CN115006991A - High-conversion-rate vehicle urea solution and preparation method thereof - Google Patents
High-conversion-rate vehicle urea solution and preparation method thereof Download PDFInfo
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- CN115006991A CN115006991A CN202210561519.1A CN202210561519A CN115006991A CN 115006991 A CN115006991 A CN 115006991A CN 202210561519 A CN202210561519 A CN 202210561519A CN 115006991 A CN115006991 A CN 115006991A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2067—Urea
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
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Abstract
The invention discloses a high-conversion-rate automobile urea solution and a preparation method thereof, wherein the high-conversion-rate automobile urea solution comprises the following components in parts by weight: 32-36% of high-purity urea, 1-9% of cyclohexylamine, 1-9% of triethanolamine, 4-11% of DL-methylthiobutanamic acid, 1-5% of an auxiliary agent and the balance of small molecular group water. The invention relates to the technical field of vehicle urea, and particularly provides a high-conversion-rate vehicle urea solution and a preparation method thereof.
Description
Technical Field
The invention relates to the technical field of automobile urea, in particular to a high-conversion-rate automobile urea solution and a preparation method thereof.
Background
The automobile urea is colorless, transparent and clear liquid, is used for reducing nitrogen oxides, can be used as a reducing agent of an SCR (Selective Catalytic Reduction) system, and is reacted with nitrogen oxides in tail gas of diesel vehicles such as heavy trucks, buses and the like by utilizing an automobile urea aqueous solution to generate N2 and H2O to purify the tail gas, so that the discharged nitrogen oxides can reach the discharge standard of the country VI. At present, the national mandatory standard GB29518-2013 requires that the urea content should be 31.8% -33.2%. Currently, GB17691-2018, "pollutant emission limits and measurement methods for heavy-duty diesel vehicles" (sixth stage of china), has been put into practice, and after gas vehicles, urban heavy-duty diesel vehicles also enter the sixth emission stage of china in 1/7 of 2020. Compared with the national emission standard five, the emission limits of nitrogen oxides and particulate matters in the national emission standard six are respectively increased by 77 percent and 67 percent, and the limit requirement of particle quantity (pn) is newly added. In order to reach the six national emission standards, a plurality of exhaust gas after-treatment technologies are generally required to work together, wherein a Selective Catalytic Reduction (SCR) technology is one of the currently widely used exhaust gas treatment technologies, so that the automobile urea belongs to an important consumable. How to enable the automobile urea to react with NOx in tail gas rapidly with NH3 to generate N2 and H2O, reduce urea residues, improve the use efficiency of the urea, reduce the risk that the urea blocks a urea nozzle, become important matters of technical development, and prevent the problems of blocking the urea pump, causing the clamping stagnation of a valve piece in the urea pump, unable pressure building, blocking the urea nozzle, poor injection atomization, easy accumulation and crystallization after being injected into an air pipe, reduction of the efficiency of an SCR catalytic converter and the like.
The traditional SCR system has various reducing agents, wherein the urea aqueous solution as the reducing agent has the advantages of strong reducing capability and low cost, and is widely applied to the SCR system of the mobile pollution source. However, the existing reductant products of the SCR system have the following disadvantages: firstly, the solidification is easy; secondly, the conversion rate is low and scaling is easy to occur; and thirdly, the purity is low. In the process of decomposing and generating ammonia by using a traditional reducing agent product, a byproduct, namely isocyanic acid (HNCO), is easy to polymerize and scale, so that the normal operation of an SCR system is seriously influenced, and the excessive emission of tail gas is caused. Therefore, the research on the novel high-efficiency high-conversion-rate automobile urea solution has very important practical significance.
Currently, only the characteristics of high requirement on the purity of the urea for vehicles are found, and more enterprises only design methods and approaches in terms of the purity of the urea, such as: the Chinese patent of the invention has the name: a preparation method of urea for vehicles has the following patent numbers: 201210003845.7, it discloses a method of urea recrystallization to produce high purity urea, then to produce vehicle urea with high purity water, but the production is energy intensive, the cost is high, and a large amount of mother liquor is wasted. The Chinese patent of the invention has the name: a production process of a tail gas catalytic reducing agent has the following patent numbers: 201010152076.8, which discloses a continuous filtration and ion exchange technique for adsorption exchange of metal and non-metal ions; but the process is complex and the cost is high. The urea for the production vehicles of enterprises is lack of content in the aspect of improving the use and conversion efficiency of products.
Disclosure of Invention
Aiming at the situation, in order to overcome the defects of the prior art, the invention provides the high-conversion-rate automobile urea solution and the preparation method thereof, and the hydrolysis of isocyanic acid is promoted and the occurrence of side reactions is reduced by developing the high-conversion-rate automobile urea, so that the scaling tendency of an SCR system is slowed down, the service life of the SCR system is prolonged, and the research and development level of the automobile urea technology in China is finally improved.
The technical scheme adopted by the invention is as follows: a high-conversion-rate automobile urea solution comprises the following components in percentage by weight: 32-36% of high-purity urea, 1-9% of cyclohexylamine, 1-9% of triethanolamine, 4-11% of DL-methylthiobutanamic acid, 1-5% of an auxiliary agent and the balance of small molecular group water.
As further optimization of the scheme, the high-conversion-rate automobile urea solution comprises the following components in percentage by weight: 32% of high-purity urea, 9% of cyclohexylamine, 9% of triethanolamine, 9% of DL-methylthiobutanamic acid, 3% of an auxiliary agent and 38% of small molecular group water.
As a further optimization of the scheme, the half-range of the magnetic resonance of the water molecular group of the small molecular group water is 50 Hz, and the oxidation-reduction potential is between minus 150 and minus 500.
Further, the auxiliary agent is a mixture of alkyl glucoside and a soot catalytic material.
Further, the weight ratio of the alkyl glucoside to the soot catalytic material is 0.9-1.8: 0.7 to 1.2.
The invention also discloses a preparation method of the high-conversion-rate automobile urea solution, which comprises the following steps:
(1) the preparation process of the micromolecular water comprises the following steps: the water tank is provided with core materials, the core materials comprise tourmaline, medical stone and muyu stone, ultrapure water passes through the water tank to form small molecular group water,
(2) weighing the components in parts by weight; pouring high-purity urea, glycerol, cyclohexylamine and small molecular group water into a stirring kettle in sequence for reaction to prepare mixed raw material liquid;
(3) adding DL-methylthio butyric acid and an auxiliary agent into the mixed raw material liquid, and continuously reacting in a reaction kettle to obtain a vehicle urea solution crude product with high conversion rate;
(4) and (3) filtering and purifying the crude product of the high-conversion-rate automobile urea solution to obtain the high-conversion-rate automobile urea solution.
Further, the reaction conditions in the water tank in the step (1) are as follows: the temperature is 25-35 ℃, and the time is 3-5 h.
Further, the reaction conditions in the reaction kettle in the step (2) are as follows: the temperature is 60-80 ℃.
Furthermore, the filtration in the step (3) adopts an ultra-micro filtration membrane with the membrane pore diameter of 0.3-0.8 μm.
The invention with the structure has the following beneficial effects:
the special automobile urea solution can effectively exert the effect of the automobile urea and prevent the urea from crystallizing. The urea solution has the advantages and practical value, is greatly improved in method or function, has great technical progress, produces good and practical effect, and has enhanced multiple effects compared with the existing vehicle urea solution, thereby being more practical and having wide industrial utilization value;
according to the scheme, a 2-amino-4-methylthio butylamine substance is added into a urea stock solution, so that the urea stock solution has a self-dispersion function and a free radical polymerization termination function, the generation amount of isocyanic acid can be effectively reduced, the hydrolysis of isocyanic acid is promoted, the side reaction is reduced, and meanwhile, small molecular group water can better react with vehicle exhaust particles, so that the crystallization amount in an SCR system is reduced, the service life of the SCR system is prolonged, and the descaling period of the SCR system is prolonged to 5 kilometers from 3 kilometers of the travel of the existing diesel vehicle; on the other hand, the vehicle urea solution has better reaction activity, can improve the reaction fusion speed to a certain extent, and reduces the generation of intermediate products.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1, according to 100 parts of total weight, 32 parts of high-purity urea, 9 parts of cyclohexylamine, 9 parts of triethanolamine and 38 parts of small molecular group water as the rest are poured into a reaction kettle in sequence, and stirred and reacted at 75 ℃ for 4 hours to prepare a mixed raw material liquid;
then adding 9 parts of DL-methylthio-butyric acid and 3 parts of auxiliary agent (wherein 1.8 parts of alkyl glucoside and 1.2 parts of soot catalytic material) into the mixed raw material liquid, and continuously stirring and reacting in a reaction kettle at the reaction temperature of 50 ℃ for 3 hours to obtain a vehicle urea solution crude product with high conversion rate;
and finally, filtering and purifying the obtained crude product of the vehicle urea solution with the high conversion rate by using an ultrafiltration membrane with the membrane pore size of 0.6-0.8 mu m to obtain the vehicle urea solution with the high conversion rate.
The determination shows that the condensed appearance of the automobile urea solution with high conversion rate is clear and transparent, and the emission of NOx, CO, NMHC and PM meets the emission standard requirement of the national VI under the working conditions of ESC and ETC.
The emission of NOx of the automobile exhaust treated by the automobile urea solution is less than 1.0 g/(kw.h) -1.
The scale formation rate of the vehicle urea solution is 20% measured after the vehicle urea solution is used in an SCR system for ten days.
Example 2, according to 100 parts of the total weight, 33 parts of high-purity urea, 8% of cyclohexylamine, 7% of triethanolamine and 40 parts of small molecular group water are poured into a reaction kettle in sequence, and after stirring and reacting for 4 hours at 70 ℃, a mixed raw material liquid is prepared;
then 9 parts of DL-methylthio butanamic acid (DL-methionine) and 3 parts of auxiliary agent (1.2 parts of alkyl glucoside and 1.2 parts of soot catalytic material) are added into the mixed raw material liquid to continue to be stirred and react in a reaction kettle at the reaction temperature of 50 ℃ for 3 hours to obtain a vehicle urea solution crude product with high conversion rate;
and finally, filtering and purifying the obtained crude product of the vehicle urea solution with the high conversion rate by using an ultrafiltration membrane with the membrane pore size of 0.6-0.8 mu m to obtain the vehicle urea solution with the high conversion rate.
Through determination, the high-conversion-rate automobile urea solution is clear and transparent in condensed appearance, and NOx, CO, NMHC and PM emission meet the requirements of national VI emission standards under the working conditions of ESC and ETC.
The automobile exhaust treated by the automobile urea solution has the NOx emission less than 2.0 g/(kw.h) -1.
The scale formation rate of the vehicle urea solution is 25% after the vehicle urea solution is used in an SCR system for ten days.
Example 3, according to 100 parts of the total amount, 33 parts of high-purity urea, 9% of cyclohexylamine, 8% of triethanolamine and 50 parts of small molecular group water are poured into a reaction kettle in sequence, and after stirring and reacting for 6 hours at 60 ℃, a mixed raw material solution is prepared;
then adding 7 parts of DL-methylthiobutanic acid (DL-methionine) and 3 parts of auxiliary agent (1.8 parts of alkyl glucoside and 1.2 parts of soot catalytic material) into the mixed raw material liquid, and continuously stirring and reacting in a reaction kettle at the reaction temperature of 50 ℃ for 3 hours to obtain a vehicle urea solution crude product with high conversion rate;
and finally, filtering and purifying the crude product of the high-conversion-rate automobile urea solution by using an ultrafiltration membrane with a membrane pore size of 0.6-0.8 mu m to obtain the high-conversion-rate automobile urea solution.
The determination shows that the condensed appearance of the automobile urea solution with high conversion rate is clear and transparent, and the emission of NOx, CO, NMHC and PM meets the emission standard requirement of the national VI under the working conditions of ESC and ETC.
The emission of NOx of the automobile exhaust treated by the automobile urea solution is less than 2.0 g/(kw.h) -1.
The scale formation rate of the vehicle urea solution is 30% measured after the vehicle urea solution is used in an SCR system for ten days.
Example 4, according to 100 parts of the total amount, 34 parts of high-purity urea, 5% of cyclohexylamine, 5% of triethanolamine and 47 parts of small molecular group water are sequentially poured into a reaction kettle, and stirred and reacted at 60 ℃ for 6 hours to prepare a mixed raw material solution;
then adding 5 parts of DL-methylthiobutanic acid (DL-methionine) and 2 parts of auxiliary agent (0.9 part of alkyl glucoside and 1.1 part of soot catalytic material) into the mixed raw material liquid, and continuously stirring and reacting in a reaction kettle at the reaction temperature of 50 ℃ for 3 hours to obtain a vehicle urea solution crude product with high conversion rate;
and finally, filtering and purifying the obtained crude product of the vehicle urea solution with the high conversion rate by using an ultrafiltration membrane with the membrane pore size of 0.6-0.8 mu m to obtain the vehicle urea solution with the high conversion rate.
The determination shows that the condensed appearance of the automobile urea solution with high conversion rate is clear and transparent, and the emission of NOx, CO, NMHC and PM meets the emission standard requirement of the national VI under the working conditions of ESC and ETC.
The emission of NOx of the automobile exhaust treated by the automobile urea solution is less than 2.0 g/(kw.h) -1.
The scale formation rate of the vehicle urea solution is 35% measured after the vehicle urea solution is used in an SCR system for ten days.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (9)
1. The high-conversion-rate automobile urea solution is characterized by comprising the following components in parts by weight: 32-36% of high-purity urea, 1-9% of cyclohexylamine, 1-9% of triethanolamine, 4-11% of DL-methylthiobutanamic acid, 1-5% of an auxiliary agent and the balance of small molecular group water.
2. The high conversion vehicular urea solution according to claim 1, comprising the following components in percentage by weight: the paint comprises the following components in percentage by weight: 32% of high-purity urea, 9% of cyclohexylamine, 9% of triethanolamine, 9% of DL-methylthiobutanamic acid, 3% of an auxiliary agent and 38% of small molecular group water.
3. The urea solution for vehicles with high conversion rate as claimed in claim 1, wherein the half-value of the magnetic resonance of the water molecular group of the small molecular group water is 50 Hz, and the redox potential is between minus 150 and minus 500.
4. The vehicular urea solution with high conversion rate as claimed in claim 1, wherein the auxiliary agent is a mixture of alkyl glucoside and soot catalytic material.
5. The high-conversion-rate vehicular urea solution according to claim 4, wherein the weight ratio of the alkyl glucoside to the soot catalytic material is 0.9-1.8: 0.7 to 1.2.
6. A method for preparing a high conversion rate vehicular urea solution according to any one of claims 1 to 5, comprising the steps of:
(1) the preparation process of the micromolecular water comprises the following steps: the water tank is provided with core materials, the core materials comprise tourmaline, medical stone and muyu stone, ultrapure water passes through the water tank to form small molecular group water,
(2) weighing the components in parts by weight; pouring high-purity urea, glycerol, cyclohexylamine and small molecular group water into a stirring kettle in sequence for reaction to prepare mixed raw material liquid;
(3) adding DL-methylthio butyric acid and an auxiliary agent into the mixed raw material liquid, and continuously reacting in a reaction kettle to obtain a vehicle urea solution crude product with high conversion rate;
(4) and (3) filtering and purifying the crude product of the high-conversion-rate automobile urea solution to obtain the high-conversion-rate automobile urea solution.
7. The method as claimed in claim 6, wherein the reaction conditions in the water tank in step (1) are as follows: the temperature is 25-35 ℃, and the time is 3-5 h.
8. The method for preparing a high-conversion vehicular urea solution as claimed in claim 6, wherein the reaction conditions in the reaction kettle in the step (2) are as follows: the temperature is 60-80 ℃.
9. The method for preparing the vehicular urea solution with high conversion rate according to claim 6, wherein the step (3) is carried out by using an ultrafiltration membrane with a membrane pore size of 0.3-0.8 μm.
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| CN112316723A (en) * | 2020-11-13 | 2021-02-05 | 河南弘康环保科技有限公司 | Automobile urea solution for efficiently solving crystallization blockage |
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2022
- 2022-05-23 CN CN202210561519.1A patent/CN115006991A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH0768132A (en) * | 1994-06-17 | 1995-03-14 | Chiyoda Corp | Desulfurizing and denitrifying method |
| JPH10180036A (en) * | 1996-12-27 | 1998-07-07 | Hitachi Ltd | Purifying method of nitrogen oxide-containing gas and device therefor |
| US20040115110A1 (en) * | 2001-11-06 | 2004-06-17 | Wolfgang Ripper | Method and device for reducing nitrogen oxides present in exhaust gas |
| US20130224090A1 (en) * | 2009-11-19 | 2013-08-29 | Sk Innovation Co., Ltd. | Catalyst for selective oxidation of nh3 to n2 and method for preparing the same |
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| CN112316723A (en) * | 2020-11-13 | 2021-02-05 | 河南弘康环保科技有限公司 | Automobile urea solution for efficiently solving crystallization blockage |
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