Condensation steam boiler

Abstract

The invention discloses a condensation steam boiler which comprises a hearth and a plurality of heat exchange pipes arranged in the hearth, the heat exchange pipes are annularly distributed to form a heat exchange pipe ring, and the condensation steam boiler is characterized in that a heat insulation part is arranged on the inner side of the heat exchange pipe ring and divides the heat exchange pipe ring into a main heat exchange area and an overheating area; a water inlet is formed in one end of each heat exchange pipe, a steam outlet is formed in the other end of each heat exchange pipe, the water inlets are formed in one side of the main heat exchange area, and the steam outlets are formed in one side of the overheating area; a medium in the heat exchange pipe is divided into a liquid phase area, a vapor-liquid two-phase mixing area and a vapor state area from the water inlet to the vapor outlet, the liquid phase area is arranged at the main heat exchange area, the vapor state area is arranged at the overheat area, and the vapor-liquid two-phase mixing area is arranged at the joint of the main heat exchange area and the overheat area. The heat exchange effect is improved, the service life is prolonged, and the maintenance rate is reduced.

Description

Technical Field

[0001] The present invention relates to a boiler, and more particularly to a condensing steam boiler. Background Art

[0002] A steam generator, also called a steam heat source machine (commonly known as a boiler), is a mechanical device that uses the heat energy of fuel or other energy sources to heat water into hot water or steam. As a traditional steam generator, it generally adopts a horizontal or vertical structure. The conventional working principle is (taking the case where water flows from the bottom to the top inside the heat exchange tube for heating): By heating the heat exchange tube, the liquid in the heat exchange tube is heated into a gaseous state, and a steam drum is arranged above the heat exchange tube to send out the gaseous water vapor through the steam drum. For steam generators with a water volume greater than or equal to 30L, they belong to special equipment and require supervision and inspection, as well as filing. For steam generators with a water volume less than 30L, they do not fall within the category of special equipment and do not require supervision and inspection, filing, or annual inspection.

[0003] For gas steam generators that are exempt from supervision and inspection and filing, or for conventional steam generators, in order to miniaturize them as much as possible, in the existing structure, taking a vertical device as an example, generally a ring of heat exchange tubes is adopted. Inside this ring of heat exchange tubes is a combustion area, and high-temperature flue gas and thermal radiation are used to heat this ring of heat exchange tubes, heating the liquid inside the heat exchange tubes into a gaseous state (the liquid medium is fed from the bottom of the heat exchange tube, and the gaseous medium is sent out from the top of the heat exchange tube). In this structure, the following problems exist: Since the water in the heat exchange tube is gradually heated from a liquid state to a gaseous water vapor from the bottom to the top, that is, from the bottom to the top inside the heat exchange tube are successively in a liquid state, a liquid-vapor mixed state, and a gaseous state. The heat transfer performance of the gaseous state is poor, but the temperature at each position in the combustion area is basically the same. The high temperature received by the heat exchange tubes in the liquid area and the liquid-vapor mixed state area can be directly transferred to the liquid water to heat it. For example, the temperature received by the heat exchange tubes in the lower liquid and liquid-vapor mixed states is 800°C - 1000°C, which can transfer heat to the liquid water and heat it into a gaseous state, and the situation of dry burning of the heat exchange tubes will not occur, so that the heat exchange tubes at this place will not be burned out. However, due to the poor heat transfer performance of the gaseous state, the heat exchange tubes in the gaseous state area are basically equivalent to being dry burned, and the temperature may approach 500°C or exceed 500°C. For this conventional type of steam generator, in order to solve this problem, the heat exchange tubes in the upper layer (in the gaseous state area) will use heat-resistant alloy steel. This heat-resistant alloy steel is a special alloy steel that can withstand high temperatures of more than 500°C. However, in this structure, since this area is often dry burned, even the heat-resistant alloy steel is easily damaged, resulting in a relatively short service life and a relatively high maintenance rate. Moreover, the cost of the heat-resistant alloy steel is also relatively high.

[0004] If the temperature is lowered, although it can extend the service life and reduce the maintenance rate, there is also the problem of insufficient steam dryness. If the water vapor does not contain liquid water, the steam dryness is 100%. The steam dryness of a boiler meeting the standard should reach over 97%, and that of an excellent boiler should reach over 99%. If the steam dryness is insufficient, it will not only cause more heat loss but also consume more energy (for example, in a gas steam generator, more gas will be consumed). At the same time, if there is too much water in the steam, it cannot meet the production process requirements of some end-users. Summary of the Invention

[0005] The object of the present invention is to provide a condensing steam boiler. By using this structure, it can effectively extend the service life of the equipment, reduce the maintenance rate and cost, and also effectively ensure the use effect of the equipment.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a condensing steam boiler, including a furnace and a plurality of heat exchange tubes arranged in the furnace. The plurality of heat exchange tubes are annularly arranged to form a heat exchange tube circle. An insulating member is provided inside the heat exchange tube circle. The insulating member divides the heat exchange tube circle into a main heat exchange area and a superheat area. The main heat exchange area is a combustion area, and the superheat area is a secondary heat exchange area for high-temperature flue gas; One end of the heat exchange tube is a water inlet, and the other end is a steam outlet. The water inlet is arranged on one side of the main heat exchange area, and the steam outlet is arranged on one side of the superheat area. The liquid medium enters the heat exchange tube through the water inlet, is heated to a gaseous state through the main heat exchange area and the superheat area, and is sent out from the steam outlet; The medium in the heat exchange tube is respectively a liquid phase area, a vapor-liquid two-phase mixing area, and a gaseous area between the water inlet and the steam outlet. The liquid phase area is arranged at the main heat exchange area, the gaseous area is arranged at the superheat area, and the vapor-liquid two-phase mixing area is arranged at the connection between the main heat exchange area and the superheat area.

[0007] In the above technical solution, the outer surface of the insulating member abuts against the inner surface of the heat exchange tube circle.

[0008] In the above technical solution, a plurality of fins are spaced on the outer surface of each heat exchange tube, and the plurality of fins are arranged along the extending direction of the heat exchange tube.

[0009] In the above technical solution, bends are respectively provided on opposite sides of the fin, and the bends abut against the bends of the adjacent upper or lower fins, and the outside of the heat exchange tube between the adjacent two fins forms a flue gas channel; And / or, the side portions of the fins on each heat exchange tube are in contact with the side portions of the fins on the adjacent heat exchange tubes, or the side portions of the fins on each heat exchange tube are arranged close to the side portions of the fins on the adjacent heat exchange tubes.

[0010] In the above technical solution, one end of the bent fin at the main heat exchange area is arranged outside the heat exchange tube coil.

[0011] In the above technical solution, one end of the bent fin at the superheat area is arranged outside the heat exchange tube coil; And / or, the other end of the bent fin at the superheat area is arranged inside the heat exchange tube coil.

[0012] In the above technical solution, a plurality of outer guide plates are further arranged outside the heat exchange tube coil. The side portions of each outer guide plate are respectively connected or in contact with the side portions of the adjacent outer guide plates. Each outer guide plate is arranged opposite to a heat exchange tube, and the outer guide plate is connected to the fin or the heat exchange tube; And / or, a plurality of inner guide plates are arranged in the superheat area. The side portions of each inner guide plate are respectively connected or in contact with the side portions of the adjacent inner guide plates. Each inner guide plate is arranged opposite to a heat exchange tube, and the inner guide plate is connected to the fin or the heat exchange tube.

[0013] In the above technical solution, a plurality of outer guide plates are further arranged outside the heat exchange tube coil. The side portions of each outer guide plate are respectively connected or in contact with the side portions of the adjacent outer guide plates. Each outer guide plate is arranged opposite to a heat exchange tube, and the outer guide plate is connected to the heat exchange tube; And / or, a plurality of inner guide plates are arranged in the superheat area. The side portions of each inner guide plate are respectively connected or in contact with the side portions of the adjacent inner guide plates. Each inner guide plate is arranged opposite to a heat exchange tube, and the inner guide plate is connected to the heat exchange tube.

[0014] In the above technical solution, through holes are respectively arranged on the outer guide plate and the inner guide plate.

[0015] In the above technical solution, the size of the through hole in the vapor region is larger than the size of the through hole in the liquid phase region, and the size of the through hole in the liquid phase region is larger than the size of the through hole in the vapor-liquid two-phase mixing region.

[0016] In the above technical solution, a disturbing inner tube is further arranged in each heat exchange tube. The disturbing inner tube is arranged in the vapor region, and there is a gap between the disturbing inner tube and the inner wall of the heat exchange tube; And / or, the disturbing inner tube is coaxially arranged with the heat exchange tube.

[0017] In the above technical solution, the heat exchange tubes are arranged vertically, the bottom of the heat exchange tubes is the water inlet, and the top of the heat exchange tubes is the steam outlet; And / or, a water inlet header and a steam header are respectively arranged at the bottom and the top of the furnace, the water inlet at the bottom of the heat exchange tube is communicated with the water inlet header, and the steam outlet at the top of the heat exchange tube is communicated with the steam header.

[0018] In the above technical solution, an exhaust port is arranged at the top of the steam header, a steam-water separation plate is arranged in the steam header, and the steam-water separation plate is arranged between the exhaust port and the steam outlet; And / or, the steam-water separation plate is a multi-stage steam-water separation plate.

[0019] In the above technical solution, a condensing heat exchanger is further arranged beside the furnace, and a plurality of rows of condensing side heat exchange tubes arranged at intervals are arranged in the condensing heat exchanger; A first smoke exhaust port is arranged on the superheating zone, and the first smoke exhaust port is communicated with the smoke inlet of the condensing heat exchanger; A smoke exhaust pipe is arranged on the condensing heat exchanger, and the smoke inlet and the smoke exhaust pipe are respectively arranged on both sides of the condensing side heat exchange tubes.

[0020] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: 1. In the present invention, a heat insulation component is directly arranged inside the heat exchange tube coil, and the heat exchange tube coil is divided into a combustion area and a high-temperature flue gas secondary heat exchange area. The liquid medium in the heat exchange tube is in the combustion area, and the gaseous medium in the heat exchange tube is in the high-temperature flue gas secondary heat exchange area. In this way, the combustion area exchanges heat with the liquid medium with strong heat transfer performance, and can concentrate the higher-temperature high-temperature flue gas in the combustion area to exchange heat with the liquid medium, while the lower-temperature high-temperature flue gas performs secondary heating on the gaseous medium, effectively improving the steam dryness. At the same time, it can also prevent the heat exchange tubes in the gaseous area from being damaged by high temperature for a long time. Moreover, the vapor-liquid two-phase mixing area is at the heat insulation component, which can prevent dry burning in the vapor-liquid two-phase mixing area, effectively reducing the maintenance rate, extending the service life, and without using high-temperature resistant steel, which can reduce costs; 2. The present invention can improve the utilization rate of thermal energy, reduce energy consumption and use costs; 3. Fins are also arranged in the present invention to improve the heat exchange effect. At the same time, the fins are also bent to form a flue gas channel, so that the high-temperature flue gas can contact the back of the combustion area as much as possible, making the heat exchange of each position of the heat exchange tube uniform, reducing the heat exchange intensity difference, reducing the wall temperature difference of the heat exchange tube, making the circumferential heat exchange of the heat exchange tube uniform, and extending the service life of the heat exchange tube; 4. Inner and outer guide plates are also arranged in the present invention, which can control the flow path of the high-temperature flue gas, ensure the heat exchange effect and also control the heat exchange effect; 5. In the present invention, a disturbance embedded tube is also arranged inside the heat exchange tube, which can improve the steam dryness and the slightly superheated state. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention; Figure 2 is a three-dimensional structural diagram of Embodiment 1 of the present invention (the arrow is the flow path and direction of the flue gas from the superheated area towards the condensation heat exchanger); Figure 3 is Figure 1 the sectional structural diagram of A-A in Figure 4 is Figure 1 the sectional structural diagram of B-B in Figure 5 is a partial enlarged view of the flow path of the flue gas flowing around the heat exchange tube at the main heat exchange area in Embodiment 1 of the present invention (the arrow is the flow path and direction of the flue gas); Figure 6 is a sectional structural diagram of the heat insulation component and a single heat exchange tube in Embodiment 1 of the present invention (there is a medium inside the heat exchange tube); Figure 7 is a partial enlarged view of the connection between the heat exchange tube and the steam header in Embodiment 1 of the present invention.

[0022] Wherein: 1, furnace; 2, heat exchange tube; 3, heat exchange tube coil; 4, heat insulation component; 5, main heat exchange area; 6, superheated area; 7, first smoke exhaust port; 8, water inlet; 9, steam outlet; 10, liquid phase area; 11, vapor-liquid two-phase mixing area; 12, vapor state area; 13, fin; 14, bend; 15, flue gas channel; 16, outer deflector; 17, through hole; 18, inner deflector; 19, disturbance embedded tube; 20, water inlet header; 21, steam header; 22, exhaust port; 23, steam-water separation plate; 24, primary steam-water separation plate; 25, secondary steam-water separation plate; 26, condensation heat exchanger; 27, smoke exhaust pipe; 28, backfire area of the main heat exchange area; 29, burner. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be further described below in conjunction with the drawings and embodiments: Embodiment 1: Refer to Figures 1-7As shown in the figure, a condensing steam boiler includes a furnace 1 and multiple heat exchange tubes 2 arranged in the furnace 1. The multiple heat exchange tubes 2 are arranged in a ring to form a heat exchange tube ring 3, and there is a spacing between adjacent heat exchange tubes 2. An insulating component 4 is provided inside the heat exchange tube ring 3. The insulating component 4 divides the heat exchange tube ring 3 into a main heat exchange area 5 and a superheat area 6. The main heat exchange area 5 is a combustion area, and the superheat area 6 is a secondary heat exchange area for high-temperature flue gas. A first smoke exhaust port 7 is provided at the superheat area 6 far from the insulating component 4.

[0024] One end of the heat exchange tube 2 is a water inlet 8, and the other end is a steam outlet 9. The water inlet 8 is arranged on one side of the main heat exchange area 5, and the steam outlet 9 is arranged on one side of the superheat area 6. The liquid medium enters the heat exchange tube 2 through the water inlet 8, is heated to a gaseous state through the main heat exchange area 5 and the superheat area 6, and then is sent out from the steam outlet 9. The medium in the heat exchange tube 2 is respectively a liquid phase area 10, a vapor-liquid two-phase mixing area 11, and a gaseous state area 12 between the water inlet 8 and the steam outlet 9. The liquid phase area 10 is arranged on the side of the main heat exchange area 5, the gaseous state area 12 is arranged on the side of the superheat area 6, and the vapor-liquid two-phase mixing area 11 is arranged at the connection between the main heat exchange area 5 and the superheat area 6. The two ends of the vapor-liquid two-phase mixing area 11 are respectively arranged on the side of the main heat exchange area 5 and the side of the superheat area 6.

[0025] In this embodiment, the heat exchange tube coil forms an annular structure, and the heat insulation component is arranged inside the annular structure. The outer surface of the heat insulation component abuts against the inner surface of the heat exchange tube coil, thereby dividing the annular structure into two chambers: the main heat exchange area and the superheat area. The main heat exchange area is the combustion area, and a burner 29 can be arranged therein, while no burner is arranged in the superheat area. The high-temperature flue gas and heat radiation generated by the burner will directly be transmitted to the heat exchange tube coil on its outer side, that is, transmitted to the heat exchange tubes on the side of the main heat exchange area. Since the inside of the heat exchange tubes in the main heat exchange area is mainly a liquid phase area, that is, the inside of the heat exchange tubes in the main heat exchange area is mainly liquid water. Taking the illustrated direction as an example, the bottom of the heat exchange tube is the water inlet, and the liquid water enters the heat exchange tube from the water inlet and exchanges heat with the heat exchange tube through the heat radiation of the combustion area and the high-temperature flue gas, so that the liquid water is gradually vaporized. The liquid level of the liquid phase area is arranged close to the bottom surface of the heat insulation component. In this embodiment, the heat insulation component is made of refractory bricks or other heat insulation materials and heat insulating materials. When the water boils and vaporizes, a large number of bubbles will be generated, and the bubbles rise through the liquid level, that is, the connection part between the main heat exchange area and the superheat area (the heat insulation component) forms a vapor-liquid two-phase mixing area. The heat exchange tubes in this area contain part of liquid water and part of water vapor. Taking the temperature of the high-temperature flue gas in the combustion area as 800°C - 1000°C as an example, after the high-temperature flue gas in the main heat exchange area exchanges heat with the heat exchange tubes, the high-temperature flue gas in the main heat exchange area will be sent out from the spacing between adjacent heat exchange tubes to the outside of the heat exchange tube coil (the backfire area 28 of the main heat exchange area). The temperature of the high-temperature flue gas sent out to the outside of the heat exchange tube coil is about 300°C - 350°C, and then it contacts and exchanges heat with the outer surface of the heat exchange tubes on the outside of the heat exchange tube coil in the superheat area, and then enters the superheat area through the spacing between adjacent heat exchange tubes in the superheat area and contacts and exchanges heat with the outer surface of the heat exchange tubes on the inner side of the heat exchange tube coil in the superheat area. At this time, the high-temperature flue gas inside the superheat area is about 180 - 200°C, and the steam temperature in the vapor-liquid two-phase mixing area and the vapor state area is about 160°C - 180°C. In this way, the high-temperature flue gas in the superheat area and outside the superheat area can be used to exchange heat with the steam and water mist in the heat exchange tube again, thereby improving the steam dryness. At the same time, the contact temperature between the high-temperature flue gas and the heat exchange tubes in the vapor state area does not exceed 400°C, so that the problem of overheating of the heat exchange tubes will not occur, effectively preventing the damage of the heat exchange tubes, effectively reducing the maintenance rate, and prolonging the service life. At the same time, the heat exchange tubes are made of ordinary boiler steel, and there is no need to use higher-cost high-temperature-resistant materials, which can effectively reduce the cost.

[0026] Moreover, in this embodiment, through the setting of the heat insulation component, the high-temperature area can be basically controlled at the liquid phase area, and heat exchange is carried out with liquid water as much as possible. Since the heat transfer performance of liquid water is good, the heat exchange effect is good, effectively improving the heat exchange effect, saving energy consumption, and reducing the use cost.

[0027] Moreover, when the heat exchange tubes are exposed to high temperatures, inside the heat exchange tubes at the vapor-liquid two-phase mixing zone, liquid water will adhere to the inner walls of the heat exchange tubes (there will be liquid water within a certain distance on the inner walls above the liquid level, and it is in contact with the inner walls of the heat exchange tubes. There is no liquid water near the axis of the heat exchange tubes, or only some liquid water carried out by bubbles. The middle part is mainly water vapor with a not particularly high dryness). The heat transfer performance of liquid water is stronger, and the heat exchange effect is better. Thus, it can effectively prevent the heat exchange tubes on the main heat exchange area side at the heat insulation component from experiencing dry burning problems, prevent damage to the heat exchange tubes at the heat insulation component, and effectively ensure the service life.

[0028] Furthermore, to improve the heat exchange effect, as shown in Figure 5 , on the outer surface of each heat exchange tube 2, a plurality of fins 13 are arranged at intervals, and the plurality of fins 13 are arranged along the extending direction of the heat exchange tube 2. In this way, the heat exchange tubes are finned tubes, which can increase the contact area between the heat exchange tubes and the high-temperature flue gas, thereby improving the heat exchange effect. Of course, due to the relatively high temperature in the main heat exchange area, finned tubes may not be used, and smooth tubes (without fins, the surface of the heat exchange tubes is smooth) can be adopted.

[0029] As shown in Figure 5 , on the opposite sides of each fin 13, there are respectively provided bends 14, and the bends 14 abut against the bends 14 of the adjacent upper or lower fins 13, and the outside of the heat exchange tube 2 between the two adjacent fins 13 forms a flue gas channel 15.

[0030] In this embodiment, the two sides of all the fins are bent downward respectively (of course, they can also be bent upward). If no bends are provided, in this way, the fins play a role in increasing the contact area with the flue gas and improving the heat exchange effect. At the same time, when the high-temperature flue gas in the main heat exchange area passes through the heat exchange tubes and is sent out of the heat exchange tube coil, the flue gas will come into contact with the outer surface of the inner end of the heat exchange tube (the inner side of the heat exchange tube coil, that is, the combustion area side), and its contact area with the outer end of the heat exchange tube (the outer side of the heat exchange tube coil, that is, the backfire area side of the main heat exchange area) will be less. Since the heat exchange tubes on the combustion area side are subject to better heat radiation heat transfer and heat convection heat transfer effects and greater heat transfer intensity, while the heat radiation heat transfer and heat convection heat transfer effects on the backfire area side of the main heat exchange area will be worse, resulting in a greater temperature difference between the inner and outer tube walls of the heat exchange tubes, and further affecting the service life of the heat exchange tubes. Therefore, in this embodiment, through the setting of the bends, it is used to adjust the flow path of the high-temperature flue gas passing through the heat exchange tubes, to increase the contact area and / or time between the high-temperature flue gas and the backfire area side of the main heat exchange area of the heat exchange tubes, and to make the heat exchange of the heat exchange tubes more uniform in the circumferential direction as much as possible, reduce the temperature difference between the inner and outer tube walls of the heat exchange tubes, and extend the service life of the heat exchange tubes.

[0031] Furthermore, to ensure the heat exchange effect and the contact area and heat exchange effect between the high-temperature flue gas and the fins and heat exchange tubes, therefore, the side portions of the fins on each heat exchange tube are in contact with the side portions of the fins on the adjacent heat exchange tubes, or the side portions of the fins on each heat exchange tube are arranged close to the side portions of the fins on the adjacent heat exchange tubes. In this way, the high-temperature flue gas is sent out from the main heat exchange area to the outside of the heat exchange tube bundle and enters the superheat area from the outside of the heat exchange tube bundle. The high-temperature flue gas can only or mostly pass through the flue gas channel and flow along the path of the flue gas channel, and try not to flow out from the spacing between the fins of adjacent heat exchange tubes. Thus, it can fully ensure the contact between the high-temperature flue gas and the fins and heat exchange tubes, effectively improve the heat exchange effect, make full use of heat energy, save energy consumption, and reduce the use cost.

[0032] See Figure 5 As shown, to precisely control the flow direction of the flue gas, therefore, the bent end of the fin 13 at the main heat exchange area 5 is arranged on the outside of the heat exchange tube bundle 3. Two bends are symmetrically arranged on both sides of the fin. The bent end is arranged between adjacent heat exchange tubes, and the other end is outside the heat exchange tube bundle. In this way, since the main heat exchange area is the combustion area, the thermal radiation therein is stronger, the temperature of the high-temperature flue gas is higher, and the heat exchange effect is better. Therefore, one end of the fin at the main heat exchange area is outside the heat exchange tube bundle, that is, the bent part of the fin of the heat exchange tube is at the outer end of the heat exchange tube, and the other end is not arranged in the main heat exchange area, that is, the bend is mainly in the backfire area of the main heat exchange area. An outlet for the flue gas is formed between the two bends. This outlet is preferably smaller than the diameter of the heat exchange tube or smaller than the radius of the heat exchange tube, and the outlet of the flue gas is arranged facing the axis of the heat exchange tube bundle. And no bend is arranged on one side of the fin in the main heat exchange area. In this way, it can ensure that the high-temperature flue gas in the main heat exchange area fully contacts and exchanges heat with the inner side of the heat exchange tube. The flue gas channel at the main heat exchange area is an arc-shaped channel. The flue gas flows outwards from both sides of the heat exchange tube between the upper and lower adjacent fins, and then due to the existence of the bend, the flow path of the flue gas will be changed. It will flow around the heat exchange tube, flow towards the outer ends of the two bends, and flow out from the outlet of the flue gas. It can make the flue gas flow around the outer surface of the heat exchange tube and contact the backfire side of the heat exchange tube, which can strengthen the convective heat exchange between the high-temperature flue gas and the heat exchange tube in the backfire area of the main heat exchange area, thereby reducing the temperature difference between the tube walls of the heat exchange tube, improving the uniformity of heat exchange in the circumferential direction of the heat exchange tube, and prolonging the service life of the heat exchange tube.

[0033] Similarly, one end of the bent fin at the overheating area is arranged inside the heat exchange tube coil. The two bends are symmetrically arranged on both sides of the middle of the fin. One end of the bend is arranged between adjacent heat exchange tubes, and the other end is inside the heat exchange tube coil and is in the overheating area, that is, most of the bent parts are arranged in the overheating area. Since the temperature of the high-temperature flue gas outside the heat exchange tube coil will exceed the temperature of the high-temperature flue gas in the overheating area, the heat exchange effect of the heat exchange tubes at the overheating area can be enhanced, the uniformity of the circumferential heat exchange of the heat exchange tubes at the overheating area can be improved, and the service life of the heat exchange tubes can be prolonged.

[0034] Certainly, as another embodiment, all the bends are only arranged outside the heat exchange tube coil (which can reduce the processing difficulty and production cost), that is, all the bends are in the backfire area of the main heat exchange area. Since the temperature of the high-temperature flue gas at the overheating area and its backfire area of the main heat exchange area is not very high, and the temperature difference is only more than 100 degrees Celsius (the temperature difference between the main heat exchange area and its backfire area may be close to the temperature difference of 500°C - 700°C, and the temperature difference is particularly large), the heat exchange is relatively uniform and will not affect the service life of the heat exchange tubes.

[0035] As another preferred embodiment, one end of the bend of the fin at the overheating area is arranged outside the heat exchange tube coil; the other end of the bend of the fin at the overheating area is arranged inside the heat exchange tube coil. That is: the bends at the overheating area are symmetrically arranged on the opposite sides of the heat exchange tube. One end of the bend is outside the heat exchange tube coil, and the other end is inside the heat exchange tube coil, so that the sizes of the smoke inlet and outlet of the flue gas channel at the overheating area are smaller than the diameter or the radius of the heat exchange tube. In this way, when the flue gas passes through the flue gas channel, the high-temperature flue gas will first contact and exchange heat with the outer end side of the heat exchange tube, then contact the inner end side of the heat exchange tube, and then be sent out from the inner end side of the heat exchange tube, so that the high-temperature flue gas fully contacts the circumference of the heat exchange tube and improves the heat exchange effect.

[0036] See Figure 5 As shown, a plurality of outer guide plates 16 are further arranged outside the heat exchange tube coil 3. The side parts of each outer guide plate 16 are respectively connected or in contact with the side parts of the adjacent outer guide plates 16. Each outer guide plate 16 is arranged opposite to a heat exchange tube 2, and the outer guide plate 16 is connected to the fin 13 or the heat exchange tube 2. Through holes 17 are arranged on the outer guide plate 16.

[0037] In the present invention, the outer deflector has two installation structures. The outer deflector is connected to the heat exchange tubes or the outer deflector is connected to the fins. If the fins are not provided, the outer deflector is directly connected to the heat exchange tubes. Since the outer deflectors are connected to each other, they form an annular structure, which is equivalent to providing an annular cover outside the heat exchange tube circle (the outer deflector can only contact the heat exchange tubes at the edge or part of the edge, or contact the heat exchange tubes through support rods, as long as it does not affect the flue gas being sent out from the main heat exchange area and then sent into the superheat area). Moreover, the outer deflector is arranged close to the heat exchange tube circle. After the high-temperature flue gas in the main heat exchange area comes out of the heat exchange tube circle, it will be restricted by the annular cover, so that the high-temperature flue gas can contact all positions of the heat exchange tubes as much as possible, improving the heat exchange effect. At the same time, in order to enable the heat exchange flue gas to be smoothly sent out of the outer deflector and then enter the superheat area, through holes are provided. In this way, the high-temperature flue gas can be sent out of the outer deflector through the through holes and then sent into the superheat area from the outer deflector. More preferably, the through holes are arranged opposite to the axis of the heat exchange tube circle, and there are multiple through holes, which are arranged at intervals along the length direction of the outer deflector. In this way, the high-temperature flue gas sent out from the main heat exchange area will be blocked by the outer deflector and fully contact and exchange heat with the back-fire area of the main heat exchange area of the heat exchange tubes, and then be sent out through the through holes, not only ensuring the heat exchange effect, but also making the temperature difference of the tube wall of the heat exchange tubes small and having a long service life.

[0038] If the fins are provided, during the assembly of the heat exchange tubes, it is difficult to ensure that the fins on all the heat exchange tubes contact the fins on the adjacent heat exchange tubes, resulting in a gap between the fins on the adjacent heat exchange tubes. As a result, part of the high-temperature flue gas will flow through the gap between the fins on the adjacent heat exchange tubes, which will affect the heat exchange effect. Therefore, the outer deflector is provided. The inner wall of the outer deflector is connected to the fins on each heat exchange tube, which is equivalent to covering an annular outer deflector outside a columnar structure formed by multiple fins. Moreover, the adjacent outer deflectors are in contact or connected to each other. Preferably, the overlapping method or the snap connection method is adopted, so that the annular structure formed by multiple outer deflectors covers the outside of the heat exchange tube circle, and the through holes on each outer deflector are directly opposite to the position between two bends, so that the high-temperature flue gas can be quickly and directly sent out through the through holes after flowing out of the flue gas channel. Or the high-temperature flue gas in the back-fire area of the main heat exchange area flows into the flue gas channel through the through holes and then is sent into the superheat area, improving the heat exchange effect. Among them, the through holes can be strip-shaped through holes.

[0039] See Figure 3As shown, a plurality of inner flow guiding plates 18 are provided in the overheating zone 6. The side portions of each inner flow guiding plate 18 are respectively connected to or in contact with the side portions of adjacent inner flow guiding plates 18. Each inner flow guiding plate 18 is disposed opposite to a heat exchange tube 2. The inner flow guiding plate 18 is connected to the fin 13 or the heat exchange tube 2 (if the heat exchange tube is a smooth tube, the inner flow guiding plate may only be in contact with the heat exchange tube at the edge portion or through a support rod, as long as it does not affect the flue gas entering the overheating zone from the outside). Among them, through holes are provided on the inner flow guiding plate, and the through holes are strip-shaped through holes. The installation structure of the inner flow guiding plate is similar to or the same as that of the outer flow guiding plate, and it can be connected to the fin or directly connected to the heat exchange tube. In this way, according to the heat transfer intensity required in different regions (liquid phase region, vapor-liquid two-phase mixing region, and vapor phase region), the distribution of the flue gas flow field can be optimized. For the liquid phase region, the heat transfer intensity of the flue gas can be enhanced. For the vapor-liquid two-phase mixing region or the transition region (the connection between the vapor-liquid two-phase mixing region and the liquid phase region is the transition region, and the connection between the vapor-liquid two-phase mixing region and the vapor phase region is also the transition region), the heat transfer intensity of the flue gas can be reduced or increased, so as to adjust the convective heat transfer of the flue gas according to the positions of the vapor and liquid in the heat exchange tube, avoid excessive heat transfer intensity in local regions, and improve the service life of the heat exchange tube.

[0040] Among them, the size of the through hole in the vapor phase region is larger than the size of the through hole in the liquid phase region, and the size of the through hole in the liquid phase region is larger than the size of the through hole in the vapor-liquid two-phase mixing region. In this way, since the temperature of the high-temperature flue gas entering the overheating zone is not very high, and the temperature required in the vapor phase region is not particularly high, and the heat transfer property of the vapor phase is poor, the size of the through hole at this place is the largest, and the required heat transfer effect can be the lowest. The flue gas temperature in the liquid phase region itself is high, and the heat transfer property of the liquid phase is the best, and its heat transfer effect can be set higher, so the through hole here can be set slightly smaller. The through hole in the vapor-liquid two-phase mixing region is the smallest. Since there is a liquid state and a vapor state in this region, but it is not a pure liquid state, the heat transfer property is worse than that of the pure liquid state, but better than that of the vapor state. Since part of the vapor-liquid two-phase mixing region is in the main heat exchange region, the temperature of the high-temperature flue gas in the part of the vapor-liquid two-phase mixing region in the main heat exchange region is the same as that in the liquid phase region, and the heat transfer effect of the vapor-liquid two-phase mixing region is worse than that of the liquid phase region. Therefore, in order to protect the heat exchange tube in the vapor-liquid two-phase mixing region and prevent the damage of the heat exchange tube at this place, the through hole in the vapor-liquid two-phase mixing region is set to be the smallest, which can reduce the heat transfer intensity, thereby playing a role in protecting the heat exchange tube (since the temperature of the high-temperature flue gas in the liquid phase region and part of the vapor-liquid two-phase mixing region is the same, and the size of the through hole in the vapor-liquid two-phase mixing region is smaller, the flow rate of the high-temperature flue gas in the vapor-liquid two-phase mixing region will be smaller, so as to reduce the heat transfer intensity of the heat exchange tube in the vapor-liquid two-phase mixing region and protect the heat exchange tube in the vapor-liquid two-phase mixing region). Of course, the sizes of the through holes at each position can also be the same.

[0041] See Figure 3 and 6 As shown, a disturbing embedded tube 19 is further provided in each heat exchange tube 2. The disturbing embedded tube 19 is arranged in the vapor region 12, and there is a spacing between the outer surface of the disturbing embedded tube 19 and the inner surface of the heat exchange tube 2 (multiple rods can be arranged on the outer surface of the disturbing embedded tube to connect with the inner wall of the heat exchange tube, or the top of the disturbing embedded tube is connected to the steam header to fix the disturbing embedded tube, or other fixing methods can be adopted). The disturbing embedded tube 19 is coaxially arranged with the heat exchange tube 2.

[0042] Since the steam in the vapor region mainly undergoes convective heat transfer and the temperature difference between the inside and outside of the heat exchange tube does not need to be considered, a disturbing embedded tube is arranged in the vapor region, which can reduce the volume of the vapor region. At the same time, the internal steam can contact the inner wall of the heat exchange tube as much as possible, improving the convective heat transfer effect, thereby increasing the steam dryness or raising it to a slightly superheated state.

[0043] See Figure 3 and 6 As shown, the heat exchange tube 2 is arranged vertically. The bottom of the heat exchange tube 2 is the water inlet 8, and the top of the heat exchange tube 2 is the steam outlet 9. An inlet header 20 and a steam header 21 are respectively arranged at the bottom and top of the furnace 1. The water inlet 8 at the bottom of the heat exchange tube 2 is communicated with the inlet header 20, and the steam outlet 9 at the top of the heat exchange tube 2 is communicated with the steam header 21.

[0044] In this way, the external water is sent into the inlet header, and all the heat exchange tubes are supplied with water through the inlet header, so as to ensure that the liquid levels of all the heat exchange tubes are the same or basically the same, and the flow rate of the heat exchange tubes can be accurately controlled to accurately ensure the steam dryness. The steam sent out by all the heat exchange tubes is all concentrated and sent into the steam header, and after being collected by the steam header, it is sent out together. It can send out the steam of all the heat exchange tubes through an independent pipeline.

[0045] Wherein, an exhaust port 22 is arranged at the top of the steam header 21, and a steam-water separation plate 23 is arranged in the steam header 21. The steam-water separation plate 23 is arranged between the exhaust port 22 and the steam outlet 9. The steam-water separation plate is a multi-stage steam-water separation plate.

[0046] In this embodiment, the steam-water separation plate is a two-stage steam-water separation plate. The two-stage steam-water separation plate includes a primary steam-water separation plate 24 and a secondary steam-water separation plate 25. The primary steam-water separation plate adopts a mesh plate structure and can separate the liquid water in the steam. The secondary steam-water separation plate adopts a steam-water baffle structure and further separates the water in the steam by using the centrifugal force of the steam flow to improve the steam dryness.

[0047] See Figure 1 、 2 As shown in Figure 1 , 2 and Figure 4, a condensing heat exchanger 26 is further provided beside the furnace 1, and a plurality of rows of condensing side heat exchange tubes arranged at intervals are provided in the condensing heat exchanger 26.

[0048] A first smoke exhaust port 7 is provided on the superheating zone 1. The first smoke exhaust port and the heat insulation component are respectively arranged at both ends of the superheating zone. One end of the first smoke exhaust port 7 is communicated with the smoke inlet of the condensing heat exchanger 26, and the other end of the first smoke exhaust port 7 is communicated with the superheating zone 6. In this embodiment, a hole can be provided in the middle of the steam header, and this hole constitutes the first smoke exhaust port. Its bottom is communicated with the superheating zone, and the top is communicated with the condensing heat exchanger. The medium-temperature flue gas after heat exchange in the superheating zone (the high-temperature flue gas after passing through the superheating zone exchanges heat with the heat exchange tubes in the superheating zone, and the temperature drops to medium-temperature flue gas), after being sent out from the first smoke exhaust port, enters the condensing heat exchanger and exchanges heat with the condensing side heat exchange tubes in the condensing heat exchanger.

[0049] A smoke exhaust pipe 27 is provided on the condensing heat exchanger 26. The smoke inlet of the condensing heat exchanger 26 and the smoke exhaust pipe 27 are respectively arranged on both sides of the condensing side heat exchange tubes (the liquid inlet and the smoke exhaust pipe are respectively arranged on the upper side and the lower side of the condensing side heat exchange tubes, or can also be on the left side, the right side, or the front side, the rear side).

[0050] In this embodiment, the smoke inlet of the condensing heat exchanger is arranged at its top, and the smoke exhaust pipe is arranged at the side part below it. The smoke inlet is connected to the first smoke exhaust port through a pipeline. The condensing side heat exchange tubes are designed with a multi-pass water circulation. The inlet of the condensing side heat exchange tubes is connected to an external water source. The outlet of the condensing side heat exchange tubes can be separately connected to an external pipeline, or can be connected to the inlet of the water inlet header. Preferably, it is connected to the inlet of the water inlet header. After the medium-temperature flue gas passes through the condensing side heat exchange tubes, it is then discharged from the smoke exhaust pipe. In this way, the water in the condensing side heat exchange tubes can be heated or preheated by the medium-temperature flue gas with not particularly high temperature, and then the heated water is sent into the water inlet header and then into the heat exchange tubes subsequently, and thus can be heated and vaporized more quickly, thereby saving energy consumption, reducing costs, and improving the utilization rate of energy.

[0051] Meanwhile, in the present invention, by setting the heat insulation component, the condensing steam boiler can be made as small as possible, making the equipment more miniaturized.

[0052] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In the description of the present invention, the meaning of "a plurality of" is two or more unless otherwise specifically defined.

[0053] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral body; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For example, the two form a mechanical abutment or contact connection method through abutment, contact, etc. The two may also be directly hung or hung through an intermediate medium. It may also be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A condensing steam boiler, comprising a furnace and a plurality of heat exchange tubes arranged in the furnace, wherein the plurality of heat exchange tubes are arranged in a ring to form a heat exchange tube ring, characterized in that: A heat insulation component is provided on the inner side of the heat exchange tube ring, and the heat insulation component divides the heat exchange tube ring into a main heat exchange area and a superheating area. The main heat exchange area is a combustion area, and the superheating area is a secondary heat exchange area for high-temperature flue gas; One end of the heat exchange tube is a water inlet, and the other end is a steam outlet. The water inlet is arranged at one side of the main heat exchange zone, and the steam outlet is arranged at one side of the superheat zone. The liquid medium enters the heat exchange tube through the water inlet, and is heated into a vapor state by the main heat exchange zone and the superheat zone, and then is sent out from the steam outlet. The medium in the heat exchange tube is respectively a liquid phase zone, a vapor-liquid two-phase mixing zone and a vapor state zone from the water inlet to the steam outlet. The liquid phase zone is arranged at the main heat exchange zone, the vapor state zone is arranged at the superheat zone, and the vapor-liquid two-phase mixing zone is arranged at the connection between the main heat exchange zone and the superheat zone.

2. The condensing steam boiler according to claim 1, characterized in that: The outer surface of the heat insulation component abuts against the inner surface of the heat exchange tube ring.

3. The condensing steam boiler according to claim 1, characterized in that: A plurality of fins are arranged at intervals on the outer surface of each heat exchange tube, and the plurality of fins are arranged along the extension direction of the heat exchange tube.

4. The condensing steam boiler according to claim 3, characterized in that: The two opposite sides of the fin are respectively provided with bends, the bends are against the bends of the adjacent upper or lower fins, and the outside of the heat exchange tube between the two adjacent fins forms a flue gas channel; And / or, the side of the fin on each heat exchange tube contacts the side of the fin on an adjacent heat exchange tube, or the side of the fin on each heat exchange tube is arranged close to the side of the fin on an adjacent heat exchange tube.

5. The condensing steam boiler according to claim 4, characterized in that: The bent end of the fin at the main heat exchange area is arranged on the outside of the heat exchange tube coil.

6. The condensing steam boiler according to claim 4, characterized in that: The bent end of the fin at the superheating zone is arranged on the outside of the heat exchange tube coil; And / or, the other bent end of the fin at the superheating zone is arranged on the inner side of the heat exchange tube coil.

7. The condensing steam boiler according to claim 3, characterized in that: A plurality of outer guide plates are also provided on the outside of the heat exchange tube ring, the side of each outer guide plate is connected or in contact with the side of the adjacent outer guide plate, each outer guide plate is arranged opposite to a heat exchange tube, and the outer guide plate is connected to the fin or the heat exchange tube; And / or, a plurality of inner guide plates are provided in the overheating zone, the side of each inner guide plate is respectively connected to or in contact with the side of an adjacent inner guide plate, each inner guide plate is arranged opposite to a heat exchange tube, and the inner guide plate is connected to the fin or the heat exchange tube.

8. The condensing steam boiler according to claim 1, characterized in that: A plurality of outer guide plates are also provided on the outer side of the heat exchange tube ring, and the side of each outer guide plate is connected or in contact with the side of the adjacent outer guide plate, and each outer guide plate is arranged opposite to a heat exchange tube, and the outer guide plate is connected to the heat exchange tube; And / or, a plurality of inner guide plates are provided in the overheating zone, the side of each inner guide plate is respectively connected to or in contact with the side of an adjacent inner guide plate, each inner guide plate is arranged opposite to a heat exchange tube, and the inner guide plate is connected to the heat exchange tube.

9. The condensing steam boiler according to claim 7 or 8, characterized in that: The outer guide plate and the inner guide plate are respectively provided with through holes.

10. The condensing steam boiler according to claim 9, characterized in that: The through hole size in the vapor phase region is larger than the through hole size in the liquid phase region, and the through hole size in the liquid phase region is larger than the through hole size in the vapor-liquid two-phase mixing region.

11. The condensing steam boiler according to claim 1, characterized in that: Each of the heat exchange tubes is further provided with a disturbance embedded tube, the disturbance embedded tube is arranged in the vapor zone, and there is a distance between the disturbance embedded tube and the inner wall of the heat exchange tube; And / or, the disturbance embedded tube is coaxially arranged with the heat exchange tube.

12. The condensing steam boiler according to claim 1, characterized in that: The heat exchange tube is arranged vertically, the bottom of the heat exchange tube is a water inlet, and the top of the heat exchange tube is a steam outlet; And / or, a water inlet header and a steam header are respectively provided at the bottom and the top of the furnace, the water inlet at the bottom of the heat exchange tube is connected to the water inlet header, and the steam outlet at the top of the heat exchange tube is connected to the steam header.

13. The condensing steam boiler according to claim 12, characterized in that: The top of the steam header is provided with a steam exhaust port, and a steam-water separation plate is provided inside the steam header, and the steam-water separation plate is arranged between the steam exhaust port and the steam outlet; And / or, the steam-water separation plate is a multi-stage steam-water separation plate.

14. The condensing steam boiler according to claim 1, characterized in that: A condensing heat exchanger is also provided beside the furnace, and a plurality of rows of condensing side heat exchange tubes arranged at intervals are provided in the condensing heat exchanger; The superheating zone is provided with a first smoke exhaust port, and the first smoke exhaust port is connected to the smoke inlet of the condensing heat exchanger; The condensing heat exchanger is provided with a smoke exhaust pipe, and the smoke inlet and the smoke exhaust pipe are respectively arranged on the upper and lower sides of the condensing side heat exchange pipe.

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