Stepping beam type heating furnace waste heat recovery system

Abstract

The utility model belongs to the technical field of heating furnace waste heat recovery, and relates to a walking beam type heating furnace waste heat recovery system which comprises a low-pressure steam pocket, a low-pressure circulating pump, a water inlet stepping device, a heating furnace movable water beam and a low-pressure circulating loop formed by connecting a water outlet stepping device through pipelines. The high-pressure steam pocket, the high-pressure circulating pump and the heating furnace fixed water beam are connected through pipelines to form a high-pressure circulating loop; one part of hot water in the low-pressure steam pocket is pressurized by a water feeding pump, is heated by an economizer arranged in a heating furnace flue and then is fed into the high-pressure steam pocket; one part of low-pressure saturated steam generated by the low-pressure steam pocket is fed into a pressure deaerator communicated with the low-pressure steam pocket for thermal deaeration, and the other part of the low-pressure saturated steam is fed to a low-pressure steam user; and high-pressure saturated steam generated by the high-pressure steam pocket enters a steam superheater arranged in a flue of the heating furnace to be heated into high-pressure superheated steam, and the high-pressure superheated steam is sent to a high-pressure steam user.

Description

TECHNICAL FIELD

[0001] The utility model belongs to heating furnace waste heat recovery technical field relates to a kind of walking beam type heating furnace waste heat recovery system. BACKGROUND

[0002] Heating furnace vaporization cooling technology as a mature technology in walking beam type heating furnace waste heat recovery system, with its water consumption, water beam service life is long and can produce recyclable steam and other multiple advantages, has been widely applied in industrial production.Its system flow design is ingenious, specific process is as follows (system structure schematic diagram, see attached Figure 1 ):

[0003] First, make-up water (usually soft water or desalted water) is sent into atmospheric thermal deaerator 1 to carry out deaeration treatment, to remove dissolved oxygen in water, to prevent system equipment from being corroded by oxygen.The make-up water after deaeration is then stored in deaerated water tank 2.Subsequently, after being boosted by feed water pump 3, the make-up water is sent into steam drum 4 and fully mixed with circulating water in steam drum 4.

[0004] The mixed circulating water is pressurized by circulating pump 5 and is respectively delivered to heating furnace fixed water beam 6 and heating furnace movable water beam 7 of heating furnace, to effectively cool the two parts of water beam.In the cooling process, circulating water absorbs heat and gradually becomes steam-water mixture, and returns to steam drum 4 through pipeline.

[0005] In the steam drum, the steam-water mixture undergoes steam-water separation process, and the separated water continues to be extracted by circulating pump 5 for the next round of circulating cooling.The separated saturated steam has two purposes: one part is sent to the plant steam pipe network for use in other processes or directly discharged into the atmosphere;the other part is sent back to atmospheric thermal deaerator 1 for heating make-up water, to realize energy recycling.

[0006] However, the existing heating furnace vaporization cooling system still has some deficiencies in actual application:

[0007] Firstly, the waste heat recovery efficiency needs to be improved.The current system mainly recovers the heat of heating furnace water beam, but the large amount of waste heat contained in heating furnace flue gas cannot be effectively utilized, which leads to energy waste.

[0008] Secondly, the produced steam quality is relatively low.The pressure and temperature of steam are important indicators to measure its quality.Due to the limitation of walking device, the steam pressure of vaporization cooling system cannot be set too high, and the general working pressure is between 0.5MPa and 1.6MPa.Correspondingly, the steam temperature is also low, which limits the application range of steam.

[0009] Thirdly, the steam use is limited. The saturated steam generated by the vaporization cooling system needs to be used after a small amount is used for thermal deaeration of the system itself. However, due to the low quality of the steam, only low-quality needs such as heating and purging can be met, resulting in frequent excess of the steam, which has to be discharged into the atmosphere, thereby wasting energy and polluting the environment.

[0010] Fourthly, the system is susceptible to oxygen corrosion. The atmospheric thermal deaerator used in the system has a low working pressure (only 0.02 MPa), and the deaeration effect is limited. After the deaerated water with a high oxygen content enters the system, the equipment and pipelines are susceptible to oxygen corrosion, thereby shortening the service life of the system.

[0011] In summary, although the existing heating furnace vaporization cooling system has certain technical foundation and application effect, there are still many aspects to be improved to meet the needs of more efficient and more environmentally friendly industrial production. Therefore, it is particularly important to make technical innovation and optimization and upgrading on the heating furnace vaporization cooling system. Content of the utility model

[0012] Therefore, the utility model aims at providing a walking beam type heating furnace waste heat recovery system, which has the advantages of high steam quality, wide steam use and long service life, so as to solve the problems of the walking beam type heating furnace waste heat recovery system in the background art.

[0013] To achieve the above-mentioned purpose, the utility model provides the following technical scheme:

[0014] A walking beam type heating furnace waste heat recovery system, comprising a low-pressure drum, a high-pressure drum, a pressure deaerator, a low-pressure circulating pump, a high-pressure circulating pump, a feed water pump, a water inlet walking device, a water outlet walking device, a heating furnace fixed water beam, a heating furnace movable water beam, a steam superheater and an economizer.

[0015] The low-pressure drum, the low-pressure circulating pump, the water inlet walking device, the heating furnace movable water beam and the water outlet walking device are connected by pipelines to form a low-pressure circulating loop.

[0016] The high-pressure drum, the high-pressure circulating pump and the heating furnace fixed water beam are connected by pipelines to form a high-pressure circulating loop.

[0017] A part of hot water in the low-pressure drum is pressurized by the feed water pump and sent into the high-pressure drum after being heated by the economizer arranged in the heating furnace flue.

[0018] A part of the low-pressure saturated steam generated by the low-pressure drum is sent into the pressure deaerator in communication with the low-pressure drum for thermal deaeration, and another part is sent to a low-pressure steam user.

[0019] The high-pressure saturated steam generated by the high-pressure drum enters a steam superheater arranged in the flue of the heating furnace to be heated into high-pressure superheated steam, and is sent to a high-pressure steam user.

[0020] Further, an evaporator is arranged in the flue of the heating furnace, and the evaporator is connected in parallel or series with the fixed water beam of the heating furnace to access the high-pressure circulation loop.

[0021] Further, the steam superheater, the evaporator and the economizer are arranged in the flue of the heating furnace in sequence along the flow direction of the flue gas to recover the waste heat of the flue gas.

[0022] Further, the low-pressure drum and the high-pressure drum are respectively used for steam-water separation of low-pressure steam-water mixture and high-pressure steam-water mixture and storage of circulating water.

[0023] Further, the working pressure of the low-pressure drum is set to be between 0.5 MPa and 1.6 MPa.

[0024] Further, the working pressure of the pressure deaerator is consistent with that of the low-pressure drum, which is between 0.5 MPa and 1.6 MPa.

[0025] Further, the number of the low-pressure circulation pump, the high-pressure circulation pump and the feed water pump is set to be one or more arranged in parallel.

[0026] Further, the driving device of the low-pressure circulation pump, the high-pressure circulation pump and the feed water pump is an electric motor, a diesel engine or a steam turbine.

[0027] The beneficial effects of the utility model lie in:

[0028] 1. Efficient waste heat recovery, significant energy saving

[0029] The step-beam type heating furnace waste heat recovery system of the utility model improves the waste heat recovery efficiency significantly through the innovative double circulation loop design. The system can not only absorb the heat of the fixed water beam and the movable water beam of the heating furnace, but also fully utilize the large amount of waste heat in the flue gas of the heating furnace by arranging the steam superheater, the evaporator and the economizer in the flue. Compared with the limitation of the traditional system that only recovers the heat of the water beam, the present scheme realizes the comprehensive utilization of the water beam and the flue gas waste heat, effectively reducing the energy waste. This optimization design reflects the innovativeness of the technical scheme in the field of energy saving, and provides an efficient energy recovery means for industrial production.

[0030] 2. Excellent steam quality, high application value

[0031] The technical solution realizes a breakthrough in steam quality. The system generates a small amount of low-pressure saturated steam through a low-pressure circulation loop, which is mainly used for its own deoxygenation demand, and the external delivery amount is extremely small. The high-pressure circulation loop generates a large amount of high-pressure high-temperature superheated steam, which is significantly better than the low-pressure steam (pressure is only 0.5-1.6 MPa) of the traditional vaporization cooling system. The generation of high-quality superheated steam benefits from the application of a steam superheater, which further heats the high-pressure saturated steam. This innovation not only solves the problem of low steam quality and limited application of the traditional system, but also lays a foundation for downstream high-value-added applications, and shows its practicality in the industrial field.

[0032] 3. Steam has multiple uses and strong adaptability

[0033] Thanks to the characteristics of high-quality superheated steam, the system has wide adaptability in steam utilization. High-pressure superheated steam can be directly used for steam turbine power generation, mechanical processing and other high-demand scenarios, improving energy utilization efficiency. At the same time, through pressure reduction processing, it can also meet the low-quality demand for heating, refrigeration, heat tracing, etc., taking into account various industrial uses. Compared with the disadvantages of excess steam of the traditional system that needs to be discharged, this scheme avoids energy waste and environmental pollution through quality improvement and use expansion. This flexibility not only reflects the practical value of the technical solution, but also makes it have stronger market competitiveness in different industrial scenarios.

[0034] 4. Strong corrosion resistance, long system life

[0035] The system has a significant advantage in durability. By using a pressure deaerator instead of a traditional atmospheric deaerator, the deoxygenation effect is greatly improved. The working pressure of the pressure deaerator is consistent with that of the low-pressure drum (0.5-1.6 MPa), compared with the traditional 0.02 MPa low-pressure deaerator, the deoxygenation capacity is greatly enhanced, effectively reducing the dissolved oxygen content in the water, reducing the risk of oxygen corrosion of equipment and pipelines. This design innovation prolongs the service life of the system, reduces maintenance costs, fully embodies the practicality of the technical solution in reliability and economy, and provides protection for the long-term stable operation of industrial production.

[0036] Other advantages, objects and features of the present utility model will be described to some extent in the subsequent specification, and to some extent, it will be obvious to those skilled in the art based on the study of the following text or can be taught from the practice of the present utility model. The objects and other advantages of the present utility model can be achieved and obtained through the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to make the purpose, technical scheme and advantages of the present utility model more clear, the following will make a preferred detailed description of the present utility model combined with the drawings, in which:

[0038] Figure 1 Figure 1 is a structural schematic diagram of a step-beam heating furnace waste heat recovery system in the background art;

[0039] Figure 2 Figure 2 is a structural schematic diagram of a step-beam heating furnace waste heat recovery system in an embodiment.

[0040] Figure 1 is a structural schematic diagram of a step-beam heating furnace waste heat recovery system in the background art; DETAILED DESCRIPTION

[0041] The embodiments of the present application will be described in detail with specific examples. Other advantages and effects of the present application can be easily understood by those skilled in the art from the content disclosed in the present specification. The present application can also be implemented or applied in other different embodiments, and various modifications or changes can be made to the details in the present specification based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of the present application, and the features in the following embodiments and embodiments can be combined with each other without conflict.

[0042] It should be noted that the drawings are only used for illustrative description, and the representation is only a schematic diagram, not a physical diagram, and should not be understood as a limitation on the present application. In order to better illustrate the embodiments of the present application, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual product size. It is understandable for those skilled in the art that some well-known structures and their descriptions in the drawings may be omitted.

[0043] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that if the terms "upper", "lower", "left", "right", "front", "back" and the like indicate the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, therefore the terms describing the positional relationship in the drawings are only used for illustrative description, and cannot be understood as a limitation on the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0044] Embodiment 1

[0045] Please refer to Figure 2The application discloses a kind of step beam heating furnace waste heat recovery system, including low-pressure drum 9, high-pressure drum 10, pressure deaerator 11, low-pressure circulating pump 12, high-pressure circulating pump 13, feed water pump 3, water inlet step device 8.1, water outlet step device 8.2, heating furnace fixed water beam 6, heating furnace movable water beam 7, steam superheater 14, evaporator 15 and coal economizer 16, each component is connected by pipeline to form complete waste heat recovery system;

[0046] Wherein, the low-pressure drum 9, low-pressure circulating pump 12, water inlet step device 8.1, heating furnace movable water beam 7 and water outlet step device 8.2 are connected by pipeline to form low-pressure circulation loop;

[0047] The high-pressure drum 10, high-pressure circulating pump 13, heating furnace fixed water beam 6 and evaporator 15 are connected by pipeline in series to form high-pressure circulation loop;

[0048] Part of hot water in the low-pressure drum 9 is pressurized by feed water pump 3, heated after being arranged in the heating furnace flue coal economizer 16, and then sent to high-pressure drum 10;

[0049] Low-pressure saturated steam generated by the low-pressure drum 9 is partially sent to the pressure deaerator 11 communicated with the low-pressure drum 9 to perform thermal deaeration, and the other part is sent to a low-pressure steam user, and the pressure deaerator 11 has a water inlet connected with a water supply pipe network to supply water to the system;

[0050] High-pressure saturated steam generated by the high-pressure drum 10 enters the steam superheater 14 arranged in the heating furnace flue to be heated into high-pressure superheated steam, and then is sent to a high-pressure steam user.

[0051] System structure and working process are as follows:

[0052] Low-pressure circulation loop:

[0053] Water (soft water or desalted water) from a water supply pipe network in a factory flows into the pressure deaerator 11, mixes with low-pressure saturated steam generated by the low-pressure drum 9 to perform thermal deaeration, and forms deaerated water. The deaerated water flows into the low-pressure drum 9 and mixes with low-pressure circulating water. The low-pressure circulating water is pressurized by the low-pressure circulating pump 12, and then is sent to the heating furnace movable water beam 7 through the water inlet step device 8.1. In the heating furnace movable water beam 7, the circulating water absorbs heat to form a steam-water mixture, and then returns to the low-pressure drum 9 through the water outlet step device 8.2. In the low-pressure drum 9, the steam-water mixture is separated, the separated water continues to circulate, and the separated low-pressure saturated steam is partially sent to the pressure deaerator 11 for deaeration and the other part is sent to a low-pressure steam user in the factory. In the embodiment, the working pressure of the low-pressure drum 9 and the pressure deaerator 11 is set to 0.5 MPa.

[0054] High-pressure circulation loop:

[0055] Part of the hot water in the low-pressure drum 9 is pressurized by the feed water pump 3 and sent to the economizer 16 arranged at the tail of the heating furnace flue, and after absorbing the waste heat of the flue gas, enters the high-pressure drum 10. The high-pressure circulating water in the high-pressure drum 10 is pressurized by the high-pressure circulating pump 13 and sent to the heating furnace fixed water beam 6 and the evaporator 15 in turn. In the heating furnace fixed water beam 6 and the evaporator 15, the circulating water absorbs heat to form a steam-water mixture, which returns to the high-pressure drum 10 for steam-water separation. The separated high-pressure saturated steam enters the steam superheater 14 arranged in the heating furnace flue, is heated into high-pressure superheated steam, and is sent to the plant area high-pressure steam user (such as a steam turbine generator). In this embodiment, the evaporator 15 and the heating furnace fixed water beam 6 are connected in parallel to the high-pressure circulating loop.

[0056] Flue gas waste heat recovery:

[0057] The steam superheater 14, the evaporator 15 and the economizer 16 are arranged in the flue of the heating furnace along the flow direction of the flue gas. The steam superheater 14 is located in the high-temperature region of the flue, the evaporator 15 is next, and the economizer 16 is located in the low-temperature region of the flue, so as to efficiently recover the waste heat of the flue gas.

[0058] Pump configuration:

[0059] In this embodiment, one low-pressure circulating pump 12, one high-pressure circulating pump 13 and one feed water pump 3 are provided, and all are driven by electric motors.

[0060] This embodiment realizes the comprehensive recovery of the water beam and the flue gas waste heat through the design of the low-pressure and high-pressure double circulating loops and the combination of the heat exchange equipment (steam superheater 14, evaporator 15 and economizer 16) in the flue. The working pressures of the low-pressure drum 9 and the pressure deaerator 11 are consistent, which ensures good deaeration effect and reduces oxygen corrosion; the high-pressure superheated steam has high quality and is suitable for various industrial uses.

[0061] Embodiment 2

[0062] Compared with embodiment 1, the number and working pressure of the pumps are adjusted in this embodiment, and the specific structure and working process are as follows:

[0063] Low-pressure circulating loop:

[0064] The make-up water enters the pressure deaerator 11 and mixes with the low pressure saturated steam generated by the low pressure drum 9 to perform thermal deaeration, and then forms deaerated water which flows into the low pressure drum 9. The low pressure circulating water is pressurized by two parallel arranged low pressure circulating pumps 12, sequentially passes through the water inlet stepping device 8.1, the movable water beam 7 of the heating furnace and the water outlet stepping device 8.2, forms a steam-water mixture and then returns to the low pressure drum 9. In the low pressure drum 9, the steam-water mixture is separated into water and low pressure saturated steam. Part of the separated steam is sent to the pressure deaerator 11, and the other part is sent to the low pressure steam user. In this embodiment, the working pressure of the low pressure drum 9 and the pressure deaerator 11 is set to 1.6 MPa to meet the higher deaeration requirement.

[0065] High pressure circulating loop:

[0066] Part of the hot water in the low pressure drum 9 is pressurized by two parallel arranged feed water pumps 3, enters the economizer 16 to absorb the flue gas waste heat, and then enters the high pressure drum 10. The high pressure circulating water is pressurized by two parallel arranged high pressure circulating pumps 13, and is sent to the fixed water beam 6 of the heating furnace and the evaporator 15 (in parallel) respectively. In the fixed water beam 6 of the heating furnace and the evaporator 15, the circulating water absorbs heat to form a steam-water mixture, which returns to the high pressure drum 10 for steam-water separation. The separated high pressure saturated steam enters the steam superheater 14, is heated into high pressure superheated steam, and then is sent to the high pressure steam user. In this embodiment, the evaporator 15 and the fixed water beam 6 of the heating furnace are connected in parallel to the high pressure circulating loop.

[0067] Flue gas waste heat recovery:

[0068] The same as in embodiment 1, the steam superheater 14, the evaporator 15 and the economizer 16 are arranged in the heating furnace flue from inside to outside in sequence, to ensure efficient recovery of flue gas waste heat.

[0069] Pump configuration:

[0070] In this embodiment, two parallel arranged low pressure circulating pumps 12, high pressure circulating pumps 13 and feed water pumps 3 are provided respectively, and all are driven by steam turbines to improve the stability and flexibility of system operation.

[0071] In this embodiment, the number of parallel pumps is increased and steam turbine driving is adopted, which improves the flow processing capacity and operation reliability of the system. The working pressure of the low pressure drum 9 and the pressure deaerator 11 is increased to 1.6 MPa, which further enhances the deaeration effect and prolongs the service life of the equipment. The superheated steam generated by the high pressure circulating loop can meet the industrial application requirements of higher pressure and temperature.

[0072] Finally, it is explained that the above embodiments are only used to illustrate the technical solutions of the present application and are not limited. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A waste heat recovery system for a walking beam furnace, characterized in that: It includes a low-pressure steam drum, a high-pressure steam drum, a pressure deaerator, a low-pressure circulating pump, a high-pressure circulating pump, a feed water pump, an inlet stepping device, an outlet stepping device, a fixed water beam for the heating furnace, a movable water beam for the heating furnace, a steam superheater, and an economizer. The low-pressure steam drum, low-pressure circulating pump, water inlet stepping device, heating furnace movable water beam and water outlet stepping device are connected by pipelines to form a low-pressure circulating loop; The high-pressure steam drum, high-pressure circulating pump, and fixed water beam of the heating furnace are connected by pipelines to form a high-pressure circulating loop. A portion of the hot water in the low-pressure steam drum is pressurized by a feedwater pump, heated by an economizer arranged in the boiler flue, and then sent into the high-pressure steam drum. A portion of the low-pressure saturated steam generated by the low-pressure steam drum is sent to a pressure deaerator connected to the low-pressure steam drum for thermal deaeration, and the other portion is sent to low-pressure steam users. The high-pressure saturated steam generated by the high-pressure steam drum enters the steam superheater arranged in the flue of the heating furnace and is heated into high-pressure superheated steam, which is then sent to the high-pressure steam user.

2. The waste heat recovery system for a walking beam furnace according to claim 1, characterized in that: It also includes an evaporator arranged in the flue of the heating furnace, and the evaporator is connected in parallel or in series with the fixed water beam of the heating furnace to access the high-pressure circulation loop.

3. The waste heat recovery system for a walking beam furnace according to claim 2, characterized in that: The steam superheater, evaporator, and economizer are arranged sequentially along the flue gas flow direction in the heating furnace flue to recover waste heat from the flue gas.

4. The waste heat recovery system for a walking beam furnace according to claim 1, characterized in that: The low-pressure steam drum and the high-pressure steam drum are used for steam-water separation of low-pressure steam-water mixture and high-pressure steam-water mixture, and for the storage of circulating water, respectively.

5. The waste heat recovery system for a walking beam furnace according to claim 1, characterized in that: The working pressure of the low-pressure steam drum is set between 0.5 MPa and 1.6 MPa.

6. The waste heat recovery system for a walking beam furnace according to claim 5, characterized in that: The operating pressure of the pressure deaerator is the same as that of the low-pressure steam drum, ranging from 0.5 MPa to 1.6 MPa.

7. The waste heat recovery system for a walking beam furnace according to claim 1, characterized in that: The number of low-pressure circulating pumps, high-pressure circulating pumps, and water supply pumps is set to one or more units arranged in parallel.

8. The waste heat recovery system for a walking beam furnace according to claim 1, characterized in that: The driving devices for the low-pressure circulating pump, high-pressure circulating pump, and feedwater pump are electric motors, diesel engines, or steam turbines.

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