Device for reducing temperature of flue gas at outlet of packed tower of purification unit

Abstract

The utility model relates to the technical field of chemical engineering, and discloses a device for reducing the temperature of flue gas at an outlet of a packed tower of a purification unit, which comprises a packed tower body, a packed tower circulating pump, a first plate heat exchanger, a second plate heat exchanger, a tail absorption tower body and a tail absorption tower circulating pump, heat exchange is carried out between tail absorption circulating liquid from the tail absorption tower body and purification circulating liquid at an outlet of the second plate heat exchanger, so that the temperature of the purification circulating liquid at the outlet of the second plate heat exchanger is maintained at 32-36 DEG C, and then the purification circulating liquid enters the packed tower body to be sprayed, so that the temperature of flue gas at the outlet of the packed tower body is maintained at 36-38 DEG C; the first-stage electric demister and the downstream drying system are arranged, so that less water entrained in the flue gas enters the first-stage electric demister and the downstream drying system, water balance of the whole acid making system is maintained, heat exchange in the second plate heat exchanger is carried out by virtue of circulating liquid in the tail absorption tower body, and the temperature of the flue gas at the outlet of the packed tower body is indirectly reduced by utilizing the circulating liquid in the tail absorption tower body; and heat exchange circulation in the system is realized, so that the utilization rate of heat is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical engineering, and particularly relates to a device for reducing the temperature of flue gas at the outlet of a packing tower in a purification unit. Background Technique

[0002] The processes of waste acid to acid, pyrite to acid, phosphogypsum to acid, and smelting gas to acid include a purification unit, a drying and absorption unit, a conversion unit, and a tail gas absorption unit. In the purification unit, high-temperature furnace gas enters the drying tower of the downstream system's drying and absorption unit after passing through the stages of quenching and cooling for dust removal, cooling for water removal, and demisting. In the tail gas absorption unit, a small amount of SO2 in the tail gas is removed using a desulfurizing agent and then discharged into the air through a chimney.

[0003] In summer, the air humidity is high, and the cooling effect of the cooling tower is poor, resulting in a relatively high feed water temperature of the circulating water, which causes the temperature of the flue gas at the outlet of the packing tower to exceed 38°C. More moisture will be entrained in the flue gas at the outlet of the packing tower and enter the drying tower of the drying and absorption unit, resulting in an imbalance in the water in the drying and absorption unit and further affecting the concentration of the finished acid. For this reason, a device for reducing the temperature of the flue gas at the outlet of the packing tower in the purification unit is proposed. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a device for reducing the temperature of the flue gas at the outlet of the packing tower in the purification unit, so as to solve the problem proposed in the above background technique that in summer, the air humidity is high, the cooling effect of the cooling tower is poor, resulting in a relatively high feed water temperature of the circulating water, which causes the temperature of the flue gas at the outlet of the packing tower to exceed 38°C. More moisture will be entrained in the flue gas at the outlet of the packing tower and enter the drying tower of the drying and absorption unit, resulting in an imbalance in the water in the drying and absorption unit and further affecting the concentration of the finished acid.

[0005] To achieve the above purpose, the utility model provides the following technical solution: A device for reducing the temperature of the flue gas at the outlet of the packing tower in the purification unit, comprising: a packing tower body, a packing tower circulating pump, a first plate heat exchanger, a second plate heat exchanger, a tail gas absorption tower body, and a tail gas absorption tower circulating pump;

[0006] The first plate heat exchanger and the second plate heat exchanger are connected and installed between the packing tower body and the tail gas absorption tower body, and the packing tower circulating pump and the tail gas absorption tower circulating pump are installed on the sides of the packing tower body and the tail gas absorption tower body;

[0007] The circulating liquid at the bottom of the packing tower body sequentially passes through the packing tower circulating pump, the first plate heat exchanger, and the second plate heat exchanger and then returns to the inlet end of the packing tower body. The circulating liquid at the bottom of the tail gas absorption tower body sequentially passes through the tail gas absorption tower circulating pump and the second plate heat exchanger and then returns to the inlet end of the tail gas absorption tower body.

[0008] Preferably, a flue gas inlet and a flue gas outlet are provided at the upper part of the above-mentioned packing tower body. The flue gas inlet is arranged at the lower side of the packing tower body, and the flue gas outlet is arranged in the middle of the top side of the packing tower body. The flue gas inlet and the flue gas outlet are communicated with each other.

[0009] Preferably, a purified circulating liquid inlet and a purified circulating liquid outlet are provided at the upper part of the above-mentioned packing tower body. The purified circulating liquid inlet and the purified circulating liquid outlet are respectively arranged on the upper and lower sides of the edge of the packing tower body.

[0010] Preferably, the liquid inlet end of the above-mentioned packing tower circulating pump is connected and installed with the purified circulating liquid outlet side of the packing tower body.

[0011] Preferably, the liquid outlet end of the above-mentioned packing tower circulating pump is connected and installed with the heat medium liquid inlet end of the first plate heat exchanger. The refrigerant inlet and outlet ends of the first plate heat exchanger are both connected with circulating water pipes, and circulating water liquid flows inside the circulating water pipes.

[0012] Preferably, the heat medium liquid outlet end of the above-mentioned first plate heat exchanger is connected and installed with the heat medium liquid inlet end of the second plate heat exchanger, and the heat medium liquid outlet end of the second plate heat exchanger is connected and installed with the purified circulating liquid inlet side of the packing tower body.

[0013] Preferably, a tail gas inlet and a tail gas outlet are provided at the upper part of the above-mentioned tail gas absorption tower body. The tail gas inlet is arranged at the lower side of the tail gas absorption tower body, and the tail gas outlet is arranged in the middle of the top side of the tail gas absorption tower body.

[0014] Preferably, a tail gas absorption circulating liquid inlet and a tail gas absorption circulating liquid outlet are provided at the upper part of the above-mentioned tail gas absorption tower body. The tail gas absorption circulating liquid inlet and the tail gas absorption circulating liquid outlet are respectively arranged on the upper and lower sides of the edge of the tail gas absorption tower body.

[0015] Preferably, the liquid inlet end of the above-mentioned tail gas absorption tower circulating pump is connected and installed with the tail gas absorption circulating liquid outlet side of the packing tower body. The liquid outlet end of the tail gas absorption tower circulating pump is connected and installed with the refrigerant liquid inlet end of the second plate heat exchanger, and the refrigerant liquid outlet end of the second plate heat exchanger is connected and installed with the tail gas absorption circulating liquid inlet side of the packing tower body.

[0016] Compared with the prior art, the present utility model adopts the above technical solutions and has the following technical effects:

[0017] 1. The present utility model exchanges heat between the circulating liquid from the tail gas absorption tower body and the purified circulating liquid at the outlet of the second plate heat exchanger, so that the temperature of the purified circulating liquid at the outlet of the second plate heat exchanger is maintained at 32 - 36 °C, and then enters the packing tower body for spraying, thereby maintaining the temperature of the flue gas at the outlet of the packing tower body at 36 - 38 °C, so that less moisture is carried in the flue gas into the primary electric demister and the downstream drying system, further maintaining the water balance of the entire sulfuric acid production system.

[0018] 2. The circulating liquid entering the packing tower body is cooled by double heat exchange relying on the first plate heat exchanger and the second plate heat exchanger, which has a better cooling effect. Moreover, the heat exchange in the second plate heat exchanger relies on the circulating liquid in the tail gas absorption tower body, and the circulating liquid in the tail gas absorption tower body is used to indirectly reduce the temperature of the flue gas at the outlet of the packing tower body, realizing the heat exchange cycle within the system, saving energy and protecting the environment, and greatly improving the utilization rate of heat. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic diagram of the overall installation structure of the device of the present utility model.

[0021] Description of the reference numerals in the drawings: 1. Packing tower body; 2. Packing tower circulating pump; 3. First plate heat exchanger; 4. Second plate heat exchanger; 5. Tail gas absorption tower body; 6. Tail gas absorption tower circulating pump. Detailed Embodiments

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0023] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limited conditions that the present application can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present application can produce and the purposes that can be achieved, should still fall within the scope that the technical content disclosed in the present application can cover.

[0024] Embodiment

[0025] Please refer to Figure 1, the present utility model provides a technical solution: a device for reducing the flue gas temperature at the outlet of the packing tower of the purification unit, including: a packing tower body 1, a packing tower circulation pump 2, a first plate heat exchanger 3, a second plate heat exchanger 4, a tail gas absorption tower body 5, and a tail gas absorption tower circulation pump 6. The packing tower body 1 is used for cooling treatment of sulfur-containing flue gas. The main material of the packing tower body 1 is fiberglass, as shown in the appendix Figure 1 As shown, in order to facilitate the circulation and cooling of sulfur-containing flue gas, a flue gas inlet and a flue gas outlet are provided at the upper part of the packing tower body 1. The flue gas inlet is arranged at the lower side of the packing tower body 1, and the flue gas outlet is arranged in the middle of the top side of the packing tower body 1. The flue gas inlet and the flue gas outlet are connected. In order to facilitate the circulation and recycling of the purification circulating liquid, a purification circulating liquid inlet and a purification circulating liquid outlet are provided at the upper part of the packing tower body 1. The purification circulating liquid inlet and the purification circulating liquid outlet are respectively arranged at the upper and lower sides of the edge of the packing tower body 1.

[0026] The tail gas absorption tower body 5 is used for treating tail gas. The main material of the tail gas absorption tower body 5 is fiberglass. In order to facilitate the introduction and circulation of tail gas, as shown in the appendix Figure 1 As shown, a tail gas inlet and a tail gas outlet are provided at the upper part of the tail gas absorption tower body 5. The tail gas inlet is arranged at the lower side of the tail gas absorption tower body 5, and the tail gas outlet is arranged in the middle of the top side of the tail gas absorption tower body 5. The tail gas inlet is connected to the tail gas outlet. In order to facilitate the circulation and recycling of the tail gas absorption circulating liquid, a tail gas absorption circulating liquid inlet and a tail gas absorption circulating liquid outlet are provided at the upper part of the tail gas absorption tower body 5. The tail gas absorption circulating liquid inlet and the tail gas absorption circulating liquid outlet are respectively arranged at the upper and lower sides of the edge of the tail gas absorption tower body 5.

[0027] The packing tower circulation pump 2 and the tail gas absorption tower circulation pump 6 are used for circulating and pressurizing the conveying of the circulating liquid. Both the packing tower circulation pump 2 and the tail gas absorption tower circulation pump 6 are centrifugal engineering plastic pumps. As shown in the appendix Figure 1 As shown, the packing tower circulation pump 2 and the tail gas absorption tower circulation pump 6 are installed on the side of the packing tower body 1 and the tail gas absorption tower body 5. Specifically, the liquid inlet end of the packing tower circulation pump 2 is connected and installed with the purification circulating liquid outlet side of the packing tower body 1, and the liquid inlet end of the tail gas absorption tower circulation pump 6 is connected and installed with the tail gas absorption circulating liquid outlet side of the packing tower body 1.

[0028] Both the first plate heat exchanger 3 and the second plate heat exchanger 4 are plate seat type hot liquid heat exchangers. The first plate heat exchanger 3 and the second plate heat exchanger 4 are connected and installed between the packing tower body 1 and the tail gas absorption tower body 5. As shown in the appendix Figure 1 As shown, the first plate heat exchanger 3 is used for the primary heat exchange and cooling of the purification circulating liquid. The liquid outlet end of the packing tower circulation pump 2 is connected and installed with the heat medium liquid inlet end of the first plate heat exchanger 3. Both the refrigerant inlet and outlet ends of the first plate heat exchanger 3 are connected with circulating water pipes, and circulating water liquid flows inside the circulating water pipes. The first heat exchange and cooling of the purification circulating liquid can be realized through the heat exchange between the circulating water liquid and the purification circulating liquid in the first plate heat exchanger 3.

[0029] The second plate heat exchanger 4 is used for the secondary heat exchange and cooling of the purified circulating liquid. As shown in Figure 1 the figure, the heat medium liquid outlet end of the first plate heat exchanger 3 is connected and installed with the heat medium liquid inlet end of the second plate heat exchanger 4. The heat medium liquid outlet end of the second plate heat exchanger 4 is connected and installed with the purified circulating liquid inlet side of the packing tower body 1. The liquid outlet end of the tail suction tower circulating pump 6 is connected and installed with the refrigerant liquid inlet end of the second plate heat exchanger 4. The refrigerant liquid outlet end of the second plate heat exchanger 4 is connected and installed with the tail suction circulating liquid inlet side of the packing tower body 1. During the overall working process, the circulating liquid at the bottom of the packing tower body 1 sequentially passes through the packing tower circulating pump 2, the first plate heat exchanger 3, and the second plate heat exchanger 4 and then returns to the inlet end of the packing tower body 1. The circulating liquid at the bottom of the tail suction tower body 5 sequentially passes through the tail suction tower circulating pump 6 and the second plate heat exchanger 4 and then returns to the inlet end of the tail suction tower body 5. Heat exchange is carried out between the circulating liquid from the tail suction tower body 5 and the purified circulating liquid at the outlet of the second plate heat exchanger 4, so that the temperature of the purified circulating liquid at the outlet of the second plate heat exchanger 4 is maintained at 32 - 36 °C, and then it enters the packing tower body 1 for spraying, thereby maintaining the temperature of the flue gas at the outlet of the packing tower body 1 at 36 - 38 °C, so that less moisture is carried in the flue gas into the primary electrostatic precipitator and the downstream drying system, further maintaining the water balance of the entire sulfuric acid production system. The circulating liquid entering the packing tower body 1 relies on the first plate heat exchanger 3 and the second plate heat exchanger 4 for double heat exchange and cooling, having a better cooling effect. And the heat exchange in the second plate heat exchanger 4 relies on the circulating liquid in the tail suction tower body 5, using the circulating liquid in the tail suction tower body 5 to indirectly reduce the temperature of the flue gas at the outlet of the packing tower body 1, realizing the heat exchange cycle within the system, saving energy and being environmentally friendly, and greatly improving the utilization rate of heat.

[0030] Working principle or structural principle. During operation, the flue gas cooling is carried out inside the packing tower body 1. When working, low-temperature sulfur-containing flue gas with a temperature lower than 85 °C is transported into the packing tower body 1 through the flue gas inlet. At the same time, the purified circulating liquid output from the heat medium outlet end of the second plate heat exchanger 4 enters the packing tower body 1 through the purified circulating liquid inlet on the upper side of the packing tower body 1. After the sulfur-containing flue gas and the purified circulating liquid output from the heat medium outlet end of the second plate heat exchanger 4 come into reverse contact, the gas phase temperature of the medium and low-temperature sulfur-containing flue gas in the packing tower body 1 drops to 35 °C. At the same time, the water phase temperature of the purified circulating liquid in the packing tower body 1 rises from room temperature to 60 °C. The heat of the sulfur-containing flue gas is transferred to the purified circulating liquid, completing the cooling treatment of the low-temperature sulfur-containing flue gas. After that, the cooled sulfur-containing flue gas is discharged from the flue gas outlet at the upper part of the packing tower body 1, enters the primary electrostatic precipitator and the secondary electrostatic precipitator of the purification unit to obtain qualified furnace gas, and is sent to the drying tower of the next drying and absorption unit;

[0031] The tail gas treatment is carried out inside the tail gas absorption tower body 5. While cooling the incoming flue gas, low-temperature tail gas at 75°C is input into the tail gas absorption tower body 5 through the tail gas inlet. The tail gas contains no water. At the same time, the tail gas absorption circulating liquid output from the refrigerant liquid storage end of the second plate heat exchanger 4 enters the tail gas absorption tower body 5 through the tail gas absorption circulating liquid inlet on the upper side of the tail gas absorption tower body 5. The low-temperature tail gas contacts the incoming tail gas absorption circulating liquid in a countercurrent manner. The water in the tail gas absorption circulating liquid evaporates rapidly, converting the sensible heat of the medium and low-temperature tail gas into the latent heat of the increased part of the water vapor in the tail gas. At the same time, the temperature of the tail gas also decreases. The temperature of the low-temperature tail gas drops from 75°C to 32°C, and the temperature of the tail gas absorption circulating liquid at the bottom of the tail gas absorption tower body 5 is maintained at 29°C.

[0032] After completing the flue gas cooling work in the packed tower, the purified circulating liquid after temperature rise is output from the purified circulating liquid outlet side at the lower part of the packed tower body 1 under the transportation of the packed tower circulating pump 2. The purified circulating liquid at 60°C enters the inside of the first plate heat exchanger 3 to exchange heat and cool down with the circulating water liquid, completing the first heat exchange and cooling cycle.

[0033] The purified circulating liquid after heat exchange and cooling by the first plate heat exchanger 3 flows out from the heat medium liquid outlet end of the first plate heat exchanger 3, and then the purified circulating liquid enters the second plate heat exchanger 4 through the heat medium liquid inlet end of the second plate heat exchanger 4. At the same time, the tail gas absorption circulating liquid in the tail gas absorption tower body 5 enters the second plate heat exchanger 4 through the refrigerant liquid inlet end of the second plate heat exchanger 4 under the transportation of the tail gas absorption circulating pump 6. In the second plate heat exchanger 4, the purified circulating liquid exchanges heat with the tail gas absorption circulating liquid. The purified circulating liquid is further cooled down, and at the same time, the tail gas absorption circulating liquid exchanges heat and rises in temperature. Then the purified circulating liquid and the tail gas absorption circulating liquid enter the packed tower body 1 and the tail gas absorption tower body 5 respectively, completing the working cycle.

[0034] In summary, the utility model exchanges heat between the circulating liquid from the tail gas absorption tower body 5 and the purified circulating liquid at the outlet of the second plate heat exchanger 4, so that the temperature of the purified circulating liquid at the outlet of the second plate heat exchanger 4 is maintained at 32 - 36°C, and then enters the packed tower body 1 for spraying, thereby maintaining the temperature of the flue gas at the outlet of the packed tower body 1 at 36 - 38°C, so that less moisture is carried in the flue gas into the primary electrostatic precipitator and the downstream drying system, further maintaining the water balance of the entire sulfuric acid production system. The circulating liquid entering the packed tower body 1 relies on the first plate heat exchanger 3 and the second plate heat exchanger 4 for double heat exchange and cooling, having a better cooling effect. And the heat exchange in the second plate heat exchanger 4 relies on the circulating liquid in the tail gas absorption tower body 5, using the circulating liquid in the tail gas absorption tower body 5 to indirectly reduce the temperature of the flue gas at the outlet of the packed tower body 1, realizing the heat exchange cycle within the system, saving energy and protecting the environment, and greatly improving the utilization rate of heat.

[0035] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present utility model can be combined or / and combined in various ways, even if such combinations or combinations are not explicitly recited in the present utility model. In particular, without departing from the spirit and teachings of the present utility model, the features recited in the various embodiments and / or claims of the present utility model can be combined and / and combined in various ways. All such combinations and / and combinations fall within the scope of the present utility model.

Claims

1. A device for reducing the flue gas temperature at the outlet of a purification unit packed tower, characterized in that: include: A packed tower body (1), a packed tower circulating pump (2), a first plate heat exchanger (3), a second plate heat exchanger (4), a tailing absorption tower body (5) and a tailing absorption tower circulating pump (6); The first plate heat exchanger (3) and the second plate heat exchanger (4) are installed in communication between the packing tower body (1) and the tailing tower body (5), and the packing tower circulation pump (2) and the tailing tower circulation pump (6) are installed on the sides of the packing tower body (1) and the tailing tower body (5); The circulating liquid at the bottom of the packed tower body (1) passes through the packed tower circulating pump (2), the first plate heat exchanger (3) and the second plate heat exchanger (4) in sequence, and then returns to the inlet end of the packed tower body (1). The circulating liquid at the bottom of the tailing tower body (5) passes through the tailing tower circulating pump (6) and the second plate heat exchanger (4) in sequence, and then returns to the inlet end of the tailing tower body (5).

2. A device for reducing the flue gas temperature at the outlet of a purification unit packed tower according to claim 1, characterized in that: The upper part of the packed tower body (1) is provided with a smoke inlet and a smoke outlet, the smoke inlet is arranged at the lower side of the packed tower body (1), the smoke outlet is arranged at the middle of the top side of the packed tower body (1), and the smoke inlet and the smoke outlet are connected.

3. A device for reducing the flue gas temperature at the outlet of a purification unit packed tower according to claim 2, characterized in that: The upper part of the packed tower body (1) is provided with a purified circulating liquid inlet and a purified circulating liquid outlet, and the purified circulating liquid inlet and the purified circulating liquid outlet are respectively arranged on the upper and lower sides of the edge of the packed tower body (1).

4. A device for reducing the flue gas temperature at the outlet of a purification unit packed tower according to claim 3, characterized in that: The liquid inlet end of the packed tower circulation pump (2) is connected and installed with the purified circulating liquid outlet side of the packed tower body (1).

5. A device for reducing the flue gas temperature at the outlet of a purification unit packed tower according to claim 4, characterized in that: The liquid outlet end of the packed tower circulation pump (2) is connected to the heat medium liquid inlet end of the first plate heat exchanger (3) and installed, and the refrigerant liquid inlet and outlet ends of the first plate heat exchanger (3) are both connected to a circulating water pipe, and circulating water flows inside the circulating water pipe.

6. A device for reducing the flue gas temperature at the outlet of a purification unit packed tower according to claim 5, characterized in that: The heat medium liquid outlet end of the first plate heat exchanger (3) is connected to the heat medium liquid inlet end of the second plate heat exchanger (4), and the heat medium liquid outlet end of the second plate heat exchanger (4) is connected to the purified circulating liquid inlet side of the packing tower body (1).

7. The device for reducing the flue gas temperature at the outlet of the purification unit packed tower according to claim 1, characterized in that: The upper part of the tail gas absorption tower body (5) is provided with a tail gas inlet and a tail gas outlet, the tail gas inlet is arranged at the lower side of the tail gas absorption tower body (5), and the tail gas outlet is arranged at the middle part of the top side of the tail gas absorption tower body (5).

8. The device for reducing the flue gas temperature at the outlet of the purification unit packed tower according to claim 7, characterized in that: The upper part of the tail suction tower body (5) is provided with a tail suction circulating liquid inlet and a tail suction circulating liquid outlet, and the tail suction circulating liquid inlet and the tail suction circulating liquid outlet are respectively arranged on the upper and lower sides of the edge of the tail suction tower body (5).

9. A device for reducing the flue gas temperature at the outlet of a purification unit packed tower according to claim 8, characterized in that: The liquid inlet end of the tail suction tower circulation pump (6) is connected to the tail suction circulation liquid outlet side of the packed tower body (1), the liquid outlet end of the tail suction tower circulation pump (6) is connected to the refrigerant liquid inlet end of the second plate heat exchanger (4), and the refrigerant liquid outlet end of the second plate heat exchanger (4) is connected to the tail suction circulation liquid inlet side of the packed tower body (1).

Images