Method and device for on-line oil removal from ammonia distillation wastewater

Abstract

The present application relates to a kind of ammonia distillation wastewater online sedimentation oil removal method and device, from the ammonia distillation tower of production state ammonia distillation wastewater is entered into the wastewater storage tank of standby state ammonia distillation tower by ammonia distillation wastewater pipeline, tar pitch material in ammonia distillation wastewater in the wastewater storage tank of standby state ammonia distillation tower is settled to obtain purification, and send out the ammonia distillation wastewater of most tar pitch material removal.The advantage is: ammonia distillation wastewater can be further purified.Saved the need to increase the construction of external ammonia distillation wastewater purification equipment funds, also solves the problem of no construction location.Using the volume of spare ammonia distillation tower bottom tank realizes the effective purification of ammonia distillation wastewater, less investment, quick effect.

Description

Technical Field

[0001] This invention belongs to the field of ammonia-containing wastewater treatment, and particularly relates to a method and apparatus for online sedimentation and oil removal from ammonia-containing wastewater. Background Technology

[0002] The ammonia stripping tower is an important distillation device in the process of treating residual ammonia water in the coal gas purification process. As the coke oven enters the end of its service life, the impurities in the circulating ammonia water increase, and the originally pure circulating ammonia water becomes more turbid. The original purification device can no longer meet the requirements for purifying the residual ammonia water. After ammonia stripping, the residual ammonia water contains a certain amount of tar pitch and other substances, which causes frequent blockages in the wastewater heat exchanger, wastewater cooler and wastewater pipes, putting great pressure on environmental protection.

[0003] In the prior art, patent application number CN202310765300.8 discloses an ammonia stripping wastewater treatment device. A rotating shaft drives the filter plates on its outer wall to rotate. Under the action of the filter plates at different positions, the wastewater is dispersed, allowing the PAC, demulsifier, and PAM agents in the filter plates to fully diffuse and mix with toxic substances and tar-like substances in the wastewater. This achieves the treatment of ammonia stripping wastewater and prevents tar-like substances from accumulating at the bottom of the ammonia stripping tower during long-term continuous operation, thus benefiting the operation of the ammonia stripping system. Patent application number 201811490468.8 discloses a method for removing oil from ammonia stripping wastewater. The oily ammonia stripping wastewater is fed into an adsorption tower filled with an adsorbent, wherein the adsorbent is a molecular sieve adsorbent; the purified water is sent to a storage tank, and a portion is reused as cooling water. Both of the above technical solutions involve adding wastewater treatment equipment, resulting in high modification costs. On-site experiments on ammonia-containing wastewater revealed that tar pitch in the wastewater settles quickly, so this problem can be solved by increasing the settling time of the ammonia-containing wastewater. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a method and apparatus for online sedimentation and oil removal of ammonia stripping wastewater. This method utilizes the volume of the bottom tank of the ammonia stripping tower to effectively purify the ammonia stripping wastewater, achieves online sedimentation and oil removal of the ammonia stripping wastewater, and solves or mitigates the clogging problem caused by oil in the ammonia stripping wastewater.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for online sedimentation and oil removal of ammonia stripping wastewater involves the ammonia stripping wastewater from the production ammonia stripping tower entering the wastewater storage tank of the standby ammonia stripping tower through an ammonia stripping wastewater pipeline. In the wastewater storage tank of the standby ammonia stripping tower, tar and asphalt substances in the ammonia stripping wastewater settle, thus purifying the ammonia stripping wastewater. The purified ammonia stripping wastewater is then discharged, with most of the tar and asphalt substances removed.

[0007] The method for online sedimentation and oil removal of ammonia-containing wastewater includes the following steps:

[0008] 1) Ammonia stripping tower 1 and ammonia stripping tower 2 are backups for each other. During normal production, when ammonia stripping tower 1 is producing and ammonia stripping tower 2 is on standby, ammonia stripping tower 2 is in hot standby mode, with the ammonia outlet valve at the top of the tower fully open, and the top pressure of ammonia stripping tower 1 and ammonia stripping tower 2 is the same.

[0009] 2) The ammonia stripping wastewater from ammonia stripping tower one enters the wastewater storage tank at the bottom of ammonia stripping tower two through the wastewater outlet of ammonia stripping tower two. The tar and pitch substances naturally settle as they enter from the bottom of the wastewater storage tank.

[0010] 3) The settled ammonia stripping wastewater enters the ammonia stripping wastewater pump through the outlet of the wastewater sedimentation pipeline of the second ammonia stripping tower, and is then pressurized and sent out through the outlet pipeline; the settled tar and pitch substances enter the tar discharge pit through the tar and pitch discharge pipeline at the bottom of the wastewater storage tank.

[0011] The ammonia stripping tower 1 has a top pressure of 15-30 kPa, a bottom pressure of 20-45 kPa, a top temperature of 101-103℃, a bottom temperature of 101-106℃, and a liquid level of 0.5-2 m; the ammonia stripping tower 2 has a top pressure of 15-25 kPa, a bottom pressure of 15-25 kPa, a top temperature of 98-100℃, a bottom temperature of 98-102℃, and a liquid level of 2-4 m.

[0012] An online sedimentation and oil removal device for ammonia stripping wastewater includes an ammonia stripping tower 1, an ammonia stripping tower 2, an ammonia stripping wastewater pump, an outlet pipe, a wastewater sedimentation pipe, and a connecting pipe. The ammonia stripping wastewater outlet of the ammonia stripping tower 1 is connected to the ammonia stripping wastewater outlet of the ammonia stripping tower 2 via the connecting pipe. The connecting pipe is connected to the inlet of the ammonia stripping wastewater pump, and the outlet of the ammonia stripping wastewater pump is connected to the outlet pipe. The two ends of the wastewater sedimentation pipe are connected to the wastewater storage tanks of the ammonia stripping tower 1 and the ammonia stripping tower 2, and the wastewater sedimentation pipe is connected to the connecting pipe.

[0013] The ammonia stripping tower one's ammonia stripping wastewater outlet is located at the bottom of the ammonia stripping tower one's wastewater storage tank; the ammonia stripping tower two's ammonia stripping wastewater outlet is located at the bottom of the ammonia stripping tower two's wastewater storage tank.

[0014] It also includes tar discharge pipelines and tar discharge pits, with tar pitch discharge pipelines connected to the tar discharge pits; and tar pitch discharge pipelines connected to the bottom of the wastewater storage tanks of ammonia stripping tower one and ammonia stripping tower two.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. This invention removes most of the tar and pitch from the ammonia stripping wastewater by allowing it to undergo further natural sedimentation and static oil removal in the wastewater storage tank of the standby ammonia stripping tower, thus further purifying the ammonia stripping wastewater.

[0017] 2. This invention saves the funds required to construct additional external ammonia-eating wastewater purification equipment, and also solves the problem of not having a suitable location for construction.

[0018] 3. This invention ingeniously utilizes the volume of the bottom tank of the ammonia stripping tower to achieve effective purification of ammonia stripping wastewater, with low investment and quick results.

[0019] 4. The pressure of the high-temperature ammonia stripping wastewater is reduced to a certain extent in the standby ammonia stripping tower (P1). 底 -P1 顶 This method can partially evaporate ammonia-containing wastewater, cool it with circulating water at the top of the tower, and then reintroduce it into the ammonia-containing wastewater. This can lower the temperature of the ammonia-containing wastewater, and further lowering the temperature of the ammonia-containing wastewater in summer is beneficial to the biochemical indicators of environmentally friendly wastewater.

[0020] 5. This invention utilizes the wastewater storage tank volume of the spare ammonia stripping tower to perform online sedimentation and oil removal of ammonia stripping wastewater, which can reduce the temperature of ammonia stripping wastewater and solve or delay the problem of ammonia stripping wastewater clogging subsequent equipment and pipelines. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the connecting pipes.

[0023] In the diagram: 1-Ammonia stripping tower one; 2-Ammonia stripping tower two; 3-Condenser; 4-Ammonia outlet; 5-Residual ammonia water inlet; 6-Steam inlet; 7-Circulating water inlet; 8-Circulating water outlet; 9-Ammonia stripping wastewater outlet of ammonia stripping tower one; 10-Ammonia stripping wastewater outlet of ammonia stripping tower two; 11-Tar discharge pit; 12-Wastewater sedimentation pipe; 13-Ammonia stripping wastewater pump; 14-Outlet pipe; 15-Main connecting pipe; 16-Branch connecting pipe. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0025] See Figure 1 A method for online sedimentation and oil removal of ammonia stripping wastewater is disclosed. The ammonia stripping wastewater from ammonia stripping tower 1 enters the wastewater storage tank of ammonia stripping tower 2 through an ammonia stripping wastewater pipeline. At the bottom of the wastewater storage tank of ammonia stripping tower 2, tar and asphalt substances in the ammonia stripping wastewater settle and are purified. The purified ammonia stripping wastewater, with most of the tar and asphalt substances removed, is then discharged. This achieves online purification, sedimentation, and oil removal of ammonia stripping wastewater.

[0026] An online sedimentation and oil removal device for ammonia stripping wastewater includes an ammonia stripping tower 1, an ammonia stripping tower 2, an ammonia stripping wastewater pump 13, an outlet pipe 14, a wastewater sedimentation pipe 12, and a connecting pipe. The ammonia stripping wastewater outlet 9 of the ammonia stripping tower 1 is connected to the ammonia stripping wastewater outlet 10 of the ammonia stripping tower 2 via the connecting pipe. The connecting pipe is connected to the inlet of the ammonia stripping wastewater pump 13, and the outlet of the ammonia stripping wastewater pump 13 is connected to the outlet pipe 14. The two ends of the wastewater sedimentation pipe 12 are connected to the wastewater storage tanks of the ammonia stripping tower 1 and the ammonia stripping tower 2, and the wastewater sedimentation pipe 12 is connected to the connecting pipe.

[0027] The ammonia stripping wastewater pump 13 can be used as a standby unit. The connecting pipeline consists of a connecting branch pipe 16 and a connecting main pipe 15. Valves are connected to the connecting branch pipe 16 and one connecting main pipe 15. The two connecting main pipes 15 are connected in parallel. The connecting main pipe 15 without valves is used for the ammonia stripping wastewater outlet 9 of ammonia stripping tower one and the ammonia stripping wastewater outlet 10 of ammonia stripping tower two. Valves are connected to both connecting branch pipes 16. The two ends of the connecting branch pipe 16 are respectively connected to the connecting main pipe 15 without valves and the ammonia stripping wastewater pump 13. The two ends of the connecting main pipe 15 with valves are connected to the connecting branch pipe 16. The connecting main pipe 15 with valves is connected to the wastewater sedimentation pipeline 12.

[0028] The ammonia stripping wastewater outlet 9 of ammonia stripping tower 1 is located at the lower part of the wastewater storage tank of ammonia stripping tower 1; the ammonia stripping wastewater outlet 10 of ammonia stripping tower 2 is located at the lower part of the wastewater storage tank of ammonia stripping tower 2. The ammonia outlet 4 at the top of ammonia stripping tower 1 and ammonia stripping tower 2 are interconnected. The distributors 3 at the top of ammonia stripping tower 1 and ammonia stripping tower 2 are interconnected, their circulating water inlets 7 are interconnected, and their circulating water outlets 8 are interconnected. The residual ammonia water inlet 5 is located at the upper part of ammonia stripping tower 1 and ammonia stripping tower 2. The steam inlet 6 is connected to the ammonia stripping tower above the wastewater storage tank.

[0029] The online sedimentation and oil removal device for ammonia stripping wastewater also includes a tar discharge pipe and a tar discharge pit 11. The tar discharge pipe is connected to the tar discharge pit 11. The tar discharge pipe is connected to the bottom of the wastewater storage tanks of ammonia stripping tower 1 and ammonia stripping tower 2.

[0030] A method for online sedimentation and oil removal of ammonia-containing wastewater includes the following steps:

[0031] 1) Ammonia stripping tower 1 and ammonia stripping tower 2 are mutually redundant. During normal production, when ammonia stripping tower 1 is in operation and ammonia stripping tower 2 is on standby, ammonia stripping tower 2 is in a hot standby state. The wastewater storage tank at the bottom of ammonia stripping tower 2 serves as a purification and settling device for the ammonia stripping wastewater from ammonia stripping tower 1, achieving the purpose of purifying the ammonia stripping wastewater. With the ammonia outlet valve 4 at the top of the tower fully open, the pressure at the top of ammonia stripping towers 1 and 2 is the same, i.e., P1. 顶 =P2 顶 .

[0032] The pressure at the top of the ammonia stripping tower 1 is 15-30 kPa, the pressure at the bottom is 20-45 kPa, the temperature at the top is 101-103℃, the temperature at the bottom is 101-106℃, and the liquid level is 0.5-2 m. The pressure at the top of the ammonia stripping tower 2 is 15-25 kPa, the pressure at the bottom is 15-25 kPa, the temperature at the top is 98-100℃, the temperature at the bottom is 98-102℃, and the liquid level is 2-4 m.

[0033] 2) The ammonia stripping wastewater from ammonia stripping tower 1 enters the wastewater storage tank at the bottom of ammonia stripping tower 2 through the wastewater outlet of ammonia stripping tower 2. The tar and pitch substances enter from the bottom of the wastewater storage tank and settle naturally by gravity.

[0034] 3) The settled ammonia stripping wastewater enters the ammonia stripping wastewater pump 13 through the outlet of the wastewater sedimentation pipe 12 of ammonia stripping tower 2. After pressurization, it is sent out through the outlet pipe 14 for recycling. The wastewater is then sent to the ammonia wastewater heat exchanger through the outlet pipe 14, and then cooled by the wastewater cooler before being sent to the sewage treatment plant. The settled tar and pitch material periodically enters the tar discharge pit 11 through the tar discharge pipe at the bottom of the wastewater storage tank. The tar and pitch are periodically removed to maintain the normal operation of the ammonia stripping tower.

[0035] Settling time = (Level difference h between wastewater storage tanks of ammonia stripping tower 1 and ammonia stripping tower 2 + Level of wastewater storage tank of ammonia stripping tower 1) * Cross-sectional area of ​​wastewater storage tank of ammonia stripping tower 2 / Flow rate of ammonia stripping wastewater.

[0036] Actual measurements showed the following: the top pressure of the online ammonia stripping tower was 23 kPa, the bottom pressure was 33 kPa, the liquid level was 1.5 meters, the tower diameter was 2.8 meters, and the wastewater volume was 80 m³. 3 / h, wastewater density is calculated as 1. The pressure P above the bottom liquid level of the standby ammonia stripping tower is calculated. 底 = (33-23) = 10 kPa, equivalent to h = 1 meter. The time required to purify the ammonia-containing wastewater is increased to 3.14 * 1.4 * 1.4 * (1 + 1.5) / 80 = 16 minutes.

[0037] This invention removes most of the tar and pitch from ammonia stripping wastewater by allowing it to settle and become still in the wastewater storage tank of a standby ammonia stripping tower. This process further purifies the ammonia stripping wastewater, requires less investment, yields quick results, and saves the funds needed to construct additional external ammonia stripping wastewater purification equipment.

[0038] Through the above specific embodiments, those skilled in the art can easily implement the present invention. However, it should be understood that the present invention is not limited to the specific embodiments described above. Based on the disclosed embodiments, those skilled in the art can arbitrarily combine different technical features to achieve different technical solutions. Due to space limitations and for the sake of brevity, each of these combined solutions has not been described in detail. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for online sedimentation and oil removal from ammonia-containing wastewater, characterized in that, The ammonia stripping wastewater from the production ammonia stripping tower enters the wastewater storage tank of the standby ammonia stripping tower through the ammonia stripping wastewater pipeline. In the standby wastewater storage tank, the tar and pitch substances in the ammonia stripping wastewater settle, purifying the wastewater. The purified wastewater, now free of most of the tar and pitch substances, is then discharged. The specific steps include: 1) Ammonia stripping tower 1 and ammonia stripping tower 2 are backups for each other. During normal production, when ammonia stripping tower 1 is producing and ammonia stripping tower 2 is on standby, ammonia stripping tower 2 is in hot standby mode, with the ammonia outlet valve at the top of the tower fully open. The top pressures of ammonia stripping tower 1 and ammonia stripping tower 2 are the same; the bottom pressure of ammonia stripping tower 2 = the bottom pressure of ammonia stripping tower 1 - the top pressure of ammonia stripping tower 1. 2) The ammonia stripping wastewater from ammonia stripping tower one enters the wastewater storage tank at the bottom of ammonia stripping tower two through the wastewater outlet of ammonia stripping tower two. The tar and pitch substances naturally settle as they enter from the bottom of the wastewater storage tank. 3) The settled ammonia stripping wastewater enters the ammonia stripping wastewater pump through the outlet of the wastewater sedimentation pipeline of the second ammonia stripping tower, and is then pressurized and sent out through the outlet pipeline; the settled tar and pitch substances enter the tar discharge pit through the tar and pitch discharge pipeline at the bottom of the wastewater storage tank. The ammonia stripping tower 1 has a top pressure of 15~30 kPa, a bottom pressure of 20~45 kPa, a top temperature of 101~103℃, a bottom temperature of 101~106℃, and a liquid level of 0.5~2m; the ammonia stripping tower 2 has a top pressure of 15~25 kPa, a bottom pressure of 15~25 kPa, a top temperature of 98~100℃, a bottom temperature of 98~102℃, and a liquid level of 2~4m.

2. An apparatus used in the online sedimentation and oil removal method for ammonia-containing wastewater as described in claim 1, characterized in that, It includes ammonia stripping tower one, ammonia stripping tower two, an ammonia stripping wastewater pump, an outlet pipe, a wastewater sedimentation pipe, and connecting pipes; the ammonia stripping wastewater outlet of ammonia stripping tower one is connected to the ammonia stripping wastewater outlet of ammonia stripping tower two through the connecting pipe, the connecting pipe is connected to the inlet of the ammonia stripping wastewater pump, and the outlet of the ammonia stripping wastewater pump is connected to the outlet pipe; the two ends of the wastewater sedimentation pipe are connected to the wastewater storage tanks of ammonia stripping tower one and ammonia stripping tower two, and the wastewater sedimentation pipe is connected to the connecting pipe.

3. The apparatus according to claim 2, characterized in that, The ammonia stripping tower one's ammonia stripping wastewater outlet is located at the bottom of the ammonia stripping tower one's wastewater storage tank; the ammonia stripping tower two's ammonia stripping wastewater outlet is located at the bottom of the ammonia stripping tower two's wastewater storage tank.

4. The apparatus according to claim 2, characterized in that, It also includes tar discharge pipelines and tar discharge pits, with tar pitch discharge pipelines connected to the tar discharge pits; and tar pitch discharge pipelines connected to the bottom of the wastewater storage tanks of ammonia stripping tower one and ammonia stripping tower two.

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