Method and system for heat preservation of filling pipeline in cold region based on carbon dioxide mineralization heat release

Abstract

This invention discloses a method and system for heat preservation of backfill pipelines in cold regions based on the exothermic reaction of carbon dioxide mineralization. The heat preservation method includes the following steps: conducting CO2 mineralization kinetic experiments on multi-source mine solid waste backfill materials, measuring the exothermic reaction of mineralization under different parameters, and establishing mathematical models of different parameters and the exothermic reaction of mineralization; constructing a CO2 diffusion law function model of the backfilling stope, obtaining the spatiotemporal variation law of mineralization heat inside the backfilling stope through function calculation, and rationally laying heat exchange pipes according to the degree of heat enrichment; inside the backfilling stope, capturing the heat of CO2 mineralization reaction through heat exchange pipes pre-embedded in the mineralization heat enrichment area of ​​the stope, and heating the ground slurry conveying pipe with the acquired heat through a transfer system; monitoring the temperature change of the slurry in the slurry conveying pipe in real time and judging whether the slurry temperature meets the standard. When the slurry temperature does not meet the standard, the central control system automatically adjusts the flow rate of the heat transfer medium according to the temperature data and forms a closed-loop control for heat preservation.

Description

Technical Field

[0001] This invention relates to the fields of mine backfilling technology and CO2 green treatment technology in cold regions, and particularly to a method and system for heat preservation of backfilling pipelines in cold regions based on the exothermic reaction of carbon dioxide mineralization. Background Technology

[0002] Backfilling mining technology, as an important means of achieving green mining, plays a crucial role in mitigating the disturbance of coal mining to the surface environment and improving the efficiency of mineral resource recovery. However, implementing backfilling mining operations in cold environments faces many severe technical challenges that urgently need to be overcome.

[0003] Cold regions experience harsh climates year-round, with frequent extreme low-temperature events in winter. Under these low-temperature conditions, the rheological properties of materials transported in filling pipelines deteriorate significantly, leading to a substantial increase in the probability of pipeline freezing and blockage. Once freezing and blockage occur, filling operations will be interrupted, disrupting the normal coal production schedule. Currently, traditional technologies for dealing with freezing and blockage in filling pipelines in cold regions mainly include electric heat tracing and steam insulation. Electric heat tracing relies on the conversion of electrical energy into heat energy to maintain pipe temperature; steam insulation utilizes the heat release from the phase change of steam to achieve its insulation function. However, both of these methods have significant drawbacks due to excessive energy consumption, which contradicts the national policy direction of energy conservation and emission reduction.

[0004] CO2 mineralization and sequestration technology, with its ability to permanently solidify industrially emitted CO2 into stable carbonate minerals, has become a key technology for achieving carbon emission reduction strategies and has received widespread attention from academia and industry in recent years. However, in the field of backfilling engineering, this technology has not yet been organically integrated and synergistically operated with the heat recovery process in the backfilling process. It is particularly noteworthy that the introduction of CO2 mineralization reaction into coal-based solid waste backfilling systems is accompanied by a significant exothermic effect, and the valuable heat energy released by this reaction has not been effectively captured and utilized in current processes, resulting in significant energy waste. Therefore, there is an urgent need to develop a method and system for heat preservation of backfilling pipelines in cold regions based on the exothermic effect of carbon dioxide mineralization. Summary of the Invention

[0005] This solution addresses the problems and needs raised above by proposing a method and system for insulation of cold-region filling pipelines based on the exothermic reaction of carbon dioxide mineralization. The above-mentioned technical objectives are achieved by adopting the following technical features, and other technical benefits are also brought about.

[0006] This invention proposes a method for heat preservation of filling pipelines in cold regions based on the exothermic reaction of carbon dioxide mineralization. The filling pipeline includes: a slurry delivery pipe and a heat-conducting medium circulation pipe arranged sequentially from the inside to the outside; wherein a heat exchange pipe connected to the heat-conducting medium circulation pipe is provided in the mineralization reaction zone; the method includes the following steps:

[0007] S10: Conduct CO2 mineralization kinetic experiments on multi-source mine solid waste backfill materials, measure the heat release of mineralization reaction under different parameters, and establish mathematical models of different parameters and mineralization heat release.

[0008] S20: Construct a CO2 diffusion law function model for the backfilled stope, obtain the spatiotemporal variation law of mineralization heat inside the backfilled stope through function calculation, and lay heat exchange pipes reasonably based on the degree of heat enrichment.

[0009] S30: Inside the backfilled stope, CO2 mineralization reaction heat is captured directionally through heat exchange pipes pre-embedded in the mineralization heat enrichment zone of the stope, and the acquired heat is heated to the ground slurry conveying pipe through the heat transfer medium circulation pipe.

[0010] S40: Real-time monitoring of slurry temperature changes in the slurry conveying pipe and determination of whether the slurry temperature meets the standard. When the slurry temperature does not meet the standard, the flow rate of the heat transfer medium in the heat transfer medium circulation pipe is adjusted according to the temperature data to form a closed-loop control for heat preservation.

[0011] In addition, the cold-region filling pipeline insulation method based on carbon dioxide mineralization exothermic according to the present invention may also have the following technical features:

[0012] In one example of the present invention, in step S10, the parameters for measuring the heat of release of the mineralization reaction under different parameters include: temperature, CO2 concentration, solid waste backfill material composition, and time.

[0013] In one example of the present invention, in step S10, a mathematical model is established for different parameters and the heat of mineralization as follows:

[0014] Q(t) = λ(T,S)·[CO2] β ·Φ(t)

[0015] In the formula, λ(T,S) represents the comprehensive reactivity coefficient, which covers the following implicit parameters: the effect of temperature T; the synergistic effect of the solid waste component vector S=(S1,S2,...,Sn); the correction effect of environmental pressure; microenvironmental parameters; [CO2] is the CO2 volume concentration (%), β is the concentration sensitivity index; Φ(t): time decay function.

[0016] In one example of the present invention, in step S20, a CO2 diffusion law function model of the backfilled stope is constructed, and the spatiotemporal variation law of mineralization heat inside the backfilled stope is obtained through function calculation, including the following steps:

[0017] S21: By coupling the CO2 diffusion-reaction equation and the heat conduction equation, the spatiotemporal distribution law of mineralization heat in the backfilled mined area is simulated in real time, and a CO2 diffusion model in the porous backfill body is established, the expression of which is:

[0018]

[0019] In the formula, C is the molar concentration of CO2 in the filling material, t is the reaction time, and D is the molar concentration of CO2 in the filling material. eff The effective diffusion coefficient of CO2 in the filling material, The Laplace operator for CO2 concentration, R min Here, T represents the mineralization reaction rate, and T represents the local temperature of the filling material.

[0020] S22: Based on reaction kinetics, the heat release power q per unit volume is directly derived from the enthalpy change ΔH of the reaction. v Its expression is:

[0021] q v =R min ·(-ΔH)

[0022] In the formula, q v ΔH represents the heat release power per unit volume, and ΔH represents the molar enthalpy change of the mineralization reaction; negative values ​​indicate exothermic reactions.

[0023] S23: q v Embedded as a heat source term in the unsteady heat conduction equation, we obtain:

[0024]

[0025] In the formula, ρ is the density of the filling material, and c is the density of the filling material. p λ is the specific heat capacity of the filling material, T is the temperature of the filling material, t is time, and λ is the time. eff For the effective thermal conductivity of the filling material, For the Laplace operator of the temperature field;

[0026] S24: Solve this equation using the finite volume method, dynamically outputting the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area. v Evolutionary data for (x,y,z,t).

[0027] In one example of the present invention, in step S24, the equation is solved using the finite volume method to dynamically output the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area. v After obtaining the evolution data of (x,y,z,t), the following steps are also included:

[0028] The CO2 diffusion law function model updates the spatial coordinates and duration of the heat-rich area at specified intervals, providing a dynamic optimization basis for the layout of heat exchange pipes. It allows for the rational arrangement of the density of pipe laying, with higher density pipes in areas with dense heat distribution and relatively fewer pipes in areas with less heat distribution.

[0029] In one example of the present invention, in step S30, the CO2 mineralization reaction heat is captured directionally through a heat exchange pipe pre-embedded in the mineralization heat enrichment zone of the stope, specifically including the following:

[0030] Wastewater with a stable pH value in the near-neutral range and controllable dissolved salt content is obtained from underground water after neutralization treatment. No corrosive neutral wastewater from the mine is used as a heat transfer medium.

[0031] Wastewater is injected into the heat exchange pipe through an antifreeze booster pump. When it flows through the high-temperature filling area, it absorbs the heat of the mineralization reaction. The heated neutral wastewater medium is then transported to the ground heat transfer medium circulation pipe through the heat exchange pipe.

[0032] In one example of the present invention, the heat exchange tube is a capillary network structure.

[0033] In one example of the present invention, in step S40, the filling pipeline further includes:

[0034] A temperature sensor is installed inside the slurry conveying pipe and is configured to monitor the temperature of the filling slurry inside the slurry conveying pipe.

[0035] Another objective of this invention is to provide a thermal insulation system for a filling pipeline in cold regions based on the exothermic reaction of carbon dioxide mineralization. The filling pipeline includes: a slurry delivery pipe and a heat-conducting medium circulation pipe arranged sequentially from the inside to the outside, wherein a heat exchange pipe connected to the heat-conducting medium circulation pipe is provided in the mineralization reaction zone; including:

[0036] The mathematical model module is configured to conduct CO2 mineralization kinetic experiments on multi-source mine solid waste backfill materials, measure the heat release of the mineralization reaction under different parameters, and establish mathematical models of different parameters and the heat release of mineralization.

[0037] The pipeline laying module is configured to construct a CO2 diffusion law function model for the filling stope, obtain the spatiotemporal variation law of mineralization heat inside the filling stope through function calculation, and lay heat exchange pipes reasonably according to the degree of heat enrichment.

[0038] The heat acquisition and heating module is configured to capture CO2 mineralization reaction heat in a directional manner through a heat exchange pipe pre-embedded in the mineralization heat enrichment zone of the filling stope, and then heat the ground slurry conveying pipe through a heat-conducting medium circulation pipe.

[0039] The heat judgment and control module is configured to monitor the temperature change of the slurry in the slurry conveying pipe in real time and determine whether the slurry temperature meets the standard. When the slurry temperature does not meet the standard, the flow rate of the heat transfer medium in the heat transfer medium circulation pipe is adjusted according to the temperature data to form a heat preservation closed-loop control.

[0040] In one example of the present invention, the pipe laying module includes:

[0041] The diffusion model building unit is configured to couple the CO2 diffusion-reaction equation with the heat conduction equation to extrapolate the spatiotemporal distribution of mineralization heat within the backfilled mined area in real time, establishing a CO2 diffusion model in the porous backfill body. Its expression is as follows:

[0042]

[0043] In the formula, C is the molar concentration of CO2 in the filling material, t is the reaction time, and D is the molar concentration of CO2 in the filling material. eff The effective diffusion coefficient of CO2 in the filling material, The Laplace operator for CO2 concentration, R min Here, T represents the mineralization reaction rate, and T represents the local temperature of the filling material.

[0044] The heat release power derivation unit is configured to directly derive the heat release power q per unit volume from the reaction enthalpy change ΔH based on reaction kinetics. v Its expression is:

[0045] q v =R min ·(-ΔH)

[0046] In the formula, q v ΔH represents the heat release power per unit volume, and ΔH represents the molar enthalpy change of the mineralization reaction; negative values ​​indicate exothermic reactions.

[0047] The heat source term embedding unit is configured to use q v Embedded as a heat source term in the unsteady heat conduction equation, we obtain:

[0048]

[0049] In the formula, ρ is the density of the filling material, and c is the density of the filling material. p λ is the specific heat capacity of the filling material, T is the temperature of the filling material, t is time, and λ is the time. eff For the effective thermal conductivity of the filling material, For the Laplace operator of the temperature field;

[0050] The temperature and heat release intensity unit is configured to solve the equation using the finite volume method, dynamically outputting the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area. v Evolutionary data for (x,y,z,t).

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. By using waste heat from mineralization reactions to replace traditional electric heat tracing, the heat resources released from the mining area can be maximized, effectively preventing pipeline freezing accidents in cold regions, reducing energy consumption by more than 90%, and achieving green CO2 treatment.

[0053] 2. Significantly reduce energy consumption and costs: By recycling the heat energy from the CO2 mineralization reaction of mine solid waste to heat the filling pipeline, operating costs can be reduced by more than 60% compared with traditional electric heating or steam insulation methods, reducing dependence on external energy.

[0054] 3. Improve heat recovery efficiency: Based on the mineralization exothermic kinetic model and heat field simulation technology, optimize the layout of heat exchange tubes to improve heat capture efficiency by more than 40%, and achieve precise heat recovery and utilization.

[0055] 4. Enhanced adaptability to extreme environments: The intelligent temperature control system can stably maintain the slurry temperature within a safe range in low-temperature environments, greatly improving the reliability of system operation.

[0056] 5. Achieve dual benefits of CO2 sequestration and energy recovery: While realizing CO2 mineralization, it absorbs the heat generated by the mineralization process, thus possessing dual environmental and economic value of carbon emission reduction and energy reuse.

[0057] 6. Construct a closed-loop green and low-carbon technology system: Form a complete technology chain of "solid waste treatment - CO2 storage - thermal energy utilization" to provide sustainable green and low-carbon solutions for the mining industry and promote the realization of resource recycling and carbon neutrality goals.

[0058] The preferred embodiments of the invention will be described in more detail below with reference to the accompanying drawings, so as to facilitate an understanding of the features and advantages of the invention. Attached Figure Description

[0059] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. The drawings are merely illustrative of some embodiments of the present invention and are not intended to limit the scope of the present invention to all embodiments.

[0060] Figure 1 A flowchart of a cold-region filling pipeline insulation method based on carbon dioxide mineralization exothermic according to an embodiment of the present invention;

[0061] Figure 2 This is a structural diagram of a ground filling pipeline according to an embodiment of the present invention;

[0062] Figure 3 This is a schematic diagram of the insulation method for filling pipelines according to an embodiment of the present invention.

[0063] List of reference numerals in the attached diagram:

[0064] Filling pipeline 10;

[0065] Slurry conveying pipe 1;

[0066] Filler slurry 11;

[0067] Heat transfer medium circulation pipe 2;

[0068] Thermal medium 21;

[0069] Insulation layer 3;

[0070] Temperature sensor 4;

[0071] Heat exchange tube 5. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0073] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0074] According to a first aspect of the present invention, a method for heat insulation of cold-region filling pipelines based on the exothermic reaction of carbon dioxide mineralization is provided, such as... Figures 1 to 3 As shown, it is applied to a filling pipeline 10, which includes: a slurry conveying pipe 1 and a heat-conducting medium circulation pipe 2 arranged sequentially from the inside to the outside, wherein a heat exchange pipe 5 connected to the heat-conducting medium circulation pipe 2 is provided in the mineralization reaction zone; the process includes the following steps:

[0075] S10: Conduct CO2 mineralization kinetic experiments on multi-source mine solid waste backfill materials, measure the heat release of mineralization reaction under different parameters, and establish mathematical models of different parameters and mineralization heat release.

[0076] S20: Construct a CO2 diffusion law function model for the backfilled stope, obtain the spatiotemporal variation law of mineralization heat inside the backfilled stope through function calculation, and lay heat exchange pipes 5 reasonably based on the degree of heat enrichment;

[0077] S30: Inside the backfilled stope, the heat of CO2 mineralization reaction is captured in a directional manner through the heat exchange pipe 5 pre-embedded in the mineralization heat enrichment area of ​​the stope, and the heat obtained is heated to the ground slurry conveying pipe 1 through the heat transfer medium circulation pipe 2.

[0078] S40: Real-time monitoring of slurry temperature changes in slurry conveying pipe 1 and determination of whether the slurry temperature meets the standard. When the slurry temperature does not meet the standard, the flow rate of heat transfer medium 21 in heat transfer medium circulation pipe 2 is adjusted according to the temperature data to form a heat preservation closed-loop control.

[0079] This insulation method utilizes waste heat from mineralization reactions to replace traditional electric heat tracing, maximizing the utilization of heat resources in the mining area, effectively preventing pipeline freezing accidents in cold regions, reducing energy consumption by more than 90%, and achieving green CO2 treatment.

[0080] This insulation method significantly reduces energy consumption and costs: by recovering and utilizing the heat energy from the CO2 mineralization reaction of mine solid waste to heat the filling pipeline 10, compared with traditional electric heat tracing or steam insulation methods, it can reduce operating costs by more than 60% and reduce dependence on external energy.

[0081] This insulation method improves heat recovery efficiency: based on the mineralization exothermic kinetic model and heat field simulation technology, the layout of heat exchange tube 5 is optimized, which improves the heat capture efficiency by more than 40%, and realizes precise heat recovery and utilization.

[0082] This insulation method enhances adaptability to extreme environments: the intelligent temperature control system can stably maintain the slurry temperature within a safe range in low-temperature environments, significantly improving the reliability of system operation.

[0083] This insulation method achieves the dual benefits of CO2 sequestration and energy recovery: it absorbs the heat generated during CO2 mineralization, thus possessing both environmental and economic value in terms of carbon emission reduction and energy reuse.

[0084] This insulation method constructs a closed loop of green and low-carbon technology: forming a complete technology chain of "solid waste treatment - CO2 storage - thermal energy utilization", providing sustainable green and low-carbon solutions for the mining industry and promoting the realization of resource recycling and carbon neutrality goals.

[0085] This insulation method deeply integrates CO2 mineralization and storage technology with coal-based solid waste backfilling engineering, significantly reducing the risk of freezing and blockage in backfilling pipelines by effectively recovering and utilizing the exothermic resources from the reaction. This breakthrough in system and method not only addresses a key technological need for green and efficient mining in cold regions within the coal industry, but also has profound strategic significance for promoting the sustainable development of the coal industry and enhancing its overall competitiveness.

[0086] It should be noted that the insulation system includes a surface pipeline system and an underground heat exchange system. The surface pipeline system includes a temperature sensor 4, a central control system, two heat transfer medium circulation pipes, and a slurry delivery pipe 1. The temperature sensor 4 monitors the temperature of the slurry delivery pipe 1 in real time and transmits the temperature information to the central control system, which adjusts the flow rate of the heat transfer medium circulation pipe 2 based on the temperature information. The underground heat exchange system includes a CO2 injection device and a heat exchange pipe 5. The heat exchange pipe 5 is located in the mineralization reaction zone and is connected to the two heat transfer medium circulation pipes. The injection of CO2 into the well by the CO2 injection device triggers the mineralization reaction of the filling material, thereby capturing heat in the heat exchange pipe 5. The heat exchange pipe 5 is connected to the two heat transfer medium circulation pipes. The central control system controls the flow rate of the heat transfer medium circulation pipes 2 to change the heat exchange efficiency of the heat exchange pipe 5. The heat exchange pipe 5 transfers heat to the heat transfer medium circulation pipes 2, thereby heating the slurry delivery pipe 1.

[0087] A network of temperature sensors 4 is installed along the pipeline to monitor the temperature changes of the slurry in real time. The central control system automatically adjusts the flow rate of the heat transfer medium 21 based on the temperature data. The ground filling pipeline 10 adopts a three-layer insulation pipeline structure: slurry delivery pipe 1, heat transfer medium circulation pipe 2, and insulation layer 3. The slurry delivery pipe 1 is filled with slurry 11, the outer heat transfer medium circulation pipe 2 contains heat transfer medium 21, and the outermost layer is composed of insulation layer 3. The system feeds back the temperature signal to the downhole CO2 injection device and dynamically optimizes the mineralization heat release intensity by changing the CO2 injection pressure or flow rate, forming a closed-loop insulation control.

[0088] In one example of the present invention, in step S10, the parameters for measuring the heat of release of the mineralization reaction under different parameters include: temperature, CO2 concentration, solid waste backfill material composition, and time.

[0089] In one example of the present invention, in step S10, a mathematical model is established for different parameters and the heat of mineralization as follows:

[0090] Q(t) = λ(T,S)·[CO2] β ·Φ(t)

[0091] In the formula, λ(T,S) represents the comprehensive reactivity coefficient, which covers the following implicit parameters: the effect of temperature T; the synergistic effect of the solid waste component vector S=(S1,S2,...,Sn) (such as Ca / Mg content, specific surface area, crystal defect density, etc.); the correction effect of environmental pressure; microenvironmental parameters (porosity, humidity, etc.); [CO2] is the CO2 volume concentration (%), β is the concentration sensitivity index; Φ(t): time decay function, characterizing the change of exothermic rate in the reaction process.

[0092] In one example of the present invention, in step S20, a CO2 diffusion law function model of the backfilled stope is constructed, and the spatiotemporal variation law of mineralization heat inside the backfilled stope is obtained through function calculation, including the following steps:

[0093] S21: By coupling the CO2 diffusion-reaction equation and the heat conduction equation, the spatiotemporal distribution law of mineralization heat in the backfilled mined area is simulated in real time, and a CO2 diffusion model in the porous backfill body is established, the expression of which is:

[0094]

[0095] In the formula, C is the molar concentration of CO2 in the filling material, t is the reaction time, and D is the molar concentration of CO2 in the filling material. eff The effective diffusion coefficient of CO2 in the filling material, The Laplace operator for CO2 concentration, R min Here, T represents the mineralization reaction rate, and T represents the local temperature of the filling material.

[0096] S22: Based on reaction kinetics, the heat release power q per unit volume is directly derived from the enthalpy change ΔH of the reaction. v Its expression is:

[0097] q v =R min ·(-ΔH)

[0098] In the formula, q v ΔH represents the heat release power per unit volume, and ΔH represents the molar enthalpy change of the mineralization reaction; negative values ​​indicate exothermic reactions.

[0099] S23: q v Embedded as a heat source term in the unsteady heat conduction equation, we obtain:

[0100]

[0101] In the formula, ρ is the density of the filling material, and c is the density of the filling material. p λ is the specific heat capacity of the filling material, T is the temperature of the filling material, t is time, and λ is the time. eff For the effective thermal conductivity of the filling material, For the Laplace operator of the temperature field;

[0102] S24: Solve this equation using the finite volume method, dynamically outputting the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area. v Evolutionary data for (x,y,z,t).

[0103] In one example of the present invention, in step S24, the equation is solved using the finite volume method to dynamically output the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area. v After obtaining the evolution data of (x,y,z,t), the following steps are also included:

[0104] The CO2 diffusion law function model updates the spatial coordinates and duration of the heat-rich area every specified time (e.g., 30 minutes), providing a dynamic optimization basis for the layout of heat exchange pipe 5, and reasonably arranging the density of pipe laying. In areas with dense heat distribution, pipes with higher density are laid, and vice versa.

[0105] In one example of the present invention, in step S30, the CO2 mineralization reaction heat is captured directionally by a heat exchange pipe 5 pre-embedded in the mineralization heat enrichment zone of the mining area, specifically including the following:

[0106] Wastewater with a stable pH value in the near-neutral range and controllable dissolved salt content is obtained from underground water after neutralization treatment. The non-corrosive neutral wastewater from the mine is used as a heat transfer medium 21 to eliminate the risk of corrosion to the metal pipe network.

[0107] Wastewater is injected into heat exchange pipe 5 through antifreeze booster pump. When it flows through the high-temperature filling area, it absorbs the heat of mineralization reaction. The heated neutral wastewater medium is then transported to the ground heat transfer medium circulation pipe 2 through heat exchange pipe 5.

[0108] In one example of the present invention, the heat exchange tube 5 is a capillary network structure;

[0109] The heat exchange tube 5 adopts a capillary network structure, with its extended contact surface directly bonded to the solidified filling body, efficiently conducting the heat energy released by the reaction. The circulation system uses non-corrosive neutral wastewater from the mine as the heat transfer medium 21. This wastewater originates from underground water flow and is obtained after neutralization treatment. Its pH value is stable in the near-neutral range, and the content of dissolved salts is controllable, eliminating the risk of corrosion to the metal pipe network. The wastewater is injected into the capillary network of the heat exchange unit through an antifreeze booster pump. When flowing through the high-temperature filling area, it absorbs the heat of the mineralization reaction. The heated neutral wastewater medium is then transported to the surface transfer system through insulated pipes. By designing the heat exchange tube 5 as a capillary network structure, the contact area with the mineralization reaction zone can be greatly increased, thereby improving the efficiency of heat acquisition.

[0110] In one example of the present invention, in step S40, the filling pipeline 10 further includes:

[0111] Temperature sensor 4 is located inside the slurry conveying pipe 1 and is configured to monitor the temperature of the filling slurry 1111 inside the slurry conveying pipe 1.

[0112] A temperature sensor network 4 is installed inside the slurry delivery pipe 1. For example, sensor components can be spaced out along the circumferential direction of the slurry delivery pipe 1 and along the length direction of the slurry delivery pipe 1 to monitor the temperature change of the slurry in real time. The central control system automatically adjusts the flow rate of the heat transfer medium 21 according to the temperature data. The surface filling pipeline 10 adopts the following structure: slurry delivery pipe 1, heat transfer medium circulation pipe 2, and insulation layer 3. The slurry delivery pipe 1 is filled with slurry 11, the outer heat transfer medium circulation pipe 2 contains heat transfer medium 21, and the outermost layer is composed of insulation layer 3. The system feeds back the temperature signal to the downhole CO2 injection device and dynamically optimizes the mineralization heat release intensity by changing the CO2 injection pressure or flow rate, forming a closed-loop control for insulation.

[0113] According to a second aspect of the present invention, a cold-region filling pipeline insulation system based on carbon dioxide mineralization exothermic reaction is provided, wherein the filling pipeline 10 includes: a slurry conveying pipe 1 and a heat-conducting medium circulation pipe 2 arranged sequentially from the inside to the outside, wherein a heat exchange pipe 5 connected to the heat-conducting medium circulation pipe 2 is provided in the mineralization reaction zone; including:

[0114] The mathematical model module is configured to conduct CO2 mineralization kinetic experiments on multi-source mine solid waste backfill materials, measure the heat release of the mineralization reaction under different parameters, and establish mathematical models of different parameters and the heat release of mineralization.

[0115] The pipeline laying module is configured to construct a CO2 diffusion law function model for the filling stope, obtain the spatiotemporal variation law of mineralization heat inside the filling stope through function calculation, and lay heat exchange pipes 5 reasonably according to the degree of heat enrichment.

[0116] The heat acquisition and heating module is configured to capture CO2 mineralization reaction heat in a directional manner through a heat exchange pipe 5 pre-embedded in the mineralization heat enrichment zone of the filling stope, and heat the ground slurry conveying pipe 1 through the heat transfer medium circulation pipe 2.

[0117] The heat judgment and control module is configured to monitor the temperature change of the slurry in the slurry conveying pipe 1 in real time and determine whether the slurry temperature meets the standard. When the slurry temperature does not meet the standard, the flow rate of the heat transfer medium 21 in the heat transfer medium circulation pipe 2 is adjusted according to the temperature data to form a heat preservation closed-loop control.

[0118] This insulation system utilizes waste heat from mineralization reactions to replace traditional electric heat tracing, maximizing the utilization of heat resources in the mining area, effectively preventing pipeline freezing accidents in cold regions, reducing energy consumption by more than 90%, and achieving green CO2 treatment.

[0119] This insulation system significantly reduces energy consumption and costs: by recovering and utilizing the heat energy from the CO2 mineralization reaction of mine solid waste to heat the filling pipeline 10, it can reduce operating costs by more than 60% compared with traditional electric heat tracing or steam insulation methods, and reduce dependence on external energy.

[0120] This insulation system improves heat recovery efficiency: based on the mineralization exothermic kinetic model and heat field simulation technology, the layout of heat exchange tube 5 is optimized, which increases the heat capture efficiency by more than 40%, and realizes precise heat recovery and utilization.

[0121] This insulation system enhances adaptability to extreme environments: the intelligent temperature control system can stably maintain the slurry temperature within a safe range in low-temperature environments, significantly improving the reliability of system operation.

[0122] This insulation system achieves the dual benefits of CO2 sequestration and energy recovery: it absorbs the heat generated during CO2 mineralization, thus possessing both environmental and economic value in terms of carbon emission reduction and energy reuse.

[0123] This insulation system constructs a closed loop of green and low-carbon technology: forming a complete technology chain of "solid waste treatment - CO2 storage - thermal energy utilization", providing sustainable green and low-carbon solutions for the mining industry and promoting the realization of resource recycling and carbon neutrality goals.

[0124] This insulation system deeply integrates CO2 mineralization and storage technology with coal-based solid waste backfilling engineering, significantly reducing the risk of freezing and blockage in backfilling pipelines by effectively recovering and utilizing the exothermic resources from the reaction. This breakthrough in system and method not only addresses a key technological need for green and efficient mining in cold regions within the coal industry, but also has profound strategic significance for promoting the sustainable development of the coal industry and enhancing its overall competitiveness.

[0125] In one example of the present invention, the pipe laying module includes:

[0126] The diffusion model building unit is configured to couple the CO2 diffusion-reaction equation with the heat conduction equation to extrapolate the spatiotemporal distribution of mineralization heat within the backfilled mined area in real time, establishing a CO2 diffusion model in the porous backfill body. Its expression is as follows:

[0127]

[0128] In the formula, C is the molar concentration of CO2 in the filling material, t is the reaction time, and D is the molar concentration of CO2 in the filling material. eff The effective diffusion coefficient of CO2 in the filling material, The Laplace operator for CO2 concentration, R min Here, T represents the mineralization reaction rate, and T represents the local temperature of the filling material.

[0129] The heat release power derivation unit is configured to directly derive the heat release power q per unit volume from the reaction enthalpy change ΔH based on reaction kinetics. v Its expression is:

[0130] q v =R min ·(-ΔH)

[0131] In the formula, q v ΔH represents the heat release power per unit volume, and ΔH represents the molar enthalpy change of the mineralization reaction; negative values ​​indicate exothermic reactions.

[0132] The heat source term embedding unit is configured to use q v Embedded as a heat source term in the unsteady heat conduction equation, we obtain:

[0133]

[0134] In the formula, ρ is the density of the filling material, and c is the density of the filling material. p λ is the specific heat capacity of the filling material, T is the temperature of the filling material, t is time, and λ is the time. eff For the effective thermal conductivity of the filling material, For the Laplace operator of the temperature field;

[0135] The temperature and heat release intensity unit is configured to solve the equation using the finite volume method, dynamically outputting the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area. v Evolutionary data for (x,y,z,t).

[0136] It should be noted that the cold-region filling pipeline insulation system based on carbon dioxide mineralization exothermic of the present invention can also perform any of the processes described in the previously described cold-region filling pipeline insulation method based on carbon dioxide mineralization exothermic, and the specific details are not repeated here.

[0137] Specific Cases

[0138] The implementation of this invention is illustrated through a backfilling project example in a coal mine in Inner Mongolia. The steps are as follows:

[0139] Step 1: Conduct CO2 mineralization kinetics experiments on multi-source solid waste backfill materials. A mixed sample of coal gangue, gasification slag, and desulfurization gypsum from a mining backfill station was selected. The effects of temperature, CO2 concentration, and time on the heat release were systematically tested in a high-temperature, high-pressure reactor. Monitoring using a thermocouple array revealed that when the CaO content in the solid waste was 12.5% ​​and the MgO content was 3.2%, the peak heat release power per unit mass occurred at 50℃ and a CO2 concentration of 30%. A mathematical model was established by fitting the experimental data, revealing that humidity exceeding 15% reduces the heat release rate by 18%, and determining the characteristic laws of the concentration sensitivity index β = 1.3 and the time decay function Φ(t) = t^{-0.2}.

[0140] Step 2: Based on the above model, and combining the three-dimensional structure of the mining area and the physical properties of the filling material, the CO2 diffusion-reaction equation and the unsteady-state heat conduction equation are solved in a coupled manner. Dynamic simulation using the finite volume method with a 0.5m cubic mesh shows that 24 hours after CO2 injection, a concentration exceeding 110 W / m³ is formed within a 20-meter radius of the injection port. 3 The high-temperature core area; after 72 hours, the heat migrates to the top, and the heat release intensity in the top 5 meters reaches 85W / m. 3 Based on this, the layout of heat exchange tube 5 was optimized, with a spacing of 0.35 m / m in the core enrichment area, which accounts for 22% of the mining area volume. 2 With increased pipe density, the density in secondary areas is reduced to 0.18 m / m. 2 The edge area is only configured with 0.05m / m 2 Sparse pipes.

[0141] Step 3: Pre-embed a heat exchange system before the filling material solidifies. A DN20 polyethylene capillary network with aluminum fins is embedded 0.8 meters deep into the filling material. Mine water, after neutralization and the addition of a refrigerant, is used as the circulating medium. A variable frequency antifreeze booster pump drives the medium through the enrichment zone. The measured inlet water temperature rises from 8℃ to 32℃. The heated medium is then transported to the surface via a DN150 insulated steel pipe, transferring heat to the outer cavity of the slurry delivery pipe 1.

[0142] Step 4: Install 4 PT100 temperature sensors every 50 meters along the 2-kilometer delivery pipeline, and install viscosity-pressure joint monitoring and freezing / blocking early warning devices at 12 key locations. The central control system dynamically adjusts based on real-time temperature data: when the slurry temperature is below 8℃, the flow rate of the insulating medium is increased by 20%, and the downhole CO2 injection pressure is raised to 1.2MPa to enhance mineralization heat release; when the temperature rises above 15℃, the baseline flow rate is restored. If a viscosity > 2500 cP or a pressure difference > 0.5MPa is detected, the automatic antifreeze injection mechanism is immediately triggered. After implementation, the slurry temperature is maintained at 10-14℃ throughout the -25℃ environment, an increase of more than 12℃ compared to the original system, the CO2 mineralization heat utilization rate reaches 88%, and the risk of freezing / blocking is eliminated.

[0143] This case study, through a closed-loop chain of experimental modeling, dynamic simulation, directional heat capture, and intelligent control, ensures safe transportation in extremely cold environments while saving annual coal-fired heating costs. It forms an integrated "carbon sequestration-heat generation" green transformation template for mines, providing a replicable Chinese solution for resource development in high-altitude and cold regions.

[0144] In a coal mine backfilling project in Inner Mongolia, this technical solution achieved remarkable results. Through a systematic mineralization heat utilization system, test data showed that the heat release efficiency was improved by more than 40% under optimized conditions compared with conventional operating conditions, laying a solid foundation for engineering applications.

[0145] During actual operation, the heat recovery system performed excellently, with heat exchange efficiency remaining stable between 65% and 70%. In frigid environments as low as -30°C, the system successfully maintained the slurry temperature within the ideal range of 10-15°C, completely resolving the freezing and blockage problem. Compared to the original system, energy consumption was reduced by more than 80%, and maintenance costs were reduced by more than 80%.

[0146] This system represents a major breakthrough in the utilization of solid waste resources. Each cubic meter of backfill can simultaneously seal a certain amount of carbon dioxide and consume a considerable proportion of solid waste, making it an effective means of solid waste treatment in mining areas.

[0147] In terms of economic benefits, in addition to directly saving energy costs, it also avoids production losses caused by freezing and blockage, and with the potential carbon trading revenue, the overall economic benefits are significantly improved. The environmental benefits are also reflected in improving the microclimate of the mining area, raising the temperature of the surrounding rock mass by 4-6°C, reducing the maintenance cost of roadways by about 35%, and achieving a water resource recycling rate of over 90%.

[0148] After operational verification, the system demonstrated stable performance under extreme conditions, with an annual heat recovery efficiency decay rate of less than 3%, a temperature control response time of less than 10 minutes, and a near 100% accuracy rate in freezing and blockage early warning. This technology not only solves the problem of slurry transportation in high-altitude and cold regions but also establishes an innovative model integrating solid waste treatment, carbon sequestration, and thermal energy utilization, providing an important demonstration for the green transformation of mines.

[0149] The foregoing description, with reference to preferred embodiments, details the exemplary implementation of the cold-region filling pipeline insulation method and system based on carbon dioxide mineralization exothermics proposed in this invention. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of this invention, and various combinations can be made to the various technical features and structures proposed in this invention without exceeding the protection scope of this invention, which is determined by the appended claims.

Claims

1. A method for heat insulation of cold-region filling pipelines based on the exothermic reaction of carbon dioxide mineralization, characterized in that, The filling pipeline (10) is applied to a filling pipeline (10), which includes a slurry conveying pipe (1) and a heat-conducting medium circulation pipe (2) arranged sequentially from the inside to the outside. A heat exchange pipe (5) connected to the heat-conducting medium circulation pipe (2) is provided in the mineralization reaction zone. The heat preservation method includes the following steps: S10: Conduct CO2 mineralization kinetics experiments on multi-source mine solid waste backfill materials, measure the heat release of the mineralization reaction under different parameters, and establish mathematical models of different parameters and the heat release of mineralization; in step S10, the mathematical models of different parameters and the heat release of mineralization are established as follows: In the formula, λ represents the comprehensive reactivity coefficient, which covers the following implicit parameters: the influence of local temperature T of the filling body; the synergistic effect of solid waste component vector S=(S1,S2,...,Sn); the correction effect of environmental pressure; microenvironmental parameters; [CO2] is the CO2 volume concentration, and β is the concentration sensitivity index; It is a time decay function; S20: Construct a CO2 diffusion law function model for the backfilled stope, calculate the spatiotemporal variation law of mineralization heat inside the backfilled stope through function calculation, and lay heat exchange pipes reasonably according to the degree of heat enrichment (5); specifically including the following steps: S21: By coupling the CO2 diffusion-reaction equation and the heat conduction equation, the spatiotemporal distribution law of mineralization heat in the backfilled mined area is simulated in real time, and a CO2 diffusion model in the porous backfill body is established, the expression of which is: In the formula, C is the molar concentration of CO2 in the filling material, t is the reaction time, and D is the molar concentration of CO2 in the filling material. eff The effective diffusion coefficient of CO2 in the filling material, The Laplace operator for CO2 concentration, R min Here, T represents the mineralization reaction rate, and T represents the local temperature of the filling material. S22: Based on the reaction kinetics, the unit volume exothermic power q is directly derived from the reaction enthalpy change ΔH v The expression is: In the formula, q v ΔH represents the heat release power per unit volume, and ΔH represents the molar enthalpy change of the mineralization reaction; negative values ​​indicate exothermic reactions. S23: q v As the heat source term embedded in the non-steady heat conduction equation, we get: In the formula, For the density of the filling material, c p λ is the specific heat capacity of the filling material, T is the local temperature of the filling material, t is time, and λ is the value of λ. eff For the effective thermal conductivity of the filling material, For the Laplace operator of the temperature field; S24: Solve this equation using the finite volume method, dynamically outputting the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area. v Evolutionary data of (x,y,z,t); S30: Inside the filling stope, CO2 mineralization reaction heat is captured directionally through heat exchange pipes (5) pre-embedded in the mineralization heat enrichment area of ​​the stope, and the heat obtained is heated to the ground slurry conveying pipe (1) through heat transfer medium circulation pipe (2). S40: Real-time monitoring of the temperature change of the slurry in the slurry conveying pipe (1) and determination of whether the slurry temperature meets the standard. When the slurry temperature does not meet the standard, the flow rate of the heat-conducting medium (21) in the heat-conducting medium circulation pipe (2) is adjusted according to the temperature data to form a heat preservation closed-loop control.

2. The method for heat preservation of cold-region filling pipelines based on carbon dioxide mineralization exothermic reaction according to claim 1, characterized in that, In step S10, the parameters for measuring the heat release of the mineralization reaction under different parameters include: temperature, CO2 concentration, solid waste backfill material composition, and time.

3. The method for heat preservation of cold-region filling pipelines based on carbon dioxide mineralization exothermic reaction according to claim 1, characterized in that, In step S24, the equation is solved using the finite volume method, and the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area are dynamically output. v After obtaining the evolution data of (x,y,z,t), the following steps are also included: The CO2 diffusion law function model updates the spatial coordinates and duration of the heat-rich area every specified time interval, providing a dynamic optimization basis for the layout of heat exchange pipes (5), and reasonably arranging the density of pipe laying. In areas with dense heat distribution, pipes with higher density are laid, while in areas with less heat distribution, pipes are relatively reduced.

4. The method for heat preservation of cold-region filling pipelines based on carbon dioxide mineralization exothermic reaction according to claim 1, characterized in that, In step S30, the CO2 mineralization reaction heat is captured directionally through heat exchange pipes (5) pre-embedded in the mineralization heat enrichment zone of the mining area, specifically including the following: Wastewater with a stable pH value in the near-neutral range and controllable dissolved salt content is obtained from underground water after neutralization treatment. No corrosive neutral wastewater from the mine is used as a heat transfer medium (21). Wastewater is injected into the heat exchange pipe (5) through the antifreeze booster pump. When it flows through the high-temperature filling area, it absorbs the heat of mineralization reaction. The heated neutral wastewater medium is then transported to the ground heat transfer medium circulation pipe (2) through the heat exchange pipe (5).

5. The method for heat preservation of cold-region filling pipelines based on carbon dioxide mineralization exothermic reaction according to claim 1, characterized in that, The heat exchange tube (5) has a capillary network structure.

6. The method for heat preservation of cold-region filling pipelines based on carbon dioxide mineralization exothermic reaction according to claim 1, characterized in that, In step S40, the filling pipeline (10) further includes: A temperature sensor (4) is installed inside the slurry conveying pipe (1) and is configured to monitor the temperature of the filling slurry (11) inside the slurry conveying pipe (1).

7. A thermal insulation system for cold-region filling pipelines based on the exothermic reaction of carbon dioxide mineralization, characterized in that, The filling pipeline (10) includes: a slurry conveying pipe (1) and a heat-conducting medium circulation pipe (2) arranged sequentially from the inside to the outside, wherein a heat exchange pipe (5) connected to the heat-conducting medium circulation pipe (2) is provided in the mineralization reaction zone; the insulation system includes: The mathematical model module is configured to conduct CO2 mineralization kinetic experiments on multi-source mine solid waste backfill materials, measure the heat release of the mineralization reaction under different parameters, and establish mathematical models of different parameters and the heat release of mineralization. The established mathematical models of different parameters and the heat release of mineralization are as follows: In the formula, λ represents the comprehensive reactivity coefficient, which covers the following implicit parameters: the influence of local temperature T of the filling body; the synergistic effect of solid waste component vector S=(S1,S2,...,Sn); the correction effect of environmental pressure; microenvironmental parameters; [CO2] is the CO2 volume concentration, and β is the concentration sensitivity index; It is a time decay function; The pipeline laying module is configured to construct a CO2 diffusion law function model for the filled stope, calculate the spatiotemporal variation law of mineralization heat inside the filled stope through function calculation, and lay heat exchange pipes reasonably based on the degree of heat enrichment (5); wherein, the pipeline laying module includes: The diffusion model building unit is configured to couple the CO2 diffusion-reaction equation with the heat conduction equation to extrapolate the spatiotemporal distribution of mineralization heat within the backfilled mined area in real time, establishing a CO2 diffusion model in the porous backfill body. Its expression is as follows: In the formula, C is the molar concentration of CO2 in the filling material, t is the reaction time, and D is the molar concentration of CO2 in the filling material. eff The effective diffusion coefficient of CO2 in the filling material, The Laplace operator for CO2 concentration, R min Here, T represents the mineralization reaction rate, and T represents the local temperature of the filling material. a heat release power derivation unit configured to derive a heat release power q per unit volume directly from a reaction enthalpy change ΔH based on reaction kinetics v whose expression is: In the formula, q v ΔH represents the heat release power per unit volume, and ΔH represents the molar enthalpy change of the mineralization reaction; negative values ​​indicate exothermic reactions. The heat source term embedding unit is configured to embed q v As the heat source term is embedded in the non-steady heat conduction equation, we get wherein is the packing density, c p is the specific heat capacity of the packing, T is the local temperature of the packing, t is time, λ eff is the effective thermal conductivity of the packing, is the Laplace operator of the temperature field; The temperature and heat release intensity unit is configured to solve the equation using the finite volume method, dynamically outputting the temperature T(x,y,z,t) and heat release intensity q within the three-dimensional space of the mining area. v Evolutionary data of (x,y,z,t); The heat acquisition and heating module is configured to capture CO2 mineralization reaction heat in the filling stope by means of heat exchange pipe (5) pre-embedded in the mineralization heat enrichment area of ​​the stope, and heat the ground slurry conveying pipe (1) through heat conduction medium circulation pipe (2). The heat judgment and control module is configured to monitor the temperature change of the slurry in the slurry conveying pipe (1) in real time and determine whether the slurry temperature meets the standard. When the slurry temperature does not meet the standard, the flow rate of the heat-conducting medium (21) in the heat-conducting medium circulation pipe (2) is adjusted according to the temperature data to form a heat preservation closed-loop control.

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