A corrosion-proof heat exchanger system for flue gas energy saving

Abstract

The utility model discloses a kind of anticorrosion heat exchanger systems for flue gas energy saving, including heat exchanger body, flue gas import passage, flue gas import passage, spray pipeline, spraying device, liquid collection bin, sedimentation tank, liquid storage pool, stirring device, dosing device, water pump.The utility model is periodically sprayed to the flue gas side of heat exchanger, and the spray water contains lye to neutralize the condensation acid in flue gas, to delay the service life of heat exchanger, reduce enterprise operating cost, guarantee the stable operation of flue gas energy saving treatment system, the recycling and automatic control of spray liquid, effectively improve the service life of heat exchanger, reduce operating cost, improve flue gas heat recovery efficiency and stability simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of flue gas treatment technology, specifically to a corrosion-resistant heat exchanger system for flue gas energy saving. Background Technology

[0002] In the field of modern industrial flue gas energy-saving treatment, heat exchangers, as core equipment for achieving efficient energy recovery and utilization and precise flue gas temperature control, are widely used in industries such as power, metallurgy, and chemicals. Statistics show that in coal-fired power plants, the energy utilization rate of the system can be increased by 8%-12% through waste heat recovery from flue gas via heat exchangers. However, industrial flue gas has a complex composition, typically containing acidic substances such as sulfur dioxide and sulfur trioxide at concentrations as high as 500-2000 mg / m³. When the flue gas temperature drops below the acid dew point (usually in the 120-160℃ range), these acidic substances rapidly condense to form highly corrosive condensate with a pH value below 2, initiating continuous chemical corrosion of the heat exchanger's metal materials.

[0003] Existing conventional metal heat exchangers (such as carbon steel and stainless steel) experience surface corrosion rates of 0.5-1.2 mm / year in acidic environments, resulting in an average equipment lifespan of only 2-3 years. Frequent corrosion problems such as perforation and leakage not only reduce energy recovery efficiency by 15%-25% but also force companies to invest heavily in equipment maintenance and replacement annually. Actual data from a steel company shows that annual maintenance costs due to heat exchanger corrosion reach as high as 3 million yuan, and each downtime for maintenance results in production losses exceeding 500,000 yuan, severely impacting the company's economic benefits and the continuous and stable operation of the system. Furthermore, corrosion products entering subsequent treatment stages can trigger a chain reaction of failures, such as blockages in desulfurization and denitrification equipment and catalyst poisoning, further exacerbating the difficulty of system operation and maintenance. Currently, overcoming the technical bottleneck of heat exchanger corrosion resistance has become a key issue restricting the efficient development of flue gas energy-saving treatment technology. Utility Model Content

[0004] Therefore, this utility model provides a corrosion-resistant heat exchanger system for flue gas energy saving to solve the above-mentioned problems in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] According to a first aspect of this utility model, a corrosion-resistant heat exchanger system for flue gas energy saving includes:

[0007] The heat exchanger body is made of metal and is used to absorb heat from flue gas to heat the medium required for heating.

[0008] A flue gas inlet channel and a flue gas outlet channel are provided on the flue gas side of the heat exchanger body;

[0009] A spray pipe is provided with several spray devices, which are used to atomize liquid and spray it onto the heat exchange surface of the heat exchanger body.

[0010] A liquid collection chamber is located at the bottom of the heat exchanger body and is connected to the heat exchanger body. The liquid collection chamber is used to collect spray liquid.

[0011] A settling tank, which is connected to a collection tank via a drain pipe, is used for solid-liquid separation of the spray liquid;

[0012] A liquid storage tank, which is connected to the upper part of the sedimentation tank via a pipe, is used to store the clear liquid after sedimentation;

[0013] A stirring device, wherein the blades of the stirring device are disposed within the liquid storage tank;

[0014] A dosing device is connected to the storage tank and is used to add alkaline solution to the storage tank.

[0015] A water pump, the inlet of which is connected to the liquid storage tank, and the outlet of which is connected to the spray pipe;

[0016] A liquid level sensor and a pH value detection device are installed in the liquid storage tank; and a control system is electrically connected to the liquid level sensor, the pH value detection device, the dosing device and the water pump respectively.

[0017] Furthermore, the spray pipe is disposed in at least one of the following locations:

[0018] Above the heat exchanger body;

[0019] The interior of the flue gas inlet channel;

[0020] The interior of the flue gas outlet channel;

[0021] The interior of the heat exchanger body.

[0022] Furthermore, the spraying device is an atomizing nozzle, which sprays the heat exchange surface of the heat exchanger body.

[0023] Furthermore, the bottom of the liquid collection chamber is a funnel structure, and the bottom of the funnel structure is connected to the bottom of the drain pipe.

[0024] Furthermore, the sedimentation tank is equipped with inclined plate or inclined tube sedimentation units.

[0025] Furthermore, the stirring device is located at the top of the liquid storage tank, and the impeller shaft of the stirring device is installed inside the liquid storage tank.

[0026] Furthermore, the heat exchanger body is a plate heat exchanger or a tubular heat exchanger.

[0027] This invention has the following advantages: It heats the medium by absorbing heat from the flue gas through the heat exchanger body. Combined with a circulation system consisting of spray pipes, a collection tank, a settling tank, and a storage tank, along with the coordinated operation of a level sensor, a pH detection device, and a control system, it achieves corrosion-resistant spray protection for the heat exchanger. By periodically spraying the flue gas side of the heat exchanger with alkaline water to neutralize the condensed acid in the flue gas, it extends the service life of the heat exchanger, reduces operating costs, and ensures the stable operation of the flue gas energy-saving treatment system. The recycling and automatic control of the spray solution effectively improves the service life of the heat exchanger, reduces operating costs, and enhances the efficiency and stability of flue gas heat recovery. Attached Figure Description

[0028] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0029] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0030] Figure 1 This is a schematic diagram of a corrosion-resistant heat exchanger system for flue gas energy saving, provided for some embodiments of this utility model.

[0031] Figure 2 This is a schematic diagram of a liquid storage tank for a corrosion-resistant heat exchanger system for flue gas energy saving, provided for some embodiments of the present invention.

[0032] Figure 3 This diagram illustrates the electrical connections of a level sensor, pH detection device, and control system for a corrosion-resistant heat exchanger system used for flue gas energy conservation, as provided in some embodiments of this utility model.

[0033] In the picture:

[0034] 1. Heat exchanger body; 2. Flue gas inlet channel; 3. Flue gas outlet channel; 4. Spray pipe; 5. Spray device; 6. Liquid collection tank; 7. Sedimentation tank; 8. Liquid storage tank; 801. Liquid level sensor; 802. pH value detection device; 803. Control system; 9. Stirring device; 10. Dosing device; 11. Water pump. Detailed Implementation

[0035] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0036] like Figures 1 to 3 As shown, a corrosion-resistant heat exchanger system for flue gas energy saving in the first aspect embodiment of this utility model includes a heat exchanger body 1, a flue gas inlet channel 2, a flue gas inlet channel 3, a spray pipe 4, a spray device 5, a liquid collection tank 6, a sedimentation tank 7, a liquid storage tank 8, a stirring device 9, a dosing device 10, and a water pump 11.

[0037] The heat exchanger body 1 is made of metal (such as carbon steel, stainless steel, etc.) and is used to absorb heat from flue gas to heat the medium required. The media on both sides of the heat exchanger body 1 do not come into contact. The heat exchanger body 1 can be in the form of a plate type or a tube type, etc.

[0038] A number of spray devices 5 are installed on the spray pipe 4. The spray devices 5 can convert the liquid into a mist, preferably an atomizing nozzle, and spray the spray water evenly onto the heat exchange surface of the heat exchanger.

[0039] The spray pipe 4 can be installed above the heat exchanger, or inside the flue gas inlet channel 2 or flue gas inlet channel 3, or inside the heat exchanger, in order to achieve full coverage of the heat exchange surface of the heat exchanger.

[0040] The heat exchanger body 1 has a liquid collection chamber 6 at its bottom. The bottom of the liquid collection chamber 6 is a funnel structure, which facilitates the rapid and smooth flow of the spray liquid into the drain pipe, reduces the residue of the spray liquid in the liquid collection chamber 6, improves the efficiency of liquid collection and discharge, and avoids the growth of impurities due to liquid residue affecting the operation of the system. The bottom of the funnel structure is connected to the bottom of the drain pipe, so that the spray water can be collected and transported to the settling tank 7 through the drain pipe. The settling tank 7 performs settling treatment on the spray water after spraying, and then the clear liquid at the top is transported to the storage tank 8 through the pipe. The storage tank 8 is equipped with a liquid level sensor 801, a pH value detection device 802 and a control system 803. The control system 803 is electrically connected to the liquid level sensor 801, the pH value detection device 802, the dosing device 10 and the water pump 11 respectively. The spray pipe 4 is positioned to cover the heat exchange surface of the heat exchanger body 1. The control system 803 controls water replenishment based on the signal from the liquid level sensor 801, starts the dosing device 10 to neutralize the acidity and alkalinity of the liquid based on the signal from the pH detection device 802, and starts the water pump 11 to perform spraying operations at set time intervals.

[0041] As an embodiment of this utility model, the control system 803 can be implemented using a PLC (such as the Mitsubishi FX series) or a microprocessor (such as the STM32F4 series), and its programming logic includes:

[0042] The pH sensor voltage signal is acquired by the ADC module and converted into a digital value.

[0043] If the pH value remains below the threshold for 5 minutes, start the dosing pump and start timing.

[0044] The opening degree of the water replenishment solenoid valve is controlled based on feedback from the liquid level sensor 801.

[0045]

[0046]

[0047] As an embodiment of the present invention, the stirring device 9 is disposed on the top of the liquid storage tank 8, and the blade shaft of the stirring device 9 is disposed inside the liquid storage tank 8. The stirring device 9 can fully mix the alkaline solution added by the dosing device 10 with the original liquid.

[0048] As an embodiment of this utility model, the sedimentation tank 7 is generally equipped with inclined plate or inclined tube sedimentation unit to improve the solid-liquid separation efficiency. This is prior art and will not be described in detail here.

[0049] When the heat exchanger system is running, the control system 803 periodically starts the water pump 11 at set time intervals to transport the liquid in the storage tank to the spray pipe 4. Through the spray device 5, the spray water containing alkaline solution is evenly sprayed onto the heat exchange surface of the heat exchanger metal body to completely neutralize the condensed acid produced by the cooling of flue gas and ensure the service life of the heat exchanger metal material.

[0050] This invention can achieve a comprehensive improvement in the energy-saving treatment efficiency of flue gas:

[0051] Significantly enhanced corrosion resistance: Based on real-time pH monitoring and the neutralization mechanism of alkali addition, the pH value of the condensed acid on the heat exchanger surface can be stably maintained within the safe range of 6-8, effectively inhibiting the corrosion rate and reducing the annual corrosion of the metal material from the conventional 0.5-1.2mm to below 0.08mm. The service life of the equipment is extended to 8-10 years, completely solving the problem of traditional heat exchangers needing to be replaced every 2-3 years.

[0052] Through the spray liquid recycling system, water resources can be reused at a rate exceeding 95%, and alkali consumption costs can be reduced by 40%. Extended equipment lifespan, coupled with intelligent operation and maintenance, reduces annual maintenance costs by over 70%, resulting in annual savings of over 2 million yuan per unit in comprehensive operating costs, significantly improving enterprise economic efficiency. Real-time dynamic neutralization eliminates the risk of energy leakage caused by corrosion perforation, ensuring that flue gas waste heat recovery efficiency remains consistently above 92%, a leading level in the industry. Simultaneously, it prevents chain reactions of malfunctions caused by corrosion products, such as blockages in desulfurization and denitrification equipment and catalyst poisoning, reducing unplanned system downtime by 85% and achieving continuous and stable operation 24 / 7. Avoiding the emission of corrosive pollutants, and combined with efficient heat exchange, it can increase energy utilization in industrial settings such as coal-fired power plants by 15%-20%, thereby achieving energy conservation and emission reduction.

[0053] Although the present invention has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

[0054] The terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation of this utility model. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of implementation of this utility model.

Claims

1. A corrosion-resistant heat exchanger system for flue gas energy saving, characterized in that, include: The heat exchanger body (1) is made of metal and is used to absorb the heat of flue gas to heat the medium required for heating. A flue gas inlet channel (2) and a flue gas outlet channel (3) are provided on the flue gas side of the heat exchanger body (1); Spray pipe (4), the spray pipe (4) is provided with several spray devices (5), the spray devices (5) are used to atomize the liquid and spray it onto the heat exchange surface of the heat exchanger body (1); Liquid collection chamber (6) is located at the bottom of the heat exchanger body (1) and is connected to the heat exchanger body (1). The liquid collection chamber (6) is used to collect spray liquid. A settling tank (7) is connected to a collection tank (6) via a drain pipe and is used for solid-liquid separation of the spray liquid. The liquid storage tank (8) is connected to the upper part of the sedimentation tank (7) through a pipe and is used to store the clear liquid after sedimentation. A stirring device (9) with blades disposed in the liquid storage tank (8); A dosing device (10) is connected to the storage tank (8) and is used to add alkaline solution to the storage tank (8); A water pump (11) is provided, with its inlet end connected to the liquid storage tank (8) and its outlet end connected to the spray pipe (4). A liquid level sensor (801) and a pH value detection device (802) are provided in the liquid storage tank (8); and a control system (803) is provided, which is electrically connected to the liquid level sensor (801), the pH value detection device (802), the dosing device (10) and the water pump (11).

2. The corrosion-resistant heat exchanger system for flue gas energy saving according to claim 1, characterized in that, The spray pipe (4) is located in at least one of the following positions: Above the heat exchanger body (1); The interior of the flue gas inlet channel (2); The interior of the flue gas outlet channel (3); The interior of the heat exchanger body (1).

3. The corrosion-resistant heat exchanger system for flue gas energy saving according to claim 1, characterized in that, The spraying device (5) is an atomizing nozzle, which sprays the heat exchange surface of the heat exchanger body (1).

4. A corrosion-resistant heat exchanger system for flue gas energy saving according to claim 1, characterized in that, The bottom of the liquid collection chamber (6) is a funnel structure, and the bottom of the funnel structure is connected to the bottom of the drain pipe.

5. A corrosion-resistant heat exchanger system for flue gas energy saving according to claim 1, characterized in that, The settling tank (7) is equipped with inclined plate or inclined tube settling units.

6. A corrosion-resistant heat exchanger system for flue gas energy saving according to claim 1, characterized in that, The stirring device (9) is located on the top of the liquid storage tank (8), and the blade shaft of the stirring device (9) is installed inside the liquid storage tank (8).

7. A corrosion-resistant heat exchanger system for flue gas energy saving according to claim 1, characterized in that, The heat exchanger body (1) is a plate heat exchanger or a tubular heat exchanger.

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