Steam condensate optimized utilization device for heat storage station of steel mill

Abstract

The utility model discloses a steam condensate optimized utilization device for a heat storage station of a steel plant, and belongs to the technical field of steam recycling of an evaporative cooling system of the steel plant. The device comprises a sampling device, a heat accumulator, a heat exchanger, a recycling water tank and a connecting pipeline of the recycling water tank and a softened water tank, sampling devices are respectively arranged on the heat accumulator and the recovery water tank, and each sampling device comprises a sampling pipe and a sampling valve and is used for testing the water quality of the steam condensate water; a connecting pipeline of the recovery water tank and the softened water tank is a recovery and control pipeline arranged between the heat storage station recovery water tank and the converter softened water tank, and steam condensate water is conveyed to the converter softened water tank to be recycled; a pneumatic valve is additionally arranged on a connecting pipeline of the recycling water tank and the soft water tank, and the purpose that the converter soft water tank preferentially uses recycled steam condensate water is achieved by controlling opening and closing of the valve. The heat exchanger is a welded plate type heat exchanger. The steam condensate water recycling device solves the problem that steam condensate water of a steel plant is discharged and wasted, and resource recycling and gradient utilization are achieved.

Description

Technical Field

[0001] This utility model relates to a device for optimizing the utilization of steam condensate in a steel plant's thermal storage station, belonging to the technical field of steam recovery and utilization in steel plant vaporization cooling systems. Background Technology

[0002] During the converter and AOD steelmaking processes in steel plants, a large amount of high-temperature flue gas is generated. The main function of the vaporization cooling device is to reduce the flue gas temperature, recover waste heat from the high-temperature flue gas, and create conditions for flue gas dust removal and coal gas recovery. The steam generated by the vaporization cooling system during converter and AOD steelmaking is sent to the heat storage station through pipelines. After being collected, distributed, and classified by the heat storage device, it is sent to the company's pipeline network for winter heating and unit power generation. The condensate generated during the process is cooled by heat exchangers and then enters the recovery water tank, serving as fresh industrial water for the evaporative cooling water tank.

[0003] With the increase in the number of converters and AOD furnaces, and the application of new processes such as dephosphorization, desulfurization, and desiliconization smelting, and high-silicon pre-melted liquid smelting, the consumption of demineralized water by the vaporization cooling system has increased significantly, leading to a substantial increase in water costs. Furthermore, the amount of condensate generated during steam utilization has also increased, far exceeding the consumption of the converter evaporation cooling system. Except for a small portion used as fresh industrial water for the evaporation cooling water tank, the majority is directly discharged through the overflow pipe, resulting in significant resource waste. Simultaneously, due to the increased condensate volume, the heat exchanger's heat exchange capacity cannot meet the new heat exchange requirements, leading to a decrease in condensate cooling efficiency and posing an environmental pollution risk due to its discharge. Utility Model Content

[0004] To overcome the above shortcomings, this utility model provides a device for optimizing the utilization of steam condensate in a steel plant's heat storage station. This device breaks through the traditional methods of utilizing and disposing of steam condensate, prioritizing its supply to the converter soft water tank, and using the surplus to replenish the evaporative cooling water tank, thus realizing the recovery and efficient utilization of steam condensate.

[0005] This invention first conducts water quality testing on the steam condensate. The analysis confirms that the steam condensate from the thermal storage station is of good quality and can completely replace demineralized water in the vaporization cooling system. Considering that directly discharging this condensate results in significant resource waste, and using it as fresh industrial water in the evaporative cooling system does not fully utilize its water quality advantages, this invention proposes prioritizing the use of the wasteful and inefficiently utilized steam condensate from the thermal storage station in the vaporization cooling system.

[0006] The technical solution adopted by this utility model is: a device for optimizing the utilization of steam condensate in a steel plant heat storage station, including a sampling device, a heat storage unit, a heat exchanger, a recovery water tank, and a pipeline connecting the recovery water tank and the soft water tank;

[0007] Sampling devices are installed on the heat accumulator and the recovery water tank. The sampling devices include sampling tubes and sampling valves, which are used to test the water quality of steam condensate. Water samples are collected regularly for testing and analysis to detect and eliminate abnormalities in a timely manner and ensure water quality stability.

[0008] The connection pipeline between the recovery water tank and the soft water tank is as follows: a recovery and control pipeline is set between the recovery water tank of the thermal storage station and the soft water tank of the converter to send the steam condensate to the soft water tank of the converter for recycling; a pneumatic valve is added on the basis of the increased pipeline, and the purpose of prioritizing the use of the recovered steam condensate in the soft water tank is achieved by controlling the opening and closing of the valve (adjusting parameters and adding interlocks).

[0009] An additional heat exchanger, a welded plate heat exchanger, was added, increasing the heat exchange area and operating pressure. This upgrade and modification of the existing heat exchanger ensures that the condensate temperature meets the requirements of the vaporization cooling system.

[0010] An interlock is installed on the water tank to start and stop the water pump. The water pump starts to collect water when the water level in the tank reaches the high level and stops when the water level is lower than the low level. The water pump is allowed to start when the water temperature in the tank is lower than the alarm value, but is not allowed to start when the water temperature is higher than the alarm value.

[0011] Furthermore, a branch pipeline is installed between the heat storage station's recovery water tank and the evaporative cooling soft water tank, and a pneumatic valve is installed on the main branch pipeline to enable the pipeline to switch between the evaporative cooling soft water tank and the converter soft water tank; a pneumatic valve is installed on the pipeline at the top of the soft water tank.

[0012] Furthermore, an interlock is added between the opening and closing of the pneumatic valve on top of the converter soft water tank and the water level in the converter soft water tank. This is set in the pneumatic valve control program so that the interlocked water level range is higher than the company's automatic water replenishment range. For example, the automatic water replenishment level of the demineralized water in the pipeline is adjusted from 2000mm to 1500mm (automatic water replenishment below 1500mm), and the pneumatic valve is set to open to replenish water to the tank when the water level in the converter soft water tank is lower than the high water level (3500mm), and to close to stop replenishing water to the tank when the water level reaches the high high water level (3950mm).

[0013] Furthermore, the heat exchanger was changed from a rubber-sealable plate heat exchanger to a welded plate heat exchanger, and the heat exchange area was increased from 198m². 2 Increased to 310m 2 The maximum pressure increased from 1.6 MPa to 2.0 MPa.

[0014] The beneficial effects of the optimized utilization device for steam condensate in steel plant thermal storage stations provided by this utility model are as follows:

[0015] (1) It solved the problem of waste in the discharge of steam condensate from steel plants and realized the recycling and cascade utilization of resources;

[0016] (2) Steam condensate is used to replace demineralized water and is given priority to supply the converter soft water tank, thereby reducing the consumption of demineralized water in the vaporization cooling system. When there is surplus, water can be added to the evaporative cooling water tank to reduce the consumption of industrial fresh water.

[0017] (3) The converter soft water tank should be replenished with steam condensate first. If the steam condensate is insufficient, the demineralized water from the company's pipeline should be used for replenishment. The evaporative cold water tank should be replenished with industrial fresh water from the company's pipeline first. If the industrial fresh water is insufficient (due to a water supply system failure) or if the steam condensate is abundant, steam condensate should be used for replenishment.

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] In the diagram: 1 is the steam drum, 2 is the soft water tank, 3 is the heat accumulator, 4 is the heat exchanger, 5 is the recovery water tank, 6 is the user, 7 is the evaporative cold soft water tank, 8 is the connecting pipeline between the recovery water tank and the soft water tank, 9 is the sampling device, 10 is the pneumatic valve, and 11 is the branch pipeline; A is steam condensate, B is makeup water after deoxygenation, C is steam generated by water circulating and absorbing heat in the vaporization flue, D is condensate, E is water after heat exchange, F is steam supplied to users, G is emergency makeup water, and H is steam condensate makeup water. Detailed Implementation

[0021] Example

[0022] like Figure 1 As shown, a device for optimizing the utilization of steam condensate in a steel plant heat storage station includes: a sampling device 9, a heat storage unit 3, a heat exchanger 4, a recovery water tank 5, and a connecting pipeline 8 between the recovery water tank and the soft water tank.

[0023] Sampling devices 9 are installed on the heat storage tank 3 and the recovery water tank 5 respectively. The sampling devices 9 include sampling tubes and sampling valves, which are used to test the water quality of steam condensate. Water samples are collected regularly for testing and analysis to detect and eliminate abnormalities in a timely manner and ensure water quality stability.

[0024] The connection pipeline 8 between the recovery water tank and the soft water tank is: a recovery and control pipeline set between the recovery water tank 5 of the thermal storage station and the soft water tank 2 of the converter, which sends the steam condensate A to the soft water tank 2 of the converter for recovery and reuse; on the basis of adding pipeline, a pneumatic valve 10 is added, and by controlling the opening and closing of the valve (adjusting parameters and adding interlocks), the purpose of giving priority to the use of the recovered steam condensate (replacing demineralized water) in the soft water tank of the converter is achieved;

[0025] Add a heat exchanger 4, which is a welded plate heat exchanger, to increase the heat exchange area and operating pressure. This upgrades the existing heat exchanger so that the condensate temperature meets the requirements of the vaporization cooling system.

[0026] An interlock is set on the recovery water tank 5 to start and stop the water pump. When the water level in the recovery water tank reaches the high level, the water pump starts to recover water, and when the water level is lower than the low level, the water pump stops. The water pump is allowed to start when the water temperature in the tank is lower than the alarm value, and is not allowed to start when the water temperature is higher than the alarm value.

[0027] Furthermore, a branch pipeline 11 is installed between the heat storage station recovery water tank 5 and the evaporative cold soft water tank 7, and a pneumatic valve 10 is installed on the main branch pipeline to realize the switching of the pipeline between the evaporative cold soft water tank 7 and the converter soft water tank 2; a pneumatic valve 10 is installed on the pipeline at the top of the evaporative cold soft water tank.

[0028] Furthermore, an interlock is added between the opening and closing of the pneumatic valve on top of converter soft water tank 2 and the water level in the converter soft water tank. This is set in the pneumatic valve control program so that the interlocked water level range is higher than the company's automatic water replenishment range. For example, the automatic water replenishment level of the demineralized water in the pipeline is adjusted from 2000mm to 1500mm (automatic water replenishment below 1500mm), and the pneumatic valve is set to open to replenish water to the tank when the water level in the converter soft water tank is lower than the high water level (3500mm), and to close to stop replenishing water to the tank when the water level reaches the high high water level (3950mm).

[0029] Furthermore, heat exchanger 4 was changed from a rubber-sealable plate heat exchanger to a welded plate heat exchanger, and the heat exchange area was increased from 198m². 2 Increased to 310m 2 The maximum pressure increased from 1.6 MPa to 2.0 MPa.

[0030] The specific settings are as follows:

[0031] (a) Confirming the feasibility of using steam condensate for vaporization cooling systems

[0032] 1. The steam condensate originates from the steam condensate A generated by the vaporization cooling system. Reusing the steam condensate in the vaporization cooling system is essentially a recycling process. Therefore, the steam condensate has the potential to replace demineralized water in the vaporization cooling system.

[0033] 2. Sampling devices 9 were installed in the heat accumulator 3 and the recovery water tank 5 to collect steam condensate water samples from the heat storage station. These samples were sent to a testing department for professional water quality analysis. Based on the comparative analysis of the test results, the feasibility of using steam condensate water for the vaporization cooling system was confirmed. This was the sampling analysis before use. After confirming its feasibility, multiple sampling points were no longer needed, and water quality monitoring could be performed periodically thereafter.

[0034] (ii) Lay pipelines to transport water from the thermal storage station's recovery tank to the converter's soft water tank.

[0035] 1. Considering the actual operating conditions, the heat storage station's recovery water tank 5 is quite far from the converter's soft water tank 2, separated by multiple spans and columns. The on-site production is intertwined, making pipeline laying extremely difficult. Furthermore, the existing pipeline scaffolding is densely packed, leaving limited operating space. Considering the construction difficulty and cost, existing pipelines will be fully utilized by adding branch pipelines to the pipeline from the heat storage station's recovery water tank to the evaporative cooling soft water tank, delivering water to the No. 1 and No. 2 shared soft water tanks and the No. 3 converter soft water tank. Figure 1 Only the connecting pipe 8 from the recycled water tank to the soft water tank is shown.

[0036] 2. Install a pneumatic valve on the main branch pipeline to switch the pipeline between the evaporative cooling water tank and the converter soft water tank. When there is a surplus of steam condensate or the industrial fresh water supply system of the evaporative cooling water tank fails, the steam condensate from the recovery water tank 5 will be sent to the evaporative cooling soft water tank (to replace fresh water as emergency replenishment water), so as to achieve efficient use of resources and ensure the stable operation of the evaporative cooling system.

[0037] 3. Install a pneumatic valve on the top pipeline of the soft water tank to switch the pipeline between the No. 1 and No. 2 common soft water tanks and the No. 3 converter soft water tank, so as to coordinate and meet the water supply needs of different furnace bases and different operating conditions.

[0038] (iii) Adjust parameters and add interlocks to ensure that the converter soft water tank prioritizes the use of recovered steam condensate.

[0039] 1. Adjust the water supply parameters of the evaporative cooling water tank, changing the interlock parameter for the steam condensate water supply level from being higher than the industrial fresh water supply level interlock parameter to being lower than the industrial fresh water supply level interlock parameter. When the water level in the evaporative cooling water tank drops, switch from prioritizing the use of steam condensate water to prioritizing the use of industrial fresh water.

[0040] 2. Add an interlock between the opening and closing of the pneumatic valve on the top of the converter soft water tank and the water level of the converter soft water tank. When the water level of the converter soft water tank is lower than the high water level (3500mm), the pneumatic valve opens to replenish water to the tank. When the water level reaches the high high water level (3950mm), the pneumatic valve closes to stop replenishing water to the tank.

[0041] 3. Adjust the water supply parameters of the converter soft water tank, and lower the interlock parameter of the demineralized water supply level of the company's pipeline from 2000mm to 1500mm, which is lower than the interlock parameter of 3500mm for steam condensate water replenishment level. This will enable the steam condensate to be used to replenish the soft water tank first, while retaining the demineralized water supply function of the company's official website when the steam condensate is insufficient or the system fails.

[0042] (iv) Upgrading and retrofitting heat exchangers

[0043] To meet the water temperature requirements of the vaporization cooling system and ensure stable operation of the heat exchange system, the heat exchanger was upgraded. Based on operating conditions and recycling requirements, the heat exchanger was changed from a rubber-sealable plate heat exchanger to a welded plate heat exchanger, increasing the heat exchange area from 198 m². 2 Increased to 310m 2 The maximum pressure has been increased from 1.6MPa to 2.0MPa, improving its impact resistance, heat exchange capacity, and temperature and pressure resistance. The system is installed in parallel with the existing heat exchanger, allowing the original heat exchanger to be retained for maintenance and backup. This ensures the stable operation of the heat exchange system while meeting the water temperature requirements of the vaporization cooling system.

[0044] (v) Water quality monitoring

[0045] Water quality is one of the key factors affecting the safe operation of vaporization cooling systems; therefore, monitoring the water quality of steam condensate is crucial. Firstly, the water quality testing contractor regularly samples, tests, and analyzes the water in the recovery water tank and soft water tank. If any water quality indicators are found to be non-compliant, measures such as wastewater discharge and replenishment with demineralized water are promptly taken to ensure water quality stability. The table below shows the water quality test data for this embodiment:

[0046]

[0047] The working principle of this utility model:

[0048] When using this invention, the modified heat exchanger for the steam condensate from the thermal storage station lowers the condensate temperature to an appropriate level before sending it to the recovery water tank. The recovery water pump starts when the water level in the recovery water tank reaches the high level. When the water level in the two soft water tanks is below the high level, the control valve of the condensate water supply pipeline opens to replenish the soft water tanks. When the water level reaches the high-high level, the control valve of the condensate water supply pipeline closes. When the water levels in both soft water tanks reach the high-high level, the control valve of the condensate water supply pipeline to the evaporative cooling water tank opens to replenish the evaporative cooling water tank. The valve closes when the water level reaches the high-high level. In special circumstances, when the water levels in all three tanks reach the high-high level, the recovery water pump stops. The converter soft water tank and the evaporative cooling water tank retain the original company network water supply function, automatically replenishing water when the water level is below the low level (network water supply level). This achieves the goal of prioritizing the use of steam condensate from the thermal storage station to replace demineralized water in the vaporization cooling system, and using surplus water as fresh industrial water for evaporative cooling.

Claims

1. A device for optimizing the utilization of steam condensate from a steel plant thermal storage station, characterized in that: Includes sampling device, heat accumulator, heat exchanger, recovery water tank, and pipeline connecting the recovery water tank and soft water tank; Sampling devices are installed on the heat accumulator and the recovery water tank, including sampling pipes and sampling valves, for water quality testing of steam condensate. The connection pipeline between the recovery water tank and the soft water tank is a recovery and control pipeline installed between the heat accumulator recovery water tank and the converter soft water tank, which sends the steam condensate to the converter soft water tank for recycling. A pneumatic valve is added to the connection pipeline between the recovery water tank and the soft water tank, and by controlling the opening and closing of the valve, the converter soft water tank is given priority to use the recovered steam condensate. The heat exchanger is a welded plate heat exchanger.

2. The device for optimizing the utilization of steam condensate from a steel plant thermal storage station according to claim 1, characterized in that: An interlock is installed on the water tank to start and stop the water pump. The water pump starts to collect water when the water level in the tank reaches the high level and stops when the water level is lower than the low level. The water pump is allowed to start when the water temperature in the tank is lower than the alarm value, but is not allowed to start when the water temperature is higher than the alarm value.

3. The device for optimizing the utilization of steam condensate from a steel plant thermal storage station according to claim 1, characterized in that: Branch pipelines are installed between the heat storage station's recovery water tank and the evaporative cooling soft water tank. Pneumatic valves are installed on the main branch pipelines to allow the pipelines to switch between the evaporative cooling soft water tank and the converter soft water tank. Pneumatic valves are also installed on the pipelines at the top of the soft water tanks.

4. The device for optimizing the utilization of steam condensate from a steel plant thermal storage station according to claim 1, characterized in that: An interlock is added between the opening and closing of the pneumatic valve on the top of the converter soft water tank and the water level of the converter soft water tank. The pneumatic valve is set to open to replenish water to the tank when the water level of the converter soft water tank is lower than the high water level.

5. The device for optimizing the utilization of steam condensate from a steel plant thermal storage station according to claim 1, characterized in that: The heat exchanger's heat exchange area can reach 310m² 2 The maximum pressure can reach 2.0 MPa.

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