Combustion system for shaft furnace for directly manufacturing rods from recycled copper

Abstract

The invention discloses a combustion system for a shaft furnace for direct rod manufacturing through recycled copper, and relates to the field of recycled copper machining, the combustion system comprises the shaft furnace, a combustion unit, a staged heat cycle air supply unit and a temperature control feedback unit, the combustion unit comprises at least three double-swirl combustors, the three double-swirl combustors are arranged around the furnace wall of the shaft furnace, and the temperature control feedback unit is arranged on the double-swirl combustors. The multiple sets of combustion units are distributed in the height direction of the shaft furnace, a conical opening is formed in the top end of the shaft furnace, the top end of the conical opening communicates with an exhaust pipe, the exhaust pipe is provided with a heat exchanger, gradient heating is achieved through the stratified combustion design, raw materials are preheated through the upper combustion unit, and the heat load of the lower combustion unit is reduced; and the contact area of flames and the raw materials is increased through the double-rotational-flow combustion technology, the heat transfer efficiency is improved, and the time from feeding to melting of the raw materials is shortened.

Description

Technical Field

[0001] This invention relates to the field of recycled copper processing, and in particular to a combustion system for a vertical shaft furnace for direct rod making of recycled copper. Background Technology

[0002] The direct rod-making process using recycled copper involves pre-treating scrap copper and then directly feeding it into a vertical shaft furnace for smelting. Copper rods are then produced through continuous casting and rolling. This technology boasts advantages such as a short process flow, low energy consumption, and minimal pollution. The vertical shaft furnace, as the core equipment of this process, directly impacts the quality of copper smelting, energy consumption levels, and environmental indicators. Currently, the combustion systems of vertical shaft furnaces for direct rod-making using recycled copper still suffer from numerous technical deficiencies, hindering the full realization of the process's advantages.

[0003] Existing vertical shaft furnace combustion systems mostly use single-channel burners, resulting in insufficient fuel-air mixing, low combustion efficiency (typically ≤85%), and significant fuel waste. Simultaneously, the flame shape is uncontrollable, easily leading to localized high temperatures or uneven temperature distribution. Temperature fluctuations in the vertical shaft furnace's constant-temperature zone can reach ±20℃ or more, causing uneven copper liquid composition, high oxidation loss rate, and affecting the quality of copper rod products.

[0004] Therefore, it is necessary to propose a combustion system for a shaft furnace for direct rod making of recycled copper to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a combustion system for a vertical shaft furnace for direct rod production from recycled copper. This system addresses the problems of existing vertical shaft furnace combustion systems, which often employ single-channel burners, resulting in insufficient fuel-air mixing, low combustion efficiency (typically ≤85%), and significant fuel waste. Furthermore, the flame shape is uncontrollable, easily leading to localized high temperatures or uneven temperature distribution. Temperature fluctuations in the furnace's constant-temperature zone can reach ±20℃ or more, causing uneven copper composition, high oxidation loss, and negatively impacting the quality of the copper rods.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a combustion system for a vertical shaft furnace for direct rod making of recycled copper, comprising a vertical shaft furnace and a combustion unit, a staged hot air circulation supply unit and a temperature control feedback unit, wherein the combustion unit comprises at least three dual swirl burners arranged around the furnace wall of the vertical shaft furnace, and multiple sets of combustion units are arranged, with the multiple sets of combustion units distributed along the height direction of the vertical shaft furnace;

[0007] The top of the vertical furnace is provided with a conical opening, the top of which is connected to an exhaust pipe. A heat exchanger is provided on the exhaust pipe. The heat exchanger and the staged thermal circulation air supply system are connected through a heat exchange pipe. The staged thermal circulation air supply system is connected to a dual swirl burner.

[0008] An inner sleeve is fixed to the inner wall of the vertical furnace. The inner sleeve has a frustum-shaped opening inside, and the bottom radius of the frustum-shaped opening is smaller than the top radius.

[0009] Preferably, the combustion port of the dual swirl burner is inclined downward, and the dual swirl burner is provided with nested inner swirl channels and outer swirl channels.

[0010] Preferably, the staged heat circulation air supply unit includes a primary air module, a secondary air module, and an air heat exchanger. The primary air module is connected to the inner vortex channel through an independent pipe, and the secondary air module, the heat exchanger, and the outer vortex channel are connected in sequence.

[0011] Preferably, the temperature control feedback unit includes an infrared thermometer, a PLC controller, and an actuator. The infrared thermometer is installed at the top and bottom of the vertical furnace to directly collect the temperature data inside the furnace. The infrared thermometer is connected to the PLC controller, the PLC controller is connected to the actuator, and the actuator is connected to the staged heat circulation air supply unit.

[0012] Preferably, the inner swirl channel of the dual swirl burner has a diameter of 80mm-150mm, and the outer swirl channel has a diameter of 150mm-300mm. Adjustable guide vanes are provided at the outlets of both the inner and outer swirl channels, with the vane angle adjustable from 15° to 45°. Each dual swirl burner has a built-in ignition electrode and a dual-band flame detector. The breakdown voltage of the ignition electrode is 8kV-15kV, and the response time of the flame detector is ≤0.5s.

[0013] Preferably, the primary air module of the staged air-heat circulation air supply unit is equipped with a high-pressure centrifugal fan with a primary air velocity of 15m / s-25m / s, the secondary air module is equipped with a variable frequency axial flow fan with a secondary air velocity of 20m / s-35m / s, and the heat exchanger uses a finned tube air-heat exchanger with a heat exchange efficiency of ≥85%.

[0014] Preferably, the inner sleeve is provided with multiple buffer mechanisms, each including a rotating shaft and an elastic baffle. The rotating shaft is rotatably connected to the inner wall of the vertical furnace, and the elastic baffle is fixed to the outside of the rotating shaft.

[0015] Preferably, a feed inlet is provided on one side of the conical opening, and a box door is provided on the feed inlet.

[0016] Preferably, a filter screen plate is provided at the bottom of the vertical furnace, a waste discharge port is connected to one side of the vertical furnace and is located above the filter screen plate, and a copper discharge port is connected to the bottom of the vertical furnace and is located below the filter screen plate.

[0017] Preferably, the combustion unit is connected to the dual-fuel switching supply unit, and the dual-fuel switching supply unit is signal-connected to the temperature control feedback unit.

[0018] The technical effects and advantages of this invention are as follows:

[0019] 1. The layered combustion design achieves gradient heating. The upper combustion unit preheats the raw materials, reducing the heat load on the lower combustion unit and increasing the overall melting speed. The dual swirl combustion technology increases the contact area between the flame and the raw materials, improves heat transfer efficiency, and shortens the time from raw material input to melting.

[0020] 2. The elastic buffer mechanism ensures a uniform and controllable descent speed of the raw materials, preventing localized accumulation and improving the space utilization of the vertical furnace. An inner sleeve is fixed to the inner wall of the furnace, with a frustum-shaped section inside. The base radius of the frustum is smaller than the top radius, allowing the descending recycled copper raw materials to descend in a centered position without colliding with the furnace wall. A finned tube heat exchanger recovers waste heat from the exhaust gas, increasing the secondary air temperature, reducing fuel consumption, and lowering production costs.

[0021] 3. The dual-band flame detector is linked with the ignition electrode. In case of flame abnormality, the fuel is cut off within seconds. Combined with the pressure alarm device, it achieves three levels of safety protection, eliminates the risk of explosion, and the independent waste discharge and copper discharge design reduces equipment blockage. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the combustion system structure of the vertical shaft furnace for direct rod making of recycled copper according to the present invention.

[0023] In the diagram: 1. Vertical furnace; 2. Conical inlet; 3. Box door; 4. Heat exchange pipe; 5. Staged air-heat circulation air supply unit; 6. Heat exchanger; 7. Rotating shaft; 8. Flexible baffle; 9. Inner sleeve; 10. Double swirl burner; 11. Filter plate; 12. Waste outlet; 13. Copper outlet; 14. Exhaust pipe. Detailed Implementation

[0024] This invention provides, for example Figure 1 The combustion system shown is for a vertical shaft furnace for direct rod making of recycled copper, including a vertical furnace 1 and a combustion unit, a staged hot air circulation supply unit 5 and a temperature control feedback unit. The combustion unit includes at least three double swirl burners 10, which are arranged around the furnace wall of the vertical furnace 1. Multiple sets of combustion units are arranged, and the multiple sets of combustion units are distributed along the height direction of the vertical furnace 1.

[0025] A feed inlet is provided on one side of the conical opening 2, and a box door 3 is provided on the feed inlet, through which recycled copper raw materials can be fed into the vertical furnace 1.

[0026] The upper combustion unit can preheat the descending recycled copper raw material, while the lower combustion unit can smelt the preheated recycled copper raw material, thereby increasing the smelting and combustion speed, improving efficiency, and reducing the combustion pressure on the bottom combustion unit.

[0027] The top of the vertical furnace 1 is provided with a conical opening 2, and the top of the conical opening 2 is connected to an exhaust pipe 14. A heat exchanger 6 is provided on the exhaust pipe 14. The heat exchanger 6 and the staged thermal circulation air supply system 5 are connected through a heat exchange pipe 4. The staged thermal circulation air supply system 5 is connected to a double swirl burner 10.

[0028] An inner sleeve 9 is fixed to the inner wall of the vertical furnace 1. The inner sleeve 9 has a frustum-shaped opening inside, with the base radius smaller than the top radius. This allows the descending recycled copper raw material to descend centrally without colliding with the inner wall of the furnace 1. The frustum-shaped inner sleeve 9 (base radius smaller than top radius), fixed to the inner wall of the furnace 1, works in conjunction with the internal buffer mechanism (rotating shaft 7 + elastic baffle 8) to guide the recycled copper raw material to descend smoothly along the central axis, avoiding localized wear from collisions with the furnace wall and reducing uneven heating caused by material accumulation. The design of the top conical opening 2 and the exhaust pipe 14 facilitates the centralized discharge of waste gas and enables waste heat recovery through the heat exchanger 6, forming an energy cycle.

[0029] The combustion port of the dual swirl burner 10 is inclined downward. The dual swirl burner 10 is equipped with a nested inner swirl channel and an outer swirl channel. The nested inner swirl channel (80-150mm) and the outer swirl channel (150-300mm) are combined with adjustable guide vanes (15°-45°) to precisely control the flame shape (length, diffusion angle) and adapt to the melting requirements of different height areas (such as upper preheating, middle melting, and lower heat preservation).

[0030] The staged heat circulation air supply unit 5 includes a primary air module, a secondary air module, and an air heat exchanger. The primary air module is connected to the inner vortex channel through an independent pipe, and the secondary air module, heat exchanger 6, and outer vortex channel are connected in sequence.

[0031] The temperature control feedback unit includes an infrared thermometer, a PLC controller, and an actuator. The infrared thermometer is installed at the top and bottom of the vertical furnace 1 to directly collect the temperature data inside the furnace. The infrared thermometer is connected to the PLC controller, the PLC controller is connected to the actuator, and the actuator is connected to the staged heat circulation air supply unit 5.

[0032] The infrared thermometer is positioned at two points, one above and one below, to collect temperatures in the 800-1300℃ range in real time. The data is transmitted to the PLC controller, which then dynamically adjusts the airflow and fuel supply via actuators. The dual-swirl burner features a built-in ignition electrode (8-15kV breakdown voltage) and a dual-band flame monitor (response time ≤0.5s), enabling rapid ignition and real-time flame status monitoring. In case of a malfunction, fuel is immediately cut off, enhancing operational safety.

[0033] The inner swirl channel of the dual swirl burner 10 has a diameter of 80-150mm, and the outer swirl channel has a diameter of 150-300mm. Adjustable guide vanes are provided at the outlets of both the inner and outer swirl channels, with an adjustment range of 15°-45°. Each dual swirl burner 10 has a built-in ignition electrode and a dual-band flame detector. The breakdown voltage of the ignition electrode is 8kV-15kV, and the response time of the flame detector is ≤0.5s.

[0034] The dual-band flame detector (response time ≤ 0.5s) is linked to the ignition electrode, and immediately cuts off the fuel when the flame is extinguished to eliminate the risk of explosion; the pressure alarm device monitors the fuel pressure (0.05-0.2MPa) in real time, and automatically shuts down when abnormal, reducing the incidence of safety accidents.

[0035] The primary air module of the staged air-heat circulation air supply unit 5 is equipped with a high-pressure centrifugal fan, with a primary air velocity of 15m / s-25m / s. The secondary air module is equipped with a variable frequency axial flow fan, with a secondary air velocity of 20m / s-35m / s. The heat exchanger 6 uses a finned tube type air-heat exchanger with a heat exchange efficiency of ≥85%, promoting complete fuel combustion. The air-heat exchanger is linked to the exhaust gas system of the vertical furnace 1 to achieve cascaded utilization of heat.

[0036] The inner sleeve 9 is equipped with multiple buffer mechanisms, including a rotating shaft 7 and an elastic baffle 8. The rotating shaft 7 is rotatably connected to the inner wall of the vertical furnace 1, and the elastic baffle 8 is fixed to the outside of the rotating shaft 7. The rotating shaft 7 is rotatably connected to the inner wall of the vertical furnace through a high-temperature bearing. The elastic baffle 8 is made of spring steel and has an arc-shaped structure, fixed to the outside of the rotating shaft. It can automatically adjust its angle (swing range 0-30°) according to the impact of the raw materials.

[0037] A filter plate 11 is installed at the bottom of the vertical furnace 1. A waste discharge port 12 is connected to one side of the vertical furnace 1, located above the filter plate 11. A copper discharge port 13 is connected to the bottom of the vertical furnace 1, located below the filter plate 11. The filter plate 11 separates molten copper from waste residue. The waste discharge port 12 and the copper discharge port 13 are designed independently to reduce equipment blockage and maintenance frequency. The filter plate 11 installed at the bottom of the furnace is made of 310S heat-resistant steel with a hole diameter of 8-12mm and is arranged at a 10° angle to facilitate the sliding of waste residue to the waste discharge port 12. The waste discharge port 12 is equipped with a water-cooled gate valve, which can achieve sealing and opening / closing at high temperatures.

[0038] The combustion unit is connected to the dual-fuel switching supply unit, and the dual-fuel switching supply unit and the temperature control feedback unit are connected by signals.

[0039] Example 1

[0040] Three sets of dual-swirl burners (inner channel φ100mm, outer channel φ200mm) are used, adapted for natural gas fuel. Staged air supply: primary air accounts for 20%, with a velocity of 15m / s; secondary air accounts for 80%, preheated to 150℃ by an air preheater, with a velocity of 20m / s. Guide vanes with a 15° angle are installed inside the primary and secondary air modules. The dual-swirl burners are connected to a dual-fuel switching supply unit, which controls the air-fuel ratio at 1:10 and the fuel pressure at 0.05MPa. The temperature control feedback unit is set at 1150℃, and the infrared thermometer has an accuracy of ±3℃. Exhaust gas purification: ammonia denitrification (injected at 850℃), with a denitrification efficiency of 80%; 5% sodium hydroxide desulfurization, with an efficiency of 90%. Operating results: combustion efficiency 95%, furnace temperature fluctuation ±5℃, NOx 150mg / m³. 3 SO2 50mg / m 3 The burner operated stably for 12 months.

[0041] Example 2

[0042] Four sets of dual-swirl burners (inner channel φ110mm, outer channel φ210mm) are used, adapted for natural gas fuel. Staged air supply: primary air accounts for 22%, with a velocity of 16m / s; secondary air accounts for 78%, preheated to 180℃, with a velocity of 22m / s and a guide vane angle of 18°. The dual-fuel switching supply unit controls the air-fuel ratio at 1:10.5 and the fuel pressure at 0.07MPa. The temperature control setting is 1180℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 8% ammonia water denitrification (injected at 860℃), efficiency 82%; 6% sodium hydroxide desulfurization, efficiency 91%. Operating results: combustion efficiency 95.5%, furnace temperature fluctuation ±4℃, NOx 145mg / m³. 3 SO2 45mg / m 3 The burner operated without fault for 13 months.

[0043] Example 3

[0044] Three sets of dual-swirl burners (inner channel φ90mm, outer channel φ190mm) are used, suitable for liquefied petroleum gas. Staged air supply: primary air accounts for 25%, with a velocity of 14m / s; secondary air accounts for 75%, preheated to 200℃, with a velocity of 20m / s and a guide vane angle of 20°. Air-fuel ratio is 1:11, fuel pressure is 0.08MPa. Temperature control is set at 1200℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 10% ammonia water denitrification (injected at 870℃), efficiency 83%; 7% sodium hydroxide desulfurization, efficiency 92%. Operating results: combustion efficiency 96%, furnace temperature fluctuation ±4℃, NOx 140mg / m³. 3 SO2 40mg / m 3 The burner has a lifespan of 14 months.

[0045] Example 4

[0046] Two sets of dual-swirl burners (inner channel φ120mm, outer channel φ220mm), adapted for natural gas. Staged air supply: primary air accounts for 28%, velocity 17m / s; secondary air accounts for 72%, preheated to 220℃, velocity 24m / s, guide vane angle 22°. Air-fuel ratio 1:11.5, fuel pressure 0.10MPa. Temperature control set at 1220℃, temperature measurement accuracy ±3℃. Exhaust gas purification: 7% ammonia denitrification (injected at 880℃), efficiency 84%; 7% sodium hydroxide desulfurization, efficiency 92%. Operating results: combustion efficiency 96%, furnace temperature fluctuation ±4℃, NOx 135mg / m³. 3 SO2 42mg / m 3 The burner operated stably for 13 months.

[0047] Example 5

[0048] Four sets of dual-swirl burners (inner channel φ100mm, outer channel φ200mm) are used, suitable for liquefied petroleum gas. Staged air supply: primary air accounts for 24%, with a velocity of 15m / s; secondary air accounts for 76%, preheated to 210℃, with a velocity of 21m / s and a guide vane angle of 20°. Air-fuel ratio is 1:11, fuel pressure is 0.09MPa. Temperature control is set at 1200℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 9% ammonia water denitrification (injected at 850℃), efficiency 83%; 6% sodium hydroxide desulfurization, efficiency 91%. Operating results: combustion efficiency 95.8%, furnace temperature fluctuation ±4℃, NOx 142mg / m³. 3 SO2 46mg / m 3 The burner operated without fault for 14 months.

[0049] Example 6

[0050] Three sets of dual-swirl burners (inner channel φ105mm, outer channel φ205mm) are used, adapted for natural gas. Staged air supply: primary air accounts for 23%, with a velocity of 15.5m / s; secondary air accounts for 77%, preheated to 200℃, with a velocity of 21m / s and a guide vane angle of 19°. Air-fuel ratio is 1:10.8, fuel pressure is 0.06MPa. Temperature control setting is 1190℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 8% ammonia water denitrification (injected at 865℃), efficiency 81%; 6% sodium hydroxide desulfurization, efficiency 90.5%. Operating results: combustion efficiency 95.2%, furnace temperature fluctuation ±4.5℃, NOx 148mg / m³. 3 SO2 48mg / m 3 The burner operated for 12.5 months.

[0051] Example 7

[0052] Four sets of dual-swirl burners (inner channel φ115mm, outer channel φ215mm) are used, suitable for liquefied petroleum gas. Staged air supply: primary air accounts for 26%, with a velocity of 16.5m / s; secondary air accounts for 74%, preheated to 250℃, with a velocity of 23m / s and a guide vane angle of 25°. Air-fuel ratio is 1:11.2, fuel pressure is 0.09MPa. Temperature control is set at 1210℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 9% ammonia water denitrification (injected at 880℃), efficiency 84%; 8% sodium hydroxide desulfurization, efficiency 92.5%. Operating results: combustion efficiency 96.2%, furnace temperature fluctuation ±3℃, NOx 138mg / m³. 3 SO2 38mg / m 3 The burner has a lifespan of 15 months.

[0053] Example 8

[0054] Three sets of dual-swirl burners (inner channel φ95mm, outer channel φ195mm) are used, adapted for natural gas. Staged air supply: primary air accounts for 21%, velocity 15m / s; secondary air accounts for 79%, preheated to 160℃, velocity 20m / s, guide vane angle 16°. Air-fuel ratio 1:10.2, fuel pressure 0.06MPa. Temperature control set at 1170℃, temperature measurement accuracy ±3℃. Exhaust gas purification: 6% ammonia water denitrification (injected at 855℃), efficiency 80%; 5.5% sodium hydroxide desulfurization, efficiency 90%. Operating results: combustion efficiency 95%, furnace temperature fluctuation ±5℃, NOx 149mg / m³. 3 SO2 50mg / m 3 The burner operated stably for 12 months.

[0055] Example 9

[0056] Two sets of dual-swirl burners (inner channel φ110mm, outer channel φ210mm) are used, suitable for liquefied petroleum gas. Staged air supply: primary air accounts for 30%, with a velocity of 18m / s; secondary air accounts for 70%, preheated to 280℃, with a velocity of 25m / s and a guide vane angle of 30°. Air-fuel ratio is 1:12, fuel pressure is 0.12MPa. Temperature control is set at 1250℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 10% ammonia water denitrification (injected at 890℃), efficiency 85%; 10% sodium hydroxide desulfurization, efficiency 93%. Operating results: combustion efficiency 96.5%, furnace temperature fluctuation ±3℃, NOx 130mg / m³. 3 SO2 35mg / m 3 The burner operated without failure for 16 months.

[0057] Example 10

[0058] Four sets of dual-swirl burners (inner channel φ100mm, outer channel φ200mm) are used, adapted for natural gas. Staged air supply: primary air accounts for 24%, velocity 16m / s; secondary air accounts for 76%, preheated to 230℃, velocity 22m / s, guide vane angle 22°. Air-fuel ratio 1:11, fuel pressure 0.08MPa. Temperature control set at 1200℃, temperature measurement accuracy ±3℃. Exhaust gas purification: 8% ammonia water denitrification (injected at 875℃), efficiency 83%; 7% sodium hydroxide desulfurization, efficiency 92%. Operating results: combustion efficiency 95.8%, furnace temperature fluctuation ±4℃, NOx 140mg / m³. 3 SO2 40mg / m 3 The burner operated for 14 months.

[0059] Example 11

[0060] Three sets of dual-swirl burners (inner channel φ108mm, outer channel φ208mm) are used, suitable for liquefied petroleum gas. Staged air supply: primary air accounts for 27%, with a velocity of 17m / s; secondary air accounts for 73%, preheated to 240℃, with a velocity of 23m / s and a guide vane angle of 24°. Air-fuel ratio 1:11.3, fuel pressure 0.10MPa. Temperature control setting 1220℃, temperature measurement accuracy ±3℃. Exhaust gas purification: 9% ammonia water denitrification (injected at 880℃), efficiency 84%; 8% sodium hydroxide desulfurization, efficiency 92.5%. Operating results: combustion efficiency 96.1%, furnace temperature fluctuation ±3.5℃, NOx 136mg / m³. 3 SO2 39mg / m 3 The burner has a lifespan of 15 months.

[0061] Example 12

[0062] Three sets of dual-swirl burners (inner channel φ102mm, outer channel φ202mm) are used, adapted for natural gas fuel. Staged air supply: primary air accounts for 22%, with a velocity of 15.5m / s; secondary air accounts for 78%, preheated to 200℃, with a velocity of 21m / s and a guide vane angle of 20°. An intelligent fuel supply system controls the air-fuel ratio at 1:10.6 and the fuel pressure at 0.07MPa. The temperature control feedback unit is set at 1190℃, and the infrared thermometer has an accuracy of ±3℃. Exhaust gas purification: 7% ammonia water denitrification (injected at 865℃), with a denitrification efficiency of 82%; 6.5% sodium hydroxide desulfurization, with an efficiency of 91.5%. Operating results: combustion efficiency 95.3%, furnace temperature fluctuation ±4℃, NOx 146mg / m³. 3 SO2 46mg / m 3 The burner operated continuously for 13 months without any faults.

[0063] Example 13

[0064] Four sets of dual-swirl burners (inner channel φ112mm, outer channel φ212mm) are used, suitable for liquefied petroleum gas. Staged air supply: primary air accounts for 25%, with a velocity of 16.5m / s; secondary air accounts for 75%, preheated to 260℃, with a velocity of 23m / s and a guide vane angle of 25°. A dual-fuel switching unit controls the air-fuel ratio at 1:11.2 and the fuel pressure at 0.09MPa. Temperature control is set at 1210℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 9% ammonia water denitrification (injected at 875℃), efficiency 83.5%; 8% sodium hydroxide desulfurization, efficiency 92.3%. Operating results: combustion efficiency 96%, furnace temperature fluctuation ±3.5℃, NOx 138mg / m³. 3 SO2 38mg / m 3 The burner operated stably for 14.5 months.

[0065] Example 14

[0066] Two sets of dual-swirl burners (inner channel φ115mm, outer channel φ215mm) are used, adapted for natural gas. Staged air supply: primary air accounts for 29%, with a velocity of 17.5m / s; secondary air accounts for 71%, preheated to 290℃, with a velocity of 24m / s and a guide vane angle of 28°. Air-fuel ratio is 1:11.8, fuel pressure is 0.13MPa. Temperature control is set at 1240℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 10% ammonia denitrification (injected at 890℃), efficiency 84.5%; 9% sodium hydroxide desulfurization, efficiency 92.8%. Operating results: combustion efficiency 96.4%, furnace temperature fluctuation ±3℃, NOx 132mg / m³. 3 SO2 36mg / m 3 The burner operated without failure for 15.5 months.

[0067] Example 15

[0068] Three sets of dual-swirl burners (inner channel φ95mm, outer channel φ195mm) are used, suitable for liquefied petroleum gas. Staged air supply: primary air accounts for 21%, with a velocity of 14.5m / s; secondary air accounts for 79%, preheated to 170℃, with a velocity of 20m / s and a guide vane angle of 17°. Air-fuel ratio 1:10.3, fuel pressure 0.06MPa. Temperature control setting 1170℃, temperature measurement accuracy ±3℃. Exhaust gas purification: 6% ammonia water denitrification (injected at 855℃), efficiency 81%; 5.5% sodium hydroxide desulfurization, efficiency 90.5%. Operating results: combustion efficiency 95.1%, furnace temperature fluctuation ±4.5℃, NOx 149mg / m³. 3 SO2 49mg / m 3 The burner operated for 12.5 months.

[0069] Example 16

[0070] Four sets of dual-swirl burners (inner channel φ105mm, outer channel φ205mm) are used, adapted for natural gas. Staged air supply: primary air accounts for 26%, with a velocity of 16m / s; secondary air accounts for 74%, preheated to 240℃, with a velocity of 22m / s and a guide vane angle of 23°. A dual-fuel switching unit controls the air-fuel ratio at 1:11.1 and the fuel pressure at 0.08MPa. Temperature control is set at 1200℃, with a temperature measurement accuracy of ±3℃. Exhaust gas purification: 8% ammonia water denitrification (injected at 870℃), efficiency 83%; 7% sodium hydroxide desulfurization, efficiency 92%. Operating results: combustion efficiency 95.8%, furnace temperature fluctuation ±4℃, NOx 142mg / m³. 3 SO2 42mg / m 3 The burner operated stably for 14 months.

Claims

1. A combustion system for a copper direct-to-bar shaft furnace, characterized in that, The vertical furnace (1) and the combustion unit, the staged heat cycle air supply unit (5) and the temperature control feedback unit, the combustion unit comprises at least three double swirl burners (10), three double swirl burners (10) are arranged around the furnace wall of the vertical furnace (1), and the combustion unit is arranged in multiple groups, and the multiple groups of combustion units are distributed along the height direction of the vertical furnace (1); The top end of the vertical furnace (1) is provided with a tapered port (2), the top end of the tapered port (2) is communicated with an exhaust pipe (14), the exhaust pipe (14) is provided with a heat exchanger (6), the heat exchanger (6) and the staged heat cycle air supply system (5) are connected through a heat exchange pipeline (4), and the staged heat cycle air supply system (5) is connected with the double swirl burner (10). The inner wall of the vertical furnace (1) is fixedly provided with an inner sleeve (9), and the inner sleeve (9) is internally provided with a frustum shape.

2. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: The combustion port of the double swirl burner (10) is inclined downward, and the double swirl burner (10) is provided with nested inner swirl channels and outer swirl channels.

3. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: The staged heat cycle air supply unit (5) comprises a primary air module, a secondary air module and a wind heat exchanger, the primary air module is connected to the inner swirl channel through an independent pipeline, and the secondary air module, the heat exchanger (6) and the outer swirl channel are sequentially connected.

4. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: The temperature control feedback unit comprises an infrared temperature measuring instrument, a PLC controller and an actuator, the infrared temperature measuring instrument is installed on the upper and lower parts of the vertical furnace (1) and directly collects the temperature data in the furnace, the infrared temperature measuring instrument and the PLC controller are signal connected, the PLC controller and the actuator are signal connected, and the actuator is connected with the staged heat cycle air supply unit (5).

5. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: The diameter of the inner swirl channel of the double swirl burner (10) is 80mm-150mm, the diameter of the outer swirl channel is 150mm-300mm, adjustable guide vanes are arranged at the outlets of the inner swirl channel and the outer swirl channel, the angle adjustment range of the vanes is 15°-45°, each double swirl burner (10) is internally provided with an ignition electrode and a double-waveband flame monitor, the breakdown voltage of the ignition electrode is 8kV-15kV, and the response time of the flame monitor is ≤0.5s.

6. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: The primary air module of the staged heat cycle air supply unit (5) is provided with a high-pressure centrifugal fan, the primary air speed is 15m / s-25m / s, the secondary air module is provided with a variable-frequency axial fan, the secondary air speed is 20m / s-35m / s, the heat exchanger (6) uses a finned tube type air heat exchanger, and the heat exchange efficiency is ≥85%.

7. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: The inner sleeve (9) is internally provided with a plurality of buffer mechanisms, the buffer mechanism comprises a rotating shaft (7) and an elastic baffle (8), the rotating shaft (7) is rotatably connected to the inner wall of the vertical furnace (1), and the elastic baffle (8) is fixed to the outer side of the rotating shaft (7).

8. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: A feeding port is formed in one side of the tapered port (2), and a box door (3) is arranged on the feeding port.

9. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: The vertical furnace (1) is internally provided with a filter screen plate (11) at the bottom end, one side of the vertical furnace (1) is communicated with a waste discharge port (12), the waste discharge port (12) is arranged above the filter screen plate (11), and the bottom end of the vertical furnace (1) is communicated with a copper discharge port (13), and the copper discharge port (13) is arranged below the filter screen plate (11).

10. A combustion system for a copper direct-to-bar shaft furnace for smelting according to claim 1, characterized in that: The combustion unit is connected with a dual-fuel switching supply unit, and the dual-fuel switching supply unit is signal connected with a temperature control feedback unit.

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