Low-temperature DPF cleaning solution and preparation method thereof

Abstract

The invention discloses a low-temperature DPF cleaning solution and a preparation method thereof, and belongs to the field of cleaning solutions. The DPF cleaning fluid comprises the following components in parts by mass: 30-40 parts of a freezing point reducing auxiliary agent, 1-5 parts of a surfactant, 1-5 parts of a wetting agent, 1-5 parts of a pH regulator, 0.1-0.5 part of a defoaming agent, 1-5 parts of a chelating dispersant and 50-60 parts of a solvent, wherein the freezing point reducing auxiliary agent is one or two of ammonium salt or amine substances. The cleaning fluid prepared through the synergistic effect of all the components has the following effects that the normal-temperature cleaning effect is good, and the cleaning efficiency at the normal temperature is larger than or equal to 70%; 2, freezing is avoided at low temperature, the freezing point is less than or equal to-20 DEG C, and the cleaning work can be continued at low temperature in winter; the low-temperature cleaning effect is good, the cleaning efficiency at-20 DEG C is larger than or equal to 50%, and it is ensured that the cleaning agent still has certain cleaning performance at the low temperature.

Description

Technical Field

[0001] This invention belongs to the field of cleaning fluids, specifically relating to a low-temperature DPF cleaning fluid and its preparation method. Background Technology

[0002] With the implementation of the China VI B emission standard, the emission limits for motor vehicles are becoming increasingly stringent, with higher requirements for PM and PN indicators in vehicle exhaust. To meet these emission limits, diesel vehicles are equipped with DPF (Diesel Particulate Filter) systems. DPFs have a high filtration efficiency for particles, reaching 60%–90%. However, during the filtration process, particulate matter within the DPF can cause an increase in exhaust back pressure. When the exhaust back pressure reaches 16–20 kPa, diesel engine performance begins to deteriorate. Therefore, it is necessary to periodically remove particles from the DPF channels to restore the DPF to its original working condition. Vehicles have built-in regeneration control systems that can effectively remove accumulated combustible mixtures such as CH4, but they have a significant effect on metallic ash. When non-combustible ash accumulates to a certain level, the DPF needs to be disassembled and regenerated.

[0003] DPF regeneration technology is basically finalized, with two main approaches: one is physical ash removal after high-temperature sintering of the DPF; the other is reverse high-pressure rinsing. Both methods are common in China. However, high-temperature sintering technology has low barriers to entry and focuses solely on cleaning speed, lacking environmental protection measures, resulting in significant environmental pollution and high energy consumption. High-pressure rinsing is also quite mature in China, but due to the special structure of the DPF and limitations of the operating environment, cleaning is often not thorough enough, leading to problems and unclear cleaning effects, especially in winter. In northern regions, as temperatures drop, many cleaning solutions freeze and lose their cleaning function, requiring continuous heating to maintain cleaning effectiveness. This method not only increases energy consumption but also significantly reduces the cleaning effect of the solution. Summary of the Invention

[0004] Purpose of the invention: The first purpose of this invention is to provide a low-temperature DPF cleaning fluid with excellent cleaning effect at low temperatures. The second purpose of this invention is to provide a method for preparing the above-mentioned low-temperature DPF cleaning fluid.

[0005] Technical solution: The low-temperature DPF cleaning fluid of the present invention is characterized in that it comprises the following components by weight: 30-40 parts of freezing point lowering agent, 1-5 parts of surfactant, 1-5 parts of wetting agent, 1-5 parts of pH adjuster, 0.1-0.5 parts of defoamer, 1-5 parts of chelating dispersant and 50-60 parts of solvent, wherein the freezing point lowering agent is one or two of ammonium salts or amines.

[0006] Furthermore, the ammonium salt includes one or more of ammonium acetate or ammonium formate; the amine includes one or more of formamide or urea.

[0007] Furthermore, the freezing point lowering agent also includes low molecular weight alcohols; the low molecular weight alcohols include one or more of methanol, ethanol, ethylene glycol, or glycerol.

[0008] Furthermore, the surfactant is one or more of propylene glycol block polyether, alkylphenol polyoxyethylene ether, or glyceryl monostearate.

[0009] Furthermore, the wetting agent is a nonionic wetting agent, preferably one or more of octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, polyethylene glycol, or octanol.

[0010] Further, the pH adjuster is one or more of triethanolamine, 2-amino-2-methyl-1-propanol or isopropanolamine.

[0011] Furthermore, the chelating dispersant is an organophosphate, preferably one or more of ethylenediaminetetramethylenephosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, and aminotrimethylenephosphonic acid.

[0012] Furthermore, the defoamer is an organosilicon defoamer; the solvent is pure water.

[0013] The preparation method of the low-temperature DPF cleaning solution of the present invention comprises the following steps: adding surfactant, chelating dispersant, wetting agent and freezing point lowering agent into a reaction vessel, stirring, adding solvent, defoamer and pH adjuster, and stirring and mixing again to obtain the solution.

[0014] Invention Principle: The main components of DPF ash are inorganic salts and oxides such as calcium, magnesium, zinc, and sulfur, and a small amount of large oily organic particles from fuel additives. This ash accumulates and causes blockages in the DPF. This invention utilizes a chelating dispersant that reacts with the metal salt ions, removing most of them. Simultaneously, the compatibility of the surfactant with the oily organic matter dissolves some of the large organic particles, effectively removing the ash. A pH adjuster adjusts the pH of the cleaning solution to 8-9, effectively protecting the aftertreatment system and preventing corrosion. A freezing point lowering agent lowers the freezing point of the cleaning solution to below -20°C, meeting the requirements for cleaning operations under special conditions.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The low-temperature DPF cleaning agent of the present invention cleans DPF ash with a cleaning efficiency of ≥70% at room temperature; (2) The cleaning agent of the present invention does not freeze at low temperature, with a freezing point of ≤-20℃, which can ensure that the cleaning work can continue at low temperatures in winter; (3) The cleaning efficiency of DPF ash at low temperature is ≥50% at -20℃, ensuring that it still has certain cleaning performance at low temperatures. Detailed Implementation

[0016] The present invention will now be further described with reference to specific embodiments.

[0017] Example 1: The components and dosage of the low-temperature DPF cleaning solution described in this example are shown in Table 1 below.

[0018] Table 1. Components and dosage of the low-temperature DPF cleaning solution in Example 1.

[0019]

[0020]

[0021] The above preparation method is as follows: according to Table 1, add surfactant, chelating dispersant, wetting agent and freezing point lowering agent into reaction vessel, stir for 30 min, then add solvent, defoamer and pH adjuster, stir again for 30 min to mix and obtain the product.

[0022] Example 2: The components and dosage of the low-temperature DPF cleaning solution described in this example are shown in Table 2 below.

[0023] Table 2. Components and dosage of the low-temperature DPF cleaning solution in Example 2.

[0024]

[0025] The preparation method is the same as in Example 1.

[0026] Example 3: The components and dosage of the low-temperature DPF cleaning solution described in this example are shown in Table 3 below.

[0027] Table 3. Components and dosage of the low-temperature DPF cleaning solution in Example 3.

[0028]

[0029]

[0030] The preparation method is the same as in Example 1.

[0031] Example 4: The components and dosage of the low-temperature DPF cleaning solution described in this example are shown in Table 4 below.

[0032] Table 4. Components and dosage of the low-temperature DPF cleaning solution in Example 4.

[0033]

[0034] The preparation method is the same as in Example 1.

[0035] Example 5: The components and dosage of the low-temperature DPF cleaning solution described in this example are shown in Table 5 below.

[0036] Table 5. Components and dosage of the low-temperature DPF cleaning solution in Example 5.

[0037]

[0038]

[0039] The preparation method is the same as in Example 1.

[0040] The low-temperature DPF cleaning agent prepared in the above embodiments was tested according to the Q320124KLS 30-2024 (low-temperature type) test method, as detailed in Table 6. The test results of Examples 1-5 show that all indicators of the low-temperature DPF cleaning agent prepared using the above ratios and methods meet the standards.

[0041] Table 6. Low-temperature DPF cleaning agents with different formulations

[0042]

[0043]

[0044] Comparative Example 1: 1 part propylene glycol block polyether, 5 parts alkylphenol polyoxyethylene ether, 5 parts octylphenol polyoxyethylene ether, 5 parts triethanolamine, 0.1 part silicone defoamer, 10 parts ethylenediaminetetramethylenephosphonic acid, 40 parts ethylene glycol (freezing point lowering agent), and 33.9 parts pure water. Freezing point -21℃.

[0045] Comparative Example 2: 1 part propylene glycol block polyether, 5 parts alkylphenol polyoxyethylene ether, 5 parts octylphenol polyoxyethylene ether, 5 parts triethanolamine, 0.1 part silicone defoamer, 10 parts ethylenediaminetetramethylenephosphonic acid, 35 parts glycerol (freezing point lowering agent), and 38.9 parts pure water. Freezing point -22℃.

[0046] In order to achieve the -20℃ freezing point requirement in the comparative example, a large amount of alcohol needs to be added, accounting for 35-40%, which will cause the viscosity of the system to increase. In the actual cleaning process, it will be difficult to rinse the DPF catalyst clean, and the cleaning solution will remain in the equipment, affecting the equipment's performance.

[0047] Cleaning experiments were conducted using the low-temperature DPF cleaning agents prepared in the above embodiments and comparative examples. A DPF device with sufficient ash was disassembled into several equal parts and placed in 1000ml of cleaning agent at room temperature (20℃) and low temperature (-5℃) for 30 minutes. The parts were then rinsed sequentially with the cleaning solution. After rinsing, the DPF device was placed in an oven and dried at 180℃ for 1 hour. The initial mass of the DPF, the mass after adding ash, and the mass after cleaning were recorded. The difference in mass before and after ash removal was calculated to determine the ash removal rate of the DPF. This was used to test the cleaning effect of the low-temperature DPF cleaning agent. The test results are detailed in Table 7.

[0048] Table 7. Low-temperature DPF cleaning agents with different formulations in the examples and comparative examples.

[0049] Test temperature Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 20℃ 79.04％ 74.31％ 75.54％ 78.19％ 70.21％ 57.8％ 58.7％ -5℃ 57.87％ 52.30％ 53.34％ 56.40％ 51.04％ 37.4％ 35.8％

[0050] As shown in Table 7, the low-temperature DPF cleaning agents of Examples 1-5 achieved a cleaning efficiency of 70% at room temperature and 50% at low temperature, demonstrating good cleaning performance at low temperatures. However, Comparative Examples 1 and 2, due to the high boiling point of their freezing point lowering agents, were difficult to volatilize during the cleaning process, and their excessive viscosity resulted in cleaning solution residues remaining in the fine pores of the DPF, leading to a decrease in cleaning effectiveness.

Claims

1. A low-temperature DPF cleaning fluid, characterized in that, The product comprises the following components by weight: 30-40 parts of freezing point lowering agent, 1-5 parts of surfactant, 1-5 parts of wetting agent, 1-5 parts of pH adjuster, 0.1-0.5 parts of defoamer, 1-5 parts of chelating dispersant, and 50-60 parts of solvent, wherein the freezing point lowering agent is one or two of ammonium salts or amines.

2. The low-temperature DPF cleaning fluid according to claim 1, characterized in that, The ammonium salt includes one or more of ammonium acetate and ammonium formate; the amine includes one or more of formamide or urea.

3. The low-temperature DPF cleaning fluid according to claim 1, characterized in that, The freezing point lowering agent also includes low molecular weight alcohols.

4. The low-temperature DPF cleaning fluid according to claim 3, characterized in that, The low molecular weight alcohols include one or more of methanol, ethanol, ethylene glycol, or glycerol.

5. The low-temperature DPF cleaning fluid according to claim 1, characterized in that, The surfactant is one or more of propylene glycol block polyether, alkylphenol polyoxyethylene ether, or glyceryl monostearate.

6. The low-temperature DPF cleaning fluid according to claim 1, characterized in that, The wetting agent is a nonionic wetting agent.

7. The low-temperature DPF cleaning fluid according to claim 1, characterized in that, The pH adjuster is one or more of triethanolamine, 2-amino-2-methyl-1-propanol, or isopropanolamine.

8. The low-temperature DPF cleaning fluid according to claim 1, characterized in that, The chelating dispersant is an organophosphate.

9. The low-temperature DPF cleaning fluid according to claim 1, characterized in that, The defoamer is an organosilicon-based defoamer.

10. A method for preparing a low-temperature DPF cleaning fluid according to any one of claims 1-9, characterized in that, The steps are as follows: Add surfactant, chelating dispersant, wetting agent and freezing point lowering agent to the reaction vessel, stir, add solvent, defoamer and pH adjuster, and stir again to obtain the final product.

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