A flue gas purification system and production line for industrial silicon smelting

Abstract

This invention addresses the problem in existing flue gas dust removal technologies where optimal dust removal efficiency is achieved only at filtration velocities below 0.45 m / min. Higher filtration velocities lead to increased resistance in the fiberglass filter bag system, hindering the removal of fly ash. This invention provides a flue gas purification system and production line for industrial silicon smelting. Specifically, it relates to the field of flue gas desulfurization, denitrification, and dust removal technology for industrial silicon DC and AC furnaces. The system includes a primary waste heat boiler, a filter dust collector, metal filter bags, a denitrification device, a secondary waste heat boiler, a dust removal drive device, and a wet desulfurization tower. The filter dust collector's filtration velocity is set at 0.87 m / min. The outlet flue of the denitrification device passes through the dust collector housing to improve waste heat recovery efficiency. The dust removal drive device employs a three-dimensional flow fan. The filter dust collector uses metal filter bags, and its filtration velocity can reach 0.87 m / min.

Description

Technical Field

[0001] This utility model relates to the field of flue gas desulfurization, denitrification and dust removal technology for industrial silicon DC furnaces and AC furnaces, and in particular to a flue gas purification system and production line for industrial silicon smelting. Background Technology

[0002] The industrial silicon smelting process generates a large amount of high-temperature, dusty flue gas. If this flue gas is emitted directly without effective treatment, it will cause serious environmental pollution, including particulate matter pollution and acid gas pollution in the air, affecting the surrounding air quality and ecological balance, endangering human health, and potentially causing corrosion and damage to nearby buildings and vegetation.

[0003] In existing flue gas purification processes for industrial silicon smelting, the optimal dust removal effect is achieved when the filtration velocity in the dust removal stage is below 0.45 m / min. If the filtration velocity is too high, it will lead to high resistance in the fiberglass filter bag system, making it impossible to remove the dust. At a filtration velocity of 0.45 m / min, dust removal can only be performed on flue gas with a flow rate of 240,000 Nm³ / h. Utility Model Content

[0004] This invention addresses the problem that in existing technologies, the optimal dust removal effect can only be achieved when the filtration velocity in the flue gas dust removal stage is below 0.45 m / min. If the filtration velocity is too high, it will lead to high resistance in the fiberglass filter bag system and the inability to remove soot. This invention provides a flue gas purification system and production line for industrial silicon smelting.

[0005] The technical solution adopted in this utility model is:

[0006] A flue gas purification system for industrial silicon smelting includes:

[0007] A primary waste heat boiler is used to receive the flue gas discharged from the electric arc furnace (AC / DC) and perform primary waste heat recovery on the flue gas discharged from the electric arc furnace (AC / DC). The flue gas flow rate discharged from the electric arc furnace (AC / DC) is 340,000 Nm³ / h, the temperature is 500℃, the dust concentration in the flue gas is 6g / m³-10g / m³, and the temperature of the flue gas after primary waste heat recovery is 280℃-420℃.

[0008] Nm³ / h is called the standard flow rate (Nm³ / h is defined this way throughout the text); under standard conditions, that is, when the temperature is 0℃ (273.15K) and the pressure is 1 standard atmosphere (101.325kPa), the volume of the gas is called Nm³ (standard volume), and N represents the standard condition.

[0009] The filter dust collector removes dust from the flue gas after primary waste heat recovery using metal filter bags. The particulate matter concentration in the flue gas after dust removal is below 10 mg / m³. The filtration velocity of the filter dust collector is set to 0.87 m / min.

[0010] The denitrification device contains a honeycomb catalyst, which is used to perform SCR denitrification on the dust-removed flue gas.

[0011] The second-stage waste heat boiler is used to receive the flue gas after denitrification and perform secondary waste heat recovery on the flue gas. The temperature of the flue gas after secondary waste heat recovery is below 150℃.

[0012] Wet desulfurization tower is used to receive flue gas after secondary waste heat recovery and perform wet desulfurization on it to generate purified flue gas.

[0013] The dust removal drive unit is installed between the secondary waste heat boiler and the wet desulfurization tower; the wind speed of the dust removal drive unit determines the filtration wind speed of the filter dust collector.

[0014] Furthermore, the metal material in the metal filter bag is 316L stainless steel.

[0015] Furthermore, the outlet flue of the denitrification unit passes through the dust collector housing to improve waste heat recovery efficiency.

[0016] Furthermore, the dust removal drive unit adopts a three-dimensional flow fan.

[0017] Based on the same inventive concept, this utility model also provides an industrial silicon production line, which includes a submerged arc furnace and the aforementioned flue gas purification system.

[0018] Based on the same inventive concept, this utility model also provides an industrial silicon production line, which includes a submerged arc furnace and the aforementioned flue gas purification system.

[0019] The beneficial effects of this utility model are:

[0020] This utility model discloses a flue gas purification system and production line for industrial silicon smelting. The dust collector uses metal filter bags, achieving a filtration velocity of up to 0.87 m / min, solving the problem of relatively low filtration velocities in existing technologies, which can only be set below 0.45 m / min. This increased filtration velocity allows for dust removal from flue gas with a flow rate as high as 340,000 Nm³ / h and a dust concentration of 6 g / m³-10 g / m³ (the particulate matter concentration in the dust-removed flue gas is below 10 mg / m³). Furthermore, the number of filter bags is correspondingly reduced, and the system's floor space is also decreased. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 Schematic diagram of a flue gas purification system for industrial silicon smelting;

[0023] Figure 2 This is a schematic diagram showing the location relationship between the filter dust collector, the denitrification device, and the outlet flue of the denitrification device. Detailed Implementation

[0024] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0025] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this invention.

[0026] The embodiments of the utility model will now be described in detail with reference to the accompanying drawings.

[0027] This embodiment discloses a flue gas purification system for industrial silicon smelting. The system includes a primary waste heat boiler 1, a dust collector 2, metal filter bags, a denitrification device 3, a secondary waste heat boiler 4, a dust removal drive device 5, and a wet desulfurization tower 6. In addition to the complete structure of this system, this embodiment also provides an external system: a submerged arc furnace (AC / DC) 7. (See attached diagram) Figure 1 As shown.

[0028] A waste heat boiler 1 is used to receive the flue gas discharged from the electric arc furnace 7 and perform primary waste heat recovery on the flue gas discharged from the electric arc furnace 7; wherein, the flue gas flow rate discharged from the electric arc furnace 7 is 340000 Nm³ / h, the temperature is 500℃, the flue gas dust concentration is 6g / m³-10g / m³, and the flue gas temperature after primary waste heat recovery is 280℃-420℃;

[0029] Nm³ / h is called the standard flow rate; under standard conditions, i.e., when the temperature is 0℃ (273.15K) and the pressure is 1 standard atmosphere (101.325kPa), the volume of the gas is called Nm³ (standard volume), where N represents the standard condition.

[0030] The filter dust collector 2 removes dust from the flue gas after primary waste heat recovery using metal filter bags; the filtration velocity of the filter dust collector 2 is set to 0.87 m / min.

[0031] The filtration velocity of the filter dust collector 2 is determined by the velocity of the dust removal drive device 5.

[0032] The denitrification device 3 contains a honeycomb catalyst, and the denitrification device 3 uses the honeycomb catalyst to perform SCR denitrification on the flue gas after dust removal;

[0033] The second-stage waste heat boiler 4 is used to receive the denitrified flue gas and perform secondary waste heat recovery on the denitrified flue gas. The temperature of the flue gas after secondary waste heat recovery is below 150℃.

[0034] The wet desulfurization tower 6 is used to receive the flue gas after secondary waste heat recovery and perform wet desulfurization on it to generate purified flue gas.

[0035] The dust removal drive unit 5 is installed between the secondary waste heat boiler 4 and the wet desulfurization tower 6.

[0036] Specifically, the metal material in the metal filter bag is 316L stainless steel. 316L stainless steel possesses excellent corrosion resistance, oxidation resistance, and thermal stability. It can withstand high-temperature flue gas of 280℃-420℃ after a single waste heat recovery, maintaining structural stability and mechanical strength under high-temperature conditions. This prevents the filter bag from failing due to thermal deformation or melting, ensuring long-term, efficient dust removal.

[0037] Specifically, the outlet flue 31 of the denitrification unit 3 passes through the dust collector housing to improve waste heat recovery efficiency. (See attached diagram) Figure 2 As shown.

[0038] Specifically, the dust removal drive unit 5 adopts a three-dimensional flow fan, which plays an energy-saving role.

[0039] The working principle of the flue gas purification system for industrial silicon smelting disclosed in this embodiment is as follows:

[0040] Step 1: The waste heat boiler 1 receives the flue gas discharged from the electric arc furnace 7 and performs a waste heat recovery process on the flue gas discharged from the electric arc furnace 7.

[0041] Step 2: The flue gas after the first waste heat recovery enters the filter dust collector 2. The filter dust collector 2 removes dust from the flue gas after the first waste heat recovery through metal filter bags. The particulate matter concentration of the flue gas after dust removal is below 10mg / m³. The filtration velocity of the filter dust collector is set to 0.87m / min by adjusting the three-dimensional flow fan.

[0042] Step 3: The flue gas after dust removal enters the denitrification unit 3 for SCR denitrification; the denitrification efficiency can reach 90%-95%.

[0043] Step 4: The denitrified flue gas enters the secondary waste heat boiler 4 for secondary waste heat recovery; at this time, the flue gas temperature will drop below 150℃.

[0044] Step 5: The flue gas after the second-stage waste heat recovery enters the wet desulfurization tower 6 for wet desulfurization, generating purified flue gas. The desulfurization efficiency can reach over 95%.

[0045] Tests showed that the particulate matter concentration in the purified flue gas was ≤10mg / m³, and the NO content was ≤10mg / m³. x The outlet emission concentration is <20mg / Nm³, and the SO2 outlet concentration is ≤15mg / Nm³.

[0046] In the flue gas purification system for industrial silicon smelting disclosed in this embodiment, the dust collector 2 uses metal filter bags, and the wind speed of the dust removal drive device 5 can reach 0.87 m / min, solving the problem that the filtration wind speed in the prior art can only be set below 0.45 m / min. The increased filtration wind speed in this system allows for dust removal of flue gas flow rates up to 340,000 Nm³ / h (with particulate matter concentration in the flue gas after dust removal below 10 mg / m³). In addition, the number of filter bags is correspondingly reduced, and the system's floor space is also reduced. In this system, the outlet flue 31 of the denitrification device 3 passes through the dust collector housing, improving the waste heat recovery efficiency of the secondary waste heat boiler 4 and enhancing the overall waste heat recovery efficiency of the system. The use of a three-dimensional flow fan in this system reduces energy consumption.

[0047] Based on the same inventive concept, this embodiment also provides an industrial silicon production line, which includes a submerged arc furnace and the aforementioned flue gas purification system.

[0048] Based on the same inventive concept, this embodiment also provides an industrial silicon production line, which includes a submerged arc furnace and the aforementioned flue gas purification system.

Claims

1. A flue gas purification system for industrial silicon smelting, characterized in that, include: A primary waste heat boiler is used to receive flue gas discharged from a submerged arc furnace (AC / DC) and to perform primary waste heat recovery on the flue gas discharged from the submerged arc furnace (AC / DC). A dust collector that removes dust from flue gas after primary waste heat recovery using metal filter bags; A denitrification device, wherein the denitrification device contains a honeycomb catalyst, and the denitrification device performs SCR denitrification on the dust-removed flue gas through the honeycomb catalyst; The second-stage waste heat boiler is used to receive the denitrified flue gas and perform secondary waste heat recovery on the denitrified flue gas. A wet desulfurization tower is used to receive flue gas after secondary waste heat recovery and perform wet desulfurization on it to generate purified flue gas. A dust removal drive device is installed between the second-stage waste heat boiler and the wet desulfurization tower.

2. The flue gas purification system according to claim 1, characterized in that, in, The metal filter bag is made of 316L stainless steel.

3. The flue gas purification system according to claim 1, characterized in that, The outlet flue of the denitrification device passes through the dust collector housing to improve waste heat recovery efficiency.

4. The flue gas purification system according to claim 1 or 2, characterized in that, The dust removal drive device uses a three-dimensional flow fan.

5. An industrial silicon production line, characterized in that, It includes a submerged arc furnace and a flue gas purification system as described in any one of claims 1-4.

6. An industrial silicon production line, characterized in that, It includes a submerged arc furnace and a flue gas purification system as described in any one of claims 1-4.

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