A phase change clean steam generator

Abstract

This utility model discloses a phase change clean steam generator, including a generator body. Air heated by a secondary air preheater is drawn in by a blower and mixed with natural gas fuel in an air-fuel mixer to form premixed fuel gas, which is then burned within the generator body. High-temperature steam enters a clean steam heat exchanger assembly and exchanges heat with internal water to form low-pressure steam. The condensate formed after the high-temperature steam heat exchange is returned to the generator body. A steam micro-superheater exchanges heat with saturated steam in finned serpentine steam superheating tubes to form sub-low-temperature flue gas, which then enters a primary stainless steel energy saver. This flue gas is cooled by the primary stainless steel energy saver to become ultra-low-temperature flue gas, which then enters a secondary air preheater and exchanges heat with combustion air before being discharged. This utility model's clean steam generator has the advantages of no scale buildup on the heating surface, long service life, no need for complicated maintenance, and cost reduction through material savings.

Description

Technical Field

[0001] This utility model relates to the field of steam generator technology, and in particular to a phase change clean steam generator. Background Technology

[0002] According to the requirements of the "Boiler Safety Technical Regulations (Amendment No. 1)," a new type of closed-loop circulating boiler needs to be researched. This regulation stipulates that the initial water injection volume before boiler use must be less than 30L. Therefore, based on this requirement, a new phase change structure steam generator is developed, combining a phase change water-cooled low-NOx combustion boiler body with an economizer and an air preheater.

[0003] Therefore, based on the above-mentioned technical problems, those skilled in the art urgently need to develop a phase change clean steam generator. Utility Model Content

[0004] The purpose of this invention is to provide a phase change clean steam generator, which has the advantages of no scale buildup on the heating surface, long service life, no need for complicated maintenance, and saving materials and reducing costs.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] This utility model discloses a phase change clean steam generator, which includes:

[0007] The generator body draws air heated by a secondary air preheater through a blower, mixes it with natural gas fuel in an air-fuel mixer to form a premixed combustible gas, and burns it in the generator body.

[0008] A clean steam heat exchanger assembly is connected to the primary phase change steam chamber of the generator body via a primary steam pipeline to receive the primary high-temperature steam delivered by the primary phase change steam chamber of the generator body. The condensate formed by the primary high-temperature steam in the clean steam heat exchanger assembly after heat exchange is then transported back to the generator body.

[0009] The steam micro-superheater connected to the generator body forms sub-low temperature flue gas through heat exchange between the flue gas and the saturated steam in the finned serpentine steam superheater tube. This sub-low temperature flue gas enters the first-stage stainless steel energy saver. After being cooled by the first-stage stainless steel energy saver, this sub-low temperature flue gas becomes ultra-low temperature flue gas. This ultra-low temperature flue gas enters the second-stage air preheater and exchanges heat with the combustion air before being discharged.

[0010] Furthermore, the blower is connected to the secondary air preheater via an air pipeline to draw in the heated combustion air;

[0011] An air regulating valve is installed between the blower and the air-fuel mixer;

[0012] The generator body includes:

[0013] A premixed gas chamber connected to the air-fuel mixer;

[0014] A finned water-cooled tube combustor is arranged inside the generator body and close to the premixed gas chamber. The premixed gas chamber evenly distributes the premixed gas to the finned water-cooled tube combustor and delivers it to each burner.

[0015] The generator body is also equipped with a furnace radiant hot water pipe and a convective hot water-fire jacket. The upper part of the generator body forms a primary phase change steam chamber and an exhaust smoke box.

[0016] The premixed gas at the burner of the finned water-cooled tube burner produces a high-temperature, low-NOx flame. After absorbing heat through the radiant hot water pipe in the furnace, the flame is cooled to become high-temperature flue gas. Subsequently, it is cooled to low-temperature flue gas through heat exchange on the external convective heating surface of the convective hot water-fire jacket. Then, this low-temperature flue gas is guided into the convective hot water-fire jacket through the conversion box at the bottom of the generator body and undergoes convective heat transfer to form secondary low-temperature flue gas, which is then discharged from the exhaust smoke box.

[0017] Furthermore, water with a volume of less than 30L injected into the generator body is heated into primary high-temperature steam through heat exchange, and the primary high-temperature steam is delivered to the clean steam heat exchanger group.

[0018] Furthermore, the clean steam heat exchanger assembly includes multiple sets of shell-and-tube type all-stainless steel steam-to-steam heat exchangers.

[0019] The shell-and-tube all-stainless steel steam-to-steam heat exchanger includes:

[0020] A stainless steel clean steam chamber located at the top;

[0021] The stainless steel water supply chamber is located at the bottom; and

[0022] The stainless steel shell is located in the middle, and stainless steel steam heat exchange tubes are installed inside the stainless steel shell.

[0023] Furthermore, the clean steam generator has a two-stage energy-saving system;

[0024] The secondary energy-saving system includes a primary stainless steel energy-saving unit and a secondary air preheater.

[0025] Furthermore, the first-level stainless steel energy saver includes:

[0026] The energy-saving device has a stainless steel housing, an energy-saving device flue gas inlet located at the upper part of the stainless steel housing, and an energy-saving device flue gas outlet located at the lower part of the stainless steel housing.

[0027] Stainless steel heat exchange tubes are installed inside the stainless steel shell of the energy saver;

[0028] The sub-low temperature flue gas enters from the flue gas inlet of the energy-saving device's stainless steel shell and exits from the flue gas outlet of the energy-saving device;

[0029] Water enters from below the stainless steel heat exchange tube and exits from the top of the stainless steel heat exchange tube after several turns.

[0030] Furthermore, the secondary air preheater includes:

[0031] An air preheater shell, wherein the upper part of the air preheater shell has a preheater flue gas outlet, and the lower part of the air preheater shell has a preheater flue gas inlet; and

[0032] Heat exchange sleeves installed inside the air preheater shell;

[0033] Flue gas enters the heat exchanger tube through the flue gas inlet of the preheater and exits through the flue gas outlet of the preheater;

[0034] Air enters the air preheater housing from the upper part of the secondary air preheater and exits from the lower part of the secondary air preheater and is delivered to the blower inlet.

[0035] Furthermore, the clean steam generator also includes:

[0036] High-level water supply tank;

[0037] A water pump is installed on the elevated water supply tank, and the water pump is connected to the water supply pipeline.

[0038] Furthermore, the clean steam generator also includes a steam micro-superheater;

[0039] The steam micro superheater includes:

[0040] Micro superheater smoke box and finned serpentine steam superheater tubes;

[0041] The steam output from the clean steam heat exchanger enters the finned serpentine steam superheater tube and exchanges heat with the flue gas outside the tube to evaporate some of the moisture.

[0042] In the above technical solution, the phase change clean steam generator provided by this utility model has the following beneficial effects:

[0043] The clean steam generator of this invention has the advantages of no scale buildup on the heating surface, long service life, no need for complicated maintenance, and saving materials to reduce costs. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0045] Figure 1 A schematic diagram of the structure of a phase change clean steam generator provided in this embodiment of the present invention. Figure 1 ;

[0046] Figure 2 A schematic diagram of the structure of a phase change clean steam generator provided in this embodiment of the present invention. Figure 2 .

[0047] Explanation of reference numerals in the attached figures:

[0048] 1. Generator body; 2. Clean steam heat exchanger assembly; 3. Primary stainless steel economizer; 4. Secondary air preheater; 5. Steam piping system; 7. Steam micro-superheater;

[0049] 101. Blower; 102. Air regulating valve; 103. Air-fuel mixer; 104. Premixed gas chamber; 105. Primary steam chamber; 106. Finned water-cooled tube combustion chamber; 107. Furnace radiant heat transfer tubes; 108. Flue gas upper smoke box; 109. Convection heat transfer fire jacket; 110. Conversion box;

[0050] 201. Stainless steel clean steam chamber; 202. Steam heat exchange tubes;

[0051] 301. Eco-friendly gas inlet; 302. Stainless steel heat exchange tube; 303. Eco-friendly stainless steel shell; 304. Eco-friendly gas outlet;

[0052] 401. Air preheater shell; 402. Heat exchanger sleeve; 403. Preheater flue gas inlet; 404. Preheater flue gas outlet;

[0053] 501. Primary steam pipeline; 502. Secondary steam output pipeline for heat exchange;

[0054] 601. Elevated water supply tank; 602. Water supply pipeline for water pump; 603. Water supply pump;

[0055] 701. Micro superheater smoke box; 702. Finned serpentine steam superheater tube. Detailed Implementation

[0056] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0057] See Figures 1 to 2 As shown;

[0058] This embodiment discloses a phase change clean steam generator, which includes:

[0059] The generator body 1 draws air heated by the secondary air preheater 4 through the blower 101, mixes it with natural gas fuel in the air-fuel mixer 103 to form a premixed combustible gas, and burns it in the generator body 1.

[0060] A clean steam heat exchanger group 2 is connected to the primary phase change steam chamber 105 of the generator body 1 through a primary steam pipeline to receive the primary high-temperature steam delivered by the primary phase change steam chamber 105 of the generator body 1. The condensate formed by the primary high-temperature steam in the clean steam heat exchanger group 2 after heat exchange is transported back to the generator body 1.

[0061] The steam micro-superheater 7, which is connected to the generator body 1, forms sub-low temperature flue gas through heat exchange between the flue gas and the saturated steam in the finned serpentine steam superheater tube 702. This sub-low temperature flue gas enters the first-stage stainless steel energy saver 3. After being cooled by the first-stage stainless steel energy saver 3, this sub-low temperature flue gas becomes ultra-low temperature flue gas. This ultra-low temperature flue gas enters the second-stage air preheater 4 and exchanges heat with the combustion air before being discharged.

[0062] Specifically, the clean steam generator of this embodiment includes a generator body 1, a secondary air preheater 4, a primary stainless steel energy saver 3, and a clean steam heat exchanger group 2; preferably, the blower 101 of this embodiment is connected to the secondary air preheater 4 through an air pipeline to draw the heated combustion air; an air regulating valve 102 is installed between the blower 101 and the air-fuel mixer 103.

[0063] The generator body 1 includes a premixed gas chamber 104 connected to the air-fuel mixer 103; and a finned water-cooled tube combustor 106 arranged inside the generator body 1 and close to the premixed gas chamber 104. The premixed gas chamber 104 evenly distributes the premixed gas to the finned water-cooled tube combustor 106 and delivers it to each burner.

[0064] The generator body 1 is also equipped with a furnace radiant hot water pipe 107 and a convective hot water-fire jacket 109. The upper part of the generator body 1 forms a primary phase change steam chamber 105 and a flue gas exhaust box 108.

[0065] The premixed gas at the burner of the finned water-cooled tube combustion chamber 106 produces a high-temperature, low-NOx flame. After absorbing heat through the furnace radiant hot water pipe 107, the flame cools down to become high-temperature flue gas. Subsequently, it is cooled down to low-temperature flue gas through heat exchange on the external convective heating surface of the convective hot water-fire jacket 109. Then, this low-temperature flue gas is guided into the convective hot water-fire jacket 109 through the conversion box 110 at the bottom of the generator body 1 and undergoes convective heat transfer to form a secondary low-temperature flue gas, which is then discharged from the exhaust upper smoke box 108.

[0066] In order to meet the requirements for steam generators in the "Boiler Safety Technical Regulations (Amendment No. 1)", in this embodiment, water with a volume of less than 30L injected into the generator body 1 is heated into primary high-temperature steam through heat exchange, and the primary high-temperature steam is delivered to the clean steam heat exchanger group 2.

[0067] After being heated by the secondary air preheater 4, the air is fed into the air regulating valve 102 through the air supply pipe and enters the air-fuel mixer 103 to be fully mixed with the natural gas fuel that enters at the same time to become premixed gas. Then it enters the premixed gas chamber 104 of the generator body 1 and is evenly distributed to the finned water-cooled tube burner 106 for combustion to produce a high-temperature low-NOx flame. After absorbing heat through the furnace radiant heating surface hot water pipe 107, it is cooled to become high-temperature flue gas. Then it is cooled to low-temperature flue gas through the external convective heating surface of the convective hot water-fire jacket 109. After being turned by the conversion box 110, it enters the convective hot water-fire jacket 109 for the final convective heat transfer process to become low-temperature flue gas. Finally, it is discharged through the exhaust upper smoke box 108.

[0068] Meanwhile, the water-side process in this embodiment is as follows: a 30L water cup fixed inside the generator body 1 is heated into high-temperature, high-pressure steam. This high-temperature steam is then supplied to the clean steam heat exchanger group 2 through the primary phase change steam chamber 105 for heat exchange, forming condensate. The condensate then returns to the generator body 1 and is reheated into high-temperature steam, repeating the cycle. The clean steam heat exchanger absorbs the heat from the primary high-temperature steam and produces secondary clean low-pressure steam, which then enters the finned serpentine steam superheater tube 702 of the steam micro-superheater for heating and becoming superheated steam for use.

[0069] In this embodiment, the flue gas enters the finned serpentine steam superheater 702 of the steam micro-superheater 7, where the saturated steam is heated into micro-superheated clean steam for use at the steam consumption point. Simultaneously, the sub-low temperature flue gas, after slight cooling, enters the first-stage shell-and-tube economizer 3. After heat exchange with clean water in the economizer shell 303 via stainless steel heat exchange tubes 302, it is cooled to ultra-low temperature flue gas. This ultra-low temperature flue gas then enters the second-stage air preheater 4 through the economizer's flue gas outlet, where it finally exchanges heat with combustion air, cools, condenses, and is ultimately discharged through the exhaust port. This flue gas process ultimately reduces the temperature below the flue gas dew point, resulting in a final clean steam generator thermal efficiency of over 100%, forming micro-superheated steam with a steam dryness greater than 100%.

[0070] Preferably, the clean steam heat exchanger group 2 in this embodiment includes multiple sets of shell-and-tube type all-stainless steel steam-to-steam heat exchangers;

[0071] More specifically, the shell-and-tube type all-stainless steel steam-to-steam heat exchanger of this embodiment includes a stainless steel clean steam chamber 201 at the top, a stainless steel feedwater chamber at the bottom, and a stainless steel shell in the middle, with stainless steel steam heat exchange tubes 202 installed inside the stainless steel shell.

[0072] First, regarding the generator body 1 in this embodiment, its single water injection is less than 30L, resulting in a long service life, small size, material savings, and low nitrogen oxide emissions. The blower 101 directs the combustion air heated by the secondary air preheater 4 to the air-fuel mixer 103 for combustion. In this embodiment, the blower 101 uses frequency conversion to control its speed, adjusting the speed according to the blower frequency to achieve the actual air volume required, saving energy. Simultaneously, the air regulating valve 102 between the blower 101 and the air-fuel mixer 103 can adjust the airflow with a baffle, precisely controlling the amount of air entering the air-fuel mixer 103 in conjunction with the blower 101. This ensures complete combustion of the gas while maintaining NOx emissions below 30 mg / L, meeting environmental requirements. Second, the air-fuel mixer 103 in this embodiment uses a porous ring to evenly introduce the gas into the duct cross-section, fully mixing natural gas and air, ensuring uniform premixing, achieving uniform combustion, and providing a good nitrogen reduction effect.

[0073] Furthermore, in this embodiment, the premixed gas chamber 104 of the generator body 1 serves as a transition distribution chamber, which can evenly distribute the mixed natural gas to each burner channel on the water-cooled burner. This even distribution stabilizes the mixed gas pressure and prevents fluctuations. The finned water-cooled tube burner 106, as the core component of the water-cooled burner, uses stainless steel finned tubes as the main component for cooling the flame. The fins, formed through molding, serve as burners, creating a square combustion surface that disperses the combustion flame across a single surface. The finned channels in this embodiment increase the resistance to gas flow, preventing backfire and deflagration hazards during combustion, thus ensuring good safety. Simultaneously, the finned water-cooled tubes increase the flame cooling area, further reducing the initial flame temperature.

[0074] Meanwhile, in this embodiment, the furnace radiant heat transfer pipe 107 and the convective heat transfer fire-water jacket 109 of the generator body 1 can adopt a composite heat transfer jacket structure. As the main heat transfer component of the furnace body, the furnace only absorbs the radiant heat of the flame, while the heat transfer jacket performs primary heat transfer of water to reduce the high-temperature flue gas. Then, through the internal threaded tube structure, it performs secondary heat transfer with water. This can reduce the volume of the generator body 1, reduce the amount of water in the phase change chamber, increase heat transfer, and save steel. In addition, the conversion smoke box 110 and the exhaust smoke box 108 in this embodiment serve as channels for flue gas conversion flow. Finally, the water in the generator body 1 is heated by the radiant flame and high-temperature flue gas to generate primary high-temperature and high-pressure steam, which is then collected in the primary phase change steam chamber 105 and transported to the secondary low-pressure steam at the clean heat exchanger through the primary steam pipe.

[0075] In this embodiment, the shell-and-tube all-stainless steel steam-to-steam heat exchanger of the clean steam heat exchanger group 2 can be a non-inspection-required shell-and-tube all-stainless steel steam-to-steam heat exchanger. It uses primary high-temperature, high-pressure steam to transfer heat to clean water in the heat exchange tubes, resulting in secondary low-temperature, low-pressure clean steam, achieving the output of medical-grade clean steam. The heat exchanger adopts dimensions that meet the non-inspection-required standards to accommodate the overall non-inspection of the generator. This structure, with its multi-modal combination, can meet different steam volume requirements, is standardized in production, convenient to manufacture, and uses stainless steel to ensure the cleanliness of the steam.

[0076] Preferably, the clean steam generator of this embodiment has a two-stage energy-saving system; the two-stage energy-saving system includes a first-stage stainless steel energy saver 3 and a second-stage air preheater 4.

[0077] Specifically, the first-stage stainless steel energy saver 3 in this embodiment includes an energy saver stainless steel shell 303, an energy saver flue gas inlet 301 located at the upper part of the energy saver stainless steel shell 303, and an energy saver flue gas outlet 304 located at the lower part of the energy saver stainless steel shell 303; and a stainless steel heat exchange tube 302 disposed inside the energy saver stainless steel shell 303.

[0078] The low-temperature flue gas enters through the economizer flue gas inlet 301 of the economizer stainless steel shell 303 and exits through the economizer flue gas outlet 304; water enters from below the stainless steel heat exchange tube 302 and exits from the upper end of the stainless steel heat exchange tube 302 after several turns.

[0079] In this embodiment, the primary stainless steel energy-saving device 3 adopts a full counter-current heat exchange method to ensure maximum temperature difference and optimal heat transfer. This maximizes the recovery of heat from the flue gas, while the thin-tube heat exchanger structure allows for better heat transfer between the flue gas and water.

[0080] Secondly, the secondary air preheater 4 in this embodiment includes an air preheater shell 401, an air preheater flue gas outlet 404 at the upper part of the air preheater shell 401, a preheater flue gas inlet 403 at the lower part of the air preheater shell 401, and a heat exchange sleeve 402 disposed inside the air preheater shell 401; flue gas enters the heat exchange sleeve 402 through the preheater flue gas inlet 403 and is discharged through the preheater flue gas outlet 404; air enters the air preheater shell 401 from the upper part of the secondary air preheater 4 and is discharged from the lower part of the secondary air preheater 4 and transported to the inlet of the blower 101.

[0081] In this embodiment, the secondary air preheater 4 adopts a full counter-current heat exchange method to ensure the maximum temperature difference and optimal heat transfer, and to maximize the recovery of waste heat in the flue gas. The shell-and-tube heat exchange tubes ensure that the cold air can be better distributed and exchanged with the flue gas evenly.

[0082] Preferably, the clean steam generator in this embodiment further includes a high-level water supply tank 601; wherein, a water supply pump 603 is provided on the high-level water supply tank 601, and the water supply pump 603 is connected to the water supply pump pipeline 602.

[0083] Preferably, the clean steam generator in this embodiment further includes a steam micro superheater 7; wherein, the steam micro superheater 7 includes: a micro superheater smoke box 701 and a finned serpentine steam superheater tube 702;

[0084] Steam output from the clean steam heat exchanger enters the finned serpentine steam superheater tube 702 and exchanges heat with the flue gas outside the tube to evaporate some of the moisture. Because the steam output from the clean steam heat exchanger contains some water, its dryness is insufficient, affecting the use of steam-using equipment. Steam with insufficient dryness can achieve better heat exchange after multiple bends in the finned tube. The fins outside the tube significantly increase the heat transfer area, allowing for better evaporation of the moisture in the steam inside the tube using the residual heat of the flue gas, achieving a slight superheating effect.

[0085] In the above technical solution, the phase change clean steam generator provided by this utility model has the following beneficial effects:

[0086] The clean steam generator of this invention has the advantages of no scale buildup on the heating surface, long service life, no need for complicated maintenance, and saving materials to reduce costs.

[0087] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A phase change clean steam generator, characterized in that, The clean steam generator includes: The generator body (1) draws air heated by the secondary air preheater (4) through the blower (101) and mixes it with natural gas fuel in the air-fuel mixer (103) to form a premixed combustible gas, which is then burned in the generator body. A clean steam heat exchanger assembly (2) is connected to the primary phase change steam chamber (105) of the generator body (1) via a primary steam pipeline (501) to receive the primary high-temperature steam delivered by the primary phase change steam chamber (105) of the generator body (1). The condensate formed by the primary high-temperature steam in the clean steam heat exchanger assembly (2) after heat exchange is transported back to the generator body (1). The steam micro-superheater (7) connected to the generator body (1) forms a low-temperature flue gas through heat exchange between the flue gas and the saturated steam in the finned serpentine steam superheater (702). This part of the low-temperature flue gas enters the first-stage stainless steel energy saver (3). After being cooled by the first-stage stainless steel energy saver (3), this part of the low-temperature flue gas forms an ultra-low-temperature flue gas. This part of the ultra-low-temperature flue gas enters the second-stage air preheater (4) and is discharged after heat exchange with the combustion air.

2. The phase change clean steam generator according to claim 1, characterized in that, The blower (101) is connected to the secondary air preheater (4) through an air pipeline to draw in the heated combustion air; An air regulating valve (102) is installed between the blower (101) and the air-fuel mixer (103); The generator body (1) includes: A premixed gas chamber (104) connected to the air-fuel mixer (103); A finned water-cooled tube combustor (106) is arranged inside the generator body (1) and close to the premixed gas chamber (104). The premixed gas chamber (104) evenly distributes the premixed gas to the finned water-cooled tube combustor (106) and delivers it to each burner. The generator body (1) is also equipped with a furnace radiant hot water pipe (107) and a convective hot water-fire jacket (109). The upper part of the generator body (1) forms a primary phase change steam chamber (105) and an exhaust smoke box (108). The premixed gas at the burner of the finned water-cooled tube combustion chamber (106) produces a high-temperature, low-NOx flame. After absorbing heat through the furnace radiant hot water pipe (107), the flame is cooled to become high-temperature flue gas. Subsequently, the flue gas is cooled to low-temperature flue gas through heat exchange on the external convective heating surface of the convective hot water-fire jacket (109). Then, this low-temperature flue gas is guided into the convective hot water-fire jacket (109) through the conversion box (110) at the bottom of the generator body (1) and undergoes convective heat transfer to form a secondary low-temperature flue gas, which is then discharged from the exhaust upper smoke box (108).

3. A phase change clean steam generator according to claim 2, characterized in that, Water with a volume of less than 30L injected into the generator body (1) is heated by heat exchange to become primary high-temperature steam, and the primary high-temperature steam is delivered to the clean steam heat exchanger group (2).

4. A phase change clean steam generator according to claim 3, characterized in that, The clean steam heat exchanger group (2) includes multiple sets of shell-and-tube all-stainless steel steam-to-steam heat exchangers. The shell-and-tube all-stainless steel steam-to-steam heat exchanger includes: Stainless steel clean steam chamber (201) located at the top; The stainless steel water supply chamber is located at the bottom; and The stainless steel shell is located in the middle, and stainless steel steam heat exchange tubes (202) are installed inside the stainless steel shell.

5. A phase change clean steam generator according to claim 1, characterized in that, The clean steam generator has a two-stage energy-saving system; The secondary energy-saving system includes a primary stainless steel energy saver (3) and a secondary air preheater (4).

6. A phase change clean steam generator according to claim 5, characterized in that, The first-level stainless steel energy saver (3) includes: The energy-saving device has a stainless steel housing (303), an energy-saving device flue gas inlet (301) located at the upper part of the energy-saving device stainless steel housing (303), and an energy-saving device flue gas outlet (304) located at the lower part of the energy-saving device stainless steel housing (303). Stainless steel heat exchange tubes (302) are installed inside the stainless steel housing (303) of the energy saver; The sub-low temperature flue gas enters from the energy-saving device flue gas inlet (301) of the stainless steel shell (303) of the energy-saving device and exits from the energy-saving device flue gas outlet (304); Water enters from below the stainless steel heat exchange tube (302) and exits from the upper end of the stainless steel heat exchange tube (302) after several turns.

7. A phase change clean steam generator according to claim 6, characterized in that, The secondary air preheater (4) includes: An air preheater housing (401), the upper part of which has a preheater flue gas outlet (404), and the lower part of which has a preheater flue gas inlet (403); and Heat exchange sleeve (402) disposed inside the air preheater housing (401); Flue gas enters the heat exchanger tube (402) through the flue gas inlet (403) of the preheater and is discharged through the flue gas outlet (404) of the preheater; Air enters the air preheater housing (401) from the upper part of the secondary air preheater (4) and is discharged from the lower part of the secondary air preheater (4) and delivered to the inlet of the blower (101).

8. A phase change clean steam generator according to claim 1, characterized in that, The clean steam generator also includes: High-level water supply tank (601); A water supply pump (603) is installed on the high-level water supply tank (601), and the water supply pump (603) is connected to the water supply pump pipeline (602).

9. A phase change clean steam generator according to claim 8, characterized in that, The clean steam generator also includes a steam micro superheater (7); The steam micro superheater (7) includes: Micro superheater smoke box (701) and finned serpentine steam superheater tubes (702); The steam output from the clean steam heat exchanger enters the finned serpentine steam superheater tube (702) and exchanges heat with the flue gas outside the tube to evaporate some of the moisture.

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