Saturated dual-purpose steam boiler and flue structure thereof

Abstract

The invention relates to the technical field of boilers, in particular to a saturated dual-purpose steam boiler and a flue structure thereof.The saturated dual-purpose steam boiler comprises a first boiler used for combusting fuel to generate smoke and converting liquid water into steam through heat exchange; the second boiler is used for burning fuel to heat the saturated steam into superheated steam; the smoke outlet is used for discharging smoke generated by the boiler; the communicating flue is used for guiding flue gas of the second boiler into the first boiler; the steam-water separator is used for separating water drops in the steam to obtain purer and dry saturated steam; the water draining module is used for draining condensed water separated by the steam-water separator and preventing steam leakage at the same time; the water supply module is used for conveying water to the first boiler and the second boiler; and the overpressure discharge module is used for discharging overheated steam to reduce the pressure in the second boiler. The steam generator has the beneficial effects that saturated steam and superheated steam under different working conditions can be produced, local vortex caused by direct hedging of smoke can be prevented, one smoke outlet is shared, and the applicability is improved.

Description

Technical Field

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

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

[0003] In the prior art, saturated steam or superheated steam is usually produced by different boiler equipment respectively. In the scenario where saturated steam and superheated steam are required at the same time, a single boiler equipment cannot meet the usage requirements. For some boilers that can produce saturated steam and superheated steam at the same time, the flue gas in the boiler may offset and cause local vortexes, resulting in unstable back pressure. Summary of the invention

[0004] In response to the shortcomings 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 the direct impact of flue gas from causing local vortices and resulting in unstable back pressure, and share a smoke outlet, thereby improving applicability.

[0005] The following is the technical solution of the present invention, a saturated dual-purpose steam boiler, comprising: The first boiler is used to burn fuel to produce flue gas and convert liquid water into steam through heat exchange; The second boiler is used to burn fuel to heat saturated steam into superheated steam; A smoke outlet, used to discharge smoke generated by the boiler, connected to the first boiler; A connecting flue, used to introduce the flue gas of the second boiler into the first boiler, connecting the first boiler and the second boiler; The steam-water separator is used to separate water droplets from the steam to obtain purer and drier saturated steam, and is connected to the first boiler and the second boiler; A drain module is used to discharge the condensed water separated by the steam-water separator and prevent steam leakage, and is connected to the steam-water separator; The saturated steam outlet is used to discharge saturated steam and is connected to the steam-water separator and the second boiler; A water supply module, used for delivering water to the first boiler and the second boiler, and connecting the first boiler and the second boiler; An overpressure discharge module, used for discharging superheated steam to reduce the pressure in the second boiler, connected to the second boiler; The superheated steam outlet is used to discharge the superheated steam and is connected to the second boiler.

[0006] As a preferred solution of the present invention, it also includes: The first valve is used to control the on-off of saturated steam and the saturated steam outlet, and is arranged in the pipeline between the saturated steam outlet and the steam-water separator; The second valve is used to control the on / off of the saturated steam and the second boiler and is arranged in the pipeline between the steam-water separator and the second boiler; The third valve is used to control the on-off of the superheated steam and the regulating valve, and is arranged in the pipeline between the second boiler and the superheated steam outlet; The fourth valve is used to control the discharge of superheated steam and is arranged in the pipeline between the third valve and the superheated steam outlet.

[0007] 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 condensed water. The expression is as follows: In the above formula, is the discharge capacity 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 condensed water, and is the empirical coefficient, is the temperature difference between steam and condensate; is 0.9, is 0.01.

[0008] A flue structure of a saturated dual-purpose steam boiler, comprising: A first combustion chamber, used for burning fuel to generate flue gas, is disposed at the bottom of the first boiler; The first heating surface is used to heat and evaporate water to form saturated steam, and is arranged in the furnace around and above the first combustion chamber; A first smoke guide plate, used for guiding the smoke of the first combustion chamber, and arranged above the first heating surface; The throttle hole is used to prevent the back pressure fluctuation of the first boiler caused by the mixing of the flue gas from the second boiler, so as to ensure the normal combustion of the first boiler, and is arranged at the end of the first smoke guide plate; A second smoke guide plate, used for guiding the mixed smoke from the first combustion chamber and the second combustion chamber, and arranged below the second heating surface; The second heating surface is used to heat and evaporate water to form saturated steam and is arranged below the smoke outlet; The connecting flue butterfly valve is used to control the flue gas flow rate of the second boiler into the first boiler and is arranged in the connecting flue; A second combustion chamber, used for burning fuel to generate flue gas, is disposed at the bottom of the second boiler; The third heating surface is used to heat the saturated steam to form superheated steam and is arranged in the furnace around and above the second combustion chamber; The energy-saving section is used to enhance the efficiency of heat exchange and is arranged above the third heating surface.

[0009] As a preferred solution of the present invention, the height of the first smoke guide plate is greater than or equal to the height of the connected flue.

[0010] As a preferred solution of the present invention, the width of the smoke passage formed by the first smoke guide plate gradually decreases along the first boiler smoke passage toward the second heating surface.

[0011] As a preferred solution of the present invention, the first heating surface, the second heating surface and the third heating surface are of multi-section bending design or spiral design.

[0012] As a preferred solution 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.

[0013] As a preferred solution of the present invention, the length of the flue of the connecting flue is not greater than the height of the second boiler, and the inner diameter of the flue of the connecting flue is less than half of the second boiler.

[0014] The beneficial effects of the present invention are as follows: saturated steam and superheated steam under different working conditions can be produced. When producing superheated steam, an external independent steam superheater is adopted. Moreover, through the design of connecting the flue, the second boiler shares the smoke outlet of the first boiler, and can prevent the direct impact of the flue gas to cause local vortex and cause unstable back pressure, thereby reducing the boiler system cost and the flue gas treatment and maintenance cost. At the same time, the waste heat of the flue gas of the second boiler can be effectively utilized, thereby improving the applicability and energy utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of a saturated dual-purpose steam boiler of the present invention; Figure 2 This is the operation control diagram of the saturated dual-purpose steam boiler of the present invention; Figure 3 The figure is a structural diagram of the flue of the saturated dual-purpose steam boiler of the present invention; In the figure: 1. first boiler; 2. second boiler; 3. connected flue; 4. smoke outlet; 5. steam-water separator; 6. drain module; 7. water supply 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. butterfly valve connected to flue; 22. second combustion chamber; 23. third heating surface; 24. energy-saving section. DETAILED DESCRIPTION

[0016] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0017] Embodiment 1: like Figure 1 and Figure 2 As shown, a saturated dual-purpose steam boiler comprises: The first boiler 1 is used to burn fuel to generate flue gas, convert liquid water into steam through heat exchange, and is connected to a steam-water separator 5, a smoke outlet 4 and a connecting flue 3; A smoke outlet 4, used for discharging smoke generated by the boiler, connected to the first boiler 1; A connecting flue 3 is used to introduce the flue gas of the second boiler 2 into the first boiler 1, connecting the first boiler 1 and the second boiler 2; The steam-water separator 5 is used to separate water droplets from the steam to obtain purer and drier saturated steam, and is connected to the first boiler 1, the saturated steam outlet 8 and the second boiler 2; A drain module 6, used to discharge condensed water separated by the steam-water separator 5 and prevent steam leakage, connected to the steam-water separator 5; The first valve 11 is used to control the on-off of the saturated steam and the saturated steam outlet 8, and is arranged in the pipeline between the saturated steam outlet 8 and the steam-water separator 5; A saturated steam outlet 8, used for discharging saturated steam, connected to the steam-water separator 5 and the second boiler 2; The second valve 12 is used to control the on / off of the saturated steam and the second boiler 2, and is arranged in the pipeline between the steam-water separator 5 and the second boiler 2; The second boiler 2 is used for burning fuel to heat saturated steam into superheated steam, and is connected to the flue 3, the water supply module 7, the superheated steam outlet 10 and the overpressure discharge module 9; A water supply module 7, used for supplying water to the first boiler 1 and the second boiler 2, and connecting the first boiler 1 and the second boiler 2; An overpressure discharge module 9, used for discharging superheated steam to reduce the pressure in the second boiler 2, connected to the second boiler 2; The third valve 13 is used to control the on / off of the superheated steam and the fourth valve 14, and is arranged in the pipeline between the second boiler 2 and the superheated steam outlet 10; The fourth valve 14 is used to control the discharge of the superheated steam and is arranged in the pipeline between the third valve 13 and the superheated steam outlet 10; The superheated steam outlet 10 is used to discharge the superheated steam and is connected to the second boiler 2 .

[0018] In this embodiment, the first boiler 1 is provided with a steam generator, which 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, which is transferred to the water in the steam generator through a heat exchanger, radiation, convection, etc. When the water absorbs enough heat and the temperature rises to the boiling point, the water molecules change from liquid to gas 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.

[0019] In this embodiment, the smoke outlet 4 discharges the smoke of the first boiler 1 and the second boiler 2. When the first boiler 1 and the second boiler 2 are in operation, the fuel burns in the furnace to generate a large amount of combustion exhaust gas, which contains carbon dioxide, water vapor, sulfur dioxide, nitrogen oxides and incompletely burned particulate matter. The main function of the smoke outlet 4 is to smoothly discharge the exhaust gas generated by these combustions from the boiler system so that the combustion process in the boiler can be carried out continuously and stably. The smoke outlet 4 adjusts the pressure in the furnace by controlling the exhaust gas discharge to keep it within a suitable range. When the pressure in the furnace is too high, the exhaust gas discharge is increased through the smoke outlet 4 to reduce the furnace pressure; when the pressure is too low, the exhaust gas discharge is appropriately reduced to maintain the pressure stable, avoid flame ejection, air leakage and other problems caused by abnormal furnace pressure, and ensure the safety and stability of boiler operation. At the same time, the second boiler 2 shares the smoke outlet 4 of the first boiler 1, which can facilitate the centralized discharge and treatment of smoke, which can not only simplify the boiler system structure, but also reduce the boiler system cost and smoke treatment maintenance cost.

[0020] 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, thereby reducing the boiler system cost and the flue gas treatment and maintenance cost. 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 flue gas waste heat of the second boiler 2 and improve energy utilization.

[0021] In this embodiment, the steam-water separator 5 separates water droplets from the steam to obtain purer and drier saturated steam. The steam generated from the steam generator of the first boiler 1 often carries some moisture. The steam-water separator 5 can separate the moisture entrained in the steam to make the steam drier and purer, reduce the water content in the steam, and improve the dryness of the steam. When the water content in the steam is too high, in order to achieve the same process effect, more steam may be required, thereby increasing energy consumption. At the same time, dry steam can improve heat transfer efficiency, enable the equipment to perform better, and improve production efficiency. The separated condensed water can be discharged in time through the drainage device to prevent the condensed water from accumulating in the system, avoiding problems such as pipeline corrosion and blockage caused by the accumulation of condensed water, and reducing the system maintenance cost and maintenance workload.

[0022] In this embodiment, the drain module 6 is used to discharge the condensed water separated by the steam-water separator 5. The steam generated by the boiler will condense into water due to the decrease in temperature during pipeline transportation and equipment use. If the condensed water is retained in equipment such as heat exchangers, it will occupy the heat exchange area, affect the heat transfer between the steam and the heated medium, and reduce the efficiency of the equipment. The drain module 6 can discharge the condensed water in time to prevent it from accumulating in the pipeline and equipment. The steam trap automatically opens to discharge the condensed water, and the expression is as follows: In the above formula, is the discharge capacity 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 condensed water, and is the empirical coefficient, is the temperature difference between steam and condensed water. In this embodiment, is 0.9, is 0.01.

[0023] In this embodiment, the first valve 11 is arranged in the pipeline between the saturated steam outlet 8 and the steam-water separator 5, and is used to control the on-off of the saturated steam and the saturated steam outlet 8; the second valve 12 is arranged in the pipeline between the steam-water separator 5 and the second boiler 2, and is used to control the on-off of the saturated steam and the second boiler 2; the third valve 13 is arranged in the pipeline between the second boiler 2 and the superheated steam outlet 10, and is used to control the on-off of the superheated steam and the fourth valve 14. When the first valve 11 is opened, the second valve 12, the third valve 13 and the fourth valve 14 are closed, and 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, 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 to the superheated steam outlet 10 through the third valve 13 and the fourth valve 14.

[0024] In this embodiment, the second boiler 2 is provided with a steam superheater, the function of which is to further heat the saturated steam to make it superheated steam, remove the moisture in the steam, improve the dryness and purity of the steam, and thus improve the quality of the steam. The temperature and enthalpy 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 to the superheated steam outlet 10 through the third valve 13 and the fourth valve 14.

[0025] In this embodiment, the water supply module 7 is used to deliver water to the first boiler 1 and the second boiler 2. The first boiler 1 generates steam, which causes the amount of water in the first boiler 1 to decrease continuously. During the operation of the second boiler 2, steam is continuously output for heating saturated steam, which causes the amount of water in the second boiler 2 to decrease continuously. The water supply module 7 can timely and stably replenish the required water to the first boiler 1 and the second boiler 2 to maintain the boiler water level within a normal range and ensure the continuous operation of the first boiler 1 and the second boiler 2.

[0026] In this embodiment, the overpressure discharge module 9 is used to discharge superheated steam to reduce the pressure in the second boiler 2. During the operation of the second boiler 2, the internal pressure may rise sharply due to fuel supply, load changes, etc. When the pressure exceeds the bearing limit of the second boiler 2, 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 automatically open 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.

[0027] In this embodiment, the fourth valve 14 is arranged 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 of superheated steam. When the load of the downstream equipment at the superheated steam outlet 10 increases and more superheated steam is needed, the fourth valve 14 is opened to allow more steam to flow into the downstream equipment; conversely, when the load decreases, the fourth valve 14 is closed to reduce the output of superheated steam. The steam pressure at the outlet is adjusted by changing the discharge volume of steam. When the superheated steam pressure increases, the fourth valve 14 is appropriately opened to increase the discharge volume of superheated steam and reduce the pressure; when the pressure decreases, the fourth valve 14 is closed to reduce the discharge of superheated steam and increase the pressure.

[0028] Embodiment 2 like Figure 3 As shown, a flue structure of a saturated dual-purpose steam boiler comprises: The first combustion chamber 15 is used to burn fuel to generate flue gas and is disposed at the bottom of the first boiler 1; The first heating surface 16 is used to heat and evaporate water to form saturated steam, and is arranged in the furnace around and above the first combustion chamber 15; A first smoke guide plate 17, used for guiding the smoke of the first combustion chamber 15, and disposed above the first heating surface 16; The throttle hole 19 is used to prevent the back pressure fluctuation of the first boiler 1 caused by the mixing of the flue gas of the second boiler 2, so as to ensure the normal combustion of the first boiler 1, and is arranged at the end of the first smoke guide plate 17; The second smoke guide plate 18 is used to guide the mixed smoke from the first combustion chamber 15 and the second combustion chamber 22, and is arranged below the second heating surface 20; The second heating surface 20 is used to heat and evaporate water to form saturated steam and is arranged below the smoke outlet 4; The flue butterfly valve 21 is used to control the flue gas flow rate of the second boiler 2 entering the first boiler 1 and is arranged in the flue 3; The second combustion chamber 22 is used to burn fuel to generate flue gas and is disposed at the bottom of the second boiler 2; The third heating surface 23 is used to heat the saturated steam to form superheated steam and is arranged in the furnace around and above the second combustion chamber 22; The energy-saving section 24 is used to enhance the efficiency of heat exchange and is disposed above the third heating surface 23 .

[0029] 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.

[0030] 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 .

[0031] 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.

[0032] 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 .

[0033] 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 .

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Obviously, various changes and modifications may be made to the present invention by those skilled in the art without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such changes and modifications if they fall within the scope of the technical equivalents of the present invention.

Claims

1. A saturated dual-purpose steam boiler, characterized in that: include: The first boiler is used to burn fuel to produce flue gas and convert liquid water into steam through heat exchange; The second boiler is used to burn fuel to heat saturated steam into superheated steam; A smoke outlet, used to discharge smoke generated by the boiler, connected to the first boiler; A connecting flue, used to introduce the flue gas of the second boiler into the first boiler, connecting the first boiler and the second boiler; The steam-water separator is used to separate water droplets from the steam to obtain purer and drier saturated steam, and is connected to the first boiler and the second boiler; A drain module is used to discharge the condensed water separated by the steam-water separator and prevent steam leakage, and is connected to the steam-water separator; The saturated steam outlet is used to discharge saturated steam and is connected to the steam-water separator and the second boiler; A water supply module, used for delivering water to the first boiler and the second boiler, and connecting the first boiler and the second boiler; An overpressure discharge module, used for discharging superheated steam to reduce the pressure in the second boiler, connected to the second boiler; The superheated steam outlet is used to discharge the superheated steam and is connected to the second boiler.

2. A saturated dual-purpose steam boiler according to claim 1, characterized in that: Also includes: The first valve is used to control the on-off of saturated steam and the saturated steam outlet, and is arranged in the pipeline between the saturated steam outlet and the steam-water separator; The second valve is used to control the on / off of the saturated steam and the second boiler and is arranged in the pipeline between the steam-water separator and the second boiler; The third valve is used to control the on-off of the superheated steam and the regulating valve, and is arranged in the pipeline between the second boiler and the superheated steam outlet; The fourth valve is used to control the discharge of superheated steam and is 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 equipped with a drain valve, which automatically opens to discharge condensed water. The expression is as follows: In the above formula, is the discharge capacity 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 condensed water, and is the empirical coefficient, is the temperature difference between steam and condensate; is 0.9, is 0.

01.

4. A flue structure of a saturated dual-purpose steam boiler, applicable to a saturated dual-purpose steam boiler according to any one of claims 1 to 3, characterized in that: include: A first combustion chamber, used for burning fuel to generate flue gas, is disposed at the bottom of the first boiler; The first heating surface is used to heat and evaporate water to form saturated steam, and is arranged in the furnace around and above the first combustion chamber; A first smoke guide plate, used for guiding the smoke of the first combustion chamber, and arranged above the first heating surface; The throttle hole is used to prevent the back pressure fluctuation of the first boiler caused by the mixing of the flue gas from the second boiler, so as to ensure the normal combustion of the first boiler, and is arranged at the end of the first smoke guide plate; A second smoke guide plate, used for guiding the mixed smoke from the first combustion chamber and the second combustion chamber, and arranged below the second heating surface; The second heating surface is used to heat and evaporate water to form saturated steam and is arranged below the smoke outlet; The connecting flue butterfly valve is used to control the flue gas flow rate of the second boiler into the first boiler and is arranged in the connecting flue; A second combustion chamber, used for burning fuel to generate flue gas, is disposed at the bottom of the second boiler; The third heating surface is used to heat the saturated steam to form superheated steam and is arranged in the furnace around and above the second combustion chamber; The energy-saving section is used to enhance the efficiency of heat exchange and is arranged above the third heating surface.

5. The flue structure of a saturated dual-purpose steam boiler according to claim 4, characterized in that: The height of the first smoke guide plate is greater than or equal to the height of the connected smoke duct.

6. The flue structure of a saturated dual-purpose steam boiler according to claim 4, characterized in that: The width of the smoke passage formed by the first smoke guide plate gradually decreases along the first boiler smoke passage toward the second heating surface.

7. The flue structure of a saturated dual-purpose steam boiler according to claim 4, characterized in that: The first heating surface, the second heating surface and the third heating surface are of multi-section bending design or spiral design.

8. The flue structure of a saturated dual-purpose steam boiler according to claim 7, characterized in that: 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.

9. The flue structure of a saturated dual-purpose steam boiler according to claim 4, characterized in that: The length of the flue of the connecting flue is not greater than the height of the second boiler, and the inner diameter of the flue of the connecting flue is less than half of that of the second boiler.

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