JP2019116569A - Heat transport medium and heat transport system - Google Patents

Abstract

To properly exhibit antirust effect by an antirust agent in a heat transport medium containing formamide.SOLUTION: In a heat transport medium containing water, formamide, and antirust agent and transporting heat, the antirust agent contains at least one of molybdate and sebacate, and no sulfate, nitrate nor phosphate. Thereby when a material constituting a heat transport medium channel contains an iron-based metal, an antirust effect can be obtained. The antirust agent contains benzotriazole, and no thiazole salt. Thereby when the material constituting the heat transport medium channel contains a copper-based metal, the antirust effect can be obtained.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat transport medium for transporting heat and a heat transport system.

  In a vehicle or the like provided with an energy conversion system, a heat transport system is often provided which transports heat generated during energy conversion by a heat transport medium and releases the heat to the outside of the system. An ethylene glycol aqueous solution is generally used as a heat transport medium, but the ethylene glycol aqueous solution has a high viscosity at low temperature, and the power to make the heat medium flow, such as increasing the size of the heat radiating portion or heat medium piping Cause an increase in

  On the other hand, Patent Document 1 proposes an aqueous solution containing formamide or methylformamide and a rust inhibitor as a heat transport medium having a low viscosity. In Patent Document 1, boric acid, borates, silicic acids, silicates, phosphoric acids, phosphates, nitrites, nitrates, molybdates, triazoles, diazoles, and thiazoles are described as rust inhibitors. There is.

International Publication No. 2015/151818

  However, the antirust agents mentioned in the above-mentioned Patent Document 1 include those which can not obtain an antirust effect when used simultaneously with formamide.

  An object of the present invention is, in view of the above-mentioned point, to properly exhibit the antirust effect by an antirust agent in a heat transport medium containing formamide.

  In order to achieve the above object, the invention according to claim 1 is a heat transport medium containing water, formamide and an anticorrosion agent for transporting heat, wherein the anticorrosion agent is a molybdate And at least one of sebacate, and is characterized by being free of nitrate and phosphate.

  According to the present invention, when an antirust agent is used simultaneously with formamide, an antirust effect can be appropriately exerted on an iron-based metal.

  The invention according to claim 2 is a heat transport medium containing water, formamide, and an antirust agent to transport heat, wherein the antirust agent includes benzotriazole, And, it is characterized in that it does not contain a thiazole salt.

  ADVANTAGE OF THE INVENTION According to this invention, when a rust preventive agent is used simultaneously with formamide, a rust preventive effect can be exhibited appropriately with respect to a copper-type metal.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows the heat transport system which concerns on embodiment of this invention. It is a graph which shows the antirust effect with respect to ferrous metal. It is a graph which shows the rustproofing effect to copper system metal.

  Hereinafter, an embodiment of the present invention will be described based on the drawings. The present embodiment is an application of the heat transport system of the present invention to a cooling system of an engine (internal combustion engine).

  As shown in FIG. 1, the heat transport system of the present embodiment transports the heat of the engine 101 to the radiator 102 via the liquid heat transport medium flowing through the heat transport medium flow path 100 forming a closed circuit. Is configured. In the present embodiment, the material constituting the heat transport medium channel 100 contains at least one of an iron-based metal mainly composed of iron and a copper-based metal mainly composed of copper. Iron-based materials include iron and iron alloys, and copper-based metals include copper and copper alloys.

  The engine 101 generates heat by energy conversion. The radiator 102 is a heat exchanger that exchanges heat with the outside air to cool the heat transport medium that has become high temperature by heat exchange with the exhaust heat of the engine 101 to cool the medium.

  The heat transport medium flow path 100 is provided with a pump 103 for circulating the heat transport medium through the heat transport medium flow path 100. The heat transport medium in the heat transport medium channel 100 is circulated from the outlet of the engine 101 to the inlet of the engine 101 via the radiator 102.

  Next, the heat transport medium used in the heat transport system according to the present embodiment will be described. The heat transport medium of the present embodiment is an aqueous solution containing water as a solvent, a solute, and a rust inhibitor.

  The solute is used to lower the freezing point of the heat transport medium. In the present embodiment, formamide is used as the solute. The formamide aqueous solution is a liquid having a lower viscosity than an ethylene glycol aqueous solution generally used as an antifreeze liquid.

  The content of formamide in the heat transport medium is 30 to 70 wt%. When the concentration of formamide is less than 30% by weight, the effect of lowering the freezing point of the heat transport medium is reduced. In addition, when the concentration of formamide exceeds 70 wt%, the viscosity of the heat transport medium becomes too high.

  The anticorrosion agent is used to prevent the corrosion of the metal constituting the piping etc. through which the heat transport medium flows. The anticorrosion agent of the present embodiment can obtain an anticorrosion effect on iron-based metals and copper-based metals.

  In the present embodiment, the heat transport medium contains a plurality of rust inhibitors. In the present embodiment, in the heat transport medium, the concentration per rust inhibitor is 0.2 wt% or more, and the total concentration of the plurality of rust inhibitors is 10 wt% or less. When the concentration per corrosion inhibitor is less than 0.2 wt%, the corrosion inhibiting effect can not be sufficiently exhibited. In order to obtain a sufficient antirust effect, the concentration per rust inhibitor is desirably 0.5 wt% or more, and more desirably 1.0 wt% or more. In addition, when the total concentration of the rust inhibitor exceeds 10 wt%, the viscosity becomes too high.

  The rust inhibitor of the present embodiment contains at least one of molybdate or sebacate, and does not contain sulfate, nitrate and phosphate. Molybdate and sebacate exhibit high anticorrosion effects on iron-based metals when used simultaneously with formamide. Molybdate and sebacate salts include alkali metal salts, alkaline earth metal salts, amine salts and ammonium salts. On the other hand, when used together with formamide, sulfates, nitrates and phosphates have a low antirust effect on iron-based metals or no antirust effect. In addition, since nitrite is considered to have a low antirust effect or no antirust effect on an iron-based metal as in the case of nitrate, it is desirable that the antirust agent does not contain nitrite. Moreover, since phosphoric acid is considered to have a low antirust effect or no antirust effect on an iron-based metal similarly to phosphate, it is desirable that the antirust agent does not contain phosphoric acid.

  Here, the anticorrosion effect to iron-based metals will be described with reference to FIG. Fig. 2 shows that a magnetic material (FeLaSi), which is an iron-based metal, and a substance generally used as an anticorrosion agent for iron are added to a formamide aqueous solution (concentration 50 wt%) and kept in a thermostatic chamber at 25 ° C. Shows the results of observing the progress of corrosion of the magnetic material. The concentration of each substance was 0.5 wt%, 1.0 wt%, and 2.0 wt%. In FIG. 2, the case where the entire magnetic material is corroded is indicated by x, the case where about half of the magnetic material is corroded is indicated by Δ, and the case where only a part of the magnetic material is corroded is indicated by ○.

  As shown in FIG. 2, sodium molybdate (molybdate) and sodium sebacate (sebacate) exhibited high anti-corrosion effects on iron-based metals. In particular, sodium molybdate showed high antirust effect at any concentration.

  On the other hand, as shown in FIG. 2, sodium nitrate (nitrate), zinc nitrate (nitrate), sodium sulfate (sulfate) and zinc sulfate (sulfate) cause corrosion of the entire surface of the magnetic material within one day after the start of the test. did. Sodium polyphosphate (phosphate) did not corrode for several days, but after one week the entire surface of the magnetic material corroded.

  In addition, the anticorrosion agent of the present embodiment contains benzotriazole, and does not contain a thiazole salt. Benzotriazole exerts a high anticorrosion effect on copper-based metals when used simultaneously with formamide. The benzotriazoles include 1H-benzotriazole, 5-methyl-1H-benzotriazole, phenyl-1,2,3-triazole, 2-naphthotriazole, 4-nitrobenzotriazole. On the other hand, when used simultaneously with formamide, the thiazole salt has a low antirust effect or no antirust effect on a copper-based metal. Since thiazole is also considered to have a low rusting effect or no rusting effect on an iron-based metal, similarly to the thiazole salt, it is desirable that the rusting agent does not contain thiazole.

  In FIG. 3, brass which is a copper-based metal and a substance generally used as a rust inhibitor for copper are added to an aqueous solution of formamide (concentration 50 wt%), and allowed to stand in a thermostat at 50 ° C. It shows the results of observing the progress of corrosion. The concentration of each substance was 1.0 wt% and 2.0 wt%. In FIG. 3, the case where the corrosion of brass is observed is indicated by x, and the case where the corrosion of brass is not observed is indicated by ○.

  As shown in FIG. 3, 1H-benzotriazole and 5-methyl-1H-benzotriazole had high antirust effects on copper-based metals. On the other hand, mercaptobenzothiazole sodium (thiazole salt) did not have an antirust effect on copper-based metals.

  In the embodiment described above, the antirust agent of the heat transport medium contains at least one of molybdate and sebacate having a high antirust effect on the iron-based metal when used simultaneously with formamide. Also, it does not contain sulfate, nitrate and phosphate, which have a low antirust effect on ferrous metals. Thereby, when the material which comprises the heat transport medium flow path 100 contains an iron-type metal, an antirust effect can be exhibited appropriately.

  Further, in the present embodiment, the antirust agent of the heat transport medium contains benzotriazole having a high antirust effect to the copper-based metal when used simultaneously with formamide, and to the copper-based metal. It does not contain thiazole salt, which has a low antirust effect. Thereby, when the material which comprises the heat transport medium flow path 100 contains a copper-type metal, an antirust effect can be exhibited appropriately.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present invention.

  (1) Although the said embodiment demonstrated the example which employ | adopted the engine 101 as a heat source, a heat source is not limited to this. For example, as a heat source, a fuel cell, a battery, an inverter or the like may be employed.

  (2) In the above embodiment, at least one of molybdate or sebacate and benzotriazole are contained, and nitrite, nitrate, phosphoric acid, phosphate, thiazole and thiazole salt are contained. No antirust agent was described. Not limited to this, when any of iron-based metals and copper-based metals is contained as the material constituting the heat transport medium channel 100, a rust inhibitor corresponding to each metal is selected and used. May be

  For example, when an iron-based metal is used as a material constituting the heat transport medium channel 100, at least one of molybdate or sebacate is included, and sulfate, nitrate, and phosphorus are included. A rust inhibitor which does not contain an acid salt can be used. In addition, when a copper-based metal is used as a material constituting the heat transport medium channel 100, a rust inhibitor which contains benzotriazole and does not contain a thiazole salt can be used. .

100 heat transport medium flow path 101 engine (heat source)
102 Radiator (heat radiation part)
103 pumps

Claims (9)

A heat transport medium containing water, formamide and an antirust agent to transport heat,
The antirust agent contains at least one of molybdate and sebacate and is free of sulfate, nitrate and phosphate. A heat transport medium containing water, formamide and an antirust agent to transport heat,
The antirust agent contains benzotriazole and is a heat transport medium which does not contain a thiazole salt.   The heat transport medium according to claim 1, wherein the rust inhibitor contains benzotriazole and does not contain a thiazole salt.   The heat transport medium according to any one of claims 1 to 3, wherein the content of the antirust agent is 0.2 wt% or more per type.   The heat transport medium according to any one of claims 1 to 4, wherein the content of the rust inhibitor is 10 wt% or less.   The heat transport medium according to any one of claims 1 to 5, wherein the content of formamide is 30 to 70 wt%. A heat transport medium according to claim 1;
And a heat transport medium channel (100) through which the heat transport medium flows.
The heat transport system, wherein the material that constitutes the heat transport medium flow path contains an iron-based metal. A heat transport medium according to claim 2;
And a heat transport medium channel (100) through which the heat transport medium flows.
The heat transport system in which the material which comprises the said heat transport medium flow path contains copper-type metal. A heat transport medium according to claim 3;
And a heat transport medium channel (100) through which the heat transport medium flows.
The heat transport system according to claim 1, wherein the material of the heat transport medium flow path includes an iron-based metal and a copper-based metal.

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