Temporary treatment device for tower top ammonia gas of ammonia still

Abstract

The utility model belongs to the technical field of recovery and ammonia distillation of coke oven products, and particularly relates to a temporary treatment device for tower top ammonia gas of an ammonia distillation tower, which is characterized by comprising an overflow pipe, an ammonia condensate tank and a heat tracing device, one end of the overflow pipe is connected with a top outlet of the ammonia distillation tower, the other end of the overflow pipe is connected with a chimney, and the overflow pipe is an inverted n-shaped pipe body; the ammonia condensate tank is arranged at the lowest point of the overflow pipe; the access point of the overflow pipe and the chimney is not higher than 40% of the total height of the chimney; a heat tracing device is arranged on the inner side and / or the outer side of the overflow pipe. Compared with the prior art, the device has the beneficial effects that as a temporary measure, when a follow-up unit cannot be normally put into use at the initial working stage, the ammonia gas is connected into the chimney through the temporary pipeline, cooling equipment and treatment equipment are not additionally arranged, the temporary emission of the ammonia gas at the top of the ammonia still is realized, and the ammonia gas is emitted after being diluted by gas in the chimney; the environmental pollution is reduced; and an original pipeline can be transformed, and the practicability is high.

Description

Technical Field

[0001] The utility model belongs to the technical field of ammonia distillation in the recovery of coking products, and particularly relates to a temporary treatment device for ammonia gas at the top of an ammonia distillation tower. Background Art

[0002] As one of the main processes for coking gas purification at present, the remaining ammonia water is distilled in an ammonia distillation tower with steam to distill out ammonia, and the remaining ammonia distillation wastewater reaches the bottom of the tower. Alkali liquor is also added in the ammonia distillation tower to decompose the fixed ammonia. The decomposed ammonia is also treated by steam stripping. The ammonia-free distillation wastewater is pumped out from the bottom of the ammonia distillation tower by an ammonia distillation wastewater pump, cooled by an ammonia distillation wastewater cooler, and then sent to a temporary biochemical treatment device for wastewater. The ammonia-containing steam leaving the ammonia distillation tower enters the next process section and enters different devices according to different processes: in the AS process, it enters a deacidification tower to utilize its heat for rich liquid deacidification; in the HPF process, it enters a desulfurization tower as a supplementary alkali source for desulfurization. The temperature in the chimney is 180°C to 280°C, the pressure is about -230 Pa, and ammonia gas exists in a gaseous state therein, and the concentration will drop to a very low level, and the emission height reaches 160 m.

[0003] The Chinese utility model patent with the application number 202321376761.8 discloses a recovery system for fixed ammonia in ammonia distillation tower condensate, which includes a positive-pressure ammonia distillation system, a negative-pressure ammonia distillation system, a light liquid barrel, a flash evaporator, and a light liquid tower. The positive-pressure ammonia distillation system includes a positive-pressure ammonia distillation tower, a first ammonia gas condenser, a first ammonia gas cooler, a first separator, and a first absorption tower; the negative-pressure ammonia distillation system includes a negative-pressure ammonia distillation tower, a second ammonia gas condenser, a second ammonia gas cooler, a second separator, and a second absorption tower. The hot medium liquid phase outlet of the second ammonia gas condenser connected to the negative-pressure ammonia distillation tower is communicated with the liquid inlet at the upper part of the positive-pressure ammonia distillation tower. This scheme uses the condensate formed after condensing the ammonia gas entrained with mother liquor in the negative-pressure ammonia distillation tower to be transported to the positive-pressure ammonia distillation tower to distill out the fixed ammonia therein, recycle the ammonia, and reduce ammonia loss in the process. However, it does not mention the situation where the ammonia distillation tower operates during the initial stage of construction and the ammonia gas does not operate in the subsequent stage, or the situation of maintenance in the subsequent stage of ammonia gas as a temporary emission measure for short-term emission and treatment, and has no reference value. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a temporary treatment device for ammonia gas at the top of an ammonia distillation tower, to overcome the deficiencies of the prior art. When the subsequent unit cannot be put into normal use during the initial construction period, the ammonia gas is connected to the chimney, and a part of the condensed ammonia water in the pipeline is harmlessly treated, so as to realize the temporary emission of ammonia gas at the top of the ammonia distillation tower, and after being diluted by the gas in the chimney, it is discharged, reducing environmental pollution.

[0005] To achieve the above purpose, the utility model is realized through the following technical solutions:

[0006] An ammonia vapor temporary treatment device for the top of an ammonia distillation column, comprising an overflow pipe, an ammonia condensate tank, and a heat tracing device. One end of the overflow pipe is connected to the top outlet of the ammonia distillation column, and the other end of the overflow pipe is connected to a chimney. The overflow pipe is in the shape of an inverted "J" tube body, and the ammonia condensate tank is arranged at the lowest point of the overflow pipe; the connection point of the overflow pipe and the chimney is not higher than 40% of the total height of the chimney; a heat tracing device is provided on the inner side and / or the outer side of the overflow pipe.

[0007] Further, the heat tracing device is an electric heat tracing band or a steam jacket.

[0008] Further, a dilute hydrochloric acid supply pipeline is connected to the ammonia condensate tank.

[0009] Further, the other end of the overflow pipe is connected to a spray pipe inside the chimney, and a stainless steel spiral nozzle is provided on the spray pipe.

[0010] Further, the distance between the highest point and the lowest point of the overflow pipe is 20 - 40 meters.

[0011] Further, the overflow pipe is made of S31603 stainless steel pipe or a carbon steel pipe lined with S31603 anti-corrosion coating.

[0012] Further, there are multiple trays assemblies inside the ammonia distillation column. One tray assembly includes a distribution tray on the upper part and an overflow tray on the lower part. A circle of overflow baffles is provided around the periphery of the distribution tray body. The distribution tray is arranged on the internal support of the ammonia distillation column and is suspended around the periphery; the overflow tray has a central hole, and a circle of enclosing plates is provided at the edge of the hole. The periphery of the overflow tray is closely connected to the inner wall of the ammonia distillation column.

[0013] Further, the bottom of the overflow pipe has a gas-liquid separation space, and the cross-section of the bottom is 2 - 6 times that of the cross-section of the downcomer.

[0014] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0015] 1) As a temporary measure, when the subsequent unit cannot be put into normal use at the initial stage of operation, the ammonia gas is connected to the chimney through a temporary pipeline without adding new cooling equipment and treatment equipment, realizing the temporary discharge of the ammonia gas at the top of the ammonia distillation column. The ammonia gas is discharged after being diluted by the gas in the chimney, reducing environmental pollution;

[0016] 2) An ammonia condensate tank is provided, which can prevent the condensate from blocking the pipeline and harmlessly treat a part of the ammonia water condensed in the pipeline, appropriately reducing the ammonia gas emission;

[0017] 3) This process can be modified on the original pipeline, and the feasibility is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of an embodiment of the present utility model;

[0019] Figure 2 It is a schematic diagram of the tray structure in the embodiment of the present utility model;

[0020] Figure 3 It is a schematic diagram of the structure of the first example of the heat tracing device in the embodiment of the present utility model;

[0021] Figure 4 It is a schematic diagram of the structure of the second example of the heat tracing device in the embodiment of the present utility model.

[0022] In the figure: 1 - ammonia stripping tower, 2 - chimney, 3 - ammonia condensate tank, 4 - liquid inlet, 5 - overflow pipe, 6 - steam port, 7 - waste water pipe, 8 - dilute hydrochloric acid supply pipeline, 9 - spray pipe, 10 - heat tracing device, 11 - distribution tray, 12 - overflow tray, 13 - overflow baffle, 14 - enclosure board. Specific embodiments

[0023] Next, the technical solutions of the present utility model will be clearly and completely described in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of the embodiments.

[0024] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the specific embodiments required for use in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other specific embodiments can be obtained based on these specific embodiments.

[0025] Generally, the components of the embodiments of the present utility model described and shown in the specific embodiments here can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present utility model provided in the specific embodiments is not intended to limit the scope of the present utility model to be protected, but only represents the selected embodiments of the present utility model.

[0026] See Figure 1, which is a schematic structural diagram of an embodiment of a temporary ammonia treatment device at the top of an ammonia distillation tower of the present utility model, includes an overflow pipe 5, an ammonia condensate tank 3, and a heat tracing device 10. One end of the overflow pipe 5 is connected to the top outlet of the ammonia distillation tower 1, and the other end of the overflow pipe 5 is connected to a chimney 2. The overflow pipe 5 is an inverted U-shaped pipe body, and the ammonia condensate tank 3 is arranged at the lowest point of the overflow pipe 5; the connection point of the overflow pipe 5 and the chimney 2 is not higher than 40% of the total height of the chimney 2. For a 160-meter-high chimney, the connection point is preferably at 62.5 meters; a heat tracing device 10 is provided on the inner side and / or the outer side of the overflow pipe 5. A dilute hydrochloric acid supply pipeline 8 is connected to the ammonia condensate tank 3. The other end of the overflow pipe 5 is connected to a spray pipe 9 inside the chimney 2. The spray pipe 9 is provided with a stainless steel spiral nozzle, which can make the ammonia gas and the flue gas mix more fully.

[0027] The distance between the highest point and the lowest point of the overflow pipe 5 is 20 - 40 meters. The overflow pipe 5 is made of S31603 stainless steel pipe or a carbon steel pipe lined with S31603 anti-corrosion coating, which has a long service life.

[0028] See Figure 2 , a multi-layer tray assembly is provided inside the ammonia distillation tower 1. One layer of the tray assembly includes a distribution tray 11 on the upper part and an overflow tray 12 on the lower part. A circle of overflow baffles 13 is provided on the periphery of the tray body of the distribution tray 11. The distribution tray 11 is arranged on the internal support of the ammonia distillation tower 1 and is suspended on the periphery; the overflow tray 12 has a central opening, and a circle of enclosing plates 14 is provided on the edge of the hole. The periphery of the overflow tray 12 is closely connected to the inner wall of the ammonia distillation tower 1. This tray structure can maximize the contact between steam and residual ammonia water, and make the separation of ammonia gas and water more thorough.

[0029] See Figure 3 , the heat tracing device 10 is an electric heat tracing belt. The bottom of the overflow pipe 5 has a gas-liquid separation space, and the cross-section D at the bottom is 2 - 6 times that of the cross-section d of the downcomer. The enlarged space at the bottom of the overflow pipe 5 can prevent the condensate from blocking the pipeline and affecting the discharge of ammonia gas.

[0030] See Figure 4 , the heat tracing device 10 is a steam jacket, and the steam jacket is arranged on the outer side of the pipe body, and steam is introduced into the middle to keep the inside of the overflow pipe at a suitable temperature.

[0031] The temporary treatment method for ammonia gas at the top of the ammonia distillation tower of the present utility model is as follows: After the surplus ammonia water enters the ammonia distillation tower 1 from the liquid inlet 4 above the tray, it contacts countercurrently with the steam entering from the steam port 6 at the bottom of the ammonia distillation tower 1. The ammonia gas is heated and separated from the wastewater. As a temporary measure, the ammonia gas is discharged from the exhaust port at the top of the ammonia distillation tower 1 into the overflow pipe 5, and the wastewater is discharged from the wastewater pipe 7 at the bottom of the ammonia distillation tower 1 to the water treatment unit; the ammonia gas first descends and then ascends along the inverted U-shaped pipe body in the overflow pipe 5, and finally enters the chimney 2 and is diluted by the flue gas and then discharged. During the flowing process, the ammonia gas is further separated from the water vapor. The water vapor condenses and flows into the ammonia condensate tank 3, and the ammonia condensate is neutralized with dilute hydrochloric acid and discharged harmlessly; the temperature throughout the overflow pipe 5 is not lower than 95 °C. A heat preservation device is provided outside the overflow pipe 5 to reduce energy consumption.

[0032] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A temporary treatment device for ammonia gas at the top of an ammonia distillation tower, characterized in that It includes an overflow pipe, an ammonia condensate tank and a tracing device. One end of the overflow pipe is connected to the top outlet of the ammonia distillation tower, and the other end of the overflow pipe is connected to a chimney. The overflow pipe is in an inverted "J" - shaped pipe body, and the ammonia condensate tank is arranged at the lowest point of the overflow pipe; the connection point of the overflow pipe and the chimney is not higher than 40% of the total height of the chimney; a tracing device is provided on the inner side and / or the outer side of the overflow pipe.

2. The temporary ammonia treatment device at the top of the ammonia stripping tower according to claim 1, characterized in that, The tracing device is an electric heating tape or a steam jacket.

3. The temporary ammonia treatment device at the top of the ammonia stripping tower according to claim 1, characterized in that, A dilute hydrochloric acid supply pipeline is connected to the ammonia condensate tank.

4. An ammonia temporary treatment device at the top of an ammonia distillation column according to claim 1, characterized in that, The other end of the overflow pipe is connected to a spray pipe inside the chimney, and a stainless - steel spiral nozzle is provided on the spray pipe.

5. The temporary treatment device for ammonia gas at the top of an ammonia distillation column according to claim 1, wherein The distance between the highest point and the lowest point of the overflow pipe is 20 - 40 meters.

6. The temporary ammonia treatment device at the top of the ammonia stripping tower according to claim 1, characterized in that The overflow pipe is made of S31603 stainless - steel pipe or a carbon steel pipe lined with S31603 anti - corrosion coating.

7. An ammonia vapor temporary treatment device at the top of an ammonia distillation column according to claim 1, characterized in that, Multiple trays assemblies are provided inside the ammonia distillation tower. One tray assembly includes a distribution tray on the upper part and an overflow tray on the lower part. A circle of overflow baffles is provided around the periphery of the distribution tray body. The distribution tray is arranged on the internal support of the ammonia distillation tower and is suspended around the periphery; the overflow tray has a central opening, and a circle of baffles is provided at the edge of the hole. The periphery of the overflow tray is closely connected to the inner wall of the ammonia distillation tower.

8. An ammonia temporary treatment device at the top of an ammonia distillation column according to claim 1, characterized in that, The bottom of the overflow pipe has a gas - liquid separation space, and the cross - section of the bottom is 2 - 6 times that of the down - pipe cross - section.

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