Method for preparing vehicle urea solution

A technology of urea and urea aqueous solution for vehicles is applied in the field of chemical technology, which can solve the problems of high steam consumption and low urea purity, and achieve the effect of reducing production links and saving costs.

Inactive Publication Date: 2015-01-21
HENAN HONGKANG ENVIRONMENTAL PROTECTION TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the past, the common reports used urea granules as the raw material for purification. However, the urea granulation process consumes a lot of steam and requires a certain amount of formaldehyde. not tall

Method used

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  • Method for preparing vehicle urea solution

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Experimental program
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Effect test

Embodiment 1

[0016] (1) Lift the industrial desalted water into the reverse osmosis device with a high-pressure pump, the water output from the reverse osmosis device enters the intermediate water tank, the intermediate water tank passes through a microporous filter to the pure water tank, and the effluent from the pure water tank is sterilized after being treated by an EDI electrodeionization device High-purity water, the conductivity of high-purity water is less than 0.06μs / cm, and the resistivity is 16.8MΩ.cm25℃;

[0017] (2) Remove ammonia and CO by flash evaporation during urea production 2 The final temperature is 90.6°C, and the high-temperature urea solution with a concentration of 74.9% is fully mixed with the high-purity water prepared in step (1) to prepare an aqueous urea solution with a temperature of 69.2°C and a concentration of 48.6wt%;

[0018] (3) The aqueous urea solution in step (2) was cooled to 25°C, filtered to obtain crystalline urea, and the crystalline urea was mi...

Embodiment 2

[0021] (1) Lift the industrial desalted water into the reverse osmosis device with a high-pressure pump, the water output from the reverse osmosis device enters the intermediate water tank, the intermediate water tank passes through a microporous filter to the pure water tank, and the effluent from the pure water tank is sterilized after being treated by an EDI electrodeionization device High-purity water, the conductivity of high-purity water is less than 0.06μs / cm, and the resistivity is 17.7MΩ.cm25℃;

[0022] (2) Remove ammonia and CO by flash evaporation during urea production 2 The final temperature is 85.0°C, and the high-temperature urea solution with a concentration of 84% is fully mixed with the high-purity water prepared in step (1) to prepare an aqueous urea solution with a temperature of 71.8°C and a concentration of 53.6wt%;

[0023] (3) The aqueous urea solution in step (2) was cooled to 25°C, filtered to obtain crystallized urea, and the crystallized urea was mi...

Embodiment 3

[0026] (1) Lift the industrial desalted water into the reverse osmosis device with a high-pressure pump, the water output from the reverse osmosis device enters the intermediate water tank, the intermediate water tank passes through a microporous filter to the pure water tank, and the effluent from the pure water tank is sterilized after being treated by an EDI electrodeionization device High-purity water, the conductivity of high-purity water is less than 0.06μs / cm, and the resistivity is 18.0MΩ.cm25℃;

[0027] (2) Remove ammonia and CO by flash evaporation during urea production 2 The final temperature is 92.4°C, and the high-temperature urea solution with a concentration of 80.3% is fully mixed with the high-purity water prepared in step (1) to prepare an aqueous urea solution with a temperature of 70.3°C and a concentration of 50.7wt%;

[0028] (3) Cool the aqueous urea solution in step (2) to 20°C, filter to obtain crystalline urea, and mix the crystalline urea with high-...

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Abstract

The invention discloses a method for preparing a vehicle urea solution. The method comprises the following steps: treating industrial desalted water by a reverse osmosis device, a microporous filter and an EDI electric deionizing device and then sterilizing to obtain high purity water, wherein the resistivity of the high purity water is equal to or greater than 16 Momega.cm at 25 DEG C; mixing the high purity water with a high temperature urea solution which is subjected to ammonia and CO2 removal by virtue of flash evaporation during production of urea to prepare a urea aqueous solution with the concentration of 48-55wt% and the temperature of 68-72 DEG C; then cooling to 18-25 DEG C, filtering to obtain crystallized urea, mixing the crystallized urea and the high purity water to prepare another urea aqueous solution with the concentration of 31.8-33.2wt%; finally filtering by a filter film with the aperture of 0.2-0.5 micron to obtain the final vehicle urea solution. According to the method, the vehicle urea solution is directly produced without an external heating source, the contents of biuret, metal ions, insoluble substances and the like are relatively low, the method is especially suitable for directly producing vehicle urea in a urea production factory, and the cost during production is reduced.

Description

technical field [0001] The invention belongs to the technical field of chemical technology, and in particular relates to a preparation method of urea solution for vehicles. Background technique [0002] CO, CO of diesel vehicles 2 Emissions are lower than gasoline vehicles, while NO emissions X (nitrogen oxides) and PM (particulate matter) are much higher than gasoline vehicles, SCR (Selective Catalytic Reduction) selective catalytic reduction technology uses reducing agent urea solution for selective catalytic reduction of nitrogen oxides, reducing NO X emission, so as to meet the National IV emission regulations for PM and NO X limits. The fuel economy of the engine with SCR technology is good, the engine changes are small, the requirements for fuel and engine oil are low, and it has advantages in the continuity of technology upgrades. It is a must for diesel vehicles equipped with SCR system. [0003] The urea solution for vehicles is strictly controlled on impuritie...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/94B01D53/56
Inventor 汤广斌李丰登孙长城桑书梅李伟萍邓欢韩娟
Owner HENAN HONGKANG ENVIRONMENTAL PROTECTION TECH
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