JP2013185065A - Resistance reducing agent and fluid control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resistance reducing agent which never contaminates a fluid and is excellent in the resistance reducing effect of the fluid with less environmental load, and a fluid control method using the resistance reducing agent.SOLUTION: This resistance reducing agent for reducing the resistance of a fluid flowing through piping is composed of a plant-derived fiber, and has an average fiber length of 0.3-2.5 mm and an average aspect ratio of 70-120. The fluid control method for reducing the resistance of a fluid flowing through piping includes: mixing the resistance reducing agent with the fluid prior to circulation of the fluid through the piping.

Description

  The present invention relates to a resistance reducing agent and a fluid control method for reducing resistance due to turbulent flow of fluid flowing in a pipe.

  In recent years, research on the resistance reduction effect of fluids typified by thermal energy transport systems has attracted attention from the viewpoint of energy saving against global warming, which is a problem. When fluid is circulated in the pipe, a resistance is generated between the fluid and the inner wall of the pipe, and a loss occurs in the flow of the fluid due to this resistance, and this loss requires more power than necessary to operate the pump. There's a problem. Various proposals have been made to solve this problem by adding a resistance reducing agent to the fluid to reduce frictional resistance, greatly reducing the power of the pump, and these proposals can be expected to reduce energy. .

  Since most of the flow in such a system is turbulent, the resistance reduction effect in the turbulent region is particularly important. As additives for reducing the resistance, surfactants, polymers, synthetic fibers, asbestos and the like can be mentioned at present, and various patent documents 1 and 2 have been proposed.

Japanese Patent Laid-Open No. 2002-80820

JP 2004-107521 A

However, since the polymer is mechanically deteriorated, if the polymer is continuously used in the circulation system, the resistance reduction effect is lost and it is not suitable for practical use. On the other hand, surfactants have almost no deterioration due to mechanical shearing and can be used in circulation systems, and have practically superior properties. Therefore, in recent years, it has been used in urban thermal energy supply pipeline systems and building air conditioning and air conditioning systems, but the aqueous surfactant solution cannot be easily recovered during drainage because it dissolves in the liquid liquid. . Therefore, its application is limited to a closed circuit pipeline system.
On the other hand, unlike surfactants and polymers, fibers are considered to be recoverable from the suspension, and can be expected to greatly reduce the cost of drainage.
Up until now, synthetic fibers such as nylon (registered trademark) and rayon (registered trademark), asbestos, etc. have been widely used. However, at present, sufficient effects cannot be obtained with synthetic fibers unless they are added to a considerably high concentration. However, the use of asbestos is restricted due to consideration of the human body and the environment.

  In short, there are currently no resistance reducing agents used in conventional fluid control methods that have both a sufficient resistance reduction effect and a reduction in environmental load. Currently, there is a demand for development.

  Accordingly, an object of the present invention is to provide a resistance reducing agent that does not pollute the fluid, has a low environmental load, and is excellent in the resistance reduction effect of the fluid, and a fluid control method using the resistance reducing agent. .

As a result of intensive studies to solve the above-mentioned problems, the present inventors can exert a fluid resistance reducing action even if the fiber is derived from a plant such as a surfactant that cannot be dissolved or dispersed inseparably from the fluid. This has been found and the present invention has been completed.

That is, the present invention provides the following inventions.
1. A resistance reducing agent for reducing the resistance of a fluid flowing in a pipe, comprising a plant-derived fiber, having an average fiber length of 0.3 to 2.5 mm and an average aspect ratio of 70 to 120. Resistance reducing agent.

2. 2. The resistance reducing agent according to 1, wherein the plant-derived fiber has a Young's modulus of 15 to 28.

3. 2. The resistance reducing agent according to 1, wherein the plant-derived fiber is a bamboo-derived fiber.

4). A fluid control method for reducing the resistance of a fluid flowing in a pipe, wherein the resistance reducing agent according to 1 is mixed before the fluid is circulated in the pipe.

5. 5. The fluid control method according to 4, wherein the concentration of the plant-derived fiber with respect to the fluid is 2000 to 10,000 ppm.

The resistance reducing agent of the present invention does not pollute the fluid, has a low environmental load, and can reduce the resistance of the fluid.
According to the fluid control method of the present invention, the fluid is not contaminated, the environmental load is small, and the resistance of the fluid can be reduced.
This point will be described in more detail. Since the fluid control method of the present invention uses plant-derived fibers as a resistance reducing agent, the plant-derived fibers are not dissolved in the fluid and are not mixed into the fluid, so the environmental load is small. . It can be recovered and reused. Moreover, since there is little energy loss, the energy consumption required for the distribution | circulation of the fluid in piping, such as operation of a pump, can be suppressed.

FIG. 1 is a schematic view showing an outline of an apparatus for carrying out the fluid control method of the present invention. FIG. 2 is a photomicrograph of the bamboo single fiber used in the examples. FIG. 3 is a chart showing the results of experiments conducted in the examples. FIG. 4 is a chart showing the results of experiments conducted in the examples. FIG. 5 is a chart showing the results of experiments conducted in the examples.

DESCRIPTION OF SYMBOLS 1 Piping apparatus 10 Fluid tank 21 Pump 22 Valve 23 Flow meter 24 Acrylic piping 25 Pressure transducer 26 Personal computer

Hereinafter, the present invention will be described in detail with reference to the drawings as appropriate, but the present invention is not limited thereto.
(Resistance reducing agent)
First, the resistance reducing agent of the present invention will be described.
The resistance reducing agent is made of bamboo-derived fibers, the average fiber length is 0.3 to 2.5 mm, preferably 0.5 to 1.5 mm, and the average aspect ratio is 70 to 120, preferably 80 to 100. is there.
When the average fiber length is less than 0.5 mm, separation from the fluid is difficult, and when it exceeds 2 mm, the resistance reduction effect is lowered.
On the other hand, if the aspect ratio is outside the above range, the resistance reduction effect is lowered and separation from the fluid becomes difficult.

In addition, preferable examples of the plant-derived fiber include bamboo, conifers, hardwoods, straw, cotton, Manila hemp reed, kenaf, linter, sugar cane, mulberry, and the like, and bamboo is particularly preferable in the fluid control method of the present invention. Moreover, about plants other than bamboo, what made those pulp into a raw material can be used as a resistance reducing agent of this invention.
That is, the plant-derived fiber (resistance-reducing agent of the present invention) particularly preferably used in the present invention is made of bamboo-derived fibers, has an average fiber length of 0.5 to 2 mm, and an average aspect ratio of 70 to 100. It is a derived fiber.

The Young's modulus of the plant-derived fiber is preferably 15 to 28 GPa from the viewpoint of further enhancing the resistance reduction effect, and more preferably 18 to 25 GPa.
The average fiber diameter is preferably 5 to 30 μm, more preferably 5 to 20 μm.
The shape of the fiber (for each fiber) is not particularly limited, but is preferably linear.

If the said plant-derived fiber is a bamboo single fiber, for example, it can obtain as follows.
Divide the raw material bamboo into appropriate size, remove inner and outer hindrances that hinder fiber separation, and then press with a roll press machine to improve alkali treatment efficiency, and parenchyma tissue Crack.
Next, boil it in a 2 to 3 wt% aqueous sodium hydroxide solution for 2 hours, press it again after washing it with water, further break down the softened parenchyma tissue, wash away the parenchyma tissue with sufficient water washing, and remove the fiber bundle. obtain.
The fiber bundle is agitated with water for 1 to 2 minutes with a mixer, the fiber bundle is separated into bamboo single fibers, and the remaining soft cells are separated and removed by washing with water in a coarse wire mesh. Bamboo monofilament as the origin fiber is obtained.

(Fluid control method)
Next, the fluid control method of the present invention will be described.
The fluid control method of the present invention can be carried out by mixing the plant-derived fiber with the fluid before circulating the fluid through the piping when the fluid is circulated through the piping.
As the fluid to be controlled by the fluid control method of the present invention, a liquid is preferably used. Although it does not restrict | limit especially as a liquid, Water, warm water, various refrigerant | coolants, such as ethylene glycol, sewage (sewage), a fire extinguishing agent, etc. can be mentioned.
The pipe forming material, pipe diameter, and the like are not particularly limited, but examples of the forming material include acrylic resin, polyvinyl chloride, stainless steel, steel, copper, aluminum, and polyethylene. The tube diameter is not particularly limited as long as it is a commonly used inner diameter, but is preferably 5 mm or more, more preferably 7 mm or more, and the upper limit of the inner diameter is the size of the diameter used for ordinary piping. If it is, it will not be restrict | limited in particular. Also, the shape of the pipe can be various forms such as a straight line, an L shape, an S shape, and a U shape. The inner diameter of the pipe can correspond to various shapes such as a circle and a rectangle.
Hereinafter, after showing one Embodiment of the apparatus with which the fluid control method of this invention is applied, the detail of the fluid control method of this invention is demonstrated.

[Piping equipment]
A piping device 1 shown in FIG. 1 includes a tank 10 for storing water as a fluid and a piping 20, and the piping 20 includes a pump 21, a valve 22, and a flow meter 23. Further, an acrylic piping portion 24 for measuring pressure loss is provided downstream of the flow meter 23. And measure how much pressure loss can be made at a certain distance. The measured data is measured with a pressure variometer, and the measured data is sent to the personal computer 26 and stored, and is input to a spreadsheet software to manage the transition in a time series.
The entire pipe 20 is formed of an acrylic resin pipe, and in the present embodiment, the above-described measurement pipe portion 24 is provided. However, the piping portion 24 does not need to be provided in particular, and the piping may be entirely formed of one forming material or may be formed of two or more forming materials. In this embodiment, the acrylic tube portion has a length of 900 mm as a whole, and the interval between the pressure measurement holes is 300 mm and the run-up section is 600 mm so that the pressure loss can be measured. The inner diameter of the pipe 20 is 10 mm.
The piping device to which the present invention is applied is not limited to the example shown in FIG. 1 and can be suitably used for piping devices in various application situations. For example, a refrigerant circulation device of a chemical plant, a hot water / cold water circulation system of a building or city, and the like can be mentioned.

[Amount used (mixed concentration)]
The use amount of the plant-derived fiber is preferably such that the lower limit is set to 2000 ppm and the upper limit is set to 10,000 ppm as the mixed concentration of the plant-derived fiber in order to sufficiently exert the resistance reduction effect. The upper limit of the more preferable concentration is 7000 ppm, and the lower limit of the most preferable concentration is 4000 ppm.
The mixing concentration is a ratio between the weight of the mixed dispersion obtained by dispersing dried plant-derived fibers in a solvent and the weight of the plant-derived fibers.

(Control operation)
A fluid control operation will be described.
First, water as a fluid is introduced into the tank 10 so that the inlet and outlet of the pipe 20 are immersed in the water of the tank 10. Next, the pump 21 is operated to transfer water toward the valve 22 (flow direction indicated by the arrow in the figure). The valve 22 is opened to allow fluid to flow. At this time, the opening degree of the valve 22 is appropriately adjusted while confirming the flow rate with the flow meter 23.
The water flowing through the predetermined flow path (pipe) is discharged from the discharge port of the pipe and returns to the tank 10. At this time, although not shown in particular, plant-derived fibers mixed in water can be removed by installing a net of a predetermined mesh at the outlet of the pipe and allowing the fluid to pass therethrough.
In addition, if the tank is equipped with a thermostatic device, the temperature of the fluid can be kept constant.

〔effect〕
By controlling the fluid as described above, the resistance of the fluid can be reduced, and the output of the pump can be suppressed, so that fluid flow with high energy efficiency can be enabled.
In addition, since the resistance reducing agent of the present invention does not dissolve in the fluid, there is no foreign matter mixed in the fluid. For example, when the fluid is water, there is no environmental load even if it is discarded as it is. In addition, it can be collected and reused, contributing to resource saving. Since there is little energy loss when circulating fluid, energy saving effect is high.

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. Various modifications can be made without departing from the spirit of the present invention.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not restrict | limited at all to these.

[Example 1]
As a plant-derived fiber, a bamboo single fiber obtained in accordance with the above-described manufacturing method is used, and water is circulated using the piping apparatus shown in FIG. The resistance reduction effect of was measured.
FIG. 2 shows a photomicrograph of the used bamboo single fiber dispersed in water, which is a fluid. The average fiber length of this fiber was 1.19 mm, the average diameter was 13.3 μm, and the average aspect ratio was 89.7. Further, it can be confirmed from FIG. 2 that the fibers are linear and both ends are needle-like. In the following, various measurements are performed, and all of these bamboo single fibers are used.
The concentration of the bamboo single fiber was variously changed to each amount shown in FIG. 3, and the relationship between the concentration and the resistance reduction rate DR was measured. The mixing concentration Cw of bamboo single fiber was determined by the ratio of the mass of dried fiber to the mass of tap water [the mass of fiber / (the mass of fiber + the mass of water)]. The result is shown in FIG.
DR was obtained from the following equation.
DR [%] = {(λwater−λsuspension) / λwater} × 100 [%] (1)
λ _water is the tube friction coefficient of water, and λ _suspension is the tube friction coefficient of the test fluid.
As is clear from the results shown in FIG. 3, DR increases as Cw increases, but does not change after Cw = 3500 ppm. A synthetic fiber such as nylon having substantially the same fiber length and fiber diameter has been reported to require about Cw = 10000 ppm to obtain a reduction effect. Therefore, according to the present invention, a concentration lower than that of the prior art is sufficient. It can be seen that a resistance reduction effect is obtained.

Next, the pipe diameter was variously changed to the size shown in FIG. 4, and the relationship between the pipe diameter and the resistance reduction effect was measured. FIG. 4 shows the relationship between DR and Reynolds number Re at Cw = 3500 ppm for each tube diameter d.
It can be seen that DR increases as the tube diameter increases. Further, it can be seen that DR varies depending on Re and shows the maximum DR at around Re = 20000 for any tube diameter. From this result, it can be seen that the resistance reducing agent of the present invention is effective at various pipe diameters.

Next, the concentration Cw = 3500 ppm, and a net with a hole diameter of 0.3 mm is installed at the outlet of the pipe so that fibers can be collected. After installing the net, whether DR is collected or not It was confirmed by measuring whether it changed to. The horizontal axis represents the time t after the installation of the net, and the number N of times that the water in the tank calculated from the flow rate has passed through the net. It can be seen that DR decreases as t and N increase, becomes almost zero at t = 300 s and N = 25, and returns to the pipe friction coefficient of water. From this result, it is understood that the fiber can be completely recovered by passing the net.
Further, the Young's modulus was measured when the bamboo single fiber of this example was mixed in water at a concentration Cw of 0.35 wt% (3500 ppm). The results are shown in Table 1. Moreover, DR in that case is 2-20, and resistance is reducing compared with the case where a resistance reducing agent is not added.
As a comparison, DR, nylon fiber, rayon fiber, and asbestos fiber when no fiber was used were measured for the concentration at which DR reduction was observed, Young's modulus, and DR, respectively. The results are shown in Table 1.
The resistance reduction effect was determined by whether or not there was a reduction in DR at a concentration of 3500 ppm.
As is clear from the results shown in Table 1, nylon fibers and rayon fibers cannot obtain a sufficient effect at a low concentration similar to the bamboo short fibers of this example, and these synthetic fibers have a high environmental load. . Moreover, when the effect was seen with asbestos fibers, the aspect ratio was too high, making it difficult to collect and high environmental impact.

From the above experimental results, the following can be understood.
(1) A fluid in which bamboo single fibers having a predetermined fiber length and aspect ratio were suspended exhibited a high resistance reduction effect, and a resistance reduction of about 20% at the maximum was obtained at Re = 20000 in the solution.
(2) By using a net with a hole diameter of 0.3 mm, fibers can be recovered from the suspension, and can be recycled and has a low environmental impact.

Claims (5)

A resistance reducing agent that reduces the resistance of the fluid flowing in the pipe,
Made of plant-derived fibers,
A resistance reducing agent having an average fiber length of 0.3 to 2.5 mm and an average aspect ratio of 70 to 120.
The resistance reducing agent according to claim 1, wherein the plant-derived fiber has a Young's modulus of 15 to 28 GPa.
The resistance reducing agent according to claim 1, wherein the plant-derived fiber is a bamboo-derived fiber.
A fluid control method for reducing the resistance of a fluid flowing in a pipe,
The fluid control method according to claim 1, wherein the resistance reducing agent according to claim 1 is mixed before the fluid is circulated in the pipe.
  The fluid control method according to claim 4, wherein a concentration of the plant-derived fiber with respect to the fluid is 2000 to 10,000 ppm.

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