Ammonia water analysis and hydrolysis device
By designing an ammonia water desorption and hydrolysis device that combines multi-stage heat exchangers and steam ejectors, the problem of insufficient ammonia water treatment capacity in urea production was solved, achieving efficient reduction of ammonia water concentration and steam recovery, thereby improving the device's processing capacity and economic benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YANKUANG XINJIANG COAL CHEM CO LTD
- Filing Date
- 2025-07-09
- Publication Date
- 2026-06-02
AI Technical Summary
In the existing urea production process, the ammonia desorption and hydrolysis unit cannot meet the high-load ammonia treatment requirements generated by the addition of the melamine unit and the urea medium-pressure system, and the ammonia concentration exceeds the original design capacity.
An ammonia water desorption and hydrolysis device was designed, including an ammonia water tank, a primary heat exchanger, a flash tank, a desorption tower, and a secondary heat exchanger. By combining multi-stage heat exchange and steam ejectors, by-product steam is used as a heat source to increase the temperature of the ammonia water and reduce its concentration. Combined with a PLC control system to optimize the process, efficient ammonia water desorption is achieved.
The ammonia water treatment capacity was increased from 60 m³/h to 65 m³/h, the amount of desorption wastewater was reduced, production costs were saved, and efficient ammonia water concentration reduction and steam recovery were achieved.
Smart Images
Figure CN224307842U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of nitrogen fertilizer manufacturing technology and is an ammonia water desorption and hydrolysis device. Background Technology
[0002] A coal chemical company in Xinjiang has launched a 600,000-ton-per-year methanol-ammonia co-production project using multi-nozzle coal-water slurry pressurized gasification technology. The project is equipped with three multi-nozzle opposed-type coal-water slurry gasifiers, two operating and one on standby, producing 300,000 tons of methanol, 300,000 tons of synthetic ammonia (intermediate product), and 520,000 tons of urea annually. The multi-nozzle coal-water slurry pressurized gasification technology uses bituminous coal as raw material. In the multi-nozzle opposed-type coal-water slurry gasifier, coal-water slurry and pure oxygen react under high temperature and high pressure to produce coal water gas, whose main components are carbon monoxide and hydrogen. After dust removal and washing, the gas is sent to a shift conversion and low-temperature methanol washing section for further processing to obtain purified gas, which is then used to synthesize methanol in the methanol synthesis section. In addition to the existing capacity, a melamine unit and a medium-pressure urea unit have been added.
[0003] In the melamine production process using urea as a raw material, during the concentration and evaporation of the dilute melamine crystal slurry, ammonia dissolved in the slurry is stripped and blown out. The blown-out ammonia is absorbed and mixed with fresh ammonia. Urea plants typically have a desorption system to treat the ammonia water generated during urea synthesis. The original design of the urea desorption hydrolysis system could handle a maximum of 55 Nm³ / h of ammonia water (when the ammonia concentration is <15%). However, with the addition of the melamine project and the new medium-pressure system to the urea plant, the actual production system generates approximately 60 Nm³ / h of ammonia water. Furthermore, the ammonia concentration has reached around 16%, making the original desorption hydrolysis system insufficient to meet production needs.
[0004] Therefore, it is essential to research and invent a high-capacity ammonia desorption and hydrolysis device. Summary of the Invention
[0005] This invention provides an ammonia water desorption and hydrolysis device that overcomes the shortcomings of the prior art and can effectively solve the problem that the existing ammonia water desorption and hydrolysis devices in the urea production process cannot meet the production load.
[0006] The technical solution of this utility model is achieved through the following measures: an ammonia water desorption and hydrolysis device, comprising an ammonia water tank, a primary heat exchanger, a flash tank, a desorption tower, and a secondary heat exchanger. A first ammonia water delivery pipeline is fixedly connected between the bottom outlet of the ammonia water tank and the bottom inlet of the primary heat exchanger. A second ammonia water delivery pipeline is fixedly connected between the top outlet of the primary heat exchanger and the bottom inlet of the secondary heat exchanger. A third ammonia water delivery pipeline is fixedly connected between the top outlet of the secondary heat exchanger and the upper inlet of the flash tank. A fourth ammonia water delivery pipeline is fixedly connected between the bottom outlet of the flash tank and the upper inlet of the desorption tower. A first desorption wastewater delivery pipeline is fixedly connected between the bottom outlet of the desorption tower and the upper inlet of the primary heat exchanger. A second desorption wastewater delivery pipeline is fixedly connected to the bottom outlet of the primary heat exchanger.
[0007] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution:
[0008] The above also includes a steam ejector, a flash steam pipeline is fixedly connected between the top outlet of the flash tank and the bottom inlet of the steam ejector, a mixed gas pipeline is fixedly connected to the left outlet of the steam ejector, a desorption gas pipeline is fixedly connected between the top outlet of the desorption tower and the mixed gas pipeline, and a first steam pipeline is fixedly connected to the right inlet of the steam ejector.
[0009] A fifth ammonia water delivery pipeline is fixedly connected between the first ammonia water delivery pipeline and the second ammonia water delivery pipeline.
[0010] The upper inlet of the aforementioned secondary heat exchanger is fixedly connected to a second steam pipeline, the bottom outlet of the secondary heat exchanger is fixedly connected to a steam condensate pipeline, and the bottom inlet of the analytical column is fixedly connected to a third steam pipeline.
[0011] A first thermometer is fixedly installed on the second ammonia water delivery pipeline between the fifth ammonia water delivery pipeline and the secondary heat exchanger; a second thermometer is fixedly installed on the third ammonia water delivery pipeline; a third thermometer is fixedly installed on the first analytical wastewater delivery pipeline; a first temperature regulating valve is fixedly installed on the fifth ammonia water delivery pipeline; and a second temperature regulating valve is fixedly installed on the second steam pipeline. Interlocks are respectively installed between the first thermometer and the first temperature regulating valve, and between the second thermometer and the second temperature regulating valve.
[0012] An ammonia delivery pump is fixedly installed on the first ammonia delivery pipeline between the aforementioned ammonia tank and the fifth ammonia delivery pipeline.
[0013] The above also includes a PLC controller, which is equipped with a DCS control system. The first thermometer, the second thermometer, the third thermometer, the first regulating valve, the second temperature regulating valve, and the ammonia water delivery pump are all connected to the PLC controller.
[0014] This utility model has a reasonable and compact structure and is easy to use. It utilizes the by-product steam generated during the synthesis of urea in the synthesis system as the heat source for the secondary heat exchanger to increase the temperature of the ammonia water, thereby heating the ammonia water entering the desorption tower from 100°C to 130°C. The flash evaporation tank allows for the preliminary recovery of ammonia and carbon dioxide from the ammonia water, reducing the concentration of ammonia water entering the desorption tower. This meets the production load requirements of the existing ammonia water desorption and hydrolysis process, while also reducing the amount of steam condensate in the desorption tower, thus reducing wastewater discharge and recovering some of the steam condensate. Attached Figure Description
[0015] Appendix Figure 1 This is a schematic diagram of the process flow of this utility model.
[0016] Appendix Figure 1 The codes in the diagram are as follows: 1 for ammonia water tank, 2 for primary heat exchanger, 3 for flash tank, 4 for stripping tower, 5 for secondary heat exchanger, 6 for first ammonia water delivery pipeline, 7 for second ammonia water delivery pipeline, 8 for third ammonia water delivery pipeline, 9 for fourth ammonia water delivery pipeline, 10 for first stripping wastewater delivery pipeline, 11 for second stripping wastewater delivery pipeline, 12 for flash vapor pipeline, 13 for mixed gas pipeline, 14 for stripping gas pipeline, 15 for fifth ammonia water delivery pipeline, 16 for second steam pipeline, 17 for steam condensate pipeline, 18 for third steam pipeline, 19 for first thermometer, 20 for second thermometer, 21 for third thermometer, 22 for first temperature regulating valve, 23 for second temperature regulating valve, 24 for ammonia water delivery pump, 25 for steam ejector, and 26 for third steam pipeline. Detailed Implementation
[0017] 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.
[0018] Unless otherwise specified, all equipment and devices used in this invention are existing, publicly known, and commonly used equipment and devices in the field.
[0019] 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.
[0020] The present invention will be further described below with reference to the embodiments and accompanying drawings:
[0021] Example 1: As shown in the attached document Figure 1As shown, the ammonia water desorption and hydrolysis device includes an ammonia water tank 1, a primary heat exchanger 2, a flash tank 3, a desorption tower 4, and a secondary heat exchanger 5. A first ammonia water delivery pipeline 6 is fixedly connected between the bottom outlet of the ammonia water tank 1 and the bottom inlet of the primary heat exchanger 2. A second ammonia water delivery pipeline 7 is fixedly connected between the top outlet of the primary heat exchanger 2 and the bottom inlet of the secondary heat exchanger 5. A third ammonia water delivery pipeline 8 is fixedly connected between the top outlet of the secondary heat exchanger 5 and the upper inlet of the flash tank 3. A fourth ammonia water delivery pipeline 9 is fixedly connected between the bottom outlet of the flash tank 3 and the upper inlet of the desorption tower 4. A first desorption wastewater delivery pipeline 10 is fixedly connected between the bottom outlet of the desorption tower 4 and the upper inlet of the primary heat exchanger 2. A second desorption wastewater delivery pipeline 11 is fixedly connected to the bottom outlet of the primary heat exchanger 2.
[0022] In this invention, ammonia water passes sequentially through a primary heat exchanger 2, a secondary heat exchanger 5, and a flash tank 3 before entering a desorption tower 4. The temperature of the ammonia water increases from 100℃ to 130℃, and the ammonia and carbon dioxide in the ammonia water are initially recovered, reducing the ammonia concentration from 16% to about 10%. After passing through the desorption tower 4, the ammonia water yields desorption wastewater with an ammonia nitrogen content ≤50ppm and a conductivity ≤100s / m. This desorption wastewater serves as a heat source for the primary heat exchanger 2, where it exchanges heat with the ammonia water and is then further cooled and reused.
[0023] The above-mentioned ammonia water desorption and hydrolysis device can be further optimized and / or improved according to actual needs:
[0024] Example 2: Its difference from Example 1 is as follows: (See attached) Figure 1 As shown, its difference from Embodiments 1 to 2 is as follows: Figure 1 As shown, it also includes a steam ejector 25, a flash steam pipeline 12 fixedly connected between the top outlet of the flash tank 3 and the bottom inlet of the steam ejector 25, a mixed gas pipeline 13 fixedly connected to the left outlet of the steam ejector 25, a desorption gas pipeline 14 fixedly connected between the top outlet of the desorption tower 4 and the mixed gas pipeline 13, and a first steam pipeline 26 fixedly connected to the right inlet of the steam ejector 25.
[0025] As needed, the steam ejector 25 uses steam (0.4MPa by-product saturated steam generated during the synthesis of urea in the production system) as a power source. The flash vapor separated from the flash tank 3 is drawn by the steam ejector 25 to the mixed gas pipeline 13, and together with the desorption gas from the desorption tower 4, it undergoes reflux condensation. The condensed liquid phase is used as the absorbent and reused, while the non-condensable gas phase goes to the atmospheric pressure absorption tower.
[0026] Example 3: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1 As shown, a fifth ammonia water delivery pipeline 15 is fixedly connected between the first ammonia water delivery pipeline 6 and the second ammonia water delivery pipeline 7.
[0027] According to actual production needs, when the ammonia concentration is very low (below 10%), the ammonia water does not pass through the first-stage heat exchanger 2, but is directly transported into the second-stage heat exchanger 5 through the fifth ammonia water delivery pipeline 15, so as to balance the ammonia water temperature in the desorption tower 4.
[0028] Example 4: Its difference from Examples 1 to 3 is as follows: (See attached) Figure 1 As shown, the upper inlet of the secondary heat exchanger 5 is fixedly connected to the second steam pipeline 16, the bottom outlet of the secondary heat exchanger 5 is fixedly connected to the steam condensate pipeline 17, and the bottom inlet of the analytical tower 4 is fixedly connected to the third steam pipeline 18.
[0029] As needed, the heat carrier of the secondary heat exchanger 5 uses 0.4MPa by-product saturated steam generated during the synthesis of urea in the production system. The steam condensate after heat exchange is recycled to the demineralized water production network via steam condensate pipeline 17.
[0030] Example 5: It differs from Examples 1 to 4 in that, as shown in the appendix... Figure 1 As shown, a first thermometer 19 is fixedly installed on the second ammonia water delivery pipeline 7 between the fifth ammonia water delivery pipeline 15 and the secondary heat exchanger 5; a second thermometer 20 is fixedly installed on the third ammonia water delivery pipeline 8; a third thermometer 21 is fixedly installed on the first analytical wastewater delivery pipeline 10; a first temperature regulating valve 22 is fixedly installed on the fifth ammonia water delivery pipeline 15; and a second temperature regulating valve 23 is fixedly installed on the second steam pipeline 16. Interlocks are respectively installed between the first thermometer 19 and the first temperature regulating valve 22, and between the second thermometer 20 and the second temperature regulating valve 23.
[0031] Example 6: Its difference from Examples 1 to 5 is as follows: (See attached) Figure 1 As shown, an ammonia delivery pump 24 is fixedly installed on the first ammonia delivery pipeline 6 between the ammonia tank 1 and the fifth ammonia delivery pipeline 15.
[0032] Example 7: Its difference from Examples 1 to 6 is as follows: (See attached) Figure 1 As shown, it also includes a PLC controller, in which a DCS control system is installed. The first thermometer 19, the second thermometer 20, the third thermometer 21, the first regulating valve 22, the second temperature regulating valve 23, and the ammonia water delivery pump 24 are all connected to the PLC controller.
[0033] Depending on the needs, the various pipelines and equipment of this ammonia water desorption and hydrolysis unit may also be equipped with conventional valves, thermometers, and pressure gauges known and commonly used in the field. The PLC controller can be a Siemens S7-1500, which is equipped with a Yokogawa CS3000 DCS control system.
[0034] Before and after comparison: For ammonia water with a capacity of 60 m³ / h and a concentration of 15%, the capacity of the device before use was 55 m³ / h; after use, the capacity of the device is 60 m³ / h, the wastewater generated in desorption tower 4 is reduced by 10 t / h, and 576,000 yuan can be saved annually.
[0035] The above technical features constitute various 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.
[0036] The usage process of this utility model embodiment is as follows: First, ammonia water enters the primary heat exchanger 2 and the secondary heat exchanger 5 sequentially through the ammonia water delivery pump 24 to obtain high-temperature ammonia water; then, the high-temperature ammonia water enters the flash tank 3 for preliminary analysis to obtain low-concentration ammonia water and flash vapor; finally, the low-concentration ammonia water enters the analysis tower 4 for analysis and hydrolysis to obtain analysis wastewater and analysis gas. The analysis wastewater serves as the heat source for the primary heat exchanger 2 to heat the ammonia water, and the flash vapor is drawn to the mixed gas pipeline 13 by the steam ejector 25, mixed with the analysis gas, and then reused.
Claims
1. An ammonia water desorption and hydrolysis device, characterized in that... The system includes an ammonia tank, a primary heat exchanger, a flash tank, a stripping tower, and a secondary heat exchanger. A first ammonia supply pipeline is fixedly connected between the bottom outlet of the ammonia tank and the bottom inlet of the primary heat exchanger. A second ammonia supply pipeline is fixedly connected between the top outlet of the primary heat exchanger and the bottom inlet of the secondary heat exchanger. A third ammonia supply pipeline is fixedly connected between the top outlet of the secondary heat exchanger and the upper inlet of the flash tank. A fourth ammonia supply pipeline is fixedly connected between the bottom outlet of the flash tank and the upper inlet of the stripping tower. A first stripping wastewater supply pipeline is fixedly connected between the bottom outlet of the stripping tower and the upper inlet of the primary heat exchanger. A second stripping wastewater supply pipeline is fixedly connected to the bottom outlet of the primary heat exchanger.
2. The ammonia water desorption and hydrolysis apparatus according to claim 1, characterized in that... It also includes a steam ejector, with a flash steam pipeline fixedly connected between the top outlet of the flash tank and the bottom inlet of the steam ejector, a mixed gas pipeline fixedly connected to the left outlet of the steam ejector, a desorption gas pipeline fixedly connected between the top outlet of the desorption tower and the mixed gas pipeline, and a first steam pipeline fixedly connected to the right inlet of the steam ejector.
3. The ammonia water desorption and hydrolysis apparatus according to claim 1 or 2, characterized in that... A fifth ammonia water delivery pipeline is fixedly connected between the first ammonia water delivery pipeline and the second ammonia water delivery pipeline.
4. The ammonia water desorption and hydrolysis apparatus according to claim 1 or 2, characterized in that... The upper inlet of the secondary heat exchanger is fixedly connected to a second steam pipeline, the bottom outlet of the secondary heat exchanger is fixedly connected to a steam condensate pipeline, and the bottom inlet of the analytical tower is fixedly connected to a third steam pipeline.
5. The ammonia water desorption and hydrolysis apparatus according to claim 3, characterized in that... The upper inlet of the secondary heat exchanger is fixedly connected to a second steam pipeline, the bottom outlet of the secondary heat exchanger is fixedly connected to a steam condensate pipeline, and the bottom inlet of the analytical tower is fixedly connected to a third steam pipeline.
6. The ammonia water desorption and hydrolysis apparatus according to claim 4, characterized in that... A first thermometer is fixedly installed on the second ammonia water delivery pipeline between the fifth ammonia water delivery pipeline and the second-stage heat exchanger; a second thermometer is fixedly installed on the third ammonia water delivery pipeline; a third thermometer is fixedly installed on the first analytical wastewater delivery pipeline; a first temperature regulating valve is fixedly installed on the fifth ammonia water delivery pipeline; and a second temperature regulating valve is fixedly installed on the second steam pipeline. Interlocks are respectively installed between the first thermometer and the first temperature regulating valve, and between the second thermometer and the second temperature regulating valve.
7. The ammonia water desorption and hydrolysis apparatus according to claim 5, characterized in that... A first thermometer is fixedly installed on the second ammonia water delivery pipeline between the fifth ammonia water delivery pipeline and the second-stage heat exchanger; a second thermometer is fixedly installed on the third ammonia water delivery pipeline; a third thermometer is fixedly installed on the first analytical wastewater delivery pipeline; a first temperature regulating valve is fixedly installed on the fifth ammonia water delivery pipeline; and a second temperature regulating valve is fixedly installed on the second steam pipeline. Interlocks are respectively installed between the first thermometer and the first temperature regulating valve, and between the second thermometer and the second temperature regulating valve.
8. The ammonia water desorption and hydrolysis apparatus according to claim 5, 6, or 7, characterized in that... An ammonia delivery pump is fixedly installed on the first ammonia delivery pipeline between the ammonia tank and the fifth ammonia delivery pipeline.
9. The ammonia water desorption and hydrolysis apparatus according to claim 8, characterized in that... It also includes a PLC controller, which houses a DCS control system. The first thermometer, second thermometer, third thermometer, first regulating valve, second temperature regulating valve, and ammonia water delivery pump are all connected to the PLC controller.