Internal flushing device for urea evaporation equipment
By using gas-phase condensate as the flushing medium in the urea evaporation equipment and combining with the automatic control of the DCS controller, the problem of difficult control of the flushing medium of the evaporation equipment in the urea production is solved, and the stability of the evaporation process and the improvement of product quality is achieved.
Patent Information
- Application Number
- CN202422403263.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-07-18
- Estimated Expiration
- 2034-09-30
AI Technical Summary
In the existing urea production process, the temperature of the flushing medium of the evaporation equipment is not easy to control, which easily causes a sudden drop in the evaporation temperature, affecting the process stability and product quality, and is difficult to meet the requirements of the national standard GB2440-2017.
The internal flushing device of the urea evaporation device is used to use the gas-phase condensate of the evaporation device as the flushing medium, and the condensed liquid is formed through a first-stage evaporation condenser and a second-stage evaporation condenser. The inner wall of the equipment is flushed with the flushing water formed after the temperature is raised by the hydrolysis heater, and automatic control is achieved through the DCS controller.
It effectively solves the problem of sudden drop in evaporation temperature caused by low temperature of the flushing medium, improves the stability of the evaporation process and product quality, complies with the national standard GB2440-2017, and reduces the system's water replenishment.
Smart Images
Figure CN223112335U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of urea production, and is an internal flushing device for a urea evaporation device. Background Technique
[0002] Urea is an important chemical product, which is widely used in the fields of agriculture, chemical industry, medicine, etc. In the urea production process, the evaporation system is an essential subsystem for purifying high-concentration molten urea liquid.
[0003] At present, the generation of condensates in the urea production process not only affects the stable operation of the production process, but also directly affects the quality of urea products. Therefore, the treatment of condensates inside the evaporation device is of great significance for the safe operation of the urea evaporation process. At present, the flushing medium for the evaporation device in the urea production process is mainly steam or high-temperature water. In some urea production processes, low-concentration and low-temperature ammonia water or urea solution is used as the flushing medium. However, during the flushing process, it is difficult to control the evaporation temperature, and the operation is difficult, which is likely to cause a sudden drop in the evaporation temperature and process fluctuations. The control of the flushing time and the dosage of the flushing medium is particularly important for the quality of urea products. Excessive flushing will inevitably result in a high water content in the urea products, and the product quality does not meet the standard of GB2440-2017.
[0004] Therefore, it is necessary to research and invent a suitable flushing medium and flushing method to flush the relevant equipment of the urea evaporation system, prevent the formation of excessive condensates, make the urea products meet the standard of GB2440-2017, and ensure the more stable operation of the urea evaporation system. Summary of the Invention
[0005] The utility model provides an internal flushing device for a urea evaporation device, which overcomes the above-mentioned deficiencies of the prior art and can effectively solve the problems of difficult condensate flushing and flushing affecting the quality of urea products existing in the existing urea evaporation device.
[0006] The technical solution of the utility model is realized by the following measures: An internal flushing device for a urea evaporation device, comprising a first-stage heater, a first-stage evaporation separator, a second-stage heater, a second-stage evaporation separator, a first-stage evaporation condenser, a second-stage evaporation condenser, a condensate tank, and a hydrolysis heater. The bottom inlet of the first-stage heater is fixedly connected to a first urea liquid pipeline. The upper outlet of the first-stage heater and the upper inlet of the first-stage evaporation separator are fixedly connected through a short pipeline. The bottom outlet of the first-stage evaporation separator and the bottom inlet of the second-stage heater are fixedly connected by a second urea liquid pipeline. The upper outlet of the second-stage heater and the upper inlet of the second-stage evaporation separator are fixedly connected through a short pipeline. The bottom outlet of the second-stage evaporation separator is fixedly connected to a urea pipeline. The top outlet of the first-stage evaporation separator and the first inlet at the top of the condensate tank are fixedly connected by a first gas-phase pipeline. The top outlet of the second-stage evaporation separator and the second inlet at the top of the condensate tank are fixedly connected by a second gas-phase pipeline. The lower outlet of the condensate tank and the bottom inlet of the hydrolysis heater are fixedly connected by a first condensate pipeline. The top outlet of the hydrolysis heater and the first inlet at the top of the first-stage evaporation separator are fixedly connected by a first flushing pipeline. The first flushing pipeline and the first inlet at the top of the second-stage evaporation separator are fixedly connected by a second flushing pipeline.
[0007] The following is a further optimization or / and improvement of the above technical solution of the utility model:
[0008] A third flushing pipeline is fixedly connected between the first flushing pipeline between the second flushing pipeline and the first-stage evaporation separator and the first gas-phase pipeline. A fourth flushing pipeline is fixedly connected between the first flushing pipeline between the third flushing pipeline and the second flushing pipeline and the second inlet of the first-stage evaporation separator. A fifth flushing pipeline is fixedly connected between the first flushing pipeline between the second flushing pipeline and the hydrolysis heater and the second inlet of the second-stage evaporation separator. A sixth flushing pipeline is fixedly connected between the first flushing pipeline between the fifth flushing pipeline and the hydrolysis heater and the third inlet of the second-stage evaporation separator.
[0009] The outlet of the first gas-phase pipeline is fixedly connected to a first-stage evaporation condenser. The bottom outlet of the first-stage evaporation condenser and the first inlet at the top of the condensate tank are fixedly connected by a second condensate pipeline. The outlet of the second gas-phase pipeline is fixedly connected to a second-stage evaporation condenser. The bottom outlet of the second-stage evaporation condenser and the second inlet at the top of the condensate tank are fixedly connected by a third condensate pipeline.
[0010] A condensate pump is fixedly installed on the first condensate pipeline.
[0011] The above further includes a hydrolysis tower. A fourth condensate pipeline is fixedly connected between the first flushing pipeline between the sixth flushing pipeline and the hydrolysis heater and the upper inlet of the hydrolysis tower. The top outlet of the hydrolysis tower is fixedly connected to a tail gas recovery pipeline. The bottom outlet of the hydrolysis tower is fixedly connected to a sewage pipeline. The lower inlet of the hydrolysis tower is fixedly connected to a steam pipeline.
[0012] A first flushing valve is fixedly arranged on the first flushing pipeline between the third flushing pipeline and the first-stage evaporation separator. Second flushing valves, third flushing valves, fourth flushing valves, fifth flushing valves, and sixth flushing valves are respectively and fixedly arranged on the second flushing pipeline, the third flushing pipeline, the fourth flushing pipeline, the fifth flushing pipeline, and the sixth flushing pipeline. A total flushing water valve is fixedly arranged on the first flushing pipeline between the sixth flushing pipeline and the hydrolysis heater. A condensate valve is fixedly arranged on the fourth condensate pipeline.
[0013] A remote temperature gauge is fixedly arranged on the first flushing pipeline between the fourth condensate pipeline and the hydrolysis heater. A flow regulating valve and a remote flowmeter are successively and fixedly arranged on the first condensate pipeline between the condensate pump and the hydrolysis heater in the direction of the medium flow.
[0014] It further includes a DCS controller. The first flushing valve, the second flushing valve, the third flushing valve, the fourth flushing valve, the fifth flushing valve, the sixth flushing valve, the remote temperature gauge, the remote flowmeter, and the flow regulating valve are all electrically connected to the DCS controller.
[0015] The utility model has a reasonable and compact structure and is convenient to use. It uses the vapor condensate of the evaporator as the flushing medium for the evaporation equipment, solves the problem that the low temperature of the flushing medium is likely to cause a sudden drop in the evaporation temperature, reduces the system makeup water volume during the entire evaporation process, increases the ammonia partial pressure during the evaporation process to inhibit the generation of by-product condensates, and has the characteristics of economy, environmental protection, safety, and stability. Description of the Drawings
[0016] Appendix Figure 1 is a schematic process flow diagram of the utility model.
[0017] Appendix Figure 1The encodings in it are as follows: 1 is a section of heater, 2 is a section of evaporation separator, 3 is a second-stage heater, 4 is a second-stage evaporation separator, 5 is a first-stage evaporation condenser, 6 is a second-stage evaporation condenser, 7 is a condensate tank, 8 is a condensate pump, 9 is a hydrolysis heater, 10 is a hydrolysis tower, 11 is a first urea liquid pipeline, 12 is a second urea liquid pipeline, 13 is a urea pipeline, 14 is a first gas pipeline, 15 is a second gas pipeline, 16 is a first condensate pipeline, 17 is a second condensate pipeline, 18 is a third condensate pipeline, 19 is a first flushing pipeline, 20 is a second flushing pipeline, 21 is a tail gas recovery pipeline, 22 is a sewage pipeline, 23 is a steam pipeline, 24 is a third flushing pipeline, 25 is a fourth flushing pipeline, 26 is a fifth flushing pipeline, 27 is a sixth flushing pipeline, 28 is a fourth condensate pipeline, 29 is a first flushing valve, 30 is a second flushing valve, 31 is a third flushing valve, 32 is a fourth flushing valve, 33 is a fifth flushing valve, 34 is a sixth flushing valve, 35 is a total flushing water valve, 36 is a condensate valve, 37 is a remote temperature gauge, 38 is a remote flowmeter, 39 is a flow regulating valve. Detailed implementation manners
[0018] The present utility model is not limited by the following embodiments, and the specific implementation manners can be determined according to the technical solution of the present utility model and the actual situation.
[0019] In the present utility model, unless otherwise specified, the used equipment and devices are all the existing well-known and commonly used equipment and devices in the art.
[0020] In the present utility model, for the convenience of description, the description of the relative position relationship of each component is carried out according to the layout mode of the attached Figure 1 drawing of the specification. For example, the position relationships such as front, back, up, down, left, and right are determined according to the layout direction of the attached Figure 1 drawing of the specification.
[0021] The present utility model will be further described below in conjunction with the embodiments and the drawings:
[0022] Embodiment 1: As shown in the attached Figure 1As shown in the figure, the internal flushing device of the urea evaporation equipment includes a first-stage heater 1, a first-stage evaporation separator 2, a second-stage heater 3, a second-stage evaporation separator 4, a first-stage evaporation condenser 5, a second-stage evaporation condenser 6, a condensate tank 7, and a hydrolysis heater 9. The bottom inlet of the first-stage heater 1 is fixedly connected to a first urea liquid pipeline 11. There is a fixed connection through a short pipeline between the upper outlet of the first-stage heater 1 and the upper inlet of the first-stage evaporation separator 2. There is a fixed connection between the bottom outlet of the first-stage evaporation separator 2 and the bottom inlet of the second-stage heater 3 through a second urea liquid pipeline 12. There is a fixed connection through a short pipeline between the upper outlet of the second-stage heater 3 and the upper inlet of the second-stage evaporation separator 4. The bottom outlet of the second-stage evaporation separator 4 is fixedly connected to a urea pipeline 13. There is a fixed connection between the top outlet of the first-stage evaporation separator 2 and the first inlet at the top of the condensate tank 7 through a first gas-phase pipeline 14. There is a fixed connection between the top outlet of the second-stage evaporation separator 4 and the second inlet at the top of the condensate tank 7 through a second gas-phase pipeline 15. There is a fixed connection between the lower outlet of the condensate tank 7 and the bottom inlet of the hydrolysis heater 9 through a first condensate pipeline 16. There is a fixed connection between the top outlet of the hydrolysis heater 9 and the first inlet at the top of the first-stage evaporation separator 2 through a first flushing pipeline 19. There is a fixed connection between the first flushing pipeline 19 and the first inlet at the top of the second-stage evaporation separator 4 through a second flushing pipeline 20.
[0023] As required, the main substances contained in the gas-phase medium evaporated from the tops of the first-stage evaporation separator 2 and the second-stage evaporation separator 4 are water, ammonia, CO2, etc. They enter the condensate tank 7 in the form of ammonium bicarbonate condensate. After being heated by the hydrolysis heater 9, the ammonium bicarbonate condensate forms flushing water. The temperature of the flushing water after heat exchange in the hydrolysis heater 9 is 128°C and the pressure is 1.1 MPa. The flushing water flushes the first-stage evaporation separator 2, the second-stage evaporation separator 4, and their gas-phase pipelines through the first flushing pipeline 19 and the second flushing pipeline 20. Since the flushing water contains ammonia with a concentration of about 1.7%, the ammonia partial pressure during the evaporation process is increased through flushing, thereby inhibiting the generation of by-product condensates.
[0024] According to actual needs, the above internal flushing device of the urea evaporation equipment can be further optimized and / or improved:
[0025] Example 2: The difference from Example 1 is that as shown in the appendix Figure 1As shown in the figure, a third flushing pipeline 24 is fixedly connected between the first flushing pipeline 19 between the second flushing pipeline 20 and the first-stage evaporation separator 2 and the first gas-phase pipeline 14. A fourth flushing pipeline 25 is fixedly connected between the first flushing pipeline 19 between the third flushing pipeline 24 and the second flushing pipeline 20 and the second inlet of the first-stage evaporation separator 2. A fifth flushing pipeline 26 is fixedly connected between the first flushing pipeline 19 between the second flushing pipeline 20 and the hydrolysis heater 9 and the second inlet of the second-stage evaporation separator 4. A sixth flushing pipeline 27 is fixedly connected between the first flushing pipeline 19 between the fifth flushing pipeline 26 and the hydrolysis heater 9 and the third inlet of the second-stage evaporation separator 4.
[0026] Example 3: The difference from Examples 1 to 2 is that as shown in the appendix Figure 1 As shown in the figure, the outlet of the first gas-phase pipeline 14 is fixedly connected to a first-stage evaporation condenser 5. A second condensate pipeline 17 is fixedly connected between the bottom outlet of the first-stage evaporation condenser 5 and the first inlet at the top of the condensate tank 7. The outlet of the second gas-phase pipeline 15 is fixedly connected to a second-stage evaporation condenser 6. A third condensate pipeline 18 is fixedly connected between the bottom outlet of the second-stage evaporation condenser 6 and the second inlet at the top of the condensate tank 7.
[0027] Example 4: The difference from Examples 1 to 3 is that as shown in the appendix Figure 1 As shown in the figure, a condensate pump 8 is fixedly installed on the first condensate pipeline 16.
[0028] Example 5: The difference from Examples 1 to 4 is that as shown in the appendix Figure 1 As shown in the figure, it further includes a hydrolysis tower 10. A fourth condensate pipeline 28 is fixedly connected between the first flushing pipeline 19 between the sixth flushing pipeline 27 and the hydrolysis heater 9 and the upper inlet of the hydrolysis tower 10. The top outlet of the hydrolysis tower 10 is fixedly connected to a tail gas recovery pipeline 21. The bottom outlet of the hydrolysis tower 10 is fixedly connected to a sewage pipeline 22. The lower inlet of the hydrolysis tower 10 is fixedly connected to a steam pipeline 23.
[0029] As needed, a part of the flushing water enters the hydrolysis tower 10 for analysis and separation, and the ammonia gas analyzed is returned to the urea production system through the tail gas recovery pipeline 21.
[0030] Example 6: The difference from Examples 1 to 5 is that as shown in the appendix Figure 1As shown, a first flush valve 29 is fixedly arranged on the first flush pipeline 19 between the third flush pipeline 24 and the first-stage evaporation separator 2. Second flush valves 30, third flush valves 31, fourth flush valves 32, fifth flush valves 33, and sixth flush valves 34 are fixedly arranged on the second flush pipeline 20, the third flush pipeline 24, the fourth flush pipeline 25, the fifth flush pipeline 26, and the sixth flush pipeline 27 respectively in sequence. A total flush water valve 35 is fixedly arranged on the first flush pipeline 19 between the sixth flush pipeline 27 and the hydrolysis heater 9. A condensate valve 36 is fixedly arranged on the fourth condensate pipeline 28.
[0031] Example 7: The difference from Examples 1 to 6 is that as shown in the appendix Figure 1 As shown, a remote temperature gauge 37 is fixedly arranged on the first flush pipeline 19 between the fourth condensate pipeline 28 and the hydrolysis heater 9. A flow regulating valve 39 and a remote flowmeter 38 are fixedly arranged on the first condensate pipeline 16 between the condensate pump 8 and the hydrolysis heater 9 in sequence according to the medium flow direction.
[0032] Example 8: The difference from Examples 1 to 7 is that as shown in the appendix Figure 1 As shown, it further includes a DCS controller. The first flush valve 29, the second flush valve 30, the third flush valve 31, the fourth flush valve 32, the fifth flush valve 33, the sixth flush valve 34, the remote temperature gauge 37, the remote flowmeter 38, and the flow regulating valve 39 are all electrically connected to the DCS controller. An interlock is arranged between the remote flowmeter 38 and the flow regulating valve 39.
[0033] As needed, the model of the DCS controller can be the CS3000 controller produced by Yokogawa Corporation of Japan.
[0034] During use, keep the total flush water valve 35 open. The first flush valve 29 controls the flushing of the upper part of the head of the first-stage evaporation separator 2, and the second flush valve 30 controls the flushing at the inlet of the second gas pipeline 15. Both valves are in the normally open state. The third flush valve 31 controls the flushing of the first gas pipeline 14, the fourth flush valve 32 controls the flushing of the lower part of the head of the first-stage evaporation separator 2, the fifth flush valve 33 controls the flushing of the head of the second-stage evaporation separator 4, and the sixth flush valve 34 controls the flushing of the feed volute of the second-stage evaporation separator 4. The DCS controller executes the flushing program every two hours, and each position is flushed for 20s to 30s each time.
[0035] As needed, on each pipeline and equipment of the internal flushing device of this urea evaporation equipment, conventional valves, thermometers, pressure gauges, etc. well-known and commonly used in the art can also be set according to production needs.
[0036] The above technical features respectively constitute the embodiments of the present invention, which have strong adaptability and implementation effects. Non-essential technical features can be increased or decreased according to actual needs to meet the requirements of different situations.
[0037] The usage process of the embodiment of the utility model: First, the gas-phase media evaporated from the tops of the first-stage evaporation separator 2 and the second-stage evaporation separator 4 respectively form condensate after passing through the first-stage evaporation condenser 5 and the second-stage evaporation condenser 6, and enter the condensate tank 7; then, the condensate enters the hydrolysis heater 9 through the condensate pump 8 and is heated to form flushing water; finally, the flushing water flushes the inner walls of the heads, the feed volutes and the first gas pipeline 14 of the first-stage evaporation separator 2 and the second-stage evaporation separator 4.
Claims
1. An internal flushing device for a urea evaporation equipment, characterized in that It includes a first-stage heater, a first-stage evaporation separator, a second-stage heater, a second-stage evaporation separator, a first-stage evaporation condenser, a second-stage evaporation condenser, a condensate tank, and a hydrolysis heater. The bottom inlet of the first-stage heater is fixedly connected to a first urea solution pipeline. There is a fixed connection through a short pipeline between the upper outlet of the first-stage heater and the upper inlet of the first-stage evaporation separator. There is a fixed connection between the bottom outlet of the first-stage evaporation separator and the bottom inlet of the second-stage heater through a second urea solution pipeline. There is a fixed connection through a short pipeline between the upper outlet of the second-stage heater and the upper inlet of the second-stage evaporation separator. The bottom outlet of the second-stage evaporation separator is fixedly connected to a urea pipeline. There is a fixed connection between the top outlet of the first-stage evaporation separator and the first inlet at the top of the condensate tank through a first gas-phase pipeline. There is a fixed connection between the top outlet of the second-stage evaporation separator and the second inlet at the top of the condensate tank through a second gas-phase pipeline. There is a fixed connection between the lower outlet of the condensate tank and the bottom inlet of the hydrolysis heater through a first condensate pipeline. There is a fixed connection between the top outlet of the hydrolysis heater and the first inlet at the top of the first-stage evaporation separator through a first flushing pipeline. There is a fixed connection between the first flushing pipeline and the first inlet at the top of the second-stage evaporation separator through a second flushing pipeline.
2. The internal flushing device of the urea evaporation equipment according to claim 1, characterized in that There is a fixed connection between the first flushing pipeline between the second flushing pipeline and the first-stage evaporation separator and the first gas-phase pipeline through a third flushing pipeline. There is a fixed connection between the first flushing pipeline between the third flushing pipeline and the second flushing pipeline and the second inlet of the first-stage evaporation separator through a fourth flushing pipeline. There is a fixed connection between the first flushing pipeline between the second flushing pipeline and the hydrolysis heater and the second inlet of the second-stage evaporation separator through a fifth flushing pipeline. There is a fixed connection between the first flushing pipeline between the fifth flushing pipeline and the hydrolysis heater and the third inlet of the second-stage evaporation separator through a sixth flushing pipeline.
3. The internal flushing device of the urea evaporation equipment according to claim 1 or 2, characterized in that The outlet of the first gas-phase pipeline is fixedly connected to a first-stage evaporation condenser. There is a fixed connection between the bottom outlet of the first-stage evaporation condenser and the first inlet at the top of the condensate tank through a second condensate pipeline. The outlet of the second gas-phase pipeline is fixedly connected to a second-stage evaporation condenser. There is a fixed connection between the bottom outlet of the second-stage evaporation condenser and the second inlet at the top of the condensate tank through a third condensate pipeline.
4. The internal flushing device of the urea evaporation equipment according to claim 1 or 2, characterized in that A condensate pump is fixedly installed on the first condensate pipeline.
5. The internal flushing device of the urea evaporation equipment according to claim 3, characterized in that A condensate pump is fixedly installed on the first condensate pipeline.
6. The internal flushing device for urea evaporation equipment according to claim 2 or 5, characterized in that It further includes a hydrolysis tower. There is a fixed connection between the first flushing pipeline between the sixth flushing pipeline and the hydrolysis heater and the upper inlet of the hydrolysis tower through a fourth condensate pipeline. The top outlet of the hydrolysis tower is fixedly connected to a tail gas recovery pipeline. The bottom outlet of the hydrolysis tower is fixedly connected to a sewage pipeline. The lower inlet of the hydrolysis tower is fixedly connected to a steam pipeline.
7. The internal flushing device of the urea evaporation equipment according to claim 3, characterized in that It further includes a hydrolysis tower. There is a fixed connection between the first flushing pipeline between the sixth flushing pipeline and the hydrolysis heater and the upper inlet of the hydrolysis tower through a fourth condensate pipeline. The top outlet of the hydrolysis tower is fixedly connected to a tail gas recovery pipeline. The bottom outlet of the hydrolysis tower is fixedly connected to a sewage pipeline. The lower inlet of the hydrolysis tower is fixedly connected to a steam pipeline.
8. The internal flushing device of the urea evaporation equipment according to claim 6, characterized in that A first flushing valve is fixedly arranged on the first flushing pipeline between the third flushing pipeline and the first-stage evaporation separator. Second flushing valves, third flushing valves, fourth flushing valves, fifth flushing valves, and sixth flushing valves are respectively fixedly arranged on the second flushing pipeline, the third flushing pipeline, the fourth flushing pipeline, the fifth flushing pipeline, and the sixth flushing pipeline. A total flushing water valve is fixedly arranged on the first flushing pipeline between the sixth flushing pipeline and the hydrolysis heater. A condensate valve is fixedly arranged on the fourth condensate pipeline.
9. The internal flushing device for urea evaporation equipment according to claim 7 or 8, characterized in that A remote temperature gauge is fixedly arranged on the first flushing pipeline between the fourth condensate pipeline and the hydrolysis heater. A flow regulating valve and a remote flowmeter are successively fixedly arranged on the first condensate pipeline between the condensate pump and the hydrolysis heater according to the medium flow direction.
10. The internal flushing device of the urea evaporation equipment according to claim 9, characterized in that It further includes a DCS controller. The first flushing valve, the second flushing valve, the third flushing valve, the fourth flushing valve, the fifth flushing valve, the sixth flushing valve, the remote temperature gauge, the remote flowmeter, and the flow regulating valve are all electrically connected to the DCS controller. An interlock is arranged between the remote flowmeter and the flow regulating valve.