A saturated dual-purpose steam boiler and its flue structure

Abstract

The present invention relates to the technical field of boilers, and particularly relates to a saturated dual-purpose steam boiler and its flue structure, including: a first boiler for burning fuel to generate flue gas and converting liquid water into steam through heat exchange; a second boiler for burning fuel to heat saturated steam into superheated steam; a smoke outlet for discharging the flue gas generated by the boiler; a connecting flue for introducing the flue gas of the second boiler into the first boiler; a steam-water separator for separating water droplets in the steam to obtain purer and drier saturated steam; a drainage module for discharging the condensed water separated by the steam-water separator and preventing steam leakage at the same time; a water supply module for supplying water to the first boiler and the second boiler; and an overpressure discharge module for discharging superheated steam to reduce the pressure in the second boiler. The beneficial effects of the present invention are: it can produce saturated steam and superheated steam under different working conditions, can prevent the direct impact of flue gas from causing local eddy currents, shares a smoke outlet, and improves the applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of boilers, and particularly to a saturated dual-purpose steam boiler and its flue structure. Background Art

[0002] Boilers play a key role in industrial production, capable of generating saturated steam and superheated steam to meet different production requirements. Water is heated in the boiler, and the thermal motion of water molecules intensifies. When reaching a certain temperature, water begins to vaporize to form steam. The saturated steam enters the superheater and further absorbs heat in the high-temperature flue gas area, and the temperature continues to rise and exceeds the saturated temperature at this pressure, then it becomes superheated steam. Superheated steam has unique advantages in work and heat transfer efficiency and is more suitable for industrial processes with high requirements for steam quality.

[0003] In the prior art, saturated steam or superheated steam is usually produced by different boiler equipment respectively. In scenarios where both saturated steam and superheated steam are required simultaneously, a single boiler equipment cannot meet the usage requirements. For some boilers that can produce saturated steam and superheated steam simultaneously, the flue gas in the boiler may cause local eddies due to head-on collision, resulting in unstable back pressure. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present application proposes a saturated dual-purpose steam boiler and its flue structure, which can produce saturated steam and superheated steam under different working conditions, can prevent local eddies caused by direct head-on collision of flue gas, resulting in unstable back pressure, share a single flue outlet, and improve applicability.

[0005] The following is the technical solution of the present invention. A saturated dual-purpose steam boiler includes:

[0006] A first boiler for burning fuel to generate flue gas and converting liquid water into steam through heat exchange;

[0007] A second boiler for burning fuel to heat saturated steam into superheated steam;

[0008] A flue outlet for discharging the flue gas generated by the boiler, connected to the first boiler;

[0009] A connecting flue for guiding the flue gas of the second boiler into the first boiler, connecting the first boiler and the second boiler;

[0010] A steam-water separator for separating water droplets in the steam to obtain purer and drier saturated steam, connected to the first boiler and the second boiler;

[0011] A drain module for discharging the condensed water separated by the steam-water separator and preventing steam leakage at the same time, connected to the steam-water separator;

[0012] Saturated steam outlet, used to discharge saturated steam, connecting the steam-water separator and the second boiler;

[0013] Feed water module, used to convey feed water to the first boiler and the second boiler, connecting the first boiler and the second boiler;

[0014] Overpressure discharge module, used to discharge superheated steam to reduce the pressure in the second boiler, connecting the second boiler;

[0015] Superheated steam outlet, used to discharge superheated steam, connecting the second boiler.

[0016] As a preferred solution of the present invention, it further includes:

[0017] The first valve, used to control the on-off of the saturated steam and the saturated steam outlet, is arranged in the pipeline between the saturated steam outlet and the steam-water separator;

[0018] The second valve, used to control the on-off of the saturated steam and the second boiler, is arranged in the pipeline between the steam-water separator and the second boiler;

[0019] The third valve, used to control the on-off of the superheated steam and the regulating valve, is arranged in the pipeline between the second boiler and the superheated steam outlet;

[0020] The fourth valve, used to control the discharge of superheated steam, is arranged in the pipeline between the third valve and the superheated steam outlet.

[0021] As a preferred solution of the present invention, the drain module is provided with a drain valve, and the drain valve automatically opens to discharge condensate water. The expression is as follows:

[0022]

[0023]

[0024] In the above formula, is the drainage volume of the drain valve, is the flow coefficient of the drain valve, is the pressure difference between the inlet and outlet of the drain valve, is the density of the condensate water, and are empirical coefficients, is the temperature difference between the steam and the condensate water; is 0.9, is 0.01.

[0025] A flue structure of a saturated dual-purpose steam boiler, including:

[0026] The first combustion chamber, used to burn fuel to generate flue gas, is arranged at the bottom of the first boiler;

[0027] The first heating surface, which is used to heat water to evaporate and form saturated steam, is arranged around the first combustion chamber in the furnace and above it;

[0028] The first smoke deflector, which is used to deflect the flue gas of the first combustion chamber, is arranged above the first heating surface;

[0029] The throttle hole, which is used to prevent the backpressure fluctuation caused by the mixing of the flue gas of the second boiler into the first boiler and ensure the normal combustion of the first boiler, is arranged at the end of the first smoke deflector;

[0030] The second smoke deflector, which is used to deflect the mixed flue gas of the first combustion chamber and the second combustion chamber, is arranged below the second heating surface;

[0031] The second heating surface, which is used to heat water to evaporate and form saturated steam, is arranged below the smoke outlet;

[0032] The connecting flue butterfly valve, which is used to control the flue gas flow of the second boiler entering the first boiler, is arranged in the connecting flue;

[0033] The second combustion chamber, which is used to burn fuel to generate flue gas, is arranged at the bottom of the second boiler;

[0034] The third heating surface, which is used to heat saturated steam to form superheated steam, is arranged around the second combustion chamber in the furnace and above it;

[0035] The energy-saving section, which is used to enhance the heat exchange efficiency, is arranged above the third heating surface.

[0036] As a preferred embodiment of the present invention, the height of the first smoke deflector is greater than or equal to the height of the connecting flue.

[0037] As a preferred embodiment of the present invention, the width of the smoke passage formed by the first smoke deflector gradually decreases along the flue gas passage of the first boiler towards the second heating surface.

[0038] As a preferred embodiment of the present invention, the first heating surface, the second heating surface and the third heating surface are designed in a multi-segment bending type or a spiral shape.

[0039] As a preferred embodiment of the present invention, the area of the first heating surface is greater than the area of the third heating surface, and the area of the third heating surface is greater than or equal to the area of the second heating surface.

[0040] As a preferred embodiment of the present invention, the flue length of the connecting flue is not greater than the height of the second boiler, and the inner diameter of the connecting flue is less than half of the second boiler.

[0041] Advantages of the present invention: It can produce saturated steam and superheated steam under different working conditions. When producing superheated steam, an external independent steam superheater is adopted, and through the design of the connecting flue, the second boiler shares the flue gas outlet of the first boiler, and it can prevent the direct impact of flue gas from causing local eddy currents and unstable back pressure, reducing the cost of the boiler system and the cost of flue gas treatment and maintenance. At the same time, it can effectively utilize the waste heat of the flue gas of the second boiler, improving the applicability and energy utilization rate. Brief Description of the Drawings

[0042] Figure 1 Schematic diagram of the saturated dual-purpose steam boiler of the present invention;

[0043] Figure 2 Operation control diagram of the saturated dual-purpose steam boiler of the present invention;

[0044] Figure 3 Flue duct structure diagram of the saturated dual-purpose steam boiler of the present invention;

[0045] In the figure: 1. First boiler; 2. Second boiler; 3. Connecting flue; 4. Flue gas outlet; 5. Steam-water separator; 6. Drainage module; 7. Feed water module; 8. Saturated steam outlet; 9. Overpressure discharge module; 10. Superheated steam outlet; 11. First valve; 12. Second valve; 13. Third valve; 14. Fourth valve; 15. First combustion chamber; 16. First heating surface; 17. First smoke guide plate; 18. Second smoke guide plate; 19. Throttle hole; 20. Second heating surface; 21. Connecting flue butterfly valve; 22. Second combustion chamber; 23. Third heating surface; 24. Energy-saving section. Detailed Embodiment

[0046] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0047] Embodiment 1:

[0048] As Figure 1 and Figure 2 shown, a saturated dual-purpose steam boiler includes:

[0049] The first boiler 1 is used for burning fuel to generate flue gas, converting liquid water into steam through heat exchange, and connecting to the steam-water separator 5, the flue gas outlet 4, and the connecting flue 3;

[0050] The flue gas outlet 4 is used for discharging the flue gas generated by the boiler and connecting to the first boiler 1;

[0051] A connecting flue 3 for introducing the flue gas of the second boiler 2 into the first boiler 1 to connect the first boiler 1 and the second boiler 2;

[0052] A steam-water separator 5 for separating water droplets in the steam to obtain purer and drier saturated steam, connecting the first boiler 1, the saturated steam outlet 8 and the second boiler 2;

[0053] A drain module 6 for discharging the condensed water separated by the steam-water separator 5 and preventing steam leakage, connecting the steam-water separator 5;

[0054] A first valve 11 for controlling the on-off of the saturated steam and the saturated steam outlet 8, arranged in the pipeline between the saturated steam outlet 8 and the steam-water separator 5;

[0055] A saturated steam outlet 8 for discharging saturated steam, connecting the steam-water separator 5 and the second boiler 2;

[0056] A second valve 12 for controlling the on-off of the saturated steam and the second boiler 2, arranged in the pipeline between the steam-water separator 5 and the second boiler 2;

[0057] A second boiler 2 for burning fuel to heat the saturated steam into superheated steam, connecting the connecting flue 3, the feed water module 7, the superheated steam outlet 10 and the overpressure discharge module 9;

[0058] A feed water module 7 for conveying feed water to the first boiler 1 and the second boiler 2, connecting the first boiler 1 and the second boiler 2;

[0059] An overpressure discharge module 9 for discharging superheated steam to reduce the pressure in the second boiler 2, connecting the second boiler 2;

[0060] A third valve 13 for controlling the on-off of the superheated steam and the fourth valve 14, arranged in the pipeline between the second boiler 2 and the superheated steam outlet 10;

[0061] A fourth valve 14 for controlling the discharge of superheated steam, arranged in the pipeline between the third valve 13 and the superheated steam outlet 10;

[0062] A superheated steam outlet 10 for discharging superheated steam, connecting the second boiler 2.

[0063] In this embodiment, the first boiler 1 is provided with a steam generator. The steam generator burns fuel to generate high-temperature flue gas. The high-temperature flue gas generated by the fuel combustion has a large amount of heat energy, and this heat is transferred to the water in the steam generator through heat exchangers, radiation, convection, etc. When the water absorbs enough heat and its temperature rises to the boiling point, water molecules change from the liquid state to the gaseous state to form steam. When the first valve 11 is opened and the second valve 12, the third valve 13, and the fourth valve 14 are closed, the saturated steam separated by the steam-water separator 5 is sent out through the saturated steam outlet 8.

[0064] In this embodiment, the smoke outlet 4 discharges the flue gas of the first boiler 1 and the second boiler 2. When the first boiler 1 and the second boiler 2 are operating, fuel burns in the furnace to generate a large amount of combustion waste gas, which contains components such as carbon dioxide, water vapor, sulfur dioxide, nitrogen oxides, and unburned particulate matter. The main function of the smoke outlet 4 is to smoothly discharge the waste gas generated by combustion from the boiler system, so that the combustion process in the boiler can proceed continuously and stably. The smoke outlet 4 adjusts the pressure in the furnace by controlling the discharge amount of the waste gas to keep it within a suitable range. When the pressure in the furnace is too high, the discharge amount of the waste gas is increased through the smoke outlet 4 to reduce the furnace pressure; when the pressure is too low, the discharge amount of the waste gas is appropriately reduced to maintain the pressure stability and avoid problems such as flame ejection and air leakage caused by abnormal furnace pressure, ensuring the safety and stability of the boiler operation. At the same time, the second boiler 2 shares the smoke outlet 4 of the first boiler 1, which is convenient for the centralized discharge and treatment of flue gas. It can not only simplify the structure of the boiler system, but also reduce the cost of the boiler system and the cost of flue gas treatment and maintenance.

[0065] In this embodiment, the connecting flue 3 guides the flue gas of the second boiler 2 into the first boiler 1. The design of the connecting flue 3 enables the second boiler 2 to share the smoke outlet 4 of the first boiler 1, reducing the cost of the boiler system and the cost of flue gas treatment and maintenance. At the same time, compared with directly discharging the flue gas of the second boiler 2, the flue gas of the second boiler 2 is discharged into the first boiler 1 and mixed with the flue gas of the first boiler 1, which can effectively utilize the waste heat of the flue gas of the second boiler 2 and improve the energy utilization rate.

[0066] In this embodiment, the steam-water separator 5 separates the water droplets in the steam to obtain purer and drier saturated steam. The steam generated by the steam generator of the first boiler 1 often carries some moisture. The steam-water separator 5 can separate the entrained moisture in the steam, making the steam drier and purer, reducing the water content in the steam, and improving the dryness of the steam. When the water content in the steam is too high, to achieve the same process effect, more steam may need to be consumed, thus increasing energy consumption. At the same time, the dry steam can improve the heat transfer efficiency, enabling the equipment to perform better and improving production efficiency. The separated condensed water can be discharged in time through the drainage device, preventing the condensed water from accumulating in the system and avoiding problems such as pipeline corrosion and blockage caused by the accumulation of condensed water, reducing the system maintenance cost and maintenance workload.

[0067] In this embodiment, the drain module 6 is used to discharge the condensed water separated by the steam-water separator 5. During the pipeline transportation and equipment use of the steam generated by the boiler, it will condense into water due to temperature reduction. If the condensed water remains in equipment such as heat exchangers, it will occupy the heat transfer area, affecting the heat transfer between the steam and the heated medium and reducing the equipment efficiency. The drain module 6 can timely discharge this condensed water to prevent it from accumulating in the pipelines and equipment. The steam trap automatically opens to discharge the condensed water, and the expression is as follows:

[0068]

[0069]

[0070] In the above formula, is the drainage volume of the steam trap, is the flow coefficient of the steam trap, is the pressure difference between the inlet and outlet of the steam trap, is the density of the condensed water, and are empirical coefficients, is the temperature difference between the steam and the condensed water. In this embodiment, is 0.9, is 0.01.

[0071] In this embodiment, the first valve 11 is disposed in the pipeline between the saturated steam outlet 8 and the steam-water separator 5 for controlling the on-off of the saturated steam and the saturated steam outlet 8; the second valve 12 is disposed in the pipeline between the steam-water separator 5 and the second boiler 2 for controlling the on-off of the saturated steam and the second boiler 2; the third valve 13 is disposed in the pipeline between the second boiler 2 and the superheated steam outlet 10 for controlling the on-off of the superheated steam and the fourth valve 14. When the first valve 11 is opened and the second valve 12, the third valve 13 and the fourth valve 14 are closed, the saturated steam separated by the steam-water separator 5 is sent out through the saturated steam outlet 8; when the first valve 11 is closed and the second valve 12, the third valve 13 and the fourth valve 14 are opened, the saturated steam separated by the steam-water separator 5 enters the second boiler 2 through the second valve 12 to be heated into superheated steam, and then the superheated steam is sent out through the third valve 13 and the fourth valve 14 to the superheated steam outlet 10.

[0072] In this embodiment, the second boiler 2 is provided with a steam superheater. The function of the steam superheater is to further heat the saturated steam to make it into superheated steam, remove the moisture in the steam, improve the dryness and purity of the steam, thereby improving the quality of the steam. The temperature and enthalpy value of the superheated steam are higher than those of the saturated steam, and it has higher energy. When the first valve 11 is closed and the second valve 12, the third valve 13 and the fourth valve 14 are opened, the saturated steam separated by the steam-water separator 5 enters the second boiler 2 through the second valve 12 to be heated into superheated steam, and then the superheated steam is sent out through the third valve 13 and the fourth valve 14 to the superheated steam outlet 10.

[0073] In this embodiment, the water supply module 7 is used to supply water to the first boiler 1 and the second boiler 2. The first boiler 1 generates steam, resulting in a continuous decrease in the water volume in the first boiler 1. During the operation of the second boiler 2, steam is continuously output for heating the saturated steam, resulting in a continuous decrease in the water volume in the second boiler 2. The water supply module 7 can timely and stably supply the required water to the first boiler 1 and the second boiler 2 to maintain the boiler water level within the normal range and ensure the continuous operation of the first boiler 1 and the second boiler 2.

[0074] In this embodiment, the overpressure discharge module 9 is used to discharge the superheated steam to reduce the pressure in the second boiler 2. During the operation of the second boiler 2, due to fuel supply, load changes and other situations, the internal pressure may rise sharply. When the pressure exceeds the limit that the second boiler 2 can withstand, it will cause serious damage to the furnace body, pipelines, pipe fittings and other related equipment of the second boiler 2. The overpressure discharge module 9 can be automatically opened when the pressure reaches the set safety value, discharge part of the steam in the second boiler 2, quickly reduce the pressure in the furnace, prevent the equipment from being damaged due to overpressure, and protect the integrity and safety of the equipment.

[0075] In this embodiment, the fourth valve 14 is disposed in the pipeline between the third valve 13 and the superheated steam outlet 10, and is used to control the discharge of superheated steam. The fourth valve 14 can accurately control the discharge flow rate of superheated steam. When the load of the downstream equipment at the superheated steam outlet 10 increases and more superheated steam is required, the fourth valve 14 is opened wider to allow more steam to flow into the downstream equipment; conversely, when the load decreases, the fourth valve 14 is closed smaller to reduce the output of superheated steam. By changing the steam discharge volume, the steam pressure at the discharge port is adjusted. When the superheated steam pressure rises, the fourth valve 14 is opened appropriately wider to increase the superheated steam discharge volume and reduce the pressure; when the pressure decreases, the fourth valve 14 is closed smaller to reduce the superheated steam discharge and increase the pressure.

[0076] Embodiment 2

[0077] As Figure 3 shown, a flue structure of a saturated dual-purpose steam boiler includes:

[0078] The first combustion chamber 15, which is used for burning fuel to generate flue gas, is disposed at the bottom of the first boiler 1;

[0079] The first heating surface 16, which is used for heating water to evaporate and form saturated steam, is disposed around the furnace of the first combustion chamber 15 and above;

[0080] The first smoke guide plate 17, which is used for guiding the flue gas of the first combustion chamber 15, is disposed above the first heating surface 16;

[0081] The throttle hole 19, which is used to prevent the back pressure fluctuation caused by the mixing of the flue gas of the second boiler 2 into the first boiler 1 and ensure the normal combustion of the first boiler 1, is disposed at the end of the first smoke guide plate 17;

[0082] The second smoke guide plate 18, which is used for guiding the mixed flue gas of the first combustion chamber 15 and the second combustion chamber 22, is disposed below the second heating surface 20;

[0083] The second heating surface 20, which is used for heating water to evaporate and form saturated steam, is disposed below the smoke outlet 4;

[0084] The connecting flue butterfly valve 21, which is used to control the flue gas flow rate of the second boiler 2 entering the first boiler 1, is disposed in the connecting flue 3;

[0085] The second combustion chamber 22, which is used for burning fuel to generate flue gas, is disposed at the bottom of the second boiler 2;

[0086] The third heating surface 23, which is used for heating saturated steam to form superheated steam, is disposed around the furnace of the second combustion chamber 22 and above;

[0087] The energy-saving section 24 is used to enhance the efficiency of heat exchange and is disposed above the third heating surface 23 .

[0088] In this embodiment, the height of the first smoke guide plate 17 is greater than or equal to the height of the connecting flue 3, so as to prevent the flue gas of the first boiler 1 and the flue gas of the second boiler 2 from directly colliding with each other to cause local vortex and unstable back pressure.

[0089] In this embodiment, the width of the smoke passage formed by the first smoke guide plate 17 gradually decreases along the smoke passage of the first boiler 1 toward the second heating surface 20 , which helps to guide the smoke into the second heating surface 20 .

[0090] In this embodiment, the first heating surface 16, the second heating surface 20 and the third heating surface 23 are of a multi-section bending design or a spiral design, so as to improve the heat exchange efficiency.

[0091] In this embodiment, the area of ​​the first heating surface 16 is greater than the area of ​​the third heating surface 23 , and the area of ​​the third heating surface 23 is greater than or equal to the area of ​​the second heating surface 20 .

[0092] In this embodiment, the length of the flue of the connecting flue 3 is not greater than the height of the second boiler 2 , and the inner diameter of the flue of the connecting flue 3 is less than half of that of the second boiler 2 .

[0093] The flue gas generated by the combustion of fuel in the first combustion chamber 15 passes upward from the first combustion chamber 15 through the first heating surface 16, the throttle hole 19 and the second heating surface 20, and finally is discharged into the smoke outlet 4. The flue gas generated by the combustion of fuel in the second combustion chamber 22 passes upward from the second combustion chamber 22 through the third heating surface 23 and the energy-saving section 24, and then enters the connecting flue 3, and is merged into the flue gas mixing section of the first boiler 1 through the connecting flue butterfly valve 21. After the flue gas generated by the first boiler 1 is mixed, it is discharged into the smoke outlet 4 through the second heating surface 20. The first smoke guide plate 17 and the second smoke guide plate 18 divide the smoke mixing section into two inner and outer chambers and a smoke mixing chamber. The inner chamber contains the smoke of the first boiler 1, and the outer chamber contains the smoke of the second boiler 2 entering from the connecting flue 3. The smoke of the first boiler 1 and the second boiler 2 are mixed upward and discharged through the smoke outlet 4. Through the design of the inner and outer chambers, it is prevented that the flue gas of the first boiler 1 and the flue gas of the second boiler 2 directly collide with each other to cause local vortex, resulting in unstable back pressure, and further causing unstable combustion of the burner of the first boiler 1 or the second boiler 2. Under the action of the smoke guide plate, the flue gas of the first boiler 1 and the flue gas of the second boiler 2 are evenly mixed in the flue gas mixing chamber before entering the second heating surface 20. It is prevented that the flue gas in the inner and outer chambers is stratified and rushes into the third heating surface 23, causing uneven flue gas and unstable back pressure on the third heating surface 23, thereby improving the stability of the burners of the first boiler 1 and the second boiler 2. The throttle ring is provided at the throttle hole 19 to prevent the back pressure fluctuation caused by the mixing of the flue gas of the second boiler 2 into the first boiler 1 from affecting the normal combustion of the burner of the first boiler 1.

[0094] Implementation scheme: When saturated steam is required, the water supply module 7 is started, the first valve 11 is opened, the second valve 12, the third valve 13 and the fourth valve 14 are closed, and the burner of the first boiler 1 is started. The fuel is burned in the first combustion chamber 15 to generate flue gas. The flue gas passes through the first heating surface 16, the throttle hole 19 and the second heating surface 20, and heat is exchanged between the first heating surface 16 and the first heating surface 16 to heat and evaporate water to form saturated steam. The flue gas is discharged through the smoke outlet 4, and the saturated steam is sent to the steam-water separator 5. The steam-water separator 5 separates water droplets in the steam to obtain purer and drier saturated steam. At the same time, the condensed water separated by the steam-water separator 5 is discharged through the drain module 6 to prevent the condensed water from accumulating in the pipeline and equipment. The steam-water separator 5 transports the purified saturated steam to the saturated steam outlet 8 through a pipeline. When superheated steam is required, the water supply module 7 is started, the first valve 11 is closed, the second valve 12, the third valve 13 and the fourth valve 14 are opened, the burner of the first boiler 1 and the burner of the second boiler 2 are started, and the fuel is burned in the first combustion chamber 15 to generate flue gas. The flue gas passes through the first heating surface 16, the throttle hole 19 and the second heating surface 20, and heat is exchanged between the first heating surface 16 and the first heating surface 16 to heat and evaporate water to form saturated steam. The flue gas is discharged through the smoke outlet 4, and the saturated steam is sent to the steam-water separator 5, which separates the water droplets in the steam to obtain purer and drier saturated steam. At the same time, the condensed water separated by the steam-water separator 5 passes through the hydrophobic module 6 is discharged to prevent condensed water from accumulating in pipelines and equipment. The steam-water separator 5 transports the purified saturated steam to the second boiler 2 through a pipeline. The fuel is burned in the second combustion chamber 22 to generate flue gas, which passes upward from the second combustion chamber 22 through the third heating surface 23 and the energy-saving section 24. Heat exchange is performed on the third heating surface 23 to heat the saturated steam to form superheated steam. The superheated steam passes through the third valve 13 and the fourth valve 14 and is discharged through the superheated steam outlet 10, or the superheated steam is discharged through the overpressure discharge module 9 to reduce the internal pressure, etc. The flue gas of the second boiler 2 enters the connecting flue 3, is merged into the flue gas mixing section of the first boiler 1 through the connecting flue butterfly valve 21, and is discharged through the smoke outlet 4.

[0095] The present invention can produce saturated steam and superheated steam under different working conditions. When producing superheated steam, an external independent steam superheater is adopted, and the second boiler 2 shares the smoke outlet 4 of the first boiler 1 through the design of connecting the flue 3, thereby reducing the boiler system cost and the flue gas treatment and maintenance cost. At the same time, it can effectively utilize the flue gas waste heat of the second boiler 2, thereby improving the applicability and energy utilization rate.

[0096] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn of the basic inventive concept. Obviously, those skilled in the art can make various changes and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of equivalent technology of the present invention, the present invention also intends to include these modifications and variations.

Claims

1. A saturated dual-purpose steam boiler, characterized in that, Comprising: A first boiler for burning fuel to generate flue gas and converting liquid water into steam through heat exchange; A second boiler for burning fuel to heat saturated steam into superheated steam; A smoke outlet for discharging the flue gas generated by the boiler, connected to the first boiler; A connecting flue for introducing the flue gas of the second boiler into the first boiler, connecting the first boiler and the second boiler; A steam-water separator for separating water droplets in the steam to obtain purer and drier saturated steam, connected to the first boiler and the second boiler; A drain module for discharging the condensate separated by the steam-water separator and preventing steam leakage, connected to the steam-water separator; A saturated steam outlet for discharging saturated steam, connected to the steam-water separator and the second boiler; A feed module for supplying feed water to the first boiler and the second boiler, connected to the first boiler and the second boiler; An overpressure discharge module for discharging superheated steam to reduce the pressure in the second boiler, connected to the second boiler; A superheated steam outlet for discharging superheated steam, connected to the second boiler; The saturated dual-purpose steam boiler further comprises: A first combustion chamber for burning fuel to generate flue gas, arranged at the bottom of the first boiler; A first heating surface for heating water to evaporate and form saturated steam, arranged in the furnace and above the first combustion chamber; A first smoke guide plate for guiding the flue gas of the first combustion chamber, arranged above the first heating surface; A throttle hole for preventing the backpressure fluctuation caused by the mixing of the flue gas of the second boiler into the first boiler and ensuring the normal combustion of the first boiler, arranged at the end of the first smoke guide plate; A second smoke guide plate for guiding the mixed flue gas of the first combustion chamber and the second combustion chamber, arranged below the second heating surface; A second heating surface for heating water to evaporate and form saturated steam, arranged below the smoke outlet; A connecting flue butterfly valve for controlling the flue gas flow of the second boiler entering the first boiler, arranged in the connecting flue; A second combustion chamber for burning fuel to generate flue gas, arranged at the bottom of the second boiler; A third heating surface for heating saturated steam to form superheated steam, arranged in the furnace and above the second combustion chamber; An energy-saving section for enhancing the heat exchange efficiency, arranged above the third heating surface; The height of the first smoke guide plate is greater than or equal to the height of the connecting flue; The width of the smoke passage formed by the first smoke guide plate gradually decreases along the flue gas passage of the first boiler towards the second heating surface.

2. The saturated dual-purpose steam boiler according to claim 1, characterized in that, It further comprises: A first valve for controlling the on-off of the saturated steam and the saturated steam outlet, arranged in the pipeline between the saturated steam outlet and the steam-water separator; A second valve for controlling the on-off of the saturated steam and the second boiler, arranged in the pipeline between the steam-water separator and the second boiler; A third valve for controlling the on-off of the superheated steam and the regulating valve, arranged in the pipeline between the second boiler and the superheated steam outlet; A fourth valve for controlling the discharge of superheated steam, arranged in the pipeline between the third valve and the superheated steam outlet.

3. A saturated dual-purpose steam boiler according to claim 1, characterized in that, The drain module is provided with a drain valve, and the drain valve automatically opens to discharge condensate water, and the expression is as follows: f(ΔT) = a + bΔT In the above formula, Q is the drainage capacity of the steam trap, and K v is the flow coefficient of the steam trap, ΔP is the pressure difference between the inlet and outlet of the steam trap, and ρ c is the density of the condensed water, a and b are empirical coefficients, and ΔT is the temperature difference between the steam and the condensed water; a is 0.9 and b is 0.

01.

4. A saturated dual-purpose steam boiler according to claim 1, characterized in that, The first heating surface, the second heating surface and the third heating surface are designed in a multi-segment bent shape or a spiral shape.

5. A saturated dual-purpose steam boiler according to claim 4, characterized in that, The area of the first heating surface is larger than the area of the third heating surface, and the area of the third heating surface is larger than or equal to the area of the second heating surface.

6. The saturated dual-purpose steam boiler according to claim 1, characterized in that, The flue length of the connecting flue is not greater than the height of the second boiler, and the inner diameter of the connecting flue is less than half of the second boiler.

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