A single boiler segmented fire tube indirect heating boiler
By designing segmented fire tube bundles and insulation materials in the boiler, the problems of complex structure and low thermal efficiency of the existing boiler are solved, and efficient and safe steam production and easy-to-maintain single-boil segmented fire tube indirect heating boiler is achieved.
Patent Information
- Application Number
- CN202010459256.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-05-27
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2040-05-27
AI Technical Summary
The existing fire-tube and water-tube boilers have complex structures, difficulty in repairing, low thermal efficiency and safety limitations in improving thermal efficiency. In particular, fire-tube boilers are prone to leakage due to stress concentration and corrosion, and water-tube boilers have high parameters and large The water quality requirements are high and the thermal efficiency is not high.
Design a single-pot body section fire tube indirect heating boiler. By setting a fire tube bundle as the heating surface on the outer wall or inner cylinder of the economizer, the fire tube bundle is divided into evaporation section, superheating section and preheating section, and heat insulation is used Materials and adjustment devices to regulate the flue gas flow rate and steam temperature. The fire tube bundle does not need to cross the pot shell. It has a simple structure and is easy to maintain. It also increases the heat transfer area and reduces the smoke exhaust temperature by evenly laying the fire tube bundle.
It realizes a high-thermal efficiency boiler with a simple structure and easy maintenance, reduces the smoke exhaust temperature, avoids the use of overheating pipes, improves the overheating efficiency of steam, and solves the flue gas deflection problem, enhancing the safety and thermal efficiency of the boiler.
Smart Images
Figure CN111520699B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of fire tube boilers, in particular to a single boiler segmented fire tube indirect heating boiler. Background Art
[0002] Boilers are equipment for producing steam or hot water. So far, there are two common types: fire tube boilers and water tube boilers. In fire tube boilers, smoke tubes are set inside the water-filled boiler shell. The smoke generated by fuel combustion flows through the inside of the fire tubes, and the heat is transferred to the fire tubes and then to the water outside the fire tubes, that is, the fire tubes directly transfer heat to the boiler water; in water tube boilers, water tubes are drawn out from the drum, and the smoke flows through the outside of the water tubes, and the heat is transferred to the water tubes and then to the water inside the water tubes.
[0003] A typical fire tube boiler generally includes a boiler shell, a furnace, a throat, a front smoke box, a rear smoke box and a fire tube. The fire tube crosses the water space inside the boiler shell. The two sides of the fire tube are connected to the front smoke box and the rear smoke box respectively. The front smoke box is connected to the chimney. The flue gas generated by the combustion in the furnace enters the rear smoke box through the throat and flows through the fire tube immersed in water, thereby heating the water. The main heating surfaces of the boiler are the furnace and the fire tube.
[0004] A typical water-tube boiler has water pipes (water-cooled walls and convection tube bundles) between the two drums and between the drum and the header. The water pipes are arranged in the furnace. The flue gas generated by the combustion of fuel in the furnace transfers heat to the water pipes through radiation and convection, and then to the water in the water pipes. The main heating surface of the boiler is the water pipes.
[0005] In the typical boiler heat transfer process mentioned above, heat is transferred from the flue gas to the outer surface of the metal by convection or radiation, and then from the outer surface of the metal to the inner surface by conduction, and then to the boiler water by convection from the inner surface. Among them, the heat transfer coefficient from the flue gas to the metal surface is the lowest, which is the weak link of heat transfer. In order to meet the needs of boiler heat load, either the number and length of fire tubes or water tubes are increased to expand the flue gas heat transfer area, or the temperature difference between the flue gas and the metal surface is increased. Fire tubes and water tubes are both pressure-bearing components. Expanding the flue gas heat transfer area will increase the complexity of the equipment and the metal consumption; increasing the temperature difference will lead to an increase in the exhaust gas temperature and reduce the thermal efficiency. Therefore, for small boilers that pursue a simple structure, it is difficult to improve the design thermal efficiency.
[0006] For fire tube boilers, the joints between the fire tubes and the shell are where stress is concentrated and are prone to tearing. There are a large number of fire tubes, which are prone to perforation due to corrosion, overheating, etc., leading to boiler water leakage. This is also one of the main failures of fire tube boilers, and it is difficult to repair after such failures occur.
[0007] For fire tube boilers, the steam generated is saturated steam. If superheated steam is required, a superheater must be added on the high-temperature flue gas side. The superheater is generally a tubular heat exchanger, which makes the equipment structure complex, the superheater tube is prone to leakage, and maintenance is difficult.
[0008] In order to increase the evaporation capacity or thermal power of the fire tube boiler, more heating surfaces, that is, more fire tubes, need to be arranged, which requires a larger shell diameter and water capacity, which will reduce the safety of the boiler and limit the development of large capacity and high parameters of the boiler, resulting in fire tube boilers can only adapt to low parameters and small capacity. However, fire tube boilers have low requirements for water quality.
[0009] For water tube boilers, the joints between the water tubes and the drum are where stress is concentrated and are prone to cracking. There are a large number of water tubes, which are prone to perforation due to corrosion, overheating, etc., leading to boiler water leakage. This is also one of the main failures of water tube boilers and is difficult to repair. For boilers that produce superheated steam, the superheater tubes are also prone to leakage and are difficult to repair.
[0010] For water tube boilers, the heating surface layout is flexible and the thermal efficiency is high, which is suitable for high-parameter and large-capacity boilers. However, the water quality requirements are also high. During operation, the dust accumulation outside the tube is difficult to clean, which will reduce the thermal efficiency.
[0011] For water tube boilers, in order to ensure water circulation in the water tubes, the heat load of the water-cooled wall cannot be too large, and a large area of heating surface is required to reduce the exhaust gas temperature. Since most of the heating area is a pressure pipe, the manufacturing cost is high.
[0012] In order to improve thermal efficiency while maintaining a simple structure, Chinese Patent 201822207011.3 discloses a vertical steam boiler, in which a flue gas channel is formed between the water storage chamber and the furnace wall, and a plurality of baffles are arranged in the flue gas channel to increase the disturbance and circulation time of the flue gas, thereby improving the thermal efficiency of the boiler; Chinese Patent 201721762386.5 discloses a smokeless vertical boiler, in which a flue gas channel is formed between the water tank and the drum, a C-shaped baffle is arranged horizontally on the drum, and a vertical flue gas baffle is arranged on the water tank to extend the contact time between the flue gas and the water tank, increase the contact area, and achieve the purpose of improving efficiency. These are all tubeless boilers, and their common feature is that the heat transfer area is increased by various fins, and the addition of fins with a larger area either leads to a complex structure and difficulty in cleaning smoke dust, or a large volume or even flue gas deviation. If superheated steam is to be produced, superheating pipes need to be arranged, and the structure is more complicated. Summary of the invention
[0013] The present invention provides a single-boiler segmented fire tube indirect heating boiler, which has the advantages of simple structure, convenient manufacturing, maintenance and overhaul, and can ensure sufficient heat exchange area, reduce exhaust gas temperature, improve thermal efficiency, and realize integrated superheated steam production without superheating tubes.
[0014] A single-boiler segmented fire tube indirect heating boiler comprises a boiler shell, one end of which is provided with an economizer, and one side of the economizer is connected with a water inlet pipe;
[0015] The economizer and the boiler shell are connected via a connecting pipe;
[0016] The outer wall and / or inner cylinder of the boiler shell and economizer are provided with fire tube bundles as heating surfaces.
[0017] Preferably, a combustion chamber is provided at the other end of the boiler shell, and the combustion chamber is communicated with the fire tube bundle.
[0018] Preferably, the fire tube bundle is divided into three sections, namely, the evaporation section fire tube bundle, the superheating section fire tube bundle and the preheating section fire tube bundle, the evaporation section fire tube bundle and the superheating section fire tube bundle are arranged on the outer wall and / or inner cylinder of the boiler shell, and the preheating section fire tube bundle is arranged on the outer wall and / or inner cylinder of the economizer; the evaporation section fire tube bundle and the superheating section fire tube bundle, and the superheating section fire tube bundle and the preheating section fire tube bundle are connected respectively with the evaporation section outlet smoke chamber and the superheating section outlet smoke chamber. More preferably, part of the evaporation section fire tube bundle is separated from the other evaporation section fire tube bundles by heat insulation material, or is made of heat insulation material and is arranged as an insulated fire tube bundle, and an overheated steam regulating device is arranged at the bottom of the insulated fire tube bundle, and the overheated steam regulating device is used to regulate the amount of flue gas entering the insulated fire tube bundle.
[0019] Preferably, the top of the fire tube bundle is connected to a smoke exhaust chamber, and the smoke exhaust chamber is provided with a smoke exhaust port.
[0020] Preferably, a steam outlet is connected to the top of the pot shell.
[0021] Preferably, a cleaning hole is provided at the top of the smoke exhaust chamber, and an elastic baffle is provided at the cleaning hole for covering the cleaning hole.
[0022] Preferably, the fire tube bundle is arranged along the direction of the boiler shell and is evenly distributed in a ring shape on the outer wall and / or inner cylinder of the boiler shell and the economizer.
[0023] Preferably, the fire tubes of the fire tube bundle are cylindrical and / or square column-shaped and / or triangular column-shaped.
[0024] The above-mentioned single-boiler segmented fire tube indirect heating boiler has a fire tube bundle arranged along the outer wall of the boiler shell and economizer and / or in the inner tube of the boiler shell and economizer. The fire tube bundle and the boiler shell and economizer are in close contact or fixedly connected together, or are manufactured as a whole to reduce the thermal resistance between the fire tube bundle and the boiler shell and economizer. The flue gas generated by the combustion of the fuel flows through the fire tubes, and the heat is transferred to the fire tube bundle, and the fire tube bundle is then transferred to the boiler shell and economizer, and the boiler shell and economizer are transferred to the water therein.
[0025] The beneficial effects of the present invention are:
[0026] (1) The fire tube bundle tightly connected to the boiler shell and the inside and / or outside of the economizer is used as the main heating surface of the boiler. The fire tube bundle does not need to cross the internal space of the boiler shell. The structure is simple and regular. The fire tube bundle is not a pressure-bearing component and is easy to maintain and repair. There is no cross welding joint between the fire tube and the pressure-bearing boiler shell, and the pressure resistance performance is good;
[0027] (2) The surface area of the fire tube is the heat exchange area between the flue gas and the metal surface of the boiler, and is also the weak link of the boiler heat transfer. The surface area of the fire tube of the present invention can be adjusted arbitrarily without significantly increasing the complexity of the structure. For the same heat transfer amount, by increasing the surface area of the fire tube bundle, the boiler design exhaust temperature can be reduced, thereby improving the thermal efficiency;
[0028] (3) Furthermore, the present invention designs a uniform arrangement of the fire tubes, which can solve the problem of flue gas deviation and also reduce the exhaust temperature to improve efficiency;
[0029] (4) The fire tube of the present invention is preferably designed to be cylindrical and / or square and / or triangular. The regular shape is conducive to cleaning the ash.
[0030] (5) Furthermore, the present invention is provided with an insulated fire tube bundle, through which the flue gas flow rate of the evaporation section fire tube bundle can be adjusted, thereby reasonably adjusting the temperature of the superheated steam. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 It is a boiler with an annular shell.
[0032] Figure 2 It is a boiler with a cylindrical shell.
[0033] In the figure, economizer 1, water inlet pipe 2, connecting pipe 3, boiler shell 4, internal heat transfer fins 5, boiler water 6, combustion chamber 7, superheated steam regulating device 8, fire tube bundle 9, insulated fire tube bundle 901, evaporation section fire tube bundle 902, superheating section fire tube bundle 903, preheating section fire tube bundle 904, evaporation section outlet smoke chamber 10, steam outlet 11, superheating section outlet smoke chamber 12, smoke exhaust port 13, smoke exhaust chamber 14, and cleaning hole 15. DETAILED DESCRIPTION
[0034] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.
[0035] Example 1
[0036] Combination Figure 1, shown in the figure is a single-boiler segmented fire tube indirect heating boiler. The main body of the boiler mainly includes a boiler shell 4 and an economizer 1. The boiler shell 4 and the economizer 1 are both annular and have a hollow inner tube. The economizer 1 is arranged at the upper end of the boiler shell 4, and a water inlet pipe 2 is connected to one side of the economizer 1; the economizer 1 and the boiler shell 4 are connected through a connecting pipe 3. Generally speaking, in order to improve thermal efficiency, the upper end of the connecting pipe 3 is connected to the top side of the economizer 1, and the lower end is connected to the bottom side of the boiler shell 4; the outer wall and the inner tube of the boiler shell 4 and the economizer 1 are both arranged with fire tube bundles 9 as heating surfaces. The fire tube bundles 8 arranged on the outer wall and the fire tube bundles 9 arranged in the inner tube are in close contact with the boiler shell 4 and the economizer 1 through welding or pressing, or other material casting and bonding, or integral manufacturing to reduce thermal resistance. All fire tube bundles 9 do not cross the boiler shell. The fire tube bundles 9 are non-pressure-bearing components, with neat specifications and simple structure, which are convenient for manufacturing and maintenance.
[0037] Preferably, in order to improve thermal efficiency, internal heat transfer fins 5 may be welded inside the economizer 1 and the boiler shell 4 to enhance heat transfer.
[0038] Of course, the fire tube bundle 9 needs smoke to pass through so as to provide heat for the boiler shell 4 . In the present invention, preferably a combustion chamber 7 is provided under the boiler shell 4 , and the combustion chamber 7 is communicated with the fire tube bundle 9 .
[0039] Preferably, the fire tube bundle 9 is divided into three sections, including an evaporation section fire tube bundle 902, an overheating section fire tube bundle 903 and a preheating section fire tube bundle 904 arranged from bottom to top, and the boiler shell 4 is divided into an evaporation section boiler shell and an overheating section boiler shell, and the evaporation section boiler shell and the overheating section boiler shell are connected, and the boiler water is heated and evaporated into steam through the evaporation section boiler shell, and the steam enters the overheating section boiler shell and continues to be heated to become superheated steam. Correspondingly, the evaporation section fire tube bundle 902 and the overheating section fire tube bundle 903 are arranged on the outer side of the boiler shell 4. The wall and inner cylinder correspond to the outer wall and inner cylinder of the evaporation section shell and the superheating section shell, respectively. The preheating section fire tube bundle 904 is arranged on the outer wall and inner cylinder of the economizer 1. When the boiler water initially enters, the heat of the economizer 1 and the preheating section fire tube bundle 904 is used to heat the boiler water. The evaporation section fire tube bundle 902 and the superheating section fire tube bundle 903, and the superheating section fire tube bundle 903 and the preheating section fire tube bundle 904 are connected to the evaporation section outlet smoke chamber 10 and the superheating section outlet smoke chamber 12, respectively. The purpose of setting the evaporation section outlet smoke chamber 10 and the superheating section outlet smoke chamber 12 is to mix the flue gas, make the flue gas temperature more uniform, and reduce heat deviation.
[0040] Preferably, the top of the fire tube bundle 9 is connected to a smoke exhaust chamber 14 , and the smoke exhaust chamber 14 is provided with a smoke exhaust port 13 . The smoke exhaust port 13 is preferably arranged on one side or the top of the smoke exhaust chamber 14 .
[0041] Water enters the economizer 1 from the water inlet pipe 2, and after being heated in the economizer 1, enters the boiler shell 4 through the connecting pipe 3, is heated and evaporated in the boiler shell 4, and the steam is heated in the superheated section of the boiler shell to become superheated steam and is sent out from the steam outlet 11.
[0042] After the flue gas from the combustion chamber 7 heats the bottom of the boiler shell 4, it enters the fire tube bundle 9, and the heat is transferred to the evaporation section fire tube bundle 902. The evaporation section fire tube bundle 902 is tightly connected to the boiler shell 4, and the heat is effectively transferred to the inner surface of the boiler shell 4, and then transferred to the boiler water 6 by convection. The flue gas continues to enter the superheating section fire tube bundle 903 to heat the steam, and then enters the preheating section fire tube bundle 904 to preheat the boiler water 6 in the economizer 1, and finally discharged from the smoke exhaust port 13.
[0043] Boilers improve efficiency by:
[0044] Increasing the heat transfer area on the flue gas side improves efficiency. According to the heat transfer formula
[0045] Q=K·△t·A
[0046] Q——Heat transfer
[0047] K——Heat transfer coefficient
[0048] △t——heat transfer temperature difference
[0049] A——Heat transfer area
[0050] Under a given heat transfer amount Q, as long as there is enough heat transfer area A, the heat transfer temperature difference △t can be maintained at a low value, that is, the exhaust gas temperature can be designed at a low value, thereby improving efficiency. In this boiler, the fire tube bundle serves as the heat transfer surface on the flue gas side. Changing the number, diameter and height of the fire tube bundle 9 can change the heating area on the flue gas side, but it will not significantly increase the complexity of equipment manufacturing and maintenance. The fire tube is not under pressure and will not significantly increase the cost.
[0051] Preferably, part of the evaporation section fire tube bundle 902 is separated from other evaporation section fire tube bundles 902 by heat insulation materials, or is made of heat insulation materials, and is set as an insulated fire tube bundle 901. The bottom of the insulated fire tube bundle 901 is provided with a superheated steam regulating device 8, and the superheated steam regulating device 8 is used to regulate the amount of flue gas entering the insulated fire tube bundle 901. Generally speaking, the insulated fire tube bundle 901 is selected to be arranged on the outer side of the evaporation section fire tube bundle 902, so as to facilitate the adjustment of the superheated steam regulating device 8. The superheated steam regulating device can be arranged in a variety of ways, such as an openable and closable structure, adjusting the size of the opening and closing, or a structure that can be translated. After being translated outward, the amount of flue gas entering the evaporation section fire tube bundle 902 becomes more. An insulated fire tube bundle 901 is provided, and the insulated tube bundle 901 is made of an insulating material or separated from other fire tube bundles 9 by an insulating material, so that the heat of the flue gas is not transferred to the evaporation section fire tube bundle 902, but directly enters the evaporation section outlet smoke chamber 10 from the combustion chamber 7, and the amount of flue gas entering the insulated tube bundle 901 can be adjusted by adjusting the superheated steam regulating device 8. For boilers with high superheat requirements, the boiler shell 4 can be divided into upper and lower parts, namely, the evaporation section boiler shell at the bottom and the superheating section boiler shell at the top. The evaporation section boiler shell and the superheating section boiler shell are connected with flanges to reduce the heat transfer between the evaporation section boiler shell and the superheating section boiler shell, and maintain a higher temperature of the superheating section boiler shell.
[0052] Preferably, a steam outlet 11 is connected to the top of the boiler shell, and superheated steam is discharged from the top of the boiler shell.
[0053] Preferably, there is a cleaning hole 15 at the top of the smoke exhaust chamber 14, and an elastic baffle is provided at the cleaning hole 15 to cover the cleaning hole 15. During operation, the elastic baffle blocks the cleaning hole 15 to prevent smoke from leaking out. When the fire tube bundle 9 needs to be cleaned, a straight stick can be used to penetrate through the cleaning hole 15 to clean the ash in the hole. The design of the elastic baffle is an existing structure.
[0054] Preferably, the fire tube bundle 9 is arranged vertically and evenly arranged in a ring shape on the outer wall and inner cylinder of the boiler shell 4 and the economizer 1. The even arrangement of the fire tube bundle 9 solves the problem of flue gas deviation and can also reduce the exhaust gas temperature and improve efficiency.
[0055] Preferably, in this embodiment, the fire tubes of the fire tube bundle 9 are set to be cylindrical, the fire tube bundle 9 has a regular structure, the resistance of each smoke tube is consistent, and the smoke deviation is reduced. At the same time, by combining the evaporation section outlet smoke chamber 10 and the superheating section outlet smoke chamber 12 to evenly mix the smoke, the thermal deviation can be further eliminated, and the problem of the average exhaust temperature being increased due to the thermal deviation caused by uneven resistance can be solved. Depending on the situation, the fire tubes of the fire tube bundle 9 can also be set to be triangular prisms or square prisms, or a combination of these shapes.
[0056] Preferably, the economizer 1 adopts a uniform annular structure, and the waste heat is recovered by the economizer 1 with a uniform structure, so that the exhaust gas temperature can be reduced and the efficiency can be improved. Furthermore, the annular structure of the economizer 1 is consistent with the structure of the boiler shell 4, that is, the outer diameter and the inner diameter are the same, which can better uniformly arrange the fire tube bundle 9, with a simple structure and high efficiency.
[0057] For the specific size design in actual use, a specific value can be cited, such as: a fire tube bundle 9 composed of Φ40mm circular pipes evenly distributed vertically on the inner tube and outer wall of the annular boiler shell.
[0058] Example 2
[0059] Combination Figure 2 As shown, Example 2 is substantially the same as Example 1, but uses a cylindrical boiler shell 4 and a cylindrical economizer 1, so that the fire tube bundle 9 can only be arranged on the outer wall of the economizer 1 and the boiler shell 4. The boiler shell 4 is also divided into an evaporation section boiler shell and a superheating section boiler shell, and the fire tube bundle 9 is also divided into three sections, including an evaporation section fire tube bundle 902, a superheating section fire tube bundle 903, and a preheating section fire tube bundle 904 arranged from bottom to top.
[0060] For the specific size design in actual use, a specific value can be listed, such as: a fire tube bundle composed of Φ40mm circular pipes is evenly distributed on the outer wall of the circular boiler shell, and the fire tube bundle 9 is welded to the boiler shell 4.
Claims
1. A single-boiler segmented fire tube indirect heating boiler, comprising a boiler shell, characterized in that: An economizer is provided at one end of the boiler shell, and a water inlet pipe is connected to one side of the economizer; The economizer and the boiler shell are connected via a connecting pipe; The economizer and the boiler shell are both annular and have a hollow inner cylinder; The outer wall and / or inner cylinder of the boiler shell and economizer are provided with fire tube bundles as heating surfaces, and a water cavity is formed between the outer wall and the inner cylinder; The top of the fire tube bundle is connected to a smoke exhaust chamber, and the smoke exhaust chamber is provided with a smoke exhaust port; The top of the pot shell is connected with a steam outlet.
2. The single boiler segmented fire tube indirect heating boiler according to claim 1 is characterized in that: A combustion chamber is provided at one end of the boiler shell, and the combustion chamber is communicated with the fire tube bundle.
3. The single boiler segmented fire tube indirect heating boiler according to claim 1, characterized in that: The fire tube bundle is divided into three sections, including an evaporation section fire tube bundle, a superheating section fire tube bundle and a preheating section fire tube bundle. The evaporation section fire tube bundle and the superheating section fire tube bundle are arranged on the outer wall and / or inner cylinder of the boiler shell, and the preheating section fire tube bundle is arranged on the outer wall and / or inner cylinder of the economizer; the evaporation section fire tube bundle and the superheating section fire tube bundle, as well as the superheating section fire tube bundle and the preheating section fire tube bundle are respectively connected with the evaporation section outlet smoke chamber and the superheating section outlet smoke chamber.
4. The single-boiler segmented fire tube indirect heating boiler according to claim 3 is characterized in that: Some of the evaporation section fire tube bundles are separated from other evaporation section fire tube bundles by insulation materials, or are made of insulation materials to form an insulated fire tube bundle. A superheated steam regulating device is provided at the bottom of the insulated fire tube bundle, and the superheated steam regulating device is used to regulate the amount of flue gas entering the insulated fire tube bundle.
5. The single boiler segmented fire tube indirect heating boiler according to claim 1, characterized in that: A cleaning hole is provided at the top of the smoke exhaust chamber, and an elastic baffle is arranged at the cleaning hole to cover the cleaning hole.
6. The single boiler segmented fire tube indirect heating boiler according to claim 1, characterized in that: The fire tube bundle is arranged in the same direction as the boiler shell and / or at a certain angle, and is evenly arranged in a ring shape on the outer wall and / or inner cylinder of the boiler shell and the economizer.
7. The single boiler segmented fire tube indirect heating boiler according to claim 1, characterized in that: The fire tubes of the fire tube bundle are cylindrical and / or square column and / or triangular column shaped.