Sectional type ammonia generating device for discomposing solid urea

A solid urea, segmented technology, applied in the direction of silencer, exhaust device, separation method, etc., can solve the problems of nitrate deposition, easy freezing, energy consumption, etc.

Inactive Publication Date: 2012-08-15
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] However, urea aqueous solution is easy to freeze and difficult to store at low temperature; and during the pyrolysis process of urea aqueous solution, most of the energy will be consumed in order to evaporate the water in urea
At the same time, urea will form deposits during the decomposition process and deposit on the surface of the SCR catalyst, which will easily deactivate the catalyst
Catalysis B: The research content in Environmental70 (2007) 91-99 shows that the isocyanic acid hydrolysis catalyst encounters NO in the tail gas X When nitrate is deposited on the surface of the catalyst, the hydrolysis catalyst will be deactivated

Method used

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  • Sectional type ammonia generating device for discomposing solid urea
  • Sectional type ammonia generating device for discomposing solid urea
  • Sectional type ammonia generating device for discomposing solid urea

Examples

Experimental program
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Effect test

Embodiment 1

[0048] figure 2 This shows a specific embodiment of the device of the present invention. In this solution, the ammonia production device from urea decomposition of the present invention is installed in front of the exhaust gas treatment device in the exhaust gas discharge pipeline.

[0049] In this solution, when the exhaust gas of the car starts to be discharged, the ECU starts the heating program of the electric heating device through the command conduction lines 401 and 701, so that the electric heating devices 4 and 7 start heating. The device 11 in the figure represents a water vapor flow meter, which can control the gas flow entering the ammonia reaction tank 2 through the water vapor conveying pipe 9. The flow rate of water vapor passing through the water vapor flow meter 11 is controlled by the ECU. The water vapor flow meter 11 Transmit the sensed water vapor flow value to the ECU through the command transmission wire 111, and then the ECU transmits the feedback signal ...

Embodiment 2

[0051] 4.94g(Al(NO 3 ) 3 9H 2 O is dissolved in 20g of distilled water to form solution A;

[0052] Mix 5.712g of anhydrous ethanol solution, 3ml of distilled water, and 0.2ml of 65% nitric acid with a mass concentration of nitric acid, and then weigh 6.7695g of ethyl orthosilicate solution, slowly adding 4ml of ethyl orthosilicate every 1 minute Pour into the mixed solution of this step and stir vigorously at a speed of, and finally form a transparent and clear solution B;

[0053] Pour liquid B into solution A at a speed of 2ml / min, stir vigorously for 0.5 hours and age for 12 hours to finally form a glass coating sol solution.

[0054] Take 5 pieces of nickel-chromium-iron metal wire mesh, each piece of metal wire mesh is a square with a side length of 5 cm, and the metal wire mesh has an aperture of 300 meshes. Perform the pretreatment described in the content of the invention, and then immerse the metal wire mesh carrier into the previous preparation Soak in the coating sol sol...

Embodiment 3

[0060] Add 14g Al(NO 3 ) 3 9H 2 O is dissolved in 40g of distilled water to form solution A;

[0061] Mix 5.712g of anhydrous ethanol solution, 3ml of distilled water, and 0.2ml of 65% nitric acid with a mass concentration of nitric acid, then weigh 6.6g of ethyl orthosilicate solution, slowly reduce the amount of ethyl orthosilicate to 4ml every 1 minute Pour into the mixed solution of this step and stir vigorously at a speed of, and finally form a transparent and clear solution B;

[0062] Pour liquid B into solution A at a speed of 2ml / min, continuously and vigorously stir for 0.5 hours, aging for 12 hours, and finally form a ratio of catalyst sol solution.

[0063] Take 5 nickel-chromium-iron metal honeycomb supports, each metal support is a cylinder with a diameter of 5cm and a height of 7cm. The metal supports are subjected to the pretreatment described above, and then the metal honeycomb supports are immersed in the above catalyst solution, each time 10 minutes, each coating ...

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Abstract

The invention belongs to the field of cleaning of the tail gas of a diesel engine, and particularly relates to a sectional type ammonia generating device for discomposing solid urea, wherein the device can be used for treating the tail gas of a motor vehicle. The device consists of an ammonia reaction tank, an urea pyrolysis catalysis device and an isocyanic acid hydrolysis catalysis device, which are sequentially arranged in the ammonia reaction tank according to an airflow direction; the front end of the ammonia reaction tank is provided with an urea inlet, the back end of the ammonia reaction tank is provided with an ammonia outlet, and a steam transporting conduit is arranged nearby the urea inlet; the urea pyrolysis catalysis device is formed by a multi-layer wire mesh carrier which is coated with a glass coating layer SiO2-Al2O3 and loaded with a urea pyrolysis catalyst Pt, Ag or Pd; and the isocyanic acid hydrolysis catalysis device is formed by a metal honeycomb carrier coated with the isocyanic acid hydrolysis catalyst SiO2-Al2O3. Due to the urea pyrolysis catalyst and the isocyanic acid hydrolysis catalyst, the device is used for catalyzing each stage of ammonia generation by ammonia, so that the reaction temperature can be reduced, the reaction can be accelerated, and the energy can be saved.

Description

Technical field [0001] The invention belongs to the field of diesel engine tail gas purification, and specifically relates to a segmented solid urea decomposition ammonia production device, which can be applied to motor vehicle tail gas treatment. technical background [0002] NO in pollutants emitted from motor vehicle exhaust X Global NO X 20% of the total pollution. In order to eliminate these pollution and meet increasingly stringent exhaust emission standards, diesel vehicle exhaust aftertreatment technology has become a technology that people need to develop urgently. At present, ammonia selective catalytic reduction technology (SCR denitrification technology) is considered to be the most effective method for removing NO from motor vehicle exhaust X Technology. SCR denitration technology uses NH under the action of a catalyst under oxygen-rich conditions 3 As a reducing agent, and NO in exhaust gas X The following redox reactions occur: [0003] 4NH 3 +4NO+O 2 = 4N 2 +6H 2 O...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F01N3/28C01C1/02B01D53/94B01D53/56
CPCY02A50/20
Inventor 韩炜李骏韩旭张贺张克金周亮张苡铭韩建曹雅彬王磊
Owner JILIN UNIV
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