Full-closed ferroalloy electric furnace flue gas treatment system and treatment method

Abstract

The invention relates to the technical field of flue gas treatment, and provides a full-closed ferroalloy electric furnace flue gas treatment system and method.The treatment system comprises a ferroalloy electric furnace, a flue gas purification system, a scatter dust removal system and a waste flue gas direct discharge flue, and the ferroalloy electric furnace communicates with the waste flue gas direct discharge flue; the ferroalloy electric furnace is communicated with a flue gas purification system through a flue gas purification flue, an upper pneumatic butterfly valve and a lower pneumatic butterfly valve are arranged on the waste flue gas direct discharge flue, an electric gate valve is arranged on the flue gas purification flue, and a branch flue and a coal gas concentration analyzer are arranged on the waste flue gas direct discharge flue between the upper pneumatic butterfly valve and the lower pneumatic butterfly valve. The branch flue is communicated with the scatter dust removal system, an electric glasses valve is arranged on the branch flue, and the gas concentration analyzer is electrically connected with the electric glasses valve. The existing conventional configuration of a fully-closed ferroalloy electric furnace manufacturer is utilized, and corresponding connection, control, detection and safety interlocking devices are configured, so that seamless conversion and butt joint among the three devices are realized to solve the dilemma problems.

Description

Technical Field

[0001] The present application belongs to the technical field of flue gas treatment, and more specifically, to a fully enclosed ferroalloy electric furnace flue gas treatment system and treatment method. Background Art

[0002] In the production process of fully enclosed ferroalloy electric furnace, the flue gas produced must be treated and discharged in compliance with the standards. In normal production process, the flue gas produced by the fully enclosed ferroalloy electric furnace is treated by the supporting flue gas purification system.

[0003] However, in the production process of ferroalloy electric furnaces, the following five abnormal (or special) situations are often encountered: First, when the electric furnace is newly opened to bake electrodes, the purification system cannot be used normally or smoke is discharged, which does not meet the standards; second, when the flue gas (coal gas) purification system fails and cannot be put into operation normally, the flue gas cannot be processed or smoke is discharged; third, when the electric furnace equipment fails and needs to be shut down for inspection or repair; fourth, when the power grid is limited to low-load production or the electric furnace process requires low-load baking of electrodes and the local ambient temperature is low (such as Inner Mongolia Autonomous Region, dozens of degrees below zero in winter), the low-temperature flue gas is prone to condensation and blockage when it is processed by the purification system, and it cannot operate normally; fifth, when the user equipment at the back end of the clean coal gas fails and the coal gas cannot be used. Whenever the fully enclosed ferroalloy electric furnace production encounters the above five abnormal special situations, there will be a "dilemma" that the flue gas cannot meet the emission standards when the power is transmitted and produced, and normal production cannot be achieved if the emission standards are not met, while the requirements of environmental protection policies and regulations are "production without smoke, and smoke without production". Therefore, how to solve the "dilemma" is a technical problem that fully enclosed ferroalloy electric furnace manufacturers urgently need to solve. Summary of the invention

[0004] In response to the "dilemma" problem in the above-mentioned prior art, the purpose of the embodiments of the present application is to provide a fully enclosed ferroalloy electric furnace flue gas treatment system, which utilizes the existing conventional configuration of the fully enclosed ferroalloy electric furnace manufacturer's electric furnace raw flue gas direct discharge flue, flue gas purification system and scattered-point dust removal system for flue gas treatment in front of the furnace for iron casting operations, and is configured with corresponding connection, control, detection and safety interlocking devices to achieve seamless conversion and docking among the three to solve these "dilemma" problems.

[0005] To achieve the above-mentioned purpose, the technical solution adopted in the present application is: to provide a fully enclosed ferroalloy electric furnace flue gas treatment system, including: a ferroalloy electric furnace, a flue gas purification system, a scattered-point dust removal system and a direct exhaust duct for wild smoke, the ferroalloy electric furnace is connected to the direct exhaust duct for wild smoke, the ferroalloy electric furnace and the flue gas purification system are connected through the flue gas purification duct, the direct exhaust duct for wild smoke is provided with an upper pneumatic butterfly valve and a lower pneumatic butterfly valve at intervals, the flue gas purification duct is provided with an electric gate valve, the direct exhaust duct for wild smoke between the upper pneumatic butterfly valve and the lower pneumatic butterfly valve is connected to a branch flue and a gas concentration analyzer, the branch flue is connected to the scattered-point dust removal system, the branch flue is provided with an electric glasses valve, and the gas concentration analyzer is electrically interlocked with the electric glasses valve.

[0006] In one embodiment, the ferroalloy electric furnace is provided with an electrical interlock switch electrically interlocked with the electric glasses valve. When the furnace door of the ferroalloy electric furnace is fully opened, the electrical interlock switch is triggered, and the electrical interlock switch then energizes the electric glasses valve.

[0007] In one embodiment, a manual gate valve is also provided on the flue gas purification flue.

[0008] Another object of the present application is to provide a fully enclosed ferroalloy electric furnace flue gas treatment method, based on the fully enclosed ferroalloy electric furnace flue gas treatment system as described above, the treatment method includes two flue gas treatment states, one is that the electric furnace flue gas is converted from the flue gas purification system to the scattered point dust removal system for treatment, and the other is that the electric furnace flue gas is converted from the scattered point dust removal system to the flue gas purification system for treatment;

[0009] The operation steps of converting the flue gas from the flue gas purification system to the scattered dust removal system are as follows:

[0010] A1. Reduce the load of the ferroalloy electric furnace to the lowest level or cut off the power supply;

[0011] A2. The flue gas purification system continues to operate for 5 minutes to 15 minutes;

[0012] A3. Open the upper pneumatic butterfly valve and the lower pneumatic butterfly valve on the direct exhaust flue of uncultivated smoke;

[0013] A4. Close the electric gate valve on the flue gas purification flue;

[0014] A5. Stop the flue gas purification system and purge the flue gas purification system with nitrogen;

[0015] A6. Open the door of the ferroalloy electric furnace, open the door to the right position and connect the control box of the electric glasses valve to the power supply;

[0016] A7. The gas concentration analyzer detects the CO concentration in the direct exhaust flue. When the CO concentration is lower than 7%, the gas operator in the central control room can obtain the operation authority to supply power to the electric eyeglass valve;

[0017] A8. Start the fan of the scattered-point dust removal system, and the operating frequency is 20HZ. The gas inspector operates the control box of the electric glasses valve on site to open the electric glasses valve.

[0018] A9. Close the upper pneumatic butterfly valve on the direct exhaust duct for unburned smoke; the smoke generated by the ferroalloy electric furnace enters the scattered point dust removal system through the direct exhaust duct for unburned smoke and the branch flue for treatment;

[0019] The operation steps of converting the flue gas from the scattered dust removal system to the flue gas purification system are as follows:

[0020] B1. Open the upper pneumatic butterfly valve on the direct exhaust flue of wild smoke;

[0021] B2. Stop the fan of the scattered dust removal system;

[0022] B3. The gas inspector operates the control box of the electric glasses valve on site to close the electric glasses valve;

[0023] B4. Close the door of the ferroalloy electric furnace;

[0024] B5. Start the fan of the flue gas purification system, and the operating frequency is 5HZ;

[0025] B6. The gas inspector accepts the instruction of the gas operator in the central control room and slowly closes the lower pneumatic butterfly valve on the direct exhaust flue of raw smoke according to the furnace pressure, and opens the electric gate valve on the flue gas purification flue at the same time;

[0026] B7. After the docking is completed, the fan frequency of the flue gas purification system is adjusted according to the load of the ferroalloy electric furnace and the furnace pressure. The flue gas generated by the ferroalloy electric furnace enters the flue gas purification system through the flue gas purification flue for treatment.

[0027] In one embodiment, in step A6, at least three furnace doors are opened.

[0028] In one embodiment, in step A6, the electrical interlock switch provided at the furnace door rotating mechanism of the ferroalloy electric furnace will be triggered only when the furnace door is fully opened. After the electrical interlock switch is triggered, the control box of the electric glasses valve can be powered on.

[0029] The fully enclosed ferroalloy electric furnace flue gas treatment system and treatment method provided in this application have the following beneficial effects:

[0030] By utilizing the existing conventionally configured flue gas discharge ducts for direct discharge of raw flue gas from electric furnaces, flue gas purification systems, and scattered-point dust removal systems for flue gas treatment during iron-making and pouring operations in front of the furnace, and configuring corresponding connection, control, detection, and safety interlocking devices, these "dilemmas" can be solved by achieving seamless conversion and docking among the three. This can solve the problem of failure to meet emission standards and power supply during the production process of fully enclosed ferroalloy electric furnaces due to the inability to treat flue gas, and thus the inability to supply electricity for production. This can effectively solve the difficulties encountered in equipment failure handling and the implementation of various process measures during the production process, streamline the production process, and ensure that the implementation of various process and equipment maintenance measures taken during the production process complies with the requirements of environmental protection and safety laws and regulations. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A simplified connection diagram of a fully enclosed ferroalloy electric furnace flue gas treatment system provided in an embodiment of the present application.

[0033] Among them, the reference numerals in the figure are:

[0034] 1. Ferroalloy electric furnace; 2. Flue gas purification system; 3. Scattered dust removal system; 4. Direct exhaust flue for wild smoke; 5. Flue gas purification flue; 6. Upper pneumatic butterfly valve; 7. Lower pneumatic butterfly valve; 8. Electric gate valve; 9. Branch flue; 10. Gas concentration analyzer; 11. Electric glasses valve; 12. Electrical interlock switch; 13. Furnace door; 14. Manual gate valve. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0036] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0037] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] like Figure 1 As shown, a fully enclosed ferroalloy electric furnace flue gas treatment system provided in an embodiment of the present application is now described. The fully enclosed ferroalloy electric furnace flue gas treatment system comprises: a ferroalloy electric furnace 1, a flue gas purification system 2, a scattered point dust removal system 3 and a direct exhaust flue 4 for wild smoke, wherein the ferroalloy electric furnace 1, the flue gas purification system 2, the scattered point dust removal system 3 and the direct exhaust flue 4 for wild smoke are all existing equipment in the factory, and their specific structures are not described in detail here.

[0040] In this embodiment, the purpose is to organically combine the ferroalloy electric furnace 1, the flue gas purification system 2, the scattered dust removal system 3 and the direct exhaust flue 4 for wild smoke. Specifically, the ferroalloy electric furnace 1 is connected to the direct exhaust flue 4 for wild smoke, and the ferroalloy electric furnace 1 is connected to the flue gas purification system 2 through the flue gas purification flue 5. The direct exhaust flue 4 for wild smoke is provided with an upper pneumatic butterfly valve 6 and a lower pneumatic butterfly valve 7 at intervals, and the flue gas purification flue 5 is provided with an electric gate valve 8. The direct exhaust flue 4 for wild smoke between the upper pneumatic butterfly valve 6 and the lower pneumatic butterfly valve 7 is connected to a branch flue 9 and a gas concentration analyzer 10. The gas concentration analyzer 10 is used to detect the content of flue gas CO in the direct exhaust flue 4 for wild smoke, and the branch flue 9 is connected to the scattered dust removal system 3, and an electric eyeglass valve 11 is provided on the branch flue 9. Among them, the opening and closing of the electric glasses valve 11 is associated with a safety interlock device, wherein the safety interlock device includes a gas concentration analyzer 10 and an electrical interlock switch 12 arranged on the ferroalloy electric furnace 1; the gas concentration analyzer 10 is electrically interlocked with the electric glasses valve 11, and the electrical interlock switch 12 is electrically interlocked with the electric glasses valve 11; the electrical interlock switch 12 will be triggered only when the furnace door 13 of the ferroalloy electric furnace 1 is fully opened, and the electrical interlock switch 12 will then energize the control box of the electric glasses valve 11, and only when the CO content in the sampling analysis result of the gas concentration analyzer 10 reaches a specified control value (less than 7%) lower than the explosive concentration of the mixed gas (CO content 12.4%), can the electric glasses valve 11 be opened and closed through the control box. A manual gate valve 14 is also provided on the flue gas purification flue 5, which is normally open. When the electric gate valve 8 is abnormal and needs to be repaired, the flue gas purification flue 5 can be opened and closed through the manual gate valve 14.

[0041] In this embodiment, a flue gas treatment method for a fully enclosed ferroalloy electric furnace 1 is also provided. Based on the fully enclosed ferroalloy electric furnace flue gas treatment system as described above, the treatment method includes two flue gas treatment states, one is that the electric furnace flue gas is converted by the flue gas purification system 2 to be treated by the scattered point dust removal system 3, and the other is that the electric furnace flue gas is converted by the scattered point dust removal system 3 to be treated by the flue gas purification system 2;

[0042] The operation steps of converting the flue gas from the flue gas purification system 2 to the scattered dust removal system 3 are as follows:

[0043] A1. Reduce the load of the ferroalloy electric furnace to the lowest level or cut off the power supply;

[0044] A2, flue gas purification system 2 continues to operate for 5 minutes to 15 minutes;

[0045] A3. Open the upper pneumatic butterfly valve 6 and the lower pneumatic butterfly valve 7 on the direct exhaust flue 4;

[0046] A4. Close the electric gate valve 8 on the flue gas purification flue 5;

[0047] A5. Stop the flue gas purification system 2 and purge the flue gas purification system 2 with nitrogen;

[0048] A6. When the furnace pressure reaches a certain negative pressure value, open the furnace door 13 of the ferroalloy electric furnace to allow the furnace gas to fully burn and reduce the CO concentration; open the furnace door 13 to the right position to connect the control box of the electric glasses valve 11 to the power supply;

[0049] A7. The gas concentration analyzer 10 detects the CO concentration in the direct exhaust flue 4. When the CO concentration is lower than 7%, the gas operator in the central control room can obtain the operation authority to supply power to the electric eyeglass valve 11.

[0050] A8. Start the fan of the scattered dust removal system 3, and the working frequency is 20HZ. The gas inspector operates the control box of the electric glasses valve 11 on site to open the electric glasses valve 11;

[0051] A9. Close the upper pneumatic butterfly valve 6 on the direct exhaust flue 4; the flue gas generated by the ferroalloy electric furnace 1 enters the scattered dust removal system 3 through the direct exhaust pipe and the branch flue 9 for treatment. When the scattered dust removal system 3 is used for flue gas treatment, the flue gas purification system 2 is in a shutdown state. At this time, the flue gas purification system 2 can be inspected, maintained, cleaned, etc. to ensure that the flue gas purification system 2 can be used normally in the future.

[0052] The operation steps of converting the electric furnace flue gas from the scattered point dust removal system 3 to the flue gas purification system 2 are as follows:

[0053] B1. Open the upper pneumatic butterfly valve 6 on the direct exhaust flue 4;

[0054] B2. Stop the fan of scattered-point dust removal system 3;

[0055] B3. The gas inspector operates the control box of the electric glasses valve 11 on site to close the electric glasses valve 11;

[0056] B4, closing the furnace door 13 of the ferroalloy electric furnace 1;

[0057] B5. Start the fan of the flue gas purification system 2, and the operating frequency is 5HZ;

[0058] B6. The gas inspector accepts the instruction from the gas operator in the central control room and slowly closes the lower pneumatic butterfly valve 7 on the direct exhaust flue 4 of the raw smoke according to the furnace pressure, and at the same time opens the electric gate valve 8 on the flue gas purification flue 5;

[0059] B7. After the docking is completed, the fan frequency of the flue gas purification system 2 is adjusted according to the load and furnace pressure of the ferroalloy electric furnace 1. The flue gas generated by the ferroalloy electric furnace 1 enters the flue gas purification system 2 through the flue gas purification flue 5 for treatment.

[0060] In this embodiment, in step A6, the furnace door 13 is opened at least three times to ensure that the gas in the furnace is fully burned to reduce the CO concentration. In step A6, the electrical interlock switch 12 disposed at the furnace door rotating mechanism (such as near the hinge) on the ferroalloy electric furnace 1 is triggered only when the furnace door 13 is fully opened. After the electrical interlock switch 12 is triggered, the control box of the electric glasses valve 11 is powered on. The electrical interlock switch 12 and the gas concentration detector cooperate with each other to control the opening and closing of the electric glasses valve 11 to ensure safety.

[0061] In actual processes, the processing system and processing method provided in this embodiment have been applied to two 30000KVA fully enclosed ferroalloy electric furnaces 1 (submerged arc furnaces) of Wukuanghutie Inner Mongolia Ferroalloy Co., Ltd. Practice has proved that this processing system and processing method can effectively solve the aforementioned "dilemma" problems encountered in the production process, streamline the production process, and provide convenience and possibility for equipment failure handling and the implementation of process methods and measures in the production process, thereby eliminating the occurrence of environmental violations in the production process, effectively promoting the smooth progress of the production process, and achieving good results in promoting production, so that the company's production process fully complies with the requirements of national environmental protection policies and regulations; and the use effect is good, substantially generating good production benefits and social benefits, and effectively promoting the company's production.

[0062] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A fully enclosed ferroalloy electric furnace flue gas treatment system, comprising: A ferroalloy electric furnace (1), a flue gas purification system (2), a scattered-point dust removal system (3) and a direct exhaust duct for wild smoke (4), characterized in that the ferroalloy electric furnace (1) is connected to the direct exhaust duct for wild smoke (4), the ferroalloy electric furnace (1) and the flue gas purification system (2) are connected via a flue gas purification duct (5), an upper pneumatic butterfly valve (6) and a lower pneumatic butterfly valve (7) are arranged on the direct exhaust duct for wild smoke (4), an electric gate valve (8) is arranged on the flue gas purification duct (5), a branch flue (9) and a gas concentration analyzer (10) are connected to the direct exhaust duct for wild smoke (4) between the upper pneumatic butterfly valve (6) and the lower pneumatic butterfly valve (7), the branch flue (9) is connected to the scattered-point dust removal system (3), an electric eyeglass valve (11) is arranged on the branch flue (9), and the gas concentration analyzer (10) is electrically interlocked with the electric eyeglass valve (11).

2. The fully enclosed ferroalloy electric furnace flue gas treatment system according to claim 1, characterized in that: The ferroalloy electric furnace (1) is provided with an electrical interlock switch (12) which is electrically interlocked with the electric glasses valve (11). When the furnace door (13) of the ferroalloy electric furnace (1) is fully opened, the electrical interlock switch (12) is triggered, and the electrical interlock switch (12) then energizes the electric glasses valve (11).

3. The fully enclosed ferroalloy electric furnace flue gas treatment system according to claim 2, characterized in that: The flue gas purification flue (5) is also provided with a manual gate valve (14).

4. A method for treating flue gas from a fully enclosed ferroalloy electric furnace (1), based on the fully enclosed ferroalloy electric furnace flue gas treatment system as claimed in any one of claims 1 to 3, characterized in that: The treatment method includes two flue gas treatment states, one is that the electric furnace flue gas is converted from the flue gas purification system (2) to the scattered point dust removal system (3) for treatment, and the other is that the electric furnace flue gas is converted from the scattered point dust removal system (3) to the flue gas purification system (2) for treatment; The operation steps of converting the flue gas of the electric furnace from the flue gas purification system (2) to the scattered dust removal system (3) are as follows: A1. Reduce the load of the ferroalloy electric furnace (1) to the lowest level or shut down the power; A2. The flue gas purification system (2) continues to operate for 5 minutes to 15 minutes; A3. Open the upper pneumatic butterfly valve (6) and the lower pneumatic butterfly valve (7) on the direct flue gas exhaust duct (4); A4. Close the electric gate valve (8) on the flue gas purification flue (5); A5. Stop the flue gas purification system (2), and purge the flue gas purification system (2) with nitrogen; A6. Open the furnace door (13) of the ferroalloy electric furnace (1) until the furnace door (13) is fully opened and the control box of the electric eyeglass valve (11) is powered on; A7. The gas concentration analyzer (10) detects the CO concentration in the direct exhaust flue (4). When the CO concentration is lower than 7%, the gas operator in the central control room can obtain the operation authority to supply power to the electric eyeglass valve (11); A8. Start the fan of the scattered dust removal system (3) at a working frequency of 20 Hz. The gas inspector operates the control box of the electric glasses valve (11) on site to open the electric glasses valve (11); A9, close the upper pneumatic butterfly valve (6) on the direct exhaust duct (4) for raw smoke; the smoke generated by the ferroalloy electric furnace (1) enters the scattered point dust removal system (3) through the direct exhaust duct for raw smoke and the branch duct (9) for treatment; The operation steps of converting the electric furnace flue gas from the scattered point dust removal system (3) to the flue gas purification system (2) are as follows: B1. Open the upper pneumatic butterfly valve (6) on the direct exhaust flue (4); B2. Stop the fan of the scattered dust removal system (3); B3, the gas inspector operates the control box of the electric glasses valve (11) on site to close the electric glasses valve (11); B4, closing the furnace door (13) of the ferroalloy electric furnace (1); B5. Start the fan of the flue gas purification system (2) at a frequency of 5 Hz; B6. The gas inspector accepts the instruction from the gas operator in the central control room and slowly closes the lower pneumatic butterfly valve (7) on the direct exhaust flue (4) of the raw smoke according to the furnace pressure, and at the same time opens the electric gate valve (8) on the flue gas purification flue (5); B7. After the docking is completed, the fan frequency of the flue gas purification system (2) is adjusted according to the load of the ferroalloy electric furnace (1) and the furnace pressure. The flue gas generated by the ferroalloy electric furnace (1) enters the flue gas purification system (2) through the flue gas purification flue (5) for treatment.

5. The fully enclosed ferroalloy electric furnace flue gas treatment system according to claim 4, characterized in that: In step A6, at least three of the furnace doors (13) are opened.

6. The fully enclosed ferroalloy electric furnace flue gas treatment system according to claim 4, characterized in that: In step A6, the electrical interlock switch (12) provided at the furnace door rotating mechanism of the ferroalloy electric furnace (1) will be triggered only when the furnace door (13) is fully opened. After the electrical interlock switch (12) is triggered, the control box of the electric glasses valve (11) can be powered on.

Images