Evaporation tower for desulfurization wastewater

Abstract

This invention relates to the field of desulfurization wastewater treatment and discloses a drying tower for desulfurization wastewater, comprising a vertically extending body section (1) capable of accommodating flue gas, a spray gun (2) disposed in the body section (1) for spraying desulfurization wastewater, and a rectifier (3) disposed in the body section (1) and located below the spray gun (2). The outlet of the spray gun (2) is oriented vertically upward. Multiple rectifier channels extending vertically and arranged horizontally are formed in the rectifier (3) so that the airflow after passing through the rectifier (3) flows vertically upward. Through the above technical solution, the rectifier can adjust the flue gas upstream of the spray gun to flow in a direction that is basically along the extension direction of the flue, reducing turbulence and making the flue gas and the desulfurization wastewater sprayed from the spray gun flow in the same direction, avoiding the desulfurization wastewater from colliding with the inner wall of the flue, thereby avoiding the problems of fouling, corrosion, and scaling of the desulfurization wastewater on the inner wall of the flue.

Description

Technical Field

[0001] This invention relates to the field of desulfurization wastewater treatment, and more specifically to a drying tower for desulfurization wastewater. Background Technology

[0002] In recent years, air pollution has become an increasingly prominent problem. Wet desulfurization, especially limestone-gypsum desulfurization technology, has been widely adopted as the main desulfurization process. However, the desulfurization wastewater generated after wet desulfurization has strong corrosive and scaling properties due to its high chlorine content, high salt content, and high hardness, making it difficult for power plants to reuse and becoming the most difficult wastewater for power plants to treat.

[0003] Currently, commonly used zero-discharge treatment processes for desulfurization wastewater include MVR (mechanical vapor recompression) evaporation crystallization, MED (multiple effect distillation) evaporation crystallization, and flue gas evaporation technology. Among these, MVR and MED technologies have disadvantages such as high investment costs, large footprint, and high operating costs, which limit their widespread use.

[0004] Flue gas evaporation technology typically involves installing atomizing spray guns directly in existing flues to spray desulfurization wastewater, mix it with flue gas, and then evaporate it. The evaporated crystalline particles, along with the flue gas dust, enter the dust collector for removal. This technology has advantages such as lower investment and operating costs.

[0005] However, current flue gas evaporation technologies suffer from several drawbacks. Due to the presence of bends, diameter changes, and irregular structural sections in the flue gas duct, the flue gas lacks proper guidance or rectification before reaching the atomizing nozzle, leading to flow deviation or turbulence. This results in a mismatch between the flue gas flow rate and the volume of desulfurization wastewater sprayed by the atomizing nozzle, or a misalignment between the flue gas flow direction and the nozzle's spray direction. Consequently, the atomized desulfurization wastewater is sprayed onto the flue gas wall before complete evaporation, causing problems such as fouling, corrosion, and scaling. Even worse, insufficient flue length and uneven flow velocity can cause flue gas deviation, resulting in some high-velocity flue gas carrying incompletely evaporated atomized desulfurization wastewater directly into the dust collector, severely impacting the dust collection equipment. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of fouling, corrosion, and scaling on the inner wall of flue during desulfurization wastewater treatment.

[0007] To achieve the above objectives, the present invention provides a drying tower for desulfurization wastewater, wherein the drying tower includes a vertically extending body portion capable of accommodating flue gas, a spray gun disposed in the body portion for spraying desulfurization wastewater, and a rectifier disposed in the body portion and located below the spray gun. The outlet of the spray gun is oriented vertically upward, and a plurality of rectifier channels are formed in the rectifier, extending vertically and arranged horizontally, so that the airflow after passing through the rectifier flows in a vertically upward direction.

[0008] In some embodiments, the rectifier includes plates that intersect horizontally and vertically parallel to the vertical direction.

[0009] In some embodiments, the drying tower includes a curved flue and an intermediate flue located upstream of the main body, the curved flue having an inlet facing a first side in a first horizontal direction and an outlet facing upward in a vertical direction, the intermediate flue being connected to the outlet of the curved flue.

[0010] In some embodiments, a first guide element is provided in the intermediate flue, which guides the airflow to deflect towards the first side along the first horizontal direction.

[0011] In some embodiments, the first guide member includes a plurality of first guide plates stacked and spaced apart along the first horizontal direction, the upper end of the first guide plate being deflected toward the first side relative to its lower end to form a plurality of first guide channels deflected toward the first side.

[0012] In some embodiments, the drying tower includes a gradually expanding flue connecting the intermediate flue and the main body, wherein the inlet cross-sectional dimension of the main body is larger than the outlet cross-sectional dimension of the intermediate flue, and the cross-section of the gradually expanding flue gradually increases in the vertical direction.

[0013] In some embodiments, the cross-sections of the main body, the turning flue, the intermediate flue, and the gradually widening flue are rectangular.

[0014] In some embodiments, the main body, the turning flue, the intermediate flue, and the expanding flue have the same dimensions in a second horizontal direction perpendicular to the first horizontal direction, and the dimension of the expanding flue in the first horizontal direction gradually increases in the vertically upward direction.

[0015] In some embodiments, a second flow guide is disposed in the gradually expanding flue. The second flow guide includes a plurality of second flow guide plates stacked and spaced apart along the first horizontal direction. The second flow guide plates located on the first side of the centerline of the gradually expanding flue along the first horizontal direction are respectively deflected to the first side, and the second flow guide plates located on the second side of the centerline of the gradually expanding flue along the first horizontal direction are respectively deflected to the second side, thereby forming a second flow guide channel deflected from the center to both sides.

[0016] In some embodiments, the drying tower includes a plurality of spray guns spaced apart along the first horizontal direction and inserted into the body along the second horizontal direction, the outlets of the spray guns maintaining a predetermined distance from the inner wall of the body.

[0017] In some embodiments, the rectifier forms a plurality of rectifier channels with the same cross-section in the body portion.

[0018] In some embodiments, a burner is connected to the inlet of the turning flue.

[0019] In some embodiments, the outlet of the main body is connected to an outlet flue.

[0020] Through the above technical solution, the rectifier can adjust the flue gas upstream of the spray gun to flow in a direction that is basically along the extension of the flue, reducing turbulence and making the flue gas and the desulfurization wastewater sprayed from the spray gun flow in the same direction, avoiding the desulfurization wastewater from colliding with the inner wall of the flue, thereby avoiding the problems of fouling, corrosion and scaling of the desulfurization wastewater on the inner wall of the flue. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the evaporation tower according to an embodiment of the present invention;

[0022] Figure 2 This is a cross-sectional view of the drying tower according to an embodiment of the present invention, which shows the arrangement of the spray guns;

[0023] Figure 3 This is a cross-sectional view of the evaporation tower according to an embodiment of the present invention, which shows the arrangement of the rectifiers;

[0024] Figure 4 This is a front view of the evaporation tower according to an embodiment of the present invention, which shows the dimensions of each part;

[0025] Figure 5 This is a side view of the evaporation tower according to an embodiment of the present invention, showing the dimensions of each part;

[0026] Figure 6This is a velocity cloud diagram of the central axis surface of the evaporation tower without guides and rectifiers according to an embodiment of the present invention.

[0027] Figure 7 This is a velocity cloud diagram of the central axis surface of the evaporation tower in an embodiment of the present invention, with and without flow guides and rectifiers.

[0028] Figure 8 This is a front view of the residence time of atomized droplets of desulfurized wastewater when the evaporation tower has no guide or rectifier components according to an embodiment of the present invention.

[0029] Figure 9 This is a 3D diagram showing the residence time of atomized droplets of desulfurized wastewater when the evaporation tower has no guide or rectifier components according to an embodiment of the present invention.

[0030] Figure 10 This is a front view of the residence time of atomized droplets of desulfurized wastewater when the evaporation tower of the present invention has flow guides and rectifiers;

[0031] Figure 11 This is a 3D diagram showing the residence time of atomized droplets of desulfurized wastewater when the evaporation tower of this invention has flow guides and rectifiers.

[0032] Explanation of reference numerals in the attached figures

[0033] 1-Main body, 2-Spray gun, 3-Rectifier, 4-Turn flue, 5-Intermediate flue, 6-First guide, 7-Second guide, 8-Expanding flue, 9-Outlet flue. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0035] refer to Figures 1-5 As shown, the present invention provides a drying tower for desulfurization wastewater, wherein the drying tower includes a vertically extending body 1 capable of accommodating flue gas, a spray gun 2 disposed in the body 1 for spraying desulfurization wastewater, and a rectifier 3 disposed in the body 1 and located below the spray gun 2. The outlet of the spray gun 2 is oriented vertically upward, and the rectifier 3 forms a plurality of rectifier channels extending vertically and arranged horizontally, so that the airflow after passing through the rectifier 3 flows in a vertically upward direction.

[0036] The evaporation tower can be connected to the flue gas after combustion, for example, it can be introduced into the main body 1. The flue gas is used to evaporate the desulfurization wastewater sprayed from the spray gun 2, so that the water evaporates into gas. The crystallized particles and dust can be separated by a dust collector to achieve the treatment of sulfur-containing wastewater.

[0037] The main body 1 is vertically arranged, forming a vertically upward cavity that allows flue gas to pass through. The spray gun 2 is oriented vertically upward, so that liquid, such as desulfurization wastewater, can be sprayed in a vertically upward direction. The desulfurization wastewater mixes with the flue gas and absorbs heat to be evaporated and form crystalline particles.

[0038] Specifically, the main body 1 is provided with a rectifier 3, which is located on the lower side of the spray gun 2, that is, upstream of the spray gun 2 in the direction of flue gas flow, and can rectify the flue gas before it reaches the spray gun 2.

[0039] The rectifier 3 forms rectifier channels that extend vertically. These rectifier channels are arranged horizontally. In other words, the rectifier 3 forms more vertically extending channels with smaller flow areas in the body part 1, so that the airflow passing through them also flows vertically upward.

[0040] It can be seen that by setting the rectifier 3 in the main body 1 with a large overall flow area, multiple rectifier channels with smaller flow areas can be formed, so that the flue gas is rectified in a smaller range, forming a flue gas airflow that is vertically upward, avoiding or reducing the generation of turbulence. Downstream of the rectifier 3, an overall airflow that is basically vertically upward is formed, so that the flue gas carrying the desulfurization wastewater flows vertically upward, avoiding or reducing the movement of the flue gas carrying the desulfurization wastewater laterally in the main body 1, avoiding or reducing the collision of the desulfurization wastewater with the inner wall of the main body, which would lead to fouling, corrosion and scaling, so as to better protect the flue of the main body.

[0041] like Figure 3 As shown, the rectifier 3 includes horizontally and vertically intersecting plates parallel to the vertical direction. The rectifier 3 forms a grid structure through the horizontally and vertically intersecting plates. These plates have a certain size in the vertical direction, thereby forming a rectifier channel with a certain length in the vertical direction. This ensures that the flue gas flow travels a sufficient distance in the rectifier channel, achieving the rectification effect on the flue gas flow and adjusting the flue gas flow to flow in the vertical direction.

[0042] Additionally, the drying tower includes a turning flue 4 and an intermediate flue 5 located upstream of the main body 1. The turning flue 4 has an inlet facing a first side in a first horizontal direction and an outlet facing upward in a vertical direction. The intermediate flue 5 is connected to the outlet of the turning flue 4. The inlet of the turning flue 4 can be connected to other flues to receive flue gas flowing in a horizontal direction and turn the horizontally flowing flue gas into a generally vertically flowing direction. The structure of the turning flue 4 allows the main body 1 to be used as a device to generate horizontally flowing flue gas. The intermediate flue 5, as a transition flue, allows the flue gas flow from the turning flue 4 to transition into the main body 1, and can, to a certain extent, regulate the flue gas flow with a relatively complex flow direction after the turn to flow in a vertically upward direction. The inlet and outlet dimensions of the turning flue 4 are basically the same, especially their cross-sectional shapes can be kept consistent; the overall cross-sectional shape of the intermediate flue 5 is the same everywhere.

[0043] Furthermore, a first guide member 6 is provided in the intermediate flue 5, which guides the airflow to deflect obliquely towards the first side along the first horizontal direction. The first guide member 6 can deflect obliquely towards the first side along the first horizontal direction, that is, in... Figure 1 The airflow is deflected to the left, thus guiding the airflow to deflect to the left. This adjusts the airflow after the turn so that it tends to flow more vertically upwards, reducing airflow in other directions and preventing or reducing the impact of the airflow carrying the desulfurization wastewater sprayed from the spray gun 2 onto the inner wall of the main body 1. The first guide component 6 adjusts the airflow before the rectifier component 3, which can further optimize the airflow direction.

[0044] Specifically, the first flow guide 6 includes a plurality of first flow guide plates stacked and spaced apart along the first horizontal direction. The upper end of each first flow guide plate is inclined relative to its lower end toward the first side to form a plurality of first flow guide channels inclined toward the first side. (Reference) Figure 1 As shown, the upper end of the first guide plate is inclined to the left, and a first guide channel with an outlet inclined to the left is formed between adjacent first guide plates. These first guide channels allow the flue gas flow, after entering and turning from the first side, to flow in the direction inclined to the first side, and gradually be adjusted to flow in the vertically upward direction. The first guide plates can be arranged at intervals along the first horizontal direction, and in the second horizontal direction perpendicular to the first horizontal direction, the two ends of the first guide plates are connected to the inner wall of the intermediate flue 5, thereby dividing a part of the intermediate flue 5 into multiple first guide channels. The first guide member 6 can be set at the inlet of the intermediate flue 5, and then the flow direction of the airflow is adjusted by the vertically upward extension of the downstream of the first guide member 6, so that the airflow tends to flow more in the vertically upward direction.

[0045] Furthermore, the drying tower includes a gradually expanding flue 8 connecting the intermediate flue 5 and the main body 1. The inlet cross-sectional dimension of the main body 1 is larger than the outlet cross-sectional dimension of the intermediate flue 5, and the cross-sectional dimension of the gradually expanding flue 8 gradually increases in the vertical direction. This gradual increase in the cross-sectional dimension of the gradually expanding flue 8 causes the pressure within the flue to gradually decrease, resulting in lower pressure and flow velocity of the flue gas reaching the main body 1 compared to the intermediate flue 5. By reducing the pressure and flow velocity of the flue gas, the flue gas flow becomes more gentle, preventing excessive mixing with the desulfurization wastewater sprayed from the spray gun 2, which could cause the desulfurization wastewater to collide with the inner wall of the main body 1.

[0046] The main body 1, the turning flue 4, the intermediate flue 5, and the gradually expanding flue 8 have rectangular cross-sections. The cross-section of the main body 1 remains consistent along the vertical direction, the cross-section of the intermediate flue 5 also remains consistent along the vertical direction, and the cross-sectional dimensions of the gradually expanding flue 8 increase along the vertical direction. This increase can be achieved by increasing the length and / or width, i.e., by increasing the dimensions in the first horizontal direction and / or the second horizontal direction.

[0047] The main body 1, the turning flue 4, the intermediate flue 5, and the gradually expanding flue 8 have the same dimensions in the second horizontal direction perpendicular to the first horizontal direction, and the dimensions of the gradually expanding flue 8 in the first horizontal direction gradually increase in the vertically upward direction.

[0048] Furthermore, a second flow guide 7 is disposed in the gradually expanding flue 8. The second flow guide 7 includes a plurality of second flow guide plates arranged in a stacked and spaced manner along the first horizontal direction. The second flow guide plates located on the first side of the centerline of the gradually expanding flue 8 along the first horizontal direction are respectively deflected to the first side, and the second flow guide plates located on the second side of the centerline of the gradually expanding flue 8 along the first horizontal direction are respectively deflected to the second side, thereby forming a second flow guide channel deflected from the center to both sides. (Reference) Figure 1 As shown, in the expanding flue 8, second guide plates are provided on both sides of its vertical centerline. The guide plate on the left (i.e., the first side) is inclined to the left, and the guide plate on the right (i.e., the second side) is inclined. These guide plates can guide the flue gas to flow from the center to both sides, thereby guiding the diffusion flow of the flue gas in the expanding flue 8. The second guide plates are arranged at intervals along the first horizontal direction, and their two ends in the second horizontal direction can be connected to the inner wall of the expanding flue 8 to form multiple second guide channels therein.

[0049] The drying tower includes a plurality of spray guns 2 arranged at intervals along the first horizontal direction and inserted into the body 1 along the second horizontal direction. The outlet of each spray gun 2 maintains a predetermined distance from the inner wall of the body 1. Figure 2 As shown, spray guns 2 are inserted from both sides of the body part 1 along a second horizontal direction and are spaced apart along a first horizontal direction, such that the outlets of the spray guns 2 are evenly arranged in the central region of the body part 1. The droplet size range of the spray guns 2 is no greater than 60 μm, preferably no greater than 40 μm. The spray angle of the spray guns 2 is no greater than 30°, preferably no greater than 20°. The flue gas velocity in the body part 1 is 6 m / s-12 m / s, preferably 7 m / s-9 m / s.

[0050] The rectifier 3 forms a plurality of rectifier channels with the same cross-section in the body portion 1. (Reference) Figure 3 As shown, the cross-section of the main body 1 is rectangular, and the rectifier 3 divides it to form multiple rectifier channels with rectangular cross-sections. Each rectifier channel has the same cross-section, so that the airflow can be more evenly distributed in the main body 1 through the rectification effect of the rectifier 3.

[0051] In addition, the inlet of the turning flue 4 is connected to a burner. The outlet of the burner can be horizontally oriented, that is, from the first side of the first horizontal direction to the second side, to connect to the inlet of the turning flue 4; the turning flue 4 is used to adjust the horizontally flowing flue gas from the burner to flow upward, so as to suit the arrangement of the spray gun 2 in the main body 1, and to facilitate the evaporation treatment of desulfurization wastewater.

[0052] In addition, the outlet of the main body 1 is connected to an outlet flue 9. The outlet flue 9 includes a vertically downward inlet and a horizontally oriented outlet, which can guide the airflow to be discharged horizontally. The discharged airflow can be treated by a dust collector to separate combustion product particles and crystalline particles after the desulfurization wastewater has been dried, thereby reducing the emission of waste particles.

[0053] Example

[0054] In this embodiment, the main body 1 has dimensions of 7000mm × 3400mm. The flow guides are respectively located downstream of the 90° transition flue and at the inlet of the gradually expanding flue, and respectively include a first flow guide plate and a second flow guide plate. The rectifier unit 3 has dimensions of 500*680*500mm. Figure 3 As shown, both the guide and rectifier components are made of stainless steel and fixed to the inner wall of the flue. Spray gun 2 is a solid cone-shaped atomizing spray gun with a spray angle not exceeding 20° and an atomized particle size not exceeding 40μm. Eight such guns are symmetrically arranged. Figure 2 As shown.

[0055] Among them, reference Figure 4 As shown, the tilt angles of the first deflector from left to right are 78°, 78°, 78°, and 79°, respectively; the tilt angles of the second deflector from left to right are 108°, 101°, 86°, and 78°, respectively.

[0056] Please refer to other dimensions of the evaporation tower. Figure 4 As shown, the length unit is mm.

[0057] In this embodiment, the average flue gas velocity inside the main body 1 is 7.1 m / s, and the flue gas temperature is 114°C. Each atomizing spray gun 2 sprays 250 L / h of desulfurization wastewater, for a total of 2000 L / h from all 8 spray guns, and the temperature of the desulfurization wastewater is approximately 50°C.

[0058] To demonstrate the function of the flow guiding and rectifying components within the evaporation tower, evaporation towers for desulfurization wastewater with and without flow guiding and rectifying components were tested respectively (reference). Figure 4 and Figure 5 The flow field was simulated as shown in the figure.

[0059] In particular, the flue gas velocity distribution in the evaporation tower without guides and rectifiers is uneven, such as... Figure 6 As shown, the left side of the evaporation tower has a lower velocity and a larger vortex, causing the atomized droplets to rotate within the tower. The droplet trajectory shows that some droplets move upstream of the atomizing nozzle, with the longest residence time reaching 4.3 seconds, and make contact with the tower wall as shown. Figure 8 and Figure 9 As shown. The evaporation tower, equipped with flow guides and rectifiers, exhibits a uniform velocity distribution within its main body 1, as shown. Figure 7 As shown, the flue gas flow direction is the same as the spray center direction of the atomizing spray gun 2. The maximum residence time of the atomized droplets in the body part 1 is about 2.0s. The droplets completely evaporate in the body part 1 without any wall collision or other phenomena. Figure 10 and Figure 11 As shown. In actual engineering operation, the evaporation rate of desulfurization wastewater met the design requirements, and no fouling, corrosion, or scaling was found on the walls of the main body 1 and the outlet flue 9, and there was no adverse impact on the downstream dust removal equipment.

[0060] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A drying tower for desulfurization wastewater, characterized in that, The evaporation tower includes a vertically extending body (1) capable of accommodating flue gas, a spray gun (2) disposed in the body (1) for spraying desulfurization wastewater, and a rectifier (3) disposed in the body (1) and located below the spray gun (2). The outlet of the spray gun (2) is oriented vertically upward. Multiple rectifier channels are formed in the rectifier (3) extending vertically and arranged horizontally, so that the airflow after passing through the rectifier (3) flows in a vertically upward direction. The rectifier (3) includes plates that are parallel to the vertical direction and intersecting horizontally and vertically; The drying tower includes a turning flue (4) and an intermediate flue (5) located upstream of the main body (1). The turning flue (4) has an inlet facing a first side in a first horizontal direction and an outlet facing upward in a vertical direction. The intermediate flue (5) is connected to the outlet of the turning flue (4). The intermediate flue (5) is provided with a first guide (6), which guides the airflow to deflect towards the first side along the first horizontal direction; The first guide member (6) includes a plurality of first guide plates stacked and spaced along the first horizontal direction, wherein the upper end of the first guide plate is deflected toward the first side relative to its lower end to form a plurality of first guide channels deflected toward the first side. The drying tower includes a gradually expanding flue (8) connecting the intermediate flue (5) and the main body (1). The inlet cross-sectional dimension of the main body (1) is larger than the outlet cross-sectional dimension of the intermediate flue (5). The cross-section of the gradually expanding flue (8) gradually increases in the vertical direction. The main body (1), the turning flue (4), the intermediate flue (5), and the gradually expanding flue (8) have the same dimensions in the second horizontal direction perpendicular to the first horizontal direction. The drying tower includes a plurality of spray guns (2) spaced apart along the first horizontal direction and inserted into the main body (1) along the second horizontal direction.

2. The evaporation tower for desulfurization wastewater according to claim 1, characterized in that, The cross-sections of the main body (1), the turning flue (4), the intermediate flue (5), and the gradually expanding flue (8) are rectangular.

3. The evaporation tower for desulfurization wastewater according to claim 2, characterized in that, The dimension of the gradually expanding flue (8) in the first horizontal direction gradually increases in the vertical upward direction.

4. The evaporation tower for desulfurization wastewater according to claim 3, characterized in that, The gradually expanding flue (8) is provided with a second guide member (7), which includes a plurality of second guide plates arranged in a stacked and spaced manner along the first horizontal direction. The second guide plates located on the first side of the center line of the gradually expanding flue (8) along the first horizontal direction are respectively deflected to the first side, and the second guide plates located on the second side of the center line of the gradually expanding flue (8) along the first horizontal direction are respectively deflected to the second side, thereby forming a second guide channel that deflects from the center to both sides.

5. The evaporation tower for desulfurization wastewater according to claim 4, characterized in that, The outlet of the spray gun (2) is kept at a predetermined distance from the inner wall of the main body (1).

6. The evaporation tower for desulfurization wastewater according to claim 4, characterized in that, The rectifier (3) forms a plurality of rectifier channels with the same cross-section in the body part (1).

7. The evaporation tower for desulfurization wastewater according to claim 1, characterized in that, The inlet of the turning flue (4) is connected to a burner.

8. The evaporation tower for desulfurization wastewater according to any one of claims 1-7, characterized in that, The outlet of the main body (1) is connected to an outlet flue (9).

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