Steam generating apparatus

Abstract

Disclosed is a steam generating device capable of avoiding dry burning damage of heat exchange pipes, comprising: a burner; a first heat exchange assembly provided with a combustion chamber for combustion of the burner, defining a first flue gas flow channel and a main heat exchange flow channel; water in the main heat exchange flow channel is partially vaporized by heat exchange with flue gas in the first flue gas flow channel, and a steam-water mixed fluid with a temperature above 90 DEG C is output; a second heat exchange assembly defining a second flue gas flow channel and a steam generating flow channel; the second flue gas flow channel is communicated with the downstream of the first flue gas flow channel in the flue gas flow direction, and the steam generating flow channel is communicated with the downstream of the main heat exchange flow channel in the water flow direction; the steam-water mixed fluid in the steam generating flow channel is heat exchanged with flue gas in the second flue gas flow channel to form steam; and the second heat exchange assembly has a steam output end for outputting steam.

Description

Technical Field

[0001] This disclosure relates to the field of steam generation technology, and more particularly to a steam generation device. Background Technology

[0002] Under the national call for energy conservation and emission reduction, steam generating equipment is accelerating its development towards highly efficient, low-emission, fully premixed condensing steam generators. In particular, the inspection-free / report-free once-through gas-fired steam generators, compared to traditional steam boilers, produce steam faster, are more energy-efficient and environmentally friendly, and do not require installation, inspection, or annual boiler audits. They are widely favored by the market and are extensively used in national production and daily life, such as in hotels, restaurants, food processing, textiles, chemicals, and feed processing industries.

[0003] However, most of the existing inspection-exempt once-through gas-fired steam generators on the market have excessive actual water volume. Especially after the promulgation and implementation of the 2020 version of the boiler code, the calculation method for water volume was clarified, namely, the total geometric volume inside the steam-water system inlet and outlet, which includes the entire pressurized space from the feedwater pump outlet to the equipment's steam outlet. Based on this calculation method, the water volume of most once-through gas-fired steam generators on the market far exceeds 30 liters. This not only fails to meet the boiler code's inspection-exempt standard, but also poses a significant safety hazard because the condenser installed inside the equipment, as a pressure-bearing component, has high pressure requirements.

[0004] To address the aforementioned issues and reduce the water volume of the steam generator, Rejing Energy Saving Technology has filed an invention patent application (publication number CN114508745A) for a novel once-through steam generator or steam boiler and its heat exchange unit. This patent employs a single-ring riser structure in conjunction with a burner to achieve a small-volume steam generator structure. Furthermore, Rejing Energy Saving Technology has filed an invention patent application (publication number CN115614722A) for a steam generating device and its operating method. This invention patent also employs a dual-pump operating system in conjunction with a buffer to solve the cavitation problem.

[0005] Although the small-volume steam generator disclosed in the above patent can solve the technical problem of producing sufficient high-quality steam under small volume conditions, it still cannot achieve the same service life as traditional water tube boilers in actual use. Long-term continuous operation at high temperature and high pressure can easily cause dry burning damage to the upper part of the heat exchanger.

[0006] Further research revealed that in small-capacity once-through steam boilers (steam generators), the vertical heat exchange unit is directly surrounding the burner. A steam-water interface exists inside the vertical heat exchange tubes. Due to the large overlap between the burner and the heat exchange tubes required for small-capacity operation, the steam-water interface cannot be higher than the burner's fire boundary. This results in a certain length of steam section of the heat exchange tube being exposed inside the combustion chamber, directly corresponding to the burner's combustion zone. However, the specific heat capacity of steam is much lower than that of water, leading to weak heat absorption in the steam section. This results in continuous dry burning, causing damage to the heat exchange tubes and reducing the lifespan of the steam generator. Summary of the Invention

[0007] In view of the above problems, one object of this disclosure is to provide a steam generating device that can avoid damage to heat exchange tubes by dry burning.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A steam generating apparatus, comprising:

[0010] Burner;

[0011] A first heat exchange assembly is provided with a combustion chamber for combustion in the burner, defining a first flue gas flow channel and a main heat exchange flow channel; the water in the main heat exchange flow channel exchanges heat with the flue gas in the first flue gas flow channel, partially vaporizes, and outputs a steam-water mixture with a temperature above 90°C.

[0012] A second heat exchange assembly is defined by a second flue gas flow channel and a steam generation flow channel; the second flue gas flow channel is connected downstream of the first flue gas flow channel in the flue gas flow direction, and the steam generation flow channel is connected downstream of the main heat exchange channel in the water flow direction; the steam-water mixture in the steam generation flow channel exchanges heat with the flue gas in the second flue gas flow channel to form steam; the second heat exchange assembly has a steam output end for outputting steam.

[0013] In a preferred embodiment, the second heat exchange component is equipped with a boiler water level gauge.

[0014] In a preferred embodiment, a third heat exchange component is also provided; the third heat exchange component defines a third flue gas flow channel and a preheating flow channel; the third flue gas flow channel is connected downstream of the second flue gas flow channel in the flue gas flow direction; the preheating flow channel is connected upstream of the main heat exchange channel in the water flow direction; the water in the preheating flow channel exchanges heat with the flue gas in the third flue gas flow channel to preheat it.

[0015] In a preferred embodiment, the third heat exchange component is a condensing heat exchanger, which has a first water inlet and a first water outlet; a first water pump is connected upstream of the first water inlet.

[0016] The first heat exchange component has a second water inlet and a second water outlet; a second water pump is connected in series between the first water outlet and the second water inlet; the head of the second water pump is greater than the head of the first water pump; the head of the first water pump is greater than the water resistance of the third heat exchange component.

[0017] In a preferred embodiment, the first heat exchange assembly includes a cylindrical shell and a first heat exchange unit inside the cylindrical shell; the first heat exchange unit is connected between a second water inlet and a second water outlet; the first heat exchange unit defines a plurality of first vertical heat exchange tubes of the main heat exchange channel, the first vertical heat exchange tubes surrounding the combustion chamber of the burner.

[0018] In a preferred embodiment, the first heat exchange assembly further includes an inner rod inside at least one of the first vertical heat exchange tubes; a water storage space is formed between the outer wall of the inner rod and the inner wall of the heat exchange tube; and the length of the inner rod along the length of the heat exchange tube is more than 20% of the length of the heat exchange tube.

[0019] In a preferred embodiment, the second heat exchange assembly includes a housing and a second heat exchange unit located within the housing; the second heat exchange unit includes a plurality of second vertical heat exchange tubes defining the steam generation channel; the second heat exchange assembly has a third water inlet communicating with a second water outlet; the third water inlet is located at the lower end of the second heat exchange unit.

[0020] In a preferred embodiment, the upper end of the second heat exchange component is provided with an upper header box connected to the steam output end, and the lower end of the second heat exchange component is provided with a lower header box connected to the third water inlet end; the upper ends of the plurality of second vertical heat exchange tubes are connected to the upper header box, and the lower ends are connected to the lower header box.

[0021] In a preferred embodiment, the second heat exchange assembly has a steam-water separation component disposed inside the at least one second vertical heat exchange tube at a position of more than 50% of the height of the second vertical heat exchange tube; the steam-water separation component is configured to form a blockage of at least a portion of the steam-water fluid flowing along the length direction of the heat exchange tube, and has a fluid flow path with fluid output at the upper end and fluid input at the lower end; the length of the steam-water separation component along the length direction of the heat exchange tube is more than 1% and less than 30% of the length of the heat exchange tube, or the length along the length direction of the heat exchange tube is 5mm-500mm.

[0022] In a preferred embodiment, the main heat exchange channel surrounds the combustion chamber; the steam generation channel is located outside the first heat exchange assembly.

[0023] Beneficial effects

[0024] One embodiment of the steam generating device of this application adds a second heat exchange component between the condenser heat exchanger and the first heat exchange component (steam generating body). The second heat exchange component exchanges heat with the flue gas flow to form secondary vaporization, and also provides a steam-water separation site. Compared with the first heat exchange component, the second heat exchange component is further away from the high-temperature flame, and the steam section of its heat exchange tube is far away from the high-temperature flame, avoiding high-temperature dry burning, thus ensuring both steam quality and service life.

[0025] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0026] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a perspective structural diagram of a steam generating apparatus according to an embodiment of the present disclosure;

[0029] Figure 2 This is a perspective structural diagram of a steam generating apparatus according to an embodiment of the present disclosure;

[0030] Figure 3 yes Figure 2 Another view;

[0031] Figure 4 yes Figure 2 The front view;

[0032] Figure 5 yes Figure 2 3D structural diagram of the second heat exchange component;

[0033] Figure 6 yes Figure 5 Another view;

[0034] Figure 7 yes Figure 5 A schematic diagram of the second vertical heat exchange tube arrangement;

[0035] Figure 8This is a perspective structural diagram of a steam generating apparatus according to another embodiment of the present disclosure. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0037] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] One embodiment of this disclosure provides a steam generating device, which is applicable to, but not limited to, inspection-free steam generators or steam boilers. Preferably, the water volume of the steam generating device is less than 50L, and more preferably, the water volume of the steam generating device is less than 30L.

[0040] Please see Figure 1 The steam generating device in this embodiment includes a burner, a first heat exchange component 50, a second heat exchange component 70, a first water pump 10, and a second water pump 40. The first heat exchange component 50 defines a first flue gas flow channel and a main heat exchange flow channel. Water in the main heat exchange flow channel exchanges heat with the flue gas in the first flue gas flow channel, forming a steam-water mixture within the main heat exchange flow channel. The steam-water mixture is output from the main heat exchange flow channel at a temperature of 90 degrees Celsius or higher. The steam-water mixture contains at least 15% (liquid phase) water; for example, the steam-water mixture output from the first heat exchange component 50 contains at least 40% liquid water, thus more than half the weight of water is heated and vaporized in the first heat exchange component 50. Furthermore, the steam-water mixture contains at least 50% (liquid phase) water vapor.

[0041] The second heat exchange assembly 70 defines a second flue gas flow channel and a steam generation flow channel. The second flue gas flow channel is connected downstream of the first flue gas flow channel in the flue gas flow direction. The steam generation flow channel is connected downstream of the main heat exchange channel in the water flow direction. The water (steam-water mixture) in the steam generation flow channel exchanges heat with the flue gas in the second flue gas flow channel to form steam. The second heat exchange assembly 70 has a steam output end 71 for outputting steam. Nearly all the remaining water in the steam-water mixture is heated and vaporized in the steam generation flow channel, thus the steam output by the second heat exchange assembly (steam output end 71) has a dryness fraction of 90% or more. Preferably, the steam output by the steam output end 71 has a dryness fraction of 98% or more.

[0042] The water volume of the steam generator in this embodiment can be less than 50 liters, the steam dryness can reach more than 95% (up to 98%), the evaporation capacity can reach 1000 kg / h, and the energy saving effect is more than 30% higher than that of traditional boilers.

[0043] The first heat exchange assembly 50 defines a combustion chamber where a burner burns to form a high-temperature flame and outputs high-temperature flue gas. A main heat exchange channel surrounds the combustion chamber, with a first vertical heat exchange tube serving as its carrier. The combustion space surrounding the main heat exchange channel constitutes the combustion chamber, and the burner is a cylindrical burner that extends into the combustion chamber. The steam generation channel is located outside the first heat exchange assembly 50, away from the high-temperature flame.

[0044] The steam generating equipment also includes a third heat exchange assembly 20. The third heat exchange assembly 20 defines a third flue gas flow channel (flue gas flow space) and a preheating channel (water flow space). The third flue gas flow channel is connected downstream of the second flue gas flow channel in the flue gas flow direction. The water in the preheating channel exchanges heat with the flue gas in the third flue gas flow channel to preheat it. The preheated water output by the third heat exchange assembly 20 has a temperature above 60°C. The preheating channel is connected upstream of the main heat exchange channel in the water flow direction. The preheating channel has a first inlet end and a first outlet end. In this embodiment, the first, second, and third inlet ends and the first and second outlet ends are constructed with flange connections.

[0045] The steam heat exchanger in this embodiment employs a dual-pump relay heat exchange system. The energy-saving device (third heat exchange component 20) is not pressurized, improving the safety factor and extending its service life. The third heat exchange component 20 is a condensing heat exchanger, having a first inlet and a first outlet. A first water pump 10 is connected upstream of the first inlet. The first heat exchange component 50 has a second inlet 52 and a second outlet 53. A second water pump 40 is connected in series between the first outlet and the second inlet 52. The head of the second water pump 40 is greater than the head of the first water pump 10; the head of the first water pump 10 is greater than the water resistance of the third heat exchange component 20.

[0046] The steam generating equipment in this embodiment is equipped with dual pump operation. The first water pump 10, located before the third heat exchange component 20, cancels the water resistance of the third heat exchange component 20. The second water pump 40, located downstream of the third heat exchange component 20 (along the water flow direction), is also canceled by the first water pump 10 due to the water resistance (pipeline resistance) of the third heat exchange component 20. As a result, the impact of the third heat exchange component 20 on the pumping efficiency of the second water pump 40 is small or even eliminated. Thus, under the action of the dual pumps, water can be supplied to the first heat exchange component 50 (furnace body) in a timely manner, meeting the water level control requirements of the first heat exchange component 50.

[0047] Furthermore, the third heat exchange component 20 is located upstream of the second water pump 40 and does not require a pressurized design. Consequently, the third heat exchange component 20 (energy saver) is not a pressurized device, which can better improve the pressurized water volume. This ensures that the internal geometric volume of the steam generating equipment from the outlet of the second water pump 40 to the steam output end 71 of the second heat exchange component 70 is less than 30L. This achieves true safety without inspection and avoids affecting the steam generation speed and evaporation rate of the steam generator or steam boiler.

[0048] To avoid increasing the water volume, the water in the main heat exchange channel of the first heat exchange component 50 undergoes a phase change to form water vapor, creating a steam-water mixture within the first heat exchange component 50. Part of the water in the first heat exchange component 50 vaporizes through heat exchange with the high-temperature flue gas, while some liquid water falls faster than the water vapor due to gravity, thus avoiding separation from the descending water vapor and forming the steam-water mixture. The steam-water mixture is output from the second outlet 53 of the first heat exchange component 50.

[0049] To prevent steam-water separation and dry burning in the first heat exchange component 50, the second water inlet 52 of the first heat exchange component 50 is higher than the second water outlet 53. Further, the second water inlet 52 is located at the upper end of the first heat exchange component 50, and the second water outlet 53 is located at the lower end of the first heat exchange component, and is connected to the third water inlet 73 via a pipe 68. Alternatively, as... Figure 8 In the embodiment shown, the second water outlet 53 is located at the upper end of the first heat exchange component 50 and is connected to the third water inlet 73 through the pipe 68'. At this time, the second water inlet 52 of the first heat exchange component 50 is located at its lower end.

[0050] The second heat exchange component 70 is connected downstream of the first heat exchange component 50. It is directly fed by the steam-water mixture formed by the first heat exchange component 50. This can also prevent the second heat exchange component 70 from becoming a steam superheater, which would not meet the demand for saturated steam. At the same time, it would cause the heat absorption capacity of the second heat exchange component 70 to decrease, resulting in overheating problems and affecting its service life.

[0051] In this embodiment, the second heat exchange component 70 exchanges heat with the flue gas flow to form secondary vaporization, and also provides a steam-water separation site. Compared with the first heat exchange component 50, the second heat exchange component 70 is further away from the high-temperature flame, and the steam section of its heat exchange tube is far away from the high-temperature flame, avoiding dry burning, thus ensuring both steam quality and service life.

[0052] The steam generator in this embodiment includes a second heat exchange component 70, which can keep the steam-water interface away from the flame (high-temperature flame) and prevent the water volume from increasing, thereby avoiding dry burning and damage to the heat exchange tubes. It is conceivable that this steam generator structure can still be applied to large-capacity steam generators to avoid dry burning problems.

[0053] In this embodiment, the steam generating device is a cross-flow steam generator. The first heat exchange assembly 50 includes a cylindrical shell and a first heat exchange unit inside the cylindrical shell. The first heat exchange unit is connected between the second water inlet 52 and the second water outlet 53. The first heat exchange unit includes a plurality of parallel-arranged first vertical heat exchange tubes defining the main heat exchange channel. The first heat exchange assembly 50 serves as the main heat exchanger, providing the main heat exchange site for steam generation. To ensure that the incoming water absorbs heat and partially vaporizes in the first heat exchange assembly 50, the length of the first vertical heat exchange tube is greater than the length of the second vertical heat exchange tube 711. The lower end of the first vertical heat exchange tube is located below the second vertical heat exchange tube 711, and the upper end of the first vertical heat exchange tube is higher than the upper end of the second vertical heat exchange tube 711. A flow-blocking structure may also be provided inside the first vertical heat exchange tube to prevent excessive flow velocity and improve heat exchange efficiency. The flow-blocking structure can be a flow-blocking baffle inside the first vertical heat exchange tube, which can also mix steam and water to prevent steam-water separation.

[0054] To prevent the water volume from exceeding 30 liters, an inner rod is installed inside the first vertical heat exchange tube. This inner rod can be a solid rod structure or a blind tube structure (sealed tube) that is not connected to the internal parts of the first vertical heat exchange tube. The inner rod reduces the water storage volume within the first vertical heat exchange tube. The inner rod is a sealed tube with its upper and lower ends sealed by upper and lower sealing plates, coaxially arranged inside the first vertical heat exchange tube. Alternatively, the inner rod can be radially eccentrically positioned outwards, allowing more water to remain on the inner side for more efficient heat exchange.

[0055] In this embodiment, a water storage space (water storage annulus) is formed between the outer wall of the inner rod and the inner wall of the first vertical heat exchange tube. The length of the inner rod along the length direction of the first vertical heat exchange tube (hereinafter referred to as the axial length) (the length of the inner rod within the first vertical heat exchange tube) is more than 20% of the length of the heat exchange tube, and further, the length of the inner rod is more than 80% of the length of the heat exchange tube.

[0056] Compared to the single main heat exchanger equipment of existing steam generators, this embodiment focuses more on the gas-liquid mixed fluid state output by the first heat exchange unit. Thus, unlike the existing technology that avoids liquid level instability due to the inner rod occupying too much space inside the tube, the length of the inner rod in this embodiment can be more than 50% of the length of the first vertical heat exchange tube, or even more than 80% of the length of the first vertical heat exchange tube.

[0057] In one feasible embodiment, for example, the inner rod extends from the lower end to the upper end of the first vertical heat exchange tube, constructing a water storage annulus of equal length inside the first vertical heat exchange tube to minimize the water volume under the dual-pressure heat exchanger. The presence of the inner rod reduces the evaporation space inside the first vertical heat exchange tube, preventing excessive water evaporation. Furthermore, the unstable agitation of the water facilitates mixing with vaporized water vapor, forming the desired steam-water mixture. This shifts the primary evaporation site to the second heat exchange assembly 70, where a steam-water separation interface (observable by a boiler water level gauge) is formed.

[0058] Water in the first heat exchange component 50 forms water vapor. The water vapor does not separate from the water phase, forming a mixed steam-water mixture with a high steam content or a water-containing steam mixture with a high water content. Consequently, no obvious steam-water interface is formed inside the first vertical heat exchange tube of the first heat exchange component 50, which can be monitored by the connected water level gauge 59.

[0059] In this embodiment, the second heat exchange assembly 70 includes a housing 700 and a second heat exchange unit 710 located within the housing; the second heat exchange unit 710 includes a plurality of parallel-arranged second vertical heat exchange tubes 711 defining the steam generation flow channel. The second vertical heat exchange tubes 711 have a straight tube structure. The third heat exchange assembly 20 has a third water inlet end 73; the third water inlet end 73 is connected to the lower end of the second heat exchange unit 710. The second heat exchange assembly 70 is located between the first heat exchange assembly 50 and the third heat exchange assembly 20. Preferably, the second vertical heat exchange tubes 711 can also be finned heat exchange tubes to improve heat exchange efficiency.

[0060] The second heat exchange component 70 is equipped with a boiler water level gauge 79. As an optional embodiment, such as... Figure 2 , Figure 3 As shown, the first heat exchange component 50 is equipped with a boiler level gauge 79. The boiler level gauge 79 and the boiler level gauge 59 can be the liquid level measuring device disclosed in publication number CN218846111U of Anhui Rejing Boiler Co., Ltd., which will not be elaborated here. The boiler level gauge 79 is used to monitor the water level of the second heat exchange component 70, preventing the steam-water interface of the second heat exchange component 70 from being too high or too low, thereby ensuring the steam quality of the second heat exchange component 70.

[0061] As can be observed by the boiler water level gauge 79, the liquid level (steam-water interface) of the second heat exchange component 70 is between 20%-30% and 90% of the height of the second vertical heat exchange tube. That is, the liquid level in the second vertical heat exchange tube is at least 20%-30% of the tube height and at most around 90%. Preferably, the liquid level in the second vertical heat exchange tube is between 40% and 70% of the tube height to provide sufficient vaporization and steam-water separation space, thereby improving the quality of the output steam.

[0062] like Figure 5 , Figure 6 As shown, the second heat exchange assembly 70 has an upper header 77 at its upper end and a lower header 76 at its lower end. The upper ends of the plurality of second vertical heat exchange tubes 711 are connected to the upper header 77, and the lower ends are connected to the lower header 76. The third water inlet 73 is connected to the lower header 76, and the steam outlet 71 is connected to the upper header 77. The upper header 77 has an upper connecting space, through which the plurality of second vertical heat exchange tubes 711 simultaneously enter the upper header 77, and simultaneously input steam into the upper header 77. The lower header 76 has a lower connecting space, through which the steam-water mixture discharged from the first heat exchange assembly 50 is introduced, and simultaneously input into the plurality of second vertical heat exchange tubes 711.

[0063] In this embodiment, the second heat exchange assembly 70 is equipped with a steam-water separation component to separate steam and water, thereby improving steam dryness. The steam-water separation component can be installed in the upper header 77 and adopt a structure such as an orifice plate. Alternatively, the steam-water separation component can be installed in the second vertical heat exchange tube 711 and adopt a structure such as a spiral plate. When the steam-water separation component is located in the second vertical heat exchange tube 711, it is positioned above the steam-water interface and close to the upper end of the second vertical heat exchange tube 711.

[0064] Specifically, the second heat exchange assembly 70 has a steam-water separation component disposed inside the at least one second vertical heat exchange tube 711 at a position above 50% of the height of the second vertical heat exchange tube. The steam-water separation component forms at least an axial obstruction to at least a portion of the steam-water fluid, increasing the radial (horizontal) component of the movement direction of this portion of the steam-water fluid and decreasing the axial component of the movement direction. Furthermore, when the liquid water in the steam-water fluid comes into contact with the steam-water separation component, it will condense and separate from the water vapor.

[0065] Preferably, more than half, or even all, of the second vertical heat exchange tubes 711 are equipped with steam-water separation components, which are disposed inside the second vertical heat exchange tubes 711, thus eliminating the need for a drain pipe. More preferably, the second heat exchange components 70 are located at a position above 70% of the height of the second vertical heat exchange tubes. The steam-water separation components are configured to form a barrier against at least a portion of the steam-water fluid flowing along the length of the second vertical heat exchange tubes 711, and have a fluid flow path with fluid output at the upper end and fluid input at the lower end. The length of the steam-water separation components along the length of the second vertical heat exchange tubes is more than 1% and less than 30% of the length of the second vertical heat exchange tubes 711, or the length along the length of the second vertical heat exchange tubes 711 is 5mm-500mm.

[0066] An illustrative example is provided: a steam-water separation assembly includes a support core rod and a spiral plate. A second vertical heat exchange tube 711 is sleeved on the support core rod. The spiral plate extends spirally along the length of the second vertical heat exchange tube 711 between the support core rod and the second vertical heat exchange tube 711. The spiral plate is connected to the outer wall of the support core rod and / or the inner wall of the second vertical heat exchange tube 711. A boiling stop plate is provided at the lower end of the support core rod and / or a steam outlet plate is provided at the upper end of the support core rod. The spiral plate extends spirally between the boiling stop plate and the steam outlet plate. The boiling stop plate has an inlet hole for fluid to enter the fluid flow path. The steam outlet plate has an outlet hole for fluid to exit. The outlet hole and the inlet hole axially penetrate the steam outlet plate and the boiling stop plate, respectively. Their shapes can be circular holes, rectangular holes, triangular holes, elongated holes, or other regular or irregular shapes. This disclosure does not impose any particular limitation.

[0067] Furthermore, to improve gas-liquid separation and anti-boiling effects, the total area of ​​the inlet holes of the anti-boiling plate is less than the total area of ​​the outlet holes of the steam outlet plate. The total area of ​​the inlet holes accounts for more than 3% and less than 50% of the internal cross-sectional area of ​​the second vertical heat exchange tube 711, and more specifically, more than 5% and less than 30%.

[0068] In this embodiment, the steam-water separation component performs initial separation of the steam and water fluids within the second vertical heat exchange tube, removing a large amount of water from the steam and water fluids and increasing the steam dryness. The steam-water separation component is located at the upper end inside the second vertical heat exchange tube, maintaining separation from the liquid phase water stored inside the second vertical heat exchange tube, and sufficient evaporation space is provided between the two to ensure that the liquid phase water can fully evaporate to form steam, which is then separated by the steam-water separation component.

[0069] In this embodiment, the level gauge of the steam generator is installed in the evaporative heat exchanger (second heat exchange component 70), and the evaporative heat exchanger has a built-in steam-water separation component such as an orifice plate or a spiral separation component, thereby improving the steam quality.

[0070] Continuing from the above description, the first water pump 10 is connected upstream of the first water inlet. Water is input from an external source to the inlet of the first water pump 10, which can be connected to an inlet container. The inlet container can be provided by an external water tank, a water tower, or a water tank; this disclosure does not impose any limitations. The head of the first water pump 10 is configured to be greater than the water resistance of the third heat exchange component. The second water pump 40 is connected between the first water outlet and the second water inlet, and the head of the second water pump 40 is greater than the head of the first water pump 10. For example, the head of the first water pump 10 is greater than 5m and less than 9m, and the head of the second water pump 40 is greater than 80m, thereby ensuring water replenishment efficiency and steam output efficiency.

[0071] The first water pump 10, the condenser heat exchanger (a specific embodiment of the third heat exchange component 20), the second water pump 40, the first heat exchange component 50, and the second heat exchange component 70 (evaporator heat exchanger) are connected in series in sequence. Water flows sequentially through the first water pump 10, the third heat exchange component 20, and the second water pump 40 into the first heat exchange component 50 and the second heat exchange component 70.

[0072] In this embodiment, the internal geometric volume (water volume) of the steam generating device from the outlet of the second water pump 40 to the steam output of the first heat exchange component 50 is less than 50L, and more preferably, the water volume of the steam generating device is less than 30L. To reduce the water volume, both the first heat exchange component 50 and the second heat exchange component 70 are riser heat exchange structures, and no other heat exchanger structure is provided between them. The second heat exchange component 70 is directly connected to the downstream of the first heat exchange component 50, and no other intermediate heat exchange mechanism is provided between them.

[0073] The first water pump 10 is a fixed-frequency pump, and the second water pump 40 is a variable-frequency pump. Specifically, the second water pump 40 can be a multi-stage centrifugal variable-frequency pump to provide a larger head and form a pressurized water circuit downstream of it. For example, the first water pump 10 is a 6m head fixed-frequency pump, and the second water pump 40 is a 150m head booster pump (variable-frequency pump). The upstream water circuit of the second water pump 40 is an atmospheric pressure pipeline (non-pressurized pipeline), and the downstream water circuit is a pressurized pipeline.

[0074] The heat exchange unit of the first heat exchange assembly 50 consists of multiple first vertical heat exchange tubes arranged in a single loop along the circumference. A main heat exchange channel is formed inside each first vertical heat exchange tube, and a first flue gas flow channel is formed on its outside. The first flue gas flow channel is connected to the flue gas outlet 55. The first heat exchange assembly 50 has only a single loop of vertical heat exchange tubes to reduce water volume. The flue gas outlet 55 includes a flue gas outlet port formed on the side wall of the cylindrical shell of the first heat exchange assembly 50. Correspondingly, a flue gas inlet port 74, which is connected to the flue gas outlet port 55, is formed on one side of the shell 700 of the second heat exchange assembly 70.

[0075] In this embodiment, the first heat exchange unit of the first heat exchange assembly 50 is an annular vertical tube structure, and the second heat exchange unit 710 of the second heat exchange assembly 70 is a staggered vertical tube structure. The second vertical heat exchange tubes 711 in the second heat exchange assembly 70 are arranged in a staggered manner to increase the flue gas flow path and flue gas resistance, thereby improving heat exchange efficiency.

[0076] like Figure 7 The diagram shown is a top view of the heat exchange tube arrangement, along the direction from the flue gas inlet to the flue gas outlet. Figure 7 The second vertical heat exchange tubes 711 are arranged in a crisscross pattern, forming multiple rows, meaning the second heat exchange assembly 70 has multiple rows of heat exchange tubes 750. Each row of heat exchange tubes (each row of heat exchange tubes 750) is perpendicular to the overall flue gas flow direction. A flow gap 712 exists between adjacent second vertical heat exchange tubes 711. Specifically, in two rows of heat exchange tubes 750, the heat exchange tubes 711 of one row of heat exchange tubes 750 are directly opposite the flow gap 712 between the two heat exchange tubes 711 of the other row of heat exchange tubes 750 along the overall flue gas flow direction.

[0077] In this embodiment, the steam generating section is located at the evaporative heat exchanger where the flue gas temperature is relatively low. The flue gas passes through the first heat exchange component 50, preventing the working fluid from forming a distinct steam-water interface in the high-temperature flue gas zone, which would cause the pipe wall temperature to rise and affect the heat exchanger's lifespan. Furthermore, this embodiment's steam heat exchanger employs a fully premixed combustion system, with a cylindrical burner and a cylindrical through-flow first heat exchange component, resulting in better flame radiation and high-temperature flue gas convection heat exchange effects.

[0078] In another feasible embodiment, the steam generating device is a coil-type steam generator. The heat exchange unit of the first heat exchange component is a single-layer coil structure. The single-layer coil is spirally wound to form a cylindrical heat exchange unit. The steam generating device in this embodiment can also use finned tubes (finned coils) to maximize the heat exchange area, improve thermal efficiency, and increase evaporation rate within a limited water volume. In this embodiment of the coil-type steam generator, the steam-water boundary of the single-layer coil heat exchange unit is not obvious due to its spiral flow channel structure, thus allowing direct output of a steam-water mixture. Therefore, the second water inlet of the first heat exchange component can be located at the upper end of the first heat exchange component, and the second water outlet at the lower end of the first heat exchange component; or, the second water inlet of the first heat exchange component can be located at the lower end of the first heat exchange component, and the second water outlet at the upper end of the first heat exchange component.

[0079] Following the description above, one end of the burner ( Figure 1 , Figure 2 , Figure 3The upper part of the burner (located in the middle) is connected to a fan 60, which is connected to a gas valve. The fan 60 has a gas inlet and an air inlet; the air inlet is connected to a filter, and the gas inlet is connected to the gas valve. The first heat exchange assembly 50 also includes an ignition component such as an ignition needle for igniting the burner and a flame detector such as a flame probe for sensing the burner flame. The ignition component and the flame detector are fixedly mounted on the base plate of the combustion chamber.

[0080] When the second water pump 40 is connected downstream of the third heat exchange component 20, the third heat exchange component 20 preheats the cold water. The preheated water temperature can reach 70 or 80 degrees Celsius or higher. This causes gas to be released or even vaporized in the water, producing a large amount of gas that flows together. Studies have found that the gas easily accumulates at the second water pump 40, forming gas bubbles and gas clusters. This not only causes cavitation problems, affecting the pump's service life, but also reduces the pump efficiency of the second water pump 40, making it impossible to supply water to the furnace body in a timely manner, resulting in unstable liquid levels in the furnace body and unstable steam production. Although an exhaust valve (such as a normally closed exhaust valve) can be integrated into the second water pump 40, exhaust is still not timely when a large amount of gas is generated.

[0081] To avoid the aforementioned problems, in this embodiment, a buffer container 30 with an internal water-holding space is connected between the water inlet of the third heat exchange component 20 and the water inlet of the second water pump 40. Warm water enters the water-holding space and flows slowly, while gas is released, preventing it from entering the second water pump 40. The buffer container 30 also has a communication structure that connects the water-holding space to the outside when the water level inside is at least below a preset level. This communication structure has an venting function and can therefore be called an venting structure. The water-holding space provides a space to contain water that has exchanged heat with flue gas or after heat exchange; correspondingly, the released gas is released by accumulating in the water-holding space. Furthermore, the existence of the communication structure ensures that a gas release and accumulation space exists above the liquid surface when a certain water level is not reached (e.g., the water is not full), thus achieving gas discharge. Both the buffer container 30 and the third heat exchange component are connected downstream of the first water pump 10, and the pressure head of the first water pump 10 is less than 1 Bar, therefore neither the third heat exchange component nor the buffer container 30 is pressurized.

[0082] Even better, this connection structure remains open to the outside when the water level is low, so there is no need to open the pressure to release the gas. The gas can escape outward as soon as it is released. Therefore, even if it is applied to a scenario with a large amount of gas release, there will still be no problem of gas entering the second water pump 40 and causing it to run dry or making it difficult to replenish water.

[0083] In this embodiment, the buffer container 30 is connected upstream of the second water pump 40 and downstream of the third heat exchange component, that is, the buffer container 30 is connected between the water inlet of the second water pump 40 and the water inlet of the third heat exchange component. The connecting structure is connected to the external atmosphere at least when the water level inside the water-containing space is lower than a preset water level. The preset water level can be above 70% of the water-containing space, or it can be 100% of the water level; that is, when the space is full of water, the connecting structure is closed, forming a closed water-containing space. As the second water pump 40 draws in water and gas is released, the pressure inside the water-containing space increases, and the water level in the water-containing space gradually decreases until the connecting structure (automatic air vent) reopens.

[0084] In this embodiment, the buffer container 30 is a tank structure that stores warm water that has exchanged heat with or after heat exchange with the flue gas. To prevent heat loss, insulation measures are provided on the outside of the buffer container 30. The volume of the buffer container 30 is between 1L and 500L, and more specifically, between 20L and 50L. The communication structure is configured to connect with the atmosphere when the water level is below a predetermined level and disconnect from the atmosphere when the water level is above the predetermined level.

[0085] Understandably, when the buffer container 30 is in a waterless or low-water state, the connecting structure is open. During the process of water being introduced into it, the connecting structure remains open, allowing gas to escape without pressure. This reduces the amount of gas in the water entering the second water pump 40 and eliminates the potential risk of the second water pump 40 running dry and unable to replenish water.

[0086] Specifically, the communication structure is a normally open exhaust valve 35 (e.g., a normally open automatic exhaust valve) located at the upper end of the buffer container 30. The communication structure is situated at a height of at least 70% of the internal bottom surface of the buffer container 30. Figure 2 , Figure 4 As shown, the vent valve 35 is installed on the top of the buffer container 30. The vent valve 35 may be equipped with a float that is linked to the sealing valve core. When the liquid level rises to a predetermined level (water level), the float rises, causing the sealing valve core to close the vent valve 35, thereby preventing water from overflowing from the buffer container 30. The second water pump 40 is connected to the buffer container 30, and the water in the buffer container 30 is pumped by the second water pump 40, which also avoids the risk of cavitation caused by the second water pump 40 running dry due to a large air volume. Of course, to avoid leakage due to excessive water intake, the connection structure preferably adopts a normally open automatic vent valve 35.

[0087] like Figure 2 , Figure 3As shown, the third heat exchange component 20 is a condensing heat exchanger that recovers waste heat from the flue gas output end of the first heat exchange component 50. The first fluid flow channel includes the internal flow channel of the condensing heat exchange tubes within the condensing heat exchanger. The second flue gas flow channel is confined within the condensing heat exchanger shell and located between the condensing heat exchange tubes and the condensing heat exchanger shell. The condensing heat exchanger is connected to a first water pump 10 that drives the fluid flow. The first water pump 10 is connected in series between the water inlet connector (equipment water inlet end) and the water inlet end (first water inlet end) of the first fluid flow channel. The condensing heat exchanger shell 21 has a flue gas inlet 23 (flue gas input end), which communicates with the flue gas output end 72 of the second heat exchange component 70. The top of the condensing heat exchanger shell 21 has a flue gas outlet 28 (flue gas output end). The condensing heat exchanger has a first water inlet end and a first water outlet end, and multiple condensing heat exchange tubes connected in series or parallel are defined between the first water inlet end and the first water outlet end. The first water inlet and the first water pump 10 are connected by a first pipe. The water inlet of the first water pump 10 is connected to the water inlet connector to input external cold water.

[0088] In this embodiment, the buffer container 30 is a buffer water storage tank connected upstream of the second water pump 40 and downstream of the third heat exchange component 10. The height of the buffer water storage tank is lower than the height of the condensing heat exchanger, and the buffer water storage tank is located below the condensing heat exchanger. The height of the buffer water storage tank is more than 0.2m and less than 1.5m; the cross-sectional area of ​​the water-containing space of the buffer water storage tank is more than 100 square centimeters. For example, the water-containing space of the buffer container 30 is a cylindrical cavity with a diameter between 100-300mm and a height of about 500mm (±100mm).

[0089] The inlet of the second water pump 40 is connected to the outlet of the buffer water tank via a pipe. The inlet of the buffer water tank is connected to the first outlet of the third heat exchange component via pipe 25. The outlet of the second water pump 40 is connected to the second inlet 52 of the first heat exchange component 50 via pipe 45. The second inlet 52 is located at the upper end of the first heat exchange component 50. The second outlet 53 is located at the lower end of the first heat exchange component 50. The flue gas outlet 55 is located on the side wall of the first heat exchange component 50, forming a flue gas outlet, and is fixedly connected to the flue gas inlet 74 of the second heat exchange component 70 via a flange. A drain pipe 54 is also provided at the bottom of the lower header of the first heat exchange component 50.

[0090] It should be noted that the construction of the first heat exchange component 50, buffer container 30, first water pump 10, second water pump 40, and third heat exchange component 20 can also be referred to the description in the Chinese patent application filed by the applicant on October 15, 2022, with publication number CN115614722A and invention title "Steam Generating Equipment and Operating Method Thereof". The repeated parts will not be repeated.

[0091] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or process variable (e.g., temperature, pressure, time, etc.) is described as ranging from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30, etc., are also explicitly listed in this specification. For values ​​less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of numerical values ​​listed between the minimum and maximum values ​​are explicitly described in this specification in a similar manner.

[0092] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0093] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0094] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0095] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A steam generating device, wherein, The steam generating equipment is a once-through steam generator; the steam generating equipment includes: Burner; A first heat exchange assembly is provided with a combustion chamber for combustion in the burner, defining a first flue gas flow channel and a main heat exchange channel; water in the main heat exchange channel vaporizes with the flue gas in the first flue gas flow channel, and outputs a steam-water mixture with a temperature above 90°C; the first heat exchange assembly includes a cylindrical shell and a first heat exchange unit inside the cylindrical shell; the first heat exchange unit defines multiple parallel first vertical heat exchange tubes in the main heat exchange channel, the first vertical heat exchange tubes surrounding the combustion chamber of the burner; the first heat exchange assembly has a second water inlet and a second water outlet; the second water inlet of the first heat exchange assembly is higher than the second water outlet; the first heat exchange unit connects the second water inlet and the second water outlet. A second heat exchange assembly is defined by a second flue gas flow channel and a steam generation flow channel; the second flue gas flow channel is connected downstream of the first flue gas flow channel in the flue gas flow direction, and the steam generation flow channel is connected downstream of the main heat exchange channel in the water flow direction; the steam-water mixture in the steam generation flow channel exchanges heat with the flue gas in the second flue gas flow channel to form steam; the second heat exchange assembly has a steam output end for outputting steam.

2. The steam generating equipment as described in claim 1, wherein, The second heat exchange component is equipped with a boiler water level gauge.

3. The steam generating equipment as described in claim 1, wherein, A third heat exchange component is also provided; the third heat exchange component defines a third flue gas flow channel and a preheating flow channel; the third flue gas flow channel is connected downstream of the second flue gas flow channel in the flue gas flow direction; the preheating flow channel is connected upstream of the main heat exchange channel in the water flow direction; the water in the preheating flow channel exchanges heat with the flue gas in the third flue gas flow channel to preheat it.

4. The steam generating equipment as described in claim 3, wherein, The third heat exchange component is a condensing heat exchanger, which has a first water inlet and a first water outlet; a first water pump is connected upstream of the first water inlet. A second water pump is connected in series between the first water outlet and the second water inlet; the head of the second water pump is greater than the head of the first water pump; the head of the first water pump is greater than the water resistance of the third heat exchange component.

5. The steam generating equipment as described in claim 1, wherein, The first heat exchange assembly also has an inner rod inside at least one of the first vertical heat exchange tubes; a water storage space is formed between the outer wall of the inner rod and the inner wall of the heat exchange tube; the length of the inner rod along the length of the heat exchange tube is more than 20% of the length of the heat exchange tube.

6. The steam generating equipment as described in claim 1, wherein, The second heat exchange assembly includes a housing and a second heat exchange unit located within the housing; the second heat exchange unit includes a plurality of second vertical heat exchange tubes defining the steam generation channel; the second heat exchange assembly has a third water inlet connected to a second water outlet; the third water inlet is located at the lower end of the second heat exchange unit.

7. The steam generating equipment as described in claim 6, wherein, The second heat exchange component has an upper header connected to the steam output end at its upper end, and a lower header connected to the third water inlet end at its lower end; the upper ends of the plurality of second vertical heat exchange tubes are connected to the upper header, and the lower ends are connected to the lower header.

8. The steam generating equipment as described in claim 7, wherein, The second heat exchange assembly has a steam-water separation component disposed inside the at least one second vertical heat exchange tube at a position of more than 50% of the height of the second vertical heat exchange tube; the steam-water separation component is configured to form a blockage of at least part of the steam-water fluid flowing along the length direction of the heat exchange tube, and has a fluid flow path with fluid output at the upper end and fluid input at the lower end; the length of the steam-water separation component along the length direction of the heat exchange tube is more than 1% and less than 30% of the length of the heat exchange tube, or the length along the length direction of the heat exchange tube is 5mm to 500mm.

9. The steam generating equipment as described in claim 1, wherein, The main heat exchange channel surrounds the combustion chamber; the steam generation channel is located outside the first heat exchange assembly.

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