Method and device for online sedimentation and oil removal of ammonia distillation wastewater

Abstract

The invention relates to a method and a device for online sedimentation and oil removal of ammonia distillation wastewater, the ammonia distillation wastewater from an ammonia distillation tower in a production state enters a wastewater storage tank of an ammonia distillation tower in a standby state through an ammonia distillation wastewater pipeline, and tar asphalt substances in the ammonia distillation wastewater in the wastewater storage tank of the ammonia distillation tower in the standby state are settled and purified; and the ammonia distillation wastewater without most tar asphalt substances is sent out. The method has the advantage that the ammonia distillation wastewater can be further purified. Funds for newly building external ammonia distillation wastewater purification equipment are saved, and meanwhile, the problem that no building position exists is solved. The volume of the bottom tank of the spare ammonia distillation tower is utilized to realize effective purification of ammonia distillation wastewater, the investment is low, and the effect is quick.

Description

Technical Field

[0001] The invention belongs to the field of ammonia evaporation wastewater treatment, and in particular relates to a method and a device for online sedimentation and oil removal of ammonia evaporation wastewater. Background Art

[0002] The ammonia distillation tower is an important distillation equipment in the process of treating residual ammonia water in the coal gas purification process. As the coke oven enters the end of its life, the impurities in the circulating ammonia water increase, and the originally pure circulating ammonia water becomes turbid. The original purification device can no longer meet the requirements of purifying the residual ammonia water. The residual ammonia water after ammonia distillation contains a certain amount of tar asphalt and other substances, which leads to frequent blockages in the wastewater heat exchanger, wastewater cooler and wastewater pipeline, bringing huge pressure to environmental protection.

[0003] In the prior art, patent application number: CN202310765300.8 discloses a device for treating ammonia evaporation wastewater, which drives the filter plate on its outer wall to rotate through a rotating shaft. Under the action of filter plates at different positions, the wastewater can be dispersed, so that the PAC agent, demulsifier and PAM agent in the filter plate can be fully diffused, and the toxic substances and tar substances in the wastewater can be fully mixed, so as to achieve the treatment of ammonia evaporation wastewater, avoid the accumulation of tar substances at the bottom of the ammonia evaporation tower during long-term continuous operation of the ammonia evaporation tower, and facilitate the operation of the ammonia evaporation system. Patent application number: 201811490468.8 discloses a method for removing oil from ammonia evaporation wastewater, wherein the oil-containing ammonia evaporation wastewater is sent to an adsorption tower filled with an adsorbent, wherein the adsorbent is a molecular sieve adsorbent; the purified water is sent to a water storage tank, and a part of it is reused as cooling water. The above technical solutions all increase wastewater treatment equipment, and the transformation cost is relatively high. Through on-site experiments on ammonia evaporation wastewater, it was found that tar asphalt in ammonia evaporation wastewater will precipitate quickly, so this problem can be solved by increasing the sedimentation time of ammonia evaporation wastewater. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method and device for online sedimentation and oil removal of ammonia evaporation wastewater, which utilizes the volume of the bottom tank of the ammonia evaporation tower to effectively purify the ammonia evaporation wastewater, realize online sedimentation and oil removal of ammonia evaporation wastewater, and solve or alleviate the blockage problem of oil in ammonia evaporation wastewater.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A method for online sedimentation and oil removal of ammonia evaporation wastewater, wherein the ammonia evaporation wastewater from an ammonia evaporation tower in production state enters the wastewater storage tank of the ammonia evaporation tower in standby state through an ammonia evaporation wastewater pipeline, and the tar asphalt substances in the ammonia evaporation wastewater are precipitated in the wastewater storage tank of the ammonia evaporation tower in the standby state, the ammonia evaporation wastewater is purified, and the ammonia evaporation wastewater with most of the tar asphalt substances removed is sent out.

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

[0008] 1) Ammonia still tower 1 and ammonia still tower 2 are standby for each other. During normal production, when ammonia still tower 1 is in production and ammonia still tower 2 is on standby, ammonia still tower 2 is in hot standby state, the ammonia outlet valve at the top of the tower is fully open, and the top pressures of ammonia still tower 1 and ammonia still tower 2 are the same;

[0009] 2) The ammonia evaporation wastewater from the ammonia evaporation tower 1 enters the wastewater storage tank at the bottom of the ammonia evaporation tower 2 through the wastewater outlet of the ammonia evaporation tower 2, and enters from the bottom of the wastewater storage tank, and the tar asphalt material settles naturally;

[0010] 3) The settled ammonia wastewater enters the ammonia wastewater pump through the outlet of the wastewater sedimentation pipeline of the ammonia distillation tower 2, and is sent out through the outlet pipeline after being pressurized; the settled tar asphalt material enters the tar pit through the tar asphalt pipeline at the bottom of the wastewater storage tank.

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

[0012] A device for online sedimentation and oil removal of ammonia distillation wastewater comprises an ammonia distillation tower 1, an ammonia distillation tower 2, an ammonia distillation wastewater pump, an outlet pipe, a pipe after wastewater sedimentation, and a connecting pipe; the ammonia distillation wastewater outlet of the ammonia distillation tower 1 is connected to the ammonia distillation wastewater outlet of the ammonia distillation tower 2 through a connecting pipe, the connecting pipe is connected to the inlet of the ammonia distillation wastewater pump, and the outlet of the ammonia distillation wastewater pump is connected to the outlet pipe; both ends of the pipe after wastewater sedimentation are connected to the wastewater storage tanks of the ammonia distillation tower 1 and the ammonia distillation tower 2, and the pipe after wastewater sedimentation is connected to the connecting pipe.

[0013] The ammonia evaporation wastewater outlet of the ammonia evaporation tower 1 is arranged at the lower part of the wastewater storage tank of the ammonia evaporation tower 1; the ammonia evaporation wastewater outlet of the ammonia evaporation tower 2 is arranged at the lower part of the wastewater storage tank of the ammonia evaporation tower 2.

[0014] It also includes a tar discharge pipeline and a tar discharge pit. The tar asphalt discharge pipeline is connected to the tar discharge pit; the tar asphalt discharge pipeline is connected to the bottom of the wastewater storage tank of the first ammonia distillation tower and the second ammonia distillation tower.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention further allows the ammonia evaporation wastewater to undergo natural sedimentation and static oil removal in the wastewater storage tank of the standby ammonia evaporation tower, thereby removing most of the tar asphalt in the ammonia evaporation wastewater, and the ammonia evaporation wastewater is further purified.

[0017] 2. The present invention saves the funds needed to construct an external ammonia wastewater purification device, and also solves the problem of lack of construction space.

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

[0019] 4. The high-temperature ammonia evaporation wastewater has a certain amount of pressure reduction in the standby ammonia evaporation tower (P1 底 -P1 顶 ), part of the ammonia wastewater can be evaporated, and after being condensed and cooled by circulating water at the top of the tower, it enters the ammonia wastewater, which can reduce the temperature of the ammonia wastewater. Continuing to reduce the temperature of the ammonia wastewater in summer is beneficial to the indicators of environmental protection wastewater biochemistry.

[0020] 5. The present invention utilizes the wastewater storage tank volume of the spare ammonia distillation tower to perform online sedimentation and oil removal on the ammonia distillation wastewater, which can reduce the temperature of the ammonia distillation wastewater and solve or delay the blockage problem of the ammonia distillation wastewater on subsequent equipment and pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 It is a structural diagram of the connecting pipeline.

[0023] In the figure: 1- ammonia distillation tower 1 2- ammonia distillation tower 2 3- fractionator 4- ammonia gas outlet 5- residual ammonia water inlet 6- steam inlet 7- circulating water inlet 8- circulating water outlet 9- ammonia distillation wastewater outlet of ammonia distillation tower 1 10- ammonia distillation wastewater outlet of ammonia distillation tower 2 11- tar pit 12- pipeline after wastewater sedimentation 13- ammonia distillation wastewater pump 14- outlet pipeline 15- connecting main pipe 16- connecting branch pipe. DETAILED DESCRIPTION

[0024] The present invention is described in detail below in conjunction with 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 evaporation wastewater, wherein the ammonia evaporation wastewater from the ammonia evaporation tower 1 enters the wastewater storage tank of the ammonia evaporation tower 2 through the ammonia evaporation wastewater pipeline, the tar asphalt material in the ammonia evaporation wastewater is precipitated and purified at the bottom of the wastewater storage tank of the ammonia evaporation tower 2, and the ammonia evaporation wastewater with most of the tar asphalt material removed is sent out, so as to achieve online purification, sedimentation and oil removal of ammonia evaporation wastewater.

[0026] A device for online sedimentation and oil removal of ammonia distillation wastewater, comprising an ammonia distillation tower 1, an ammonia distillation tower 2, an ammonia distillation wastewater pump 13, an outlet pipe 14, a pipe 12 after wastewater sedimentation, and a connecting pipe; the ammonia distillation wastewater outlet 9 of the ammonia distillation tower 1 is connected to the ammonia distillation wastewater outlet 10 of the ammonia distillation tower 2 through a connecting pipe, the connecting pipe is connected to the inlet of the ammonia distillation wastewater pump 13, and the outlet of the ammonia distillation wastewater pump 13 is connected to the outlet pipe 14; both ends of the pipe 12 after wastewater sedimentation are connected to the wastewater storage tanks of the ammonia distillation tower 1 and the ammonia distillation tower 2, and the pipe 12 after wastewater sedimentation is connected to the connecting pipe.

[0027] The ammonia evaporation wastewater pump 13 can be one working and one standby, and the connecting pipeline is composed 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 a valve is used for the ammonia evaporation wastewater outlet 9 of the ammonia evaporation tower 1 and the ammonia evaporation wastewater outlet 10 of the ammonia evaporation tower 2; valves are connected to both connecting branch pipes 16, and the two ends of the connecting branch pipe 16 are respectively connected to the connecting main pipe 15 without a valve and the ammonia evaporation wastewater pump 13, and the two ends of the connecting main pipe 15 connected with a valve are connected to the connecting branch pipe 16, and the connecting main pipe 15 connected with a valve is connected to the pipeline 12 after the wastewater sedimentation.

[0028] The ammonia evaporation wastewater outlet 9 of the ammonia evaporation tower 1 is arranged at the lower part of the wastewater storage tank of the ammonia evaporation tower 1; the ammonia evaporation wastewater outlet 10 of the ammonia evaporation tower 2 is arranged at the lower part of the wastewater storage tank of the ammonia evaporation tower 2. The ammonia outlet 4 pipelines at the tops of the ammonia evaporation tower 1 and the ammonia evaporation tower 2 are connected to each other. The dividers 3 at the tops of the ammonia evaporation tower 1 and the ammonia evaporation tower 2 are connected to each other, the circulating water inlets 7 of the two are connected to each other, and the circulating water outlets 8 of the two are connected to each other. The residual ammonia water inlet 5 is arranged at the upper part of the ammonia evaporation tower 1 and the ammonia evaporation tower 2. The steam inlet 6 is connected to the ammonia evaporation tower above the wastewater storage tank.

[0029] The device for online sedimentation and oil removal of ammonia evaporation wastewater also includes a tar discharge pipeline and a tar discharge pit 11, the tar discharge pipeline is connected to the tar discharge pit 11; the tar discharge pipeline is connected to the bottom of the wastewater storage tank of ammonia evaporation tower 1 and ammonia evaporation tower 2.

[0030] A method for online sedimentation and oil removal of ammonia evaporation wastewater, comprising the following steps:

[0031] 1) Ammonia Evaporation Tower 1 and Ammonia Evaporation Tower 2 are in standby relationship with each other. During normal production, when Ammonia Evaporation Tower 1 is in production and Ammonia Evaporation Tower 2 is in standby, Ammonia Evaporation Tower 2 is in hot standby state. The wastewater storage tank space at the bottom of Ammonia Evaporation Tower 2 is used as a purification and sedimentation device for the ammonia evaporation wastewater of Ammonia Evaporation Tower 1 to achieve the purpose of purifying the ammonia evaporation wastewater. The valve of the ammonia outlet 4 at the top of the tower is fully open, and the top pressures of Ammonia Evaporation Tower 1 and Ammonia Evaporation Tower 2 are the same, that is, P1 顶 =P2 顶 .

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

[0033] 2) The ammonia evaporation wastewater from the ammonia evaporation tower 1 enters the wastewater storage tank at the bottom of the ammonia evaporation tower 2 through the wastewater outlet of the ammonia evaporation tower 2, and enters from the bottom of the wastewater storage tank, and the tar asphalt material settles naturally by gravity;

[0034] 3) The settled ammonia wastewater enters the ammonia wastewater pump 13 through the outlet of the pipe 12 after the wastewater sedimentation of the ammonia still 2, and is sent out through the outlet pipe 14 after being pressurized, which can be recycled. The outlet pipe 14 sends it to the ammonia wastewater heat exchanger, and then it is sent to the sewage treatment device after being cooled by the wastewater cooler. The settled tar asphalt material regularly enters the tar pit 11 through the tar discharge pipe at the bottom of the wastewater storage tank. The tar asphalt is regularly removed to maintain the normal operation of the ammonia still.

[0035] Sedimentation time = (liquid level difference h between the wastewater storage tanks of ammonia distillation tower 1 and ammonia distillation tower 2 + liquid level of the wastewater storage tank of ammonia distillation tower 1) * cross-sectional area of ​​the wastewater storage tank of ammonia distillation tower 2 / ammonia distillation wastewater flow rate.

[0036] The actual measured online ammonia tower top pressure is 23kPa, the ammonia tower bottom pressure is 33kPa, the ammonia tower liquid level is 1.5 meters, the ammonia tower diameter is 2.8 meters, and the wastewater volume is 80m 3 / h, the wastewater density is calculated as 1. By calculating the pressure above the liquid surface at the bottom of the standby ammonia distillation tower, P 底 =(33-23)=10kPa, equivalent to h=1 meter. The additional purification time of ammonia wastewater is 3.14*1.4*1.4*(1+1.5) / 80=16 minutes.

[0037] The present invention further allows the ammonia evaporation wastewater to undergo natural sedimentation and static oil removal in a wastewater storage tank of a standby ammonia evaporation tower, thereby removing most of the tar asphalt in the ammonia evaporation wastewater, further purifying the ammonia evaporation wastewater, requiring little investment and achieving quick results, thereby saving funds for the construction of additional external ammonia evaporation wastewater purification equipment.

[0038] Through the above specific implementation, the technical personnel in the relevant technical field can easily implement the present invention. However, it should be understood that the present invention is not limited to the above specific implementation. On the basis of the disclosed implementation, the technical personnel in the relevant technical field can arbitrarily combine different technical features to achieve different technical solutions. Due to the limited space and to make the specification concise, the various solutions composed of these combinations are not described one by one. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for online sedimentation and oil removal of ammonia wastewater, characterized in that: The ammonia evaporation wastewater from the ammonia evaporation tower in the production state enters the wastewater storage tank of the ammonia evaporation tower in the standby state through the ammonia evaporation wastewater pipeline. The tar asphalt substances in the ammonia evaporation wastewater are precipitated in the wastewater storage tank of the ammonia evaporation tower in the standby state, and the ammonia evaporation wastewater is purified and sent out with most of the tar asphalt substances removed.

2. The method for online sedimentation and oil removal of ammonia wastewater according to claim 1, characterized in that: The following steps are involved: 1) Ammonia still tower 1 and ammonia still tower 2 are standby for each other. During normal production, when ammonia still tower 1 is in production and ammonia still tower 2 is on standby, ammonia still tower 2 is in hot standby state, the ammonia outlet valve at the top of the tower is fully open, and the top pressures of ammonia still tower 1 and ammonia still tower 2 are the same; 2) The ammonia evaporation wastewater from the ammonia evaporation tower 1 enters the wastewater storage tank at the bottom of the ammonia evaporation tower 2 through the wastewater outlet of the ammonia evaporation tower 2, and enters from the bottom of the wastewater storage tank, and the tar asphalt material settles naturally; 3) The settled ammonia wastewater enters the ammonia wastewater pump through the outlet of the wastewater sedimentation pipeline of the ammonia distillation tower 2, and is sent out through the outlet pipeline after being pressurized; the settled tar asphalt material enters the tar pit through the tar asphalt pipeline at the bottom of the wastewater storage tank.

3. The method for online sedimentation and oil removal of ammonia wastewater according to claim 2, characterized in that: The top pressure of the ammonia still tower 1 is 15-30 kPa, the bottom pressure is 20-45 kPa, the top temperature is 101-103°C, the bottom temperature is 101-106°C, and the liquid level is 0.5-2m; the top pressure of the ammonia still tower 2 is 15-25 kPa, the bottom pressure is 15-25 kPa, the top temperature is 98-100°C, the bottom temperature is 98-102°C, and the liquid level is 2-4m.

4. A device used in the method for online sedimentation and oil removal of ammonia wastewater according to any one of claims 1 to 3, characterized in that: It includes an ammonia distillation tower 1, an ammonia distillation tower 2, an ammonia distillation wastewater pump, an outlet pipe, a pipe after wastewater sedimentation, and a connecting pipe; the ammonia distillation wastewater outlet of the ammonia distillation tower 1 is connected to the ammonia distillation wastewater outlet of the ammonia distillation tower 2 through a connecting pipe, the connecting pipe is connected to the inlet of the ammonia distillation wastewater pump, and the outlet of the ammonia distillation wastewater pump is connected to the outlet pipe; both ends of the pipe after wastewater sedimentation are connected to the wastewater storage tanks of the ammonia distillation tower 1 and the ammonia distillation tower 2, and the pipe after wastewater sedimentation is connected to the connecting pipe.

5. The device for online sedimentation and oil removal of ammonia wastewater according to claim 4, characterized in that: The ammonia evaporation wastewater outlet of the ammonia evaporation tower 1 is arranged at the lower part of the wastewater storage tank of the ammonia evaporation tower 1; the ammonia evaporation wastewater outlet of the ammonia evaporation tower 2 is arranged at the lower part of the wastewater storage tank of the ammonia evaporation tower 2.

6. The device for online sedimentation and oil removal of ammonia wastewater according to claim 4, characterized in that: It also includes a tar discharge pipeline and a tar discharge pit. The tar asphalt discharge pipeline is connected to the tar discharge pit; the tar asphalt discharge pipeline is connected to the bottom of the wastewater storage tank of the first and second ammonia distillation towers.

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