A safe and efficient steam boiler system

Abstract

The present invention discloses a safe and efficient steam boiler system, which includes a surface combustion burner, a boiler body, a connecting flue, an economizer, a lower smoke chamber, an atmospheric condenser, and a chimney. The surface combustion burner is connected to the boiler body, the boiler body is connected to the economizer through the connecting flue, the economizer is connected to the atmospheric condenser through the lower smoke chamber, and the atmospheric condenser is connected to the chimney. The present invention has the following advantages and effects: Through the design of the control system and related sensors, the air feed amount is controlled by taking the steam pressure and the heat of the burner head as index signals, so as to achieve the preset mixing ratio of air and natural gas. In addition, through the arrangement design of a number of metal sheets with equal intervals on the burner head, even without dust filtration treatment of the air, it is also possible to avoid the blockage of the air flow gap of the burner head caused by carbon deposition due to incomplete combustion of dust, thus avoiding explosion. Through the three-stage heat exchange design, the temperature as high as more than 2000 °C is reduced to the chimney exhaust temperature of about 55 °C, and the thermal efficiency of the whole system reaches 98%.

Description

Technical Field

[0001] The present invention relates to a boiler, and particularly to a safe and efficient steam boiler system. Background Art

[0002] A boiler for producing steam is called a steam boiler, often simply referred to as a steam furnace. A gas-fired steam boiler is a steam boiler that uses gas combustion to heat and generate steam at a rated pressure. A boiler is a mechanical device that uses the heat energy of fuel or other energy sources to heat water into hot water or steam. The hot water or steam generated in the boiler can directly provide the heat energy required for industrial production and people's livelihood, or can be converted into mechanical energy through a steam power device, or further converted into electrical energy through a generator. Steam boilers are mostly used in thermal power plants, ships, locomotives, and industrial and mining enterprises, and their uses are also very extensive. Electric steam boilers can be used for steam required in the processing processes of industrial products such as textiles, printing and dyeing, papermaking, food, rubber, plastics, chemical engineering, medicine, iron and steel, and metallurgy, and can provide heating, bathing, air conditioning, and domestic hot water for industries such as enterprises, institutions, hotels, schools, catering, and service industries.

[0003] The design of existing gas boiler systems generally focuses on the following aspects:

[0004] (1) Safety is the top priority in all work, and the safety of the gas boiler burner cannot be ignored.

[0005] (2) Energy conservation. The thermal efficiency of ordinary boilers is basically about 90%, and the efficiency is relatively low.

[0006] For current gas boilers, there are defects in the structural design of their combustion heads. Since the air participating in combustion contains dust, some carbon deposits will be generated after long-term combustion. These carbon deposits will block the air flow channels of the existing combustion heads. If not cleaned in time, it will cause the burner to explode. In addition, the current gas boilers have low thermal efficiency, generally only about 90%. These two deficiencies need to be further improved. Summary of the Invention

[0007] The purpose of the present invention is to provide a safe and efficient steam boiler system. The burner used in this steam boiler system solves the potential safety problem of explosion caused by carbon deposit blockage. At the same time, this steam boiler system improves the thermal efficiency, reduces the fuel consumption, and reduces the emissions of nitrogen oxides and particulate matter.

[0008] The above technical object of the present invention is achieved through the following technical solutions: A safe and efficient steam boiler system, including a surface combustion burner, a boiler body, a connecting flue, an economizer, a lower smoke chamber, an atmospheric condenser, and a chimney. The surface combustion burner is connected to the boiler body. The boiler body is connected to the economizer through the connecting flue. The economizer is connected to the atmospheric condenser through the lower smoke chamber. The atmospheric condenser is connected to the chimney.

[0009] The surface combustion burner includes a combustion head, a mixer, a manual regulating valve, a valve group, a draft switch, a blower, an ignition device, and a control system. The combustion head is connected to one end of the mixer through a gas mixing pipeline A. The lower part of the mixer is connected to the valve group through a natural gas pipeline B. The other end of the mixer is connected to the blower through an air pipeline C. The manual regulating valve is arranged on the natural gas pipeline B. The draft switch is arranged on the air pipeline C. The ignition device is close to the combustion head and is on the parallel plane of the combustion head. The control system is used to control the mixer, the valve group, the draft switch, the blower, and the ignition device.

[0010] The combustion head consists of a combustion mask, water-cooled pipes, and a combustion surface. The combustion mask is communicated with the mixer through a gas mixing pipeline A. There are gaps between the water-cooled pipes. The water-cooled pipes are arranged side by side through the combustion mask. Both ends of the water-cooled pipes are respectively connected to water pipes to form a circulating water path. The combustion surface is rectangular and is formed by arranging a number of metal sheets with equal intervals. The gaps left between the metal sheets serve as channels for the mixed gas to flow through. The ignition device is close to the combustion surface.

[0011] A further setting of the present invention is that: The mixer is provided with a vortex wheel and a mixing chamber. The vortex wheel is rotationally matched with the air inlet end of the mixing chamber relatively. The mixing chamber is in a cylindrical conical shape. A number of air outlet holes are opened on the cylindrical wall of the mixing chamber. The mixing chamber is also connected to the manual regulating valve and the valve group in sequence through the natural gas pipeline B. The valve group is connected to the natural gas supply end through the natural gas pipeline B.

[0012] A further setting of the present invention is that: The vortex wheel is provided with a number of metal fan blades. The metal fan blades are distributed 360 degrees along the vortex wheel in a circle. All the metal fan blades are not in the same plane respectively.

[0013] The vortex wheel is driven so that natural gas and air are sent into the mixing chamber. Under the vortex air flow formed by the vortex wheel, natural gas and air are fully mixed and then discharged through the air outlet holes and reach the combustion head through the gas mixing pipeline A.

[0014] A further setting of the present invention is that: The economizer is connected to a water inlet valve through a pipeline near the bottom. The water inlet valve is connected to a circulating water pump through a pipeline. The circulating water pump is connected to a heat preservation water tank. The heat preservation water tank is connected to the economizer to form a water cycle.

[0015] A further setting of the present invention is that: a water flow pipeline W flowing from the economizer to the boiler body is provided between the boiler body and the economizer. A water level sensor is provided on the boiler body at the connection side of the water flow pipeline W and the boiler body. A pressure valve, a safety valve, and a vent valve are provided at the top of the boiler body. The economizer is further connected to a water pump, the water pump is connected to a heat preservation water tank, and the heat preservation water tank, the water pump, the economizer, the water flow pipeline W, and the boiler body form a water channel.

[0016] A further setting of the present invention is that: the atmospheric condenser is provided with an S-shaped condensation pipeline with the same-side inlet and outlet.

[0017] A further setting of the present invention is that: a working method of the steam boiler system is also provided, including the following steps:

[0018] 1) Start the water circulation: Open the inlet valve and the circulation water pump to enable water circulation among the heat preservation water tank, the circulation water pump, and the economizer.

[0019] 2) Combustion burner steam pressure acquisition stage: Collect the steam pressure signal and transmit it to the control system. The control system issues an instruction to control the blower to achieve the control of the air feed volume. The air enters the mixer through the air pipeline C.

[0020] 3) Blower air feed and natural gas feed stage: Turn on the blower to feed air, adjust the air pressure through the air pressure switch, transmit the action signal of the air pressure switch and the flow signal collected by the flowmeter to the control system. Open the manual regulating valve, and the control system and the valve group with a set air-fuel ratio realize the control of the natural gas feed volume. While the control system adjusts the opening of the valve group to control the flow, it also receives the pressure signal real-time feedback through the pressure sensor built in the valve group to achieve the preset air and natural gas intake ratio and matching pressure. The natural gas enters the mixer through the natural gas pipeline B.

[0021] 4) Mixer mixing stage: The air from the blower enters the mixer through the air pipeline C, while the natural gas enters the mixer from the pipeline B below the mixer. The air and natural gas are mixed in the mixer. Due to the continuous influx of air and natural gas, the mixed gas is discharged from the other end of the mixer and flows into the burner head through the gas mixing pipeline A.

[0022] 5) Ignition device ignition stage: When the valve group is opened, at this time, the ignition device is signaled by the control system to synchronously ignite, so that the ignition action is not later than the time when the natural gas flows out of the burner head.

[0023] A mixed gas composed of natural gas and air in a certain proportion flows into the burner head, and this mixed gas is ignited. The heat generated by the combustion of the mixed gas is collected and fed back to the control system. If the heat value exceeds the demand, the control system reduces the air feed volume of the blower, thereby reducing the feed volume of natural gas. If the heat value does not meet the demand, the control system increases the air feed volume of the blower. Without changing the controllable ratio of the pre-mixed air-fuel ratio, when the feed volume of natural gas increases, the combustion heat of the mixed gas increases.

[0024] 6) Stage of high-temperature flue gas entering the boiler body: After ignition in step 5), the high-temperature flue gas reaching 2000 - 2200 °C from the combustion of gas enters the boiler body for the first-stage heat exchange.

[0025] 7) Stage of flue gas entering the economizer: The flue gas cooled to 255 - 265 °C after step 6) enters the economizer through the connecting flue. The water circulation composed of a heat preservation water tank, a circulating water pump, an inlet valve, and the economizer exchanges heat with the flue gas to form the second-stage heat exchange, further reducing the flue gas temperature to 75 - 85 °C.

[0026] 8) Stage of flue gas entering the atmospheric condenser: The flue gas after step 7) enters the atmospheric condenser through the lower smoke chamber. The atmospheric condenser continues to cool the flue gas at 75 - 85 °C to form the third-stage heat exchange. Finally, the flue gas temperature drops to 50 - 60 °C, which is lower than the designed exhaust temperature, and flows out of the chimney to the next device.

[0027] A further setting of the present invention is that: the particulate matter emission concentration of the flue gas < 5 mg / Nm 3 , the sulfur dioxide concentration < 10 mg / Nm 3 , the nitrogen oxide concentration < 25 mg / Nm 3 , and the Ringelmann blackness ≤ 1.

[0028] In summary, the present invention has the following beneficial effects: Through the design of the control system and related sensors, it is realized to control the air feed volume with the steam pressure and the heat of the burner head as the index signals. Then, the opening degree of the valve group is controlled by the control system through the air feed volume index signal to achieve the ratio of natural gas, reaching the preset mixing ratio of air and natural gas. In addition, through the design of arranging a number of equally spaced metal sheets on the burner head, without additional treatment such as dust filtration of air, it is also possible to avoid the blockage of the air flow gap of the burner head caused by carbon deposition due to incomplete combustion of dust, preventing dangerous situations such as explosion from occurring. Through the three-stage heat exchange design, the temperature as high as 2000 - 2200 °C is reduced to the chimney exhaust temperature of 50 - 60 °C, and the thermal efficiency of the entire system reaches 98%. Brief Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of a safe and efficient steam boiler system;

[0030] Figure 2 is Figure 1 Schematic diagram of the structure of a surface combustion burner;

[0031] Figure 3 is Figure 2 Schematic diagram of the structure of the combustion head;

[0032] Figure 4 is Figure 3 Schematic diagram of the combustion surface structure of the combustion head;

[0033] Figure 5 is Figure 2 Schematic diagram of the sectional structure of the mixer;

[0034] Figure 6 is a side view of a safe and efficient steam boiler system;

[0035] Figure 7 is a top view of a safe and efficient steam boiler system;

[0036] Reference numerals: 1, surface combustion burner; 2, boiler body; 3, connecting flue; 4, economizer; 5, lower smoke chamber; 6, atmospheric condenser; 7, chimney; 8, inlet valve; 9, water level sensor; 11, combustion head; 12, mixer; 13, manual regulating valve; 14, valve group; 15, air pressure switch; 16, blower; 61, S-shaped condensation pipe; 111, combustion mask; 112, water-cooled pipe; 113, combustion surface; 121, vortex wheel; 122, mixing chamber; 1131, metal sheet; 1132, gap; 1211, metal fan blade; 1221, air outlet hole. Detailed implementation manners

[0037] The present invention will be further described in detail below with reference to the accompanying drawings:

[0038] As Figures 1-7 shown, a safe and efficient steam boiler system includes a surface combustion burner 1, a boiler body 2, a connecting flue 3, an economizer 4, a lower smoke chamber 5, an atmospheric condenser 6, and a chimney 7. The surface combustion burner 1 is connected to the boiler body 2, the boiler body 2 is connected to the economizer 4 through the connecting flue 3, the economizer 4 is connected to the atmospheric condenser 6 through the lower smoke chamber 5, and the atmospheric condenser 6 is connected to the chimney 7.

[0039] The surface burner 1 further includes a combustion head 11, a mixer 12, a manual regulating valve 13, a valve group 14, a wind pressure switch 15, a blower 16, an ignition device, and a control system. The combustion head 11 is connected to one end of the mixer 12 through a gas mixing pipeline A. The lower part of the mixer 12 is connected to the valve group 14 through a natural gas pipeline B. The other end of the mixer 12 is connected to the blower 16 through an air pipeline C. The manual regulating valve 13 is arranged on the natural gas pipeline B, and the wind pressure switch 15 is arranged on the air pipeline C. The ignition device is close to the combustion head 11 and is on the parallel plane of the combustion head 11. The control system controls the mixer 12, the valve group 14, the wind pressure switch 15, the blower 16, and the ignition device through signals.

[0040] The combustion head 11 is composed of a combustion mask 111, water-cooled pipes 112, and a combustion surface 113. The combustion mask 111 communicates with the mixer 12 through a gas mixing pipeline A. There are gaps between the water-cooled pipes 112. The water-cooled pipes 112 are arranged side by side and pass through the combustion mask 111. Both ends of the water-cooled pipes 112 are connected to water pipes to form a circulating water path. The combustion surface 113 is rectangular and is formed by arranging a number of metal sheets 1131 with equal intervals. The gaps 1132 left between the metal sheets 1131 serve as channels for the mixed gas to flow through. The ignition device is close to the combustion surface 113. When the blower 16 sends in a certain amount of air, the valve group 14 makes an opening action with a corresponding opening according to the air volume, and sends in natural gas in a certain proportion to the air. The air and natural gas are evenly mixed in the mixer and then sent into the combustion head 11 through the gas mixing pipeline A. The evenly mixed air and natural gas flow through the gaps between the water-cooled pipes 112 until they reach the combustion surface 113 formed by a number of metal sheets 1131 with equal intervals. Compared with the traditional mesh design, on the one hand, this combustion surface can avoid explosion caused by blockage of fine carbon deposits during combustion, threatening personal safety. On the other hand, it can improve the working efficiency and service life of the burner.

[0041] In this embodiment, a vortex wheel 121 and a mixing chamber 122 are arranged inside the mixer 12. The vortex wheel 121 is rotationally matched with the air inlet end of the mixing chamber 122 relatively. The mixing chamber 122 is in a cylindrical cone shape. A number of air outlet holes 1221 are opened on the cylindrical wall of the mixing chamber 122. The mixing chamber 122 is also connected to the manual regulating valve 13 and the valve group 14 in sequence through the natural gas pipeline B. The valve group 14 is connected to the natural gas supply end through the natural gas pipeline B.

[0042] In this embodiment, a number of metal fan blades 1211 are arranged on the vortex wheel 121. The metal fan blades 1211 are distributed 360 degrees along one circle of the vortex wheel 121, and all the metal fan blades 1211 are not in the same plane.

[0043] The driving scroll wheel 121 causes natural gas and air to be fed into the mixing chamber 122. Under the swirling air flow formed by the scroll wheel 121, the natural gas and air are fully mixed and then discharged from the air outlet 1221 and pass through the mixing gas pipeline A until the burner 11.

[0044] In this embodiment, the control system is used to control the mixer 12, the valve group 14, the air pressure switch 15, the blower 16, and the ignition device. Through the design of the control system and related sensors in this embodiment, the air feed amount is controlled with the steam pressure and the heat of the burner as the index signals. Then, the opening degree of the valve group is controlled by the control system through the air feed amount index signal to realize the ratio of natural gas, so as to achieve the preset mixing ratio of air and natural gas.

[0045] In this embodiment, the economizer 4 is connected to the water inlet valve 8 through a pipeline near the bottom. The water inlet valve 8 is connected to a circulating water pump through a pipeline. The circulating water pump is connected to a heat preservation water tank, and the heat preservation water tank is connected to the economizer 4 to form a water cycle.

[0046] In this embodiment, there is a water flow pipeline W from the economizer 4 to the boiler body 2 between the boiler body 2 and the economizer 4. A water level sensor 9 is provided on the boiler body 2 at the connection side of the water flow pipeline W and the boiler body 2. A pressure valve, a safety valve, and a vent valve are provided at the top of the boiler body 2. The economizer 4 is also connected to another water pump, and the water pump is connected to the heat preservation water tank. The heat preservation water tank, the water pump, the economizer 4, the water flow pipeline W, and the boiler body 2 form a water channel.

[0047] In this embodiment, the atmospheric condenser 6 is provided with an S-shaped condensation pipeline 61 with the same-side inlet and outlet.

[0048] In this embodiment, a method for using a safe and efficient steam boiler system is as follows:

[0049] 1) Start the water cycle: Open the water inlet valve 8 and turn on the circulating water pump to make the heat preservation water tank, the circulating water pump, and the economizer 4 perform a water cycle;

[0050] 2) Combustor steam pressure acquisition stage: Collect the steam pressure and transmit the pressure signal to the control system. The control system issues an instruction to control the blower 16 to realize the control of the air feed amount. The air enters the mixer 12 through the air pipeline C.

[0051] 3) Blower air feeding and natural gas feeding stage: The blower 16 feeds a certain amount of air, adjusts the air pressure through the air pressure switch 15, transmits the action signal of the air pressure switch 15 and the flow signal collected by the flowmeter to the control system, opens the manual regulating valve 13, and the control system and the valve group 14 with the set air-fuel ratio realize the control of the natural gas feeding amount. While the control system adjusts the opening of the valve group 14 to control the flow, it also receives the pressure signal real-time feedback through the pressure sensor built in the valve group 14 to achieve the preset air and natural gas intake ratio and matching pressure. The natural gas enters the mixer 12 through the natural gas pipeline B;

[0052] 4) Mixer mixing stage: The air coming from the blower 16 enters the mixer 12 from the end of the mixer 12 where the vortex wheel 121 is provided. Under the action of the rotation of the metal fan blade 1211, the air is brought into the mixing chamber 122, and the natural gas enters the mixing chamber 122 from the pipeline B below the mixing chamber 122. The air and natural gas are mixed in the mixing chamber 122. Due to the continuous influx of air and natural gas, the mixed gas flows out from the air holes 1221 opened in the mixing chamber 122, and after being discharged from the other end of the mixer 12, it flows into the burner head 11 through the gas mixing pipeline A;

[0053] 5) Ignition device ignition stage: When the valve group 14 is opened, at this time, the ignition device is signaled to synchronously ignite by the control system, so that the ignition action is not later than the time when the natural gas flows out from the burner head 11.

[0054] A mixture of natural gas and air in a certain proportion flows into the burner head 11, and this mixture is ignited. The heat generated by the combustion of the mixture is collected and fed back to the control system; if the heat value exceeds the demand, the control system reduces the air feeding amount of the blower 16, thereby reducing the natural gas feeding amount; if the heat value does not reach the demand, the control system increases the air feeding amount of the blower 16. Under the condition that the pre-mixed air-fuel ratio remains controllable, the natural gas feeding amount increases, and the combustion heat of the mixture increases;

[0055] 6) High-temperature flue gas enters the boiler body stage: After ignition in step 5), the high-temperature flue gas with a temperature of 2000 - 2200 °C generated by the combustion of the gas will enter the boiler body 2. The water channel formed by the heat preservation water tank, water pump, economizer 4, water flow pipeline W, and boiler body 2 is opened, and the high-temperature flue gas exchanges heat with the circulating water to form the first-stage heat exchange;

[0056] 7) Flue gas enters the economizer stage: After step 6), the flue gas cooled to about 255 - 265 °C enters the economizer 4 through the connecting flue 3. The water circulation formed by the heat preservation water tank, circulating water pump, inlet valve 8, and economizer 4 constitutes the second-stage heat exchange, further reducing the flue gas temperature to 75 - 85 °C;

[0057] 8) Flue gas enters the atmospheric condenser stage: The flue gas after step 7) enters the atmospheric condenser 6 through the lower flue chamber 5. Before the flue gas enters, the atmospheric condenser 6 first passes cold water through the S-shaped condensation pipeline 61. The cold water circulating in the S shape further cools the flue gas at 75 - 85 °C, forming the third-stage heat exchange. Finally, the temperature of the flue gas drops to 50 - 60 °C, which is lower than the designed flue gas discharge temperature, and flows out from the chimney 7 to the next device. Through the three-stage heat exchange design in this embodiment, the temperature of the flue gas, which was originally as high as 2000 - 2200 °C, is reduced to the chimney discharge temperature of 50 - 60 °C, and the thermal efficiency of the entire system reaches 98%.

[0058] In this embodiment, the particulate matter emission concentration of the flue gas < 5 mg / Nm 3 , the sulfur dioxide concentration < 10 mg / Nm 3 , the nitrogen oxide concentration < 25 mg / Nm 3 , and the Ringelmann blackness ≤ 1; effectively reducing air pollution.

[0059] The specific embodiments are only explanations of the present invention and not limitations thereof. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A working method of a safe and efficient steam boiler system, characterized in that, The steam boiler system includes a surface combustion burner (1), a boiler body (2), a connecting flue (3), an economizer (4), a lower smoke chamber (5), an atmospheric condenser (6), and a chimney (7). The surface combustion burner (1) is connected to the boiler body (2). The boiler body (2) is connected to the economizer (4) through the connecting flue (3). The economizer (4) is connected to the atmospheric condenser (6) through the lower smoke chamber (5). The atmospheric condenser (6) is connected to the chimney (7). The surface combustion burner (1) includes a combustion head (11), a mixer (12), a manual regulating valve (13), a valve group (14), a draft switch (15), a blower (16), an ignition device, and a control system. The combustion head (11) is connected to one end of the mixer (12) through a gas mixing pipeline A. The lower part of the mixer (12) is connected to the valve group (14) through a natural gas pipeline B. The other end of the mixer (12) is connected to the blower (16) through an air pipeline C. The manual regulating valve (13) is arranged on the natural gas pipeline B. The draft switch (15) is arranged on the air pipeline C. The ignition device is close to the combustion head (11) and is in a plane parallel to the combustion head (11). The control system is used to control the mixer (12), the valve group (14), the draft switch (15), the blower (16), and the ignition device. The combustion head (11) is composed of a combustion mask (111), water-cooled pipes (112), and a combustion surface (113). The combustion mask (111) communicates with the mixer (12) through a gas mixing pipeline A. There are gaps between the water-cooled pipes (112). The water-cooled pipes (112) pass through the combustion mask (111) side by side. Both ends of the water-cooled pipes (112) are respectively connected to water pipes to form a circulating water path. The combustion surface (113) is rectangular and is formed by arranging a number of metal sheets (1131) with equal intervals. The gaps (1132) left between the metal sheets (1131) serve as channels for the mixed gas to flow through. The ignition device is close to the combustion surface (113). The mixer (12) is internally provided with a vortex wheel (121) and a mixing chamber (122). The vortex wheel (121) is rotationally matched with the air inlet end of the mixing chamber (122). The mixing chamber (122) is in a cylindrical cone shape. A number of air outlet holes (1221) are opened on the cylindrical wall of the mixing chamber (122). The mixing chamber (122) is also connected to the manual regulating valve (13) and the valve group (14) in sequence through the natural gas pipeline B. The valve group (14) is connected to the natural gas supply end through the natural gas pipeline B. A number of metal fan blades (1211) are provided on the vortex wheel (121). The metal fan blades (1211) are distributed at 360 degrees along one circle of the vortex wheel (121). All the metal fan blades (1211) are not in the same plane. The driving scroll wheel (121) causes natural gas and air to be fed into the mixing chamber (122). Under the swirling air flow formed by the scroll wheel (121), the natural gas and air are fully mixed and then discharged through the air outlet hole (1221) and pass through the mixing gas pipeline A until they reach the burner head (11). Near the bottom, the energy saver (4) is connected to the water inlet valve (8) through a pipeline. The water inlet valve (8) is connected to a circulating water pump through a pipeline. The circulating water pump is connected to a heat preservation water tank, and the heat preservation water tank is connected to the energy saver (4) to form a water cycle. The working method of the steam boiler system includes the following steps: 1) Start the water cycle: Open the water inlet valve (8) and the circulating water pump to enable the heat preservation water tank, the circulating water pump, and the energy saver (4) to perform a water cycle. 2) Burner steam pressure acquisition stage: Collect the steam pressure signal and transmit it to the control system. The control system issues an instruction to control the blower (16) to achieve the control of the air feed volume. The air enters the mixer (12) through the air pipeline C. 3) Blower air feed and natural gas feed stage: Turn on the blower (16) to feed air, adjust the air pressure through the air pressure switch (15), transmit the action signal of the air pressure switch (15) and the flow signal collected by the flow meter to the control system, open the manual regulating valve (13), and the control system and the valve group (14) with a set air-fuel ratio achieve the control of the natural gas feed volume. While the control system adjusts the opening of the valve group (14) to control the flow rate, it also receives the pressure signal real-time feedback through the pressure sensor built in the valve group (14) to achieve the preset air and natural gas feed volume ratio and matching pressure. The natural gas enters the mixer (12) through the natural gas pipeline B. 4) Mixer mixing stage: The air coming from the blower (16) enters the mixer (12) from the air pipeline C, while the natural gas enters the mixer (12) from the pipeline B below the mixer (12). The air and natural gas are mixed in the mixer (12). Due to the continuous influx of air and natural gas, the mixed gas is discharged from the other end of the mixer (12) and flows into the burner head (11) through the mixing gas pipeline A. 5) Ignition device ignition stage: When the valve group (14) is opened, at this time, the ignition device is signaled by the control system to synchronously ignite, so that the ignition action is not later than the time when the natural gas flows out of the burner head (11). A mixture of natural gas and air in a certain proportion flows into the burner head (11). This mixed gas flow is ignited, and the heat generated by the combustion of the mixed gas is collected and fed back to the control system. If the heat value exceeds the demand, the control system reduces the air feed volume of the blower (16), thereby reducing the natural gas feed volume. If the heat value does not reach the demand, the control system increases the air feed volume of the blower (16). Without changing the controllable proportion of the premixed air-fuel ratio, the natural gas feed volume increases, and the combustion heat of the mixed gas increases. 6) High-temperature flue gas enters the boiler body stage: After ignition in step 5), the high-temperature flue gas with a temperature of 2000 - 2200 °C after gas combustion enters the boiler body (2) for the first-stage heat exchange. 7) Flue gas enters the economizer stage: The flue gas, which has been reduced to 255 - 265 °C after step 6), enters the economizer (4) through the connecting flue (3). The water circulation composed of the heat preservation water tank, the circulating water pump, the water inlet valve (8), and the economizer (4) exchanges heat with the flue gas to form the second-stage heat exchange, further reducing the flue gas temperature to 75 - 85 °C; 8) Flue gas enters the atmospheric condenser stage: The flue gas after step 7) enters the atmospheric condenser (6) through the lower smoke chamber (5). The atmospheric condenser (6) continues to cool the flue gas at 75 - 85 °C to form the third-stage heat exchange. Finally, the flue gas temperature drops to 50 - 60 °C, which is lower than the designed flue gas discharge temperature, and flows out from the chimney (7) to the next equipment.

2. The working method of the steam boiler system according to claim 1, characterized in that: A water flow pipeline W flowing from the economizer (4) to the boiler body (2) is provided between the boiler body (2) and the economizer (4). A water level sensor (9) is provided on the boiler body (2) on the side where the water flow pipeline W is connected to the boiler body (2). A pressure valve, a safety valve, and a vent valve are provided at the top of the boiler body (2). The economizer (4) is also connected to a water pump, and the water pump is connected to the heat preservation water tank. The heat preservation water tank, the water pump, the economizer (4), the water flow pipeline W, and the boiler body (2) form a water channel.

3. The working method of the steam boiler system according to claim 1, characterized in that: The atmospheric condenser (6) is provided with an S-shaped condensation pipeline (61) with the same-side inlet and outlet.

4. The working method of the steam boiler system according to claim 1, characterized in that: The particulate matter emission concentration of the flue gas is less than 5mg / Nm 3 , sulfur dioxide concentration <10mg / Nm 3 , nitrogen oxide concentration <25mg / Nm 3 , Ringelmann blackness ≤1.

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