Ammonia-removing and alkali-reducing device for urea solution for vehicle

Abstract

The utility model provides a vehicle urea solution ammonia removal and alkali reduction device which comprises a vehicle urea solution storage tank and a spraying device connected with the upper part of a treatment tower through a circulating pump pipeline, and the bottom of the treatment tower is connected with the vehicle urea solution storage tank through a U-shaped bent pipe; the top of the treatment tower is connected with a tail gas treatment device, and the lower part of the treatment tower is connected with an inert gas pipeline. The tail gas treatment device comprises a washing tower connected with the treatment tower; a spraying device is arranged at the upper part of the washing tower and is connected with a desalted water pipeline; the lower part of the washing tower is connected with a dilute ammonia water tank; and the top of the washing tower is connected with an emptying cylinder. According to the utility model, the ammonia content in the urea solution for vehicles is reduced, the alkalinity of the solution is controlled, and the production and use environment of the urea solution for vehicles is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle urea solution treatment, and particularly relates to a device for removing ammonia and reducing alkalinity of vehicle urea solution. Background Technique

[0002] Vehicle urea solution refers to an aqueous urea solution with a urea concentration of about 32.5% and ultrapure water as the solvent, which is widely used in the treatment of diesel vehicle exhaust. The product execution standard is GB 29518-2013 "Diesel Engine Nitrogen Oxide Reducing Agent Urea Aqueous Solution (AUS32)", and the alkalinity index is not more than 0.2% (calculated as NH3). There are two main production processes for vehicle urea solution: the method of dissolving urea crystals, recrystallizing and purifying for preparation, and the method of directly preparing urea solution. Among them, for the method of directly preparing urea solution, about 70% of the flash urea solution is diluted with ultrapure water. For urea manufacturers, it is simple, easy to operate, low in cost, and easy to scale up production, which is the optimal solution. However, during the preparation, since the ammonia in the raw material solution is not treated by the evaporation system, under abnormal conditions such as high flash pressure and low urine concentration, the ammonia content in the product solution will exceed 0.2%, and the alkalinity is unqualified; at the same time, the high ammonia content will also affect the environment due to the volatilization of irritating gases. Content of the Utility Model

[0003] The utility model provides a device for removing ammonia and reducing alkalinity of vehicle urea solution, which reduces the ammonia content in the vehicle urea solution, controls the solution alkalinity, and improves the production and use environment of the vehicle urea solution.

[0004] The specific scheme is as follows:

[0005] A device for removing ammonia and reducing alkalinity of vehicle urea solution includes a vehicle urea solution storage tank, which is connected to a spray device at the upper part of a treatment tower through a circulation pump pipeline, and the bottom of the treatment tower is connected to the vehicle urea solution storage tank through a U-shaped bend pipe; a packing layer A is arranged in the middle of the treatment tower, the top is connected to a tail gas treatment device, and the lower part is connected to an inert gas pipeline.

[0006] The tail gas treatment device includes a scrubbing tower connected to the treatment tower; a packing layer B is arranged in the middle of the scrubbing tower, a spray device is arranged at the upper part and connected to a desalinated water pipeline, the lower part is connected to a dilute ammonia water tank, and the top is connected to a vent stack.

[0007] A stirrer is arranged in the vehicle urea solution storage tank.

[0008] A flowmeter and a regulating valve are arranged on the inert gas pipeline.

[0009] A flowmeter and a regulating valve are arranged on the desalinated water pipeline.

[0010] The urea aqueous solution for vehicle use of the present utility model is prepared and stored in a urea aqueous solution storage tank for vehicle use. A stirrer is installed in the urea aqueous solution storage tank for vehicle use to uniformly mix the solution; the urea aqueous solution for vehicle use is sent to a spray device at the upper part of a treatment tower through a circulation pump. After passing through a packing layer A, stripping of ammonia is carried out under normal pressure with an inert gas (usually nitrogen, and air can also be used when the ammonia concentration is low) to reduce the ammonia content in the urea aqueous solution for vehicle use; the flow rate of the inert gas is controlled by a flowmeter and a regulating valve on an inert gas pipeline; the urea aqueous solution for vehicle use after stripping of ammonia returns to the urea aqueous solution storage tank for vehicle use, and a U-shaped elbow at the bottom of the treatment tower can prevent the inert gas from flowing into; the inert gas containing ammonia after stripping enters a scrubbing tower. A packing layer B is installed in the scrubbing tower, and demineralized water is sprayed into the scrubbing tower through a spray device to absorb the ammonia in the inert gas containing ammonia. The amount of demineralized water is controlled by a flowmeter and a regulating valve on a demineralized water pipeline; the tail gas after scrubbing is discharged into the atmosphere through a vent stack, and the diluted ammonia water after scrubbing is recovered into a diluted ammonia water tank.

[0011] The present utility model adopts an inert gas stripping method to strip the ammonia in the urea aqueous solution for vehicle use, thereby reducing the ammonia content in the solution and making the alkalinity reach the standard; continuous solution circulation stripping can reduce the ammonia content to below 0.1%. The solution after stripping of ammonia returns from the top of the urea aqueous solution storage tank for vehicle use. Through the combined action of downward flow and stirring, the overall alkalinity index of the solution is made uniform. The diluted ammonia water after being absorbed by the tail gas treatment device is recovered into a diluted ammonia water tank, realizing environmental protection and energy consumption reduction. Description of the Drawings

[0012] Figure 1 . Structural schematic diagram of the present utility model. Detailed Embodiments

[0013] As Figure 1 shown, an ammonia removal and alkalinity reduction device for urea aqueous solution for vehicle use includes a urea aqueous solution storage tank 1 for vehicle use, which is connected to a spray device 4 at the upper part of a treatment tower 3 through a pipeline of a circulation pump 2. The bottom of the treatment tower 3 is connected to the urea aqueous solution storage tank 1 for vehicle use through a U-shaped elbow 5; a packing layer A6 is arranged in the middle of the treatment tower 3, the top is connected to a tail gas treatment device, and the lower part is connected to an inert gas pipeline 7.

[0014] The tail gas treatment device includes a scrubbing tower 8 connected to the treatment tower 3; a packing layer B9 is arranged in the middle of the scrubbing tower 8, a spray device 4 is arranged at the upper part and is connected to a demineralized water pipeline 10, the lower part is connected to a diluted ammonia water tank 11, and the top is connected to a vent stack 12.

[0015] A stirrer 13 is arranged in the urea aqueous solution storage tank 1 for vehicle use.

[0016] A flowmeter 14 and a regulating valve 15 are arranged on the inert gas pipeline 7.

[0017] A flowmeter 14 and a regulating valve 15 are arranged on the demineralized water pipeline 10.

[0018] The urea aqueous solution for vehicle use of the present utility model is prepared and stored in the urea aqueous solution storage tank 1 of the vehicle. A stirrer 13 is installed in the urea aqueous solution storage tank 1 to uniformly mix the solution. The urea aqueous solution for vehicle use is sent to the spraying device 4 at the upper part of the treatment tower 3 through the circulation pump 2, and passes through the packing layer A6. Under normal pressure, stripping of ammonia is carried out with an inert gas (usually nitrogen, and air can also be used when the ammonia concentration is low) to reduce the ammonia content in the urea aqueous solution for vehicle use. The flow rate of the inert gas is controlled by the flowmeter 14 and the regulating valve 15 on the inert gas pipeline 7. The urea aqueous solution for vehicle use after stripping of ammonia returns to the urea aqueous solution storage tank 1. The U-shaped elbow 5 at the bottom of the treatment tower 3 can prevent the inert gas from flowing into it. The inert gas containing ammonia after stripping enters the washing tower 8. The washing tower 8 is installed with a packing layer B9. Desalted water is sprayed into the washing tower 8 through the spraying device 4 to absorb the ammonia in the inert gas containing ammonia. The amount of desalted water is controlled by the flowmeter 14 and the regulating valve 15 on the desalted water pipeline 10. The tail gas after washing is discharged into the atmosphere through the vent stack 12, and the dilute ammonia water after washing is recovered into the dilute ammonia water tank 11.

[0019] The present utility model adopts the inert gas stripping method to strip the ammonia in the urea aqueous solution for vehicle use, thereby reducing the ammonia content in the solution and making the alkalinity meet the standard. By continuously carrying out the solution circulation stripping, the ammonia content can be reduced to less than 0.1%. The solution after stripping of ammonia returns from the top of the urea aqueous solution storage tank 1. Through the mixing action of downward flow and stirring, the overall alkalinity index of the solution is made uniform. The dilute ammonia water after being absorbed by the tail gas treatment device is recovered into the dilute ammonia water tank 11, achieving environmental protection and energy consumption reduction.

[0020] The above are only some preferred embodiments of the present utility model, and do not impose any form of limitation on the present utility model. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present utility model without departing from the content of the technical solution of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. An ammonia removal and alkali reduction device for vehicle urea solution, characterized in that, It includes a vehicle urea solution storage tank, which is connected to a spraying device at the upper part of a treatment tower through a circulating pump pipeline. The bottom of the treatment tower is connected to the vehicle urea solution storage tank through a U-shaped elbow pipe. A packing layer A is arranged in the middle of the treatment tower, the top is connected to an exhaust gas treatment device, and the lower part is connected to an inert gas pipeline.

2. The ammonia removal and alkali reduction device for vehicle urea solution according to claim 1, wherein The exhaust gas treatment device includes a scrubbing tower connected to the treatment tower. A packing layer B is arranged in the middle of the scrubbing tower, a spraying device is arranged at the upper part and connected to a desalinated water pipeline, the lower part is connected to a dilute ammonia water tank, and the top is connected to a vent stack.

3. The ammonia removal and alkalinity reduction device for vehicle urea solution according to claim 1, characterized in that, A stirrer is arranged in the vehicle urea solution storage tank.

4. The ammonia removal and alkalinity reduction device for vehicle urea solution according to claim 1, characterized in that, A flowmeter and a regulating valve are arranged on the inert gas pipeline.

5. The ammonia removal and alkalinity reduction device for vehicle urea solution according to claim 2, wherein, A flowmeter and a regulating valve are arranged on the desalinated water pipeline.

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