Waste heat recovery device based on steel slag pressure hot braising process

Abstract

The utility model provides a waste heat recovery device based on a steel slag pressure hot braising process. The waste heat recovery device comprises a heat accumulating type heat exchanger and a plate type heat exchanger. The heat source input end of the heat accumulating type heat exchanger is communicated with the steam output end of the slag braising tank, the heat medium water output end of the heat accumulating type heat exchanger is communicated with the heat source side input end of the plate heat exchanger, and the heat medium water output end of the heat accumulating type heat exchanger is communicated with the heat source side input end of the plate heat exchanger; the heat source side input end of the plate heat exchanger is communicated with the heat medium water output end of the heat accumulating type heat exchanger, and the heat source side output end of the plate heat exchanger is communicated with the heat medium water input end of the heat accumulating type heat exchanger. According to the waste heat recovery device based on the steel slag pressure hot braising technology, zero emission of slag braising steam to the air can be achieved, slag braising waste heat is recovered, and the environment is protected against pollution.

Description

Technical Field

[0001] This application relates to the field of steel slag treatment, and in particular to a waste heat recovery device based on a pressurized hot quenching process for steel slag. Background Technology

[0002] Currently, the steel industry uses the fourth-generation pressurized hot quenching process to realize the resource utilization of steel slag in converter steel slag treatment. The process consists of two stages: steel slag roller crushing and steel slag pressurized hot quenching.

[0003] During the pressurized slag curing stage, water is sprayed into a sealed slag curing tank. The water cools the steel slag while being heated by the residual heat of the high-temperature steel slag, turning it into low-pressure saturated steam. The flow rate and pressure of this steam fluctuate greatly, concentrated in the first hour of water spraying. In the second 1.5 to 2 hours, the steam output is very small, or even interrupted. Furthermore, this steam contains many impurities, including a large amount of alkaline dust particles, air, and hydrogen. The alkaline dust particles easily form scale, adhering to the equipment and corroding the metal. The air and hydrogen reduce the quality of the steam, making recovery and treatment difficult.

[0004] Furthermore, when the low-pressure saturated steam generated by heating the waste heat of high-temperature steel slag is utilized, the heat generated during the hot curing process is intermittent and discontinuous, making it impossible to achieve a stable heat source supply. The steam pressure generated during curing is not high, and the temperature of the curing steam and circulating water is not high. In addition, the cleanliness of the steam and circulating water is very poor, containing a large number of alkaline impurities, which easily cause scaling and blockage of pipes, and will also have a corrosive effect on metals. Therefore, it cannot be used directly.

[0005] In existing technologies, the low-pressure saturated steam generated by heating the waste heat of high-temperature steel slag is usually discharged directly. A steam collection hood is installed, and a fan is used to extract the steam to exhaust it into the air. Although this method reduces the impact of steam on production operations, a large amount of waste heat is not fully utilized, water resources are wasted, and the surrounding environment is polluted. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a waste heat recovery device based on the pressurized hot slag quenching process, which can achieve zero emission of quenching steam into the air, recover the waste heat from quenching, and protect the environment from pollution.

[0007] To achieve the objectives of this application, the following technical solution is provided:

[0008] This application provides a waste heat recovery device based on the pressurized hot quenching process of steel slag, including: a regenerative heat exchanger and a plate heat exchanger;

[0009] The heat source input end of the regenerative heat exchanger is connected to the steam output end of the slag-steaming tank, the heat medium water output end is connected to the heat source side input end of the plate heat exchanger, and the heat medium water input end is connected to the heat source side output end of the plate heat exchanger.

[0010] The heat source side input terminal of the plate heat exchanger is connected to the heat medium water output terminal of the regenerative heat exchanger, and the heat source side output terminal is connected to the heat medium water input terminal of the regenerative heat exchanger.

[0011] In one possible implementation, the regenerative heat exchanger is connected to the slag-suppressing tank via a main steam pipe, and the main steam pipe has a steam filter.

[0012] In one possible implementation, a circulating water pump is provided on the pipeline between the heat medium water output end of the regenerative heat exchanger and the heat source side input end of the plate heat exchanger.

[0013] In one possible implementation, the regenerative heat exchanger is connected to a water source via a water supply pipe, which has a water supply electric valve.

[0014] In one possible implementation, the bottom of the regenerative heat exchanger also has a drain pipe with a drain electric valve.

[0015] In one possible implementation, the waste heat recovery device based on the pressurized hot quenching process of steel slag further includes: a PLC control module; the PLC control module includes: a liquid level sensor and a PLC control unit;

[0016] The liquid level sensor is installed inside the regenerative heat exchanger and is used to detect the liquid level height inside the regenerative heat exchanger.

[0017] The PLC control unit is connected to the liquid level sensor and the water replenishment electric valve, and is used to control the water replenishment electric valve to open when the liquid level in the heat exchanger is less than a first preset value, and to control the water replenishment electric valve to close when the liquid level in the heat exchanger is greater than or equal to the first preset value.

[0018] In one possible implementation, the PLC control unit is also connected to the drain electric valve, and is used to control the drain electric valve to open when the liquid level in the regenerative heat exchanger is greater than a second preset value, and to control the drain electric valve to close when the liquid level in the regenerative heat exchanger is less than or equal to the second preset value.

[0019] In one possible implementation, the PLC control unit includes: a first control element, a second control element, a third control element, and a fourth control element;

[0020] The first control element is used to control the water replenishment electric valve to open when the received liquid level height value is less than a first preset value;

[0021] The second control element is used to control the water supply electric valve to close when the received liquid level height value is greater than or equal to a first preset value;

[0022] The third control element is used to control the drain electric valve to open when the received liquid level height value is greater than the second preset value.

[0023] The fourth control element is used to control the drain electric valve to close when the received liquid level height value is less than or equal to a second preset value.

[0024] In one possible implementation, the circulating water pump includes: a first circulating water pump and a second circulating water pump; the second circulating water pump is used to automatically start when the first circulating water pump trips.

[0025] In one possible implementation, the regenerative heat exchanger also has a scale prevention and removal device.

[0026] Beneficial effects:

[0027] The waste heat recovery device based on the pressurized hot slag quenching process provided in this application can utilize the heat medium water in the regenerative heat exchanger as the heat storage medium. It adopts the method of direct mixing and heat exchange between the slag quenching steam and the heat medium water, which has a large contact area, high heat exchange efficiency, and is simple and easy to implement. At the same time, the water temperature of the regenerative heat exchanger remains stable within a certain range, which plays a role in regulating the water temperature and realizing a stable supply of heat source.

[0028] After six months of use and on-site commissioning, the maximum temperature of the heat transfer water can reach 95℃, and the system can operate continuously and stably. Furthermore, the slag steam direct mixing heat exchange system and the secondary utilization system exchange heat through a heat exchanger. The water in the two systems is not interconnected, so the circulating water in the secondary utilization system can always be kept clean, solving the problem of poor slag water quality that cannot be directly used.

[0029] The waste heat recovery device in this application can be implemented by modifying the existing slag curing project. It requires less investment, has a short construction period, is easy to promote in engineering, and can achieve zero emission of slag curing steam into the air, recovering the waste heat of slag curing and protecting the environment from pollution. Attached Figure Description

[0030] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0031] Figure 1This is a schematic diagram of a waste heat recovery device based on a pressurized hot quenching process for steel slag, provided as an embodiment of this application.

[0032] Figure label:

[0033] 1-Steam main pipeline; 2-Steam filter; 3-Steam valve group; 4-Regenerative heat exchanger; 5-Scale prevention and removal device; 6-Circulating water pump; 7-Circulating water pipeline; 8-Plate heat exchanger; 9-PLC control module. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this application, unless otherwise stated, "multiple" means two or more.

[0036] Example 1

[0037] Figure 1 A waste heat recovery device based on the pressurized hot quenching process of steel slag provided in the embodiments of this application includes: a regenerative heat exchanger 4 and a plate heat exchanger 8.

[0038] The heat source input end of the regenerative heat exchanger 4 is connected to the steam output end of the slag-steaming tank, the heat medium water output end is connected to the heat source side input end of the plate heat exchanger 8, and the heat medium water input end is connected to the heat source side output end of the plate heat exchanger 8.

[0039] The heat source side input end of the plate heat exchanger 8 is connected to the hot medium water output end of the regenerative heat exchanger 4, and the heat source side output end is connected to the hot medium water input end of the regenerative heat exchanger 4.

[0040] The heat medium water input end of the regenerative heat exchanger 4 is connected to the heat source side output end of the plate heat exchanger 8 through a circulating water pipe 7.

[0041] Optionally, the input and output ends of the plate heat exchanger 8 on the heat exchange side are used to connect the working fluid input and output ends of the working fluid equipment that needs to be heated.

[0042] In one possible implementation, the regenerative heat exchanger 4 is connected to the slag-smoking tank via a main steam pipe 1, and the main steam pipe 1 is equipped with a steam filter 2.

[0043] Optionally, there are two steam filters 2. When one steam filter fails or needs maintenance and cleaning, the valve of the other filter can be opened for use.

[0044] In one possible implementation, a circulating water pump 6 is provided on the pipeline between the heat medium water output end of the regenerative heat exchanger 4 and the heat source side input end of the plate heat exchanger 8.

[0045] The pipe in question is a circulating water pipe 7.

[0046] In one possible implementation, the regenerative heat exchanger 4 is connected to a water source via a water supply pipe, and the water supply pipe is equipped with a water supply electric valve.

[0047] Optionally, the water supply pipe is located at the top of the heat storage heat exchanger 4, and the water source is positioned higher than the heat storage heat exchanger 4.

[0048] Optionally, the water supply pipe is equipped with a water pump.

[0049] In one possible implementation, the bottom of the regenerative heat exchanger 4 also has a drain pipe with a drain electric valve.

[0050] In one possible implementation, the waste heat recovery device based on the pressurized hot quenching process of steel slag further includes: a PLC control module 9; the PLC control module 9 includes: a liquid level sensor and a PLC control unit;

[0051] The liquid level sensor is installed inside the regenerative heat exchanger 4 and is used to detect the liquid level height inside the regenerative heat exchanger 4.

[0052] The PLC control unit is connected to the liquid level sensor and the water replenishment electric valve, and is used to control the water replenishment electric valve to open when the liquid level in the heat exchanger 4 is less than a first preset value, and to control the water replenishment electric valve to close when the liquid level in the heat exchanger 4 is greater than or equal to the first preset value.

[0053] Optionally, the PLC control unit can be connected to the water supply electric valve and the liquid level sensor in any one or more of the following ways: hard-wired connection, communication connection, and electrical connection.

[0054] Optionally, the liquid level sensor is installed on the hot water tank of the regenerative heat exchanger 4.

[0055] Optionally, the heat storage heat exchanger 4 is also equipped with a temperature sensor and a pressure sensor, which will provide an alarm when the temperature or pressure exceeds a preset warning value.

[0056] In one possible implementation, the PLC control unit is also connected to the drain electric valve, and is used to control the drain electric valve to open when the liquid level in the regenerative heat exchanger 4 is greater than a second preset value, and to control the drain electric valve to close when the liquid level in the regenerative heat exchanger 4 is less than or equal to the second preset value.

[0057] Optionally, the connection method between the PLC control unit and the drain electric valve can be any one or more of hard-wired connection, communication connection, and electrical connection.

[0058] Optionally, the PLC control unit is also used to shut down the circulating water pump and control the alarm module to sound an alarm when the liquid level is less than a third preset value.

[0059] In one possible implementation, the PLC control unit includes: a first control element, a second control element, a third control element, and a fourth control element;

[0060] The first control element is used to control the water replenishment electric valve to open when the received liquid level height value is less than a first preset value;

[0061] The second control element is used to control the water supply electric valve to close when the received liquid level height value is greater than or equal to a first preset value;

[0062] The third control element is used to control the drain electric valve to open when the received liquid level height value is greater than the second preset value.

[0063] The fourth control element is used to control the drain electric valve to close when the received liquid level height value is less than or equal to a second preset value.

[0064] Optionally, the first control element and the second control element are connected to the water supply electric valve, and the third control element and the fourth control element are connected to the drain electric valve.

[0065] The liquid level can be controlled using the PLC control method described above.

[0066] When the liquid level is lower than the normal range, the water supply electric valve will automatically open.

[0067] When the liquid level returns to normal, close the water supply electric valve;

[0068] When the liquid level is higher than the normal set value range, the drain electric valve will open automatically. When the liquid level returns to the normal level, the drain electric valve will close.

[0069] When the liquid level is lower than the minimum liquid level, a low water level alarm is issued and the water supply electric valve is adjusted to increase its capacity. When the liquid level is higher than the maximum liquid level, a high water level alarm is issued and the drain electric valve is adjusted to increase its capacity.

[0070] In one possible implementation, the circulating water pump 6 includes: a first circulating water pump and a second circulating water pump; the second circulating water pump is used to automatically start when the first circulating water pump trips.

[0071] Optionally, the method for automatically starting the second circulating water pump is as follows: using an electrical control system, the control circuits of the first and second circulating water pumps are interlocked. When the first circulating water pump trips, an electrical signal triggers the starting circuit of the second circulating water pump, causing it to start automatically.

[0072] The above control method enables the control of the circulating water pump: when one circulating water pump trips due to an accident, the standby pump is automatically put into operation; when the water replenishment system malfunctions and the liquid level is lower than the low liquid level stop pump setting value, the PLC control interlocks to stop the pump, automatically stops the operation of the circulating water pump and alarms.

[0073] In one possible implementation, the regenerative heat exchanger 4 also has a scale prevention and removal device 5.

[0074] Optionally, the scale prevention and descaling device 5 includes: a mechanical cleaning device, a chemical cleaning device, an ultrasonic cleaning device, and a scale prevention coating.

[0075] The mechanical cleaning device can be installed inside the heat exchanger, such as a brush, scraper, or rinsing nozzle. It removes dirt and deposits by periodically or irregularly cleaning the surface and interior of the heat exchanger.

[0076] The chemical cleaning device can be installed at the inlet and outlet of the heat exchanger, such as a dosing pump, a stirrer, or a chemical cleaning tank. By injecting a chemical cleaning agent into the heat exchanger, it reacts chemically with the dirt, thereby removing the dirt.

[0077] The ultrasonic cleaning device can be installed inside the heat exchanger, such as an ultrasonic transducer or ultrasonic generator. It generates ultrasonic vibrations to loosen and remove dirt.

[0078] The anti-scaling coating can be applied to the inner and outer surfaces of the heat exchanger, such as a polytetrafluoroethylene (PTFE) coating or a ceramic coating. This reduces the adhesion and deposition of fouling, thereby extending the service life of the heat exchanger.

[0079] In one possible implementation, the waste heat recovery device based on the pressurized hot slag quenching process further includes: an alarm module; the alarm module is connected to a level gauge and is used to issue a low water level alarm and increase the pressure of the water supply electric valve when the liquid level is lower than the minimum liquid level value; and to issue a high water level alarm and increase the pressure of the drain electric valve when the liquid level is higher than the maximum liquid level value.

[0080] In the embodiments provided in this application, it should be understood that the disclosed systems, modules, and methods can be implemented in other ways. For example, the module embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between modules or units, and may be electrical, mechanical, or other forms.

[0081] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. This application is not limited to the exact structures described above and illustrated in the accompanying drawings, and it should not be considered that the specific implementation of this application is limited to these descriptions. For those skilled in the art, various changes and modifications made without departing from the concept of this application should be considered to fall within the protection scope of this application.

Claims

1. A waste heat recovery device based on the steel slag hot stewing process, characterized in that: include: Regenerative heat exchanger (4), plate heat exchanger (8); The heat source input end of the heat storage heat exchanger (4) is connected to the steam output end of the slag stewing tank, the heat source input end of the heat storage heat exchanger (4) is connected to the steam output end of the slag stewing tank, the heat medium water output end is connected to the heat source side input end of the plate heat exchanger (8), and the heat medium water input end is connected to the heat source side output end of the plate heat exchanger (8); The heat source side input end of the plate heat exchanger (8) is in communication with the heat medium water output end of the thermal storage heat exchanger (4), and the heat source side output end is in communication with the heat medium water input end of the thermal storage heat exchanger (4).

2. The waste heat recovery device based on the steel slag pressure hot stewing process according to claim 1 is characterized in that: The regenerative heat exchanger (4) is connected to the slag stewing tank via a steam main pipeline (1), and a steam filter (2) is provided on the steam main pipeline (1).

3. The waste heat recovery device based on the steel slag pressure hot stewing process according to claim 1 is characterized in that: A circulating water pump (6) is provided on the pipeline between the heat medium water output end of the heat storage heat exchanger (4) and the heat source side input end of the plate heat exchanger (8).

4. The waste heat recovery device based on the steel slag pressure hot stewing process according to claim 1 is characterized in that: The thermal storage heat exchanger (4) is connected to a water source via a water supply pipe, and the water supply pipe is provided with a water supply electric valve.

5. The waste heat recovery device based on the steel slag pressure hot stewing process according to claim 4 is characterized in that: The bottom of the thermal storage heat exchanger (4) is also provided with a drainage pipe, and the drainage pipe is provided with a drainage electric valve.

6. The waste heat recovery device based on the steel slag pressure hot stewing process according to claim 5 is characterized in that: Also includes: PLC control module (9); The PLC control module (9) comprises: a liquid level sensor and a PLC control unit; The liquid level sensor is arranged in the thermal storage heat exchanger (4) and is used to detect the liquid level height in the thermal storage heat exchanger (4); The PLC control unit is connected to the liquid level sensor and the water replenishment electric valve, and is used to control the water replenishment electric valve to open when the liquid level height value in the thermal storage heat exchanger (4) is less than a first preset value, and is used to control the water replenishment electric valve to close when the liquid level height value in the thermal storage heat exchanger (4) is greater than or equal to the first preset value.

7. The waste heat recovery device based on the steel slag pressure hot stewing process according to claim 6 is characterized in that: The PLC control unit is also connected to the drain electric valve and is used to control the drain electric valve to open when the liquid level height value in the thermal storage heat exchanger (4) is greater than a second preset value, and to control the drain electric valve to close when the liquid level height value in the thermal storage heat exchanger (4) is less than or equal to the second preset value.

8. The waste heat recovery device based on the steel slag pressure hot stewing process according to claim 7 is characterized in that: The PLC control unit includes: a first control element, a second control element, a third control element, and a fourth control element; The first control element is used to control the water replenishment electric valve to open when the received liquid level height value is less than a first preset value; The second control element is used to control the water replenishment electric valve to close when the received liquid level height value is greater than or equal to a first preset value; The third control element is used to control the drain electric valve to open when the received liquid level value is greater than a second preset value; The fourth control element is used to control the drain electric valve to close when the received liquid level height value is less than or equal to a second preset value.

9. The waste heat recovery device based on the steel slag pressure hot stewing process according to claim 3 is characterized in that: The circulating water pump (6) comprises: a first circulating water pump and a second circulating water pump; the second circulating water pump is used to automatically start when the first circulating water pump trips.

10. The waste heat recovery device based on the steel slag autoclave hot stewing process according to claim 1 is characterized in that: The heat storage heat exchanger (4) is also provided with a scale prevention and descaling device (5).

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