A heat exchange system suitable for low-sulfur high-temperature flue gas generated in a copper smelting process

Abstract

The utility model discloses a kind of heat exchange systems suitable for low-sulfur high-temperature flue gas generated in copper smelting process, flue heat exchange device and water-cooling heat exchange device are combined, by different temperature flue gas generated in different process stages is graded regulation and control, realize that flue gas temperature smoothly transitions, while maximum limit recovery waste heat under the condition of satisfying into dust collection system, flue gas is initially reduced temperature to 350~600 DEG C by flue heat exchange device, then according to flue gas temperature sensor real-time detection after flue heat exchange device preliminary cooling flue gas temperature, utilize DCS regulation and control unit control water-cooling heat exchange device's heat exchange intensity (the flow of heat exchange medium), make after heat exchange export flue gas temperature drop to 150~210 DEG C, avoid flue gas temperature too low and approach dew point, satisfy the condition that flue gas enters dust collection system.

Description

Technical Field

[0001] This utility model belongs to the field of copper smelting flue gas treatment technology, and in particular relates to a heat exchange system suitable for low-sulfur high-temperature flue gas generated during copper smelting. Background Technology

[0002] The processing technology for smelting crude copper both domestically and internationally primarily employs pyrometallurgical refining, mainly involving oxidation and reduction processes. Pyrometallurgical refining uses smelted crude copper as raw material and employs an anode furnace for pyrometallurgical refining. It mainly includes five process stages: feed holding, pre-oxidation, oxidation, reduction, and casting. Auxiliary materials such as coke, quartz, and sodium carbonate are added during the refining process. Currently, the flue gas generated during refining is mainly treated by water cooling in flues and hoods before entering the dust collection and desulfurization system. However, this method has a simple heat exchange structure and fails to differentiate the temperature characteristics of the flue gas according to different process stages. In particular, for high-temperature flue gas in some process stages, heat exchange makes it easier for the flue gas to reach its dew point temperature, significantly impacting the entire pyrometallurgical refining dust collection system. This problem is prevalent in various pyrometallurgical refining production lines in China, and there is currently no effective solution. Utility Model Content

[0003] (1) Technical problem to be solved: Traditional single water cooling heat exchange cannot be differentiated according to the temperature characteristics of flue gas in different process stages, which makes it easier for the flue gas to reach the dew point temperature after heat exchange in some process stages. This utility model provides a heat exchange system suitable for low sulfur high temperature flue gas generated in the copper smelting process.

[0004] (2) The technical solution adopted by this utility model is as follows: A heat exchange system suitable for low-sulfur, high-temperature flue gas generated during copper smelting includes a DCS control unit and a flue gas heat exchange device, a flue gas temperature sensor, and a water-cooled heat exchange device connected sequentially to the flue. The flue gas heat exchange device is installed on the outer wall of the flue and is used to initially cool the flue gas through radiative heat exchange. The flue gas temperature sensor is installed on the flue to detect the flue gas temperature. The water-cooled heat exchange device has a flue gas inlet, a flue gas outlet, and a water inlet flow valve. The flue gas inlet is connected to the flue, and a flue gas control valve is installed at the connection between the flue gas inlet and the flue. The flue gas outlet is connected to a cold flue gas channel. A bypass pipe is connected between the flue and the cold flue gas channel, and a bypass valve is installed on the bypass pipe. The flue gas temperature sensor is connected to the DCS control unit, and the DCS control unit is connected to the water inlet flow valve and the bypass valve.

[0005] A further technical solution is that the flue heat exchange device includes two arc-shaped water jackets, which sandwich and wrap around the flue. Baffles are provided inside the arc-shaped water jackets, and water inlet and water outlet are provided on the arc-shaped water jackets.

[0006] A further technical solution involves installing outlet control valves at the flue gas outlet and the cold flue gas passage.

[0007] (3) Due to the adoption of the above technical solution, the beneficial effects of this utility model are: 1. By combining flue gas heat exchangers with water-cooled heat exchangers, the flue gas at different temperatures generated at different process stages is graded and regulated to achieve a stable transition in flue gas temperature, thereby maximizing the recovery of waste heat while meeting the conditions for entering the dust collection system.

[0008] 2. The flue gas first passes through a flue heat exchanger to initially reduce its temperature to 350-600℃. Then, based on the real-time monitoring of the flue gas temperature after the initial cooling by the flue heat exchanger using a flue gas temperature sensor, the heat exchange intensity (flow rate of the heat exchange medium) of the water-cooled heat exchanger is controlled by the DCS control unit to reduce the outlet flue gas temperature to 150-210℃, thus preventing the flue gas temperature from becoming too low and approaching the dew point, and meeting the conditions for the flue gas to enter the dust collection system.

[0009] 3. If the flue gas temperature sensor detects in real time that the flue gas temperature after preliminary cooling by the flue heat exchange device is <250℃, the DCS control unit controls the bypass valve to open and simultaneously controls the flue gas control valve to close, so that the flue gas can be directly connected to the cold flue gas channel from the bypass pipe, thus preventing the flue gas from reaching the dew point temperature. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the arc-shaped water jacket installation structure of the flue heat exchange device described in this utility model; Figure 3 This is a schematic diagram of the internal unfolded structure of the arc-shaped water jacket described in this utility model; Figure 4 This is a schematic diagram showing the positions of the water inlet and water outlet of the arc-shaped water jacket described in this utility model; Figure 5 This is a block diagram of the control logic of the DCS control unit described in this utility model; Figure 6 This is a schematic diagram of the structure of the water-cooled heat exchange device described in this utility model. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0012] like Figures 1-6 As shown.

[0013] Example 1: A heat exchange system suitable for low-sulfur, high-temperature flue gas generated during copper smelting includes a DCS control unit and a flue gas heat exchange device 2, a flue gas temperature sensor 3, and a water-cooled heat exchange device 4 connected sequentially to a flue duct 1. The flue gas heat exchange device 2 is installed on the outer wall of the flue duct 1 and is used to initially cool the flue gas through radiative heat exchange. The flue gas temperature sensor 3 is installed on the flue duct 1 to detect the flue gas temperature. The water-cooled heat exchange device 4 has a flue gas inlet 5, a flue gas outlet 6, and a water inlet flow valve 7. The flue gas inlet 5 is connected to the flue duct 1, and a flue gas control valve 8 is installed at the connection between the flue gas inlet 5 and the flue duct 1. The flue gas outlet 6 is connected to a cold flue gas channel 9. A bypass pipe 10 is connected between the flue duct 1 and the cold flue gas channel 9. A bypass valve 11 is installed on the bypass pipe 10. The flue gas temperature sensor 3 is connected to the DCS control unit, and the DCS control unit is connected to the water inlet flow valve 7, the bypass valve 11, and the flue gas control valve 8. The flue heat exchanger 2 is a radiant heat exchanger, and the water-cooled heat exchanger 4 is a tubular heat exchanger. The water-cooled heat exchanger 4 adopts an upper inlet and upper outlet configuration. Several convective heat exchange tube bundles are installed inside the water-cooled heat exchanger 4. Flue gas enters from the upper part of one side of the water-cooled heat exchanger 4, undergoes vertical convective heat exchange with the convective heat exchange tube bundles, and then enters the cold flue gas channel 9 from the upper part of the other side of the water-cooled heat exchanger 4. The water-cooled heat exchanger 4 is connected to the dust collection device through the cold flue gas channel 9. After heat exchange, the flue gas enters the dust collection device. The flue heat exchanger 2 can be a traditional heat exchange device mounted on the flue, and the water-cooled heat exchanger 4 can be a traditional tubular heat exchanger. This tubular heat exchanger has a flue gas inlet 5, a flue gas outlet 6, a cooling water inlet, and a cooling water outlet. The cooling water inlet is connected to an inlet pipe, and an inlet pipe flow valve 7 is installed on the inlet pipe. The water-cooled heat exchanger 3, manufactured by Nanjing Huadian Energy Conservation and Environmental Protection Co., Ltd., contains three sets of water tanks, each equipped with 12 rows of serpentine coils for flue gas heat exchange. This ensures the inlet water temperature of the water-cooled heat exchanger remains stable at approximately 40°C, preventing internal ash caking due to excessively cold flue gas. Flue gas guide plates are installed at the inlet and outlet of the water-cooled heat exchanger to ensure effective contact between the flue gas and the serpentine coils, improving waste heat utilization. Simultaneously, control valves are installed at the flue gas inlet 5, flue gas outlet 6, and bypass flue duct 10, adjusting and controlling the high-temperature flue gas based on the flue gas temperature sensor 3.

[0014] Working process: The flue gas is cooled by radiative heat exchange through the flue heat exchange device 2, which can reduce the flue gas temperature by 50-80℃. A flue gas temperature sensor 3 is installed on flue 1, and real-time flue gas temperature data is fed back from the sensor. Through DCS program settings, the temperature feedback data is associated with the oxidation-reduction system process operation mode within the DCS to determine the current process stage (feeding and insulation, oxidation, reduction) and temperature range. The water cooling heat exchange intensity can be dynamically adjusted using the DCS control unit (DCS control system). The water cooling heat exchange flow rate is adjusted by a percentage, and a bypass valve is triggered when the flue gas temperature is <250℃. When valve 11 is opened, flue gas control valve 8 is closed, and the flue gas bypass is opened, preventing flue gas from entering the water-cooled heat exchanger 4. An interlock is set every 50°C from 250°C to 700°C, linked to the inlet flow valve 7 of the water inlet pipe of the water-cooled heat exchanger 4, with an adjustment range of 2%. The water cooling intensity adjustment range is 5-20% during the feeding and insulation stages, 20-80% during the oxidation stage, and 50-100% during the reduction stage. After gradient heat exchange through the flue heat exchanger 2 and the water-cooled heat exchanger 4, the flue gas reaches the temperature range required by the dust collection device and finally enters the subsequent dust collection device. This operation method allows for stepped heat exchange control of flue gas at different temperatures in different process stages, effectively solving problems such as flue gas condensation, corrosion, and decreased dust collection efficiency caused by the single heat exchange method in existing technologies. It significantly improves the efficiency of flue gas waste heat recovery and ensures the environmentally friendly and stable operation of the pyrometallurgical refining production line.

[0015] Example 2: The flue gas heat exchange device 2 consists of two arc-shaped water jackets, which sandwich and wrap around the flue. Baffles are installed inside the arc-shaped water jackets, and water inlets and outlets are provided on the arc-shaped water jackets. The circulating water path of each water jacket is independent, and a regulating valve is installed at the inlet to regulate and control the low-temperature flue gas based on the feedback data from the flue gas temperature sensor 3.

[0016] Example 3: By adjusting the cooling water flow rate in real time according to the flue gas temperature, the loop in the water-cooled heat exchanger 2 leading to the circulating water pool can ensure that the inlet water temperature of the water-cooled heat exchanger 2 is stable at around 40℃, reducing the phenomenon of soot caking inside the water-cooled heat exchanger 2. At the same time, the control valves installed at the flue gas inlet 5 and the flue gas outlet 6 can be used to regulate the negative pressure of the flue gas, which is beneficial to the production control and operation of the anode furnace.

Claims

1. A heat exchange system suitable for low-sulfur, high-temperature flue gas generated during copper smelting, characterized in that, The system includes a DCS control unit and a flue heat exchange device (2), a flue gas temperature sensor (3), and a water-cooled heat exchange device (4) connected in sequence to the flue (1). The flue heat exchange device (2) is installed on the outer wall of the flue (1) and is used to initially cool the flue gas through radiative heat exchange. The flue gas temperature sensor (3) is installed on the flue (1) to detect the flue gas temperature. The water-cooled heat exchange device (4) has a flue gas inlet (5), a flue gas outlet (6), and a water inlet flow valve (7). The flue gas inlet (5) is connected to the flue (1), and a flue gas control valve (8) is provided at the connection between the flue gas inlet (5) and the flue (1). The flue gas outlet (6) is connected to the cold flue gas channel (9). A bypass flue (10) is connected between the flue (1) and the cold flue gas channel (9). A bypass valve (11) is provided on the bypass flue (10). The flue gas temperature sensor (3) is connected to the DCS control unit. The DCS control unit is connected to the inlet water pipe flow valve (7), the bypass valve (11), and the flue gas control valve (8).

2. The heat exchange system for low-sulfur, high-temperature flue gas generated during copper smelting, as described in claim 1, is characterized in that... The flue heat exchange device (2) includes two arc-shaped water jackets (13), which sandwich the flue (1). A baffle plate (12) is provided inside the arc-shaped water jacket (13), and a water inlet (14) and a water outlet (15) are provided on the arc-shaped water jacket (13).

3. A heat exchange system for low-sulfur, high-temperature flue gas generated during copper smelting, as described in claim 1, is characterized in that, An outlet control valve (16) is installed at the flue gas outlet (6) and the cold flue gas passage (9).

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