JPS62129127A - Absorbent composition for air conditioner or hot water supply system - Google Patents

Abstract

PURPOSE:To suppress the corrosive property of an absorbent without damaging the absorbing capacity thereof, by adding an alkanolamine compound or a morpholine compound and molybdenic acid or its salt to an absorbent consisting of respective chlorides or bromides of lithium and zinc. CONSTITUTION:For example, to an absorbent wherein lithium bromide and zinc. chloride are combine, 0.01-10wt% of a water-soluble alkanolamine compound such as N-butyldiethanolamine or a water-soluble morpholine compound such as morphorine and 0.005-1.5wt% of a molybdenum compound such as solium molybdate are added to prepare an aqueous solution of an absorbent composition. By adding said additives, the corrosive property of the absorbent is suppressed and, therefore, said aqueous solution can be used in a state held to an acidic side showing with absorbing capacity and suitable as the absorbent of an absorbing type air conditioner or a hot water supply system.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to an absorbent composition for an absorption type air conditioner or water heater (hereinafter abbreviated as absorption type air conditioner). More particularly, the present invention relates to an absorbent composition with corrosion inhibiting properties for use in absorption air conditioners.

(B) Conventional technology In particular, in well-known absorption air conditioners that use water as a refrigerant, a neutral lithium bromide aqueous solution has traditionally been used as an absorbent to absorb the water vapor emitted from the evaporator and send it to the generator. This aqueous solution is used at or above pH levels, but since this aqueous solution is corrosive to metals, conventionally anticorrosive agents such as lithium hydroxide, inorganic salts, or benzotriazole are used to suppress this. is proposed.

However, since an aqueous solution of lithium bromide causes crystallization when the salt concentration exceeds 62%, there is a limit to the concentration of lithium bromide when using the aqueous solution for an absorption type air conditioner. It has usually been used at 1 degree below 62%, but it has not been expected to have a satisfactory effect in terms of absorption capacity.

Based on this, one of the applicants further developed a lithium chloride product that can significantly increase the absorption capacity for water vapor emitted from an evaporator compared to conventional absorbents when used in various types of equipment. and/or a highly concentrated absorbent composition in which at least one of zinc chloride and/or bromide is added to the bromide (Japanese Patent Laid-Open No. 57-19
0634 and 5g-64130).

C) Problems to be Solved by the Invention However, as is well known, in the above-mentioned zinc ion-containing aqueous solution, the halogen compound of zinc is precipitated when the pt+ is 4.0 or more. In order to avoid precipitation, the absorbent composition contained as a component must be used with its pH maintained at an acidic level of 4.0 or less.

However, since a stable acidic aqueous solution containing halogen compounds of lithium and zinc is extremely corrosive, when it is used as an absorbent composition for an absorption type air conditioner, the absorption part and liquid distribution part, especially 150 In the concentrating section heated to ~250° C., corrosion is noticeable not only at the container wall contact section but also at its interface and gas phase section. As a result, in addition to pitting and cracking of the equipment itself, secondary hydrogen gas is generated during corrosion, resulting in a decrease in the degree of vacuum in the system or precipitation of zinc compounds, which prevents the air conditioning function from functioning and the equipment from operating normally. This will cause serious damage to the

The inventors of the present invention conducted extensive research in view of the above circumstances, and found that by combining a specific amount of a water-soluble alkanolamine compound or a water-soluble morpholine compound and molybdic acids with the above-mentioned absorbent, the absorption capacity of the above-mentioned absorbent was improved. This invention was completed by developing an absorbent composition that does not impair corrosion and has excellent corrosion inhibiting performance.

(d) Means and effects for solving the problems According to the present invention, an absorbent comprising chloride and/or bromide of lithium and chloride and/or bromide of zinc, and an absorbent for the absorbent. , o, oi ~ 10.0% by weight
at least one base selected from water-soluble alkanolamine compounds and water-soluble morpholine compounds, and at least one molybdenum compound selected from molybdic acid and its salts in an amount of 0.005 to 1.5% by weight ,
An absorbent composition for an air conditioner or water heater comprising water as a medium is provided.

In the composition of the present invention, the component having absorption ability is a combination of lithium chloride and/or bromide and at least one of zinc chloride and bromide, and any combination of these compounds is useful. An absorbent composition having improved absorption capacity for water may include lithium, lithium, etc. in an aqueous solution.
Preferably, zinc, bromine and chlorine ions are included.

Thus, examples of such combinations of absorbents include lithium bromide-zinc chloride, lithium bromide-lithium chloride-zinc chloride, lithium bromide-lithium chloride-zinc bromide, lithium chloride-zinc bromide, and bromide. Examples include lithium-zinc chloride-zinc bromide, lithium chloride-zinc chloride-zinc bromide, and lithium bromide-lithium chloride-zinc bromide-zinc chloride.

The above absorbent is preferably used at a concentration in the aqueous solution of 60% by weight or more, preferably 75±5% by weight. If it is less than 60% by weight, the water absorption capacity will be low and the object of the present invention will not be met, and if it is more than 80% by weight, it will exceed the solubility under normal conditions, resulting in inconveniences in use such as crystallization.

The blending ratio of each component of the absorbent of this invention is appropriately selected depending on the combination of these components, the type of the intended absorption device, the water absorption capacity set at that time, etc.
For example, in an absorbent containing lithium bromide as one component, the weight ratio of lithium bromide to other zinc halides is 1:1.
0.1 to 2.0 In addition, in an absorbent containing lithium chloride as one component, lithium chloride and other zinc halides are prepared in an interlayer ratio of 1:1.05 to 3.09.

The corrosion-inhibiting component of the absorbent composition of the present invention comprises at least one selected from water-soluble alkanolamine compounds or water-soluble morpholine compounds, and at least one selected from molybdic acid or salts thereof.

As the alkanolamine compound used in the composition of this invention, compounds represented by the following formulas 1 to 6 are suitable.

R2NR'OHC formula 1], RN (R' 0H)2 (formula 2), N (R' 0H)a (formula 3), H2NR''NHR' OHC formula 4], 110 C82NHR' OH (formula 5),
H2NR'OR''' (26) Here, R is a hydrogen atom or a lower alkyl group, R' is a lower alkylene group, Rn is a lower alkylene group, and Rn is a lower alkyl group. As the alkyl group, an alkyl group having 1 to 4 carbon atoms (hereinafter C) is used,
The lower alkylene group of R' is preferably an alkylene group of 02-3, and the lower alkylene group of Rrr is preferably an alkylene group of 01-4.

Examples of the compound represented by [Formula 1] include monoethanolamine, monopropanolamine, N-methylethanolamine, N-ethylethanolamine, N-ethylethanolamine, and N-ethylethanolamine.
-Propylethanolamine, N-butylethanolamine, N-methylpropanolamine, N-ethylpropanolamine, N-propylpropanolamine, N
-butylpropaturamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N
, N-dipropylethanolamine, N,N-dibutylethanolamine, N,N-dimethylpropanolamine, N.

Examples include N-diethylpropanolamine, N,N-dipropylpropanolamine, N,N-dibutylpropanolamine, and the like.

Examples of the compound represented by (Formula 2) include jetanolamine, dipropanolamine, N-methyljetanolamine, N-ethyljetanolamine, N
-propyl dipropanolamine, N-butyldiethanolamine, N-methyldipropanolamine, N-ethyldipropanolamine, N-propyldipropanolamine, N-butyldipropanolamine, and the like.

Examples of the compound represented by formula C3) include triethanolamine and tripropanolamine.

Examples of the compound represented by [Formula 4] include 2-aminemethylethanolamine, 2-aminoethylethanolamine, 2-aminopropylethanolamine, 2-aminoethylethanolamine, and 2-aminoethylethanolamine.
-aminobutylethanolamine, 2-aminomethylpropanolamine, 2-aminoethylpropanolamine, 2-aminopropylpropanolamine, 2
-aminobutylpropanolamine and the like.

Examples of the compound represented by (Formula 5) include 2-hydroxymethylethanolamine and 2-hydroxymethylpropanolamine.

Examples of the compound represented by [26] include methoxyethylamine, ethoxyethylamine, propoxyethylamine, butoxyethylamine, methoxypropylamine, ethoxypropylamine, propioxypropylamine, butoxypropylamine, and the like.

The morpholine compound used in the composition of this invention includes:
Compounds represented by the following formulas 7 and 8 are suitable [formula 8], where R represents a hydrogen atom or a lower alkyl group, and R// represents a lower alkylene group, respectively. The lower alkyl group is preferably a C1-4 alkyl group, and the lower alkylene group is preferably a C1-4 alkylene group.

The compound represented by [Formula 7] includes, for example, morpholine,
N-methylmorpholine, N-ethylmorpholine, N
-propylmorpholine, N-butylmorpholine and the like.

Examples of the compound represented by [28] include N-amine methylmorpholine, N-aminoethylmorpholine, N-
Examples include aminopropylmorpholine, N-aminobutylmorpholine, and the like.

Either the alkanolamine compound or the morpholine compound is easily dissolved in the aqueous solution containing the absorbent,
i1i over 200℃! Compounds that can be relatively used in actual running in a condensed system are N-methylethanolamine, N-ethylethanolamine, monopropanolamine, N-methylethanolamine, N-ethylethanolamine, monopropanolamine, N, - dibdelethanolamine,
N,N-dimethylpropanolamine, N-butyldiethanolamine, dipropanolamine, triethanolamine, i-rivanolamine, 2
-aminopropylethanolamine, morpholine,
Examples include N-ethylmorpholine and N-aminopropylmolyboline.

The effective amount of the alkanolamine compound or morpholine compound used is 0.01 to 10.0% based on the absorbent.
If this day is below the lower limit, the corrosion inhibiting effect will not be exhibited, and if it is below the lower limit, the use will be at a limit that will not contribute to the corrosion inhibiting effect in the range of use under high temperatures, and there is no meaning.

As already mentioned, the concentration system of the equipment used when using this composition is a high temperature system of 150 to 250°C, and these organic amine compounds are not necessarily sufficiently stable, so when the compounds decompose, gas is generated. This lowers the degree of vacuum in the system, impairing the operating conditions of the device and causing undesirable phenomena. Therefore, in order to fully exhibit the corrosion-inhibiting effect while taking into account the dryness of the mouth, a particularly preferred range of use of the alkanolamine compound or morpholine compound is 0.05 to 7.0% by weight based on the absorbent.

[Lybdic acid or its salt used in this invention]
Molybdic anhydride, alkali metal salts of molybdate, ammonium molybdate, and the like are suitable, and examples of the alkali metal salts of molybdate include sodium molybdate, lithium molybdate, potassium molybdate, and the like.

These addition amounts range from o, oos to 1.5 to the absorbent.
%, more preferably 0.01 to 0.15% by weight. If the amount is less than the above range, it will not contribute to an effective corrosion inhibition effect, and near the upper limit it will contribute to the best steady corrosion inhibition effect, but even if it is added above the limit, better results cannot be expected. Molybdenum-containing components tend to precipitate in highly concentrated absorbent aqueous solutions.

In the composition of the present invention, the amine compound and the molybdenum compound are blended in arbitrary proportions within the effective amount ranges described above.

The composition of the present invention is preferably prepared and added as an aqueous solution in which the absorbent and corrosion inhibitor components are mixed in advance. Alternatively, it may be added supplementally as an aqueous solution.

The composition of the present invention is used in a conventionally known absorption type air conditioner or water heater, in which moisture is absorbed in the absorption section, and then the concentration is adjusted in the concentration section.
It is reintroduced to an appropriate point in the circulatory system leading to the absorption section.

The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereby.

(E) Examples Example 1 An aqueous solution of the absorbent composition of the present invention was prepared using the prescribed amounts of absorbent components and corrosion inhibiting components in the combinations shown in the table below, and each of the above was tested using the following test method. The corrosion rate of the aqueous solution was measured. The results are shown in the table below along with comparative examples. Comparative examples include those using only one of the alkanolamine compounds and molybdates as corrosion inhibiting ingredients, and those using known corrosion inhibitors for general industrial water systems other than the above (laurylamine, sodium gluconate, The above results are shown for an aqueous solution of 1-hydroxy-1-ethylidene diphosphonic acid) in combination with molybdate.

Further, in the table, the amount (%) of the corrosion inhibiting component added is % by weight relative to the absorbent.

〔Test method〕

A glass tube with one side sealed made of Pyrex glass (inner diameter 5
mm5 outer diameter 7mm x length 250mm> test piece [Material:
carbon steel] and the above absorbent composition aqueous solution was added to
1 injection, degas for 3 minutes with a vacuum pump, and melt-seal the glass tube under reduced pressure. Put this sealed tube in an autoclave for 200 minutes.
The test is conducted under high temperature conditions of ℃±1℃ for 7 days. The test is performed when the test piece is fully immersed in the test liquid (test piece size: 4
The test was carried out for each of the test pieces (X30X 1 mm plate shape) and half immersed in the test solution (test piece size: 4Xioox 1 mm plate shape). After the test, take out the test piece and
After pickling, washing with water, and drying, the weight is measured, and the corrosion rate (mg/, 6 m2·day: MDD) is calculated from the amount of weight loss.

For pickling, the sample was immersed in 15% hydrochloric acid containing an acid bath corrosion inhibitor for 15 seconds.

(The following margins continue on the next page.) As is clear from the above test results, the MDD of the absorbent aqueous solution to which an alkanolamine compound and molybdic acid or its salt were added together is the MDD of the absorbent aqueous solution to which each was added alone. It can be seen that the corrosion inhibition effect is reduced to 1/3 to 1/6 compared to that of 1/3 to 1/6.

In addition, the absorbent composition was changed to a Br/CI ratio of 1 to 5 and a Zn/Li ratio of 1 to 5.
Even if the ratio was varied from 4 to 6, the MDD of the absorbent aqueous solution containing N,N-dibutylethanolamine and molybdic anhydride was 6 to 13 for both full immersion and half immersion, which showed good corrosion inhibition performance. It can be seen that Even if the absorbent concentration of the absorbent aqueous solution changes from 60% to 10% to 80%, the M of the absorbent aqueous solution to which an alkanolamine compound or morpholine compound and molybdic acid or its salt are added
It can be seen that DD has a good corrosion inhibition performance of 6 to 8 in the case of full immersion and 7 to 12 in the case of half immersion.

On the other hand, in an absorbent aqueous solution in which a molybdate salt was added in combination with a general industrial water-based corrosion inhibitor, such a remarkable corrosion inhibiting effect could not be obtained, indicating that the effect was insufficient.

Example 2 Lithium bromide (Li Br ) 187.5 (1,!
500 g of an aqueous absorbent solution was prepared by mixing and stirring 1 m Zn (Zn C+ 2 ) 187.5 (l) and 125 g of water.Molybdic anhydride (MO03) 0.25 g was added to this absorbent aqueous solution as a corrosion-inhibiting component. (l and N, N-
After adding 2.5 g of dibutylethanolamine, 175
The absorbent composition of the present invention having corrosion inhibiting performance was prepared by heating and stirring at .degree.

This absorbent composition was subjected to the following tests. That is, in each of the two autoclaves, this absorbent aqueous solution composition and an absorbent aqueous solution to which no corrosion-inhibiting component was added for comparison were put as test liquids, and a test piece [Material: secondary raw steel, 2 dimensions: s] was prepared.
ox 50 x 1.8 mm), so that one sheet was fully immersed in the test liquid and the other sheet was fixed half immersed in the test liquid. After degassing for 30 minutes with a vacuum pump, 150℃±1℃
Tests were conducted for one month at high temperatures. Figure 1 shows the changes in internal pressure during the test period.

After the test, the test piece was taken out, pickled, washed with water, and dried. MDD (mMd m2-day) was measured based on the change in weight. When the test piece was completely immersed in the absorbent composition of the present invention, the result was 2.41. It was found that when the test piece was half immersed, it had a good corrosion inhibition effect of 4.32.

[Consideration]

As is clear from FIG. 1, when an absorbent aqueous solution to which no corrosion-inhibiting component was added was used as the test liquid, the internal pressure of the autoclave increased orally.

This is because H2 gas was generated due to corrosion of the test piece. (Fe+2H◆−I F 6N −1−)−12↑
Or 3Fe +41-120→Fe:+04+4Ht↑
) Due to such an increase in internal pressure, the degree of vacuum within the evaporator decreases, resulting in the inconvenience that sufficient capacity cannot be obtained.

In comparison, when the absorbent composition of the present invention is used as a test liquid, the internal pressure of the autoclave does not change, the degree of vacuum does not decrease, and a good operating condition is maintained.

Furthermore, when the test liquid was observed after the test, a large amount of white precipitate was generated when an absorbent aqueous solution to which no corrosion-inhibiting component was added was used as the test liquid. When used as a liquid, it turned slightly brown, but no precipitate was observed.

(F) Effects of the Invention According to this invention, an alkanolamine compound or a morpholine compound and a molybdic acid or its salt are added to an absorbent aqueous solution in which at least one of ions of lithium and zinc and ions of bromine and chlorine are present. By adding it, the corrosivity of the absorbent is significantly suppressed. This also means that the absorbent can be used while being kept on the acidic side, resulting in extremely high absorption capacity. Therefore, it is most suitable as an absorbent for absorption type air conditioners or water heaters.

[Brief explanation of drawings]

FIG. 1 is a graph showing oral changes in the internal pressure in an autoclave when a test piece is immersed in the composition of the present invention and an aqueous solution of the composition excluding the corrosion-inhibiting component. (A)... When the absorbent composition of the present invention is used; (B)... When the absorbent composition excluding the corrosion inhibitor is used.

Claims (1)

[Scope of Claims] 1. An absorbent consisting of chloride and/or bromide of lithium and chloride and/or bromide of zinc, and a water-solubility of 0.01 to 10.0% by weight with respect to the absorbent. At least one base selected from alkanolamine compounds and water-soluble morpholine compounds;
An absorbent composition for an air conditioner or water heater, comprising 1.5% by weight of at least one molybdenum compound selected from molybdic acid and its salts, and water as a medium. 2. Absorbent is lithium bromide - zinc chloride, lithium bromide -
Lithium chloride - zinc chloride, lithium bromide - lithium chloride - zinc bromide, lithium chloride - zinc bromide, lithium bromide -
The absorbent composition according to claim 1, comprising zinc chloride-zinc bromide, lithium chloride-zinc chloride-zinc bromide, or lithium bromide-lithium chloride-zinc bromide-zinc chloride. 3. The absorbent composition according to claim 1, wherein the concentration of the absorbent is 60 to 80% by weight. 4. The alkanolamine compound has the following formula, R_2NR'OH, RN(R'OH)_2, N(R'O
H)_3, H_2NR″NHR’OH, HOCH_2N
A compound represented by HR'OH or H_2N'OR'' (where R is a hydrogen atom or a lower alkyl group, R' is a lower alkylene group, R'' is a lower alkylene group, and R'' is a lower alkyl group). Absorbent composition according to claim 1. 5. The morpholine compound has the following formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, R is a hydrogen atom The absorbent composition according to claim 1, which is a compound represented by a lower alkyl group, R'' represents a lower alkylene group. 6. The alkanolamine compound is N-methylethanolamine, N-ethylethanolamine, monopropanolamine, N,N-dibutylethanolamine, N,N
The absorbent composition according to claim 1, which is -dimethylpropanolamine, N-butyldiethanolamine, dipropanolamine, triethanolamine, tripropanolamine or N-aminopropylethanolamine. 7. The absorbent composition according to claim 1, wherein the morpholine compound is morpholine, N-ethylmorpholine or N-aminopropylmorpholine. 8. The absorbent composition according to claim 1, wherein the amount of the alkanolamine or morpholine compound added is 0.05 to 7.0% by weight based on the absorbent. 9. Molybdic acid or its salt is molybdic anhydride,
The absorbent composition according to claim 1, which is lithium molybdate, sodium molybdate, potassium molybdate or ammonium molybdate. 10. Claim 1, in which the amount of molybdic acid or its salt added is 0.01 to 0.15% by weight based on the absorbent.
The absorbent composition described in section.