JP2011184513A - Heat transportation medium and heat transportation system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat transportation medium capable of reducing the effects on corrosion even when a metallic piping is used. <P>SOLUTION: The heat transportation medium is used for a heat transportation system for circulating the heat transportation medium between a heat-supplying side system and a heat-utilizing side system through a supplying side passage and a returning side passage. The heat transportation medium is obtained by adding a quaternary ammonium salt-type surfactant represented by the molecular formula: RN<SP>+</SP>((CH<SB>2</SB>)<SB>l</SB>OH)((CH<SB>2</SB>)<SB>m</SB>OH)((CH<SB>2</SB>)<SB>n</SB>OH)-A<SP>-</SP>(wherein, R is 8-22C alkyl or alkenyl; A<SP>-</SP>is an organic acid ion; and l, m and n are each 1-4) to an aqueous liquid, wherein the proportion of the moles of a halide ion in the aqueous liquid is ≤0.5 of the added moles of the quaternary ammonium salt-type surfactant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat transfer medium that circulates between a heat supply side system and a heat utilization side system to transfer heat (hot and cold) and a heat transfer system using the heat transfer medium.

  For example, in a district cooling and heating system, the length of a pipe for circulating a heat transfer medium (for example, water) from an air supply system to an air conditioner (heat utilization side system) installed in a building on the heat utilization side is It is said that it is several kilometers or more and its water conveyance power is considerably large, which is about 60% to 70% of the running cost of the district cooling and heating system.

  Therefore, as an effective method for reducing the water conveyance power, there has been proposed a method for significantly reducing the fluid friction resistance by using a surfactant aqueous solution exhibiting viscoelasticity as a heat conveyance medium (for example, Patent Document 1, Patent). Document 2, Patent Document 3, and Patent Document 4). In this method, several tens to several thousand ppm of a specific quaternary ammonium salt and an organic acid salt are added to water (for example, tap water) flowing in a pipe as a surfactant with respect to the quaternary ammonium salt. When dissolved so that the number of moles is 5 to 100 times, the surfactant is in water, and the hydrophilic base is arranged around the hydrophobic base to form the micelle, and the micelle has a rod-like form. It is said that it is caused by entanglement in higher order and showing viscoelasticity.

  Examples of quaternary ammonium salts that can be dissolved in water include cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, oleyltrimethylammonium chloride, and oleylbishydroxyethylmethylammonium chloride. These are quaternary ammonium chlorides. It is a salt.

Japanese Patent Publication No. 3-76360 Japanese Patent Publication No. 4-6231 Japanese Patent Publication No. 5-47534 JP-A-8-311431

  In general, it is known that when the concentration of chloride ions (halide ions) in water used as a solvent for the heat transfer medium becomes excessive, the corrosivity to metals increases. The supply-side flow path and the return-side flow path that connect between the heat supply side system and the heat utilization side system are often composed of metal pipes made of carbon steel or the like. When piping is used, excessive amounts of chloride ions can corrode metal piping. For example, according to the Japan Refrigeration and Air Conditioning Industry Association and the Water Quality Guidelines for Refrigeration and Air Conditioning Equipment (JRA-GL 02: 1994), chloride ions are clearly one of the important factors that enhance the corrosivity of water. As a reference value thereof, it is set to 50 mg / L or less for the heat transfer medium (cold water).

  An object of the present invention is to provide a heat transfer medium capable of reducing the influence on corrosion even when a metal pipe is used.

  Another object of the present invention is to provide a heat transfer system that can be used over a long period of time by reducing the influence of corrosion on the piping that defines the supply-side flow path and the return-side flow path.

  The present inventors have focused on halide ions including chloride ions as ions having a great influence on the corrosion of metal pipes. As quaternary ammonium salts, organic acids of quaternary ammonium salts are used instead of halides. By using a salt, good friction reduction can be obtained, and by suppressing the number of moles of halogen ions in the heat transfer medium to a predetermined value or less with respect to the quaternary ammonium salt, the influence of corrosion on the piping Has also been found to be greatly reduced.

  However, the present invention provides a heat transfer medium and a heat transfer system as described below.

The heat transfer medium according to claim 1 of the present invention is a heat transfer medium used in a heat transfer system that circulates the heat transfer medium between a heat supply side system and a heat utilization side system through a supply side channel and a return side channel. A medium,
A quaternary ammonium salt type surfactant in which the heat transfer medium is represented by the following molecular formula:

RN ⁺ ((CH ₂ ) ₁ OH) ((CH ₂ ) _m OH) ((CH ₂ ) _n OH) · A ⁻
(R is an alkyl or alkenyl group of _C 8 _{~C 22;} A ^- is an organic acid ion; l, m, n is 1 to 4)
Is added to an aqueous liquid, and the ratio of the number of moles of halide ions in the aqueous liquid is 0.5 or less with respect to the number of moles of the quaternary ammonium salt surfactant added. Features.

In the heat transfer medium according to claim 2 of the present invention, the quaternary ammonium salt type surfactant added to the aqueous liquid has the following molecular formula:
RN ⁺ ((CH ₂ ) _n OH) ₃ · A ⁻
(R is an alkyl or alkenyl group of _C 8 _{~C 22;} A ^- is an organic acid ion; n is 1 to 4)
It is characterized by being.

In the heat transfer medium according to claim 3 of the present invention, the quaternary ammonium salt type surfactant added to the aqueous liquid has the following molecular formula:
RN ⁺ ((CH ₂ ) ₂ OH) ₃ · A ⁻
(R is an oleyl group; A ^- is salicylate)
It is characterized by being.

Furthermore, a heat transfer system according to claim 4 of the present invention is a heat transfer system for circulating a heat transfer medium between a heat supply side system and a heat utilization side system through a supply side flow path and a return side flow path. ,
The heat carrier medium according to any one of claims 1 to 3, wherein the concentration of the quaternary ammonium salt type surfactant added to the aqueous liquid is 300 to 2000 ppm by weight.

According to the heat carrier medium of claim 1 of the present invention, the following molecular formula is used as the quaternary ammonium salt type surfactant:

RN ⁺ ((CH ₂ ) ₁ OH) ((CH ₂ ) _m OH) ((CH ₂ ) _n OH) · A ⁻
(R is an alkyl or alkenyl group of _C 8 _{~C 22;} A ^- is an organic acid ion; l, m, n is 1 to 4)
Since the organic acid salt is added to the aqueous liquid, it does not contain halide ions, so that the influence of corrosion on the metal pipe can be greatly suppressed and a good friction reducing effect can be obtained. Further, since the ratio of the number of moles of halide ions in the aqueous liquid (heat transfer medium) is 0.5 or less with respect to the number of moles of the added quaternary ammonium salt type surfactant, it is contained in the aqueous liquid. Halide ions are kept low, and the influence of corrosion on metal pipes can be reduced.

Moreover, according to the heat carrier medium of claim 2 of the present invention, the quaternary ammonium salt type surfactant added to the aqueous liquid has the following molecular formula:
RN ⁺ ((CH ₂ ) _n OH) ₃ · A ⁻
(R is an alkyl or alkenyl group of _C 8 _{~C 22;} A ^- is an organic acid ion; n is 1 to 4)
According to the heat transfer medium of claim 3, the quaternary ammonium salt type surfactant has the following molecular formula:
RN ⁺ ((CH ₂ ) ₂ OH) ₃ · A ⁻
(R is an oleyl group; A ^- is salicylate)
Therefore, halide ions are not included as the quaternary ammonium salt surfactant, and the influence of corrosion on the metal pipe can be greatly suppressed, and a good friction reducing effect can be obtained.

  Furthermore, according to the heat transfer system according to claim 4 of the present invention, a quaternary ammonium salt type surfactant that is added to an aqueous liquid using the heat transfer medium according to any one of claims 1 to 3. Since the concentration of is 300 to 2000 ppm by weight, it is possible to largely suppress the influence of corrosion on the metal pipe defining the supply side flow path and the return side flow path, and to obtain a desired friction reducing effect.

1 is a schematic diagram showing a heat transfer system in which a heat transfer medium according to the present invention is used. The schematic diagram which shows the evaluation apparatus used by the Example and the comparative example. The figure which shows the experimental result of the friction reduction effect in an Example and a comparative example.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a heat transfer medium and a heat transfer system using the heat transfer medium according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram illustrating an example of a heat transfer system in which a heat transfer medium according to the present invention is used.

  In FIG. 1, the illustrated heat transfer system includes, for example, a heat supply side system 2 that supplies heat (hot and cold) to a heat transfer medium, a heat use side system 4 that uses the heat of the heat transfer medium, and a heat supply. A supply-side flow path 6 and a return-side flow path 8 that circulate the heat transfer medium through between the side system 2 and the heat utilization side system 4, and the supply-side flow path 6 and the return-side flow path 8 are made of, for example, metal Stipulated by the piping. In this embodiment, a feed pump 10 is disposed in the supply side flow path 6, and an electromagnetic flow meter 12 is disposed in the return side flow path 8. The heat transfer medium is filled in the supply side flow path 6 and the return side flow path 8 defined by piping or the like, and this heat transfer medium is supplied by the action of the feed pump 10 to the supply side flow path 6 and the return side flow path 8. The electromagnetic flow meter 12 is circulated between the heat supply side system 2 and the heat utilization side system 4 through and measures the flow rate of the heat transfer medium flowing through the return side flow path 8.

  Specific examples of the heat supply side system 2 include a gas absorption chiller / heater, an oil absorption chiller / heater, a turbo refrigerator, a boiler, and the like, and specific examples of the heat utilization side system 4 include an air conditioner ( For example, an air handling unit, a fan coil unit, etc.), a heater (eg, a fan convector, a floor heating device, etc.), a heat exchanger unit (eg, a plate heat exchanger, etc.), etc.

  Next, the heat transfer medium used in such a heat transfer system will be described. As the heat transfer medium, an aqueous liquid such as water (tap water) is used, and the quaternary ammonium salt type surfactant is used as the aqueous liquid. Is used.

The quaternary ammonium salt type surfactant added to the aqueous liquid has the following molecular formula:

RN ⁺ ((CH ₂ ) ₁ OH) ((CH ₂ ) _m OH) ((CH ₂ ) _n OH) · A ⁻
(R is an alkyl or alkenyl group of _C 8 _{~C 22;} A ^- is an organic acid ion; l, m, n is 1 to 4)
Specific examples represented by this molecular formula include oleyldi (hydroxyethyl) hydroxypropylammonium salicylate, oleyldi (hydroxyethyl) hydroxypropylammonium naphthoate, oleyldi (hydroxyethyl) hydroxypropyl Examples thereof include one or a mixture of two or more of ammonium salicylate, oleyl di (hydroxyethyl) hydroxypropylammonium naphthoate, and the like.

  Such a quaternary ammonium salt type surfactant is a viscoelastic material in which micelles formed by placing a hydrophilic base at the outer periphery of a hydrophobic base in an aqueous liquid form a rod-like form and are entangled in high order. This viscoelasticity provides a good friction reducing effect. Further, such a quaternary ammonium salt type surfactant contains an organic acid ion as a composition, and this organic acid ion has little influence on the corrosion of metal pipes and corrodes the pipes used in the heat transfer system. Generation can be greatly suppressed.

The quaternary ammonium salt type surfactant added to the aqueous liquid has the following molecular formula:
RN ⁺ ((CH ₂ ) _n OH) ₃ · A ⁻
(R is an alkyl or alkenyl group of _C 8 _{~C 22;} A ^- is an organic acid ion; n is 1 to 4)
And specific examples represented by this molecular formula include one or two of cetyltri (hydroxyethyl) ammonium salicylate, cetyltri (hydroxyethyl) ammonium naphthoate, oleyltri (hydroxyethyl) ammonium naphthoate, etc. The above mixture is mentioned.

This quaternary ammonium salt type surfactant has the following molecular formula:
RN ⁺ ((CH ₂ ) ₂ OH) ₃ · A ⁻
(R is an oleyl group; A ^- is salicylate)
Is more preferable, and a specific example represented by this molecular formula is oleyltri (hydroxyethyl) ammonium salicylate.

  The concentration of the quaternary ammonium salt surfactant added to the aqueous liquid is preferably 300 to 2000 ppm by weight. If the concentration is less than 300 ppm by weight, the amount of addition becomes too small and it is difficult to obtain the desired friction reduction effect. If the concentration exceeds 2000 ppm by weight, the desired friction reduction effect is obtained, but it is excessive. It becomes economically wasteful to be added to.

  Various chemicals may be added to the aqueous liquid used as the solvent in the heat transfer medium. For example, an antifreezing agent such as glycol or alcohol, or a metal pipe corrosion inhibitor such as nitrite, molybdate, or amine may be added.

  In this heat transfer medium, the ratio of the number of moles of halide ions contained in the aqueous liquid to which the quaternary ammonium salt type surfactant is added is based on the number of moles of the quaternary ammonium salt type surfactant added. For example, even when tap water is used as an aqueous liquid, it is 0.5 or less including chloride ions contained in tap water. By setting the ratio of the number of moles of halide ions in the aqueous liquid to 0.5 or less with respect to the number of moles added, the number of halide ions contained in the aqueous liquid decreases, and this also leads to the metal pipe. The effect of corrosion can be reduced. The ratio of the number of moles of halide ions is preferably 0.3 or less with respect to the number of moles added in order to enhance the corrosion inhibition effect of the metal pipe.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples.

  In order to confirm the effect of the present invention, the following experiment was conducted to confirm the friction reduction effect and the influence of metal corrosion on the heat transfer medium of the present invention.

<Measurement of friction reduction effect>
The experiment of the friction reduction effect was performed using the evaluation apparatus shown in FIG. Here, the evaluation apparatus will be described with reference to FIG. In FIG. 2, the evaluation apparatus includes a medium tank 21, and pipes 23, 24, 25, 26 are connected to the medium tank 21, and the heat transfer medium filled in the medium tank 21 is connected to the pipes 23, 24, 25, 26, a friction characteristic measuring unit 27 is provided in connection with the pipe 25. A fine differential pressure gauge 29 is provided in the friction characteristic measuring unit 27, and an electromagnetic flow meter 30 is provided between the pipe 23 and the pipe 24. In the experiment of the friction reduction effect, a heat transfer medium (each sample described later) adjusted to 10 ° C. is filled in the medium tank 21, and the heat transfer medium in the medium tank 21 is piped by the feed pump 22 as indicated by an arrow. The pressure difference of the heat transfer medium flowing through the pipe 25, that is, the pressure difference between the inflow portion and the outflow portion of the friction characteristic measurement unit 27 was measured with the micro differential pressure gauge 29, and the pressure loss ΔP was measured. .

  The friction reduction rate DR (%) when a quaternary ammonium salt surfactant aqueous solution (each sample to be described later) was used as a heat transfer medium was calculated by the following equation (1).

DR (%) = [(ΔPw−ΔPs) / ΔPw] × 100 (1)
△ Pw: Pressure loss when using tap water as heat transfer medium
ΔPs: Pressure loss when a surfactant aqueous solution is used as the heat transfer medium As this friction reduction rate DR (%) is understood from the equation (1), the greater the value, the greater the friction reduction effect. Indicates.

<Measurement of metal corrosion effects>
The following experiment was conducted on the effect of metal corrosion. As a test piece, a material of SS400, size 40 mm (length) × 40 mm (width) × 2 mm (thickness), surface # 800 polished was prepared, and the weight before the corrosion test was measured. The test piece was immersed in a 500 mL beaker mixed with a heat transfer medium (each sample to be described later), and the heat transfer medium in the beaker was stirred at a rotational speed of 750 rpm with a magnetic stirrer. At this time, the heater was heated so that the temperature of the heat transfer medium was 60 ° C. After this immersion state was continued for 10 days, the test piece was taken out, washed with an acid, and then weighed after the experiment. In the evaluation of the corrosion experiment, the difference (weight reduction) between the weight of the test piece before immersion and the weight of the test piece after immersion and acid cleaning was calculated, and the corrosion rate (MDD) [mg / dm ² · day] from the equation (2) Was calculated.

Erosion rate (MDD) = {[(weight of test piece before immersion [g] −weight of test piece after immersion [g]) × 100] / (surface area of test piece [cm ² ] × 1000/100)} / Immersion days [day] (2)
<Sample Example 1>
As a heat transfer medium of Sample Example 1, oleyltri (hydroxyethyl) ammonium salicylate which is a quaternary ammonium salt type surfactant [molecular formula: C ₁₈ H ₃₅ N ⁺ (CH ₂ CH ₂ OH) ₃ · C ₆ H ₄ (OH) (COO ⁻ ); hereinafter referred to as “OTHAS”. ] And various concentrations of sodium chloride added to tap water (chloride ion concentrations 10.0 mg / L, 15.9 mg / L, 26.4 mg / L, 37.0 mg / L) were used. The OTHAS concentration at this time was 800 ppm by weight (molar concentration 1.49 × 10 ⁻³ mol / L). In Example 1, the heat transfer medium having a chloride ion concentration of 10.0 mg / L (molar ratio to the surfactant of 0.19) was used as Example 1, and the chloride ion concentration of 15.9 mg / L (molar to the surfactant) The heat transfer medium having a ratio of 0.30) was set as Example 2, the heat transfer medium having a chloride ion concentration of 26.4 mg / L (molar ratio to surfactant of 0.50) was set as Example 3, and the chloride ion concentration was A heat transfer medium having a molecular weight of 37.0 mg / L (molar ratio of 0.70 to the surfactant) was defined as Comparative Example 1.

<Sample Example 2>
As a heat transfer medium of sample example 2, oleyltri (hydroxyethyl) ammonium chloride which is a quaternary ammonium salt type surfactant [molecular formula: C ₁₈ H ₃₅ N ⁺ (CH ₂ CH ₂ OH) ₃ · Cl ⁻ ; It is written as “OTHAC”. ] And sodium salicylate added to water. The concentration of OTAC at this time was 800 ppm by weight (molar concentration 1.83 × 10 ⁻³ mol / L). The mixing ratio of OTAC and sodium salicylate was 1: 1 by molar ratio. The heat transfer medium of Sample Example 2 was referred to as Comparative Example 2.

<Experimental result>
The experimental result of the friction reduction effect mentioned above is shown in FIG. FIG. 3 is a diagram illustrating the relationship between the flow velocity of the heat transfer medium and the friction reduction rate (DR%) in Examples 1 to 3 and Comparative Examples 1 and 2. As is clear from this experimental result, in any of Examples 1 to 3 and Comparative Examples 1 and 2, a friction reduction rate of 70% to 75% was obtained in the range of flow velocity of 0.5 m / s to 2.5 m / s. It was shown that both have a friction reducing effect.

  Table 1 shows the experimental results of metal corrosion effects.

実施例１〜３及び比較例１における塩化物イオン量は、溶媒として用いた水道水中に含まれているもの及び添加した塩化ナトリウムに起因するものである。また，比較例２における塩化物イオンは、溶媒として用いた水道水中に含まれているものの他に、使用した第四級アンモニウム塩型界面活性剤が塩化物塩であるのでこれに起因するものである。

The amounts of chloride ions in Examples 1 to 3 and Comparative Example 1 are attributed to those contained in tap water used as a solvent and added sodium chloride. In addition, the chloride ion in Comparative Example 2 is attributed to the fact that the quaternary ammonium salt type surfactant used is a chloride salt in addition to those contained in the tap water used as the solvent. is there.

  As is clear from the results of this experiment, when a heat transfer medium having a molar ratio of chloride ions to surfactant of 0.50 or less is used, the corrosion rate of the test piece is slow and the corrosion of chloride ions to the metal. It was confirmed that there was little influence.

  From the above experimental results, it was found that in Examples 1 to 3, it was possible to obtain a sufficient friction reducing effect and to reduce the corrosion influence on the metal.

2 Heat supply side system 4 Heat utilization side system 6 Supply side flow path 8 Return side flow path 10 Feeding pump

Claims (4)

A heat transfer medium used in a heat transfer system for circulating a heat transfer medium between a heat supply side system and a heat utilization side system through a supply side flow path and a return side flow path,
A quaternary ammonium salt type surfactant in which the heat transfer medium is represented by the following molecular formula:

RN ⁺ ((CH ₂ ) ₁ OH) ((CH ₂ ) _m OH) ((CH ₂ ) _n OH) · A ⁻
(R is an alkyl or alkenyl group of _C 8 _{~C 22;} A ^- is an organic acid ion; l, m, n is 1 to 4)
Is added to an aqueous liquid, and the ratio of the number of moles of halide ions in the aqueous liquid is 0.5 or less with respect to the number of moles of the quaternary ammonium salt surfactant added. Characteristic heat transfer medium. The quaternary ammonium salt type surfactant added to the aqueous liquid has the following molecular formula:
RN ⁺ ((CH ₂ ) _n OH) ₃ · A ⁻
(R is an alkyl or alkenyl group of _C 8 _{~C 22;} A ^- is an organic acid ion; n is 1 to 4)
The heat transfer medium according to claim 1, wherein: The quaternary ammonium salt type surfactant added to the aqueous liquid has the following molecular formula:
RN ⁺ ((CH ₂ ) ₂ OH) ₃ · A ⁻
(R is an oleyl group; A ^- is salicylate)
The heat transfer medium according to claim 2, wherein A heat transfer system for circulating a heat transfer medium between a heat supply side system and a heat utilization side system through a supply side flow path and a return side flow path,
A heat transfer medium comprising the heat transfer medium according to any one of claims 1 to 3, wherein the concentration of the quaternary ammonium salt surfactant added to the aqueous liquid is 300 to 2000 ppm by weight. system.

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