A wet dust removal system for recovering zinc suboxide from flue gas

Abstract

The application develops a wet dust removal system for recycling zinc suboxide in flue gas, which directly communicates the first liquid discharge port at the bottom of the venturi dust collector with the thickener through a pipeline and a liquid discharge pump; a middle liquid discharge port is arranged at the middle position of the venturi dust collector, the middle liquid discharge port is connected with a circulating pipe, a second circulating pump is arranged on the circulating pipe, and the circulating pipe is connected with a second liquid supplement pipe; a conical liquid collecting device is arranged at the bottom of the spray mixing chamber, a second liquid discharge port is arranged at the bottom of the conical liquid collecting device, a slurry discharge pipe is connected with the second liquid discharge port, and the end of the slurry discharge pipe is connected with a dust slurry tank; the above arrangement can effectively reduce the slurry concentration at the bottom of the venturi dust collector, reduce the circulating slurry concentration in the circulating pipe and the frequency of stopping and dredging, greatly improve the effective working time of the wet dust removal system, and effectively ensure the working efficiency of the kivcett furnace and the processing efficiency of the high-temperature slag.

Description

Technical Field

[0001] This invention relates to the field of flue gas treatment technology in pyrometallurgical lead smelting furnaces, specifically a wet dust removal system for recovering zinc oxide from flue gas. Background Technology

[0002] In the Kifset furnace pyrometallurgical lead smelting process, a large amount of high-temperature zinc-containing slag is generated. To improve resource utilization, this high-temperature slag needs to be treated in a fuming furnace to recover the metal elements. The process principle of the fuming furnace is as follows: the fuming process is essentially a reduction and volatilization process. A mixture of pulverized coal and air is blown into the liquid high-temperature slag inside the fuming furnace, causing the lead and zinc oxides in the slag to be reduced into lead and zinc vapors. Lead oxide and lead sulfide, which have higher vapor pressures, can also volatilize directly in compound form. The metal vapors, metal sulfides, and oxides enter the upper space of the furnace along with the flue gas, where they are re-oxidized into lead oxide and zinc oxide by specially added air. These are then collected in a dust collection device and recovered as secondary zinc oxide products. During operation, the fuming furnace must be kept under negative pressure to prevent flue gas leakage.

[0003] At this point, it is necessary to collect and recycle the dust in the flue gas. In our existing process, we use a wet dust collection system for dust collection, such as... Figure 1 As shown:

[0004] The main body of the wet dust removal system is a Venturi dust collector 1. A spray mixing chamber 2 is connected to the side of the Venturi dust collector 1. A flue gas inlet 3 is located at the top of the spray mixing chamber 2. A flue gas outlet 4 is located at the top of the Venturi dust collector 1. The middle part of the Venturi dust collector 1 is connected to the first replenishment pipe 5. The bottom of the Venturi dust collector 1 is the first drain outlet 6. The main drain pipe 8 is connected to the first drain outlet 6. A first circulation pump 7 is installed on the main drain pipe 8. The main drain pipe 8 is connected to the circulation pipe 9 and the drain branch pipe 11. The end of the circulation pipe 9 is connected to the atomizer inlet pipe 10. The atomizer inlet pipe 10 is connected to the atomizer, and the atomizer is located in the spray mixing chamber 2. The end of the drain branch pipe 11 is connected to the dust slurry tank 12.

[0005] The working principle of the above-mentioned wet dust removal system is as follows:

[0006] After the flue gas enters the spray mixing chamber, it collides with the atomized droplets and gains weight. Then it enters the Venturi dust collector, where the atomized droplets and dust settle to form a slurry. This slurry is discharged through the first drain port. Part of it flows back to the spray mixing chamber through the circulation pipe, where it is atomized by the atomizer and absorbs dust again. The other part is discharged into the dust slurry tank through the drain branch pipe. The function of the first replenishment pipe is to replenish and dilute the slurry at the bottom of the Venturi dust collector to prevent the slurry from becoming too concentrated.

[0007] However, in practice, the aforementioned wet dust removal system has three major problems:

[0008] 1. The main drain pipe is connected to the circulation pipe and the branch drain pipe respectively, resulting in low pressure, low flow rate and slow velocity of the circulating slurry in the circulation pipe. The atomizer is easily blocked, affecting the atomization efficiency and dust collection efficiency. Similarly, the low pressure, low flow rate and slow velocity in the branch drain pipe make the slurry very easy to clump and block the first drain port.

[0009] 2. Inside the spray mixing chamber, some atomized droplets and dust settle to form a slurry. This slurry has a very high concentration and is very easy to clump and stick in the spray mixing chamber, blocking the flue gas passage and affecting the flue gas flow. Once the flue gas flow is affected, it directly affects the negative pressure state inside the fuming furnace. At this time, it is necessary to stop the machine and clear the spray mixing chamber.

[0010] 3. As the dust in the slurry at the bottom of the Venturi dust collector slowly agglomerates and gradually blocks the first drain port, the slurry level in the Venturi dust collector begins to rise. At this time, it is necessary to adjust the first replenishment pipe and reduce the replenishment volume to ensure the slurry level in the Venturi dust collector. At this time, the concentration of the slurry in the Venturi dust collector increases, and the agglomeration speed of the dust in the slurry accelerates. Moreover, when replenishing through the first replenishment pipe, due to the high concentration and large mass of the slurry at the bottom and the low concentration and small mass of the slurry at the top, it is difficult to directly dilute the slurry at the bottom. This causes the concentration of the circulating slurry in the circulation pipe to keep rising, which further increases the concentration of the slurry settling in the spray mixing chamber. This is extremely detrimental to ensuring the flue gas flow rate and the negative pressure state in the fuming furnace.

[0011] If the flue gas flow rate is significantly affected, disrupting the negative pressure state inside the fuming furnace, the furnace must be shut down to clear the spray mixing chamber. At the same time, the fuming furnace must also be stopped, which will affect the working efficiency of the Kifset furnace and the processing efficiency of high-temperature slag. Summary of the Invention

[0012] This invention develops a wet dust removal system for recovering zinc oxide from flue gas. The system connects the first drain port at the bottom of the Venturi dust collector directly to a thickener via a pipe and a drain pump. A central drain port is located in the middle of the Venturi dust collector and connected to a circulation pipe. A second circulation pump is installed on the circulation pipe, which is connected to a second replenishment pipe. A conical liquid collection device is located at the bottom of the spray mixing chamber, with a second drain port at its bottom. A slurry discharge pipe is connected to the second drain port, and the end of the slurry discharge pipe is connected to a dust slurry tank. This configuration effectively reduces the slurry concentration at the bottom of the Venturi dust collector, lowers the circulating slurry concentration in the circulation pipe, and reduces the frequency of shutdowns for cleaning. This significantly increases the effective working time of the wet dust removal system, effectively ensuring the working efficiency of the Kifset furnace and the processing efficiency of high-temperature slag.

[0013] A wet dust removal system for recovering zinc oxide from flue gas, the main body of the wet dust removal system being a Venturi dust collector 1, with a spray mixing chamber 2 connected to its side, a flue gas inlet 3 at the top of the spray mixing chamber 2, and a flue gas outlet 4 at the top of the Venturi dust collector 1; a first replenishment pipe 5 is connected to the middle of the Venturi dust collector 1, and a first drain port 6 is located at the bottom of the Venturi dust collector 1, which is directly connected to a thickener 14 via a pipe and a drain pump 13; a central... The middle drain port 15 is connected to the circulation pipe 9. The circulation pipe 9 is equipped with a second circulation pump 17 and is connected to the second replenishment pipe 16. The end of the circulation pipe 9 is connected to the atomizer inlet pipe 10. The atomizer inlet pipe 10 is connected to the atomizer, and the atomizer is located in the spray mixing chamber 2. The bottom of the spray mixing chamber 2 is equipped with a conical liquid collection device. The bottom of the conical liquid collection device has a second drain port 18. The slurry discharge pipe 19 is connected to the second drain port 18. The end of the slurry discharge pipe 19 is connected to the dust slurry tank 12.

[0014] Advantages of this invention:

[0015] 1. The circulation pipe of the present invention has a second replenishment pipe to replenish the liquid, which directly reduces the concentration of circulating slurry in the circulation pipe; moreover, there is no drain pipe occupying the pressure of the second circulation pump, the circulating slurry pressure in the circulation pipe is high, the flow rate is high, and the flow velocity is fast, the atomizer is not easily blocked, ensuring atomization efficiency and dust collection efficiency, while reducing the concentration of slurry settling in the spray mixing chamber.

[0016] 2. The high concentration of slurry settling inside the spray mixing chamber is collected by the cone-shaped slurry collection device and directly discharged into the dust slurry tank through the slurry discharge pipe, which helps to reduce the concentration of slurry at the bottom of the Venturi dust collector and effectively reduces the concentration of circulating slurry in the circulation pipe.

[0017] 3. The first drain port is connected to the drain pump and directly discharges the slurry into the thickener. Since the drain pump does not need to be connected to the circulation pipe, the drain pump has a high discharge pressure and a fast flow rate, and the first drain port is not easy to be blocked. Moreover, when the first drain port begins to show signs of blockage, the concentration of the slurry at the bottom of the Venturi dust collector can be adjusted by speeding up the discharge and speeding up the replenishment.

[0018] 4. The middle drain port of this invention is relatively high, allowing the slurry with low concentration and small mass at the top to enter the circulation pipe; the slurry (with higher concentration) at the bottom of the Venturi dust collector is directly discharged to the thickener, which can effectively reduce the slurry concentration at the bottom of the Venturi dust collector. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a wet dust removal system for background technology.

[0020] Figure 2 This is a schematic diagram of the wet dust removal system of the present invention;

[0021] In the diagram: 1-Venturi dust collector; 2-Spray mixing chamber; 3-Flue gas inlet; 4-Flue gas outlet; 5-First replenishment pipe; 6-First drain outlet; 7-First circulation pump; 8-Main drain pipe; 9-Circulation pipe; 10-Atomizer inlet pipe; 11-Drainage branch pipe; 12-Dust slurry tank; 13-Drain pump; 14-Thickener; 15-Middle drain outlet; 16-Second replenishment pipe; 17-Second circulation pump; 18-Second drain outlet; 19-Slurry discharge pipe. Detailed Implementation

[0022] Example 1

[0023] like Figure 2 As shown, a wet dust removal system for recovering zinc oxide from flue gas comprises a Venturi dust collector 1 as its main component. A spray mixing chamber 2 is connected to the side of the Venturi dust collector 1, and a flue gas inlet 3 is located at the top of the spray mixing chamber 2. A flue gas outlet 4 is located at the top of the Venturi dust collector 1. A first replenishment pipe 5 is connected to the middle of the Venturi dust collector 1, and a first drain outlet 6 is located at the bottom of the Venturi dust collector 1. The first drain outlet 6 is directly connected to a thickener 14 via a pipe and a drain pump 13. A central drain is located in the middle of the Venturi dust collector 1. The liquid outlet 15 is connected to the circulation pipe 9, and the circulation pipe 9 is equipped with a second circulation pump 17. The circulation pipe 9 is connected to the second replenishment pipe 16. The end of the circulation pipe 9 is connected to the atomizer inlet pipe 10, and the atomizer inlet pipe 10 is connected to the atomizer. The atomizer is located in the spray mixing chamber 2. The bottom of the spray mixing chamber 2 is equipped with a conical liquid collection device. The bottom of the conical liquid collection device has a second liquid outlet 18. The slurry discharge pipe 19 is connected to the second liquid outlet 18, and the end of the slurry discharge pipe 19 is connected to the dust slurry tank 12.

[0024] The working principle of the above-mentioned wet dust removal system is as follows:

[0025] After the flue gas enters the spray mixing chamber, it collides with the atomized droplets and becomes heavier. Part of the settled slurry is discharged into the dust slurry tank through the second drain port and slurry discharge pipe. Then it enters the Venturi dust collector, where the atomized droplets and dust settle to form slurry. The bottom slurry is discharged to the thickener through the first drain port, while the slurry with a higher liquid level returns to the spray mixing chamber through the middle drain port and circulation pipe. The function of the first replenishment pipe is to replenish and dilute the slurry at the bottom of the Venturi dust collector to prevent the slurry from becoming too concentrated. The function of the second replenishment pipe is to replenish the circulation pipe to further reduce the concentration of the circulating slurry in the circulation pipe.

[0026] In our background technology, the average downtime and unblocking cycle of the wet dust removal system is 5.6 days. After improving the wet dust removal system according to the above embodiments, the average downtime and unblocking cycle of the wet dust removal system is 18.5 days.

[0027] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wet dust removal system for recovering zinc oxide from flue gas, characterized in that: The main body of the wet dust removal system is a Venturi dust collector. A spray mixing chamber is connected to the side of the Venturi dust collector, with a flue gas inlet at the top and a flue gas outlet at the top of the Venturi dust collector. The middle of the Venturi dust collector is connected to a first replenishment pipe, and the bottom of the Venturi dust collector is a first drain outlet, which is directly connected to a thickener via a pipe and a drain pump. A central drain outlet is located in the middle of the Venturi dust collector and is connected to a circulation pipe. A second circulation pump is installed on the circulation pipe, which is connected to a second replenishment pipe. The end of the circulation pipe is connected to an atomizer inlet pipe, which is connected to the atomizer, which is located within the spray mixing chamber. A conical liquid collection device is located at the bottom of the spray mixing chamber, with a second drain outlet at the bottom of the conical liquid collection device. A slurry discharge pipe is connected to the second drain outlet, and the end of the slurry discharge pipe is connected to a dust slurry tank.

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