Steam generating equipment and system thereof

Abstract

The utility model discloses steam generation equipment and a system thereof, and the steam generation equipment comprises a main heat exchange unit which is provided with a first flue gas flow channel and a steam generation flow channel in a limited manner; water in the steam generation flow channel exchanges heat with flue gas in the first flue gas flow channel to form steam; a preheating flow channel is defined in the preheating unit, and the preheating unit is used for heating water in the preheating flow channel; the preheating flow channel is further connected with a check valve and a water feeding pump in series on the upstream of the steam generation flow channel; the check valve and the preheating flow channel are connected between the water feeding pump and the water inlet end of the steam generation flow channel in series. The steam generation equipment and the steam generation system solve the problem that water supply is not timely due to the fact that resistance is generated when the heat exchange unit is located on the upstream.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of steam generation, in particular to a steam generation device and a system thereof. BACKGROUND

[0002] Under the call of national energy conservation and emission reduction, steam generation devices are accelerating the development of full premixing condensing type with high efficiency and low emission. Especially the exempted inspection type tubular gas steam generator, compared with the traditional steam boiler, it has faster steam production speed, is more energy-saving and environmentally friendly, and does not need to install inspection and boiler annual inspection, so it is widely favored by the market and is widely used in national production and life, such as hotels, hotels, food processing, textile, chemical industry, feed processing and other industries.

[0003] However, the exempted inspection type tubular gas steam generator on the market generally has a real water volume exceeding the standard. In the latest “Boiler Safety Technical Regulations”, the calculation method of water volume of small steam boilers is clearly defined, that is, the total geometric volume inside the inlet and outlet of the steam-water pressure-bearing system. Based on this calculation method, the water volume of most small steam boilers on the market far exceeds 30 liters, which not only does not meet the exempted inspection standard, but also the condensing heat exchanger installed in the equipment as a pressure-bearing component has higher pressure-bearing requirements, which poses a certain safety hazard.

[0004] To obtain an exempted inspection steam boiler with a water volume meeting the standard, the applicant applied for a steam generation device with a double-pump relay heat exchange technology disclosed in CN218914889U, but the water inlet of the double-pump relay heat exchange technology is driven by a circulating water pump to flow through the condenser and then enters the buffer water tank, and after deaeration in the buffer water tank, it directly enters the boiler feed water pump. The normal pressure water in the condenser and the water of the boiler pressure-bearing steam-water system are in a direct series communication state. This technical method is very complex for the control of water force balance between the circulating water pump and the main water pump, and for the control of how to avoid overpressure of the condenser. Moreover, there is still some controversy about whether the condenser belongs to the test range of the boiler water volume.

[0005] Therefore, it is very necessary to develop a technology that completely separates the water in the normal pressure condenser from the boiler pressure-bearing steam-water system, and at the same time ensures that the boiler feed water can timely recover the flue gas waste heat to improve the boiler energy efficiency. CONTENT OF THE UTILITY MODEL

[0006] In view of the above research findings, the purpose of the present disclosure is to provide a steam generation device and a system thereof which can effectively improve the energy efficiency and the water volume.

[0007] To achieve the above purpose, the present disclosure adopts the following technical solutions:

[0008] A steam generation device, comprising:

[0009] The main heat exchange unit is defined with a first flue gas flow channel and a steam generation flow channel; water in the steam generation flow channel exchanges heat with flue gas in the first flue gas flow channel to generate steam;

[0010] The preheating unit is defined with a preheating flow channel for heating water in the preheating flow channel; a check valve and a feed water pump are further connected in series upstream of the water inlet end of the steam generation flow channel; the check valve and the preheating flow channel are connected in series between the feed water pump and the water inlet end of the steam generation flow channel.

[0011] Preferably, the feed water pump is connected in series upstream of the water inlet end of the preheating flow channel; the check valve is connected in series upstream of the water inlet end of the steam generation flow channel and downstream of the water outlet end of the preheating flow channel.

[0012] A steam generation device, comprising:

[0013] The main heat exchange unit is defined with a first flue gas flow channel and a steam generation flow channel; water in the steam generation flow channel exchanges heat with flue gas in the first flue gas flow channel to generate steam;

[0014] The preheating unit is defined with a preheating flow channel for heating water in the preheating flow channel; a check valve and a feed water pump are further connected in series upstream of the water inlet end of the steam generation flow channel; the check valve and the preheating flow channel are connected in series between the feed water pump and the water inlet end of the steam generation flow channel.

[0015] As an optional aspect of the utility model, the feed water pump is connected in series upstream of the water inlet end of the preheating flow channel.

[0016] As an optional aspect of the utility model, a secondary heat exchange unit is further provided; the secondary heat exchange unit is defined with a second flue gas flow channel communicated with the downstream of the first flue gas flow channel and a first fluid flow channel; fluid in the first fluid flow channel exchanges heat with flue gas in the second flue gas flow channel to be heated.

[0017] The preheating unit is further defined with a second fluid flow channel communicated with the downstream of the first fluid flow channel; water in the preheating flow channel exchanges heat with fluid in the second fluid flow channel to be heated.

[0018] As an optional aspect of the utility model, the main heat exchange unit comprises a steam generation body with a body water inlet end for inputting water and a flue gas outlet end for outputting flue gas; the steam generation body is provided with vertical heat exchange pipes arranged in a circumferential direction; the inside of the vertical heat exchange pipes forms a steam generation flow channel, and the outside of the vertical heat exchange pipes forms a first flue gas flow channel.

[0019] As an optional aspect of the utility model, the secondary heat exchange unit is a condensation heat exchanger for recovering flue gas waste heat of the flue gas outlet end of the steam generation body; the condensation heat exchanger is further communicated with a circulating water pump for driving fluid flow.

[0020] As an optional aspect of the present application, the steam generating device has a first device water inlet end, and the feed water pump is connected in series between the first device water inlet end and a water inlet end of the preheating flow channel.

[0021] As an optional aspect of the present application, the steam generating device has a second device water inlet end and a device water outlet end; the circulating water pump, the first fluid flow channel and the second fluid flow channel are connected in series between the second device water inlet end and the device water outlet end.

[0022] As an optional aspect of the present application, a buffer container is further provided; the buffer container has a first container water outlet end and a container water inlet end lower than the first container water outlet end; the first container water outlet end is connected to the water inlet end of the feed water pump; and the container water inlet end is connected to the water outlet end of the second fluid flow channel.

[0023] As an optional aspect of the present application, the buffer container further has a second container water outlet end for outputting water outward; the second container water outlet end is lower than the container water inlet end; and the buffer container is further provided with an exhaust valve at an upper portion thereof.

[0024] As an optional aspect of the present application, the preheating unit is a plate heat exchanger, a shell-and-tube heat exchanger or a double-pipe heat exchanger.

[0025] As an optional aspect of the present application, the steam generating device is a small-sized exempted steam boiler, and the water volume thereof is less than 50L.

[0026] A steam generating system, comprising:

[0027] The steam generating device as any one of the above; the steam generating device has a device water inlet end and a device water outlet end;

[0028] A water storage tank; the device water inlet end and the device water outlet end of the steam generating device are respectively connected to the water storage tank; and the device water inlet end is higher than the device water outlet end. Advantageous effects

[0029] The steam generating device and system of the present application can not only guarantee the utilization rate of the heat generated by gas combustion, but also avoid affecting the steam generating speed and the evaporation capacity of the steam generator on the basis of improving the water volume and realizing true safety and exemption from inspection.

[0030] The steam generating device and system thereof of the present disclosure recover flue gas waste heat on the atmospheric side condenser, heat water, and then transfer the heat of the water to boiler feed water on the high-pressure side through a preheating unit (which can be a plate heat exchanger, or a shell-and-tube heat exchanger, or a double-pipe heat exchanger), effectively improving the utilization rate of gas combustion heat and avoiding the problem of increased safety risk caused by the excessive water volume on the pressure side of the waste heat recovery unit due to direct recovery of flue gas waste heat.

[0031] The steam generating device disclosed in the present application is provided with a preheating unit, which absorbs heat from the medium in the condenser and quickly transfers the heat to the boiler feed water through the preheating unit, and then evaporates steam in the furnace body, thereby improving the thermal efficiency and real-time steam production rate of the system. The feed water booster pump (feed water pump) is arranged at the outlet of the water tank and located upstream of the heat exchange unit. The water inlet of the feed water pump does not have resistance from the heat exchanger, which ensures the inlet pressure of the pump suction port, avoids the idling and cavitation of the water pump, improves the reliability of the boiler feed water, and solves the problem of untimely feed water caused by resistance of the heat exchange unit upstream.

[0032] The steam generating device disclosed in the present application is provided with a preheating unit, which absorbs heat from the medium in the condenser and quickly transfers the heat to the boiler feed water through the preheating unit, and then evaporates steam in the furnace body, thereby improving the thermal efficiency and real-time steam production rate of the system. The feed water booster pump (feed water pump) is arranged at the outlet of the water tank and located upstream of the heat exchange unit. The water inlet of the feed water pump does not have resistance from the heat exchanger, which ensures the inlet pressure of the pump suction port, avoids the idling and cavitation of the water pump, improves the reliability of the boiler feed water, and solves the problem of untimely feed water caused by resistance of the heat exchange unit upstream.

[0033] The specific embodiments of the present application are disclosed in detail in the following description and drawings, and the principles of the present application can be adopted in the manner indicated. It should be understood that the embodiments of the present application are not limited in scope as a result.

[0034] Features described and / or illustrated with respect to one embodiment can be used in the same or similar manner in one or more other embodiments, in combination with or in place of features in other embodiments.

[0035] It should be emphasized that the term "comprises / comprising" as used herein indicates the presence of the stated features, integers, steps or components, but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 is a water path structure diagram of a steam generating device provided by an embodiment of the present disclosure.

[0038] Figure 2 is a water path structure diagram of a steam generating device provided by another embodiment of the present disclosure. DETAILED DESCRIPTION

[0039] In order for those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0040] It should be noted that when an element is referred to as "provided on" another element, it can be directly on the other element or there can be a middle element. When an element is referred to as "connected" to another element, it can be directly connected to the other element or there can be a middle element. The terms "vertical", "horizontal", "left", "right", and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation.

[0041] 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 the present application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0042] Referring to Figure 1 The present disclosure provides a steam generating device, which is applicable to but not limited to a free inspection type steam generator with a water volume of less than 50L.

[0043] Specifically, the steam generating device comprises a main heat exchange unit, a secondary heat exchange unit 21, and a preheating unit 32. The main heat exchange unit defines a first flue gas flow channel and a steam generating flow channel. Water in the steam generating flow channel exchanges heat with flue gas in the first flue gas flow channel to generate steam. The preheating flow channel is further connected in series with a check valve 40 (one-way valve) and a feed water pump 31 upstream of the water inlet end (body water inlet end 15) of the steam generating flow channel. The check valve 40 and the preheating flow channel are connected in series between the feed water pump 31 and the water inlet end of the steam generating flow channel. The check valve 40 can be connected in series upstream or downstream of the preheating flow channel.

[0044] In the present embodiment, a check valve 40 (one-way valve) is connected in series between the water outlet end of the preheating flow passage of the preheating unit 32 and the water inlet end of the main heat exchange unit. A feed water pump 31 is further connected in series upstream of the check valve 40. Further, the feed water pump 31 is connected in series upstream of the water inlet end of the preheating flow passage. The feed water pump 31 is connected in series upstream of the water inlet end of the preheating flow passage; and the check valve 40 is connected in series upstream of the water inlet end of the steam generation flow passage and downstream of the water outlet end of the preheating flow passage.

[0045] The secondary heat exchange unit 21 defines a second flue gas flow passage and a first fluid flow passage which are communicated downstream of the first flue gas flow passage. The first flue gas flow passage and the second flue gas flow passage are communicated through the flue gas communication pipe 11. The fluid of the first fluid flow passage exchanges heat with the flue gas of the second flue gas flow passage to be heated. The preheating unit 32 defines a second fluid flow passage communicated downstream of the first fluid flow passage and a preheating flow passage communicated upstream of the steam generation flow passage. The water of the preheating flow passage exchanges heat with the fluid of the second fluid flow passage to be heated.

[0046] The main heat exchange unit includes a steam generation body 1 (furnace body) having a body water inlet end 15 for inputting water and a flue gas outlet end for outputting flue gas. The steam generation body 1 is provided with a single ring of vertical heat exchange pipes arranged in the circumferential direction. The inside of the vertical heat exchange pipes forms a steam generation flow passage, and the outside forms a first flue gas flow passage. The first flue gas flow passage is communicated with the flue gas outlet end. The steam generation body 1 is only provided with a single ring of vertical heat exchange pipes to reduce the water volume.

[0047] The steam generation device of the present embodiment is provided with a preheating unit 32, and the heat absorbed by the medium in the secondary heat exchange unit 21 is quickly transferred to the boiler (main heat exchange unit) feed water through the preheating unit 32, and then evaporated to produce steam in the furnace body, thereby improving the system thermal efficiency and real-time steam production rate. The feed water booster pump (feed water pump 31) is arranged at the outlet of the water storage tank to ensure the inlet pressure of the pump inlet, avoid the water pump idling and cavitation, and improve the reliability of the boiler feed water; the arrangement of the check valve 40 prevents the high-temperature and high-pressure fluid in the furnace body from flowing back to the pump body when the equipment is stopped, which can cause damage to the pump body. At the same time, it is more suitable for the latest boiler water volume range, and ensures that the water volume of the equipment is within the safe and exempted inspection range.

[0048] As can be seen, the secondary heat exchange unit 21 of the present embodiment recovers the waste heat of the flue gas and then transfers the heat to the water supply of the steam generation body 1 through the preheating unit 32 to preheat the water supply of the steam generation body 1, thereby realizing heat recovery of the flue gas and ensuring the utilization rate of the heat generated by the gas combustion.

[0049] And, the multi-stage heat exchange formed by the secondary heat exchange unit 21 and the preheating unit 32 can avoid the secondary heat exchange unit 21 being connected in series with the main heat exchange unit in the water circuit as a pressure-bearing component, thereby improving the water volume of the steam generating device to meet the 50L or less exemption requirement.

[0050] The steam generating body 1 is used for heating water to form steam. For the structure of the steam generating body 1, reference can be made to the description in the Chinese patent application with the application number 202210081118.6 and the invention name “New type of through-flow steam generator or steam boiler and heat exchange unit thereof” filed by the applicant on January 24, 2022, and the repeated parts will not be described herein.

[0051] In the embodiment, the secondary heat exchange unit 21 is a condensing heat exchanger for recovering the waste heat of the flue gas output from the steam generating body 1. The fluid medium of the secondary heat exchange unit 21 is water. The first fluid flow channel includes the internal flow channel of the condensing heat exchange tube in the condensing heat exchanger, and the second flue gas flow channel is defined in the interior of the condensing heat exchanger shell. The condensing heat exchanger is also connected with a circulating water pump 22 for driving the flow of fluid. The water circuit in which the secondary heat exchange unit 21 is located is an independent water circuit, and thus the requirement for the fluid driving pump thereof is lower, and therefore the circulating water pump 22 in the embodiment is a fixed-frequency water pump.

[0052] As shown in Figure 1 , the secondary heat exchange unit 21 is located on the heat exchange water circuit 2 having a second device water inlet end and a device water outlet end 20. The first fluid flow channel of the secondary heat exchange unit 21, the circulating water pump 22 and the second fluid flow channel are connected in series on the heat exchange water circuit 2. The circulating water pump 22, the first fluid flow channel and the second fluid flow channel are sequentially connected between the second device water inlet end and the device water outlet end 20.

[0053] To avoid the suction influence of the complex flow channel of the condensing heat exchanger on the circulating water pump 22, the circulating water pump 22 is connected in series between the second device water inlet end and the water inlet end 25 of the first fluid flow channel. Of course, in other embodiments, the circulating water pump 22 can also be connected in series between the water outlet end 26 of the first fluid flow channel and the water inlet end 38 of the second fluid flow channel, and in addition, the circulating water pump 22 can also be connected in series between the water outlet end 39 of the second fluid flow channel and the device water outlet end 20, and the present disclosure is not limited thereto.

[0054] In the embodiment, the heat exchange water circuit 2 in which the secondary heat exchange unit 21 is located is an open circulation water circuit, and the second water inlet end 20 and the device water outlet end 20 are respectively connected with the same water storage tank, which can be provided by, for example, a water tank or a water tower.

[0055] The body water inlet end 15 is communicated with a water supply water path 3 having a first device water inlet end. The heat exchange water path 2 and the water supply water path 3 do not interfere with each other. The water flow of the water supply water path 3 is higher than the water flow of the heat exchange water path 2 to meet the demand of the furnace body generating steam. The preheating unit 32 is a plate heat exchanger, and the preheating flow path is connected in series between the first device water inlet end and the body water inlet end 15 on the water supply water path 3.

[0056] Further, the water supply water path 3 is also provided with a feed water pump 31 connected in series with the preheating flow path. In order to meet the requirement of water flow for steam generation, the feed water pump 31 in the embodiment is a variable frequency water pump. In order to avoid the pressure bearing of the plate heat exchanger, reduce the water volume and reduce the safety risk, the feed water pump 31 is connected in series between the water outlet end 35 of the preheating flow path and the body water inlet end 15.

[0057] The water supply water path 3 and the heat exchange water path 2 can be communicated with the same water source, and then the waste heat output by the heat exchange water path 2 is further recycled. The heat exchange water path 2 serves as the heat source of the water supply water path 3, and the waste heat of the flue gas is recycled to the water supply of the steam generation body 1 through the preheating unit 32, realizing multi-stage and multiple utilization of the heat of gas combustion and reducing the loss of system heat.

[0058] The feed water pump 31 is a booster pump, and the feed water pump 31 is connected in series between the water inlet end 34 of the preheating flow path and the first device water inlet end. Compared with the condensing heat exchanger, the plate heat exchanger has a small internal volume, and even if it is connected downstream of the feed water pump 31, it can bear pressure and has little effect on the water volume of the steam generation device, and can also reduce the pumping effect of the feed water pump 31, ensuring the stability of the water supply. The first device water inlet end and the second device water inlet end can be different water inlet ends, or can be the same water inlet end. In the embodiment, the first device water inlet end and the second device water inlet end are the same device water inlet end 30, and the two are communicated through a three-way structure. The feed water pump 31 is a centrifugal pump, and the device water inlet end 30 is lower than the device water outlet end 20. The device water inlet end 20 can be communicated with the top of the water storage tank 5, and the device water inlet end 30 can be communicated with the bottom of the water storage tank 5, so as to provide a certain water inlet pressure for the feed water pump 31 through the liquid level of a certain height in the water storage tank 3, and ensure the normal work of the feed water pump 31.

[0059] The steam generation device of the embodiment forms three-stage heat exchange by adding a preheating unit 32 to fully utilize the heat generated by gas combustion. The heat exchange water path 2 does not need to bear pressure, and through three-stage heat exchange, the system heat is almost not lost, and the problem of increased safety risk caused by the large water volume of the pressure-bearing side of the preheating unit due to direct recycling of the waste heat of flue gas can be solved.

[0060] The circulating water pump 22 and the feed water pump 31 are located in two water paths which do not interfere with each other. The pump efficiency of the circulating water pump 22 can maintain the liquid level of the steam generation body 1 stable. The circulating water pump 22 and the feed water pump 31 do not interfere with each other and can run stably and continuously. The stable operation of the entire water path system is ensured, and the steam generation can continue.

[0061] Moreover, the water in the heat exchange water path 2 returns to the water storage tank 5 finally. The water which has stored heat after heat exchange by the preheating unit 32 heats the water in the water storage tank. The water in the water storage tank is preheated in the water storage tank and the third heating assembly for many times before the cold water is supplied to the steam generation body 1. The temperature of the water input to the steam generation body 1 is improved, and the real-time steam generation is ensured.

[0062] Figure 2 A water path diagram of the steam generation device of another embodiment is provided. In the embodiment, the steam generation device is provided with a buffer container 70. The buffer container 70 is connected to the upstream of the feed water pump 31. The buffer container 70 is connected to the downstream of the heat exchange unit. Specifically, the buffer container 70 has a first container water outlet end 71 and a container water inlet end 71 which is lower than the first container water outlet end 72. The first container water outlet end 72 is connected to the water inlet end of the feed water pump 31. The container water inlet end 71 is connected to the water outlet end 39 of the second fluid flow channel.

[0063] The water after the open circulating water path passes through the preheating unit 32 is collected again by the buffer container 70 and is reused as the water inlet of the feed water pump 31. The heat recovery efficiency is further improved.

[0064] The buffer container 70 is a normally closed container. The circulating water is collected by the buffer container 70, and the direct entry of the circulating water into the water storage tank is avoided to prevent the waste of part of the heat. The buffer container 70 also has a second container water outlet end 73 which outputs water outward. The second container water outlet end 73 is lower than the container water inlet end 71. An exhaust valve is arranged at the upper part of the buffer container 70. The second container water outlet end 73 is connected to the device water outlet end 20. The device water outlet end 20 is connected to the water storage tank 5. The water at the upper part of the buffer container 70 has a higher temperature and is supplied to the feed water pump 31. The second fluid flow channel which flows out of the preheating unit 32 enters the lower part of the buffer container 70. To reduce the water temperature of the buffer container 70 which is supplied to the water storage tank 5 and ensure the heat recovery efficiency, the second container water outlet end 73 of the buffer container 70 which supplies water to the water storage tank 5 is located at the lowermost part of the container water inlet end 71 of the first container water outlet end 72.

[0065] In the embodiment, the device water inlet end 30 is higher than the device water outlet end 20 and is connected to the upstream of the circulating water pump 22. Unlike the prior art, the device water inlet end 30 is connected to the downstream of the circulating water pump 22. Figure 1In the illustrated embodiment, water is simultaneously supplied to both the circulating water pump and the feed water pump 31. The steam generator in this embodiment has a single water inlet, and water from the storage tank 5 is only supplied to the circulating water pump 22. Water from the buffer container 70 is simultaneously supplied to the storage tank 5 and the feed water pump 31.

[0066] It should be noted that the buffer container 70 in this embodiment can refer to the buffer container 70 in the steam generating device of patent CN115614722A, and the similarities will not be repeated.

[0067] One embodiment of this disclosure also provides a steam generating system, comprising: a steam generating device as described in any embodiment. The steam generating system further includes a water storage tank 5. The water storage tank 5 can be provided by an external water tank, or by a water tower or water tank; this disclosure is not limited thereto. The steam generating device includes a water supply path having a first device inlet and a heat exchange path 2 having a second device inlet and a device outlet 20. The first device inlet is connected to the water storage tank, and the second device inlet and the device outlet 20 are connected to the water storage tank 5.

[0068] 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 utility model subject matter.

Claims

1. A steam generating apparatus, characterized by comprising: Comprising: a main heat exchange unit defining a first flue gas flow channel and a steam generation flow channel; water in the steam generation flow channel exchanges heat with flue gas in the first flue gas flow channel to generate steam; a preheating unit defining a preheating flow channel for heating water in the preheating flow channel; wherein the preheating flow channel is further connected in series with a check valve and a feed water pump upstream of the steam generation flow channel; the check valve and the preheating flow channel are connected in series between the feed water pump and a water inlet end of the steam generation flow channel.

2. The steam generating apparatus as claimed in claim 1, wherein, The feed water pump is connected in series upstream of the preheating flow channel; the check valve is connected in series upstream of the steam generation flow channel and downstream of the preheating flow channel.

3. The steam generating apparatus as claimed in claim 1, wherein, Further comprising a secondary heat exchange unit; the secondary heat exchange unit defines a second flue gas flow channel connected downstream of the first flue gas flow channel and a first fluid flow channel; fluid in the first fluid flow channel exchanges heat with flue gas in the second flue gas flow channel to be heated; The preheating unit further defines a second fluid flow channel connected downstream of the first fluid flow channel; water in the preheating flow channel exchanges heat with fluid in the second fluid flow channel to be heated.

4. The steam generating apparatus as claimed in claim 3, wherein, The main heat exchange unit comprises a steam generation body having a body water inlet end for inputting water and a flue gas outlet end for outputting flue gas; a plurality of vertical heat exchange pipes are arranged in the steam generation body; the inside of the vertical heat exchange pipes forms the steam generation flow channel, and the outside of the vertical heat exchange pipes forms the first flue gas flow channel; the secondary heat exchange unit is a condensing heat exchanger for recovering waste heat of flue gas from the flue gas outlet end of the steam generation body; the condensing heat exchanger is further connected with a circulating water pump for driving fluid flow.

5. The steam generating apparatus as claimed in claim 4, wherein, The steam generation device has a first device water inlet end; the feed water pump is connected in series between the device water inlet end and a water inlet end of the preheating flow channel.

6. The steam generating apparatus as claimed in claim 5, wherein, The steam generation device has a second device water inlet end and a device water outlet end; the circulating water pump, the first fluid flow channel, and the second fluid flow channel are connected in series between the device water inlet end and the device water outlet end.

7. The steam generating apparatus as claimed in claim 5, wherein, Further comprising a buffer container; the buffer container has a first container water outlet end and a container water inlet end lower than the first container water outlet end; the first container water outlet end is connected to a water inlet end of the feed water pump; the container water inlet end is connected to a water outlet end of the second fluid flow channel.

8. The steam generating apparatus as claimed in claim 7, wherein, The buffer container further has a second container water outlet end for outputting water outward; the second container water outlet end is lower than the container water inlet end; an upper portion of the buffer container is further provided with an exhaust valve.

9. The steam generating apparatus as claimed in claim 6, wherein, The preheating unit is a plate heat exchanger, a shell-and-tube heat exchanger, or a double-pipe heat exchanger; the steam generation device is a small exempt steam boiler with a water volume of less than 50L.

10. A steam generating system, wherein, Comprising: The steam generation device of any one of claims 1-9; a water storage tank; A device water inlet end and a device water outlet end of the steam generation device are respectively connected to the water storage tank.

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