Additives to prevent crystallization and freezing of the urea solution

Abstract

The present invention relates to an additive for preventing crystallization and freezing of urea solution. Specifically, it helps to easily manage the SCR system by inhibiting the crystallization of urea solution used in diesel vehicles and blocking the proliferation of microorganisms to prevent biological sludge.

Description

Technology Field

[0001] The present invention relates to an additive for preventing crystallization and freezing of urea solution used in diesel vehicles, which inhibits the crystallization of urea solution and blocks the proliferation of microorganisms. Background Technology

[0002] Typically, vehicles equipped with diesel engines emit carbon monoxide, hydrocarbons, and nitrogen oxides as exhaust gases, which are one of the major causes of air pollution. To mitigate this resulting air pollution, countries around the world are applying Selective Catalytic Reduction (SCR) systems to diesel vehicles.

[0003] An SCR system is a device that selectively reduces environmental pollutants using a catalyst. Among these, SCR systems using urea solution as a reducing agent are widely used; urea solution reduces nitrogen oxides (NOx) into water (H2O), nitrogen (N2), and carbon dioxide (CO2) for emission.

[0004] There are three main causes of failure in these SCR systems: electrical and mechanical problems of the device, such as sensors, pumps, and modules; wear problems caused by aging and worn parts; and whitening and clogging problems caused by deteriorated urea solution.

[0005] AdBlue is a mixture of urea and water, also known as an aqueous solution of urea or ammonia. According to the international standard ISO 22241, the urea content of automotive AdBlue is 32.5%.

[0006] Since automotive urea solution does not have a low freezing point, it freezes and deteriorates at temperatures below -12°C. Consequently, urea tanks in diesel vehicles are equipped with a preheating device to melt frozen urea crystals. Since the crystals melt upon heat and are injected in a liquid state, driving is not impossible even in sub-zero temperatures. However, the preheating device requires additional components such as heating tubes, temperature sensors, and insulation layers, which significantly increased the cost of each vehicle and complicated the overall vehicle system. Furthermore, despite the high cost, the problem of melting urea crystals has not been completely resolved.

[0007] Specifically, when using a preheating device, it takes a long time to dissolve the urea solution. Therefore, if the vehicle is driven continuously over short distances, the urea solution may not dissolve sufficiently and is injected into the SCR system in a viscous state. This causes the components and injection nozzles of the SCR system to become clogged, and if left in this clogged state for an extended period, it leads to vehicle breakdowns and incurs significant repair costs.

[0008] In addition, there is a problem with the product deteriorating when exposed to high temperatures of 30°C or higher. When exposed to high temperatures, the concentration of the urea solution changes due to the evaporation of moisture or ammonia, which negatively affects the performance of the SCR system and simultaneously promotes the growth of microorganisms in the urea solution, causing corrosion and contamination of the SCR system.

[0009] The issue of urea solution deterioration under such low or high temperature conditions is drawing attention as low-quality urea solution is being distributed due to a recent shortage of domestic supply. The problem to be solved

[0010] The objective of the present invention is to provide a urea additive that prevents the crystallization and freezing of urea used in diesel vehicles and blocks the formation of biological sludge. means of solving the problem

[0011] The present invention relates to an additive for crystallizing urea solution and preventing freezing.

[0012] The present invention provides an additive for preventing crystallization and freezing of urea solution, comprising a dihydrogen oxide, glycols, glycol ethers, ethoxylated cocoalkylamine, and a preservative, wherein the ethoxylated cocoalkylamine is included in an amount of 0.1 to 1.0 weight% relative to the total weight. If the ethoxylated cocoalkylamine is less than 0.1 weight% relative to the total weight, the amount added is negligible and may not produce a crystallization inhibition effect.

[0013] In the present invention, the glycols may be one or more selected from the group consisting of propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, pentamethylene glycol, trimethylene glycol, butylene glycol, and hexylene glycol, but are not limited thereto, and all glycols known in the field may be used.

[0014] In the present invention, the glycol ethers are diethylene glycol phenyl ether, ethylene glycol diphenyl ether, ethylene glycol phenyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, polyethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, polyethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, ethylene glycol mono2-ethylhexyl ether, It may be one or more selected from the group consisting of diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monoallyl ether, propylene glycol monobutyl ether, and dipropylene glycol monobutyl ether, but is not limited thereto, and all glycol ethers known in the field may be used.

[0015] In the present invention, the preservative may be one or more selected from the group consisting of 1,2-benzisothiazolin-3-one and 1,3,5-triazine, but is not limited thereto, and any preservative known in the field may be used.

[0016] In the present invention, the dihydrogen oxide may be included in an amount of 50 to 75 weight%, 50 to 70 weight%, 50 to 65 weight%, 55 to 65 weight%, 55 to 60 weight%, for example, 57.95 weight% based on the total weight, but is not limited thereto.

[0017] In the present invention, the glycols may be included in an amount of 20 to 35 weight%, 20 to 30 weight%, 25 to 30 weight%, 25 to 28 weight%, for example 26.85 weight% based on the total weight, but are not limited thereto.

[0018] In the present invention, the glycol ethers may be included in an amount of 13 to 16 weight%, for example 14.5 weight%, relative to the total weight, but are not limited thereto.

[0019] In the present invention, the weight ratio of the glycols and glycol ethers may be 1.6 to 2.2:1, 1.6 to 2.1:1, 1.7 to 2.1:1, 1.7 to 2.0:1, 1.8 to 2.0:1, for example 1.9:1, but is not limited thereto.

[0020] In the present invention, the preservative may be included in an amount of 0.01 to 0.2 weight%, 0.05 to 0.2 weight%, 0.05 to 0.15 weight%, for example, 0.1 weight% based on the total weight, but is not limited thereto.

[0021] In the present invention, the additive may further include an organic chelating agent, but is not limited thereto.

[0022] The above organic chelating agent may be one or more selected from the group consisting of ethylenediamine and citric acid, but is not limited thereto, and any organic chelating agent known in the field may be used.

[0023] In the present invention, the organic chelating agent may be included in an amount of 0.01 to 0.1 wt%, 0.02 to 0.09 wt%, 0.02 to 0.08 wt%, 0.03 to 0.08 wt%, 0.03 to 0.07 wt%, 0.04 to 0.06 wt%, for example, 0.05 wt% based on the total weight, but is not limited thereto.

[0024] In the present invention, the additive may additionally include a corrosion inhibitor, but is not limited thereto.

[0025] In the present invention, the corrosion inhibitor may be benzotriazole, but is not limited thereto, and any corrosion inhibitor known in the field may be used.

[0026] In the present invention, the corrosion inhibitor may be included in an amount of 0.01 to 0.1 weight%, 0.02 to 0.09 weight%, 0.02 to 0.08 weight%, 0.03 to 0.08 weight%, 0.03 to 0.07 weight%, 0.04 to 0.06 weight%, for example, 0.05 weight% based on the total weight, but is not limited thereto. Effects of the invention

[0027] The additive for preventing crystallization and freezing of urea solution according to the present invention is added to conventional urea solution to prevent the urea solution from crystallizing and freezing. It has the effect of lowering the freezing point of the urea solution to below -12°C and increasing stability by delaying the time of crystal formation even in high-temperature environments. In addition, it has a microorganism removal effect due to the added preservative, thereby functioning to prevent the formation of biochemical sludge in the urea solution. Brief explanation of the drawing

[0028] Figure 1a is a photograph comparing the crystal inhibition effects of the control group and the example at a high temperature (100 ℃) according to Experimental Example 1 of the present invention. FIG. 1b is a photograph comparing the crystal inhibition effects of Comparative Examples 1 to 6 at a high temperature (100 ℃) according to Experimental Example 1 of the present invention. Figure 2 is a photograph comparing the freezing inhibition effect at low temperatures according to Experimental Example 2 of the present invention. Figure 3 is a photograph comparing crystal solubility according to Experimental Example 3 of the present invention. Figure 4 is a photograph comparing the microbial preservative effect according to Experimental Example 4 of the present invention. Specific details for implementing the invention

[0029] The present invention will be explained in more detail below through the following examples. However, these examples are merely illustrative of the invention, and the scope of the invention is not limited by these examples.

[0031] Preparation Example 1. Example: Preparation of urea solution crystallization and freeze prevention additive

[0032] Examples were prepared as described in Table 1 below.

[0033] Components chemical name Examples water dihydrogen oxide 57.95 Glycols Propylene glycol 26.85 Glycol ethers Diethylene glycol phenyl ether 14.50 surfactants Ethoxylated cocoalkylamine 0.50 antiseptic 1,2-benzisothiazolin-3-one 0.05 1,3,5-triazine 0.05 Chelating agent Citric acid 0.05 Corrosion inhibitor benzotriazole 0.05 Total (weight%) 100.00

[0034] Specifically, each raw material was weighed according to the components and contents listed in Table 1. The weighed amounts were added sequentially to the water in a beaker, but the mixture was sufficiently stirred and mixed to ensure homogeneity before adding the next additive, and the temperature was maintained at 30 to 40°C during this process. Subsequently, impurities in the mixture were removed using filter paper, and the urea solution additive was prepared through a degassing process.

[0036] Preparation Example 2. Comparative Example: Preparation of urea solution crystallization and freeze prevention additive

[0037] Comparative Examples 1 to 6 were prepared as described in Table 2 below.

[0038] Components chemical name Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 water dihydrogen oxide 54.00 45.70 54.00 54.00 56.50 56.00 Glycols Propylene glycol 29.90 32.40 26.85 24.95 26.85 26.85 Glycol ethers Diethylene glycol phenyl ether 12.00 17.00 14.50 17.00 14.50 14.50 surfactants Ethoxylated cocoalkylamine 2.0 2.80 2.50 2.00 0.00 0.50 antiseptic 1,2-benzisothiazolin-3-one 0.05 0.05 0.05 0.00 0.05 0.05 1,3,5-triazine 0.05 0.05 0.05 0.00 0.05 0.05 Na-based chelating agents EDTA-4Na 2.00 2.00 1.00 0.00 0.00 0.00 IDS-4Na 0.00 0.00 1.00 2.00 2.00 2.00 Corrosion inhibitor benzotriazole 0.00 0.00 0.05 0.05 0.05 0.05 Total (Weight%) 100.00 100.00 100.00 100.00 100.00 100.00

[0039] Specifically, each raw material was weighed according to the components and contents listed in Table 2. The weighed amounts were added sequentially to the water in a beaker, but the mixture was sufficiently stirred and mixed to ensure homogeneity before adding the next additive, and the temperature was maintained at 30 to 40°C during this process. Subsequently, impurities in the mixture were removed using filter paper, and the urea solution additive was prepared through a degassing process.

[0041] Experimental Example 1. Verification of the effect of preventing crystallization at high temperatures

[0042] The crystallization prevention effect was verified by placing 20 mL of urea solution containing 1% (v / v) of the above Examples and Comparative Examples 1 to 6 into a Petri dish, placing it in a high-temperature environment of 100 ℃, and comparing the time it took for crystals to precipitate. In addition, the experiment was conducted identically with a control group, which was a blank sample urea solution without any added urea additive. The urea solution used was UROX urea solution supplied by Lotte Fine Chemical. The experimental results are shown in Table 3 and Figure 1 below.

[0043] control group Examples Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Decision occurrence time 90 minutes 115 minutes 105 minutes 120 minutes 120 minutes 105 minutes 100 minutes 115 minutes

[0044] As can be seen in Table 3 and Figure 1 above, the additive showed an effect of suppressing crystal formation in urea solution in a high-temperature environment. Specifically, Comparative Examples 2 and 3, in which the weight percentage of surfactant was increased while maintaining a weight ratio of glycols and glycol ethers at 1.9:1, showed the slowest crystal precipitation in a high-temperature environment at 120 minutes, and Comparative Example 6, which used the Example and a Na-based chelating agent, showed the next best stability at high temperatures, with crystal precipitation occurring after 115 minutes.

[0045] On the other hand, Comparative Example 1, in which the weight ratio of glycols and glycol ethers was increased to 2.5:1, and Comparative Example 4, in which it was lowered to 1.5:1, both showed an effect inferior to the example, with crystals precipitating after 105 minutes. In addition, Comparative Example 5, which did not contain a surfactant, showed the lowest crystallization inhibition effect, with crystals precipitating after 100 minutes.

[0047] Experimental Example 2. Verification of the effect of preventing crystallization at low temperatures

[0048] The experiment was conducted by placing 60 mL of urea solution containing 1% (v / v) of the above Examples and Comparative Examples 1 to 6 into a 100 mL glass tube. In addition, the experiment was conducted identically with a control group, which was a blank urea solution without any added urea additives. The urea solution used was UROX urea solution supplied by Lotte Fine Chemical. For the experiment, the 60 mL sample was stored in a freezer, and the freezing state was observed at 2 ℃ intervals. The experimental results are shown in Table 4 and Figure 2 below.

[0049] control group Examples Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Crystal formation temperature -12 ℃ -18 ℃ -16 ℃ -20 ℃ -20 ℃ -20 ℃ -18 ℃ -16 ℃

[0050] As can be seen in Table 4 and Figure 2 above, the additive showed an effect of suppressing crystal formation of urea solution in a high-temperature environment. Specifically, Comparative Examples 2, 3, and 4, which had a higher weight% of surfactant, froze at the lowest temperature of -20 ℃, and the Example and Comparative Example 5, which did not contain surfactant, showed the next best stability at low temperatures and froze at -18 ℃.

[0051] On the other hand, Comparative Example 1, in which the weight ratio of glycols and glycol ethers was increased to 2.5:1, and Comparative Example 6, which used a Na-based chelating agent instead of an organic chelating agent, were frozen at -16 ℃ and showed the lowest freezing inhibition effect.

[0053] Experimental Example 3. Evaluation of Crystal Solubility

[0054] 0.1 g of urea solution crystals precipitated under 100°C conditions were collected and placed in a 50 mL glass tube. Then, 5 mL of urea solution containing 1% (v / v) of the above Examples and Comparative Examples 1 to 6 was added to the glass tube to conduct an experiment to evaluate crystal solubility. The same experiment was also conducted for a control group, which was a blank urea solution without any added urea additives. The urea solution used was UROX urea solution supplied by Lotte Fine Chemical. Solubility was evaluated at 10-minute intervals, and the experiment was conducted at room temperature. The experimental results are shown in Table 5 and Figure 3 below.

[0055] control group Examples Comparative Example 3 Comparative Example 5 Comparative Example 6 Crystal dissolution time 60 minutes 30 minutes 30 minutes 40 minutes 30 minutes

[0056] As can be seen in Table 5 and Figure 3 above, the additive was effective in dissolving the urea solution crystals. Specifically, Comparative Example 3 containing 2.50 wt% of surfactant, and Example and Comparative Example 6 containing 0.5 wt% of surfactant were applied to the crystals, and the crystals were completely dissolved after 30 minutes.

[0057] On the other hand, Comparative Example 5, which did not contain a surfactant, showed the lowest crystal solubility, with crystals remaining after 30 minutes and completely dissolving after 40 minutes.

[0059] Experimental Example 4. Evaluation of Internal Spoilage

[0060] The experiment was conducted by inoculating a culture medium with a urea solution containing 1% (v / v) of the additive according to the above example. The control group was a sample urea solution without the additive. The urea solution used was UROX urea solution supplied by Lotte Fine Chemical. The test strain used was a basic test strain readily available on the market, and it was cultured in an incubator at 35 to 40 ℃ for a total of 4 days. The evaluation results are shown in Table 6 and Figure 4 below, and the evaluation criteria are as follows.

[0061] [metewand]

[0062] 0: No test bacteria detected

[0063] 1: 0 to 9 colonies of the test bacterium detected (however, 0 is not included)

[0064] 2: 10 to 99 colonies of the test bacterium were detected

[0065] 3: 100 to 300 colonies of the test bacterium were detected

[0066] 4: Exceeding 300 colonies of the test bacterium detected (TNTC)

[0067] 0 day 1 day 2 days 3 days 4 days control group 4 (TNTC) 1 0 0 0 Examples 4 (TNTC) 0 0 0 0

[0068] As can be seen in Table 6 and Figure 4 above, the additive showed an effect of preventing the proliferation of microorganisms that cause spoilage. Specifically, the urea solution to which the example containing 0.1 wt% of a preservative was added completely eliminated microorganisms in TNTC within one day. On the other hand, since the urea solution without the additive completely eliminated microorganisms after two days, it can be seen that the urea solution to which the example was added has superior internal spoilage resistance compared to the urea solution without it.

Claims

Claim 1 An additive for crystallization and freezing prevention of urea solution comprising a dihydrogen oxide (CAS No. 7732-18-5), glycols, glycol ethers, ethoxylated cocoalkylamine (CAS No. 61791-14-8), and a preservative, wherein the ethoxylated cocoalkylamine is included in an amount of 0.1 to 1.0 weight% relative to the total weight, and the weight ratio of the glycols and glycol ethers is 1.6 to 2.2:

1. Claim 2 The urea solution crystallization and freeze prevention additive according to claim 1, wherein the dihydrogen oxide is included in an amount of 50 to 75 weight percent relative to the total weight of the additive. Claim 3 The additive for crystallization and freezing prevention of urea solution, wherein the glycols are one or more selected from the group consisting of propylene glycol (CAS No. 57-55-6), dipropylene glycol, tripropylene glycol, polypropylene glycol, monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, pentamethylene glycol, trimethylene glycol, butylene glycol, and hexylene glycol. Claim 4 The urea solution crystallization and freeze prevention additive according to claim 1, wherein the glycols are included in an amount of 20 to 35 weight percent relative to the total weight of the additive. Claim 5 In claim 1, the glycol ethers are diethylene glycol phenyl ether (CAS No. 104-68-7), ethylene glycol diphenyl ether, ethylene glycol phenyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, polyethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, polyethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, An additive for preventing crystallization and freezing of urea solution, comprising one or more selected from the group consisting of ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monoallyl ether, propylene glycol monobutyl ether, and dipropylene glycol monobutyl ether. Claim 6 The urea solution crystallization and freeze prevention additive according to claim 1, wherein the glycol ethers are included in an amount of 13 to 16 weight percent relative to the total weight of the additive. Claim 7 delete Claim 8 The urea solution crystallization and freeze prevention additive according to claim 1, wherein the preservative is one or more selected from the group consisting of 1,2-benzisothiazolin-3-one (CAS No. 2634-33-5) and 1,3,5-triazine (CAS No. 290-87-9). Claim 9 In claim 1, the preservative is a urea crystallization and freeze prevention additive containing 0.01 to 0.2 weight percent based on the total weight of the additive. Claim 10 The additive for crystallization and freezing prevention of urea solution according to claim 1, wherein the additive further comprises one or more organic chelating agents selected from the group consisting of ethylenediamine and citric acid. Claim 11 In claim 10, the above organic chelating agent is a urea solution crystallization and freeze prevention additive containing 0.01 to 0.1 weight% relative to the total weight of the additive. Claim 12 The additive for crystallization and freezing prevention of urea solution according to claim 1, wherein the additive further comprises a corrosion inhibitor, benzotriazole (CAS No. 95-14-7). Claim 13 In claim 12, the corrosion inhibitor is a urea solution crystallization and freeze prevention additive containing 0.01 to 0.1 weight percent based on the total weight of the additive.

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