reasoning unit and a PID correction unit. The data acquisition and input unit is configured to transmit the target flow value of each freezing pipe branch and the real-time collected liquid separation state variables to the fuzzy logic reasoning unit and the PID correction unit. The fuzzy logic reasoning unit is configured to process the liquid separation state variables according to a preset fuzzy rule base to generate a preliminary valve opening adjustment amount. The PID correction unit is configured to perform a fusion operation on the preliminary valve opening adjustment amount based on the target flow value and the liquid separation state variables to output the final valve opening adjustment amount.

[0016] Furthermore, the fuzzy logic reasoning unit performs fuzzification processing on the liquid separation state variables to convert them into fuzzy variables, and generates temperature deviation fuzzy sets, pressure deviation fuzzy sets and flow deviation fuzzy sets respectively. The membership function adopts triangular or Gaussian distribution, and then establishes a fuzzy rule base based on the fuzzy variables to generate a fuzzy output collection of valve opening adjustment amount. Finally, the center of gravity method is used to convert the fuzzy output into a preliminary valve opening adjustment amount.

[0017] Furthermore, the PID correction unit includes a PID control subunit, which calculates the liquid separation deviation based on the target flow value and the liquid carbon dioxide flow in the liquid separation state variable, and performs proportional, integral and differential operations based on the liquid separation deviation to output the PID valve opening adjustment amount.

[0018] Furthermore, the PID correction unit also includes a fuzzy-PID composite control subunit, which performs weighted fusion on the preliminary valve opening adjustment amount and the PID valve opening adjustment amount, and takes minimizing the liquid separation deviation and system energy consumption as the objective function to obtain the final valve opening adjustment amount and transmit it to the central control module.

[0019] Furthermore, the central control module controls the liquid separation control calculation module to calculate the final valve opening adjustment amount every 0.5 seconds.

[0020] Furthermore, the central control module includes a redundant unit, which can use the historical liquid separation state variable interpolation corresponding to the i-th freezing pipe branch or the average of the liquid separation state variables of the remaining freezing pipe branches as the liquid separation state variable compensation value of the i-th freezing pipe branch when the multi-sensor data fusion module of the i-th freezing pipe branch is abnormal.

[0021] In order to achieve the above-mentioned object, the present invention provides a method for dispensing liquid in a horizontal carbon dioxide freezing pipe, based on the aforementioned system for dispensing liquid in a horizontal carbon dioxide freezing pipe, and the method comprises:

[0022] A multi-sensor data fusion module and a control valve are installed in each freezing pipe branch. The multi-sensor data fusion module detects the liquid separation state variables of the corresponding freezing pipe branch in real time. The liquid separation state variables include liquid carbon dioxide temperature, pipeline pressure, liquid carbon dioxide flow rate and formation thermal conductivity.

[0023] The liquid separation control calculation module collects the liquid separation state variables and uses the fuzzy-PID algorithm to calculate the final valve opening adjustment corresponding to each freezing pipe branch according to the target flow value of each freezing pipe branch and the liquid separation state variables.

[0024] The central control module adjusts the control valve in each freezing pipe branch according to the final valve opening adjustment amount, and the multi-sensor data fusion module updates the liquid separation state variable in real time and feeds it back to the liquid separation control calculation module.

[0025] The carbon dioxide horizontal stratum freezing pipe liquid distribution system and method provided by the present invention detects multiple variable parameters of the freezing pipe branch through a multi-sensor data fusion module, and adopts a liquid separation control calculation module based on a fuzzy-PID algorithm, integrating fuzzy logic and PID control, and coordinately controlling according to multiple variable parameters to obtain accurate valve opening adjustment amount to improve liquid separation accuracy and uniformity. At the same time, the valve opening adjustment amount is dynamically adjusted according to the multiple variable parameters updated in real time, which can cope with complex stratum conditions, enhance the continuity of the freezing curtain, and thus improve the freezing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 A block diagram of the carbon dioxide horizontal stratum freezing pipe liquid distribution system provided by the present invention;

[0028] Figure 2 This is a flow chart of the method for dispensing liquid in a horizontal stratum freezing pipe using carbon dioxide provided by the present invention.

[0029] Reference numerals:

[0030] Multi-sensor data fusion module 1, temperature sensor 11, pressure sensor 12, flow meter 12, control valve 2, liquid separation control calculation module 3, data acquisition and input unit 31, fuzzy logic reasoning unit 32, PID correction unit 33, PID control subunit 331, fuzzy-PID composite control subunit 332, central control module 4, carbon dioxide delivery module 5, freezing pipe branch 6. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific illustrations.

[0032] See also Figure 1 , which shows an example of the carbon dioxide horizontal stratum freezing pipe liquid distribution system provided by the present invention.

[0033] As can be seen from the figure, the carbon dioxide horizontal stratum freezing pipe liquid distribution system of this example includes a carbon dioxide delivery module 5, which is connected to several freezing pipe branches 6 respectively, and also includes a multi-sensor data fusion module 1, a control valve 2, a liquid distribution control calculation module 3 and a central control module 4.

[0034] Each freezing pipe branch 6 is equipped with a multi-sensor data fusion module 1 and a control valve 2. The multi-sensor data fusion module 1 is configured to detect the liquid separation state variables of the corresponding freezing pipe branch 6 in real time. The liquid separation state variables include liquid carbon dioxide temperature, pipeline pressure, liquid carbon dioxide flow rate, and formation thermal conductivity. The liquid separation control calculation module 3 is configured to use a fuzzy-PID algorithm to calculate the final valve opening adjustment corresponding to each freezing pipe branch 6 based on the target flow value and liquid separation state variables of each freezing pipe branch 6. The central control module 4 is configured to communicate data with the multi-sensor data fusion module 1, the liquid separation control calculation module 3, and the control valve 2, and adjust the control valve 2 in each freezing pipe branch 6 according to the final valve opening adjustment. This allows for coordinated control based on multiple variable parameters to obtain accurate valve opening adjustment values, thereby improving liquid separation accuracy and uniformity. Furthermore, the valve opening adjustment value is dynamically adjusted based on the real-time updated feedback of the multiple variable parameters, which can cope with complex formation conditions, enhance the continuity of the freezing curtain, and improve the freezing effect.

[0035] The carbon dioxide delivery module 5 is connected to a plurality of freezing pipe branches 6 , and liquid carbon dioxide is injected into each freezing pipe branch 6 , so that the liquid carbon dioxide absorbs heat and vaporizes to form a freezing curtain in the freezing pipe branch 6 .

[0036] In order to accurately control the flow rate of liquid carbon dioxide injected into each freezing pipe branch 6 by the carbon dioxide delivery module 5 and improve the freezing effect, the carbon dioxide delivery module 5 is connected to each freezing pipe branch 6 through the carbon dioxide delivery main pipe, and each freezing pipe branch 6 is provided with a multi-sensor data fusion module 1 and a control valve 2, so that the multi-sensor data fusion module 1 can detect the liquid separation state variables in the corresponding freezing pipe branch 6 in real time, and provide adjustment parameters for the corresponding freezing pipe branch 6 to accurately adjust the opening of the control valve 2, thereby ensuring that the liquid carbon dioxide flow rate in the corresponding freezing pipe branch 6 can effectively enhance the continuity of the freezing curtain and improve the freezing effect.

[0037] Furthermore, the multi-sensor data fusion module 1 includes a temperature sensor 11, a pressure sensor 12 and a flow meter 12, so that the temperature sensor 11, the pressure sensor 12 and the flow meter 12 can respectively detect the liquid carbon dioxide temperature, the pipeline pressure and the liquid carbon dioxide flow in the corresponding freezing pipe branch 6 in real time.

[0038] As a preferred setting scheme, for each freezing pipe branch 6, the temperature sensor 11 is set at the branch entrance, the pressure sensor 12 is set 0.5m downstream of the temperature sensor 11, the flow meter 12 is set 1m downstream of the pressure sensor 12, and the control valve 2 corresponding to the freezing pipe branch 6 is set 0.3m downstream of the flow meter 12.

[0039] In this way, the multi-sensor data fusion module 1 is arranged in the order of "temperature → pressure → flow → valve", which can ensure the timing of data collection. For example, the temperature sensor 11 first detects the initial temperature state of the liquid carbon dioxide, the pressure sensor 12 captures the change in flow resistance and obtains the pipeline pressure, and the flow meter 13 obtains the real-time liquid carbon dioxide flow, so that the control valve 2 can be accurately adjusted according to the data of the first three, forming a "detection-adjustment" closed loop, which can effectively improve the liquid distribution accuracy.

[0040] At the same time, the multi-sensor data fusion module 1 can also detect the formation thermal conductivity of the corresponding freezing pipe branch 6 in real time, thereby obtaining the liquid separation state variable of the freezing pipe branch 6, and feeding it back to the liquid separation control calculation module 3, providing multiple variable parameters for the subsequent adjustment of the control valve 2 of the freezing pipe branch 6.

[0041] As a preferred arrangement, heat flux sensors and temperature gradient probes are installed at radial intervals of 10 cm on the outer wall of the freezing pipe branch 6 to directly detect the heat flux density and temperature gradient of the freezing pipe branch 6. The formation thermal conductivity λ is calculated based on Fourier's heat conduction law. The specific calculation is:

[0042] Formation thermal conductivity λ = q / (dT / dx),

[0043] Where q is the heat flux density detected by the heat flux sensor, and dT / dx is the temperature gradient detected by the temperature gradient probe.

[0044] In some embodiments, a constant heat flow can also be injected into the freezing pipe branch 6, and the temperature change curve can be fitted through a transient thermal response test to invert the thermal conductivity of the formation. This method is a conventional technical means in this field and will not be described in detail here.

[0045] In conjunction with this, the liquid separation control calculation module 3 is configured to collect liquid separation state variables in real time, and adopts a fuzzy-PID algorithm, integrating fuzzy logic and PID control, and calculates the final valve opening adjustment amount ΔV corresponding to each freezing pipe branch 6 according to the preset target flow value V0 of each freezing pipe branch 6 and the liquid separation state variable, thereby coordinating and controlling according to multiple variable parameters to ensure the accuracy of the final valve opening adjustment amount ΔV, so as to improve the accuracy and uniformity of liquid separation.

[0046] See also Figure 1 Specifically, the liquid separation control calculation module 3 includes a data acquisition and input unit 31, a fuzzy logic reasoning unit 32 and a PID correction unit 33. The data acquisition and input unit 31, the fuzzy logic reasoning unit 32 and the PID correction unit 33 can cooperate with each other to perform data transmission and processing, respectively realizing the collection, fuzzy processing and PID fusion processing of liquid separation state variables to obtain the final valve opening adjustment amount ΔV.

[0047] Among them, the data acquisition and input unit 31 is configured to collect liquid separation state variables in real time, and preset the target flow value V0 of each freezing pipe branch 6, and input the target flow value V0 and liquid separation state variables into the fuzzy logic reasoning unit 31 and the PID correction unit 32.

[0048] Here, the target flow value V0 of each freezing pipe branch 6 can be preset based on the ground freezing requirement and dynamically adjusted according to the specific application situation and the ground freezing requirement.

[0049] Furthermore, the fuzzy logic reasoning unit 32 is configured to process the liquid separation state variables according to a preset fuzzy rule base to generate a preliminary valve opening adjustment value V fuzzy .

[0050] First, the fuzzy logic reasoning unit 32 performs fuzzification processing on the liquid separation state variables to convert them into fuzzy variables, and generates temperature deviation fuzzy sets, pressure deviation fuzzy sets and flow deviation fuzzy sets respectively, and the membership function adopts triangular or Gaussian distribution.

[0051] As an example, the fuzzy logic reasoning unit 32 defines the liquid carbon dioxide temperature, pipeline pressure and liquid carbon dioxide flow in the liquid separation state variables as temperature deviation ΔT, pressure deviation ΔP and flow deviation ΔF, respectively, and defines the fuzzy set of temperature deviation ΔT as {negative large (NB), negative medium (NM), zero (ZO), positive medium (PM), positive large (PB)}, and the membership function adopts triangular or Gaussian distribution to generate the temperature deviation fuzzy set. The generation schemes of the pressure deviation fuzzy set and the flow deviation fuzzy set are similar and will not be elaborated here.

[0052] In this way, the real-time updated liquid carbon dioxide temperature, pipeline pressure and liquid carbon dioxide flow are mapped to the corresponding temperature deviation fuzzy set, pressure deviation fuzzy set and flow deviation fuzzy set respectively. Through membership function calculation, the membership of the liquid carbon dioxide temperature, pipeline pressure and liquid carbon dioxide flow in the corresponding fuzzy set corresponding to {negative large (NB), negative medium (NM), zero (ZO), positive medium (PM)} can be obtained, thereby converting the precise liquid separation state variables into the membership of the corresponding fuzzy set.

[0053] Next, the fuzzy logic reasoning unit 32 establishes a fuzzy rule base based on the fuzzy variables to generate a fuzzy output set of the valve opening adjustment amount. For example:

[0054] Rule 1: If the temperature deviation ΔT of the freezing pipe branch 6 is too high (ΔT = PB), then the valve opening corresponding to the freezing pipe branch 6 is increased (adjustment amount = PB). The corresponding fuzzy output of the valve opening adjustment amount is adjustment amount = PB.

[0055] Rule 2: If the pressure deviation ΔP of the freezing pipe branch 6 is large (ΔP=PB) and the flow deviation ΔF is low (ΔF=PB), the valve opening is greatly increased (adjustment amount=PB), and the corresponding fuzzy output set of the valve opening adjustment amount is adjustment amount=PB.

[0056] Here, the fuzzy rule base can be adjusted according to the ground freezing requirements and specific application situations.

[0057] In this way, the liquid carbon dioxide temperature, pipeline pressure and liquid carbon dioxide flow rate are respectively substituted into each rule for calculation. Each rule will generate a corresponding fuzzy output collection of the valve opening adjustment amount. The fuzzy logic reasoning unit 32 aggregates the fuzzy output collection of the valve opening adjustment amount of each rule to obtain a single, total fuzzy output collection of the valve opening adjustment amount, which represents all possible values ​​of the liquid separation state variable and its corresponding fuzzy membership.

[0058] Furthermore, the fuzzy logic reasoning unit 32 will perform defuzzification processing on the fuzzy output collection of the valve opening adjustment amount. In this example, the fuzzy logic reasoning unit 32 uses the centroid method to process, for example, calculating the center of area (center of mass) under the membership function curve of the fuzzy output collection of the valve opening adjustment amount, thereby converting the fuzzy output collection of the valve opening adjustment amount into an accurate preliminary valve opening adjustment amount V fuzzy .

[0059] The fuzzy logic reasoning unit 32 thus constructed calculates the preliminary valve opening adjustment value V of each freezing pipe branch 6 by fuzzifying the liquid separation state variables, establishing a fuzzy rule base and defuzzifying the variables. fuzzy .

[0060] Compared with the existing technology that is mostly based on single flow or pressure feedback, the fuzzy logic reasoning unit 32 integrates liquid carbon dioxide temperature, pipeline pressure, liquid carbon dioxide flow and formation thermal conductivity, and processes nonlinear coupling relationships through fuzzy logic, which is more adaptable and can effectively improve liquid distribution accuracy.

[0061] Furthermore, the existing fuzzy logic reasoning mostly uses fixed thresholds. The present fuzzy logic reasoning unit 32 dynamically adjusts the rule weight according to the thermal conductivity of the formation (such as enhancing the influence weight of the temperature deviation ΔT when λ>2.5W / (m·K) and adjusting the fuzzy rule) to improve the adaptability to complex formations.

[0062] In order to improve the adjustment accuracy of the control valve 2 and ensure the accuracy of liquid separation, the liquid distribution system also includes a PID correction unit 33. The PID correction unit 33 is configured to adjust the initial valve opening value V based on the target flow value V0 of each freezing pipe branch 6 and the liquid separation state variable. fuzzy Perform fusion calculation and output the final valve opening adjustment amount ΔV.

[0063] See also Figure 1 Specifically, the PID correction unit 33 includes a PID control subunit 331, which can calculate the PID valve opening adjustment value V based on the target flow value V0. PID , ensuring the steady-state accuracy and stability of the valve opening.

[0064] As an example, the PID control subunit 331 first performs an error calculation, and obtains the liquid separation deviation e(t) based on the target flow value V0 and the actual flow value, that is, the liquid carbon dioxide flow rate in the liquid separation state variable. The liquid separation deviation e(t) = target flow value V0 - liquid carbon dioxide flow rate.

[0065] Furthermore, the PID control subunit 331 performs proportional, integral and differential operations based on the liquid dispensing deviation e(t).

[0066] The proportional term (P) is: K p ×e(t), which can quickly respond to the current detection deviation;

[0067] The integral term (I) is: K i ×e(t), which can eliminate steady-state errors;

[0068] The differential term (D) is: K d ×e(t), which can suppress overshoot and oscillation.

[0069] Among them, K p , K i and K d are PID parameters, which can be optimized according to the Ziegler-Nichols method or genetic algorithm to ensure system stability and speed.

[0070] In this way, the PID valve opening adjustment value V can be obtained based on the proportional term, integral term and differential term. PID ,

[0071] V PID =K p ×e(t)+K i ×e(t)+K d ×e(t).

[0072] The PID control subunit 331 thus obtains the PID valve opening adjustment value V through PID calculation. PID , which can eliminate errors and ensure the steady-state accuracy and stability of the valve opening.

[0073] Furthermore, the PID correction unit 33 also includes a fuzzy-PID composite control subunit 332, which can adjust the PID valve opening V PID and the initial valve opening adjustment V fuzzy Perform fusion calculation to obtain the final valve opening adjustment amount ΔV.

[0074] As an example, the final valve opening adjustment ΔV=α+β×V PID ,

[0075] Among them, α and β are the initial valve opening adjustment amount V fuzzy and valve opening adjustment V PID The dynamic weight coefficients, in this example, are α=0.6, β=0.4. α and β can also be adaptively adjusted according to the formation thermal conductivity and formation complexity. For example, if the formation thermal conductivity changes dramatically (such as groundwater flow), α is increased to enhance the flexibility of the fuzzy logic reasoning unit 32.

[0076] Furthermore, the fuzzy-PID composite control subunit 332 also performs target optimization with minimizing the liquid distribution deviation and system energy consumption as the objective function to improve the reliability of the liquid distribution system.

[0077] As an example,

[0078] Among them, w1 and w2 are weight coefficients, usually 0.7 and 0.3, which can be adaptively adjusted according to the formation thermal conductivity and formation complexity. ΔF i is the flow deviation of the i-th freezing pipe branch, E i is the energy consumption of the i-th freezing pipe branch, which is linearly related to the opening ΔV of the control valve 2: E i =k·|ΔV|, the energy consumption of the i-th freezing pipe branch is proportional to the final valve opening adjustment amount ΔV corresponding to the i-th freezing pipe branch.

[0079] In this way, the Pareto optimality is achieved between flow control accuracy (ΔF) and energy saving (E), which can effectively improve the energy saving of the liquid distribution system compared with the traditional PID algorithm calculation.

[0080] Therefore, the PID correction unit 33 cooperates with the PID control subunit 331 and the fuzzy-PID composite control subunit 332 to perform PID calculations of the valve opening adjustment amount respectively, and integrates them with the preliminary valve opening adjustment amount to obtain the accurate final valve opening adjustment amount ΔV, thereby effectively improving the liquid separation accuracy.

[0081] Compared with the fuzzy reasoning and PID algorithm in the existing technology, the PID correction unit 33 introduces the thermal conductivity of the formation to dynamically integrate fuzzy reasoning and PID, which can effectively solve the problem of discontinuity of freezing curtain in heterogeneous formations, improve the measured freezing uniformity in sandstone-clay interlaced formations, and reduce energy consumption.

[0082] In conjunction with this, the central control module 4 can collect the final valve opening adjustment amount ΔV of each freezing pipe branch 6 in real time, and accurately adjust the opening of the control valve 2 of the freezing pipe branch 6 accordingly, thereby adjusting the flow rate of liquid carbon dioxide injected into the freezing pipe branch 6 by the carbon dioxide delivery module 5, improving the liquid separation accuracy and enhancing the continuity of the freezing curtain.

[0083] Preferably, the control valve 2 is composed of an existing high-precision electric regulating valve to ensure that the response time of the control valve 2 is ≤ 0.1 seconds, which can quickly meet the final valve opening adjustment amount ΔV and improve the liquid separation efficiency.

[0084] In this way, after the opening of the control valve 2 is adjusted according to the final valve opening adjustment amount ΔV, the liquid separation state in the corresponding freezing pipe branch will be updated, and the multi-sensor data fusion module 1 will update the liquid separation state variable in real time and feed it back to the liquid separation control calculation module 2 to calculate the new final valve opening adjustment amount ΔV, and then adjust the opening of the control valve 2 accordingly, thus forming a "collection → calculation → execution → feedback" closed loop to ensure liquid separation uniformity and system stability.

[0085] In this example, the central control module 4 controls the liquid separation control calculation module 3 to calculate the final valve opening adjustment amount ΔV every 0.5 seconds to ensure that the detection cycle of the liquid separation control calculation module 3 and the multi-sensor data fusion module 1 and the response of the control valve 2 match, and effectively eliminate static errors to ensure the accuracy of the final valve opening adjustment amount ΔV.

[0086] Furthermore, the central control module 4 also includes a redundant unit, which is configured to detect the working status of the multi-sensor data fusion module 1 in each freezing pipe branch 6, and when an abnormality occurs in the multi-sensor data fusion module 1 of the i-th freezing pipe branch, the historical liquid separation state variable interpolation corresponding to the i-th freezing pipe branch or the average of the liquid separation state variables of the remaining freezing pipe branches is used as the liquid separation state variable compensation value of the i-th freezing pipe branch, and the final valve opening adjustment amount ΔV of the i-th freezing pipe branch is calculated simultaneously to ensure the reliability of this liquid distribution system.

[0087] This constitutes the carbon dioxide horizontal stratum freezing pipe liquid distribution system provided by the present invention.

[0088] The present invention also provides a method for dispensing liquid in a carbon dioxide horizontal stratum freezing pipe, based on the carbon dioxide horizontal stratum freezing pipe dispensing system composed of the above scheme, combined with Figure 1 and Figure 2 , this liquid preparation method comprises:

[0089] First, a multi-sensor data fusion module 1 and a control valve 2 are installed in each freezing pipe branch 6. The multi-sensor data fusion module 1 detects the liquid separation state variables of the corresponding freezing pipe branch 6 in real time to obtain the liquid carbon dioxide temperature, pipeline pressure, liquid carbon dioxide flow rate and formation thermal conductivity.

[0090] Furthermore, the liquid separation control calculation module 3 collects the liquid separation state variables and uses the fuzzy-PID algorithm to calculate the final valve opening adjustment amount ΔV corresponding to each freezing pipe branch according to the target flow value V0 of each freezing pipe branch 6 and the liquid separation state variables.

[0091] At the same time, the central control module 4 adjusts the control valve 2 in each freezing pipe branch 6 according to the final valve opening adjustment amount ΔV. The multi-sensor data fusion module 1 updates the liquid separation state variables in real time and feeds back to the liquid separation control calculation module 3 to form a "collection → calculation → execution → feedback" closed loop to ensure liquid separation uniformity and system stability.

[0092] The carbon dioxide horizontal stratum freezing pipe liquid distribution system and method provided by the present invention collects multiple variable parameters of the freezing pipe branch 6 through the cooperation of a multi-sensor data fusion module 1, a control valve 2, a liquid separation control calculation module 3 and a central control module 4, and based on a fuzzy-PID algorithm, coordinates and controls the multiple variable parameters to obtain an accurate valve opening adjustment amount to improve the liquid separation accuracy and uniformity. At the same time, the valve opening adjustment amount is dynamically adjusted according to the multiple variable parameters updated in real time, which can cope with complex stratum conditions, enhance the continuity of the freezing curtain, and thus improve the freezing effect.

[0093] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A carbon dioxide horizontal stratum freezing pipe liquid distribution system, comprising a carbon dioxide delivery module, wherein the carbon dioxide delivery module is respectively connected to a plurality of freezing pipe branches, characterized in that: It also includes multi-sensor data fusion module, control valve, liquid separation control calculation module and central control module. Each freezing pipe branch is provided with a multi-sensor data fusion module and a control valve. The multi-sensor data fusion module is configured to detect the liquid separation state variables of the corresponding freezing pipe branch in real time. The liquid separation state variables include liquid carbon dioxide temperature, pipeline pressure, liquid carbon dioxide flow rate and formation thermal conductivity. The liquid separation control calculation module is configured to use a fuzzy-PID algorithm to calculate the final valve opening adjustment corresponding to each freezing pipe branch according to the target flow value of each freezing pipe branch and the liquid separation state variable. The central control module is configured to transmit data with the multi-sensor data fusion module, the liquid separation control calculation module and the control valve, and adjust the control valve in each freezing pipe branch according to the final valve opening adjustment amount.

2. The carbon dioxide horizontal stratum freezing pipe liquid distribution system according to claim 1 is characterized in that: The multi-sensor data fusion module includes a temperature sensor, a pressure sensor and a flow meter.

3. The carbon dioxide horizontal stratum freezing pipe liquid distribution system according to claim 1 is characterized in that: The liquid separation control calculation module includes a data acquisition and input unit, a fuzzy logic reasoning unit and a PID correction unit. The data acquisition and input unit is configured to transmit the target flow value of each freezing pipe branch and the liquid separation state variables collected in real time to the fuzzy logic reasoning unit and the PID correction unit. The fuzzy logic reasoning unit is configured to process the liquid separation state variables according to a preset fuzzy rule base to generate a preliminary valve opening adjustment amount. The PID correction unit is configured to perform a fusion operation on the preliminary valve opening adjustment amount based on the target flow value and the liquid separation state variables to output the final valve opening adjustment amount.

4. The carbon dioxide horizontal stratum freezing pipe liquid distribution system according to claim 3 is characterized in that: The fuzzy logic reasoning unit performs fuzzification processing on the liquid separation state variables to convert them into fuzzy variables, and generates temperature deviation fuzzy sets, pressure deviation fuzzy sets and flow deviation fuzzy sets respectively. The membership function adopts triangular or Gaussian distribution. Then, a fuzzy rule base is established based on the fuzzy variables to generate a fuzzy output collection of valve opening adjustment amount. Finally, the center of gravity method is used to convert the fuzzy output into a preliminary valve opening adjustment amount.

5. The carbon dioxide horizontal stratum freezing pipe liquid distribution system according to claim 4 is characterized in that: The PID correction unit includes a PID control subunit, which calculates the liquid separation deviation based on the target flow value and the liquid carbon dioxide flow in the liquid separation state variable, and performs proportional, integral and differential operations based on the liquid separation deviation to output the PID valve opening adjustment amount.

6. The carbon dioxide horizontal stratum freezing pipe liquid distribution system according to claim 5, characterized in that: The PID correction unit also includes a fuzzy-PID composite control subunit, which performs weighted fusion on the preliminary valve opening adjustment amount and the PID valve opening adjustment amount, and takes minimizing the liquid separation deviation and system energy consumption as the objective function to obtain the final valve opening adjustment amount and transmit it to the central control module.

7. The carbon dioxide horizontal stratum freezing pipe liquid distribution system according to claim 6, characterized in that: The central control module controls the liquid separation control calculation module to calculate the final valve opening adjustment amount every 0.5 seconds.

8. The carbon dioxide horizontal stratum freezing pipe liquid distribution system according to claim 7, characterized in that: The central control module includes a redundant unit, which can use the historical liquid separation state variable interpolation corresponding to the i-th freezing pipe branch or the average of the liquid separation state variables of the remaining freezing pipe branches as the liquid separation state variable compensation value of the i-th freezing pipe branch when the multi-sensor data fusion module of the i-th freezing pipe branch is abnormal.

9. A method for preparing liquid for a horizontal carbon dioxide freezing pipe, characterized in that: Based on the carbon dioxide horizontal stratum freezing pipe liquid dispensing system according to any one of claims 1 to 8, the liquid dispensing method comprises: A multi-sensor data fusion module and a control valve are installed in each freezing pipe branch. The multi-sensor data fusion module detects the liquid separation state variables of the corresponding freezing pipe branch in real time. The liquid separation state variables include liquid carbon dioxide temperature, pipeline pressure, liquid carbon dioxide flow rate, and formation thermal conductivity. The liquid separation control calculation module collects the liquid separation state variables and uses a fuzzy-PID algorithm to calculate the final valve opening adjustment corresponding to each freezing pipe branch based on the target flow value and liquid separation state variables of each freezing pipe branch. The central control module adjusts the control valve in each freezing pipe branch according to the final valve opening adjustment amount, and the multi-sensor data fusion module updates the liquid separation state variable in real time and feeds it back to the liquid separation control calculation module.

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