A DPF cleaning material and its preparation method

Abstract

The present invention discloses a DPF cleaning material and a preparation method thereof, comprising the following steps: dissolving starch in water to prepare a starch solution with a concentration of 1-3 wt%, adding amylase to the starch solution for decomposition, then adding lauryl polyoxyethylene ether and heating at 60-80 °C for 20-40 min, and after completion, cooling to room temperature to obtain a first product; mixing nano-titanium dioxide powder and nano-zinc oxide powder according to a mass ratio of 1:1, then adding them to an organic alcohol solution for ultrasonic dispersion, filtering the obtained solution, and taking the filtrate as a second product; mixing the above-mentioned first product and second product in an amount ratio of 1:1-2, then placing them in a water bath at 30-35 °C and stirring, adding a complexing agent and an inhibitor in sequence during the stirring until completely dissolved, and after the solution is cooled to room temperature, adding a pH regulator to adjust the pH of the obtained solution to 3-6. The cleaning material of the present invention can effectively improve the cleaning efficiency and ensure the high-efficient operation of the DPF system.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of DPF cleaning materials. Specifically, it relates to a DPF cleaning material and a preparation method thereof. Background Art

[0002] With the continuous introduction of new diesel vehicle emission regulations, the improvement of national environmental protection policy requirements, the increasingly strict limits of motor vehicle emission standards, and the formal implementation of National VI a, the emission requirements are more stringent than those in the National IV and V stages. The limit value of PM (particulate matter) in the National VI a emission standard is tightened, and the limit of PN (particle number) is added in the National VI b stage. To meet the regulatory requirements, the whole vehicle must be equipped with a DPF (diesel particulate filter), which is a part of the post-treatment system of a National VI diesel engine. It mainly adsorbs particulate matter in the exhaust gas, such as particulate matter, hydrocarbons, nitrogen oxides, and sulfur, etc., to prevent them from being discharged into the atmosphere and causing environmental pollution. Generally speaking, the DPF first collects carbon particles in the exhaust gas. After reaching a certain amount, it is centrally processed to convert exhaust gas pollutants into pollution-free gases. Although the vehicle itself has a regeneration control system that can effectively remove enriched combustible mixtures such as CH, it has little obvious effect on metal ash. When the non-combustible ash accumulates to a certain extent, the DPF needs to be disassembled and regenerated.

[0003] After long-term use, a large amount of carbon particles and ash will accumulate in the DPF. Because the DPF contains many precious metals and other materials, resulting in high prices, it is a common practice in the industry to clean and recycle the polluted DPF. However, the current DPF regeneration technology has basically taken shape, and the mainstream is divided into two types: one is to physically remove ash after high-temperature sintering of the DPF; the other is reverse high-pressure flushing. Both of these two schemes have been introduced in China. Among them, due to the low technical threshold of high-temperature sintering, it has been introduced more. However, it blindly pursues the cleaning speed, lacks environmental protection measures, causes great environmental pollution, and has high energy consumption. The high-pressure flushing scheme also occupies a certain market in China. However, due to the special structure of the DPF, the cleaning is often not thorough. Moreover, both of the above two cleaning methods require the DPF to be disassembled before cleaning. It not only takes time and effort, but also may damage the insulation layer and gasket of the DPF, and cause a large amount of pollution to the environment, which does not meet the requirements of green development.

[0004] Therefore, for the DPF of diesel vehicles, special cleaning materials need to be used for cleaning. However, the cleaning effect of the existing DPF cleaning materials is not ideal. Summary of the Invention

[0005] The problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a DPF cleaning material and a preparation method thereof. The cleaning material of the present invention can effectively improve the cleaning efficiency and ensure the efficient operation of the DPF system.

[0006] The object of the present invention and the technical problems to be solved are achieved by the following technical solutions.

[0007] The present invention provides a preparation method of a DPF cleaning material, comprising the following steps:

[0008] Dissolve starch in water to prepare a starch solution with a concentration of 1-3 wt%, add amylase to the starch solution for decomposition, then add lauryl polyoxyethylene ether and heat at 60-80 °C for 20-40 min, and after completion, cool to room temperature to obtain a first product;

[0009] Mix nano titanium dioxide powder and nano zinc oxide powder according to a mass ratio of 1:1, then add them to an organic alcohol solution for ultrasonic dispersion, filter the obtained solution, and take the filtrate as a second product;

[0010] Mix the above-mentioned first product and second product in an amount ratio of 1:1-2, then place them in a water bath at 30-35 °C and stir. During the stirring process, sequentially add a complexing agent and an inhibitor until completely dissolved. After the solution cools to room temperature, add a pH regulator to adjust the pH of the obtained solution to 3-6.

[0011] Preferably, the amylase is a mixture of α-amylase and β-amylase according to a mass ratio of 1:1.

[0012] Preferably, the addition amount ratio of the amylase to the starch is 0.01-0.03:1.

[0013] Preferably, the addition amount ratio of the lauryl polyoxyethylene ether to the starch is 0.2-0.4:1.

[0014] Preferably, the organic alcohol includes any one of methanol, ethanol, ethylene glycol, and glycerol.

[0015] Preferably, the ultrasonic conditions are: frequency 80-100 KHz, time 10-15 min.

[0016] Preferably, the complexing agent is one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, citric acid, and sodium citrate.

[0017] Preferably, the inhibitor is at least one of BTA, TTA, and sebacic acid.

[0018] Preferably, the pH regulator is one or more of nitric acid, hydrochloric acid, and malic acid.

[0019] With the above technical solutions, the present invention has at least the following advantages: First, starch is used as a raw material and enzymatically hydrolyzed into small molecules, and then lauryl polyoxyethylene ether is added for modification to obtain a modified starch solution. The obtained modified starch can be better dissolved in water and its structural properties are changed, and the covalent binding ability and van der Waals force therein are enhanced. Second, nanoscale titanium dioxide powder and zinc oxide powder are mixed and dispersed in an organic alcohol solution, and the free-form nanoparticles are filtered to obtain a uniform mixture. After mixing this mixture with the modified starch solution and heating and stirring, the nanoparticles therein can be combined with the compounds in the modified starch solution through covalent binding ability and van der Waals force. The formed mixture has a granular feeling, which can ensure that the dirt on the surface of the DPF is more easily removed by the impact of the nanoparticles when cleaning the DPF. Finally, it is mixed with a complexing agent, a corrosion inhibitor, and a pH regulator to obtain a finished product with stable properties. The cleaning material obtained according to the method of the present invention has good cleaning effect and can also well remove the dirt with strong viscosity on the surface of the DPF.

[0020] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it according to the content of the specification, the following will describe in detail with preferred embodiments of the present invention as follows. Detailed implementation manners

[0021] In order to make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0022] Example 1

[0023] A DPF cleaning material, and its preparation method is as follows:

[0024] Dissolve 100 parts of starch in water to prepare a starch solution with a concentration of 2 wt%, add 2 parts of amylase (a mixture of α-amylase and β-amylase in a mass ratio of 1:1) to the starch solution for decomposition, and then add 30 parts of lauryl polyoxyethylene ether and heat at 70 °C for 30 min. After completion, cool to room temperature to obtain a first product.

[0025] Mix nanoscale titanium dioxide powder and nanoscale zinc oxide powder in a mass ratio of 1:1, then add them to an ethanol solution and perform ultrasonic dispersion at 90 KHz for 10 min. Filter the obtained solution, and take the filtrate as a second product.

[0026] Mix the above first product and second product in a ratio of 1:1, then place them in a 33 °C water bath and stir. During the stirring process, add ethylenediaminetetraacetic acid and the corrosion inhibitor sebacic acid in sequence until completely dissolved. After the solution cools to room temperature, add the pH regulator nitric acid to adjust the pH of the resulting solution to 3 - 6.

[0027] Example 2

[0028] A DPF cleaning material, and its preparation method is as follows:

[0029] Dissolve 100 parts of starch in water to prepare a starch solution with a concentration of 1 wt%. Add 3 parts of amylase (a mixture of α - amylase and β - amylase in a mass ratio of 1:1) to the starch solution for decomposition, then add 20 parts of lauryl alcohol polyoxyethylene ether and heat at 70 °C for 30 min. After completion, cool to room temperature to obtain the first product.

[0030] Mix nano - titanium dioxide powder and nano - zinc oxide powder in a mass ratio of 1:1, then add them to an ethylene glycol solution and perform ultrasonic dispersion at 80 KHz for 15 min. Filter the resulting solution, and take the filtrate as the second product.

[0031] Mix the above first product and second product in a ratio of 1:2, then place them in a 35 °C water bath and stir. During the stirring process, add disodium ethylenediaminetetraacetate and the corrosion inhibitor TTA in sequence until completely dissolved. After the solution cools to room temperature, add the pH regulator hydrochloric acid to adjust the pH of the resulting solution to 3 - 6.

[0032] Example 3

[0033] A DPF cleaning material, and its preparation method is as follows:

[0034] Dissolve 100 parts of starch in water to prepare a starch solution with a concentration of 3 wt%. Add 1 part of amylase (a mixture of α - amylase and β - amylase in a mass ratio of 1:1) to the starch solution for decomposition, then add 40 parts of lauryl alcohol polyoxyethylene ether and heat at 70 °C for 30 min. After completion, cool to room temperature to obtain the first product.

[0035] Mix nano - titanium dioxide powder and nano - zinc oxide powder in a mass ratio of 1:1, then add them to a glycerol solution and perform ultrasonic dispersion at 80 KHz for 15 min. Filter the resulting solution, and take the filtrate as the second product.

[0036] Mix the above-mentioned first product and second product in a ratio of 1:2, then place them in a 30°C water bath and stir. During the stirring process, add citric acid and inhibitor BTA in sequence until completely dissolved. After the solution cools to room temperature, add pH regulator malic acid to adjust the pH of the obtained solution to 3 - 6.

[0037] Example 4

[0038] A DPF cleaning material, and its preparation method is as follows:

[0039] Dissolve 100 parts of starch in water to prepare a starch solution with a concentration of 2 wt%. Add 1 part of amylase (a mixture of α-amylase and β-amylase in a mass ratio of 1:1) to the starch solution for decomposition, then add 20 parts of lauryl alcohol polyoxyethylene ether and heat at 70°C for 30 min. After completion, cool to room temperature to obtain the first product.

[0040] Mix nano-titanium dioxide powder and nano-zinc oxide powder in a mass ratio of 1:1, then add them to an ethylene glycol solution and perform ultrasonic dispersion at 100 KHz for 10 min. Filter the obtained solution, and take the filtrate as the second product.

[0041] Mix the above-mentioned first product and second product in a ratio of 1:1, then place them in a 30°C water bath and stir. During the stirring process, add sodium citrate and inhibitor sebacic acid in sequence until completely dissolved. After the solution cools to room temperature, add pH regulator malic acid to adjust the pH of the obtained solution to 3 - 6.

[0042] Example 5

[0043] A DPF cleaning material, and its preparation method is as follows:

[0044] Dissolve 100 parts of starch in water to prepare a starch solution with a concentration of 2 wt%. Add 2 parts of amylase (a mixture of α-amylase and β-amylase in a mass ratio of 1:1) to the starch solution for decomposition, then add 20 parts of lauryl alcohol polyoxyethylene ether and heat at 60°C for 40 min. After completion, cool to room temperature to obtain the first product.

[0045] Mix nano-titanium dioxide powder and nano-zinc oxide powder in a mass ratio of 1:1, then add them to an ethanol solution and perform ultrasonic dispersion at 100 KHz for 10 min. Filter the obtained solution, and take the filtrate as the second product.

[0046] Mix the above first product and second product in a ratio of 1:2, then place it in a 30°C water bath and stir. During the stirring process, add ethylenediaminetetraacetic acid and corrosion inhibitor TTA in sequence until completely dissolved. After the solution cools to room temperature, add pH regulator hydrochloric acid to adjust the pH of the resulting solution to 3 - 6.

[0047] Example 6

[0048] A DPF cleaning material, and its preparation method is as follows:

[0049] Dissolve 100 parts of starch in water to prepare a starch solution with a concentration of 3 wt%. Add 1 part of amylase (a mixture of α - amylase and β - amylase in a mass ratio of 1:1) to the starch solution for decomposition, then add 20 parts of lauryl alcohol polyoxyethylene ether and heat at 60°C for 20 min. After completion, cool to room temperature to obtain the first product.

[0050] Mix nano - titanium dioxide powder and nano - zinc oxide powder in a mass ratio of 1:1, then add them to a methanol solution and perform ultrasonic dispersion at 90 KHz for 15 min. Filter the resulting solution, and take the filtrate as the second product.

[0051] Mix the above first product and second product in a ratio of 1:2, then place it in a 32°C water bath and stir. During the stirring process, add disodium ethylenediaminetetraacetate and corrosion inhibitor BTA in sequence until completely dissolved. After the solution cools to room temperature, add pH regulator nitric acid to adjust the pH of the resulting solution to 3 - 6.

[0052] Comparative Example 1

[0053] A DPF cleaning material, and its preparation method is as follows:

[0054] Dissolve 100 parts of starch in water to prepare a starch solution with a concentration of 2 wt%. Add 2 parts of amylase (a mixture of α - amylase and β - amylase in a mass ratio of 1:1) to the starch solution for decomposition, then add 30 parts of lauryl alcohol polyoxyethylene ether and heat at 70°C for 30 min. After completion, cool to room temperature to obtain the first product.

[0055] Place the above first product in a 33°C water bath and stir. During the stirring process, add ethylenediaminetetraacetic acid and corrosion inhibitor sebacic acid in sequence until completely dissolved. After the solution cools to room temperature, add pH regulator nitric acid to adjust the pH of the resulting solution to 3 - 6.

[0056] Test Example: Detection of the Effect of Cleaning Materials

[0057] Detection method:

[0058] (1) Detect the air flux of the diesel engine DPF before cleaning, which is called the pre-flux;

[0059] (2) Mix the DPF cleaning material and pure water in a mass ratio of 1:9 and place them in the cleaning tank. Then, place the used diesel engine DPF to be cleaned upside down in the cleaning tank. Let the cleaning material be evenly sprinkled on the surface of the DPF through the sprayer, and clean the diesel engine DPF for 2 hours;

[0060] Clean the diesel engine DPF for 2 hours by evenly spraying the cleaning material on the surface of the DPF through the sprayer.

[0061] (3) Detect the air flux of the diesel engine DPF after cleaning, which is called the post-flux.

[0062] Use the DPF cleaning materials of Examples 1-6 and Comparative Example 1 to clean and detect the diesel engine DPF respectively according to the above method. The detection results are shown in Table 1:

[0063] Table 1

[0064]

[0065] As can be seen from Table 1, after cleaning the diesel engine DPF with the DPF cleaning materials of Examples 1-3, the post-cleaning flux ratio can reach 0.93-1.0, and the cleaning effect is good. The post-cleaning flux ratio of Comparative Example 1 after cleaning the diesel engine DPF is only 0.5, and the cleaning effect is significantly lower than that of Examples 1-6.

[0066] The above is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed methods and technical contents within the scope of the technical solution of the present invention to make equivalent embodiments with equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A preparation method of a DPF cleaning material, characterized in that, It includes the following steps: Dissolve starch in water to prepare a starch solution with a concentration of 1-3 wt%, add amylase to the starch solution for decomposition, then add lauryl alcohol polyoxyethylene ether and heat at 60-80 °C for 20-40 min. After completion, cool to room temperature to obtain the first product; Mix nano-titanium dioxide powder and nano-zinc oxide powder according to a mass ratio of 1:1, then add them to an organic alcohol solution for ultrasonic dispersion, filter the obtained solution, and take the filtrate as the second product; Mix the above first product and second product in an amount ratio of 1:1-2, then place them in a water bath at 30-35 °C and stir. During stirring, add a complexing agent and an inhibitor in sequence until completely dissolved. After the solution cools to room temperature, add a pH regulator to adjust the pH of the obtained solution to 3-6.

2. The preparation method of the DPF cleaning material according to claim 1, characterized in that, The amylase is a mixture of α-amylase and β-amylase in a mass ratio of 1:

1.

3. The preparation method of the DPF cleaning material according to claim 1, characterized in that The addition amount ratio of the amylase to the starch is 0.01-0.03:

1.

4. The preparation method of the DPF cleaning material according to claim 1, wherein, The addition amount ratio of the lauryl alcohol polyoxyethylene ether to the starch is 0.2-0.4:

1.

5. The preparation method of the DPF cleaning material according to claim 1, characterized in that, The organic alcohol includes any one of methanol, ethanol, ethylene glycol, and glycerol.

6. The preparation method of the DPF cleaning material according to claim 1, characterized in that, The ultrasonic conditions are: frequency 80-100 KHz, time 10-15 min.

7. The preparation method of the DPF cleaning material according to claim 1, characterized in that, The complexing agent is one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, citric acid, and sodium citrate.

8. The preparation method of the DPF cleaning material according to claim 1, wherein, The inhibitor is at least one of BTA, TTA, and sebacic acid.

9. The preparation method of the DPF cleaning material according to claim 1, wherein The pH regulator is one or more of nitric acid, hydrochloric acid, and malic acid.

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