KR101146708B1 - Antifreezing solution for urea and method for preparing the same - Google Patents

Abstract

PURPOSE: An anti-freezing agent for urea solution and a manufacturing method thereof are provided to safely store and transfer without freezing in winter. CONSTITUTION: An anti-freezing agent for urea solution comprises polyvinyl alcohol as water-soluble polymer including hydroxyl group and acetate group in block type and distilled water. A manufacturing method of an anti-freezing agent for urea solution comprises the following steps: adding water soluble polymer which has polymerization rate of 1500-2500 and saponification degree of 70-90 mole% in the distilled water; and maintaining the mixture with a condition when the mixture reaches up to 80-100 deg. Celsius for half an hour to 2 and a half hours while stirring.

Description

Urea water freezing prevention solution and its manufacturing method {ANTIFREEZING SOLUTION FOR UREA AND METHOD FOR PREPARING THE SAME}

The present invention provides a urea water freezing prevention solution and a method for producing urea water ((NH ₂ ) ₂ CO? H ₂ O), in particular, a high concentration of urea water stably even in cold weather, such as winter, etc. It is about.

The technique of removing NOx using urea water ((NH ₂ ) ₂ CO? H ₂ O) has been widely applied to industrial sites.

Spraying urea resin solution to thermally decompose at a temperature of 900 to 1100 ℃ to decompose into ammonia and isocyanic acid as shown in the following formula (1).

Formula 1

(NH ₂ ) ₂ CO? H ₂ O ---------> NH ₃ + HCNO

In this case, when the NOx-containing gas is injected, a reduction reaction with ammonia gas is converted into harmless nitrogen and water as shown in Chemical Formula 2 below.

Formula 2

2NH ₃ + NO + NO ₂ ---------> 2N ₂ + 3H ₂ O

The remaining isocyanate gas is converted back to ammonia using a catalyst and used for NOx removal.

Formula 3

4HNCO + 4NO + O ₂ ---------> 4N ₂ + 4CO ₂ + 2H ₂ O

Such urea water is difficult to store and transport due to precipitation of crystals at low outside air temperatures in winter when used at high concentrations (eg, 30-40%), and also causes considerable difficulties in field use.

Korean Patent No. 10-0511565 (registered on August 24, 2005, titled "Silicone Water-Based Water-Repellent Emulsion Having Freeze Stability, Patent Document 1))

The present invention has been made to solve the problems of the prior art, the object of the present invention is stable in cold weather such as urea water ((NH ₂ ) ₂ CO? H ₂ O), especially high concentration urea water in winter The present invention provides a solution for preventing urea water freezing that can be stored and transported.

Another object of the present invention is to provide a method for producing the above-mentioned solution for freezing urea water.

In order to achieve the above and other objects, the present invention is to stably store and transport urea water ((NH ₂ ) ₂ CO? H ₂ O), especially high concentration urea water without freezing even in cold weather, such as winter time, for example. It provides a urea water freeze protection solution.

The urea water of the present invention is the freezing point for each concentration and the crystal precipitation temperature for each concentration are as follows.

Freezing point by concentration

40% Liquid: minus 4 ℃

30% Liquid: minus 10 ℃

20% Liquid: minus 12 ℃

Crystal precipitation temperature by concentration

30% Liquid: 0 ℃

40% Liquid: 10 ℃

The urea water freezing prevention solution according to the present invention includes polyvinyl alcohol as a water-soluble polymer including a moiety in which a hydroxyl group and an acetate group in a molecule are in a block type as shown in the following formula (4). At this time, the water-soluble polymer and distilled water is mixed in a weight ratio of approximately 1 to 10.

Formula 4

Where

를 나타내고,A is

Lt; / RTI >

를 나타낸다.B is

Indicates.

If this is shown again, it may be represented by the following Formula 5.

Formula 5

Where

l and n are each an integer of 2 or more,

The degree of polymerization is 1500 to 2500

The degree of saponification is 70 to 90 mole%.

Among the molecules used in the present invention, polyvinyl alcohol as a water-soluble polymer including a moiety in which a hydroxyl group and an acetate group are in a block type is different in structure from conventional polyvinyl alcohol such as the following formula (6).

6

Where

를 나타내고,A is

Lt; / RTI >

를 나타낸다.B is

Indicates.

That is, such a general polyvinyl alcohol has a structure of Formula 7 below.

Formula 7

Polyvinyl alcohol as the water-soluble polymer as described above that can be used in the urea water freeze protection solution according to the present invention is typically K-217-EE, K-217-E, K-220-E, K-420, KH -17 and the like can be mentioned. Here, K-217-EE, K-217-E, K-220-E, K-420 are products of Kuraray Co., Ltd. of Japan, and they are titled Poval (polyvinyl alcohol), The authors are 長野 造 一 (Koichi Nagano), 山根 三 郎 (Yamane Saburo), and 豊 島 賢 太 郞 (Kentaro Toshima), April 10, 1970 (first edition), April 1, 1981 (revised edition), 1989 It is well illustrated in a booklet published on October 01, 1986. In addition, KH-17 is manufactured by Gohsenol of Japan, and these are well displayed on Goshenol's homepage ( http://www.poval.jp/english/poval/appli/ap_1-2.html , http : see //www.gohsenol.com/doc_e/gnrl/gnrl_01.shtml). These may be used alone or in the form of a mixture of two or more thereof.

In addition, the polyvinyl alcohol as the water-soluble polymer as described above which can be used in the present invention preferably has a degree of polymerization of 1500 to 2500 and preferably a saponification degree of 70 to 90 mole%.

The polyvinyl alcohol as such a water-soluble polymer is used in an amount of 0.1 parts by weight or more with respect to 100 parts by weight of urea, more preferably in an amount of 0.1 parts by weight to 0.5 parts by weight. When the polyvinyl alcohol as the water-soluble polymer as described above is used in an amount of less than 0.1 part by weight with respect to 100 parts by weight of urea, it exhibits only an effect similar to that of using general polyvinyl alcohol and has a poor role as a cryoprotectant. When used in an amount of more than 0.5 parts by weight, the same effect as when 0.5 parts by weight is used, so the capacity increase is not meaningful.

The urea water cryoprevention solution used in the present invention has a polymerization degree of 1500 to 2500, saponification degree of 70 to 90 mole%, and a water-soluble polymer having a hydroxyl group and an acetate group in a block type is added to distilled water for 10 minutes to 1 hour. While maintaining the conditions for 30 minutes to 2 hours and 30 minutes when the temperature reaches 80 to 100 ° C with stirring for about 1 hour or more.

The urea water freezing solution according to the present invention allows urea water ((NH ₂ ) ₂ CO? H ₂ O), particularly high concentrations of urea water, to be stably stored and transported without freezing even in cold weather such as winter season. .

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the present invention is not limited to the following examples. The term parts by weight, as used herein, should be understood as values based on 100 parts by weight of urea unless otherwise indicated.

Preparation Example 1

K-217-EE additive solution manufacturing

A water-soluble polymer to be obtained by slowly adding 20 g of K-217-EE (Kuraray, Japan) having a degree of polymerization of 1700, a degree of saponification of 87 mole, and having a hydroxyl group and an acetate group in a block type to 180 g of distilled water. The solution was prepared. In this case, initially, the mixture was slowly warmed with stirring for 30 minutes at room temperature, and the conditions were maintained for 1 hour when it reached 90 ° C. After complete dissolution was completed, it was cooled to give a 10% polymer (K-217-EE) solution.

Manufacturing example  2

K-420 Additive Solution Preparation

A water-soluble polymer solution to be obtained by adding 20 g of K-420 (Kuraray, Japan) having a degree of polymerization of 2000 and a degree of saponification of 78 mole and having a hydroxyl group and an acetate group in a block type was slowly added to 180 g of distilled water. Prepared. In this case, initially, the mixture was slowly warmed with stirring for 30 minutes at room temperature, and the conditions were maintained for 1 hour when it reached 90 ° C. After complete dissolution was completed, it was cooled to give a 10% polymer (K-420) solution.

Example 1-1

Add K-217-EE Solution

300 g of commercially available urea water (40%) was weighed in a 500 ml conical beaker, and then 3 g of 10% K-217-EE solution (K-217-EE) prepared in Preparation Example 1 was weighed in 300 g of urea water. = 0.3 g, 0.1 part by weight) was added. Urea water to which the 10% K-217-EE solution was added was mixed homogeneously using a stirrer. Then, 75 ml of the resultant mixed solution was added to a 100 ml test tube (subzero) and placed in a cooling bath adjusted to a temperature of −5 ° C. (0 hours, 1 hour, 2 hours, 3 hours, 5 hours). ) To visually observe whether the freezing according to the results are shown in Table 1 below.

Example 1-2

The same procedure as in Example 1-1 was carried out except that 9 g (K-217-EE = 0.9 g, 0.3 part by weight) of K-217-EE solution was used.

Example 1-3

The same procedure as in Example 1-1 was conducted except that 15 g (K-217-EE = 1.5 g, 0.5 part by weight) of K-217-EE solution was used.

Comparative Example 1

The same procedure as in Example 1-1 was conducted except that no K-217-EE solution was used.

(Freezing) freezing over time at -5 ℃ Neglect time 0 hours 1 hours 2 hours 3 hours 5 hours Example 1-1 Liquid Liquid Liquid Liquid frost Example 1-2 Liquid Liquid Liquid Liquid Liquid Example 1-3 Liquid Liquid Liquid Liquid Liquid Comparative Example 1 Liquid Liquid Liquid frost frost

Example 2-1

300 g of commercially available urea water (40%) was weighed in a 500 ml conical beaker, and then 3 g of 10% K-217-EE solution (K-217-EE) prepared in Preparation Example 1 was weighed in 300 g of urea water. = 0.3 g, 0.1 part by weight) was added. Urea water to which the 10% K-217-EE solution was added was mixed homogeneously using a stirrer. Then, 75 ml of the obtained mixed solution was placed in a 100 ml test tube (subzero) and placed in a cooling bath controlled at a temperature of −10 ° C. (0 hours, 1 hour, 2 hours, 3 hours, 5 hours). ) To visually observe the freezing according to the results are shown in Table 2 below.

Example 2-2

The same procedure as in Example 2-1 was carried out except that 9 g (K-217-EE = 0.9 g, 0.3 part by weight) of K-217-EE solution was used.

Example 2-3

The same procedure as in Example 2-1 was conducted except that 15 g (K-217-EE = 1.5 g, 0.5 part by weight) of K-217-EE solution was used.

Comparative Example 2

The same procedure as in Example 2-1 was conducted except that no K-217-EE solution was used.

(Freezing) freezing over time at -10 ℃ Neglect time 0 hours 1 hours 2 hours 3 hours 5 hours Example 2-1 Liquid Liquid Liquid frost frost Example 2-2 Liquid Liquid Liquid Liquid frost Example 2-3 Liquid Liquid Liquid Liquid Liquid Comparative Example 2 Liquid Liquid frost frost frost

Example 3-1

300 g of commercially available urea water (40%) was weighed in a 500 ml conical beaker, and then 3 g of 10% K-217-EE solution (K-217-EE) prepared in Preparation Example 1 was weighed in 300 g of urea water. = 0.3 g, 0.1 part by weight) was added. Urea water to which the 10% K-217-EE solution was added was mixed homogeneously using a stirrer. Then, 75 ml of the obtained mixed solution was placed in a 100 ml test tube (subzero) and placed in a cooling bath controlled at a temperature of −15 ° C. (0 hours, 1 hour, 2 hours, 3 hours, 5 hours). ) To visually observe whether the freezing according to the results are shown in Table 3 below.

Example 3-2

The same procedure as in Example 3-1 was carried out except that 9 g (K-217-EE = 0.9 g, 0.3 part by weight) of K-217-EE solution was used.

Example 3-3

The same procedure as in Example 3-1 was conducted except that 15 g (K-217-EE = 1.5 g, 0.5 part by weight) of K-217-EE solution was used.

Comparative Example 3

The same procedure as in Example 3-1 was conducted except that no K-217-EE solution was used.

(Freezing) freezing over time at -15 ℃ Neglect time 0 hours 1 hours 2 hours 3 hours 5 hours Example 3-1 Liquid Liquid frost frost frost Example 3-2 Liquid Liquid Liquid frost frost Example 3-3 Liquid Liquid Liquid Liquid Liquid Comparative Example 3 Liquid frost frost frost frost

Example 4-1

Add K-420 Solution

300 g of commercially available urea water (40%) was weighed in a 500 ml conical beaker, and then 10 g K-420 (Kuraray, Japan) solution prepared in Preparation Example 2 was weighed 300 g. 3 g (K-420 = 0.3 g, 0.1 part by weight) was added. Urea water to which the 10% K-420 solution was added was mixed homogeneously using a stirrer. Then, 75 ml of the obtained mixed solution was placed in a 100 ml test tube (subzero) and placed in a cooling bath controlled at a temperature of −15 ° C. (0 hours, 1 hour, 2 hours, 3 hours, 5 hours). ) To visually observe whether the freezing according to the results are shown in Table 4 below.

Example 4-2

The same procedure as in Example 4-1 was carried out except that 9 g (K-420 = 0.9 g, 0.3 part by weight) of 10% K-420 solution was used.

Example 4-3

A 10% K-420 solution was carried out in the same manner as in Example 4-1, except that 15 g (K-420 = 1.5 g, 0.5 parts by weight) was used.

Comparative Example 4-1

The same procedure as in Example 4-1 was conducted except that no K-420 solution was used.

Comparative Example 4-2

The same procedure as in Example 4-1 was carried out except that 0.4% of P-05 (OCI Co., Ltd.), which was a general PVA, was used instead of the K-420 solution.

Comparative Example 4-3

The same procedure as in Example 4-1 was carried out except that 0.8% of P-05 (OCI Co., Ltd.), which was a general PVA, was used instead of the K-420 solution.

(Freezing) freezing over time at -15 ℃ Neglect time 0 hours 1 hours 2 hours 3 hours 5 hours Example 4-1 Liquid Liquid frost frost frost Example 4-2 Liquid Liquid Liquid Liquid frost Example 4-3 Liquid Liquid Liquid Liquid Liquid Comparative Example 4-1 Liquid frost frost frost frost Comparative Example 4-2 Liquid Liquid frost frost frost Comparative Example 4-3 Liquid Liquid Liquid frost frost

From Tables 1 to 4, polyvinyl alcohol as a water-soluble polymer having a hydroxyl group and an acetate group in a block type in a urea water cryopreservation solution according to the present invention is used in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of urea water. Advantage can be seen. In addition, it can be seen from Table 4 that the effect is more than half the amount than when using a general PVA.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It can be understood that it is possible.

Claims (7)

A urea water freezing prevention solution containing polyvinyl alcohol and distilled water as a water-soluble polymer having a hydroxyl group and an acetate group in a molecule. The solution of claim 1, wherein the degree of polymerization of the polyvinyl alcohol as the water-soluble polymer is 1500 to 2500, and the degree of saponification is 70 to 90 mole%. delete The solution of claim 1 or 2, wherein the polyvinyl alcohol as the water-soluble polymer is used in an amount of 0.1 parts by weight or more with respect to 100 parts by weight of urea water. The solution of claim 1 or 2, wherein the polyvinyl alcohol as the water-soluble polymer is used in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of urea. When a water-soluble polymer having a degree of polymerization of 1500 to 2500 and a degree of saponification of 70 to 90 mole% and a hydroxyl group and an acetate group in a block is added to distilled water, and then reaches 80 to 100 ° C with stirring for 10 minutes to 1 hour. Method for producing a urea water cryopreservation solution comprising maintaining the conditions for 30 minutes to 2 hours 30 minutes. The method for preparing a urea freezing prevention solution according to claim 6, wherein the water-soluble polymer is polyvinyl alcohol having a hydroxyl group and an acetate group in a molecule.