Method for manufacturing carbon material-containing slurry, and method for improving deep ground

Abstract

To provide a novel method for manufacturing a carbon material-containing slurry that can be supplied in situ while preventing a carbon material from separating.SOLUTION: A method for manufacturing a carbon material-containing slurry comprises the steps of: impregnating a carbon material with water; and obtaining a carbon material-containing slurry that contains the water-impregnated carbon material and a hardening agent.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing a slurry containing carbonaceous material and a method for improving deep ground.

Background Art

[0002] Patent Document 1 describes a ground material that contains soft soil and granular material and exhibits strain hardening behavior under the action of shear force under consolidated undrained conditions, and a ground improvement method using the ground material.

[0003] Patent Documents 2 and 3 describe a road construction method in which a reinforcing mesh is laid on a plurality of columns, and a shallow improved soil layer is laid by adding and mixing either one or both of an additive or an additive to earth and sand and a solidifying material on the reinforcing mesh, and road paving is constructed on the shallow improved soil layer, and it is described that rice husks or foam beads are used as the additive or the additive.

[0004] Patent Document 4 describes a lightweight cement-based solidifying material in which a cement-based solidifying material and a dehulling waste such as rice husks are mixed, and Patent Document 5 describes that a dehulling waste such as rice husks is mixed into a ground improvement material obtained by mixing a cement-based solidifying material with in-situ earth and sand.

[0005] Patent Document 6 describes a ground improvement method in which a soil neutralizing agent obtained by mixing 10 to 100% by weight of an acidic solidification aid with 100 parts by weight of magnesium oxide and a water absorbent are used in combination to obtain improved soil, and the improved soil is injected into the soil to be treated in a poor ground or a soft ground, and it is described that activated carbon is used as the water absorbent.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0007] Efforts are underway towards a decarbonized society aiming for zero carbon dioxide emissions, and the construction industry is also required to reduce its carbon dioxide emissions. Carbon neutrality is one of the efforts towards decarbonization against global warming. Carbon neutrality is an effort to aim for "substantially zero" carbon dioxide emissions by offsetting the amount of carbon dioxide emissions and absorption.

[0008] Therefore, also in the production of hardening material slurries and ground improvement methods, in order to bring the carbon dioxide emissions closer to "substantially zero", it is required to incorporate a process that can increase the amount of carbon dioxide absorption by using a material that absorbs carbon dioxide and immobilizing it.

[0009] However, the above Patent Documents 1 to 5 do not disclose anything about the production of slurries containing carbonaceous materials and deep ground improvement methods.

[0010] Also, the above Patent Document 6 does not disclose anything about the problems when supplying a slurry containing a carbonaceous material to a deep ground.

[0011] When producing a slurry containing a carbonaceous material, when mixing with a hardening material slurry to supply the carbonaceous material to a deep ground, a problem occurs in that the carbonaceous material and the hardening material slurry separate.

[0012] One aspect of the present invention has been made in view of the above problems, and an object thereof is to realize a new method for manufacturing a carbon material-containing slurry that can be supplied in-situ while preventing the separation of carbon materials, and related technologies.

Means for Solving the Problems

[0013] In order to solve the above problems, a method for manufacturing a carbon material-containing slurry according to one aspect of the present invention includes a step of impregnating a carbon material with water, and a step of obtaining a carbon material-containing slurry including the carbon material impregnated with the water and a curing material.

Effects of the Invention

[0014] According to one aspect of the present invention, there is an effect that a new method for manufacturing a carbon material-containing slurry that can be supplied in-situ while preventing the separation of carbon materials, and related technologies can be realized.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0016] <Method for Manufacturing Carbon Material-Containing Slurry and Deep Ground Improvement Method> The method for manufacturing a carbon material-containing slurry according to one aspect of the present invention includes a step of impregnating a carbon material with water, and a step of obtaining a carbon material-containing slurry including the carbon material impregnated with the water and a curing agent. Further, the method for improving deep ground according to one aspect of the present invention includes a step of pumping the carbon material-containing slurry into the deep ground with a pump, and a step of improving the deep ground by mixing the carbon material-containing slurry into the deep ground. The method for manufacturing a carbon material-containing slurry according to one aspect preferably includes a step of pulverizing the carbon material before the step of impregnating the carbon material with water.

[0017] The carbon material-containing slurry is a slurry containing a carbon material, a curing agent, and water, and can improve the deep ground obtained by mixing it into the deep ground. An improved material generated by mixing the carbon material-containing slurry into the deep ground hardens to form an improved body in the deep ground. A method for improving deep ground that forms an improved body in the deep ground using the carbon material-containing slurry manufactured by the manufacturing method according to one aspect and thereby improves the deep ground is also within the scope of the present invention.

[0018] FIG. 1 is a schematic diagram for explaining a deep ground improvement system 100 for performing a method for manufacturing a carbon material-containing slurry and a method for improving deep ground according to one aspect of the present invention. FIG. 2 is a diagram for explaining an outline of a tank 12 provided in the deep ground improvement system 100 shown in FIG. 1.

[0019] The deep ground improvement system 100 shown in FIG. 1 is a system for performing a deep mixing method (CDM method), and includes a slurry plant 10 for manufacturing a carbon material-containing slurry and a mixing processor 20.

[0020] The slurry plant 10 is provided with a measurement unit 11, a tank 12, a mixer 13, and a flowmeter 15, and preferably includes an agitator 14 and a pump P. The pump P pumps the carbon material-containing slurry to the mixing processor 20. The mixing processor 20 is provided with a pump (not shown in FIG. 1) that pumps the carbon material-containing slurry into the ground (deep ground) G, and rods (transport pipes) 21 and 22 for supplying the carbon material-containing slurry to the ground G.

[0021] The measurement unit 11 measures the flow rates of the carbon material, water, a hardening material described later, and an admixture added as necessary, and the carbon material-containing slurry pumped from the agitator 14. Further, the measurement unit 11 can control the flow rate of the carbon material-containing slurry to the target location based on the data of the flow rate of the carbon material-containing slurry measured by the flowmeter 15.

[0022] (Step of pulverizing the carbon material) In the method for manufacturing a deep ground improvement material according to one aspect, it is preferable to use the powder of the pre-pulverized carbon material by a step of pulverizing the carbon material before the step of impregnating the carbon material with water. Thereby, the dispersion stability of the carbon material in the carbon material-containing slurry can be enhanced, and it is possible to prevent the carbon material from floating and separating on the surface of the carbon material-containing slurry.

[0023] In the step of pulverizing the carbon material, the carbon material may be pulverized by a pulverizer (not shown). Examples of the pulverizer include known pulverizing devices such as a roller mill and a high-speed mill.

[0024] From the viewpoint of carbon neutrality, the carbon material is preferably so-called biochar derived from plants that have grown by absorbing carbon dioxide. Examples of biochar include bamboo charcoal, charcoal, and rice husk charcoal. Among biochars, bamboo is preferable because it grows fast and has a fast felling & tree-planting cycle, and thus efficient carbon dioxide absorption is achieved. Note that the water impregnated into the carbon material may be any of fresh water, brackish water, and seawater.

[0025] The carbon material has a porous structure and a bulk density of 0.4 g / cm 3 The bulk density is as small as about 1 / 1000 of the particle size. Although the carbonaceous material may be obtained by passing through a sieve with a certain mesh size as described later, the bamboo charcoal mentioned above is generally commercially available in chunks or sticks with a size of several centimeters. When a carbonaceous material with such a low bulk density and large particle size is simply mixed into a slurry containing a hardener, the carbonaceous material floats on the hardener slurry, and the carbonaceous material and the hardener slurry are separated. Regarding the separation of the carbonaceous material in water, the terminal velocity of the settling of the carbonaceous material can be calculated by the Stokes equation shown below.

[0026]

number

[0027] In the above formula, ν is the terminal velocity in particle settling, D is the particle diameter, ρ p is the particle density, ρ f represents the density of the fluid, g represents the gravitational acceleration, and η represents the viscosity of the fluid.

[0028] The bulk density of the carbon material is 0.4 g / cm as mentioned above. 3 If the carbon material is dissolved in seawater (density 1.03 g / cm 3 When seawater is impregnated into the carbon material (approximately 0.001 Pa s viscosity), the density of the carbon material impregnated with seawater is 1.05 g / cm 3 In contrast, the hardening material, cement, has a particle size of about 10 μm and a density of 3.15 g / cm 3 Using the above Stokes equation, the terminal velocity ν of cement in seawater is estimated to be about 1.16 cm / s. The terminal velocity ν of cement particles in seawater and the density ρ of seawater, which is a fluid, f and viscosity η, and density ρ of carbon material impregnated with seawater p 1.05g / cm 3 From this, the particle size of the carbonaceous material having a terminal velocity approximately equal to the terminal velocity ν of the cement particle is evaluated to be 1.03 mm. In addition, the density of the carbonaceous material precipitated in fresh water (density 1.0) instead of seawater is 1.02 g / cm3 When it reaches a certain level, it is estimated that the particle size of the carbon material having a terminal velocity equivalent to the terminal velocity of the cement particles is evaluated to be 1.04 mm. The density of the carbon material impregnated with water, as evaluated from the terminal velocity, is 1.02 g / cm 3 ~1.30 g / cm 3 from the viewpoint of preventing separation from the cement particles, which is more preferable, and 1.05 g / cm 3 ~1.30 g / cm 3 is more preferably the case.

[0029] From the viewpoint of preventing separation due to the floating of the carbon material in water, it is preferable to previously pulverize the carbon material so that it passes through a sieve having an opening of 5 mm. By pulverizing so as to pass through a sieve with an opening of 5 mm, there is also an advantage that when discharging the slurry from the first discharge ports 212 and 222 and the second discharge port 231 of the mixing processor 20 described later, the carbon material can be prevented from clogging these discharge ports. Furthermore, it is more preferable to pulverize the carbon material so that it passes through a sieve having an opening of 2 mm. As the sieve for evaluating the particle size of the pulverized carbon material, a sieve conforming to JIS Z8801-1 may be used in either case where the particle size of the carbon material is 5 mm or less or 2 mm or less. For example, the carbon material passing through a sieve having an opening of 2 mm may have an average particle size (D50) of about 1 mm.

[0030] The measuring unit 11 measures the carbon material so that the weight of the carbon material as the dry weight is 150 kg or more and 300 kg or less per 1 m 3 of the total of the hardening material and the water contained in the slurry of the hardening material. By making the amount of the carbon material 150 kg or more, a carbon material-containing slurry capable of being fixed using a material that absorbs carbon dioxide can be obtained, and the deep ground can be improved with the carbon material-containing slurry.

[0031] 〔Step of impregnating the carbon material with water〕 In the step of impregnating the carbon material with water, the carbon material is impregnated with water. Thereby, water can be included in the porous structure of the carbon material, and the density of the particles constituting the powder of the carbon material can be made close to the density of water.

[0032] In the step of impregnating the carbon material with water, the carbon material and water measured by the measuring unit 11 may be put into the tank 12, and pressure may be applied to the put carbon material and water. The tank 12 provided with the pressurizing unit 121 shown in FIG. 2 can quickly impregnate a large amount of carbon material with water. The tank 12 can be realized, for example, by a pressure device including a water storage tank and a plate-shaped weight that covers the water surface of the water stored in the water storage tank as a pressurizing unit. Further, the step of impregnating the carbon material with water may be realized by immersing the carbon material in a bag material with a weight in deep water (pond or sea) to apply water pressure.

[0033] The pressure applied to the water into which the carbon material is put by the pressurizing unit 121 provided in the tank 12 may be 100 kPa or more as a high pressure for quickly permeating water into the voids of the porous structure of the carbon material. Thereby, the carbon material having a porous structure can be quickly impregnated with water.

[0034] The tank 12 may be provided with a drainage part (not shown). From this, excess water may be drained from the drainage part, the sediment of the carbon material whose density has been adjusted by impregnating with water may be recovered, and it may be supplied to the mixer 13. Further, the tank 12 may supply the carbon material impregnated with water to the mixer 13 from the tank 12 as dispersed water of the carbon material without draining excess water.

[0035] 〔Step of obtaining carbon material-containing slurry〕 In the step of obtaining the carbon material-containing slurry, a curing material is mixed with the water-containing carbon material to produce a carbon material-containing slurry. The mixing of the water-impregnated carbon material and the curing material may be performed by the mixer 13. The curing material, water and / or admixture may be put into the mixer 13 by the measuring unit 11.

[0036] The hardening material to be mixed with the carbon material is typically cement, which may be Portland cement, blast furnace cement containing blast furnace slag, fly ash cement, etc. Further, the hardening material may be a neutral hardening material containing magnesium oxide and an acidic hardening aid such as aluminum sulfate.

[0037] The carbon material-containing slurry may contain admixtures such as thickeners, high-performance water reducers, high-performance AE water reducers, and fluidizing agents, and thereby the viscosity of the hardening material slurry may be adjusted. Further, the carbon material-containing material slurry may contain bubbles formed by a foaming agent.

[0038] In the step of obtaining the carbon material-containing slurry, assuming the total weight of water and the hardening material is 100%, it is preferable to adjust the weight of water mixed into the hardening material slurry to 50% or more and 100% or less, and more preferably 80% to 100% or less. Thereby, appropriate viscosity can be imparted to the carbon material-containing slurry, and the fluidity of the hardening material slurry in the rods (transport pipes) 20 and 21 provided in the mixing processor 20 can be ensured. Further, separation of the carbon material when the hardening material slurry and the carbon material are mixed can be prevented. Note that the water used for manufacturing the hardening material slurry is not limited and may be fresh water, brackish water, or seawater.

[0039] In the step of obtaining the carbon material-containing slurry, it is preferable to determine the amount of water to be mixed into the hardening material by subtracting the amount of water contained in the sediment of the carbon material obtained in the tank 12 or the dispersed water of the carbon material.

[0040] The carbon material-containing slurry can be transferred from the mixer 13 to the agitator 14.

[0041] [Step of pumping the carbon material-containing slurry into the deep ground with a pump] In the step of pumping the carbon material-containing slurry into the deep ground with a pump, as shown in Fig. 1, the carbon material-containing slurry may be supplied to the ground (deep ground) G by the mixing processor 20, and the carbon material-containing slurry and the soil contained in the ground G may be mixed. By mixing the carbon material-containing slurry with the soil contained in the ground G, deep ground improvement for improving the ground G is carried out. Note that mixing the carbon material-containing slurry with the soil contained in the ground G can also be simply said to be mixing the carbon material-containing slurry into the ground G.

[0042] The mixing processor 20 shown in Fig. 1 includes a pair of two-stage rods 21 and 22 configured such that the carbon material-containing slurry passes through the inside, and the rods 21 and 22 are synchronously rotationally driven by a motor (not shown) or the like, and the rods 21 and 22 are configured to move up and down (penetrate and withdraw) with respect to the ground G. In the mixing processor 20, the agitator 14 can pump the carbon material-containing slurry while stirring the carbon material-containing slurry by the pump P.

[0043] The pair of rods 21 and 22 includes stirring blades 211 and 221 composed of a plurality of stirring blades provided so as to protrude along the direction orthogonal to the rod axis, and first discharge ports 212 and 222 provided in the vicinity of the rod tips and opening in directions opposite to each other by 180 degrees in the circumferential direction. Further, the pair of rods 21 and 22 includes a second discharge port 231 provided substantially at the center between the rods 21 and 22 below the fixed discharge pipe 23, and the stirring blades 211 and 221 are fixed to the rods 21 and 22 so as to be rotatable.

[0044] When the mixing processor 20 synchronously rotationally drives the rods 21 and 22, the stirring blades 211 and 221 do not contact each other, and the vicinity and directly above the first discharge ports 212 and 222, and directly below the second discharge port 231 are stirred.

[0045] The mixing processor 20 can control the forward rotation (penetration) and reverse rotation (extraction) of the rods 21 and 22, and can change the penetration speed, extraction speed, and rotation speed. Further, the mixing processor 20 can control the switching between discharging and non-discharging of the carbon material-containing slurry from the first discharge ports 212 and 222, and the switching between discharging and non-discharging of the carbon material-containing slurry from the second discharge port 231.

[0046] For deep ground improvement, it is advisable to confirm the construction position by means of GNSS, optical wave meters, etc., confirm the water depth at the water bottom surface, confirm that the depth and inclinometer of the rods 21 and 22 are zero, and manage and control the penetration speed, rotation speed of the rods 21 and 22, and the extraction speed and rotation speed.

[0047] By mixing the carbon material-containing slurry by the mixing processor 20 into the soil containing the ground G, the deep ground improvement material, which is the carbon material-containing slurry mixed with the soil, hardens, and a columnar improved pile (improved body) 50 having an improved top end on the water bottom surface as shown in FIG. 1 can be constructed from the designed improvement depth. Therefore, a deep ground improvement method for improving deep ground using the carbon material-containing slurry according to one aspect is also within the scope of the present invention.

[0048] Above, the manufacturing method of the carbon material-containing slurry and the deep ground improvement method have been described by exemplifying the deep mixing treatment method (CDM method) using the deep ground improvement system 100 shown in FIG. 1. However, the manufacturing method of the carbon material-containing slurry and the deep ground improvement method can supply the carbon material-containing slurry to the deep ground by means of a rod (transport pipe) while preventing the separation of the carbon material. That is, it can be applied to all general deep ground improvement methods of supplying the carbon material-containing slurry to the deep ground by means of a rod (transport pipe), and examples of such deep ground improvement methods include the high-pressure jet mixing method.

[0049] 〔Summary〕 The manufacturing method of the carbon material-containing slurry according to Aspect 1 of the present invention includes a step of impregnating the carbon material with water, and a step of obtaining a carbon material-containing slurry containing the carbon material impregnated with the water and a hardening material.

[0050] According to the above aspect, by impregnating the finely crushed carbon material with water, the density of the carbon material can be made greater than that of water, whereby a carbon material-containing slurry can be produced that can be supplied in situ while preventing the carbon material from separating from the hardening material slurry.

[0051] Further, in the method for producing a carbon material-containing slurry according to Embodiment 2 of the present invention, in the above Embodiment 1, before the step of impregnating the carbon material with water, the carbon material may be pulverized, and the water may be impregnated into the powder of the carbon material that has passed through a sieve with an opening of 5 mm.

[0052] According to the above aspect, while preventing the carbon material from separating from the hardening material slurry, it is possible to prevent the discharge port of the hardening material slurry provided in the transport pipe (rod) for supplying the carbon material contained in the hardening material slurry to the deep ground from being blocked by the carbon material.

[0053] Further, in the method for producing a carbon material-containing slurry according to Embodiment 3 of the present invention, in the above Embodiment 1 or 2, before the step of impregnating the carbon material with water, the carbon material may be pulverized, and the water may be impregnated into the powder of the carbon material that has passed through a sieve with an opening of 2 mm.

[0054] According to the above aspect, it is possible to further prevent the carbon material from separating from the hardening material slurry.

[0055] Further, in the method for producing a carbon material-containing slurry according to Embodiment 4 of the present invention, in any one of the above Embodiments 1 to 3, the step of impregnating the carbon material with water is preferably performed under pressure conditions.

[0056] According to the above aspect, a large amount of carbon material can be quickly impregnated with water.

[0057] Further, in the method for producing a carbon material-containing slurry according to Embodiment 5 of the present invention, in any one of the above Embodiments 1 to 4, the density of the carbon material impregnated with the water is preferably 3 ~1.30 g / cm 3 .

[0058] According to the above configuration, it is possible to further prevent the separation of the carbon material from the hardening material slurry.

[0059] Moreover, in the method for producing a carbon material-containing slurry according to aspect 6 of the present invention, in any of the above aspects 1 to 5, after the step of impregnating the carbon material with water, the sediment of the settled carbon material is recovered from the water, and in the step of obtaining the hardening material slurry, the sediment, the hardening material, and water are mixed to obtain the carbon material-containing slurry.

[0060] According to the above aspect, by impregnating with water, the sediment of the carbon material whose density has been adjusted is recovered, and the hardening material slurry can be produced so that the carbon material does not separate.

[0061] Moreover, in the method for producing a carbon material-containing slurry according to aspect 7 of the present invention, in any of the above aspects 1 to 5, in the step of obtaining the carbon material-containing slurry, the dispersion water of the carbon material impregnated with the water and the hardening material are mixed to obtain the carbon material-containing slurry.

[0062] According to the above aspect, the dispersion water of the carbon material and the hardening material are mixed to produce the hardening material slurry so that the carbon material does not separate.

[0063] Moreover, the deep ground improvement method according to aspect 8 of the present invention includes a step of pumping the carbon material-containing slurry produced by performing the method for producing the carbon material-containing slurry according to any of the above aspects 1 to 7 into the deep ground with a pump, and improving the deep ground by mixing the carbon material-containing slurry into the deep ground.

[0064] According to the above aspect, the improvement of the deep ground can be performed while preventing the separation of the carbon material by the carbon material-containing slurry.

[0065] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope indicated in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Industrial Applicability

[0066] The present invention can be used for improving deep ground, for example, improving deep ground under the seabed.

Explanation of Signs

[0067] 10 Slurry plant 11 Measuring unit 12 Tank 121 Pressurizing section 13 Mixer 14 Agitator 15 Flowmeter 20 Mixing processor 21, 22 Rods 211, 221 Stirring blades 212, 222 First discharge port 231 Second discharge port 50 Improved pile (improved body, deep ground improvement material)

Claims

1. A step of impregnating a carbon material with water, and A step of obtaining a carbon material-containing slurry including the carbon material impregnated with the water and a curing agent, the method for manufacturing a carbon material-containing slurry.

2. Before the step of impregnating the carbon material with water, the carbon material is pulverized, and the carbon material powder that has passed through a sieve with an opening of 5 mm is impregnated with the water. The method for manufacturing a carbon material-containing slurry according to Claim 1.

3. Before the step of impregnating the carbon material with water, the carbon material is pulverized, and the carbon material powder that has passed through a sieve with an opening of 2 mm is impregnated with the water. The method for manufacturing a carbon material-containing slurry according to Claim 1.

4. The step of impregnating the carbon material with water is performed under pressurized conditions. The method for manufacturing a carbon material-containing slurry according to Claim 1.

5. The density of the carbon material impregnated with the water is 1.02 g / cm ３ to 1.30 g / cm ３ The method for producing a slurry containing a carbon material according to claim 1, wherein the density is as described above.

6. After the step of impregnating the carbon material with water, the sediment of the settled carbon material is recovered from the water, and In the step of obtaining the carbon material-containing slurry, the sediment, the curing agent, and water are mixed to obtain the carbon material-containing slurry. The method for manufacturing a carbon material-containing slurry according to Claim 1.

7. In the step of obtaining the carbon material-containing slurry, the dispersion water of the carbon material impregnated with the water and the curing agent are mixed to obtain the carbon material-containing slurry. The method for manufacturing a carbon material-containing slurry according to Claim 1.

8. Including a step of pumping the carbon material-containing slurry manufactured by performing the method for manufacturing a carbon material-containing slurry according to any one of Claims 1 to 7 into deep ground with a pump, and By mixing the carbon material-containing slurry into the deep ground, the deep ground improvement method for improving the deep ground.

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