Energy-saving blast furnace gas fine desulfurization system

Abstract

This utility model provides an energy-saving blast furnace gas desulfurization system, comprising: a pretreatment tower (1), a dry desulfurization system (7), a water-based heat exchanger heating section (6) connected to the pretreatment tower (1), a hydrolysis tower (2) connected to the water-based heat exchanger heating section (6), a desulfurization tower (3) connected to the hydrolysis tower (2), and a water-based heat exchanger cooling section (5) connected to the dry desulfurization system (7); the water-based heat exchanger cooling section (5) is connected to the water-based heat exchanger heating section (6) by pipeline. It utilizes the waste heat resources in the hot blast stove flue gas, reducing the input of external energy and lowering overall energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of blast furnace gas desulfurization technology, specifically to an energy-saving blast furnace gas fine desulfurization system. Background Technology

[0002] With increasingly stringent environmental policies, the steel industry's demand for refined desulfurization of blast furnace gas is constantly increasing. Sulfides in blast furnace gas are mainly divided into inorganic sulfur and organic sulfur. Inorganic sulfur typically accounts for 25-35%, existing in the form of H2S; organic sulfur typically accounts for 65-80%, mainly existing in the forms of COS and CS2. In comparison, hydrogen sulfide can be removed through conventional chemical treatment, while organic sulfur, due to its stable molecular structure, is difficult to react with other substances, making it more challenging to treat. Therefore, the removal of organic sulfur has become the key to blast furnace gas desulfurization.

[0003] Currently, the main method for removing organic sulfur from blast furnace gas is hydrolysis. In this method, organic sulfur reacts with water to produce carbon dioxide and hydrogen sulfide under the action of a hydrolysis catalyst. The hydrolysis reaction temperature is typically between 60 and 90°C. Current fine desulfurization processes for blast furnace gas involve pretreatment before hydrolysis to remove chloride ions, fluoride ions, and other acid radicals from the gas. Organic sulfur is then converted to organic sulfur by the hydrolysis catalyst. After pretreatment, the temperature of the blast furnace gas is typically between 35 and 60°C, but the optimal temperature for the hydrolysis reaction is 60 to 90°C. Furthermore, the pretreated gas has a high moisture content; if it were directly introduced into the downstream system, it would produce a large amount of condensate, causing corrosion to downstream equipment. Therefore, the pretreated gas is usually heated. Existing processes often use steam heaters to heat the gas, requiring the introduction of steam from outside the blast furnace system. This not only leads to additional energy consumption but also increases the complexity of the system equipment and the difficulty of maintenance. Meanwhile, most blast furnace hot blast stoves in China use dry desulfurization for their flue gas. The temperature of the flue gas discharged after desulfurization is about 150°C. Directly discharging this high-temperature flue gas wastes valuable thermal energy resources.

[0004] In summary, the existing technology has the following problems: how to reduce energy consumption during the desulfurization process of blast furnace gas. Utility Model Content

[0005] This utility model provides an energy-saving blast furnace gas desulfurization system, which solves the technical problem of how to reduce energy consumption during the blast furnace gas desulfurization process.

[0006] To achieve the above objectives, this utility model proposes an energy-saving blast furnace gas desulfurization system, comprising:

[0007] The system comprises a pretreatment tower, a dry desulfurization system, a water-based heat exchanger heating section connected to the pretreatment tower, a hydrolysis tower connected to the water-based heat exchanger heating section, a desulfurization tower connected to the hydrolysis tower, and a water-based heat exchanger cooling section connected to the dry desulfurization system.

[0008] The cooling section of the water-based heat exchanger is connected to the heating section of the water-based heat exchanger via pipelines.

[0009] Specifically, it also includes: a chimney connected to the cooling section of the water-based heat exchanger.

[0010] Specifically, it also includes: a gas pressurization station connected to the desulfurization tower.

[0011] Specifically, it also includes: a circulating water pump installed on the pipeline connecting the cooling section and the heating section of the water-based heat exchanger.

[0012] Specifically, a water tank is provided between the cooling section and the heating section of the water-based heat exchanger.

[0013] Specifically, the circulating water pump is a variable frequency circulating water pump.

[0014] Specifically, it also includes a first temperature sensor and a second temperature sensor. The first temperature sensor is disposed on the heating section of the water-based heat exchanger, and the second temperature sensor is disposed on the cooling section of the water-based heat exchanger.

[0015] Specifically, it also includes a control system, which is connected to the circulating water pump.

[0016] The beneficial technical effects of the above-mentioned technical solution are as follows: This utility model realizes heat exchange between high-temperature hot blast stove flue gas and low-temperature blast furnace gas through a water-based heat exchanger, effectively raising the temperature of the blast furnace gas to the suitable temperature (60-90℃) required for the hydrolysis reaction, avoiding the energy consumption of additional steam heating in traditional processes. This technical solution utilizes the waste heat resources in the hot blast stove flue gas, reducing the input of external energy and lowering overall energy consumption. Moreover, by using the hot blast stove flue gas to raise the temperature of the blast furnace gas, the dependence on external steam and other energy sources is reduced, simplifying the energy supply mode of the system and reducing the complexity and maintenance difficulty of the equipment. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an energy-saving blast furnace gas desulfurization system according to an embodiment of the present invention.

[0018] Explanation of icon numbers:

[0019] 1. Pretreatment tower; 2. Hydrolysis tower; 3. Desulfurization tower; 4. Circulating water pump; 5. Cooling section of water-based heat exchanger; 6. Heating section of water-based heat exchanger; 7. Dry desulfurization system; 8. Chimney; 9. Gas pressurization station; 10. Water tank. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] This utility model embodiment provides an energy-saving blast furnace gas fine desulfurization system, such as Figure 1 As shown, the system includes: a pretreatment tower 1, a dry desulfurization system 7, a water-based heat exchanger heating section 6 connected to the pretreatment tower 1, a hydrolysis tower 2 connected to the water-based heat exchanger heating section 6, a desulfurization tower 3 connected to the hydrolysis tower 2, and a water-based heat exchanger cooling section 5 connected to the dry desulfurization system 7; the water-based heat exchanger cooling section 5 is connected to the water-based heat exchanger heating section 6 by pipeline. The water-based heat exchanger cooling section 5 is a finned tube water-based heat exchanger, and fins are provided on the outer side of the tube bundle of the water-based heat exchanger cooling section 5.

[0022] The shell side of the heating section 6 of the water-based heat exchanger is connected to the outlet of the pretreatment tower 1 via a pipeline to receive the pretreated low-temperature blast furnace gas, allowing the blast furnace gas to be heated by heat exchange with hot water before entering the hydrolysis tower. The shell side of the cooling section 5 of the water-based heat exchanger is connected to the outlet of the dry desulfurization system 7 of the hot blast stove flue gas via a pipeline to receive the high-temperature hot blast stove flue gas after dry desulfurization, allowing the hot blast stove flue gas to be cooled by heat exchange with cold water before entering the chimney 8 for exhaust. A water tank 10 is installed between the cooling section 5 and the heating section 6 of the water-based heat exchanger. The cooling section 5 and the heating section 6 are connected by pipelines. The water tank 10 contains a heat transfer medium, which is demineralized water. The water tank 10 can be connected to a demineralized water pipeline to obtain sufficient demineralized water. Hydrolysis tower 2 is filled with a hydrolysis catalyst, which is used to catalytically hydrolyze organic sulfur (COS, CS2) in coal gas into H2S and CO2. The catalyst has an activity temperature range of 60 to 90℃.

[0023] Blast furnace gas first enters pretreatment tower 1, where it undergoes water washing and spraying to remove chloride ions, fluoride ions, and other acid anions. After pretreatment, the gas temperature drops to 35–60°C, but not to the 60–90°C required for the hydrolysis reaction. The pretreated gas then enters the heating section 6 of a water-based heat exchanger, where it exchanges heat with the heat transfer medium. The water-based heat exchanger is matched to pretreatment tower 1, the dry desulfurization system 7, and its heat exchange capacity. A circulating water pump 4 is installed on the pipeline connecting the cooling section 5 and the heating section 6 of the water-based heat exchanger. The heat transfer medium, driven by the circulating water pump 4, carries the heat recovered from the hot blast stove flue gas, raising the gas temperature to 60–90°C to meet the process requirements of the subsequent hydrolysis tower. The circulating water pump 4 can be a variable frequency pump. A control system is connected to the circulating water pump 4 to adjust the circulating water flow rate based on real-time temperature data. The core function of the heating section of the water-based heat exchanger is to heat the pretreated, low-temperature blast furnace gas to the suitable temperature required for the hydrolysis reaction. Specifically, it heats the pretreated blast furnace gas (35–60°C) to 60–90°C, meeting the temperature requirements for the catalytic hydrolysis of organic sulfur compounds in the hydrolysis tower. Through the heat transfer medium, it recovers waste heat from the hot blast stove flue gas and transfers it to the blast furnace gas, replacing traditional steam heating and achieving energy-saving goals.

[0024] The flue gas from the dry desulfurization system 7, at a temperature of approximately 150°C, enters the cooling section 5 of the water-based heat exchanger. Under the action of a variable frequency circulating water pump, the demineralized water, acting as the heat transfer medium, flows sequentially through the cooling section 5 and the heating section 6 of the water-based heat exchanger, transferring the waste heat from the hot blast stove flue gas to the blast furnace gas. This effectively utilizes the waste heat resources of the hot blast stove flue gas, achieving energy savings. Inside the cooling section 5 of the water-based heat exchanger, the hot blast stove flue gas and circulating water undergo thorough heat exchange, reducing the flue gas temperature to approximately 90–110°C, while the circulating water temperature rises to 90–100°C after heat exchange.

[0025] Traditional processes use steam heaters to heat coal gas, requiring external steam input, resulting in high energy consumption and complex equipment. This invention utilizes the waste heat from the flue gas in the hot air furnace directly through a water-based heat exchanger heating section, eliminating the need for additional energy input. This simplifies the system while achieving energy savings, solving the technical problem of existing processes relying on external heat sources.

[0026] Example:

[0027] This utility model embodiment provides an energy-saving blast furnace gas desulfurization system, including a pretreatment tower 1, a hydrolysis tower 2, a desulfurization tower 3, a water-based heat exchanger group, and a circulating water pump 4 (variable frequency circulating water pump);

[0028] The water-based heat exchanger assembly includes a cooling section 5 and a heating section 6. These sections are connected to a circulating water pump 4 (a variable frequency circulating water pump) via pipelines, forming a closed-loop water circulation system. The pipelines contain demineralized water as the heat transfer medium. Based on the real-time system heat load (such as blast furnace gas flow rate and hot blast stove flue gas temperature fluctuations), the pump speed is adjusted via a variable frequency controller to precisely control the circulating water flow rate. The variable frequency controller can be linked with the water-based heat exchanger, temperature sensors, and other equipment to form an integrated energy-saving control system, reducing manual intervention and operational errors. This significantly improves the energy efficiency and stability of the blast furnace gas desulfurization system and achieves efficient waste heat recovery.

[0029] The heating section 6 of the water-based heat exchanger is connected to the pretreatment tower 1, the hydrolysis tower 2 is connected to the heating section 6 of the water-based heat exchanger, and the cooling section 5 of the water-based heat exchanger is connected to the dry desulfurization system 7.

[0030] The specific working process is as follows: the blast furnace gas is pretreated by a pretreatment tower; the waste heat in the hot blast stove flue gas is recovered by a water-based heat exchanger cooling section; the pretreated blast furnace gas is introduced into the heating section of a water-based heat exchanger for heat exchange with the circulating water in the water-based heat exchanger; and the heated blast furnace gas is introduced into a hydrolysis tower for organic sulfur hydrolysis treatment.

[0031] Specifically, the blast furnace gas first enters pretreatment tower 1, where it undergoes water washing and spraying to remove chloride ions, fluoride ions, and other acid ion impurities. After pretreatment, the gas temperature drops to 35–60°C. The pretreated gas is then transported via pipeline to the heating section 6 of a water-based heat exchanger. Simultaneously, the hot blast stove flue gas, at approximately 150°C, exits from the dry desulfurization system and enters the cooling section 5 of the water-based heat exchanger.

[0032] Under the action of the variable frequency circulating water pump 4, the demineralized water medium flows sequentially through the cooling section 5 and the heating section 6 of the water-based heat exchanger, transferring the waste heat of the hot blast stove flue gas to the blast furnace gas, thereby effectively utilizing the waste heat resources of the hot blast stove flue gas and achieving energy-saving effects. Inside the cooling section 5 of the water-based heat exchanger, the hot blast stove flue gas and the circulating water undergo sufficient heat exchange, reducing the temperature of the hot blast stove flue gas to about 90-110℃, while the temperature of the circulating water rises to 90-100℃ after heat exchange.

[0033] Inside the heating section 6 of the water-based heat exchanger, the blast furnace gas and circulating water undergo thorough heat exchange, raising the gas temperature to 60–90°C, which meets the process temperature requirements of the hydrolysis tower. Simultaneously, the circulating water temperature drops to approximately 80°C after heat exchange. The blast furnace gas exiting the heating section 6 enters the hydrolysis tower 2, where a hydrolysis catalytic reaction converts the organic sulfur in the gas into inorganic sulfides. This process, completed under the action of the hydrolysis catalyst, significantly reduces the organic sulfur content, facilitating subsequent desulfurization treatment.

[0034] The hydrolyzed blast furnace gas enters desulfurization tower 3, where H2S is removed through desulfurization processes such as alkaline washing, ensuring that the sulfur content in the gas meets emission standards. After desulfurization, the gas is transported to the user end via gas pressurization station 9.

[0035] The cooled blast furnace flue gas exiting the cooling section 5 of the water-based heat exchanger is then discharged into the chimney. This emission process complies with environmental standards, avoids the direct emission of high-temperature flue gas and the waste of heat energy, and significantly reduces the external energy consumption of the blast furnace gas desulfurization system.

[0036] This invention offers significant energy savings: by utilizing a water-based heat exchanger to achieve heat exchange between high-temperature hot blast stove flue gas and low-temperature blast furnace gas, the temperature of the blast furnace gas is effectively raised to the suitable temperature (60-90℃) required for the hydrolysis reaction, avoiding the energy consumption of additional steam heating in traditional processes. This technical solution utilizes the waste heat resources in the hot blast stove flue gas, reducing the input of external energy and lowering overall energy consumption.

[0037] This utility model simplifies the equipment and process: by using the flue gas from the hot blast stove to heat the blast furnace gas, it reduces the dependence on external energy sources such as steam, simplifies the energy supply mode of the system, and reduces the complexity and maintenance difficulty of the equipment.

[0038] The above description is merely an illustrative embodiment of this utility model and is not intended to limit the scope of this utility model. The various components of this utility model can be combined with each other without conflict. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of this utility model should fall within the protection scope of this utility model.

Claims

1. An energy-saving blast furnace gas desulfurization system, characterized in that, include: The pretreatment tower (1), the dry desulfurization system (7), the water-based heat exchanger heating section (6) connected to the pretreatment tower (1), the hydrolysis tower (2) connected to the water-based heat exchanger heating section (6), the desulfurization tower (3) connected to the hydrolysis tower (2), and the water-based heat exchanger cooling section (5) connected to the dry desulfurization system (7); The cooling section (5) of the water-based heat exchanger is connected to the heating section (6) of the water-based heat exchanger via pipeline.

2. The energy-saving blast furnace gas desulfurization system according to claim 1, characterized in that, Also includes: Chimney (8) connected to the cooling section (5) of the water-based heat exchanger.

3. The energy-saving blast furnace gas desulfurization system according to claim 1, characterized in that, Also includes: A gas pressurization station (9) connected to the desulfurization tower (3).

4. The energy-saving blast furnace gas desulfurization system according to claim 1, characterized in that, Also includes: A circulating water pump (4) is installed on the pipeline connecting the cooling section (5) and the heating section (6) of the water-based heat exchanger.

5. The energy-saving blast furnace gas desulfurization system according to claim 1, characterized in that, A water tank (10) is provided between the cooling section (5) and the heating section (6) of the water-based heat exchanger.

6. The energy-saving blast furnace gas desulfurization system according to claim 4, characterized in that, The circulating water pump (4) is a variable frequency circulating water pump.

7. The energy-saving blast furnace gas desulfurization system according to claim 1, characterized in that, It also includes a first temperature sensor and a second temperature sensor. The first temperature sensor is disposed on the heating section (6) of the water-based heat exchanger; the second temperature sensor is disposed on the cooling section (5) of the water-based heat exchanger.

8. The energy-saving blast furnace gas desulfurization system according to claim 4, characterized in that, It also includes a control system, which is connected to the circulating water pump (4).

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