Device for improving absorption effect of ammonia washing tower of triamine device
By combining a wastewater stripping tower with an ammonia scrubbing tower, using a mixture of purified wastewater and demineralized water as an absorbent, and improving gas-liquid contact efficiency through heat exchangers and small-diameter packing, the problems of high demineralized water consumption and poor ammonia absorption in melamine plants were solved, achieving efficient ammonia absorption and resource recovery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 新疆心连心能源化工有限公司
- Filing Date
- 2025-09-09
- Publication Date
- 2026-07-31
AI Technical Summary
The existing ammonia scrubbing towers in melamine plants have problems such as high consumption of demineralized water and poor ammonia absorption. Furthermore, incomplete absorption of ammonia leads to resource waste and environmental pollution.
By combining a wastewater stripping tower and an ammonia scrubbing tower, the purified wastewater and demineralized water are mixed as an absorbent, and the temperature of the absorbent is reduced by the first and second heat exchangers. Small-diameter Pall ring packing is used to improve the gas-liquid contact efficiency, and a spray device and temperature detector are added to control the absorption process, thereby improving the absorption effect of the ammonia scrubbing tower.
It significantly reduced the consumption of demineralized water, decreased the amount of cooling medium used, improved the ammonia absorption rate, reduced ammonia emissions, and achieved resource recovery and environmentally friendly treatment of ammonia.
Smart Images
Figure CN224573504U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of melamine equipment technology, and is a device for improving the absorption effect of the ammonia scrubbing tower in a melamine equipment. Background Technology
[0002] The main function of the ammonia scrubbing tower in a melamine plant is to absorb ammonia gas from ammonia-containing waste gas using an absorbent, thereby reducing ammonia pollution and achieving resource recovery. However, the current plant has the following drawbacks in actual operation: (1) The original process uses demineralized water as the absorbent. Although demineralized water has good absorption performance, its large-scale use will significantly increase the consumption of the equipment. Excessive use of demineralized water will lead to an increase in the load of subsequent water treatment and may even affect the normal operation of the equipment. High water consumption not only increases production costs, but also increases the difficulty and cost of wastewater treatment; (2) The air released from the top of the ammonia scrubbing tower in the original process contains a large amount of unabsorbed ammonia, resulting in serious waste of resources. The existing ammonia scrubbing tower has poor absorption effect, resulting in a large amount of ammonia being directly discharged into the atmosphere without effective absorption. This not only increases the ammonia consumption per unit of melamine products, but also increases production costs; (3) The absorbent used to absorb ammonia is at too high a temperature, resulting in unstable absorption. The absorption process of ammonia is an exothermic reaction. Increased temperature will significantly reduce the solubility of ammonia in the absorbent, thereby weakening the absorption effect. In the existing process, due to insufficient heat management of the system or low efficiency of cooling equipment, the temperature of the absorbent is high when it enters the ammonia scrubbing tower, which reduces the gas-liquid contact efficiency in the tower and makes it difficult to guarantee the ammonia absorption rate. This temperature fluctuation not only affects the stable operation of the ammonia scrubbing tower, but may also lead to excessive ammonia content in the gas emitted from the top of the tower, further aggravating ammonia waste and environmental pollution.
[0003] Therefore, the ammonia scrubbing tower in existing melamine plants suffers from problems such as high consumption of demineralized water and poor ammonia absorption efficiency. Summary of the Invention
[0004] This invention provides a device for improving the absorption effect of the ammonia scrubbing tower in a melamine plant, overcoming the shortcomings of the prior art. It can effectively solve the problems of high consumption of demineralized water and poor ammonia absorption effect in the existing ammonia scrubbing tower of the melamine plant.
[0005] The technical solution of this utility model is achieved through the following measures: A device for improving the absorption effect of an ammonia scrubbing tower in a melamine unit includes a wastewater stripping tower, a first heat exchanger, a second heat exchanger, and an ammonia scrubbing tower. The inlet of the wastewater stripping tower is fixedly connected to an ammonia-containing wastewater inlet pipeline, the top outlet of the wastewater stripping tower is fixedly connected to an ammonia gas outlet pipeline, the bottom outlet of the wastewater stripping tower is fixedly connected to the inlet of the first heat exchanger, the outlet of the first heat exchanger is fixedly connected to the inlet of the second heat exchanger, a demineralized water inlet pipeline is fixedly connected to the second treatment pipeline, a spray device is provided on the inner side of the upper part of the ammonia scrubbing tower, a third treatment pipeline is fixedly connected to the outlet of the second heat exchanger and the inlet of the spray device, the bottom inlet of the ammonia scrubbing tower is fixedly connected to an ammonia-containing waste gas inlet pipeline, and the top outlet of the ammonia scrubbing tower is fixedly connected to an venting pipeline.
[0006] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution: The first heat exchanger has a fixed connection between its cooling medium inlet and a raw water inlet pipeline, and a fixed connection between its cooling medium outlet and a raw water outlet pipeline. The second heat exchanger has a fixed connection between its cooling medium inlet and a cooling circulating water inlet pipeline, and a fixed connection between its cooling medium outlet and a cooling circulating water outlet pipeline.
[0007] The above-mentioned spraying device includes a liquid distribution plate and liquid distribution nozzles. The liquid distribution plate is provided with a liquid distribution chamber. The upper side of the liquid distribution plate is provided with a liquid inlet that can communicate with the liquid distribution chamber. A third processing pipeline is fixedly connected between the outlet of the second heat exchanger and the liquid inlet of the spraying device. Several liquid outlets are provided on the lower side of the liquid distribution chamber. A liquid distribution nozzle is fixedly installed on the lower side of the liquid distribution plate corresponding to each liquid outlet.
[0008] The ammonia scrubbing tower located below the spraying device is equipped with a first packing layer, a second packing layer, and a third packing layer. The packing in the first and second packing layers is Pall ring packing with a diameter of 0.625 inches, and the packing in the third packing layer is Pall ring packing with a diameter of 1 inch.
[0009] The aforementioned third treatment pipeline is equipped with a flow controller and a first temperature detector, the demineralized water inlet pipeline is equipped with a first electrically controlled valve, the first electrically controlled valve is interlocked with the flow controller, and the top of the ammonia scrubbing tower is equipped with a second temperature detector.
[0010] The aforementioned venting pipeline and the ammonia-containing waste gas inlet pipeline are fixedly connected by a waste gas circulation pipeline. An ammonia concentration detector is installed on the venting pipeline, and a second electrically controlled valve is installed on the waste gas circulation pipeline. The ammonia concentration detector and the second electrically controlled valve are interlocked.
[0011] This utility model has a reasonable and compact structure and is easy to use. It innovatively reuses the wastewater purified in the wastewater stripping tower and mixes it with demineralized water as an absorbent, reducing the consumption of demineralized water. It also adds a first heat exchanger and uses lower-temperature raw water as a cooling medium, which greatly reduces the amount of cooling circulating water used as the cooling medium for the second heat exchanger. In addition, by reducing the size of the packing material in the ammonia scrubbing tower, the absorption effect is improved. Attached Figure Description
[0012] Appendix Figure 1 This is a schematic diagram of the process flow of this utility model.
[0013] Appendix Figure 2 For the appendix Figure 1 A schematic diagram of the structure of the spray device.
[0014] Appendix Figure 1 The codes in the diagram are as follows: 1 for wastewater stripping tower, 2 for first heat exchanger, 3 for second heat exchanger, 4 for ammonia scrubbing tower, 5 for ammonia-containing wastewater inlet pipeline, 6 for ammonia gas outlet pipeline, 7 for first treatment pipeline, 8 for second treatment pipeline, 9 for demineralized water inlet pipeline, 10 for third treatment pipeline, 11 for ammonia-containing waste gas inlet pipeline, 12 for venting pipeline, 13 for raw water inlet pipeline, 14 for raw water outlet pipeline, 15 for cooling circulating water inlet pipeline, 16 for cooling circulating water outlet pipeline, 17 for liquid distribution plate, 18 for liquid distribution nozzle, 19 for first packing layer, 20 for second packing layer, 21 for third packing layer, 22 for flow controller, 23 for first temperature detector, 24 for second temperature detector, 25 for first electrically controlled valve, 26 for waste gas circulation pipeline, 27 for ammonia concentration detector, and 28 for second electrically controlled valve. Detailed Implementation
[0015] This utility model is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this utility model and the actual situation.
[0016] Unless otherwise specified, all equipment and devices used in this invention are existing and commonly known in the field. For example, wastewater stripping towers and ammonia scrubbing towers are existing and commonly known equipment.
[0017] In this utility model, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.
[0018] The present invention will be further described below with reference to the embodiments and accompanying drawings: Example 1: As shown in the attached document Figure 1As shown, the device for improving the absorption effect of the ammonia scrubbing tower in the melamine unit includes a wastewater stripping tower 1, a first heat exchanger 2, a second heat exchanger 3, and an ammonia scrubbing tower 4. The inlet of the wastewater stripping tower 1 is fixedly connected to an ammonia-containing wastewater inlet pipeline 5, the top outlet of the wastewater stripping tower 1 is fixedly connected to an ammonia gas outlet pipeline 6, the bottom outlet of the wastewater stripping tower 1 is fixedly connected to a first treatment pipeline 7 between the bottom outlet of the wastewater stripping tower 1 and the inlet of the first heat exchanger 2, the outlet of the first heat exchanger 2 is fixedly connected to a second treatment pipeline 8 between the outlet of the first heat exchanger 2 and the inlet of the second heat exchanger 3, the second treatment pipeline 8 is fixedly connected to a demineralized water inlet pipeline 9, a spray device is provided on the inner side of the upper part of the ammonia scrubbing tower 4, a third treatment pipeline 10 is fixedly connected to the outlet of the second heat exchanger 3 and the inlet of the spray device, the bottom inlet of the ammonia scrubbing tower 4 is fixedly connected to an ammonia-containing waste gas inlet pipeline 11, and the top outlet of the ammonia scrubbing tower 4 is fixedly connected to an venting pipeline 12.
[0019] The existing melamine plant's ammonia scrubbing tower 4 uses only demineralized water as the absorbent, with a consumption of 22.5 t / h. Furthermore, the demineralized water consumption is 3 t for producing one ton of melamine. Additionally, the wastewater stripping tower 1 in the melamine plant needs to send 18 t / h of purified wastewater to the outside.
[0020] This innovative invention combines a wastewater stripping tower 1 with an ammonia scrubbing tower 4 and adds a first heat exchanger 2 and pipelines. The purified wastewater in the wastewater stripping tower 1 is recycled and reused. After being cooled by the first heat exchanger 2, the purified wastewater is mixed with demineralized water as an absorbent, greatly reducing the consumption of demineralized water. The purified wastewater in the wastewater stripping tower 1 is also reused. After this invention is put into use, the consumption of demineralized water is reduced from 22.5 t / h to 5 t / h. For the production of one ton of melamine, the consumption of demineralized water is reduced from 3 t to less than 0.1 t. The wastewater stripping tower 1 discharges 18 t / h of purified wastewater to the outside world, achieving complete recycling and reuse.
[0021] The device for improving the absorption efficiency of the ammonia scrubbing tower 4 in the above-mentioned melamine unit can be further optimized and / or improved according to actual needs: Example 2: Its difference from Example 1 is as follows: (See attached) Figure 1 As shown, the cooling medium inlet of the first heat exchanger 2 is fixedly connected to the raw water inlet pipeline 13, and the cooling medium outlet of the first heat exchanger 2 is fixedly connected to the raw water outlet pipeline 14. The cooling medium inlet of the second heat exchanger 3 is fixedly connected to the cooling circulating water inlet pipeline 15, and the cooling medium outlet of the second heat exchanger 3 is fixedly connected to the cooling circulating water outlet pipeline 16. Depending on the requirements, both the first heat exchanger 2 and the second heat exchanger 3 are conventional plate heat exchangers.
[0022] During operation, by adding a first heat exchanger 2, and using low-temperature raw water from the melamine unit as the cooling medium (the raw water temperature in the melamine unit is 8℃ to 17℃), the raw water serves as a good refrigerant to cool the purified wastewater transported to the bottom of the wastewater stripping tower 1. This wastewater is then mixed with demineralized water and sent to the second heat exchanger 3 for further cooling. This ensures the temperature of the absorbent, and the lower temperature of the absorbent guarantees the absorption effect of the ammonia scrubbing tower. Furthermore, it significantly reduces the consumption of the cooling medium (cooling circulating water) in the second heat exchanger 3. Currently, the existing ammonia scrubbing tower uses cooling circulating water as the cooling medium for cooling the absorbent (demineralized water), with a consumption rate of 119 t / h. After the implementation of this invention, the consumption of the cooling medium (cooling circulating water) in the second heat exchanger 3 is only 30 t / h, significantly reducing the amount of cooling circulating water used.
[0023] Example 3: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1 , 2 As shown, the spraying device includes a liquid distribution plate 17 and a liquid distribution nozzle 18. The liquid distribution plate 17 is provided with a liquid distribution chamber. The upper side of the liquid distribution plate 17 is provided with a liquid inlet that can communicate with the liquid distribution chamber. A third processing pipeline 10 is fixedly connected between the outlet of the second heat exchanger 3 and the liquid inlet of the spraying device. Several liquid outlets are provided on the lower side of the liquid distribution chamber. A liquid distribution nozzle 18 is fixedly installed on the lower side of the liquid distribution plate 17 corresponding to each liquid outlet.
[0024] During use, the absorbent is evenly distributed inside the ammonia scrubbing tower 4 through the spray device, which fully contacts the ammonia-containing waste gas in a counter-current manner to improve the absorption effect. In addition, the spray device can be removed for easy cleaning and replacement.
[0025] Example 4: Its difference from Examples 1 to 3 is as follows: (See attached) Figure 1 As shown, the ammonia scrubbing tower 4 located below the spraying device is equipped with a first packing layer 19, a second packing layer 20 and a third packing layer 21. The packing of the first packing layer 19 and the second packing layer 20 are both Pall ring packing with a diameter of 0.625 inches, and the packing inside the third packing layer 21 is Pall ring packing with a diameter of 1 inch.
[0026] During operation, since the existing ammonia scrubbing tower 4 uses 1.5-inch diameter packing, reducing the packing size increases the gas-liquid contact area, resulting in better absorption. The third packing layer 21 is located at the bottom of the ammonia scrubbing tower 4, close to the ammonia-containing waste gas inlet. The ammonia-containing waste gas may contain particulate matter or impurities, and the anti-clogging performance of medium-diameter Pall ring packing reduces maintenance frequency. The first packing layer 19 and the second packing layer 20 are located at the top of the ammonia scrubbing tower 4. The gas in the upper packing layer is relatively clean, with a low risk of clogging; therefore, small-diameter packing is selected to improve the absorption effect.
[0027] Example 5: It differs from Examples 1 to 4 in that: as shown in the appendix Figure 1 As shown, the third treatment pipeline 10 is equipped with a flow controller 22 and a first temperature detector 23, the demineralized water inlet pipeline 9 is equipped with a first electric control valve 25, the first electric control valve 25 is interlocked with the flow controller 22, and the top of the ammonia scrubbing tower 4 is equipped with a second temperature detector 24.
[0028] During use, the first temperature detector 23 can detect the temperature of the absorbent in real time; the second temperature detector 24 monitors the temperature at the top of the ammonia scrubbing tower 4 in real time; when the flow controller 22 detects that the flow rate of the absorbent is lower than the limit value, it interlocks the opening of the first solenoid valve 25 to replenish the demineralized water into the second heat exchanger 3 in a timely manner.
[0029] Example 6: Its difference from Examples 1 to 5 is as follows: (See attached) Figure 1 As shown, an exhaust pipeline 12 and an ammonia-containing exhaust gas inlet pipeline 11 are fixedly connected by an exhaust gas circulation pipeline 26. An ammonia concentration detector 27 is installed on the exhaust pipeline 12, and a second electrically controlled valve 28 is installed on the exhaust gas circulation pipeline 26. The ammonia concentration detector 27 and the second electrically controlled valve 28 are interlocked.
[0030] During use, when the ammonia concentration detector 27 detects that the ammonia concentration in the purified waste gas exceeds the limit, the second electric control valve 28 is interlocked and opened. The ammonia-containing waste gas returns to the ammonia scrubbing tower 4 through the waste gas circulation pipeline 26 for further treatment, making the waste gas discharged from the ammonia scrubbing tower 4 safer and more environmentally friendly.
[0031] Depending on the needs, the pipelines and equipment of the ammonia scrubbing tower absorption enhancement device of the melamine unit may also be equipped with conventional valves, thermometers and pressure gauges known in the art, as required by production.
[0032] The above technical features constitute the embodiments of this utility model, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.
[0033] The usage process of this utility model is as follows: First, ammonia-containing wastewater from the melamine unit is sent to wastewater stripping tower 1 for stripping. The ammonia-containing gas at the top of wastewater stripping tower 1 is sent to the subsequent ammonium carbamate solution unit for treatment. The wastewater purified at the bottom of wastewater stripping tower 1 is sent to the first heat exchanger 2 for cooling via the first treatment pipeline 7. After cooling, the purified wastewater is mixed with demineralized water and used as an absorbent. It is then sent to the second heat exchanger 3 via the second treatment pipeline 8 for further cooling. When the first temperature detector 23 detects that the temperature of the absorbent has dropped to ≤20℃, the absorbent is sent to the spray device in ammonia scrubbing tower 4 via the third treatment pipeline 10. Then, the ammonia-containing waste gas from the bottom of ammonia scrubbing tower 4 is counter-currently absorbed by the absorbent sprayed from the top spray device. The purified waste gas is vented through the vent pipeline 12. When the ammonia concentration detector 27 detects that the ammonia concentration in the purified waste gas exceeds the limit, the second electrically controlled valve 28 is interlocked and opened, and the ammonia-containing waste gas returns to the ammonia scrubbing tower 4 through the waste gas circulation pipeline 26 for further treatment.
Claims
1. A device for improving the absorption effect of an ammonia scrubbing column of a tri-amine plant, characterized in that The system includes a wastewater stripping tower, a first heat exchanger, a second heat exchanger, and an ammonia scrubbing tower. The inlet of the wastewater stripping tower is fixedly connected to an ammonia-containing wastewater inlet pipeline, the top outlet of the wastewater stripping tower is fixedly connected to an ammonia gas outlet pipeline, the bottom outlet of the wastewater stripping tower is fixedly connected to the inlet of the first heat exchanger via a first treatment pipeline, the outlet of the first heat exchanger is fixedly connected to the inlet of the second heat exchanger via a second treatment pipeline, and a demineralized water inlet pipeline is fixedly connected to the second treatment pipeline. A spray device is installed on the inner side of the upper part of the ammonia scrubbing tower, the outlet of the second heat exchanger is fixedly connected to the inlet of the spray device via a third treatment pipeline, the bottom inlet of the ammonia scrubbing tower is fixedly connected to an ammonia-containing waste gas inlet pipeline, and the top outlet of the ammonia scrubbing tower is fixedly connected to an venting pipeline.
2. The device of claim 1, wherein The first heat exchanger has a fixed connection between its cooling medium inlet and a raw water inlet pipeline, and a fixed connection between its cooling medium outlet and a raw water outlet pipeline. The second heat exchanger has a fixed connection between its cooling medium inlet and a cooling circulating water inlet pipeline, and a fixed connection between its cooling medium outlet and a cooling circulating water outlet pipeline.
3. The device according to claim 1 or 2, characterized in that The spraying device includes a liquid distribution plate and liquid distribution nozzles. The liquid distribution plate has a liquid distribution chamber inside, and an inlet that can communicate with the liquid distribution chamber is provided on the upper side of the liquid distribution plate. A third processing pipeline is fixedly connected between the outlet of the second heat exchanger and the inlet of the spraying device. Several liquid outlets are provided on the lower side of the liquid distribution chamber, and a liquid distribution nozzle is fixedly installed on the lower side of the liquid distribution plate corresponding to each liquid outlet.
4. The device for improving the absorption effect of the ammonia scrubbing tower in a melamine unit according to claim 1 or 2, characterized in that... The ammonia scrubbing tower located below the spraying device has a first packing layer, a second packing layer, and a third packing layer. The first and second packing layers are filled with Pall rings with a diameter of 0.625 inches, while the third packing layer is filled with Pall rings with a diameter of 1 inch.
5. The device of claim 3, wherein The ammonia scrubbing tower located below the spraying device has a first packing layer, a second packing layer, and a third packing layer. The first and second packing layers are filled with Pall rings with a diameter of 0.625 inches, while the third packing layer is filled with Pall rings with a diameter of 1 inch.
6. The device for increasing the absorption effect of the ammonia washing tower of the triamine plant according to claim 1 or 2 or 5, characterized in that The third treatment pipeline is equipped with a flow controller and a first temperature detector. The demineralized water inlet pipeline is equipped with a first electrically controlled valve, which is interlocked with the flow controller. The top of the ammonia scrubbing tower is equipped with a second temperature detector.
7. The device of claim 3, wherein The third treatment pipeline is equipped with a flow controller and a first temperature detector. The demineralized water inlet pipeline is equipped with a first electrically controlled valve, which is interlocked with the flow controller. The top of the ammonia scrubbing tower is equipped with a second temperature detector.
8. The device of claim 4, wherein The third treatment pipeline is equipped with a flow controller and a first temperature detector. The demineralized water inlet pipeline is equipped with a first electrically controlled valve, which is interlocked with the flow controller. The top of the ammonia scrubbing tower is equipped with a second temperature detector.
9. The triamine plant ammonia scrubbing column absorption effect enhancement device according to claim 1 or 2 or 5 or 7 or 8, characterized in that An exhaust pipeline is fixedly connected to the ammonia-containing waste gas inlet pipeline. An ammonia concentration detector is installed on the exhaust pipeline, and a second electrically controlled valve is installed on the waste gas recirculation pipeline. The ammonia concentration detector and the second electrically controlled valve are interlocked.
10. The device of claim 6, wherein An exhaust pipeline is fixedly connected to the ammonia-containing waste gas inlet pipeline. An ammonia concentration detector is installed on the exhaust pipeline, and a second electrically controlled valve is installed on the waste gas recirculation pipeline. The ammonia concentration detector and the second electrically controlled valve are interlocked.