Cooling energy-saving device for ammonia synthesis
By designing an ammonia synthesis cooling and energy-saving device, and utilizing multi-stage heat exchange and bromine refrigeration unit cooling technology, the problem of high cost of cooling ammonia synthesis gas was solved, achieving efficient cooling and energy-saving effects.
Patent Information
- Application Number
- CN202522181553.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-15
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-10-15
AI Technical Summary
The high cost of cooling ammonia synthesis gas leads to increased costs for nitrogen fertilizer production enterprises.
A cooling and energy-saving device for ammonia synthesis was designed. By combining equipment such as a synthesis compressor, a hot gas heat exchanger, an ammonia synthesis tower, a steam generator, a synthesis water cooler, a cold gas heat exchanger, a chilled water heat exchanger, an ammonia cooling device, and a high-pressure ammonia separator, the device utilizes the high-temperature heat energy carried by the ammonia synthesis gas for multi-stage heat exchange and cooling. It then uses a bromine refrigeration unit and demineralized water for further cooling, ultimately obtaining cryogenic liquid ammonia.
This achieved efficient cooling of ammonia synthesis gas, reduced energy consumption and production costs, and improved economic efficiency.
Smart Images
Figure CN224677808U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of cooling and energy-saving technology for ammonia synthesis loop systems, and is a cooling and energy-saving device for ammonia synthesis. Background Technology
[0002] Nitrogen fertilizer is one of the most important fertilizers in agricultural production. Its core function is to convert free nitrogen in the air into combined nitrogen (such as NH4) that can be absorbed by plants. + NO3 - Modern nitrogen fertilizer production uses ammonia (NH3) as the core intermediate product, and the vast majority of nitrogen fertilizers (such as urea, ammonium nitrate, ammonium bicarbonate, etc.) are produced from ammonia.
[0003] Ammonia (NH3) is produced by synthesizing nitrogen (N2) and hydrogen (H2), and the ammonia synthesis reaction is exothermic. A chemical company uses an ammonia synthesis process to produce ammonia. The outlet gas (syngas) from the ammonia synthesis tower has a temperature of approximately 440℃. The conventional preliminary treatment process for syngas involves using heat exchange equipment to gradually cool the syngas from 440℃ to -10℃, obtaining liquid ammonia which then enters the downstream process system to produce nitrogen fertilizer. As the production capacity of the ammonia synthesis system continues to expand, the demand for cooling medium in the heat exchange equipment also increases, leading to higher costs for cooling the syngas and generating more auxiliary energy consumption. For a 2000-ton-per-day ammonia synthesis unit, the ammonia compressor power is 8523KW, consuming approximately 39.66t / h of 4.0MPa superheated steam. Adding the construction costs of other auxiliary equipment, the cost of cooling the ammonia synthesis unit becomes even higher.
[0004] In summary, the high cost of cooling ammonia synthesis gas has become a pressing technical challenge for nitrogen fertilizer production enterprises. Summary of the Invention
[0005] This invention provides a cooling and energy-saving device for ammonia synthesis, which overcomes the shortcomings of the prior art and can effectively solve the problem of high cost in existing ammonia synthesis gas cooling.
[0006] The technical solution of this utility model is achieved through the following measures: A cooling and energy-saving device for ammonia synthesis, comprising a synthesis compressor, a hot gas heat exchanger, an ammonia synthesis tower, a steam generator, a synthesis water cooler, a cold gas heat exchanger, a chilled water heat exchanger, an ammonia cooling device, and a high-pressure ammonia separator. The inlet of the synthesis compressor is fixedly connected to a raw material gas input pipeline. The hot gas heat exchanger, the synthesis water cooler, and the cold gas heat exchanger all include a tube side and a shell side. A first compressed gas pipeline is fixedly connected between the outlet of the synthesis compressor and the shell-side inlet of the hot gas heat exchanger. A second compressed gas pipeline is fixedly connected between the shell-side outlet of the hot gas heat exchanger and the lower inlet of the ammonia synthesis tower. The bottom outlet of the ammonia synthesis tower is connected to the steam generator... A first syngas pipeline is fixedly connected between the inlets of the units; a second syngas pipeline is fixedly connected between the outlet of the steam generator and the inlet of the hot gas heat exchanger tube side; a third syngas pipeline is fixedly connected between the outlet of the hot gas heat exchanger tube side and the inlet of the syngas water cooler tube side; a fourth syngas pipeline is fixedly connected between the outlet of the syngas water cooler tube side and the inlet of the cold gas heat exchanger tube side; a fifth syngas pipeline is fixedly connected between the outlet of the cold gas heat exchanger tube side and the inlet of the chilled water heat exchanger; a sixth syngas pipeline is fixedly connected between the outlet of the chilled water heat exchanger and the inlet of the ammonia refrigeration unit; and a seventh syngas pipeline is fixedly connected between the outlet of the ammonia refrigeration unit and the inlet of the middle section of the high-pressure ammonia separator.
[0007] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution: The aforementioned synthesis water cooler shell-side inlet is fixedly connected to a circulating water input pipeline, and the synthesis water cooler shell-side outlet is fixedly connected to a circulating water output pipeline; the high-pressure ammonia separator bottom outlet is fixedly connected to a first liquid ammonia output pipeline, the high-pressure ammonia separator top outlet is fixedly connected to a first separation gas pipeline between the cold gas heat exchanger shell-side inlet, and the cold gas heat exchanger shell-side outlet is fixedly connected to a second separation gas pipeline between the synthesis compressor bottom inlet.
[0008] The aforementioned chilled water heat exchange unit includes a chilled water heat exchanger and a bromine chiller unit. The chilled water heat exchanger includes a tube side and a shell side. A fifth syngas pipeline is fixedly connected between the tube side outlet of the chilled gas heat exchanger and the tube side inlet of the chilled water heat exchanger. A sixth syngas pipeline is fixedly connected between the tube side outlet of the chilled water heat exchanger and the inlet of the ammonia refrigeration unit. A chilled water input pipeline is fixedly connected between the top outlet of the bromine chiller unit and the shell side inlet of the chilled water heat exchanger. A chilled water return pipeline is fixedly connected between the shell side outlet of the chilled water heat exchanger and the top inlet of the bromine chiller unit. A waste heat input pipeline is fixedly connected to the upper part of the bromine chiller unit, and a waste heat output pipeline is fixedly connected to the lower part of the bromine chiller unit. A chilled water circulation pump is fixedly installed on the chilled water return pipeline.
[0009] The aforementioned steam generating unit includes a steam superheater, a steam generator, and a boiler feedwater preheater. The steam superheater, steam generator, and boiler feedwater preheater all include a tube side and a shell side. A first syngas pipeline is fixedly connected between the bottom outlet of the ammonia synthesis tower and the tube side inlet of the steam superheater. A ninth syngas pipeline is fixedly connected between the tube side outlet of the steam superheater and the tube side inlet of the steam generator. A tenth syngas pipeline is fixedly connected between the tube side outlet of the steam generator and the tube side inlet of the boiler feedwater preheater. A second syngas pipeline is fixedly connected between the tube side outlet of the boiler feedwater preheater and the tube side inlet of the hot gas heat exchanger.
[0010] The boiler feedwater preheater shell side inlet is fixedly connected to a boiler feedwater pipeline, the boiler feedwater preheater shell side outlet is fixedly connected to the steam generator shell side inlet, the steam generator shell side outlet is fixedly connected to the steam superheater shell side inlet, and the steam superheater shell side outlet is fixedly connected to an overheated steam pipeline.
[0011] The aforementioned ammonia refrigeration unit includes a first ammonia cooler and a second ammonia cooler. Both the first and second ammonia coolers include a tube side and a shell side. A sixth syngas pipeline is fixedly connected between the tube side outlet of the chilled water heat exchanger and the tube side inlet of the first ammonia cooler. An eighth syngas pipeline is fixedly connected between the tube side outlet of the first ammonia cooler and the tube side inlet of the second ammonia cooler. A seventh syngas pipeline is fixedly connected between the tube side outlet of the second ammonia cooler and the middle inlet of the high-pressure ammonia separator.
[0012] The aforementioned ammonia refrigeration unit also includes an ammonia compressor, an evaporative condenser, a liquid ammonia receiving tank, and a liquid ammonia cooler. The evaporative condenser and the liquid ammonia cooler include a tube side and a shell side. A first ammonia gas pipeline is fixedly connected between the top shell side outlet of the first ammonia cooler and the top first inlet of the ammonia compressor. A compressed liquid ammonia pipeline is fixedly connected between the bottom outlet of the ammonia compressor and the tube side inlet of the evaporative condenser. A liquid ammonia condensation pipeline is fixedly connected between the tube side outlet of the evaporative condenser and the top inlet of the liquid ammonia receiving tank. A separated liquid ammonia pipeline is fixedly connected between the bottom outlet of the liquid ammonia receiving tank and the tube side inlet of the liquid ammonia cooler. A first cryogenic liquid ammonia pipeline is fixedly connected between the tube side outlet of the liquid ammonia cooler and the bottom shell side inlet of the first ammonia cooler. A second cryogenic liquid ammonia pipeline is fixedly connected between the bottom shell side outlet of the first ammonia cooler and the bottom shell side inlet of the second ammonia cooler. A second liquid ammonia output pipeline is fixedly connected to the bottom shell side outlet of the second ammonia cooler.
[0013] A second ammonia pipeline is fixedly connected between the top shell-side outlet of the second ammonia cooler and the top second inlet of the ammonia compressor.
[0014] The liquid ammonia receiving tank is equipped with a liquid ammonia heater at the top. The liquid ammonia heater includes a tube side and a shell side. The outlet of the top tube side of the liquid ammonia heater is fixedly connected to an exhaust pipeline. The inlet of the lower shell side of the liquid ammonia heater is fixedly connected to a heat source input pipeline. The outlet of the upper shell side of the liquid ammonia heater is fixedly connected to a heat source output pipeline.
[0015] The shell-side inlet of the aforementioned evaporative condenser is fixedly connected to a demineralized water input pipeline, and the shell-side outlet of the evaporative condenser is fixedly connected to a demineralized water output pipeline; the shell-side inlet of the liquid ammonia cooler is fixedly connected to a cryogenic liquid ammonia input pipeline, and the shell-side outlet of the liquid ammonia cooler is fixedly connected to a cryogenic liquid ammonia output pipeline.
[0016] This utility model has a reasonable and compact structure and is easy to use. It makes full use of the high-temperature heat energy carried by the synthesis gas in the ammonia synthesis section. It can not only perform preliminary heat exchange and cooling of the synthesis gas, but also produce high-grade steam for use by other process systems. Finally, it uses the cold medium generated in the ammonia synthesis production system to cool the synthesis gas again after preliminary cooling, so as to obtain the low-temperature liquid ammonia required by the process. This reduces the cost of cooling ammonia synthesis and improves the economic benefits of ammonia synthesis. Attached Figure Description
[0017] Appendix Figure 1 This is a schematic diagram of the process flow of this utility model.
[0018] The codes in the attached diagram are as follows: 1 for synthesis compressor, 2 for hot gas heat exchanger, 3 for ammonia synthesis tower, 4 for synthesis water cooler, 5 for cold gas heat exchanger, 6 for high-pressure ammonia separator, 7 for raw material gas input pipeline, 8 for first compressed gas pipeline, 9 for second compressed gas pipeline, 10 for first synthesis gas pipeline, 11 for second synthesis gas pipeline, 12 for third synthesis gas pipeline, 13 for fourth synthesis gas pipeline, 14 for fifth synthesis gas pipeline, and 15 for sixth synthesis gas pipeline. 16 is the seventh synthesis gas pipeline, 17 is the circulating water input pipeline, 18 is the circulating water output pipeline, 19 is the first liquid ammonia output pipeline, 20 is the first separated gas pipeline, 21 is the second separated gas pipeline, 22 is the chilled water heat exchanger, 23 is the bromine chiller unit, 24 is the chilled water input pipeline, 25 is the chilled water return pipeline, 26 is the waste heat input pipeline, 27 is the waste heat output pipeline, 28 is the steam superheater, 29 is the steam generator, and 30 is the boiler feedwater preheater. Heaters: 31 is the ninth syngas pipeline, 32 is the tenth syngas pipeline, 33 is the boiler feedwater pipeline, 34 is the high-temperature hot water pipeline, 35 is the saturated steam pipeline, 36 is the superheated steam pipeline, 37 is the first ammonia cooler, 38 is the second ammonia cooler, 39 is the eighth syngas pipeline, 40 is the ammonia compressor, 41 is the evaporative condenser, 42 is the liquid ammonia receiving tank, 43 is the liquid ammonia cooler, 44 is the first ammonia gas pipeline, 45 is the compressed liquid ammonia pipeline, and 46 is the liquid ammonia pipeline. The pipeline includes: condenser line, 47 is the liquid ammonia separation line, 48 is the first cryogenic liquid ammonia line, 49 is the second ammonia line, 50 is the second cryogenic liquid ammonia line, 51 is the second liquid ammonia output line, 52 is the liquid ammonia heater, 53 is the exhaust line, 54 is the heat source input line, 55 is the heat source output line, 56 is the demineralized water input line, 57 is the demineralized water output line, 58 is the cryogenic liquid ammonia input line, 59 is the cryogenic liquid ammonia output line, and 60 is the chilled water circulation pump. Detailed Implementation
[0019] 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.
[0020] Unless otherwise specified, all equipment and devices used in this invention are existing, publicly known, and commonly used equipment and devices in the field.
[0021] 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.
[0022] 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 cooling and energy-saving device for ammonia synthesis includes a synthesis compressor 1, a hot gas heat exchanger 2, an ammonia synthesis tower 3, a steam generator, a synthesis water cooler 4, a cold gas heat exchanger 5, a chilled water heat exchanger, an ammonia cooling unit, and a high-pressure ammonia separator 6. The inlet of the synthesis compressor 1 is fixedly connected to a raw material gas input pipeline 7. The hot gas heat exchanger 2, the synthesis water cooler 4, and the cold gas heat exchanger 5 all include a tube side and a shell side. A first compressed gas pipeline 8 is fixedly connected between the outlet of the synthesis compressor 1 and the shell-side inlet of the hot gas heat exchanger 2. A second compressed gas pipeline 9 is fixedly connected between the shell-side outlet of the hot gas heat exchanger 2 and the lower inlet of the ammonia synthesis tower 3. A third compressed gas pipeline 9 is fixedly connected between the bottom outlet of the ammonia synthesis tower 3 and the inlet of the steam generator. A syngas pipeline 10 is fixedly connected to the outlet of the steam generator and the inlet of the hot gas heat exchanger 2. A second syngas pipeline 11 is fixedly connected to the outlet of the hot gas heat exchanger 2 and the inlet of the syngas water cooler 4. A fourth syngas pipeline 13 is fixedly connected to the outlet of the syngas water cooler 4 and the inlet of the cold gas heat exchanger 5. A fifth syngas pipeline 14 is fixedly connected to the outlet of the cold gas heat exchanger 5 and the inlet of the chilled water heat exchanger. A sixth syngas pipeline 15 is fixedly connected to the outlet of the chilled water heat exchanger and the inlet of the ammonia cooling unit. A seventh syngas pipeline 16 is fixedly connected to the outlet of the ammonia cooling unit and the middle inlet of the high-pressure ammonia separator 6.
[0023] As required, the hot gas heat exchanger 2, the synthesis water cooler 4, and the cold gas heat exchanger 5 are all commonly used shell-and-tube heat exchange equipment in the chemical industry.
[0024] This invention fully utilizes the heat energy (440℃) carried by the ammonia synthesis gas produced by ammonia synthesis tower 3 for heat energy conversion and reuse, obtaining high-grade steam while reducing the temperature of the ammonia synthesis gas itself. After the ammonia synthesis gas is initially cooled, it is gradually cooled to -10℃, and finally the ammonia synthesis gas is separated into gas and liquid to obtain liquid ammonia, thus achieving energy-saving and consumption-reducing production targets.
[0025] The cooling and energy-saving device for ammonia synthesis described above 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 inlet of the shell side of the synthesis water cooler 4 is fixedly connected to a circulating water input pipeline 17, and the outlet of the shell side of the synthesis water cooler 4 is fixedly connected to a circulating water output pipeline 18; the bottom outlet of the high-pressure ammonia separator 6 is fixedly connected to a first liquid ammonia output pipeline 19, the top outlet of the high-pressure ammonia separator 6 is fixedly connected to a first separation gas pipeline 20 between the shell side inlet of the cold gas heat exchanger 5, and the shell side outlet of the cold gas heat exchanger 5 is fixedly connected to a second separation gas pipeline 21 between the bottom inlet of the synthesis compressor 1.
[0026] Example 3: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1As shown, the chilled water heat exchange unit includes a chilled water heat exchanger 22 and a bromine chiller unit 23. The chilled water heat exchanger 22 includes a tube side and a shell side. A fifth syngas pipeline 14 is fixedly connected between the tube side outlet of the cold gas heat exchanger 5 and the tube side inlet of the chilled water heat exchanger 22. A sixth syngas pipeline 15 is fixedly connected between the tube side outlet of the chilled water heat exchanger 22 and the inlet of the ammonia refrigeration unit. A chilled water input pipeline 24 is fixedly connected between the top outlet of the bromine chiller unit 23 and the shell side inlet of the chilled water heat exchanger 22. A chilled water return pipeline 25 is fixedly connected between the shell side outlet of the chilled water heat exchanger 22 and the top inlet of the bromine chiller unit 23. A waste heat input pipeline 26 is fixedly connected to the upper part of the bromine chiller unit 23. A waste heat output pipeline 27 is fixedly connected to the lower part of the bromine chiller unit 23. A chilled water circulation pump 60 is fixedly installed on the chilled water return pipeline 25.
[0027] As required, the bromine chiller unit 23 is a self-heating lithium bromide chiller. The bromine chiller unit 23 cools down the waste heat medium discharged from other process systems to obtain condensate gas. The condensate gas then exchanges heat with the circulating water in the bromine chiller unit 23 to obtain 7°C chilled water. The 7°C chilled water provides cooling medium for the chilled water heat exchanger 22. The temperature of the chilled water discharged from the chilled water heat exchanger 22 is 15°C. The 15°C chilled water is returned to the bromine chiller unit 23 for circulation cooling, further reducing the consumption of cooling medium (liquid ammonia) in the ammonia refrigeration unit, reducing energy waste, and lowering energy consumption.
[0028] The chilled water heat exchanger 22 will cool the ammonia synthesis gas at 29.5°C, reducing the temperature of the ammonia synthesis gas to 14.5°C.
[0029] Example 4: Its difference from Examples 1 to 3 is as follows: (See attached) Figure 1 As shown, the steam generating unit includes a steam superheater 28, a steam generator 29, and a boiler feedwater preheater 30. The steam superheater 28, steam generator 29, and boiler feedwater preheater 30 all include a tube side and a shell side. A first syngas pipeline 10 is fixedly connected between the bottom outlet of the ammonia synthesis tower 3 and the tube side inlet of the steam superheater 28. A ninth syngas pipeline 31 is fixedly connected between the tube side outlet of the steam superheater 28 and the tube side inlet of the steam generator 29. A tenth syngas pipeline 32 is fixedly connected between the tube side outlet of the steam generator 29 and the tube side inlet of the boiler feedwater preheater 30. A second syngas pipeline 11 is fixedly connected between the tube side outlet of the boiler feedwater preheater 30 and the tube side inlet of the hot gas heat exchanger 2.
[0030] Example 5: It differs from Examples 1 to 4 in that, as shown in the appendix... Figure 1As shown, the boiler feedwater preheater 30 shell side inlet is fixedly connected to the boiler feedwater pipeline 33, the boiler feedwater preheater 30 shell side outlet is fixedly connected to the steam generator 29 shell side inlet to the high-temperature hot water pipeline 34, the steam generator 29 shell side outlet is fixedly connected to the steam superheater 28 shell side inlet to the saturated steam pipeline 35, and the steam superheater 28 shell side outlet is fixedly connected to the superheated steam pipeline 36.
[0031] As required, the steam superheater 28, steam generator 29, and boiler feedwater preheater 30 are all commonly used shell-and-tube heat exchangers in the chemical industry.
[0032] The steam superheater 28, steam generator 29, and boiler feedwater preheater 30 utilize the heat energy (440℃) carried by the ammonia synthesis gas to exchange heat with the hot water discharged from other process system equipment (132℃ boiler water) to obtain high-grade steam (superheated steam) while also reducing the temperature of the ammonia synthesis gas itself.
[0033] Example 6: Its difference from Examples 1 to 5 is as follows: (See attached) Figure 1 As shown, the ammonia refrigeration unit includes a first ammonia cooler 37 and a second ammonia cooler 38. Both the first ammonia cooler 37 and the second ammonia cooler 38 include a tube side and a shell side. A sixth syngas pipeline 15 is fixedly connected between the tube side outlet of the chilled water heat exchanger 22 and the tube side inlet of the first ammonia cooler 37. An eighth syngas pipeline 39 is fixedly connected between the tube side outlet of the first ammonia cooler 37 and the tube side inlet of the second ammonia cooler 38. A seventh syngas pipeline 16 is fixedly connected between the tube side outlet of the second ammonia cooler 38 and the middle inlet of the high-pressure ammonia separator 6.
[0034] As required, both the first ammonia cooler 37 and the second ammonia cooler 38 are commonly used shell-and-tube heat exchangers in the chemical industry.
[0035] The first ammonia cooler 37 and the second ammonia cooler 38 gradually cool the ammonia synthesis gas from 14.5°C to -10°C, and then send it to the high-pressure ammonia separator 6 for gas-liquid separation to obtain liquid ammonia.
[0036] Example 7: Its difference from Examples 1 to 6 is as follows: (See attached) Figure 1As shown, the ammonia refrigeration unit also includes an ammonia compressor 40, an evaporative condenser 41, a liquid ammonia receiving tank 42, and a liquid ammonia cooler 43. The evaporative condenser 41 and the liquid ammonia cooler 43 include a tube side and a shell side. A first ammonia gas pipeline 44 is fixedly connected between the top shell side outlet of the first ammonia cooler 37 and the top first inlet of the ammonia compressor 40. A compressed liquid ammonia pipeline 45 is fixedly connected between the bottom outlet of the ammonia compressor 40 and the tube side inlet of the evaporative condenser 41. The tube side outlet of the evaporative condenser 41 is connected to the top inlet of the liquid ammonia receiving tank 42. A liquid ammonia condensation pipeline 46 is fixedly connected between the bottom outlet of the liquid ammonia receiving tank 42 and the tube-side inlet of the liquid ammonia cooler 43. A separation liquid ammonia pipeline 47 is fixedly connected between the tube-side outlet of the liquid ammonia cooler 43 and the bottom shell-side inlet of the first ammonia cooler 37. A second cryogenic liquid ammonia pipeline 50 is fixedly connected between the bottom shell-side outlet of the first ammonia cooler 37 and the bottom shell-side inlet of the second ammonia cooler 38. A second liquid ammonia output pipeline 51 is fixedly connected to the bottom shell-side outlet of the second ammonia cooler 38.
[0037] As required, both the evaporative condenser 41 and the liquid ammonia cooler 43 are commonly used shell-and-tube heat exchangers in the chemical industry.
[0038] Example 8: It differs from Examples 1 to 7 in that: as shown in the appendix Figure 1 As shown, a second ammonia pipeline 49 is fixedly connected between the top shell outlet of the second ammonia cooler 38 and the top second inlet of the ammonia compressor 40.
[0039] Example 9: It differs from Examples 1 to 8 in that: as shown in the appendix Figure 1 As shown, a liquid ammonia heater 52 is installed at the top of the liquid ammonia receiving tank 42. The liquid ammonia heater 52 includes a tube side and a shell side. The outlet of the top tube side of the liquid ammonia heater 52 is fixedly connected to an exhaust pipe 53. The inlet of the lower shell side of the liquid ammonia heater 52 is fixedly connected to a heat source input pipe 54. The outlet of the upper shell side of the liquid ammonia heater 52 is fixedly connected to a heat source output pipe 55.
[0040] As required, the liquid ammonia heater 52 is a commonly used shell-and-tube heat exchanger in the chemical industry.
[0041] Example 10: It differs from Examples 1 to 9 in that, as shown in the appendix... Figure 1 As shown, the shell-side inlet of the evaporative condenser 41 is fixedly connected to a demineralized water input pipeline 56, and the shell-side outlet of the evaporative condenser 41 is fixedly connected to a demineralized water output pipeline 57; the shell-side inlet of the liquid ammonia cooler 43 is fixedly connected to a low-temperature liquid ammonia input pipeline 58, and the shell-side outlet of the liquid ammonia cooler 43 is fixedly connected to a low-temperature liquid ammonia output pipeline 59.
[0042] As required, the cryogenic liquid ammonia input pipeline 58 delivers cryogenic liquid ammonia at a temperature of -7.1℃.
[0043] Depending on the needs, the pipelines and equipment of the ammonia synthesis cooling and energy-saving device may also be equipped with conventional valves, thermometers and pressure gauges known and commonly used in the field, according to production requirements.
[0044] This invention reduces the cost of cooling synthetic ammonia and reduces energy waste. Taking a daily production of 2,000 tons of synthetic ammonia as an example, after this invention is put into use, the load on the ammonia compressor can be reduced, the shaft power of the ammonia compressor can be reduced by 2,317 KW, and the steam consumption can be reduced by 10.38 t / h, thereby saving energy consumption and reducing production costs.
[0045] 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.
[0046] The usage process of this utility model embodiment includes: The first step is that the raw material gas (hydrogen and nitrogen) enters the synthesis compressor 1 through the raw material gas input pipeline 7 for compression, and then enters the shell side of the hot gas heat exchanger 2 through the first compressed gas pipeline 8 for heat exchange and temperature increase to obtain compressed synthesis gas. In the second step, the compressed syngas enters the ammonia synthesis tower 3 through the second compressed gas pipeline 9 to carry out the ammonia synthesis reaction and obtain high-temperature ammonia syngas. The high-temperature ammonia syngas enters the steam superheater 28 tube side, the steam generator 29 tube side and the boiler feedwater preheater 30 tube side in sequence through the first syngas pipeline 10 to gradually exchange heat and cool down, and obtain pre-cooled syngas. In the second step, the boiler water produced by the upstream boiler system enters the shell side of the boiler feedwater preheater 30 through the boiler feedwater pipeline 33 for heat exchange and temperature increase. The resulting high-temperature hot water enters the shell side of the steam generator 29 through the high-temperature hot water pipeline 34 for heat exchange and temperature increase, resulting in saturated steam. The saturated steam enters the shell side of the steam superheater 28 through the saturated steam pipeline 35 for heat exchange and temperature increase, resulting in superheated steam. The superheated steam enters other devices through the superheated steam pipeline 36 to provide steam supply. The third step involves the pre-cooled syngas entering the tube side of the hot gas heat exchanger 2 through the second syngas pipeline 11, where it exchanges heat with the compressed syngas in the shell side of the hot gas heat exchanger 2 and then enters the tube side of the syngas water cooler 4 through the third syngas pipeline 12, where it exchanges heat with the circulating water in the shell side of the syngas water cooler 4 and then obtains the secondary cooled syngas. In the fourth step, the secondary cooled syngas enters the tube side of the cold gas heat exchanger 5 through the fourth syngas pipeline 13, and exchanges heat with the liquid ammonia separation gas discharged from the top of the high-pressure ammonia separator 6 in the shell side of the cold gas heat exchanger 5 to obtain the tertiary cooled syngas. In the fourth step, the liquid ammonia separated gas after heat exchange in the shell side of the cold gas heat exchanger 5 flows back to the synthesis compressor 1 through the second separated gas pipeline 21 for compression. Fifth step: The tertiary cooling syngas enters the tube side of the chilled water heat exchanger 22 through the fifth syngas pipeline 14, and exchanges heat with the chilled water in the shell side of the chilled water heat exchanger 22 to cool down, thus obtaining tertiary cooling syngas. In the fifth step, the chilled water in the shell side of the chilled water heat exchanger 22 is supplied by the bromine chiller unit 23, and the chilled water after heat exchange in the shell side of the chilled water heat exchanger 22 returns to the bromine chiller unit 23 through the chilled water return line 25. Step 6: The four-stage cooling synthesis gas enters the first ammonia cooler 37 tube side and the second ammonia cooler 38 tube side through the sixth synthesis gas pipeline 15 in sequence, and cools and condenses with the low-temperature liquid ammonia in the first ammonia cooler 37 shell side and the second ammonia cooler 38 shell side to obtain the fifth-stage cooling synthesis gas. The sixth step of the process further includes: First, the liquid ammonia condensate in the shell side of the first ammonia cooler 37 and the shell side of the second ammonia cooler 38 enters the ammonia compressor 40 through the first ammonia pipeline 44 and the second ammonia pipeline 49 respectively for compression, and then enters the tube side of the evaporative condenser 41 through the compressed liquid ammonia pipeline 45, where it exchanges heat with the demineralized water condensate in the shell side of the evaporative condenser 41 to obtain liquid ammonia condensate; then, the liquid ammonia condensate enters the liquid ammonia receiving tank 42 through the liquid ammonia condensation pipeline 46 for buffering, and the liquid ammonia heater 52 heats the liquid ammonia receiving tank. The liquid ammonia in tank 42 is heated to remove the gas in the liquid ammonia; then, the liquid ammonia in tank 42 enters the tube side of liquid ammonia cooler 43 through the liquid ammonia separation pipeline 47, where it exchanges heat with the low-temperature liquid ammonia in the shell side of liquid ammonia cooler 43 to obtain liquid ammonia condensate; finally, the liquid ammonia condensate in the tube side of liquid ammonia cooler 43 enters the shell side of first ammonia cooler 37 and the shell side of second ammonia cooler 38 through the first low-temperature liquid ammonia pipeline 48, and the liquid ammonia in the shell side of second ammonia cooler 38 after heat exchange enters the downstream process system through the second liquid ammonia output pipeline 51. In the seventh step, the ammonia synthesis gas, after five cooling cycles, enters the high-pressure ammonia separator 6 through the seventh synthesis gas pipeline 16 for gas-liquid separation. The resulting liquid ammonia product enters the downstream process system through the first liquid ammonia output pipeline 19.
Claims
1. A cooling and energy-saving device for ammonia synthesis, characterized in that... The system includes a synthesis compressor, a hot gas heat exchanger, an ammonia synthesis tower, a steam generator, a synthesis water cooler, a cold gas heat exchanger, a chilled water heat exchanger, an ammonia cooling unit, and a high-pressure ammonia separator. The synthesis compressor inlet is fixedly connected to a raw material gas input pipeline. The hot gas heat exchanger, synthesis water cooler, and cold gas heat exchanger all include a tube side and a shell side. A first compressed gas pipeline is fixedly connected between the synthesis compressor outlet and the shell-side inlet of the hot gas heat exchanger. A second compressed gas pipeline is fixedly connected between the shell-side outlet of the hot gas heat exchanger and the lower inlet of the ammonia synthesis tower. A first synthesis gas pipeline is fixedly connected between the bottom outlet of the ammonia synthesis tower and the inlet of the steam generator. A second syngas pipeline is fixedly connected between the outlet of the steam generator and the inlet of the hot gas heat exchanger tube side; a third syngas pipeline is fixedly connected between the outlet of the hot gas heat exchanger tube side and the inlet of the syngas water cooler tube side; a fourth syngas pipeline is fixedly connected between the outlet of the syngas water cooler tube side and the inlet of the cold gas heat exchanger tube side; a fifth syngas pipeline is fixedly connected between the outlet of the cold gas heat exchanger tube side and the inlet of the chilled water heat exchanger; a sixth syngas pipeline is fixedly connected between the outlet of the chilled water heat exchanger and the inlet of the ammonia cooling unit; and a seventh syngas pipeline is fixedly connected between the outlet of the ammonia cooling unit and the inlet of the middle part of the high-pressure ammonia separator.
2. The cooling and energy-saving device for ammonia synthesis according to claim 1, characterized in that... A circulating water input pipeline is fixedly connected to the shell-side inlet of the synthesis water cooler, and a circulating water output pipeline is fixedly connected to the shell-side outlet of the synthesis water cooler; or / and, a first liquid ammonia output pipeline is fixedly connected to the bottom outlet of the high-pressure ammonia separator, a first separation gas pipeline is fixedly connected between the top outlet of the high-pressure ammonia separator and the shell-side inlet of the cold gas heat exchanger, and a second separation gas pipeline is fixedly connected between the shell-side outlet of the cold gas heat exchanger and the bottom inlet of the synthesis compressor.
3. The cooling and energy-saving device for ammonia synthesis according to claim 1 or 2, characterized in that... The chilled water heat exchange unit includes a chilled water heat exchanger and a bromine refrigeration unit. The chilled water heat exchanger includes a tube side and a shell side. A fifth syngas pipeline is fixedly connected between the tube side outlet of the chilled gas heat exchanger and the tube side inlet of the chilled water heat exchanger. A sixth syngas pipeline is fixedly connected between the tube side outlet of the chilled water heat exchanger and the inlet of the ammonia refrigeration unit. A chilled water input pipeline is fixedly connected between the top outlet of the bromine refrigeration unit and the shell side inlet of the chilled water heat exchanger. A chilled water return pipeline is fixedly connected between the shell side outlet of the chilled water heat exchanger and the top inlet of the bromine refrigeration unit. A waste heat input pipeline is fixedly connected to the upper part of the bromine refrigeration unit. A waste heat output pipeline is fixedly connected to the lower part of the bromine refrigeration unit. A chilled water circulation pump is fixedly installed on the chilled water return pipeline.
4. The cooling and energy-saving device for ammonia synthesis according to claim 1 or 2, characterized in that... The steam generating unit includes a steam superheater, a steam generator, and a boiler feedwater preheater. The steam superheater, steam generator, and boiler feedwater preheater all include a tube side and a shell side. A first syngas pipeline is fixedly connected between the bottom outlet of the ammonia synthesis tower and the tube side inlet of the steam superheater. A ninth syngas pipeline is fixedly connected between the tube side outlet of the steam superheater and the tube side inlet of the steam generator. A tenth syngas pipeline is fixedly connected between the tube side outlet of the steam generator and the tube side inlet of the boiler feedwater preheater. A second syngas pipeline is fixedly connected between the tube side outlet of the boiler feedwater preheater and the tube side inlet of the hot gas heat exchanger.
5. The cooling and energy-saving device for ammonia synthesis according to claim 4, characterized in that... The boiler feedwater preheater shell side inlet is fixedly connected to the boiler feedwater pipeline, the boiler feedwater preheater shell side outlet is fixedly connected to the steam generator shell side inlet, the steam generator shell side outlet is fixedly connected to the steam superheater shell side inlet, and the steam superheater shell side outlet is fixedly connected to the superheated steam pipeline.
6. The cooling and energy-saving device for ammonia synthesis according to claim 3, characterized in that... The ammonia refrigeration unit includes a first ammonia cooler and a second ammonia cooler. Both the first and second ammonia coolers include a tube side and a shell side. A sixth syngas pipeline is fixedly connected between the tube side outlet of the chilled water heat exchanger and the tube side inlet of the first ammonia cooler. An eighth syngas pipeline is fixedly connected between the tube side outlet of the first ammonia cooler and the tube side inlet of the second ammonia cooler. A seventh syngas pipeline is fixedly connected between the tube side outlet of the second ammonia cooler and the middle inlet of the high-pressure ammonia separator.
7. The cooling and energy-saving device for ammonia synthesis according to claim 6, characterized in that... The ammonia refrigeration unit also includes an ammonia compressor, an evaporative condenser, a liquid ammonia receiving tank, and a liquid ammonia cooler. The evaporative condenser and the liquid ammonia cooler include a tube side and a shell side. A first ammonia gas pipeline is fixedly connected between the top shell side outlet of the first ammonia cooler and the top first inlet of the ammonia compressor. A compressed liquid ammonia pipeline is fixedly connected between the bottom outlet of the ammonia compressor and the tube side inlet of the evaporative condenser. A liquid ammonia condensation pipeline is fixedly connected between the tube side outlet of the evaporative condenser and the top inlet of the liquid ammonia receiving tank. A separated liquid ammonia pipeline is fixedly connected between the bottom outlet of the liquid ammonia receiving tank and the tube side inlet of the liquid ammonia cooler. A first cryogenic liquid ammonia pipeline is fixedly connected between the tube side outlet of the liquid ammonia cooler and the bottom shell side inlet of the first ammonia cooler. A second cryogenic liquid ammonia pipeline is fixedly connected between the bottom shell side outlet of the first ammonia cooler and the bottom shell side inlet of the second ammonia cooler. A second liquid ammonia output pipeline is fixedly connected to the bottom shell side outlet of the second ammonia cooler.
8. The cooling and energy-saving device for ammonia synthesis according to claim 7, characterized in that... A second ammonia pipeline is fixedly connected between the top shell-side outlet of the second ammonia cooler and the top second inlet of the ammonia compressor.
9. The cooling and energy-saving device for ammonia synthesis according to claim 7 or 8, characterized in that... A liquid ammonia heater is installed at the top of the liquid ammonia receiving tank. The liquid ammonia heater includes a tube side and a shell side. The outlet of the top tube side of the liquid ammonia heater is fixedly connected to an exhaust pipeline. The inlet of the lower shell side of the liquid ammonia heater is fixedly connected to a heat source input pipeline. The outlet of the upper shell side of the liquid ammonia heater is fixedly connected to a heat source output pipeline.
10. The cooling and energy-saving device for ammonia synthesis according to claim 9, characterized in that... The shell-side inlet of the evaporative condenser is fixedly connected to a demineralized water input pipeline, and the shell-side outlet of the evaporative condenser is fixedly connected to a demineralized water output pipeline; or / and, the shell-side inlet of the liquid ammonia cooler is fixedly connected to a cryogenic liquid ammonia input pipeline, and the shell-side outlet of the liquid ammonia cooler is fixedly connected to a cryogenic liquid ammonia output pipeline.