A kind of ammonia washing tower device for high-pressure melamine ammonia production system
By using process water instead of demineralized water as an ammonia detergent in the high-pressure melamine production system, and by utilizing multi-stage heat exchangers and temperature control, the problems of ammonia emission pollution and process water dilution were solved, achieving efficient ammonia absorption and stable recycling of process water.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HENAN XINLIANXIN FERTILIZER
- Filing Date
- 2025-07-18
- Publication Date
- 2026-07-24
AI Technical Summary
During the high-pressure process of melamine production, ammonia emissions pollute the environment and dilute the process water, leading to the need for ammonia replenishment in the system, creating a vicious cycle.
Process water is used instead of demineralized water as an ammonia scrubbing agent. An ammonia-containing waste gas is absorbed by an ammonia scrubbing tower. The ammonia absorption efficiency is improved by using multi-stage heat exchangers and temperature control. The process water is recycled to avoid pollution emissions.
It effectively solved the problem of ammonia emission pollution, increased the ammonia content in process water, reduced the use of demineralized water, lowered costs, and achieved stable recycling of process water.
Smart Images
Figure CN224541368U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of high-pressure melamine ammonia production technology, specifically an ammonia scrubbing tower device for a high-pressure melamine ammonia production system. Background Technology
[0002] The process water produced during the high-pressure melamine production process contains a certain amount of ammonia. Part of the process water is directly transported outside the boundary area, while the other part is recycled in the system's circulating liquid section.
[0003] Meanwhile, the high-pressure process for producing melamine also generates ammonia-containing waste gas. In traditional technology, demineralized water is used to absorb the ammonia in the waste gas in an ammonia scrubbing tower. However, when the demineralized water is used for ammonia scrubbing, a large amount of ammonia cannot be fully absorbed and is released into the atmosphere, causing environmental pollution. At the same time, the demineralized water (hereinafter referred to as ammonia water) after absorbing ammonia will be recycled in the aforementioned system circulating liquid section.
[0004] The above process has the following defects:
[0005] 1. The defect of directly transporting some process water outside the boundary area can easily cause environmental pollution;
[0006] 2. Because of its low ammonia content, ammonia water entering the circulating liquid section of the system causes dilution of the process water. In severe cases, ammonia needs to be added to ensure the normal operation of the system.
[0007] In summary, the existing high-pressure process for producing melamine not only has the drawback of polluting the environment, but also creates a vicious cycle of "process water discharge leading to ammonia loss - desalination water replenishment for dilution". Utility Model Content
[0008] To overcome the above deficiencies, this utility model provides an ammonia scrubbing tower device for a high-pressure melamine ammonia production system, in order to solve the technical problems existing in the prior art.
[0009] The technical solution adopted by this utility model to solve its technical problem is:
[0010] An ammonia scrubbing tower device for a high-pressure melamine ammonia production system includes an ammonia scrubbing tower body, an ammonia-containing waste gas section and a wastewater decomposer in the high-pressure melamine ammonia production system. The ammonia-containing waste gas section is connected to the gas phase inlet at the bottom of the ammonia scrubbing tower body. The gas phase outlet of the wastewater decomposer is connected to the gas phase inlet of a wastewater stripping tower. The waste liquid outlet of the wastewater stripping tower is connected to the system circulating liquid section of the high-pressure melamine ammonia production system via a first tee. The third end of the first tee is connected to the absorbent inlet at the top of the ammonia scrubbing tower body. A gas phase outlet pipe is provided at the top of the ammonia scrubbing tower body. A liquid phase outlet is provided at the bottom of the ammonia scrubbing tower body and is connected to the system circulating liquid section.
[0011] The beneficial effects of this utility model are as follows: Based on the characteristics of melamine ammonia production using the high-pressure method, this utility model changes the traditional ammonia scrubbing tower's method of absorbing ammonia with demineralized water to using process water from the melamine production process as the ammonia absorbent. The above technical solution can utilize process water to absorb ammonia-containing gas and simultaneously recover the process water after ammonia absorption. This not only effectively solves the problem of ammonia emission polluting the environment, but also increases the ammonia content in the system to meet the needs of melamine production.
[0012] Preferably, a flow meter and a waste liquid cooling unit are sequentially installed between the third end of the first three-way valve and the absorbent inlet at the top of the ammonia scrubbing tower body.
[0013] Preferably, a temperature sensor for detecting the temperature of the waste liquid is provided at the absorbent inlet at the top of the ammonia scrubbing tower body.
[0014] Preferably, the waste liquid cooling unit includes at least a first circulating water heat exchanger, the inlet of which is connected to the outlet of the flow meter, and the outlet of which is connected to a temperature sensor.
[0015] Preferably, a second tee and a third tee are provided between the outlet end of the first circulating water heat exchanger and the temperature sensor, and a first valve, a second circulating water heat exchanger and a second valve are provided sequentially between the third end of the second tee and the third end of the third tee.
[0016] Preferably, a fourth three-way valve is provided between the second circulating water heat exchanger and the second valve, and a fifth three-way valve is provided between the second valve and the third three-way valve. The third end of the fourth three-way valve is connected to the third end of the fifth three-way valve in sequence through the third valve, the bromine cold water heat exchanger and the fourth valve.
[0017] Preferably, a sixth three-way valve and a fifth valve are sequentially provided between the second three-way valve and the third three-way valve, and a seventh three-way valve is sequentially provided between the third valve and the bromine cold water heat exchanger; a shortcut pipe with a sixth valve is provided between the third end of the sixth three-way valve and the third end of the seventh three-way valve.
[0018] Preferably, a seventh valve is provided between the third end of the first tee and the flow meter, and an eighth valve is provided between the third tee and the temperature sensor.
[0019] Preferably, the liquid phase outlet of the ammonia scrubbing tower body is connected to the circulating liquid port in the middle of the ammonia scrubbing tower body through a recirculation pump, an eighth three-way valve, and a third circulating water heat exchanger; the third end of the eighth three-way valve is connected to the circulating liquid section of the system; a demineralized water inlet with a demineralized water pipe is provided above the absorbent inlet of the ammonia scrubbing tower body.
[0020] Preferably, the ammonia-containing waste gas section includes the crystallization section and the drying section in the pressure-process melamine ammonia production system.
[0021] According to the above scheme, an ammonia scrubbing tower device for a high-pressure melamine ammonia production system is manufactured. This invention utilizes the characteristic that melamine process wastewater can absorb ammonia, abandoning the traditional technology of using demineralized water to absorb ammonia in an ammonia scrubbing tower. This not only avoids environmental pollution caused by ammonia discharge but also saves on the use of demineralized water and increases the ammonia content in the process water, achieving stable operation of the melamine ammonia production system while reducing costs (no need for ammonia replenishment). Furthermore, this invention increases the ammonia absorption rate by lowering the temperature of the process water, achieving increased ammonia content in the process water while ensuring gas emissions meet standards. Even further, this invention can monitor the flow rate and temperature of the process water according to actual operating conditions and implement stepped cooling based on the required flow rate and temperature, thereby improving the efficiency of ammonia absorption. Compared with traditional technologies, this invention saves on the use of demineralized water, increases the ammonia absorption rate of ammonia-containing gases, is environmentally friendly, and achieves process water recycling while reducing costs (no need for ammonia replenishment). Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This is a schematic diagram of the structure of this utility model.
[0024] In the diagram: 1. Ammonia scrubbing tower body; 2. Wastewater decomposer; 3. Wastewater stripping tower; 4. System circulating liquid section; 5. Flow meter; 6. Temperature sensor; 7. First circulating water heat exchanger; 8. Second circulating water heat exchanger; 9. Bromine cold water heat exchanger; 10. First tee; 11. Second tee; 12. Third tee; 13. First valve; 14. Second valve; 15. Fourth tee; 16. Fifth tee; 17. Third valve; 18. Fourth valve; 19. Sixth tee; 20. Fifth valve; 21. Seventh tee; 22. Sixth valve; 23. Seventh valve; 24. Eighth valve; 25. Recirculation pump; 26. Eighth tee; 27. Demineralized water pipeline; 28. Crystallization section; 29. Drying section; 30. Gas phase outlet pipeline; 31. Third circulating water heat exchanger. Detailed Implementation
[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.
[0026] The following is in conjunction with the appendix Figure 1 To further describe this application in detail, this utility model is an ammonia scrubbing tower device for a high-pressure melamine ammonia production system. The device includes an ammonia scrubbing tower body 1, an ammonia-containing waste gas section and a wastewater decomposer 2 in the high-pressure melamine ammonia production system. The ammonia-containing waste gas section is connected to the gas phase inlet at the bottom of the ammonia scrubbing tower body 1. The gas phase outlet of the wastewater decomposer 2 is connected to the gas phase inlet of the wastewater stripping tower 3. The waste liquid outlet of the wastewater stripping tower 3 is connected to the system circulating liquid section 4 in the high-pressure melamine ammonia production system through a first three-way valve 10. The third end of the first three-way valve 10 is connected to the absorbent liquid inlet at the top of the ammonia scrubbing tower body 1. A gas phase outlet pipe 30 is provided at the top of the ammonia scrubbing tower body 1. A liquid phase outlet is provided at the bottom of the ammonia scrubbing tower body 1, and the liquid phase outlet is connected to the system circulating liquid section 4. In this invention, the wastewater at the outlet of the wastewater stripping tower 3 is process water. In the above technical solution, part of the process water enters the system circulating liquid section 4 for recycling, and the other part of the process water replaces the traditional demineralized water and enters the ammonia scrubbing tower body 1 to absorb ammonia in the ammonia-containing waste gas generated in the high-pressure melamine ammonia production system. The above process can save the amount of demineralized water used, and at the same time further increase the ammonia content in the process water. It avoids the defect of low ammonia content in the process water after the two streams of process water are mixed in the system circulating liquid section 4. At the same time, the above process can avoid the defect of process water (containing ammonia) being discharged and causing environmental pollution. This invention absorbs ammonia in the gas through process water. In order to improve the ammonia yield, the process water can be recycled, the process water volume can be increased, or the process water temperature can be reduced to avoid the problem of insufficient absorption of ammonia in the gas.
[0027] Furthermore, a flow meter 5 and a waste liquid cooling unit are sequentially installed between the third end of the first three-way valve 10 and the absorbent inlet at the top of the ammonia scrubbing tower body 1. This invention monitors the flow rate of the process water by setting the flow meter 5 and cools the process water through the waste liquid cooling unit. These measures can satisfy the requirement of fully absorbing ammonia from the gas under different operating conditions. When the amount of gas to be absorbed is small, the process water flow rate can be reduced and / or the cold source energy consumption can be reduced while cooling the process water. When the amount of gas to be absorbed is large, the process water flow rate can be increased and / or the process water can be deeply cooled to improve the ammonia yield. It should be noted that the waste liquid cooling unit described in this invention can adjust the temperature of the process water according to the actual operating conditions. This adjustment of the process water temperature can be achieved by using a heat exchanger. For example, when only one heat exchanger is used, the process water temperature can be adjusted by whether process water enters the heat exchanger or by the flow rate of process water entering the heat exchanger. When multiple heat exchangers are used, they can be connected in series or in parallel to adjust the final process water temperature.
[0028] Furthermore, a temperature sensor 6 for detecting the temperature of the waste liquid is installed at the absorbent inlet at the upper part of the ammonia scrubbing tower body 1. This invention uses the temperature sensor 6 at the absorbent inlet at the upper part of the ammonia scrubbing tower body 1 to detect the temperature of the process water, enabling timely adjustment when the temperature does not match the amount of gas to be absorbed.
[0029] Furthermore, the waste liquid cooling unit includes at least a first circulating water heat exchanger 7. The inlet of the first circulating water heat exchanger 7 is connected to the outlet of the flow meter 5, and the outlet of the first circulating water heat exchanger 7 is connected to the temperature sensor 6. The waste liquid cooling unit of this invention includes at least a first circulating water heat exchanger 7. In actual use, the temperature of the process water can be adjusted through the first circulating water heat exchanger 7. For example, when cooling of the process water is not required, the process water only passes through the first circulating water heat exchanger 7, while the circulating water does not enter the first circulating water heat exchanger 7. In this case, the first circulating water heat exchanger 7 is only used as a channel. When cooling of the process water is required, the process water and circulating water can enter their respective channels for heat exchange. When the temperature of the process water needs to be adjusted, this can be achieved by increasing or decreasing the amount of circulating water.
[0030] Furthermore, a second three-way valve 11 and a third three-way valve 12 are provided between the outlet end of the first circulating water heat exchanger 7 and the temperature sensor 6. A first valve 13, a second circulating water heat exchanger 8, and a second valve 14 are sequentially provided between the third end of the second three-way valve 11 and the third end of the third three-way valve 12. This invention can also use two circulating water heat exchangers for heat exchange, and the specific heat exchange method can be flexibly adjusted according to the actual requirements of the process water.
[0031] Furthermore, a fourth three-way valve 15 is provided between the second circulating water heat exchanger 8 and the second valve 14, and a fifth three-way valve 16 is provided between the second valve 14 and the third three-way valve 12. The third end of the fourth three-way valve 15 is connected to the third end of the fifth three-way valve 16 in sequence through the third valve 17, the bromine cold water heat exchanger 9, and the fourth valve 18. In addition to using two circulating water heat exchangers, a bromine cold water heat exchanger 9 can also be installed to deeply cool the process water using bromine cold water as a cold source. This method allows the process water temperature to remain within a wide threshold range, enabling flexible adjustment of the process water temperature based on the amount of gas to be absorbed. This adjustment not only avoids the defect of some unabsorbed ammonia being directly emitted and polluting the air, but also increases the ammonia content in the process water to meet the requirements of stable melamine production.
[0032] Furthermore, a sixth tee 19 and a fifth valve 20 are sequentially provided between the second tee 11 and the third tee 12, and a seventh tee 21 is sequentially provided between the third valve 17 and the bromine cold water heat exchanger 9; a shortcut pipe with a sixth valve 22 is provided between the third end of the sixth tee 19 and the third end of the seventh tee 20.
[0033] Furthermore, a seventh valve 23 is provided between the third end of the first tee 10 and the flow meter 5, and an eighth valve 24 is provided between the third tee 12 and the temperature sensor 6.
[0034] Furthermore, the liquid phase outlet of the ammonia scrubbing tower body 1 is connected to the circulating liquid port in the middle of the ammonia scrubbing tower body 1 via a recirculation pump 25, an eighth three-way valve 26, and a third circulating water heat exchanger 31. The third end of the eighth three-way valve 26 is connected to the system circulating liquid section 4. A demineralized water inlet with a demineralized water pipe 27 is provided above the absorbent inlet of the ammonia scrubbing tower body 1. When related equipment malfunctions, ammonia in the gas can be urgently absorbed through the demineralized water pipe 27 to avoid environmental pollution.
[0035] Furthermore, the ammonia-containing waste gas section includes the crystallization section 28 and the drying section 29 in the pressure melamine ammonia production system.
[0036] The specific working process of this utility model is as follows: The ammonia-containing tail gas produced by the crystallization section 28 and the drying section 29 enters the ammonia scrubbing tower body 1 through the corresponding pipelines and the gas phase inlet at the bottom of the ammonia scrubbing tower body 1. The waste liquid produced in the wastewater decomposer 2 can enter the system's recovery tank. The waste gas enters the wastewater stripping tower 3. After stripping, the gas phase of the waste gas can enter the urea production system for recovery. Part of the liquid phase enters the system's circulating liquid section 4 for recycling, and the other part of the process water replaces the traditional demineralized water and enters the ammonia scrubbing tower body 1 through the flow meter 5, the waste liquid cooling unit, and the absorption liquid inlet at the top of the ammonia scrubbing tower body 1. The above-mentioned gas phase and liquid phase come into countercurrent contact and absorb the ammonia in the tail gas. The absorbed liquid phase can be recycled through the recirculation pump 25, the eighth three-way valve 26, and the third circulating water heat exchanger 31, or it can enter the system's circulating liquid section 4 for recycling through the recirculation pump 25 and the eighth three-way valve 26. In the actual production process, it can be adjusted according to... The temperature of the process water can be adjusted by controlling the amount of ammonia-containing tail gas. For example, the process water can directly enter the ammonia scrubbing tower body 1 through the first circulating water heat exchanger 7, the fifth valve 20, and the eighth valve 24; or the process water can directly enter the ammonia scrubbing tower body 1 through the first circulating water heat exchanger 7, the first valve 13, the second circulating water heat exchanger 8, the second valve 14, and the eighth valve 24; or the process water can directly enter the ammonia scrubbing tower body 1 through the first circulating water heat exchanger 7, the first valve 13, the second circulating water heat exchanger 8, the third valve 17, the bromine cold water heat exchanger 9, the fourth valve 18, and the eighth valve 24; or the process water can directly enter the ammonia scrubbing tower body 1 through the first circulating water heat exchanger 7, the sixth valve 22, the bromine cold water heat exchanger 9, the fourth valve 18, and the eighth valve 24. Simultaneously, this invention can also adjust the flow rate of the cold source medium passing through the above heat exchangers, or allow multiple parallel flow of process water, to achieve flexible adjustment of the process water temperature. Compared with traditional technologies, this invention has the advantages of saving the amount of demineralized water used, improving the ammonia absorption rate of ammonia-containing gases, being environmentally friendly, and achieving the recycling of process water while reducing costs (without the need for ammonia replenishment).
[0037] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.
Claims
1. An ammonia scrubbing tower device for a high-pressure melamine ammonia production system, the device comprising an ammonia scrubbing tower body (1), an ammonia-containing waste gas section and a wastewater decomposer in the high-pressure melamine ammonia production system (2), characterized in that: The ammonia-containing waste gas section is connected to the gas phase inlet at the bottom of the ammonia scrubbing tower body (1). The gas phase outlet of the wastewater decomposer (2) is connected to the gas phase inlet of the wastewater stripping tower (3). The waste liquid outlet of the wastewater stripping tower (3) is connected to the system circulating liquid section (4) of the high-pressure melamine ammonia production system through the first three-way valve (10). The third end of the first three-way valve (10) is connected to the absorption liquid inlet at the top of the ammonia scrubbing tower body (1). The top of the ammonia scrubbing tower body (1) is provided with a gas phase outlet pipe (30); The bottom of the ammonia scrubbing tower body (1) is provided with a liquid phase outlet, which is connected to the system circulating liquid section (4).
2. The ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to claim 1, characterized in that: A flow meter (5) and a waste liquid cooling unit are sequentially installed between the third end of the first three-way valve (10) and the absorbent inlet at the top of the ammonia scrubbing tower body (1).
3. The ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to claim 2, characterized in that: A temperature sensor (6) for detecting the temperature of waste liquid is provided at the absorbent inlet of the upper part of the ammonia scrubbing tower body (1).
4. The ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to claim 3, characterized in that: The waste liquid cooling unit includes at least a first circulating water heat exchanger (7), the inlet end of which is connected to the outlet of the flow meter (5), and the outlet end of which is connected to the temperature sensor (6).
5. The ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to claim 4, characterized in that: A second tee (11) and a third tee (12) are provided between the outlet end of the first circulating water heat exchanger (7) and the temperature sensor (6). A first valve (13), a second circulating water heat exchanger (8), and a second valve (14) are provided sequentially between the third end of the second tee (11) and the third end of the third tee (12).
6. The ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to claim 5, characterized in that: A fourth tee (15) is provided between the second circulating water heat exchanger (8) and the second valve (14), and a fifth tee (16) is provided between the second valve (14) and the third tee (12). The third end of the fourth tee (15) is connected to the third end of the fifth tee (16) in sequence through the third valve (17), the bromine cold water heat exchanger (9) and the fourth valve (18).
7. The ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to claim 6, characterized in that: A sixth tee (19) and a fifth valve (20) are sequentially provided between the second tee (11) and the third tee (12). A seventh tee (21) is provided between the third valve (17) and the bromine cold water heat exchanger (9); A shortcut pipe with a sixth valve (22) is provided between the third end of the sixth tee (19) and the third end of the seventh tee (21).
8. The ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to claim 5, characterized in that: A seventh valve (23) is provided between the third end of the first tee (10) and the flow meter (5), and an eighth valve (24) is provided between the third tee (12) and the temperature sensor (6).
9. The ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to claim 1, characterized in that: The liquid outlet of the ammonia scrubbing tower body (1) is connected to the circulating liquid port in the middle of the ammonia scrubbing tower body (1) through the recirculation pump (25), the eighth three-way valve (26) and the third circulating water heat exchanger (31), and the third end of the eighth three-way valve (26) is connected to the circulating liquid section (4) of the system. The ammonia scrubbing tower body (1) has a demineralized water inlet with a demineralized water pipe (27) at the top of the absorbent inlet.
10. An ammonia scrubbing tower device for a high-pressure melamine ammonia production system according to any one of claims 1-9, characterized in that: The ammonia-containing waste gas section includes the crystallization section (28) and the drying section (29) in the pressure melamine ammonia production system.