Ammonia recovery system for low-sulfur gas condensate
By designing an ammonia recovery system for low-sulfur gas condensate including ammonia evaporation tower, primary flash evaporation, backup secondary flash evaporation, ammonia water cooler and scrubber, the problems of equipment blockage, low ammonia separation efficiency and high energy consumption in the prior art are solved, and an efficient and economical ammonia recovery effect is achieved.
Patent Information
- Application Number
- CN202422080795.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-27
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-08-27
AI Technical Summary
The existing ammonia recovery technology of low-sulfur gas condensate has problems such as equipment blockage, low ammonia separation efficiency and high energy consumption. Especially in the process of low-sulfur gas condensate, the process operation and adjustment are difficult, which makes it difficult to ensure the purity of ammonia water.
An ammonia recovery system for low-sulfur gas condensate was designed, including ammonia evaporation tower, primary flash evaporation, backup secondary flash evaporation, ammonia water cooler and scrubber. By setting up a backup secondary flash evaporation and a washing tower, select the combination of first-level flash evaporation or first-level flash + second-level flash evaporation according to the actual working conditions to ensure the purity of ammonia water, and avoid crystallization in the ammonia evaporation tower through the washing tower, improving the ammonia separation efficiency.
The system can effectively ensure the purity of ammonia water, reduce energy consumption, meet the requirements of energy conservation and environmental protection, and avoid equipment blockage and improve ammonia recycling efficiency.
Smart Images
Figure CN222989795U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of ammonia separation and recovery of coal gas condensate, in particular to an ammonia recovery system for low-sulfur coal gas condensate. Background Art
[0002] Coal gasification technology is the main technology for the clean and efficient utilization of raw coal. Coal gas condensate will be generated during the coal gas cooling process. The main impurities in the condensate are NH3 (ammonia), H2S (hydrogen sulfide), and CO2 (carbon dioxide), and also contain inorganic pollutants such as CN- (cyanide) and SCN- (thiocyanate), as well as heterocyclic or polycyclic aromatic organic compounds such as phenol and oil, belonging to refractory industrial wastewater. Therefore, the coal gas condensate must be defatted and ammonia stripped before being further treated by a biochemical station and can be discharged after reaching the standard.
[0003] At present, the ammonia recovery in coal gas condensate generally adopts single-tower pressurized side-line ammonia stripping method and double-tower pressurized ammonia stripping method. The single-tower pressurized side-line ammonia stripping process is simpler and more energy-saving. The steam unit consumption of the double-tower pressurization is higher than that of the single-tower, and the equipment investment is also larger.
[0004] The single-tower pressurized side-line ammonia stripping method uses an ammonia stripping tower to concentrate NH3. Since the separated NH3 contains H2S, several stages of flash distillation and partial condensation processes are set according to the H2S content after the ammonia stripping tower to further remove H2S in NH3, so as to obtain high-purity NH3. At present, for coal gas condensate with relatively high sulfur content, two or three stages of flash distillation and partial condensation processes are mostly connected in series after the ammonia stripping tower, while for low-sulfur coal gas condensate, usually only one stage of flash distillation and partial condensation process is set. Theoretically, for low-sulfur coal gas condensate, ammonia water with > 20wt% can also be obtained by one-stage flash distillation and partial condensation. However, due to the large changes in the condensate feed composition and condensate feed amount, it is difficult to control the process operation and adjustment. Therefore, the ammonia water obtained by one-stage flash condensation sometimes fails to meet the index value requirements.
[0005] The existing ammonia stripping tower also has the following problems: Since NH3 is easily soluble in H2O at room temperature, it forms ammonium sulfate crystals with H2S and ammonium bicarbonate crystals with CO2, which easily cause blockage of equipment and pipelines; moreover, condensers are mostly installed at the top of the ammonia stripping tower, making crystallization easier to occur, and seriously affecting production operation; but if the temperature is higher than the crystallization temperature, NH3 will be entrained in the light component gases such as CO2 and discharged, reducing the ammonia separation efficiency and ammonia recovery. If this part of the gas is returned to the gasification furnace, it is easy to cause ammonia concentration accumulation. Content of the Utility Model
[0006] In view of the above-mentioned shortcomings existing in the existing ammonia recovery from low-sulfur coal gas condensate, the applicant provides an ammonia recovery system for low-sulfur coal gas condensate with a reasonable structure, which is provided with a standby secondary flash evaporation. According to the actual working conditions, primary flash evaporation or the combined use of primary flash evaporation + secondary flash evaporation is selected to ensure the purity of ammonia water. A washing tower is set up to wash the high-temperature ammonia-rich gas in the ammonia distillation tower and absorb the ammonia in the gas. The bottom condensate of the tower is further circulated and stripped to avoid crystallization in the ammonia distillation tower and ensure the ammonia separation efficiency and ammonia recovery.
[0007] The technical solution adopted by the present utility model is as follows:
[0008] An ammonia recovery system for low-sulfur coal gas condensate includes an ammonia distillation tower, a primary flash evaporation, a standby secondary flash evaporation, and an ammonia water cooler. The primary flash evaporation includes an ammonia water pre-cooler I and an ammonia water separation tank I connected to each other. The standby secondary flash evaporation includes an ammonia water pre-cooler II and an ammonia water separation tank II connected to each other. The side-line extraction outlet of the ammonia distillation tower is connected to the hot side of the ammonia water pre-cooler I. The ammonia-rich water vapor outlet of the ammonia water separation tank I is connected to the primary flash evaporation ammonia-rich water vapor extraction pipeline. The primary flash evaporation ammonia-rich water vapor extraction pipeline is connected to the ammonia water cooler through a first gas discharge pipeline. The primary flash evaporation ammonia-rich water vapor extraction pipeline is connected to the ammonia water pre-cooler II of the standby secondary flash evaporation through a second gas discharge pipeline. The ammonia-rich water vapor outlet of the ammonia water separation tank II of the standby secondary flash evaporation is connected to the ammonia water cooler through a third gas discharge pipeline. The ammonia water cooler is connected to the ammonia water out of the battery limit through a dilute ammonia water discharge pipeline. Under normal design working conditions, the standby secondary flash evaporation gas extraction pipeline is closed. When deviating from the design working conditions, the standby secondary flash evaporation gas extraction pipeline is opened. The waste water outlet pipeline at the bottom of the ammonia distillation tower is connected to the hot side of the rich and lean liquid heat exchanger and the bottom cooler, and then connected to the waste water out of the battery limit through a qualified waste water discharge pipeline.
[0009] As a further improvement of the above technical solution:
[0010] An on-line analyzer is provided on the primary flash evaporation ammonia-rich water vapor extraction pipeline. Control valves are respectively provided on the first gas discharge pipeline and the second gas discharge pipeline, and are cascade-controlled with the on-line analyzer. According to the analysis results of the sampled samples, the opening and closing of the standby secondary flash evaporation are controlled.
[0011] The primary flash evaporation ammonia-rich water vapor extraction pipeline is respectively connected to the first gas discharge pipeline and the second gas discharge pipeline. Both the first gas discharge pipeline and the third gas discharge pipeline are connected to the inlet pipeline of the ammonia water cooler.
[0012] A buffer tank and a feed pump are provided before the ammonia distillation tower. A condensate pipeline is connected to the buffer tank. The liquid outlet of the buffer tank is connected to the feed pump. The feed pump is connected to the top of the ammonia distillation tower through a condensate cold feed pipeline. The feed pump is sequentially connected to the cold side of the ammonia water pre-cooler I and the cold side of the rich and lean liquid heat exchanger through a condensate hot feed pipeline and then connected to the middle part of the ammonia distillation tower.
[0013] Before the ammonia distillation column, a filter is also provided. The feed pump is connected to the filter through a filtered feed pipeline, and the filter is connected back to the buffer tank through a filtered discharge pipeline.
[0014] The cooling condensate outlet of the first ammonia water separation tank is connected to the first condensate cooler, and the first condensate cooler is connected back to the buffer tank through a first return pipeline; the cooling condensate outlet of the second ammonia water separation tank is connected to the second condensate cooler, and the second condensate cooler is connected back to the buffer tank through a second return pipeline.
[0015] The gas outlet of the ammonia distillation column is connected to the scrubbing tower through an acid gas discharge pipeline, the waste gas outlet of the scrubbing tower is connected to the outside of the plant through a waste gas discharge pipeline, and the scrubbing liquid outlet of the scrubbing tower is connected to the buffer tank through a scrubbing liquid discharge pipeline; the acid gas extraction temperature of the acid gas discharge pipeline is controlled at 95 - 100 °C.
[0016] The scrubbing water inlet of the scrubbing tower is connected to the waste water outlet pipeline of the ammonia distillation column through a scrubbing water feed pipeline; temperature and pressure detection equipment is provided at the upper part of the scrubbing tower.
[0017] The bottom of the ammonia distillation column is connected to a reboiler, and the reboiler provides heat; a steam condensate inlet is provided on the scrubbing tower, and the steam condensate inlet is connected to the high-temperature condensate discharge pipeline of the reboiler through a steam condensate feed pipeline, and a regulating valve is provided on the steam condensate feed pipeline.
[0018] Trays are provided at the part of the ammonia distillation column corresponding to the side line extraction outlet, and the rest of the column is filled with packing.
[0019] The beneficial effects of the present utility model are as follows:
[0020] The present utility model is provided with a primary flash evaporation and a standby secondary flash evaporation. According to the actual working conditions, the primary flash evaporation or the combination of the primary flash evaporation + secondary flash evaporation is selected for use, which not only ensures the purity of the ammonia water, but also helps to reduce energy consumption and better meets the requirements of energy conservation and environmental protection.
[0021] Before the ammonia distillation column of the present utility model, a buffer tank and a filter are provided. The filter filters the condensate through a circulating filtration method, removing suspended impurities such as oils and ash in the condensate and ensuring the cleanliness of the feed.
[0022] The present utility model uses a scrubbing tower to wash and remove ammonia from the acidic gas of the ammonia distillation column. At the same time, the extraction temperature of the acid gas is controlled to avoid crystallization and ensure the ammonia separation efficiency and ammonia recovery. The scrubbing tower uses the waste water discharged from the ammonia distillation column as the scrubbing water, saving the use of additional scrubbing water, reducing costs and improving economic benefits.
[0023] The ammonia distillation column of the present utility model combines trays and packing, which not only ensures the separation efficiency of the column, but also helps to reduce the overall height of the column and the investment cost of the ammonia distillation column. Description of the Drawings
[0024] Figure 1 This is the system flow block diagram of the present utility model.
[0025] In the figure: 1. Buffer tank; 2. Feed pump; 3. Filter; 4. Ammonia stripping tower; 41. Tray; 42. Packing; 5. Reboiler; 6. Rich and lean liquid heat exchanger; 7. Bottom cooler of the tower; 8. First ammonia water pre-cooler; 9. First ammonia water separation tank; 10. Second ammonia water pre-cooler; 11. Second ammonia water separation tank; 12. First condensate cooler; 13. Second condensate cooler; 14. Ammonia water cooler; 15. Scrubbing tower.
[0026] 101. Condensate pipeline; 102. Filter feed pipeline; 103. Filter discharge pipeline; 104. Cold feed pipeline of condensate; 105. Hot feed pipeline of condensate; 106. Washing water feed pipeline; 107. Qualified wastewater discharge pipeline; 108. First gas discharge pipeline; 109. Second gas discharge pipeline; 110. Third gas discharge pipeline; 111. Dilute ammonia water discharge pipeline; 112. Acid gas discharge pipeline; 113. Waste gas discharge pipeline; 114. Washing liquid discharge pipeline; 115. Steam condensate feed pipeline; 116. First-stage flash rich ammonia water vapor extraction pipeline; 117. First return pipeline; 118. Second return pipeline. Specific embodiments
[0027] The following will describe the specific embodiments of the present utility model with reference to the accompanying drawings.
[0028] As Figure 1 shown, the ammonia recovery system for low-sulfur coal gas condensate of the present utility model includes an ammonia stripping tower 4, a first-stage flash, a standby second-stage flash, an ammonia water cooler 14, and a scrubbing tower 15. The first-stage flash includes a first ammonia water pre-cooler 8 and a first ammonia water separation tank 9 connected to each other. The standby second-stage flash includes a second ammonia water pre-cooler 10 and a second ammonia water separation tank 11 connected to each other. The bottom of the ammonia stripping tower 4 is connected to a reboiler 5, and the reboiler 5 provides the heat source required for ammonia stripping.
[0029] Before the ammonia distillation column 4, a buffer tank 1, a feed pump 2 and a filter 3 are provided. A condensate pipeline 101 is connected to the buffer tank 1. The low-sulfur coal gas condensate and other condensates enter the buffer tank 1 through the condensate pipeline 101. The liquid outlet of the buffer tank 1 is connected to the feed pump 2. The liquid outlet pipeline of the feed pump 2 is divided into three paths: one path is connected to the filter 3 through the filtered feed pipeline 102, and the filter 3 is connected back to the buffer tank 1 through the filtered discharge pipeline 103 to form a condensate self-circulation filtration pipeline to circulate and filter the condensate in the buffer tank 1, removing suspended impurities such as oils and ash in the condensate to ensure the cleanliness of the feed; one path is connected to the top of the ammonia distillation column 4 through the condensate cold feed pipeline 104 to form a cold feed pipeline, and cold coal gas condensate is input from the top of the ammonia distillation column 4; one path is connected to the cold side of the first ammonia water pre-cooler 8 and the cold side of the rich and lean liquid heat exchanger 6 in sequence through the condensate hot feed pipeline 105 and then connected to the middle part of the ammonia distillation column 4 to form a hot feed pipeline. The coal gas condensate is heat-exchanged to a suitable temperature by the first ammonia water pre-cooler 8 and the rich and lean liquid heat exchanger 6 and then input into the ammonia distillation column 4 from the middle part of the ammonia distillation column 4.
[0030] The side line extraction outlet in the middle and lower part of the ammonia distillation column 4 is connected to the hot side of the first ammonia water pre-cooler 8. The rich ammonia water vapor outlet of the first ammonia water separation tank 9 leads out a first-stage flash rich ammonia water vapor extraction pipeline 116. After the first-stage flash rich ammonia water vapor extraction pipeline 116 is led out, it is divided into two paths: one path is connected to the ammonia water cooler 14 through the first gas discharge pipeline 108 to form a first-stage flash gas extraction pipeline; the other path is connected to the second ammonia water pre-cooler 10 for standby second-stage flash through the second gas discharge pipeline 109. The rich ammonia water vapor outlet of the second ammonia water separation tank 11 for standby second-stage flash is connected to the ammonia water cooler 14 through the third gas discharge pipeline 110 to form a standby second-stage flash gas extraction pipeline; the ammonia water cooler 14 is connected to the outside of the boundary through the dilute ammonia water discharge pipeline 111. Under normal design conditions, the standby second-stage flash gas extraction pipeline is closed, and the rich ammonia water vapor in the first ammonia water separation tank 9 directly obtains qualified ammonia water meeting the standards through the first-stage flash gas extraction pipeline; when deviating from the design conditions, the standby second-stage flash gas extraction pipeline is opened. At this time, the first-stage flash gas extraction pipeline and the standby second-stage flash gas extraction pipeline are used jointly. A part of the rich ammonia water vapor in the first ammonia water separation tank 9 is extracted by the first-stage flash gas extraction pipeline, and another part of the rich ammonia water vapor is extracted by the standby second-stage flash gas extraction pipeline, ensuring the purity of the ammonia water. An on-line analyzer is provided on the first-stage flash rich ammonia water vapor extraction pipeline 116, which can sample and control the rich ammonia water vapor separated by the first ammonia water separation tank 9 in real time. According to the analysis results of the sampling, the opening and closing of the standby second-stage flash are controlled to achieve stage change control. Control valves are respectively provided on the first gas discharge pipeline 108 and the second gas discharge pipeline 109, and are in cascade control with the on-line analyzer; both the first gas discharge pipeline 108 and the third gas discharge pipeline 110 can obtain rich ammonia water vapor with >20%wt and are both connected to the inlet pipeline of the ammonia water cooler 14.
[0031] The cooling condensate outlet of the ammonia water separation tank 9 for the first-stage flash evaporation is connected to the condensate cooler 12. The condensate cooler 12 is connected back to the buffer tank 1 through the first return pipeline 117. The cooling condensate outlet of the ammonia water separation tank 11 for the standby second-stage flash evaporation is connected to the condensate cooler 13. The condensate cooler 13 is connected back to the buffer tank 1 through the second return pipeline 118. The condensate of the ammonia water separation tank 9 and the ammonia water separation tank 11 returns to the buffer tank 1 for recycling after being cooled by the condensate cooler.
[0032] The gas outlet at the top of the ammonia distillation column 4 is connected to the scrubbing tower 15 through the acid gas discharge pipeline 112. The waste gas outlet of the scrubbing tower 15 is connected to the outside of the boundary (flare or gasifier) through the waste gas discharge pipeline 113. The washing liquid outlet of the scrubbing tower 15 is connected to the buffer tank 1 for recycling through the washing liquid discharge pipeline 114. The acid gas extraction temperature of the acid gas discharge pipeline 112 is controlled at 95 - 100 °C. The extraction temperature is higher than the crystallization temperature of ammonia to avoid crystallization and prevent blockage of equipment and pipelines. The ammonia entrained by the acid gas is removed by the scrubbing tower 15 and then returns to the buffer tank 1 for recycling, avoiding ammonia loss and ensuring the separation efficiency and recovery of ammonia. A steam condensate inlet is provided on the scrubbing tower 15. The steam condensate inlet is connected to the high-temperature condensate discharge pipeline of the reboiler 5 through the steam condensate feed pipeline 115. When the scrubbing tower 15 is blocked, the high-temperature condensate discharged from the reboiler 5 can be introduced into the scrubbing tower 15 through the steam condensate feed pipeline 115 to eliminate the blockage through the high-temperature condensate. Temperature and pressure detection equipment is provided at the upper part of the scrubbing tower 15 to judge whether there is blockage. A regulating valve is provided on the steam condensate feed pipeline 115 to ensure the normal operation of the scrubbing tower.
[0033] The waste water outlet pipeline at the bottom of the ammonia distillation column 4 is connected to the hot side of the rich and lean liquid heat exchanger 6 and the bottom cooler 7, and then is divided into two paths: one path is connected to the washing water inlet of the scrubbing tower 15 through the washing water feed pipeline 106, and the other path is connected to the waste water out of the boundary through the qualified waste water discharge pipeline 107. Part of the waste water discharged from the ammonia distillation column 4 is introduced into the scrubbing tower 15 as washing water, saving the use of additional washing water, reducing costs and improving economic benefits.
[0034] The ammonia distillation column 4 adopts a combination of trays 41 and packing 42. Trays 41 are arranged at the parts corresponding to the side line extraction outlets inside the tower, and the rest of the tower uses packing 42, which is beneficial to reducing the overall height of the tower and the investment cost of the ammonia distillation column while ensuring the separation efficiency of the tower.
[0035] Example 1 of ammonia recovery:
[0036] In this embodiment, the standby secondary flash evaporation is closed, and ammonia water is obtained by using primary flash evaporation. The operating pressure of the ammonia distillation tower 4 is 0.3 Mpag, the ammonia nitrogen content of the feed of the coal gas condensate is 0.15% wt, the operating temperature at the top of the ammonia distillation tower 4 is 95 °C, and the operating temperature at the bottom of the ammonia distillation tower 4 is 145 °C; the ammonia in the wastewater at the bottom of the ammonia distillation tower 4 is < 50 mg / L, the ammonia in the waste gas at the top of the ammonia distillation tower 4 is ~800 PPm, the operating pressure of the scrubbing tower 15 is 0.05 Mpag, the operating temperature at the top of the scrubbing tower 15 is ~45 °C, the temperature of the scrubbing water is 40 °C, and the ammonia in the waste gas at the top of the scrubbing tower 15 is 50 PPm; the side-line extraction temperature of the ammonia distillation tower 4 is 143 °C, the primary flash evaporation pressure is 0.25 Mpag, and the temperature of the primary flash evaporation is 132 °C, obtaining ammonia water with a concentration of 21.5 wt%.
[0037] Second embodiment of ammonia recovery:
[0038] In this embodiment, the standby secondary flash evaporation is turned on, and ammonia water is obtained by combining primary flash evaporation + standby secondary flash evaporation. The operating pressure of the ammonia distillation tower 4 is 0.4 Mpag, the ammonia nitrogen content of the feed of the coal gas condensate is 0.2% wt, the operating temperature at the top of the ammonia distillation tower 4 is 98 °C, and the operating temperature at the bottom of the ammonia distillation tower 4 is 153 °C; the ammonia in the wastewater at the bottom of the ammonia distillation tower 4 is < 50 mg / L, the ammonia in the waste gas at the top of the ammonia distillation tower 4 is ~1000 PPm, the operating pressure of the scrubbing tower 15 is 0.04 Mpag, the operating temperature at the top of the scrubbing tower 15 is ~43 °C, the temperature of the scrubbing water is 40 °C, and the ammonia in the waste gas at the top of the scrubbing tower 15 is < 80 PPm; the side-line extraction temperature of the ammonia distillation tower 4 is 152 °C, the primary flash evaporation pressure is 0.35 Mpag, and the temperature of the primary flash evaporation is 138 °C, obtaining ammonia water with a concentration of 11.5 wt%, the secondary flash evaporation pressure is 0.3 Mpag, and the temperature of the secondary flash evaporation is 118 °C, obtaining ammonia water with a concentration of 28 wt%, and the combination of primary flash evaporation + secondary flash evaporation obtains ammonia water with a concentration of > 20 wt%.
[0039] The above description is an explanation of the present invention, not a limitation thereof. Without departing from the spirit of the present invention, the present invention can be modified in any form.
Claims
1. An ammonia recovery system for low-sulfur coal gas condensate, comprising an ammonia distillation tower (4), a primary flash distillation, a standby secondary flash distillation, and an ammonia water cooler (14), wherein the primary flash distillation includes a first ammonia water precooler (8) and a first ammonia water separation tank (9) connected thereto, and the standby secondary flash distillation includes a second ammonia water precooler (10) and a second ammonia water separation tank (11) connected thereto, characterized in that: The side line extraction outlet of the ammonia distillation tower (4) is connected to the hot side of the ammonia precooler (8), the ammonia-rich water vapor outlet of the ammonia separation tank (9) is connected to the primary flash ammonia-rich water vapor extraction pipeline (116), the primary flash ammonia-rich water vapor extraction pipeline (116) is connected to the ammonia cooler (14) through the first gas discharge pipeline (108), the primary flash ammonia-rich water vapor extraction pipeline (116) is connected to the standby secondary flash ammonia precooler (10) through the second gas discharge pipeline (109), the standby secondary flash ammonia separation tank (10) is connected to the standby secondary flash ammonia precooler (10) through the second gas discharge pipeline (109). The ammonia-rich water vapor outlet of the ammonia distillation tower (11) is connected to the ammonia water cooler (14) through the third gas outlet pipeline (110), and the ammonia water cooler (14) is connected to the dilute ammonia water outlet area through the dilute ammonia water outlet pipeline (111); under normal design conditions, the spare secondary flash gas production pipeline is closed; when the design conditions are deviated, the spare secondary flash gas production pipeline is opened; the wastewater outlet pipeline at the bottom of the ammonia distillation tower (4) is connected to the hot side of the lean-rich liquid heat exchanger (6) and the tower bottom cooler (7), and then connected to the wastewater outlet area through the qualified wastewater discharge pipeline (107).
2. The ammonia recovery system for low-sulfur coal gas condensate according to claim 1, characterized in that: An online analyzer is provided on the first-stage flash ammonia-rich water vapor extraction pipeline (116), and regulating valves are provided on the first gas discharge pipeline (108) and the second gas discharge pipeline (109) respectively, which are controlled in cascade with the online analyzer; the opening and closing of the standby second-stage flash is controlled according to the analysis results of the sampling.
3. The ammonia recovery system for low-sulfur coal gas condensate according to claim 1, characterized in that: The first-stage flash ammonia-rich water vapor extraction pipeline (116) is connected to the first gas discharge pipeline (108) and the second gas discharge pipeline (109) respectively; the first gas discharge pipeline (108) and the third gas discharge pipeline (110) are both connected to the inlet pipeline of the ammonia water cooler (14).
4. The ammonia recovery system for low-sulfur coal gas condensate according to claim 1, characterized in that: A buffer tank (1) and a feed pump (2) are provided before the ammonia distillation tower (4). The buffer tank (1) is connected to a condensate pipeline (101), and the liquid outlet of the buffer tank (1) is connected to the feed pump (2). The feed pump (2) is connected to the top of the ammonia distillation tower (4) through a condensate cold feed pipeline (104); the feed pump (2) is connected to the cold side of an ammonia precooler (8) and the cold side of a lean-rich liquid heat exchanger (6) in sequence through a condensate hot feed pipeline (105), and then connected to the middle of the ammonia distillation tower (4).
5. The ammonia recovery system for low-sulfur coal gas condensate according to claim 4, characterized in that: A filter (3) is also provided before the ammonia distillation tower (4); the feed pump (2) is connected to the filter (3) via a filter feed pipeline (102); and the filter (3) is connected back to the buffer tank (1) via a filter discharge pipeline (103).
6. The ammonia recovery system for low-sulfur coal gas condensate according to claim 1, characterized in that: The cooling condensate outlet of the ammonia separation tank (9) is connected to the condensate cooler (12), and the condensate cooler (12) is connected back to the buffer tank (1) through a first return pipeline (117); the cooling condensate outlet of the ammonia separation tank (11) is connected to the condensate cooler (13), and the condensate cooler (13) is connected back to the buffer tank (1) through a second return pipeline (118).
7. The ammonia recovery system for low-sulfur coal gas condensate according to claim 1, characterized in that: The gas outlet of the ammonia distillation tower (4) is connected to the washing tower (15) via the acid gas discharge pipeline (112), the waste gas outlet of the washing tower (15) is connected to the outside via the waste gas discharge pipeline (113), and the washing liquid outlet of the washing tower (15) is connected to the buffer tank (1) via the washing liquid discharge pipeline (114); the acid gas extraction temperature of the acid gas discharge pipeline (112) is controlled at 95 to 100°C.
8. The ammonia recovery system for low-sulfur coal gas condensate according to claim 7, characterized in that: The washing water inlet of the washing tower (15) is connected to the waste water outlet pipeline of the ammonia distillation tower (4) through the washing water feed pipeline (106); and temperature and pressure detection equipment is arranged on the upper part of the washing tower (15).
9. The ammonia recovery system for low-sulfur coal gas condensate according to claim 1, characterized in that: The bottom of the ammonia distillation tower (4) is connected to a reboiler (5), and a heat source is provided by the reboiler (5); a steam condensate inlet is provided on the washing tower (15), and the steam condensate inlet is connected to a high-temperature condensate discharge pipeline of the reboiler (5) through a steam condensate feed pipeline (115), and a regulating valve is provided on the steam condensate feed pipeline (115).
10. The ammonia recovery system for low-sulfur coal gas condensate according to claim 1, characterized in that: A tower plate (41) is provided at a position corresponding to the side line production outlet in the ammonia distillation tower (4), and fillers (42) are used in the remaining part of the tower.