A semi-water coal gas spray wastewater deamination system
By using a gas stripping ammonia removal tower and a multi-stage spray absorption system, the problem of high ammonia nitrogen concentration in semi-water gas scrubbing wastewater was solved, achieving efficient removal and recovery of ammonia nitrogen and reducing the treatment load and operating costs of the biochemical system.
Patent Information
- Application Number
- CN202311170859.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-11
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2043-09-11
AI Technical Summary
In ammonia synthesis, the high concentration of ammonia nitrogen in the semi-water gas scrubbing wastewater leads to a high treatment load and consumes a large amount of alkalinity and carbon source when directly introduced into the biochemical system, failing to meet emission requirements.
A combined system consisting of a stripping ammonia removal tower, preheater, reboiler, liquid alkali dosing tank, ammonia condenser, and ammonia absorption tower is adopted. Through countercurrent contact, steam heating, and multi-stage spray absorption, ammonia nitrogen in wastewater is converted and recovered into ammonia gas. The ammonia nitrogen is then separated and recovered using an ammonia condenser and a gas-liquid separator.
It effectively reduced the ammonia nitrogen concentration in wastewater from 3000 mg/L to 150 mg/L, achieving efficient removal and recovery of ammonia nitrogen and reducing the treatment load and operating costs of the biochemical system.
Smart Images
Figure CN117003323B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of ammonia-nitrogen wastewater ammonia removal, and particularly relates to a semi-water coal gas spraying wastewater ammonia removal system. BACKGROUND
[0002] At present, in the synthesis ammonia production, the semi-water coal gas is manufactured by using the fixed bed intermittent method, and the traditional process of circulating water washing and dust removal and temperature reduction is often used for dust removal and temperature reduction of the manufactured semi-water coal gas, in which, the single tower is directly used for water spraying and temperature reduction, that is, the semi-water coal gas is sprayed and cooled by water while entering the gas washing tower, the 35 DEG C cold water from the gas cooling tower cooling water pump is pressurized to 0.3 Mpa, and the cold water is sprayed from the upper empty tower of the gas washing tower through the pipeline, the hot water of about 60 DEG C flows out from the lower part of the gas washing tower, and the outcoming hot water contains part of ash, and the hydrogen sulfide, ammonia-nitrogen, chloride and other substances are dissolved. The ammonia-nitrogen and total nitrogen concentrations of the obtained spraying water are very high, if directly entering the biochemical system, the biochemical system processing load is high, and the discharge requirements cannot be met. Meanwhile, a large amount of alkalinity and carbon source are consumed, and the operation cost is increased, so the ammonia-nitrogen needs to be removed by pretreatment and then enters the biochemical system. SUMMARY
[0003] The present application aims to provide a semi-water coal gas spraying wastewater ammonia removal system, which has the effect of removing ammonia from wastewater.
[0004] The above technical purpose of the present application is realized by the following technical scheme: a semi-water coal gas spraying wastewater ammonia removal system, characterized by comprising a gas stripping ammonia removal tower, a preheater, a reboiler, a liquid alkali dosing tank, an ammonia gas condenser and an ammonia gas absorption tower, the preheater and the liquid alkali dosing tank are connected with the spraying pipe in the gas stripping ammonia removal tower, the reboiler is connected to the bottom of the gas stripping ammonia removal tower, the air outlet of the gas stripping ammonia removal tower is connected with the condenser, and the exhaust port of the condenser is connected with the ammonia gas absorption tower.
[0005] By adopting the above technical scheme, the liquid alkali dosing tank adds sodium hydroxide solution into the wastewater to improve the alkalinity of the ammonia-nitrogen wastewater, the ammonia-nitrogen wastewater is in the upper part of the gas stripping ammonia removal tower and is in countercurrent contact with the steam in the gas stripping ammonia removal tower, the reboiler is used for indirectly heating the wastewater at the bottom of the gas stripping ammonia removal tower to form steam, the steam and the ammonia-containing wastewater are in mass transfer and heat transfer in the tower, the ammonia-nitrogen in the ammonia-containing wastewater is converted into ammonia gas and removed, the high-concentration ammonia-containing gas enriched at the top of the tower enters the ammonia gas condenser, the ammonia water condensed from the ammonia gas condenser is returned to the stripping ammonia removal tower by a reflux pump, and the ammonia gas concentration at the top of the tower is improved. The high-concentration ammonia gas in the ammonia gas condenser and the gas-liquid separation tank is discharged to the ammonia gas absorption tower for recovery.
[0006] The application further provides that a gas-liquid separator is arranged between the ammonia condenser and the ammonia absorption tower, a gas phase outlet of the gas-liquid separator is connected to the ammonia absorption tower, and a liquid phase outlet of the gas-liquid separator is connected to the reboiler.
[0007] By adopting the above technical scheme, the gas discharged from the ammonia condenser contains part of ammonia water, the ammonia water in the gas is separated by the gas-liquid separator, the separated ammonia water enters the reboiler again to form ammonia gas and water vapor by boiling, and the ammonia gas without water enters the ammonia absorption tower.
[0008] The application further provides that the reboiler comprises a shell and two support plates arranged in the shell, the two support plates divide the shell into a liquid return cavity located at two ends of the shell and a heat exchange cavity arranged between the two support plates, a plurality of heat exchange pipes are fixedly connected between the two support plates, two ends of the heat exchange pipes are respectively connected to the two liquid return cavities, a liquid inlet pipe is connected between the lower heat exchange cavity and the bottom of the gas stripping ammonia removal tower, a communication pipe is arranged between the upper heat exchange cavity and the sidewall of the gas stripping ammonia removal tower, a one-way valve is arranged on the liquid inlet pipe, and the one-way valve limits the flow of liquid from the heat exchange cavity to the gas stripping ammonia removal tower.
[0009] By adopting the above technical scheme, the one-way valve arranged on the liquid inlet pipe limits the flow of liquid from the heat exchange cavity to the gas stripping ammonia removal tower, so that the ammonia water entering the reboiler is fully boiled.
[0010] The application further provides that the preheater is a column preheater, and the column preheater is connected to the bottom of the gas stripping ammonia removal tower through a pipeline.
[0011] By adopting the above technical scheme, the liquid level at the bottom of the gas stripping ammonia removal tower is getting higher and higher, and a large amount of heat is contained in the liquid to be discharged, the hot liquid is input into the column heat exchanger through the pipeline to preheat the wastewater entering the gas stripping ammonia removal tower, the utilization rate of heat energy is improved, and the volatilization of ammonia gas is promoted.
[0012] The application further provides that the ammonia absorption tower comprises a tower body, an air inlet and an air outlet are arranged in the tower body and located at the sidewall and the top of the tower body respectively, the air inlet is connected to the gas-liquid separator, a first spray pipe and a second spray pipe are arranged in the tower body and located above the air inlet, the first spray pipe is connected to an external water source through a pipeline, the second spray pipe is connected to the bottom of the tower body through a pipeline, and a partition plate is arranged between the first spray pipe and the second spray pipe.
[0013] By adopting the above technical scheme, the first spray pipe and the second spray pipe are arranged, the first spray pipe enables the external water source to absorb ammonia gas, the second spray pipe enables the ammonia water obtained by spraying of the first spray pipe to absorb ammonia gas again, and the concentration of the ammonia water is improved.
[0014] Further, the partition plate is provided with a guide grid below the second spray pipe on one side, the guide grid comprises a plurality of V-shaped plates fixedly connected in the tower body, the tip of the V-shaped plate is provided with an air inlet on one side, a gap is arranged between two adjacent V-shaped plates, and a liquid discharge chamber is arranged at the lower end of the guide grid.
[0015] By adopting the above technical scheme, the partition plate separates the ammonia water absorbed below the first spray pipe and the second spray pipe, the gas entering the ammonia gas absorption tower passes through the gap between two adjacent V-shaped plates, and after the ammonia water sprayed by the second spray pipe, the ammonia water falls into the groove of the V-shaped plate, and the ammonia water flows to the liquid discharge chamber along the groove of the V-shaped plate.
[0016] Further, a heat exchanger is connected to the pipeline between the second spray pipe and the bottom of the tower body, and the liquid discharge chamber is connected with an ammonia water tank through a pipeline.
[0017] By adopting the above technical scheme, the ammonia gas is dissolved in water to release heat, the heat exchanger cools the ammonia water entering the second spray pipe to improve the solubility of the ammonia gas, and the ammonia water flowing out of the liquid discharge chamber is collected in the ammonia water tank.
[0018] The beneficial effects of the present application are:
[0019] 1. Steam and ammonia-containing wastewater are subjected to mass transfer and heat transfer in the tower, the ammonia nitrogen in the ammonia-containing wastewater is converted into ammonia gas for removal, the high-concentration ammonia gas enriched at the top of the tower enters an ammonia gas condenser, the ammonia water condensed in the ammonia gas condenser is returned to the stripping ammonia removal tower through a reflux pump to improve the concentration of ammonia gas at the top of the tower, and the high-concentration ammonia gas in the ammonia gas condenser and the gas-liquid separation tank is discharged to the ammonia gas absorption tower for recovery, thereby realizing removal and recovery of ammonia nitrogen;
[0020] 2. The spray pipe is provided with the first spray pipe and the second spray pipe, the first spray pipe enables the external water source to absorb ammonia gas, and the second spray pipe enables the ammonia water sprayed by the first spray pipe to absorb ammonia gas again, thereby improving the concentration of the ammonia water;
[0021] 3. The partition plate separates the ammonia water absorbed below the first spray pipe and the second spray pipe, the gas entering the ammonia gas absorption tower passes through the gap between two adjacent V-shaped plates, and after the ammonia water sprayed by the second spray pipe, the ammonia water falls into the groove of the V-shaped plate, and the ammonia water flows to the liquid discharge chamber along the groove of the V-shaped plate. BRIEF DESCRIPTION OF DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those skilled in the art without creative effort based on these drawings also belong to the protection scope of the present application.
[0023] Figure 1 is a structural schematic diagram of the embodiment.
[0024] Figure 2 is a schematic diagram of the connection relationship of the guide grating of the embodiment.
[0025] Figure 3 is a structural schematic diagram of the ammonia absorption tower of the embodiment.
[0026] In the figure, 1 is a stripping ammonia removal tower; 2 is a preheater; 3 is a reboiler; 31 is a shell; 32 is a support plate; 33 is a heat exchange tube; 34 is a liquid inlet pipe; 35 is a communication pipe; 36 is a one-way valve; 4 is a liquid alkali dosing tank; 5 is an ammonia condenser; 6 is an ammonia absorption tower; 61 is a tower body; 62 is an air inlet; 63 is an air outlet; 64 is a spray pipe one; 65 is a spray pipe two; 66 is a partition plate; 67 is a guide grating; 671 is a V-shaped plate; 68 is a liquid discharge chamber; 7 is a gas-liquid separator; and 8 is an ammonia water tank, 81 is a heat exchanger. DETAILED DESCRIPTION
[0027] The technical solutions of the present application will be described clearly and completely in the following with specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort also belong to the protection scope of the present application.
[0028] Embodiment, a semi-water gas spray wastewater ammonia removal system, as shown in Figure 1 , includes a stripping ammonia removal tower 1, a preheater 2, a reboiler 3, a liquid alkali dosing tank 4, an ammonia condenser 5, and an ammonia absorption tower 6. The preheater 2 and the liquid alkali dosing tank 4 are connected with the spray pipe in the stripping ammonia removal tower 1. The reboiler 3 is connected to the bottom of the stripping ammonia removal tower 1. The air outlet of the stripping ammonia removal tower 1 is connected with the condenser. The exhaust port of the condenser is connected with the ammonia absorption tower 6. A gas-liquid separator 7 is arranged between the ammonia condenser 5 and the ammonia absorption tower 6. The gas phase outlet of the gas-liquid separator 7 is connected to the ammonia absorption tower 6. The liquid phase outlet of the gas-liquid separator 7 is connected to the reboiler 3. The preheater 2 is a tube preheater 2, which is connected to the bottom of the stripping ammonia removal tower 1 through a pipeline.
[0029] As shown in Figure 1As shown, the reboiler 3 comprises a shell 31 and two support plates 32 arranged in the shell 31, the two support plates 32 divide the shell 31 into a liquid return cavity at both ends of the shell 31 and a heat exchange cavity arranged between the two support plates 32, a plurality of heat exchange pipes 33 are fixedly connected between the two support plates 32, the two ends of the heat exchange pipes 33 are respectively communicated with the two liquid return cavities, the lower heat exchange cavity is communicated with the bottom of the gas stripping ammonia removal tower 1 through a liquid inlet pipe 34, the upper heat exchange cavity is provided with a communication pipe 35 between the side wall of the gas stripping ammonia removal tower 1, the liquid inlet pipe 34 is provided with a one-way valve 36, the one-way valve 36 limits the flow of liquid from the heat exchange cavity to the gas stripping ammonia removal tower 1.
[0030] As shown in Figure 1 , Figure 2 As shown, the ammonia gas absorption tower 6 comprises a tower body 61, the tower body 61 is provided with a gas inlet 62 located on the side wall of the tower body 61 and a gas outlet 63 located on the top of the tower body 61, the gas inlet 62 is connected with the gas-liquid separator 7, the tower body 61 is provided with a spray pipe one 64 and a spray pipe two 65 located above the gas inlet 62, the spray pipe one 64 is connected with an external water source through a pipeline, the spray pipe two 65 is connected with the bottom of the tower body 61 through a pipeline, and a partition plate 66 is arranged between the spray pipe one 64 and the spray pipe two 65. The partition plate 66 is obliquely provided with a guide grid 67 located below the spray pipe two 65 on one side, the guide grid 67 comprises a plurality of V-shaped plates 671 fixedly connected in the tower body 61, the tip of the V-shaped plate 671 is arranged towards the side of the air inlet, a gap is arranged between the adjacent two V-shaped plates 671, and the lower end of the guide grid 67 is provided with a liquid discharge chamber 68. The pipeline between the spray pipe two 65 and the bottom of the tower body 61 is connected with a heat exchanger 81, and the liquid discharge chamber 68 is connected with an ammonia water tank 8 through a pipeline.
[0031] When the semi-water coal gas spray wastewater ammonia removal system is used, the liquid caustic dosing tank 4 adds sodium hydroxide solution to the wastewater to increase the alkalinity of the ammonia-nitrogen wastewater, the ammonia wastewater in the upper part of the stripping ammonia removal tower 1 flows downward and countercurrently contacts the steam in the stripping ammonia removal tower 1, the reboiler 3 is used to indirectly heat the wastewater at the bottom of the stripping ammonia removal tower 1 to form steam, the steam and the ammonia-containing wastewater in the tower perform mass transfer and heat transfer, the ammonia-nitrogen in the ammonia-containing wastewater is converted into ammonia gas and removed, the high-concentration ammonia-containing gas enriched at the top of the tower enters the ammonia gas condenser 5, the ammonia water condensed by the ammonia gas condenser 5 is returned to the stripping ammonia removal tower by the reflux pump to improve the ammonia gas concentration at the top of the tower. The high-concentration ammonia gas in the ammonia gas condenser 5 and the gas-liquid separation tank is discharged to the ammonia gas absorption tower 6 for recovery, the spray pipe one 64 and the spray pipe two 65 are arranged, the spray pipe one 64 makes the external water source absorb the ammonia gas, the spray pipe two 65 makes the ammonia water obtained by spraying the spray pipe one 64 absorb the ammonia gas again, thereby improving the concentration of the ammonia water, the separation plate 66 separates the ammonia water absorbed below the spray pipe one 64 and the spray pipe two 65, the gas entering the ammonia gas absorption tower 6 passes through the gap between the adjacent two V-shaped plates 671, after the liquid ammonia water sprayed by the spray pipe two 65, the ammonia water falls into the groove of the V-shaped plate 671, the ammonia water flows along the groove of the V-shaped plate 671 to the liquid discharge chamber 68, the ammonia water flowing out of the liquid discharge chamber 68 enters the ammonia water tank 8 for collection, after detection, the total nitrogen concentration of the nitrogen ammonia wastewater entering the preheater 2 is as high as 3000 mg / L, finally, the ammonia-nitrogen of the effluent discharged from the bottom of the stripping ammonia removal tower 1 is ≤150 mg / L, and the concentration of the ammonia water recovered in the ammonia water tank 8 is 10%-15%.
Claims
1. A semi-water gas spray wastewater deaminating system, characterized in that: The application relates to a stripping ammonia removal tower (1), a preheater (2), a reboiler (3), a liquid alkali dosing tank (4), an ammonia gas condenser (5) and an ammonia gas absorption tower (6), the preheater (2) and the liquid alkali dosing tank (4) are connected with spray pipes in the stripping ammonia removal tower (1), the reboiler (3) is connected to the bottom of the stripping ammonia removal tower (1), the air outlet of the stripping ammonia removal tower (1) is connected with the condenser, and the exhaust port of the condenser is connected with the ammonia gas absorption tower (6); A gas-liquid separator (7) is arranged between the ammonia gas condenser (5) and the ammonia gas absorption tower (6), the gas phase outlet of the gas-liquid separator (7) is connected with the ammonia gas absorption tower (6), and the liquid phase outlet of the gas-liquid separator (7) is connected with the reboiler (3); The reboiler (3) comprises a shell (31) and two support plates (32) arranged in the shell (31), the two support plates (32) divide the shell (31) into a liquid return cavity located at the two ends of the shell (31) and a heat exchange cavity arranged between the two support plates (32), a plurality of heat exchange pipes (33) are fixedly connected between the two support plates (32), the two ends of the heat exchange pipes (33) are respectively connected with the two liquid return cavities, a liquid inlet pipe (34) is arranged between the lower heat exchange cavity and the bottom of the stripping ammonia removal tower (1), a communication pipe (35) is arranged between the upper heat exchange cavity and the side wall of the stripping ammonia removal tower (1), a one-way valve (36) is arranged on the liquid inlet pipe (34), and the one-way valve (36) limits the flow of liquid from the heat exchange cavity to the stripping ammonia removal tower (1); The preheater (2) is a column preheater (2), and the column preheater (2) is connected with the bottom of the stripping ammonia removal tower (1) through a pipeline; The ammonia gas absorption tower (6) comprises a tower body (61), the tower body (61) is provided with an air inlet (62) and an air outlet (63), the air inlet (62) is connected with the gas-liquid separator (7), the tower body (61) is provided with a first spray pipe (64) and a second spray pipe (65) located above the air inlet (62), the first spray pipe (64) is connected with an external water source through a pipeline, the second spray pipe (65) is connected with the bottom of the tower body (61) through a pipeline, and a partition plate (66) is arranged between the first spray pipe (64) and the second spray pipe (65).
2. The semi-water gas spray wastewater deaminating system according to claim 1, characterized in that: One side of the partition plate (66) is obliquely provided with a guide grid (67) located below the second spray pipe (65), the guide grid (67) comprises a plurality of V-shaped plates (671) fixedly connected in the tower body (61), the tip of the V-shaped plate (671) faces the air inlet side, gaps are arranged between adjacent two V-shaped plates (671), and the lower end of the guide grid (67) is provided with a liquid discharge chamber (68).
3. The semi-water gas spray wastewater deaminating system according to claim 2, characterized in that: A heat exchanger (81) is connected to the pipeline between the second spray pipe (65) and the bottom of the tower body (61), and the liquid discharge chamber (68) is connected with an ammonia water tank (8) through a pipeline.
Citation Information
Patent Citations
Negative-pressure ammonia nitrogen wastewater treatment and ammonia recovery device and technology
CN108726617A