Oxidation air flotation device for desulfurizing tower

Abstract

The utility model provides an oxidation air floatation device for a desulfurizing tower, which belongs to the technical field of environment-friendly and energy-saving equipment and comprises a slurry tank and an absorption tower positioned above the slurry tank, a valve is communicated with the outer side of the bottom of the slurry tank through a pipeline I, the valve is communicated with a micro-nano generator through a pipeline II, and the micro-nano generator is communicated with the absorption tower through a pipeline II. The micro-nano generator is communicated with a circulating pump through a pipeline III, and the output end of the circulating pump is communicated with one end of a circulating slurry channel. The utility model solves the problems that the utilization rate of oxidation air is low, the spatial distribution of the oxidation air in the slurry box is non-uniform, the energy consumption of the oxidation fan is high, the surplus bubbles of the blown oxidation air cannot play a role in removing oil stains in slurry by air flotation, and the oxidation device cannot be overhauled on line after going wrong and must be overhauled by stopping the tower.

Description

Technical Field

[0001] The utility model belongs to the technical field of environmental protection and energy-saving equipment, and particularly relates to an oxidation flotation device for a desulfurization tower. Background Art

[0002] During the purification process of the roasting furnace flue gas, the flue gas is first led out through the outlet flue and enters the tempering tower. After being sprayed and cooled, it enters the electric tar precipitator to remove the tar after cooling and condensation. Then, the pressure is increased by the induced draft fan and the flue gas enters the desulfurization tower and wet electrolysis to remove sulfur, fluorine, dust and other pollutants in the flue gas. Finally, it is discharged into the atmosphere through the chimney after meeting the standards.

[0003] Desulfurization typically utilizes a limestone / lime-gypsum wet flue gas desulfurization process. In this process, the desulfurization tower typically utilizes a conventional countercurrent spray absorber. The spray absorber's primary function is to remove sulfur dioxide from the flue gas and produce gypsum as a saleable or disposable byproduct. The spray absorber is divided into three sections: from bottom to top: a slurry tank, a flue gas absorption zone, and a demisting zone. The slurry tank primarily stores the desulfurizer slurry (composed of limestone / lime, some calcium sulfate, and calcium sulfite), oxidizes the calcium sulfite, and crystallizes the gypsum. The flue gas absorption zone extends from the upper portion of the slurry tank to the topmost spray layer, where the flue gas comes into contact with the desulfurization slurry to complete SO2 absorption. The demisting zone, located above the absorber's spray layer, removes entrained liquid droplets from the flue gas, transforming it into clean flue gas before exiting the desulfurization tower.

[0004] The slurry tank is located at the bottom of the absorption tower. One of its primary functions is to oxidize calcium sulfite and produce gypsum crystals. In the slurry tank, calcium sulfite, a direct product of desulfurization, is forcibly oxidized into calcium sulfate, which crystallizes as gypsum (CaSO₄·2H₂O). The oxidation reaction is accomplished by introducing oxidizing air into the slurry tank at appropriate locations. This air is blown into the slurry tank from outside the tower by a dedicated oxidation blower system. Currently, most oxidizing air is introduced into the absorption tower through air distribution pipes and air spray guns.

[0005] The two existing methods of introducing oxidizing air, whether air distribution pipes or air spray guns, both have the following disadvantages:

[0006] 1. The utilization rate of oxidation air is low, the spatial distribution of oxidation air in the slurry box is uneven, and the energy consumption of the oxidation fan is high;

[0007] Theoretically, the O2 / SO2 molar ratio required for complete oxidation is 0.5. However, in actual operation, the O2 / SO2 molar ratio of the above-mentioned oxidation device is within the range of 1.25 to 1.5. This is because the two air addition methods mentioned above produce millimeter-sized bubbles with a small specific surface area, which are easy to aggregate and grow. They rise rapidly in the slurry, have a short residence time, and are unevenly distributed in the space throughout the slurry tank (especially in the air spray gun). Therefore, in order to meet the needs of complete oxidation, the amount of air input must be increased, resulting in an oxidation air utilization rate of only 33%, and preferably no more than 40%. The excess air input also increases the power consumption of the oxidation blower.

[0008] 2. The oxidized air bubbles blown in cannot play the role of "flotation" to remove the oil stains in the slurry;

[0009] The flue gas from the carbon anode roasting furnace contains harmful substances such as asphalt tar, fluoride, and dust. Although it is purified by an electric tar precipitator at the front end, some residual tar will be sprayed and washed off in the desulfurization tower and enter the slurry. The possible consequences are a decrease in the desulfurization slurry's ability to absorb SO2 or even "poisoning" of the slurry, difficulty in dehydration by the vacuum belt conveyor, and a decrease in gypsum quality.

[0010] Generally speaking, the flotation process involves introducing air into an oil-containing slurry, generating tiny bubbles. This causes the oil in the slurry to adhere to the air bubbles and rise to the surface along with them, forming an oil float. This oil can then be removed through external discharge. The smaller the bubble diameter and the greater the number of bubbles, the better the flotation effect. However, the two aforementioned air addition methods produce millimeter-sized bubbles with a small specific surface area. These bubbles tend to aggregate, rise rapidly within the slurry, and have a short residence time. Although more than 90% of the oxidized air by volume rises and is discharged from the slurry, flotation generally fails to effectively remove oil.

[0011] 3. When a problem occurs in the oxidation device, it cannot be repaired online and the tower must be shut down for maintenance.

[0012] Whether it is the air distribution pipe or the air spray gun, air pipe breakage and scaling blockage may occur during operation. When such problems occur, because the oxidation device is located within the slurry in the slurry tank, the desulfurization tower can only be stopped and the slurry in the slurry tank must be drained before inspection and maintenance can be carried out.

[0013] In order to solve the above problems, an oxidation flotation device for a desulfurization tower is proposed. Utility Model Content

[0014] The utility model provides an oxidation flotation device for a desulfurization tower, which aims to solve the problems of low oxidation air utilization, uneven spatial distribution of oxidation air in a slurry box, high energy consumption of an oxidation fan, inability of excess bubbles in the blown oxidation air to "float" and remove oil stains in the slurry, and inability to perform online maintenance when a problem occurs in the oxidation device, requiring the tower to be stopped for maintenance.

[0015] An embodiment of the present utility model provides an oxidation flotation device for a desulfurization tower, comprising a slurry tank and an absorption tower located above the slurry tank, wherein the outer side of the bottom of the slurry tank is connected to a valve via a pipe 1, the valve is connected to a micro-nano generator via a pipe 2, the micro-nano generator is connected to a circulation pump via a pipe 3, the output end of the circulation pump is connected to one end of a circulating slurry channel, a spray layer is installed in the absorption tower, the micro-nano generator is connected to an oxidation blower via a pipe 4, a stirring assembly is installed on the outer side of the slurry tank, a plurality of stirring assemblies are provided and are evenly distributed in a circle on the slurry tank, an overflow port located above the stirring assembly is installed on the outer side of the slurry tank, a raw flue gas inlet channel is installed above the slurry tank, and a clean flue gas discharge channel is installed on the top of the absorption tower.

[0016] Furthermore, the spraying layer comprises a spraying pipe, and a plurality of evenly distributed spray heads are installed at the bottom of the spraying pipe.

[0017] By adopting the above technical solution, the slurry and the nozzle are connected by a spraying pipe, so that the slurry can be sprayed out for reaction, and the slurry containing micro-nano bubbles can be sprayed more comprehensively, achieving uniform distribution over the entire cross section.

[0018] Furthermore, the input end of the spraying layer is communicated with the circulating slurry channel.

[0019] By adopting the above technical solution, the circulating slurry channel passes the slurry containing micro-nano bubbles into the spraying layer.

[0020] Furthermore, the stirring assembly includes a mounting platform installed on the side wall of the slurry tank, a motor is fixedly connected to the mounting platform, a rotating rod is fixedly connected to the output end of the motor, and a plurality of stirring blades are fixedly connected to one end of the rotating rod extending into the slurry tank.

[0021] By adopting the above technical solution, the motor is used to drive the rotating rod and the stirring blade to rotate, so as to stir the desulfurization slurry. Since the oxidizing air blowing method is adopted, the stirring component does not need to participate in the gas dispersion, so the energy consumption of the stirring component is also reduced accordingly, and the stirring power per unit volume of slurry is reduced from 80w / m3 to 50w / m3.

[0022] Furthermore, the rotating rod is rotatably connected to the slurry box and the mounting platform.

[0023] By adopting the above technical solution, the rotating rod serves as a transmission member connected to the rotating rod, and power can be transmitted.

[0024] Furthermore, the overflow port is arranged at a position slightly lower than the liquid level in the slurry tank.

[0025] By adopting the above technical solution, the overflow port can be used to separate oil and dirt, and the discharged oily wastewater can be further treated.

[0026] Furthermore, water is introduced into the spray channel through an external water pump.

[0027] By adopting the above technical solution, SO2 in the flue gas can be removed, thereby converting the flue gas into clean flue gas to be discharged from the absorption tower and washing away the scale.

[0028] The beneficial effects of the utility model are:

[0029] 1. The utility model can effectively reduce the amount of oxidation air used, so that the oxidation air is evenly distributed in the tower, thereby greatly improving the utilization rate of oxidation air and reducing the energy consumption of the oxidation fan.

[0030] 2. The utility model adopts the oxidizing air blowing method, so the stirring component does not need to participate in gas dispersion, so the energy consumption of the stirring component is also reduced accordingly.

[0031] 3. The utility model can not only effectively utilize the oxidizing air, but also utilize the excess oxidizing air to realize the flotation oil removal in the slurry tank.

[0032] 4. In the present invention, the micro-nano bubble generator and its circulating slurry pipeline are arranged outside the slurry tank. Therefore, no matter if there is a problem with the equipment body or the connecting pipeline, online maintenance can be achieved without stopping the operation of the absorption tower.

[0033] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0035] Figure 1 This is a schematic structural diagram of an embodiment of the present utility model;

[0036] Figure numerals: 1. slurry tank; 2. valve; 3. micro-nano generator; 4. circulation pump; 5. oxidation fan; 6. circulating slurry channel; 7. spray layer; 8. overflow port; 91. mounting platform; 92. motor; 93. rotating rod; 94. stirring blade; 10. raw flue gas inlet channel; 11. clean flue gas exhaust channel; 12. demister; 13. spray channel; 14. spray head; 15. absorption tower. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the technical solution of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the specific embodiments of the present invention. The same figure marks in the drawings represent the same parts. It should be noted that the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Reference Figure 1 The embodiment of the utility model proposes an oxidation flotation device for a desulfurization tower, comprising a slurry tank 1 and an absorption tower 15 located above the slurry tank 1. The rear end of the slurry tank 1 is fixedly connected to a circulating pipe circulating slurry channel 6. The bottom outer side of the slurry tank 1 is connected to a valve 2 through a pipe 1. The valve 2 is connected to a micro-nano generator 3 through a pipe 2. The micro-nano generator 3 is connected to a circulation pump 4 through a pipe 3. The output end of the circulation pump 4 is connected to one end of the circulating slurry channel 6. A spray layer 7 is installed in the absorption tower 15. The micro-nano generator 3 is connected to an oxidation blower 5 through a pipe 4. The inner wall of the absorption tower 15 is fixedly connected to a demister 12, which is installed above the spray layer 7. Spray channels 13 are installed on the upper and lower sides of the demister 12. Several spray heads 14 are installed on the side of the two spray channels 13 close to the demister 12. A stirring assembly is installed on the outside of the slurry tank 1. There are multiple stirring assemblies that are evenly distributed in a circle on the slurry tank 1. An overflow port 8 located above the stirring assembly is installed on the outside of the slurry tank 1. A raw flue gas inlet channel 10 is installed above the slurry tank 1, and a clean flue gas exhaust channel 11 is installed on the top of the absorption tower 15.

[0039] The spraying layer 7 includes a spraying pipe, and a number of evenly distributed nozzles are installed at the bottom of the spraying pipe. The slurry and the nozzles are connected by the spraying pipe, so that the slurry can be sprayed out and reacted. The slurry containing micro-nano bubbles can be sprayed more comprehensively, achieving uniform distribution over the entire cross-section.

[0040] The input end of the spraying layer 7 is communicated with the circulating slurry channel 6, and the circulating slurry channel 6 passes the slurry containing micro-nano bubbles into the spraying layer.

[0041] The stirring assembly includes a mounting platform 91 installed on the side wall of the slurry tank 1, and a motor 92 is fixedly connected to the mounting platform 91. The output end of the motor 92 is fixedly connected to a rotating rod 93, and one end of the rotating rod 93 extending into the slurry tank 1 is fixedly connected to a plurality of stirring blades 94. The operation of the motor 92 drives the rotating rod 93 and the stirring blades 94 to rotate to stir the desulfurization slurry. Since the oxidizing air blowing method is adopted, the stirring assembly does not need to participate in gas dispersion, so the energy consumption of the stirring assembly is also reduced accordingly, and the stirring power per unit volume of slurry is reduced from 80w / m3 to 50w / m3.

[0042] The rotating rod 93 is rotatably connected to the slurry box 1 and the mounting platform 91. The rotating rod 93 serves as a transmission member connected to the rotating rod 93 and can transmit power.

[0043] The overflow port 8 is arranged at a position slightly lower than the liquid level in the slurry tank 1. The overflow port 8 can be used to separate oil and dirt, and the discharged oily wastewater can be further processed.

[0044] Water is introduced into the spray channel 13 through an external water pump, which can remove SO2 from the flue gas and turn it into clean flue gas to be discharged from the absorption tower 15, washing away the scale;

[0045] The utility model adopts micro-nano bubble technology. Micro-nano bubbles refer to bubbles with a diameter between tens of microns and hundreds of nanometers when bubbles occur. This type of bubble is between micron bubbles and nano bubbles and has the following physical and chemical properties.

[0046] 1. Large specific surface area

[0047] According to the surface area formula, the specific surface area of a 10-micron bubble is theoretically 100 times that of a 1-millimeter bubble. This increases the contact area between air and liquid by 100 times, and the speed of various reactions also increases by 100 times.

[0048] 2. Slow rising speed

[0049] According to Stokes' law, the speed at which a bubble rises in water is proportional to the square of its diameter. The smaller the bubble diameter, the slower it rises. A bubble with a diameter of 1 mm rises in water at a speed of 6 m / min, while a bubble with a diameter of 10 microns rises at a speed of 3 mm / min—1 / 2000 of the former.

[0050] 3. High gas solubility rate

[0051] Micro-nano bubbles have the characteristics of slow rising speed and self-pressurized dissolution, which makes the micro-nano bubbles gradually shrink to nanometer level during the slow rising process, and finally disappear and dissolve into water, thereby greatly improving the solubility of gas in water.

[0052] Since the micro-nano generator 3 and its circulation pipeline 6 are arranged outside the slurry tank 1, no matter if there is a problem with the equipment body or the connecting pipeline, it can be repaired online without stopping the operation of the absorption tower.

[0053] The specific implementation method is as follows: when in use, the user puts desulfurization slurry into the slurry box 1. Under the extraction of the circulation pump 4, the slurry enters the micro-nano generator 3 through the valve 2. At the same time, the other path of the micro-nano generator 3 is oxidation air, which is blown in by the oxidation blower 5. After the gas and liquid phases are mixed inside the micro-nano generator 3, the output is a slurry containing micro-nano bubbles. The oxidation reaction of the slurry occurs immediately when the gas and liquid phases are mixed. The oxidation reaction is expanded in space and time. The slurry containing micro-nano bubbles is driven by the circulation pump 4, passes through the circulation slurry channel 6, and then is sprayed out through multiple spray heads and returns to the slurry box 1. Then, it falls to the upper end of the slurry by gravity, achieving uniform distribution on the entire cross-section. This reciprocating cycle is repeated. Due to the characteristics of the micro-nano bubbles, the amount of oxidation air blown in can be reduced by more than half. Therefore, the utilization rate of the oxidation air is increased to more than 66%, so that the energy consumption of the oxidation fan 5 can be reduced. Then, the motor 92 is started to drive the rotating rod 93 and the stirring blade 94 to operate to fully stir the desulfurization slurry. Since the oxidation air blowing method is adopted, the stirring component does not need to participate in the gas dispersion, so the energy consumption of the stirring component is also reduced accordingly. Similarly, due to the characteristics of micro-nano bubbles, a large number of fine bubbles in the slurry cause the air to attach to the oil particles in the form of highly dispersed tiny bubbles, resulting in a state where the density of the oil particles is less than that of the slurry. The buoyancy principle is used to make them float on the surface of the slurry, and the oil separation can be achieved through the overflow port 8, so that it can be discharged for further treatment. The demister 12 can remove the droplets entrained in the flue gas, thereby converting it into clean flue gas and discharging it from the desulfurization tower through the clean flue gas exhaust channel 11, which is more practical.

[0054] Taking an open roaster with an annual production capacity of 300,000 tons as an example, the flue gas flow rate is 295,000 Nm3 / h, the SO2 concentration is 1000 mg / m3, and the slurry pool volume is 300 m3. The main technical parameters of the conventional oxidation system and the utility model are compared as follows:

[0055]

[0056] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in this invention is defined by the appended claims and their equivalents.

Claims

1. An oxidation flotation device for a desulfurization tower, comprising a slurry tank (1) and an absorption tower (15) located above the slurry tank (1), characterized in that: The bottom outer side of the slurry tank (1) is connected to a valve (2) through a pipe 1, the valve (2) is connected to a micro-nano generator (3) through a pipe 2, the micro-nano generator (3) is connected to a circulation pump (4) through a pipe 3, the output end of the circulation pump (4) is connected to one end of a circulating slurry channel (6), a spray layer (7) is installed in the absorption tower (15), the micro-nano generator (3) is connected to an oxidation blower (5) through a pipe 4, a stirring assembly is installed on the outer side of the slurry tank (1), the stirring assembly is provided in plurality and is evenly distributed in a ring shape on the slurry tank (1), an overflow port (8) located above the stirring assembly is installed on the outer side of the slurry tank (1), a raw flue gas inlet channel (10) is installed above the slurry tank (1), and a clean flue gas discharge channel (11) is installed at the top of the absorption tower (15).

2. The oxidation flotation device for a desulfurization tower according to claim 1, characterized in that: The spraying layer (7) comprises a spraying pipeline, and a plurality of spray heads evenly distributed are installed at the bottom of the spraying pipeline.

3. The oxidation flotation device for a desulfurization tower according to claim 2, characterized in that: The input end of the spraying layer (7) is communicated with the circulating slurry channel (6).

4. The oxidation flotation device for a desulfurization tower according to claim 1, characterized in that: The stirring assembly comprises a mounting platform (91) mounted on the side wall of the slurry tank (1), a motor (92) being fixedly connected to the mounting platform (91), a rotating rod (93) being fixedly connected to the output end of the motor (92), and a plurality of stirring blades (94) being fixedly connected to one end of the rotating rod (93) extending into the absorption tower slurry tank (1).

5. The oxidation flotation device for a desulfurization tower according to claim 4, characterized in that: The rotating rod (93) is rotatably connected to the slurry box (1) and the mounting platform (91).

6. The oxidation flotation device for a desulfurization tower according to claim 1, characterized in that: The overflow port (8) is arranged at a position slightly lower than the liquid level in the slurry tank (1).

7. The oxidation flotation device for a desulfurization tower according to claim 1, characterized in that: The spraying channel (13) is fed with spraying water via an external water pump.

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