Ammonia distillation device for coking wastewater

Abstract

The utility model provides a coking wastewater ammonia distillation device which comprises an ammonia distillation tower, and a discharge end at the bottom of the ammonia distillation tower is communicated with a slag discharge pipe; the slag discharge pipe is also sequentially connected with a sedimentation tank and a backwashing tank; the slag discharge pipe is connected with the sedimentation tank through a first valve and is connected with the steam pipeline through a second valve; the ammonia still is also connected with a residual ammonia water storage tank; the deslagging pipe comprises an inner pipe and an outer pipe, and the steam input end of the outer pipe is connected with a steam pipeline. According to the coking wastewater ammonia distillation device provided by the invention, the residue discharge pipe comprising the inner pipe and the outer pipe is arranged at the bottom of the ammonia distillation tower, the outer pipe of the residue discharge pipe is communicated with the steam pipeline, and steam supplied by the steam pipeline is utilized to heat the inner pipe of the residue discharge pipe, so that the phenomenon that the residue discharge pipe is damaged due to reduction of the temperature of wastewater when the ammonia distillation tower discharges the wastewater is prevented; the tar in the waste water is adhered to the pipeline, so that the pipeline is blocked.

Description

Technical Field

[0001] The present application relates to the technical field of coking wastewater treatment, and in particular to a coking wastewater ammonia distillation device. Background Art

[0002] The coke oven gas produced by coking undergoes the condensation and blast stage, and the ammonia nitrogen and water molecules in the gas will condense into condensed ammonia water with complex components. Part of the ammonia water is used to circulate the condensed coke oven gas, which is the circulating ammonia water, and the remaining external drainage is called residual ammonia water. The residual ammonia water contains high concentrations of ammonia nitrogen, phenols, cyanides, sulfides and organic oil substances. The ammonia nitrogen in the coking wastewater mainly comes from the nitrogen and hydrogen elements in the high-temperature carbonization process of coal to form ammonia and enter the raw coal gas. The composition content and residual amount of ammonia water are related to the external moisture content of the coal, coking conditions and gas cooling temperature.

[0003] Residual ammonia water has the characteristics of large discharge volume and complex composition. The ammonia nitrogen content is the highest in the residual ammonia water, and ammonia nitrogen exists in the form of inorganic salts and organic matter in the residual ammonia water. Due to different gas purification processes in different coking plants, the ammonia content in the wastewater is also different. The direct discharge of a large amount of ammonia will cause great harm, such as causing eutrophication of water bodies, reducing the disinfection effect of tap water, and polluting water bodies. Therefore, the residual ammonia water cannot be discharged directly. It needs to be further treated by the biochemical wastewater station after oil removal and dephenolization and ammonia evaporation before it can be discharged from the coking plant.

[0004] There are many existing methods for treating residual ammonia water, mainly including biological method, ion exchange method, catalytic oxidation method, chemical precipitation method, steam stripping method, etc. Among them, the steam stripping method is widely used because of its advantages of low investment cost and easy operation. The steam stripping method (also known as ammonia evaporation) uses water vapor as a carrier and uses the distillation method to strip the light component ammonia in the wastewater in the stripping tower, and recovers the ammonia water after condensation. The wastewater discharged from the bottom of the tower is the wastewater after ammonia evaporation. However, since the residual ammonia water contains a considerable amount of tar, it cannot be evaporated with the water vapor during the ammonia evaporation process, but will remain in the wastewater at the bottom of the tower. After these tar-containing wastewaters are heat-exchanged with steam to evaporate ammonia, they fall into the bottom of the tower and are basically not heated, which causes the temperature of these wastewaters to decrease. When discharged, the wastewater will adhere to the inner wall of the pipeline due to the decrease in temperature when passing through the pipeline, causing pipeline blockage. Utility Model Content

[0005] The present application provides a coking wastewater ammonia distillation device, which is used to solve the problem that when the ammonia distillation tower discharges wastewater, the temperature of the wastewater decreases, causing tar in the wastewater to adhere to the pipeline and cause pipeline blockage.

[0006] The present application provides a coking wastewater ammonia distillation device, comprising an ammonia distillation tower, wherein the discharge end at the bottom of the ammonia distillation tower is connected to a slag discharge pipe;

[0007] The slag discharge pipe is also connected to the sedimentation tank and the backwash tank in sequence;

[0008] The slag discharge pipe is connected to the sedimentation tank through a first valve and is connected to the steam pipeline through a second valve;

[0009] The ammonia distillation tower is also connected to the remaining ammonia water storage tank;

[0010] The slag discharge pipe comprises an inner pipe and an outer pipe, and the steam input end of the outer pipe is connected to the steam pipeline.

[0011] Optionally, a heat exchanger is also provided between the sedimentation tank and the backwash tank;

[0012] Both the sedimentation tank and the backwash tank are connected to the shell side of the heat exchanger;

[0013] The remaining ammonia water storage tank is connected to the tube side inlet of the heat exchanger, and the tube side outlet of the heat exchanger is connected to the ammonia distillation tower.

[0014] Optionally, the backwash tank is also connected to the cold drum section and the wastewater treatment device respectively.

[0015] Optionally, the wastewater treatment device comprises a nitrogen fixation tank, a Fenton oxidation tank and a biochemical treatment tank connected in series in sequence;

[0016] The nitrogen fixation tank is also connected to the sodium phosphate solution storage tank and the magnesium chloride solution storage tank respectively.

[0017] Optionally, the sedimentation tank comprises a tank body, in which a partition wall is vertically arranged, and the partition wall divides the tank body into a sedimentation area and a drainage area;

[0018] The sedimentation area is connected to the slag discharge pipe, and the liquid discharge area is connected to the backwash tank;

[0019] The sedimentation area and the drainage area are connected through an overflow trough arranged on the upper part of the partition wall.

[0020] Optionally, an interception net is obliquely arranged in the sedimentation area of ​​the sedimentation tank;

[0021] The lower side surface of the interception net is rotatably connected to the bottom of the partition wall, and the upper side surface of the interception net is connected to the upper part of the partition wall through a restraining rope.

[0022] Optionally, a wastewater spray layer, a first steam distributor and a liquid storage area are arranged from top to bottom in the ammonia still;

[0023] A second steam distributor is also arranged in the liquid storage area, and both the first steam distributor and the second steam distributor are connected to the steam pipeline.

[0024] The present application provides a coking wastewater ammonia distillation device, which provides a slag discharge pipe including an inner pipe and an outer pipe at the bottom of an ammonia distillation tower, connects the outer pipe of the slag discharge pipe with a steam pipeline, and heats the inner pipe of the slag discharge pipe with steam supplied by the steam pipeline, thereby preventing the tar in the wastewater from adhering to the pipeline and causing the adverse consequence of pipeline blockage due to the decrease in wastewater temperature when the ammonia distillation tower discharges wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A schematic diagram of a coking wastewater ammonia distillation device provided in one embodiment of the present application;

[0027] Figure 2 A schematic diagram of a coking wastewater ammonia distillation device provided in another embodiment of the present application;

[0028] Figure 3 A schematic diagram of a coking wastewater ammonia distillation device provided in another embodiment of the present application;

[0029] Figure 4 A schematic diagram of a coking wastewater ammonia distillation device provided in yet another embodiment of the present application;

[0030] Figure 5 A schematic diagram of the structure of a sedimentation tank provided in one embodiment of the present application;

[0031] Figure 6 A schematic diagram of the structure of an ammonia distillation tower provided in one embodiment of the present application.

[0032] Description of reference numerals:

[0033] 1. Ammonia distillation tower; 2. Slag discharge pipe; 3. Sedimentation tank; 4. Backwash tank; 5. Steam pipeline; 6. Residual ammonia water storage tank; 7. Heat exchanger; 8. Cold drum section; 9. Wastewater treatment device; 11. Spray layer; 12. First steam distributor; 13. Liquid storage area; 14. Second steam distributor; 21. Inner pipe; 22. Outer pipe; 31. Tank body; 32. Partition wall; 33. Overflow tank; 34. Intercepting net; 35. Restraint rope; 91. Nitrogen fixation tank; 92. Fenton oxidation tank; 93. Biochemical treatment tank; 100. First valve; 200. Second valve; 911. Sodium phosphate solution storage tank; 912. Magnesium chloride solution storage tank. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0035] The present application provides a coking wastewater ammonia distillation device, such as Figure 1 As shown, it includes an ammonia still 1, and the discharge end at the bottom of the ammonia still 1 is connected to a slag discharge pipe 2;

[0036] The slag discharge pipe 2 is also connected to the sedimentation tank 3 and the backwash tank 4 in sequence;

[0037] The slag discharge pipe 2 is connected to the sedimentation tank 3 through the first valve 100 and is connected to the steam pipeline 5 through the second valve 200;

[0038] The ammonia distillation tower 1 is also connected to the residual ammonia water storage tank 6;

[0039] The slag discharge pipe 2 includes an inner pipe 21 and an outer pipe 22 , and a steam input end of the outer pipe 22 is connected to the steam pipeline 5 .

[0040] When in use, the remaining ammonia water from the remaining ammonia water storage tank 6 enters the ammonia still 1 and sprays down from the upper part of the ammonia still 1. At the same time, the steam supplied by the steam pipeline 5 enters the ammonia still 1 and countercurrently contacts with the remaining ammonia water sprayed down, heating the remaining ammonia water and taking away the ammonia gas in the remaining ammonia water by steam. The falling ammonia water is temporarily stored at the bottom of the ammonia still 1. The ammonia gas evaporated in the ammonia still 1 is discharged from the top of the ammonia still 1 and enters the corresponding collection device.

[0041] When the amount of waste water at the bottom of the ammonia distillation tower 1 accumulates to a certain value, the waste water needs to be discharged. At this time, the second valve 200 should be opened first, and the steam supplied by the steam pipeline 5 should be used to heat the inner tube 21 of the slag discharge pipe 2 to prevent the tar in the waste water from being deposited on the inner wall of the inner tube 21 and causing the slag discharge pipe 2 to be blocked. Then the first valve 100 should be opened to discharge the waste water into the sedimentation tank 3.

[0042] The wastewater entering the sedimentation tank 3, the tar droplets and coke residue in the wastewater will gradually settle to the bottom of the tank, and the clarified wastewater on the top will be discharged and temporarily stored in the backwash tank 4 for subsequent treatment.

[0043] The present application provides a coking wastewater ammonia distillation device, wherein a slag discharge pipe 2 including an inner pipe 21 and an outer pipe 22 is arranged at the bottom of an ammonia distillation tower 1, and the outer pipe 22 of the slag discharge pipe 2 is connected to a steam pipeline 5, and the inner pipe 21 of the slag discharge pipe 2 is heated by steam supplied by the steam pipeline 5, so as to prevent the tar in the wastewater from adhering to the pipeline and causing the adverse consequence of pipeline blockage due to the decrease of wastewater temperature when the ammonia distillation tower 1 discharges wastewater.

[0044] Alternatively, if Figure 2 As shown, a heat exchanger 7 is also provided between the sedimentation tank 3 and the backwash tank 4;

[0045] The sedimentation tank 3 and the backwash tank 4 are both connected to the shell side of the heat exchanger 7;

[0046] The remaining ammonia water storage tank 6 is connected to the tube side inlet of the heat exchanger 7 , and the tube side outlet of the heat exchanger 7 is connected to the ammonia distillation tower 1 .

[0047] In the present application, the heat exchanger 7 is provided to utilize the waste water with residual heat discharged from the sedimentation tank 3 to preheat the remaining ammonia water entering the ammonia evaporation tower 1 to be subjected to ammonia evaporation, so as to utilize the heat in the waste water, thereby reducing energy waste.

[0048] When in use, the wastewater containing residual heat discharged from the sedimentation tank 3 enters the shell side of the heat exchanger 7 to heat the residual ammonia water in the tube side to utilize the residual heat in the wastewater. The wastewater after heat exchange is temporarily stored in the backwash tank 4 for subsequent treatment.

[0049] Alternatively, if Figure 3 As shown, the backwash tank 4 is also connected to the cold drum section 8 and the wastewater treatment device 9 respectively.

[0050] In the present application, part of the wastewater in the backwash tank 4 is supplied to the cold drum section 8 for preparing ammonia water, and the other part is sent to the wastewater treatment device 9 for harmless treatment.

[0051] Alternatively, if Figure 4 As shown, the wastewater treatment device 9 includes a nitrogen fixation tank 91, a Fenton oxidation tank 92 and a biochemical treatment tank 93 which are connected in series in sequence;

[0052] The nitrogen fixation tank 91 is also connected to a sodium phosphate solution storage tank 911 and a magnesium chloride solution storage tank 912 respectively.

[0053] In the present application, when in use, part of the wastewater in the backwash tank 4 is sent to the nitrogen fixation tank 91, and the sodium phosphate and magnesium chloride respectively supplied by the sodium phosphate solution storage tank 911 and the magnesium chloride solution storage tank 912 are used to precipitate the ammonia nitrogen in the wastewater in the form of magnesium ammonium phosphate, and the precipitated magnesium ammonium phosphate can be sold as fertilizer. The wastewater after nitrogen fixation treatment in the nitrogen fixation tank 91 is then transported to the Fenton oxidation tank 92, and the organic matter (mainly tar) in the wastewater is oxidized by Fenton oxidation, and the oxidized wastewater is sent to the biochemical treatment tank 93 for biochemical treatment.

[0054] Alternatively, if Figure 5 As shown, the sedimentation tank 3 includes a tank body 31, and a partition wall 32 is vertically arranged in the tank body 31, and the partition wall 32 divides the tank body 31 into a sedimentation area and a drainage area;

[0055] The sedimentation area is connected to the slag discharge pipe 2, and the liquid discharge area is connected to the backwash tank 4;

[0056] The sedimentation area and the drainage area are connected through an overflow trough 33 provided on the upper part of the partition wall 32 .

[0057] In the present application, the sedimentation tank 3 is divided into a sedimentation area and a drainage area by a partition wall 32. The wastewater discharged from the ammonia distillation tower 1 first enters the sedimentation area for sedimentation, and the tar droplets and coke residue in the wastewater are precipitated, and then the wastewater supernatant after precipitation is discharged into the drainage area through the overflow tank. By setting up a sedimentation area to precipitate the tar droplets and coke residue in the wastewater, the tar content in the discharged wastewater can be effectively reduced, thereby reducing the processing workload of the subsequent process.

[0058] Optionally, an interception net 34 is obliquely arranged in the sedimentation area of ​​the sedimentation tank 3;

[0059] The lower side of the interception net 34 is rotatably connected to the bottom of the partition wall 32 , and the upper side of the interception net 34 is connected to the upper part of the partition wall 32 through a restraining rope 35 .

[0060] In the present application, the interception net 34 is provided to intercept the tar droplets and coke residue that cannot be settled by gravity, thereby further reducing the tar content in the discharged wastewater.

[0061] Alternatively, if Figure 6 As shown, a wastewater spray layer 11, a first steam distributor 12 and a liquid storage area 13 are arranged from top to bottom in the ammonia still 1;

[0062] A second steam distributor 14 is also provided in the liquid storage area 13 , and both the first steam distributor 12 and the second steam distributor 14 are connected to the steam pipeline 5 .

[0063] When used in the present application, the remaining ammonia water from the remaining ammonia water storage tank 6 enters the ammonia evaporation tower 1 and is sprayed down from the spray layer 11 at the upper part of the ammonia evaporation tower 1. At the same time, the steam supplied by the steam pipeline 5 is discharged from the first steam distributor 12 and the second steam distributor 14 and countercurrently contacts the remaining ammonia water sprayed down, heating the remaining ammonia water and taking away the ammonia gas in the remaining ammonia water by steam. The falling ammonia water is temporarily stored in the liquid storage area 13 of the ammonia evaporation tower 1 and contacts the steam discharged from the second steam distributor 14 to further take away the ammonia gas in the ammonia water. The ammonia gas evaporated in the ammonia evaporation tower 1 is discharged from the top of the ammonia evaporation tower 1 and enters the corresponding collecting device.

[0064] A coking wastewater ammonia distillation device, the working process of which is as follows:

[0065] When in use, the residual ammonia water from the residual ammonia water storage tank 6 is preheated by the waste water containing heat in the shell side of the heat exchanger 7 when passing through the heat exchanger 7, and the residual heat in the waste water is utilized. The preheated residual ammonia water enters the ammonia evaporation tower 1, and is sprayed down from the spray layer 11 at the upper part of the ammonia evaporation tower 1. At the same time, the steam supplied by the steam pipeline 5 is discharged from the first steam distributor 12 and the second steam distributor 14 to countercurrently contact with the residual ammonia water sprayed down, heating the residual ammonia water and taking away the ammonia gas in the residual ammonia water by steam. The falling ammonia water is temporarily stored in the liquid storage area 13 of the ammonia evaporation tower 1, and contacts with the steam discharged from the second steam distributor 14 to further take away the ammonia gas in the ammonia water. The ammonia gas evaporated in the ammonia evaporation tower 1 is discharged from the top of the ammonia evaporation tower 1 and enters the corresponding collection device.

[0066] When the amount of waste water after ammonia evaporation in the liquid storage area 13 accumulates to a certain value, the waste water needs to be discharged. At this time, the second valve 200 should be opened first, and the inner tube 21 of the slag discharge pipe 2 should be heated by the steam supplied by the steam pipeline 5 to prevent the tar in the waste water from being deposited on the inner wall of the inner tube 21 and causing the slag discharge pipe 2 to be blocked. Then the first valve 100 should be opened to discharge the waste water into the sedimentation tank 3.

[0067] The wastewater entering the sedimentation tank 3 first enters the sedimentation area, and the tar droplets and coke residue in the wastewater will gradually settle at the bottom of the tank. The clarified wastewater on the upper part will then pass through the interception net 34 to intercept the unprecipitated tar droplets, overflow to the drainage area through the overflow tank 33, and then be discharged from the drainage area to enter the shell side of the heat exchanger 7 to heat the remaining ammonia water in the tube side to utilize the remaining heat in the wastewater. The wastewater after heat exchange is temporarily stored in the backwash tank 4. Part of the wastewater in the backwash tank 4 is supplied to the cold drum section 8 for the preparation of ammonia water, and the other part is sent to the nitrogen fixation tank 91. The sodium phosphate and magnesium chloride supplied by the sodium phosphate solution storage tank 911 and the magnesium chloride solution storage tank 912 are used to precipitate the ammonia nitrogen in the wastewater in the form of magnesium ammonium phosphate. The precipitated magnesium ammonium phosphate can be sold as fertilizer. The wastewater after nitrogen fixation treatment in the nitrogen fixation tank 91 is then transported to the Fenton oxidation tank 92, where organic matter (mainly tar) in the wastewater is oxidized by Fenton oxidation. The oxidized wastewater is then transported to the biochemical treatment tank 93 for biochemical treatment.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A coking wastewater ammonia distillation device, characterized in that: It comprises an ammonia still (1), wherein the discharge end at the bottom of the ammonia still (1) is connected to a slag discharge pipe (2); The slag discharge pipe (2) is also connected to the sedimentation tank (3) and the backwash tank (4) in sequence; The slag discharge pipe (2) is connected to the sedimentation tank (3) through a first valve (100), and is connected to the steam pipeline (5) through a second valve (200); The ammonia distillation tower (1) is also connected to a residual ammonia water storage tank (6); The slag discharge pipe (2) comprises an inner pipe (21) and an outer pipe (22), and the steam input end of the outer pipe (22) is connected to a steam pipeline (5).

2. The coking wastewater ammonia distillation device according to claim 1, characterized in that: A heat exchanger (7) is also provided between the sedimentation tank (3) and the backwash tank (4); The sedimentation tank (3) and the backwash tank (4) are both connected to the shell side of the heat exchanger (7); The residual ammonia water storage tank (6) is connected to the tube side inlet of the heat exchanger (7), and the tube side outlet of the heat exchanger (7) is connected to the ammonia distillation tower (1).

3. The coking wastewater ammonia distillation device according to claim 1, characterized in that: The backwash tank (4) is also connected to the cooling drum section (8) and the wastewater treatment device (9) respectively.

4. The coking wastewater ammonia distillation device according to claim 3, characterized in that: The wastewater treatment device (9) comprises a nitrogen fixation tank (91), a Fenton oxidation tank (92) and a biochemical treatment tank (93) which are connected in series in sequence; The nitrogen fixation tank (91) is also connected to a sodium phosphate solution storage tank (911) and a magnesium chloride solution storage tank (912) respectively.

5. The coking wastewater ammonia distillation device according to claim 1, characterized in that: The sedimentation tank (3) comprises a tank body (31), a partition wall (32) is vertically arranged in the tank body (31), and the partition wall (32) divides the tank body (31) into a sedimentation area and a drainage area; The sedimentation zone is connected to the slag discharge pipe (2), and the liquid discharge zone is connected to the backwash tank (4); The sedimentation area and the drainage area are connected through an overflow trough (33) arranged on the upper part of the partition wall (32).

6. The coking wastewater ammonia distillation device according to claim 5, characterized in that: An interception net (34) is obliquely arranged in the sedimentation area of ​​the sedimentation tank (3); The lower side of the intercepting net (34) is rotatably connected to the bottom of the partition wall (32), and the upper side of the intercepting net (34) is connected to the upper part of the partition wall (32) through a restraining rope (35).

7. The coking wastewater ammonia distillation device according to any one of claims 1 to 6, characterized in that: The ammonia still (1) is provided with a wastewater spray layer (11), a first steam distributor (12) and a liquid storage area (13) from top to bottom; A second steam distributor (14) is also provided in the liquid storage area (13), and both the first steam distributor (12) and the second steam distributor (14) are connected to the steam pipeline (5).

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