Value-added urea production device

Abstract

The utility model provides a value-added urea production device. The value-added urea production device comprises a molten urea evaporation system, a three-way switching valve, a static mixer and a granulation device which are connected in sequence, the static mixer is connected with an additive adding device; the additive adding device comprises an additive barrel, a suction pump, a distribution tank, a filter and a head tank which are connected in sequence; the distribution tank is connected with a compressed air inlet pipeline and an exhaust pipeline, and is also connected with a desalted water adding device. According to the utility model, the additive injection point is positioned in the static mixer behind the three-way switching valve, so that the additive and the molten urea are mixed and then immediately enter the granulating device, and cannot be returned to a molten urea system under abnormal working conditions, and the corrosion aggravation of equipment caused by the fact that chloride ions enter an evaporation system and a front system is avoided; and meanwhile, product switching is more efficient, additives are fully utilized, transition products are reduced, and the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to a production technology of value-added urea, in particular to a value-added urea production device capable of preventing equipment corrosion. Background Art

[0002] Value-added urea refers to urea products that have synergists or other nutrients added to them. In urea production, the urea solution synthesized by the high-pressure system is decompressed and evaporated to obtain 99.7% molten urea, which is then pumped to the granulation tower to form solid urea granules. The value-added urea production device usually makes the additive into a solution, injects it into the evaporation system in urea production with a metering pump, and after evaporation, mixing and concentration, granulation is performed to obtain the value-added urea product.

[0003] The current problems of value-added urea production equipment are as follows: (1) Equipment corrosion: Some additives are acidic and contain a small amount of impurities, especially chloride ions, which can reach hundreds of ppm; value-added urea usually adds pigments of different colors to distinguish the appearance, and there are also chloride ions in the pigments, and their content is at the level of 1%; the total chloride ion content in the solution can reach about 1000 ppm. The production equipment is usually made of austenitic stainless steel above 304L, and the high-pressure equipment uses urea-grade stainless steel above 316L. After the additive solution is added to the evaporation system, the chloride ions it contains will cause the corrosion of the evaporation system equipment to intensify at high temperatures, and the chloride ions may be entrained into other high-pressure or low-pressure systems during the evaporation process, which may cause local chloride ion enrichment in the high-pressure system equipment, forming intergranular corrosion, causing perforation and leakage of the high-pressure system equipment, bringing major safety and environmental risks. (2) Since the amount of additives injected is small, usually only a few kilograms are added to 1 ton of urea. The current method of injecting additives is to use a diaphragm pump for delivery, which has a pulse phenomenon, causing fluctuations in the additive flow rate, affecting the stability of the injection amount and the uniformity of the additive content in the product. In order to ensure the additive content of the product, the injection amount needs to be appropriately increased, resulting in an increase in dosage. Moreover, the diaphragm pump is a rotating device. In the event of a fault, the pump will drop, jump, or be reversed for maintenance, which will also affect the injection amount and continuity of the additive, resulting in defective products with substandard content and uneven color, increasing production costs. Utility Model Content

[0004] In view of the above problems of the prior art, the utility model provides a value-added urea production device, in which the additive injection point is located in a static mixer after a three-way switching valve, so that the additive and molten urea are mixed and immediately enter a granulation device, and will not flow back to the molten urea system under abnormal conditions, thereby avoiding chloride ions from entering an evaporation system and a front system to aggravate equipment corrosion and improving production efficiency.

[0005] The technical solution of this utility model is as follows:

[0006] A value-added urea production device comprises a molten urea evaporation system, a three-way switching valve, a static mixer, and a granulating device which are connected in sequence; the static mixer is connected to an additive adding device;

[0007] The additive adding device comprises an additive barrel, a suction pump, a distribution tank, a filter, and a high-level tank which are connected in sequence; the distribution tank is connected to a compressed air intake pipeline and an exhaust pipeline; the high-level tank is connected to a static mixer via a remote shut-off valve;

[0008] The distribution tank is also connected to a desalted water adding device.

[0009] The distribution tank and the high-level tank are both provided with liquid level gauges.

[0010] A flow regulating valve and a flow meter are arranged at the rear section of the high-level tank.

[0011] The bottoms of the distribution trough and the high-level trough are conical or spherical.

[0012] The beneficial effects of the utility model are:

[0013] 1. The additive injection point is located in the static mixer behind the three-way switching valve, so that the additive and molten urea are mixed and immediately enter the granulation device. Under abnormal conditions, it will not flow back to the molten urea system, thus avoiding chloride ions entering the evaporation system and the front system to aggravate equipment corrosion.

[0014] 2. Send the additive solution into the high-level tank and add it to the static mixer using the potential difference. With the flow regulating valve, the flow can be accurately controlled with small flow fluctuations, which improves the uniformity of the additive content in the product and avoids the waste of raw materials and fluctuations in urea product indicators caused by large fluctuations and the need to increase the surplus flow.

[0015] 3. Compressed gas is used for pressurized transportation from the distribution tank to the high-level tank. There is no rotating equipment, low failure rate and reliable operation.

[0016] 4. The distribution trough and high-level trough are designed as non-planar bottom plates such as cones or spherical shapes. The solution extraction point is at the lowest position of the bottom plate, which improves the utilization rate of additives and avoids the waste of raw materials.

[0017] 5. Filters are installed on the pipeline to prevent crystallization and solid impurities from entering to ensure the quality of value-added urea. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 .Schematic diagram of the structure of the utility model. DETAILED DESCRIPTION

[0019] like Figure 1As shown, a value-added urea production device comprises a molten urea evaporation system 1, a three-way switching valve 2, a static mixer 3, and a granulating device 4 which are connected in sequence; the static mixer 3 is connected to an additive adding device;

[0020] The additive adding device comprises an additive barrel 5, a suction pump 6, a distribution tank 7, a filter 8, and a high-level tank 9 which are connected in sequence; the distribution tank 7 is connected to a compressed air intake pipeline 10 and an exhaust pipeline 11, and is also connected to a desalted water adding device 12; a flow regulating valve 13 and a flow meter 14 are arranged at the rear section of the high-level tank 9, and then connected to a static mixer 3 via a remote shut-off valve 15; both the distribution tank 7 and the high-level tank 9 are provided with a liquid level meter 16, and the bottom is conical or spherical.

[0021] The utility model mixes an additive solution and a pigment in an additive barrel 5, pumps the mixture into a distribution tank 7 through a suction pump 6, adds a proper amount of desalted water through a desalted water adding device 12 for dilution, pressurizes the distribution tank 7 through a compressed air intake pipeline 10, and when the pressure reaches about 1MPa, opens the external valve at the bottom of the distribution tank 7, and fills the high-level tank 9 with liquid through a filter 8; opens a flow regulating valve 13 and a remote shut-off valve 15 at the rear section of the high-level tank 9, and injects a pigment-containing additive solution into a static mixer 3 with reference to the value of a flow meter 14, and uniformly mixes the additive solution with the molten urea from a molten urea evaporation system 1; and then granulates the solution through a granulating device 4 to obtain a value-added urea product.

[0022] The additive injection point of the utility model is located in the static mixer 3 after the three-way switching valve 2, so that the additive and the molten urea are mixed and immediately enter the granulation device 4, and will not flow back to the molten urea system under abnormal working conditions, thereby avoiding chloride ions from entering the evaporation system and the front system to cause aggravated equipment corrosion.

[0023] The additive solution is sent to the high-level tank 9, and added to the static mixer 3 by utilizing the potential difference. In combination with the flow regulating valve 13, the flow rate can be accurately controlled with small flow fluctuations, thereby improving the uniformity of the additive content in the product and avoiding the waste of raw materials and fluctuations in urea product indicators caused by large fluctuations and the need to increase the surplus flow.

[0024] Compressed gas is used to transport from the distribution tank 7 to the high-level tank 9. There is no rotating equipment, the failure rate is low, and the operation is reliable. When the operation is stopped, the valve of the exhaust pipe 11 can be opened to release the pressure.

[0025] The distribution trough 7 and the high-level trough 9 are designed as non-planar bottom plates such as cones or spheres, and the solution taking-out point is at the lowest position of the bottom plate, which improves the utilization rate of additives and avoids the waste of raw materials.

[0026] The above descriptions are only some of the preferred embodiments of the present invention and do not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A value-added urea production device, characterized in that: It includes a molten urea evaporation system, a three-way switching valve, a static mixer, and a granulating device which are connected in sequence; the static mixer is connected to an additive adding device; The additive adding device comprises an additive barrel, a suction pump, a distribution tank, a filter, and a high-level tank which are connected in sequence; the distribution tank is connected to a compressed air intake pipeline and an exhaust pipeline; and the high-level tank is connected to a static mixer via a remote cut-off valve.

2. The value-added urea production device according to claim 1, characterized in that: The distribution tank is also connected to a desalted water adding device.

3. The value-added urea production device according to claim 1, characterized in that: The distribution tank and the high-level tank are both provided with liquid level gauges.

4. The value-added urea production device according to claim 1, characterized in that: A flow regulating valve and a flow meter are arranged at the rear section of the high-level tank.

5. The value-added urea production device according to claim 1, characterized in that: The bottoms of the distribution trough and the high-level trough are conical or spherical.

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