A preparation method of a cold energy trapping system based on MICP technology

Abstract

The application discloses a preparation method of a cold energy trapping system based on a MICP technology, and belongs to the technical field of cold energy storage. Microbial solution is configured, the microbial solution is injected into a target position in a pulse injection mode, and a 5-10 V direct current electric field is applied to the target position during injection; calcium carbonate is generated by microbial catalysis to fill pores and cracks of the target position, and a trapping layer is formed. The application adopts pulse injection to improve the uniformity of microbial distribution, and simultaneously utilizes a low-voltage electric field to guide the injection to improve the migration ability of the microorganisms, so that the microorganisms are uniformly distributed in low-permeability media (such as clay), and the uniformity of the sedimentary layer is improved.

Description

Technical Field

[0001] This invention belongs to the field of cold storage technology, specifically relating to a method for preparing a cold storage closed system based on MICP technology. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] MICP (Microbially Induced Carbonate Precipitation) is a biomineralization technique that involves certain microorganisms altering the pH of the environment and promoting the precipitation of calcium carbonate (CaCO3) by decomposing urea or metabolizing organic matter. This process can be used to enhance soil stability, seal cracks, improve permeability, and increase material strength. The inventors discovered that MICP technology suffers from uneven microbial distribution in low-permeability media (such as clay) during the microbial injection process, leading to uneven deposition layer uniformity and consequently affecting the sequestration effect of the target material. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a cold-capacity closed system based on MICP technology. The present invention combines pulse injection with a low-voltage electric field to improve the migration ability and distribution uniformity of microorganisms, and also to improve the uniformity of the deposition layer.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] The first aspect of the present invention provides a method for preparing a cold-capacity closed-loop system based on MICP technology, comprising:

[0007] A microbial solution is prepared and injected into the target location using a pulse injection method, while a 5-10 V DC electric field is applied to the target location during the injection process; the microorganisms catalyze the generation of calcium carbonate to fill the pores and cracks at the target location, forming a closed layer.

[0008] In some embodiments of the present invention, the preparation method further includes injecting water above the closed layer to form a water seal layer.

[0009] In some embodiments of the present invention, the thickness of the water seal layer is 10-30 cm.

[0010] In some embodiments of the present invention, the preparation of the microbial solution includes: inoculating urease-producing bacteria into a basic culture medium containing a carbon source, a nitrogen source and nutrients to obtain a microbial solution.

[0011] In some embodiments of the present invention, the pulse injection includes: using a multiphase flow injection pipeline to simultaneously inject bubbles and a microbial solution into the target location.

[0012] In some embodiments of the present invention, a microfluidic system is used to control the injection rate of the microbial solution during the injection process.

[0013] In some embodiments of the present invention, the pulse is a variable speed pulse.

[0014] In some embodiments of the present invention, the microbial solution is injected intermittently into the target location.

[0015] In some embodiments of the present invention, a pretreatment solution is injected into the target location before the microbial solution is injected;

[0016] The pretreatment solution is a solution containing 0.01 M glucose and 0.05 M calcium chloride.

[0017] In some embodiments of the present invention, after the closed layer is formed, a post-treatment solution is injected into the target location every 3-5 days.

[0018] The post-treatment solution is a solution containing 0.2 M calcium chloride and 0.5 M urea.

[0019] The beneficial effects of this invention are as follows:

[0020] This invention employs pulsed injection to improve the uniformity of microbial distribution. Simultaneously, a low-voltage electric field is used to guide the injection, enhancing the migration ability of microorganisms and achieving uniform distribution of microorganisms in a low-permeability medium, thereby improving the uniformity of the deposition layer.

[0021] This invention preferably employs a multiphase flow pulse injection method, simultaneously injecting gas and microbial solution into the target location, utilizing bubbles to drive the uniform distribution of microorganisms. Furthermore, the use of variable-speed pulse flow reduces localized accumulation of microorganisms, further optimizing the uniformity of the deposition layer.

[0022] In the preparation process, the present invention uses a microfluidic system to dynamically adjust the injection flow rate of the microbial solution, prevent the microorganisms from being lost with the fluid, and optimize the calcium carbonate deposition rate. Detailed Implementation

[0023] In view of the problems of uneven microbial distribution and uneven deposition layer thickness in existing MIP technology, this invention proposes a method for preparing a cold-capacity trap system based on MIP technology.

[0024] A first typical embodiment of the present invention provides a method for preparing a cold-capacity closed-loop system based on MICP technology, comprising:

[0025] A microbial solution is prepared and injected into the target location using a pulse injection method, while a 5-10 V DC electric field is applied to the target location during the injection process; the microorganisms catalyze the generation of calcium carbonate to fill the pores and cracks at the target location, forming a closed layer.

[0026] This invention improves the uniformity of microorganisms at the target location and enhances their migration ability in low-permeability media by using pulse injection combined with low-voltage electric field guidance.

[0027] Understandably, the target location refers to soil at a certain depth. By injecting a microbial solution into the soil at this depth, microorganisms induce calcium carbonate deposition, improving the sealing properties of the soil at that depth and thus creating a trap layer. Substances such as oil, gas, or cryogenic media exist beneath the trap layer, resulting in a good sealing effect and preventing leakage.

[0028] In some embodiments of this implementation, the preparation method further includes injecting water over the closed layer to form a water seal layer.

[0029] Water has a high specific heat capacity and thermal stability, which helps to isolate the effects of external temperatures and prevent the leakage of cold energy within the closed loop. The water seal provides an effective thermal insulation layer at the top of the cold storage area, reducing the loss of cold energy due to external temperature fluctuations.

[0030] In some embodiments of this implementation, the water seal layer has a thickness of 10-30 cm. This thickness of water seal layer can effectively insulate against external temperatures and prevent heat loss.

[0031] In some embodiments of this implementation, the preparation of the microbial solution includes:

[0032] Urease-producing bacteria are inoculated into a basic culture medium containing carbon source, nitrogen source and nutrients to obtain a microbial solution.

[0033] In this invention, the type of urease-producing bacteria is not required; commonly used urease-producing bacteria in the art can be used, such as Bacillus cereus (…). Pasteur's spore load The carbon source includes, but is not limited to, any one or more of glucose and sodium acetate; the nitrogen source includes, but is not limited to, urea; and the nutrients include, but are not limited to, phosphates. After inoculating the microorganisms into the solution, the pH and temperature conditions are controlled to allow them to grow to the logarithmic or stationary phase, forming an active microbial solution, which is then injected into the soil for mineralization induction. Furthermore, to meet different engineering needs, the microbial solution can also be a conventional liquid fermentation product or a liquid bacterial solution after preliminary concentration treatment; the solution has a non-encapsulated structure.

[0034] In some embodiments of this implementation, the so-called microbial solution comprises: glucose 4-6 g / L, urea 15-25 g / L, peptone 4-6 g / L, potassium dihydrogen phosphate 1-2 g / L, disodium hydrogen phosphate 3-5 g / L, magnesium sulfate 0.1-0.5 g / L, and sodium chloride 4-6 g / L; the concentration of microorganisms in the microbial solution is 10. 8 ~10 10 CFU / mL.

[0035] In some embodiments of this implementation, the pulse injection includes: using a multiphase flow injection pipeline to simultaneously inject bubbles and a microbial solution into the target location.

[0036] Multiphase flow injection pipelines enable multiphase flow transport of bubbles and microbial solutions, improving the uniformity of microbial diffusion. Due to the input of bubbles and the use of bubble-driven technology, a uniform distribution of microorganisms can be ensured.

[0037] In some embodiments of this implementation, a microfluidic system is used to control the injection rate of the microbial solution during the injection process. The microfluidic system can dynamically adjust the injection flow rate to prevent microbial loss and optimize the calcium carbonate deposition rate.

[0038] Understandably, the microfluidic system can be an intelligent microfluidic system that can be combined with a temperature sensor to initiate release at the target temperature, thereby optimizing the MICP process.

[0039] In some embodiments of this implementation, the pulse is a variable-speed pulse. The microfluidic system can be combined with variable-speed injection technology to use low flow rates (5-10 cm / h) in high-permeability media and ultra-low flow rates (<2 cm / h) in low-permeability media.

[0040] In some embodiments of this implementation, the microbial solution is injected intermittently into the target location. A pulse-controlled valve can be used to control the injection of the microbial solution, adjusting the release rate to prevent blockage caused by excessively rapid release at once. Specifically, a solenoid valve combined with a timer can be used to intermittently release the microorganisms, ensuring stable deposition. A pH sensor can also be used to trigger release at the target pH, improving deposition accuracy.

[0041] In some embodiments of this implementation, a pretreatment solution is injected into the target location before the microbial solution is injected;

[0042] The pretreatment solution is a solution containing 0.01 M glucose and 0.05 M calcium chloride.

[0043] Understandably, injecting a pretreatment solution into the target location can reduce the pore fluid shear force, increase the pore water content, and prevent microorganisms from being lost with the fluid due to the large pore size at the target location, thus avoiding a waste of resources.

[0044] In some embodiments of this implementation, after the trap layer is formed, a post-treatment solution is injected into the target location every 3-5 days;

[0045] The post-treatment solution is a solution containing 0.2 M calcium chloride and 0.5 M urea.

[0046] Understandably, by adding post-treatment solution later, microorganisms can be continuously induced to deposit calcium carbonate, thereby increasing the thickness of the deposit layer.

[0047] In some embodiments of this implementation, applying a 5-10 V DC electric field includes the following steps:

[0048] First, an electrode system is set up in the area to be improved. Positive and negative electrodes are arranged in an insert manner at both ends of the injection path or at the upstream and downstream positions of the target area. Preferably, they are arranged within 10-30 cm from the injection point and the improvement boundary. An electric field pair is formed between the anode and the cathode.

[0049] Secondly, the positive and negative electrodes are connected to an external adjustable DC regulated power supply via wires, with the applied voltage range being 5-10 V.

[0050] Furthermore, to achieve dynamic control and high adaptability, the electric field system and the microbial injection system are integrated into the same microfluidic module. Sensors monitor soil conductivity, pore water velocity, and seepage resistance in real time, automatically adjusting voltage and injection rate based on feedback signals. Multiple electrodes can be set up as needed, and the electric field can be applied sequentially or in sections to form a staged electric field propulsion mechanism, thereby achieving precise migration control of microorganisms in deeper or more complex structures. During the application of the electric field, microorganisms, due to their negatively charged surfaces (derived from carboxyl and hydroxyl groups on the cell membrane), undergo electrophoresis under the influence of the electric field, migrating towards the anode. Combined with the original seepage driving force within the soil and local permeability changes, the electric field further improves the spatial uniformity of microbial distribution, helping to form a dense, continuous calcium carbonate deposition structure within the target area, improving the efficiency and spatial consistency of the MIP reaction, and is particularly suitable for directional improvement in medium- to low-permeability sandy soils, silt, or some cohesive soil environments.

[0051] In some embodiments of this implementation, the electrode may be an inert conductive material such as a graphite rod, a carbon electrode rod, or a stainless steel round rod, which has good electrochemical stability.

[0052] In some embodiments of this implementation, to improve the accuracy of electric field application, the anode and cathode are arranged in a ring or multiple sets of staggered arrangements to form a composite electric field pattern.

[0053] In some embodiments of this implementation, to achieve a controllable electric field strength (e.g., 0.25–1.0 V / cm), the electrode spacing is adjusted according to the actual application scenario, ranging from 10 to 40 cm. The electric field strength control is based on the required electrophoretic driving force, which effectively promotes the directional migration of microorganisms while avoiding damage to microbial cell membranes or abnormal ion migration in solution caused by excessively strong electric fields.

[0054] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0055] The raw materials used in the following examples are all commercially available products that can be purchased.

[0056] The microbial solution used in the following examples includes: glucose 5 g / L, urea 20 g / L, peptone 5 g / L, potassium dihydrogen phosphate 1.5 g / L, disodium hydrogen phosphate 4 g / L, magnesium sulfate 0.3 g / L, and sodium chloride 5 g / L; the microorganisms in the microbial solution are Bacillus cereus (Bacillus cereus). Pasteur's spore load The concentration of )) is 10 9 ~10 10 CFU / mL.

[0057] Example 1

[0058] A method for preparing a cold-capacity closed-loop system based on MICP technology includes:

[0059] A three-stage injection method is used:

[0060] (1) Inject a solution containing 0.01 M glucose and 0.05 M calcium chloride into the soil at the target depth.

[0061] (2) Microbial solution injection at a flow rate of 1-3 cm / h. During the injection process, the flow rate is dynamically adjusted using a microfluidic system. A 5-10V DC electric field is used during the injection process.

[0062] First, an electrode system is set up in the area to be improved, with both positive and negative electrodes being graphite rods. The positive and negative electrodes are arranged in an inserted manner at both ends of the injection path, within a range of 20 cm from the injection point and the improvement boundary, forming an electric field pair between the anode and the cathode.

[0063] Secondly, the electrodes are connected to an external adjustable DC regulated power supply via wires, with an applied voltage range of 5–10 V. The electrode spacing is 30 cm.

[0064] The electric field effectively drives negatively charged microorganisms to migrate towards the target modification area, enhancing their enrichment capacity in deep or low-permeability regions. This facilitates the uniform deposition of CaCO3 in the pore space, forming a continuous calcium carbonate cement layer. The electric field application process is synchronized with solution injection, significantly improving the efficiency of the MIP reaction and the structural consistency of the modification zone, avoiding the problems of microbial retention or insufficient local deposition in high-impedance paths.

[0065] In low-permeability media, the injection rate is ≤5 cm / h, and in high-permeability media, the injection rate is ≤10 cm / h. Specific injection methods and depths are shown in Tables 1 and 2.

[0066] Table 1 Injection methods for different underlying types

[0067]

[0068] Table 2 Injection Depth

[0069]

[0070] (3) After injection, supplement with 0.2M calcium chloride and 0.5M urea solution every 3-5 days to continuously induce deposition.

[0071] An injection system can be used during the injection process, as shown in Table 3.

[0072] Table 3 Injection System

[0073]

[0074] The method provided in this embodiment utilizes multiphase flow pulse injection to improve the uniformity of microbial distribution. Furthermore, the injection process is guided by a low-voltage electric field to enhance the migration ability of microorganisms in low-permeability media, thus expanding the application scope of MICP technology from medium- and high-permeability soils to low-permeability soils.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a cold-capacity closed-loop system based on MICP technology, characterized in that, include: Prepare a microbial solution and inject it into the target location using a pulse injection method, while applying a 5-10 V DC electric field to the target location during the injection process; Microorganisms catalyze the production of calcium carbonate to fill the pores and cracks at the target location, forming a closed layer; The pulse injection includes: simultaneously injecting air bubbles and microbial solution into the target location using a multiphase flow injection pipeline; During the injection process, a microfluidic system is used to control the injection rate of the microbial solution.

2. The preparation method according to claim 1, characterized in that, The preparation method further includes injecting water above the closed layer to form a water seal layer.

3. The preparation method according to claim 2, characterized in that, The thickness of the water seal layer is 10-30 cm.

4. The preparation method according to claim 1, characterized in that, The preparation of the microbial solution includes: inoculating urease-producing bacteria into a basic culture medium containing carbon source, nitrogen source and nutrients to obtain the microbial solution.

5. The preparation method according to claim 1, characterized in that, The pulse is a variable speed pulse.

6. The preparation method according to claim 1, characterized in that, The microbial solution is intermittently injected into the target location.

7. The preparation method according to claim 1, characterized in that, Before injecting the microbial solution, inject a pretreatment solution into the target location; The pretreatment solution is a solution containing 0.01 M glucose and 0.05 M calcium chloride.

8. The preparation method according to claim 1, characterized in that, After the trap layer is formed, the post-treatment solution is injected into the target location every 3-5 days; The post-treatment solution is a solution containing 0.2 M calcium chloride and 0.5 M urea.

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