Gas-steam boiler for strengthening heat transfer by building gaps through curved surfaces of special-shaped pipes

Abstract

The invention discloses a gas-steam boiler for strengthening heat transfer by building gaps through curved surfaces of special-shaped pipes. The gas-steam boiler comprises standard water pipes, curved-surface special-shaped water pipes, smoke pipes, an upper header, a lower header, a smoke shell, a burner, a condenser, a chimney and a controller. A single side or a symmetrical surface of the curved-surface special-shaped water pipe is concave inwards to form an arc shape, the curved-surface special-shaped water pipe and the standard water pipe are vertically staggered and annularly arranged, curved-surface gap flue gas channels which are uniformly distributed along the circumference are formed between the adjacent pipes, laminar flow strengthens heat exchange, a central high-temperature area is eliminated, heat load distribution is uniform, heat exchange is low in resistance and efficient, and only a flow of 50-300mm is needed when the flue gas temperature is reduced to below 300 DEG C; meanwhile, the heat transfer element with the smoke pipe embedded in the water pipe is adopted, smoke coming out of the gap channel goes upwards to wash the water pipe row and then enters the smoke pipe to turn back to wash the inner surface of the smoke pipe and secondarily exchanges heat with the water pipe, the smoke pipe does not bear direct flame and high-temperature smoke radiation, the local heat load and the heat flux density are reduced, and the space utilization rate is increased. Low-carbon, low-resistance and efficient heat exchange of the gas-steam boiler is realized, and the steel consumption of the boiler is reduced.

Description

Technical Field

[0001] The invention relates to the field of gas steam boilers, and in particular to a gas steam boiler with a gap constructed by a special-shaped tube curved surface to enhance heat transfer. Background Art

[0002] Gas steam boilers have the characteristics of high efficiency, energy saving, green environmental protection, stable operation and convenient maintenance. There is a large demand for gas steam boilers in urban areas. Urban areas are small and the installation space is limited. Gas steam boilers are required to have a compact structure, small footprint, high efficiency and energy saving, while also being able to meet a large amount of thermal energy demand. By improving the heat transfer elements of gas steam boilers, the gap heat exchange method is adopted to form laminar flow enhancement and eliminate the central high temperature area; the technology of embedding smoke pipes in water pipes is adopted to significantly reduce the water volume in gas steam boilers. This improves the overall space utilization of the boiler, improves the boiler efficiency, greatly reduces the boiler water volume, and significantly reduces the heat loss caused by the start and stop of the boiler. The existing technology adopts the concept of slot-type heat exchange laminar flow enhancement, such as CN113091031A applied by Xi'an Jiaotong University, a combined slot-type gas steam boiler uses tile fins installed on heat exchange tubes to form axial slot channels evenly distributed along the circumference, introducing laminar flow enhancement design into traditional furnace types, which has the advantages of high thermal efficiency, low flue gas resistance, small size, small water volume, and rapid start and stop of the furnace. However, the tile fins are not resistant to high temperatures and have low rigidity. During use, the boiler output needs to be considered to prevent the fins from deforming due to excessive heat load, so there is room for improvement.

[0003] The existing heat transfer element with smoke pipe embedded in water pipe, such as the CN219473621U vertical gas boiler applied by Chongqing Taihu Boiler Co., Ltd., has serious safety hazards: 1. The inner surface of the water pipe in the furnace is subjected to strong radiation heat exchange, and the end of the smoke pipe welded on the inner side of the water pipe is close to the burner flame. On the one hand, it may allow the natural gas that is not fully burned to directly enter the smoke pipe, causing fuel waste; on the other hand, the smoke pipe is subjected to direct flame and high-temperature smoke radiation, and the local heat load and heat flux density are extremely large. In addition, the smoke pipe end and the water pipe are connected by uneven saddle-shaped intersecting line fillet welding. The smoke pipe is very easy to overheat and cause the pipe end to crack, resulting in serious safety accidents. 2. The end of the embedded smoke pipe is a 90-degree elbow structure. The inner side of the fillet weld at the connection between the elbow and the water pipe is prone to scaling or crevice corrosion, which causes local overheating and even cracking and leakage. Summary of the invention

[0004] In order to solve the problems existing in gas steam boilers, the purpose of the present invention is to provide a gas steam boiler with gap-enhanced heat transfer constructed by a special-shaped tube curved surface, and an innovative single-sided or double-sided concave special-shaped tube is constructed. A gap channel composed of a special-shaped tube and a water pipe is used to eliminate the central high-temperature area in the traditional heat exchange process. When the flue gas passes through the gap channel, the entire channel is in a boundary layer area with strong heat and mass transfer, and the heat transfer coefficient can reach 140W / (m 2 ∙℃); the special-shaped tube has strong rigidity and no fin structure, which can withstand the convection scouring and radiation of high-temperature flue gas above 1300℃ without thermal deformation, enabling gas steam boilers to operate safely under high power and high heat flux density, and only requires a flow of 50mm to 300mm to reduce the flue gas temperature to below 300℃, and the flue gas resistance is less than 1500Pa.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: In the first aspect, the present invention provides a gas steam boiler with gap enhanced heat transfer constructed by the curved surface of a special-shaped tube. The boiler is arranged vertically, including an annular tube row, an upper header, and a lower header. The curved special-shaped tubes are spaced from the standard water tubes or the curved special-shaped tubes are arranged in a circle to form an annular tube row. There are tile-type gap channels between adjacent curved special-shaped tubes or between the curved special-shaped tubes and the standard water tubes; the space surrounded by adjacent annular tube rows is a furnace; the two ends of the curved special-shaped tubes are connected to the upper header and the lower header, and embedded smoke pipes are arranged in the curved special-shaped tubes and the standard water pipes. The inlet and outlet of the embedded smoke pipes face the outside of the boiler, and the steel-aluminum composite inner fin tubes are coupled inside the embedded smoke pipes; a partition is welded outside the annular tube row, and a gap for smoke to pass is formed between the partition and the annular tube row, and the gap gradually decreases from top to bottom; the outlet of the embedded smoke pipe is connected to a condenser, and the outside of the furnace area is wrapped with a smoke shell, and there is an annular space for smoke to flow between the smoke shell and the heat exchange tubes and the lower header.

[0006] As a further optimization, a burner is also included which is installed in the upper header. The burner adopts a diffusion burner or a full premixed burner. Both the upper header and the lower header are annular, and the burner is installed on the inner side of the upper header.

[0007] As a further optimization, the curved special-shaped tube 1 is a single-sided concave tube, a first double-sided concave tube, a second double-sided concave tube or a third double-sided concave tube; the single-sided concave tube is an arc-shaped tube with a set depth pressed out on one side; the first double-sided concave tube is an arc-shaped tube with a depth of no more than 1 / 4 of the diameter on both sides of the circular tube, and the first double-sided concave tube has the same diameter as a standard water pipe; the second double-sided concave tube is an arc-shaped tube with a set depth pressed out on both sides of the circular tube, and the second double-sided concave tube is 1 to 2.5 times larger than the diameter of the standard water pipe; the third double-sided concave tube is an arc-shaped tube with a set depth pressed out on both sides of the square steel tube, the square steel can be square or rectangular, and the length and width of the third double-sided concave tube are 0.5 to 2.5 times the diameter of the standard water pipe; embedded smoke pipes are arranged in the first double-sided concave tube and the third double-sided concave tube.

[0008] The annular tube row is arranged in two, three or four circles; when the annular tube row is arranged in two circles, the inner annular tube row is formed by vertically staggered annular arrangement of curved special-shaped tubes and standard water pipes; the outer annular tube row includes an outer water pipe, which is arranged around the inner tube row, and the two ends of the outer water pipe are respectively connected to an upper water chamber and a lower water chamber, the upper water chamber is concentrically arranged closely with the upper header, and the lower water chamber is concentrically arranged closely with the lower header, and partitions are arranged in the upper water chamber and the lower water chamber to force the boiler feed water to flow back and forth up and down between the upper water chamber and the lower water chamber; annular steel plates are arranged on the inner and outer sides of the outer annular tube row, the upper end of the inner annular steel plate flows out of the flue gas channel, and the lower end of the outer annular steel plate flows out of the flue gas channel, and the radial distance between the annular steel plate and the outer annular tube row is less than 5mm.

[0009] As a further optimization, the condenser is set as an external boiler slot coil condenser or a boiler bottom slot coil condenser; when the external boiler slot coil condenser is set at the upper part, the top of the external boiler slot coil condenser is flush with the lower surface of the upper header, and when the external boiler slot coil condenser is set at the lower part, the lower end of the external boiler slot coil condenser is flush with the upper surface of the lower header; the bottom boiler slot coil condenser is set below the lower header.

[0010] As a further optimization, the boiler external slotted coil condenser is composed of two semi-circular external slotted coil condensers.

[0011] As a further optimization, the condenser is a coil-type condenser, in which the coil is composed of a combination of special-shaped coils and standard coils. The special-shaped coils are composed of single-sided or double-sided concave coils. The special-shaped coils and standard coils are arranged alternately to form a gap channel for the flue gas to pass through. The steel plate fitted with the coil is provided with a concave and convex structure adapted to the coil, forming a gap flue gas channel composed of the coil and the steel plate, and the smoke inlet smoke coil of the condenser is arranged circumferentially.

[0012] As a further optimization, the steel-aluminum composite inner wing tube adopts the process of extruding aluminum and has an interference fit with the embedded smoke tube and the smoke tube. The inner wings of the steel-aluminum composite inner wing tube are axisymmetric wings, radial wings, and center-symmetric wings.

[0013] As a further optimization, the condenser adopts a slot type straight tube condenser, which includes an upper water chamber of the condenser, a lower water chamber of the condenser, a tube row arranged between the upper water chamber of the condenser and the lower water chamber of the condenser, an air duct inlet arranged outside the annular tube row, and a bottom outlet annular plate on the inner side of the lower water chamber of the condenser, wherein the tube row is formed by a vertically staggered annular arrangement of curved special-shaped tubes and standard water pipes; partitions are arranged in the upper water chamber of the condenser and the lower water chamber of the condenser to force the boiler feed water to flow back and forth up and down between the upper water chamber and the lower water chamber.

[0014] As a further optimization, the width of the tile-type slit channel is 0.1~4mm.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: The gas steam boiler of the present invention, which uses a special-shaped tube curved surface to construct a gap to enhance heat transfer, adopts the concept of laminar flow enhanced heat exchange, eliminates the central high-temperature zone of the flue gas heat exchange process through the gap channel, so that the boiler flue gas can be reduced from more than 1300°C to less than 300°C with a process of only 50mm to 300mm long, and the flue gas resistance is controlled below 1500Pa, reducing the boiler steam ton steel consumption and water volume; the core heat exchange element special-shaped tube of the gas steam boiler of the present invention, which uses a special-shaped tube curved surface to construct a gap to enhance heat transfer, has a simple structure, and can flexibly adjust the gap with the water pipe by adjusting the size of the extruded arc or the distance between the adjacent special-shaped tubes and the water pipe. It can be applied to boilers of various capacities between 0.1t and 20t, and is easy to process, produce and assemble on a large scale; the gas steam boiler of the present invention, which uses a special-shaped tube curved surface to construct a gap to enhance heat transfer, uses a special-shaped tube to replace the fin to produce gap enhanced heat exchange, and uses the strong rigidity of the steel pipe to withstand 13 High temperature above 00℃ and strong radiation heat exchange will not cause deformation, which can make the gas steam boiler operate safely under high power and high intensity; the invention innovatively constructs a heat transfer element that is embedded in the water pipe and penetrates the outer smoke pipe of the furnace. The end of the smoke pipe is only connected to the intersection line of the outer side of the water pipe by corner welding, and no longer bears the direct radiation of flame and high-temperature flue gas. The local heat load is greatly reduced, and the local heat flux density is greatly reduced. It only bears the flue gas temperature of less than 400℃ after the laminar flow enhanced convection heat exchange through the radial gap of the water pipe bundle, which completely eliminates and avoids the cracking and leakage failure caused by local overheating at the corner welding connection between the end of the smoke pipe and the outer side of the water pipe, and realizes low-resistance laminar flow enhanced high-efficiency heat exchange; the smoke pipe is embedded in the water pipe, which significantly reduces the water volume in the gas steam boiler, reduces the exhaust temperature of the boiler body, and improves the steam thermal efficiency; the structure of the smoke pipe embedded in the water pipe only needs one circle of pipes to complete the flue gas cooling and heat exchange, reducing the floor space of the gas steam boiler; The gas steam boiler of the present invention uses a special-shaped tube curved surface to construct a gap to enhance heat transfer. The design of a smoke tube nested in a water tube significantly reduces the water volume in the steam generator and improves the thermal efficiency of steam. The high-temperature flue gas contacts the water tube to transfer energy to the water tube, and then the flue gas flows into the smoke tube in the water tube and then flows out from the end of the smoke tube. The sub-tube and the water tube form a high-efficiency parent-child heat exchange structure, which increases the distance of the flue gas, improves the heat exchange capacity inside and outside the tube, improves the steam exhaust efficiency, and reduces the heat loss of the start-up and shutdown of the furnace; at the same time, the coupling fin turbulence in the smoke tube is enhanced, which expands the heat exchange area in the tube and promotes the flue gas disturbance, thereby improving the heat exchange efficiency; The present invention adopts a multi-return countercurrent heat exchange design to achieve full heat utilization, reduce the flue gas temperature to below 50°C, reduce the water volume of the device, and realize multi-return integrated low-carbon, low-resistance and high-efficiency heat exchange to meet actual use needs.

[0016] Furthermore, the present invention is a gas steam boiler that uses special-shaped tube curved surfaces to construct gaps to enhance heat transfer. By constructing a boiler-built-in gap-type special-shaped coil condenser and a gap-type special-shaped straight tube condenser, the gaps are arranged below the lower header by utilizing the enhanced laminar flow effect; or the design of an energy-saving condensing water tank with an outer ring tube row jacket is adopted to absorb the waste heat of the flue gas and preheat the feed water, thereby eliminating the space required for an external condenser, and the space occupied by the boiler system can be reduced by 30% to 50%.

[0017] Furthermore, partitions are arranged in the upper and lower water chambers to force the boiler feed water to flow back and forth up and down between the upper water chamber and the lower water chamber, so as to increase the flow velocity on the water side in the tube and reduce supercooled boiling; annular steel plates are arranged inside and outside the outer circle water pipe row, with a flue gas channel flowing out of the upper end of the inner steel plate and a flue gas channel flowing out of the lower end of the outer steel plate. The radial distance between the inner and outer steel plates and the water pipe is less than 5mm, forming a gap heat exchange area for the flue gas to pass through, so that the flue gas coming out from the upper end outlet of the embedded smoke pipe can exchange heat with the gap between the outer circle water pipe in laminar flow, thereby improving the condensation effect.

[0018] Furthermore, the curved special-shaped tubes include a single-sided concave tube, a first double-sided concave tube, a second double-sided concave tube and a third double-sided concave tube. The curved special-shaped tubes are evenly distributed along the circumferential direction to form a circle of annular tube rows. When the boiler power increases, two, three or four circles of annular tube rows are used to increase the heat exchange area. Furthermore, the boiler external slotted coil condenser is composed of a combination of a special-shaped coil and a standard coil. The special-shaped coil is composed of a single-sided or double-sided concave coil. The special-shaped coil and the standard coil are arranged alternately to form a slot channel for the flue gas to pass through. At the same time, the steel plate that fits the condenser and the coil must also match the concave and convex of the coil to form a slot flue gas channel composed of the coil and the steel plate to prevent smoke corridors.

[0019] Furthermore, the slot-type coil condenser at the bottom of the boiler is composed of a combination of special-shaped coils and coils. The special-shaped coils are composed of single-sided or double-sided concave coils. The special-shaped coils and standard coils are arranged alternately to form a slot channel for the flue gas to pass through; at the same time, the steel plate that fits the condenser and the coil must also match the concave and convex of the coil to form a slot flue gas channel composed of the coil and the steel plate to prevent smoke corridors.

[0020] Furthermore, the flue gas enters the air duct inlet arranged outside the annular tube row from the annular space between the smoke shell and the lower header, and is evenly distributed to each gap channel. After condensation and cooling, the flue gas enters the cavity surrounded by the curved special-shaped tube and the standard water pipe, and then enters the condensate collection tray at the bottom of the smoke shell from the bottom outlet tray with the condensate. Partitions are arranged in the upper and lower water chambers to force the boiler feed water to flow back and forth up and down between the upper water chamber and the lower water chamber, so as to increase the flow velocity on the water side in the tube and reduce supercooled boiling. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention is described in detail below with reference to the accompanying drawings and specific implementation methods.

[0022] Figure 1a It is a vertical full-section schematic diagram of a gas-fired steam boiler that uses a special-shaped tube curved surface to construct a gap to enhance heat transfer. Figure 1b This is a horizontal half-section diagram of a gas steam boiler. Figure 1c It is a schematic diagram of the flue gas flow.

[0023] Figure 2 The utility model is a vertical full-section schematic diagram of a gas steam boiler which uses a special-shaped tube curved surface to construct a gap to enhance heat transfer.

[0024] Figure 3a It is a vertical full-section schematic diagram of a gas-fired steam boiler that uses a special-shaped tube curved surface to construct a gap to enhance heat transfer. Figure 3b It is a horizontal half-section schematic diagram of a gas steam boiler.

[0025] Figure 4 The utility model is a vertical full-section schematic diagram of a gas steam boiler which uses a special-shaped tube curved surface to construct a gap to enhance heat transfer.

[0026] Figure 5a It is a vertical full-section schematic diagram of a gas-fired steam boiler that uses a special-shaped tube curved surface to construct a gap to enhance heat transfer. Figure 5b This is a horizontal half-section diagram of a gas-fired steam boiler. Figure 5c It is a horizontal half-section schematic diagram of the gas steam boiler on the b side.

[0027] Figure 6a This is a schematic diagram of a partial cross-section of a single-sided concave tube. Figure 6b This is a partial cross-sectional diagram of the first double-sided concave tube. Figure 6c This is a partial cross-sectional diagram of the second double-sided concave tube. Figure 6d It is a schematic diagram of the partial cross-section of the third double-sided concave tube.

[0028] Figure 7 It is a half-section schematic diagram of a steel-aluminum composite inner fin tube of a gas steam boiler of the present invention, which uses a special-shaped tube curved surface to construct a gap to enhance heat transfer.

[0029] Figure 8a It is a partial cross-sectional schematic diagram of a boiler external gap-type coil condenser of a gas steam boiler in which a gap is constructed by a special-shaped tube curved surface to enhance heat transfer. Figure 8b It is a schematic diagram of a boiler external slotted coil condenser composed of a semicircular external slotted coil condenser.

[0030] Fig. 9 The utility model is a partial cross-sectional schematic diagram of a boiler bottom slot-type coil condenser of a gas steam boiler of the present invention, which uses a special-shaped tube curved surface to construct slots to enhance heat transfer.

[0031] Fig.10aIt is a partial cross-sectional schematic diagram of a slot-type straight tube condenser of a gas steam boiler in which a slot is constructed by a special-shaped tube curved surface to enhance heat transfer. Fig.10b It is a horizontal full-section schematic diagram of a slot-type straight tube condenser.

[0032] In the accompanying drawings, 1-special-shaped tube, 101-single-sided concave tube, 102-first double-sided concave tube, 103-second double-sided concave tube, 104-third double-sided concave tube, 2-standard water pipe, 3-upper header, 4-lower header, 5-burner, 6-condenser, 61-boiler external slot coil condenser, 611-semi-circle external slot coil condenser, 62-boiler bottom slot coil condenser, 63-slot straight tube condenser, 631-air duct inlet, 632-outlet disc, 7-smoke shell, 71-condensate collection tray, 8-chimney, 9-embedded smoke pipe, 91-steel-aluminum composite inner fin tube, 10-partition, 11-outer circle upper water chamber, 12-outer circle lower water chamber, 13-outer circle water pipe, 14-smoke collection box. DETAILED DESCRIPTION

[0033] The invention is described in detail below with reference to the accompanying drawings and specific implementation methods.

[0034] Embodiment 1, as Figure 1a , Figure 1b and Figure 1cAs shown, the present invention provides a gas steam boiler with gap-enhanced heat transfer constructed by using a special-shaped tube curved surface. The boiler is arranged vertically, including a special-shaped curved tube 1, a standard water pipe 2, an upper header 3, a lower header 4, a burner 5, a condenser 6, a smoke shell 7, a chimney 8, an embedded smoke pipe 9 and a controller; the special-shaped curved tube 1 and the standard water pipe 2 are vertically staggered and arranged in an annular ring to form an annular tube row, and the space surrounded by the annular tube row is the furnace, and the space between adjacent special-shaped curved tubes 1 and standard water pipes 2 is shaped like a furnace. The upper and lower ends of all curved special-shaped tubes 1 and standard water pipes 2 are respectively extended into the upper header 3 and the lower header 4 after being reduced in diameter; the upper header 3 and the lower header 4 are annular headers; the upper header 3 is provided with a steam exhaust port, a safety valve, a water level gauge interface, a pressure gauge or a pressure sensor, and a burner installation panel; the lower header 4 is provided with a water inlet, a sewage outlet, a furnace condenser partition plate, and a water level gauge interface; the top of the smoke shell 7 is connected to the outer edge of the bottom of the upper header 3, Surrounding all heat exchange tubes and lower header 4; burner 5 is fixed on the burner mounting panel of upper header 3; boiler external slotted coil condenser 61 is located below upper header 3, used to condense flue gas entering from the annular space of embedded smoke pipe 9; condensate collection tray 71 is located outside condenser 6; chimney 8 is located at one end of condensate collection tray 71, with a gap between it and the outer edge of upper header 3; curved special-shaped tube 1 and standard water pipe 2 are embedded in the embedded smoke pipe 9 that runs through the outer side of the furnace. The ends of the embedded smoke pipe 9 are connected with the intersection lines of the curved special-shaped pipe 1 and the standard water pipe 2 at the outside by fillet welding. A partition 10 is arranged on the outside of the formed annular pipe row to force the smoke to enter the embedded smoke pipe 9. The lower end of the embedded smoke pipe 9 is the smoke inlet. The embedded smoke pipe 9 is coupled with the steel-aluminum composite inner finned tube 91. The partition 10 is welded to the outside of the annular pipe row. As the smoke volume increases from top to bottom, the distance between the partition 10 and the annular pipe row gradually increases from top to bottom, not exceeding 10 mm, and forms a narrow gap heat exchange with the annular pipe row. refer to Figure 6b and 6d The curved special-shaped tube 1 adopts the first double-sided inner concave tube 102 or the third double-sided inner concave tube 104; The condenser 6 is a boiler external slotted coil condenser 61 or a boiler bottom slotted coil condenser 62; The burner 5 is a diffusion burner or a full premix burner.

[0035] refer to Figure 1c , Figure 1aAfter the natural gas and air are evenly mixed at the front end of the burner 5, they enter the furnace from top to bottom for combustion. The flue gas generated by the combustion enters the axial gap channel where the curved special-shaped tubes 1 and the standard water tubes 2 are staggered under the joint constraints of the burner installation panel and the lower header partition plate. After the flue gas exchanges heat in the gap channel, it is forced to enter the embedded smoke tube 9 from the lower end of the embedded smoke tube 9 under the action of the conical partition 10 to flush its inner surface, and enter the boiler external gap type coil condenser 61 from the upper end outlet of the embedded smoke tube 9 for condensation and cooling. The condensed flue gas passes through the smoke shell 7 and the condensate collection tray 71, discharges the condensed water, and then flows upward into the chimney 8 to leave the boiler; the boiler feed water first enters the condenser 6 to absorb the waste heat of the flue gas, and then enters the lower header 4 to be evenly distributed to each curved special-shaped tube 1 and the standard water tube 2. While flowing upward, it absorbs heat and vaporizes into water vapor, rises to the upper header 3, and leaves the boiler from the exhaust port of the upper header.

[0036] like Figure 2 As shown, the present invention is a gas steam boiler that uses a special-shaped tube curved surface to construct a gap to enhance heat transfer. The boiler's external gap type coil condenser 61 can also be installed at the lower outer side of the boiler. The lower end of the boiler's external gap type coil condenser 61 is flush with the upper surface of the lower header 4. The flue gas from the upper end outlet of the embedded smoke pipe 9 goes downward into the annular space in the smoke shell 7, and goes outward into the condenser 6 for condensation and cooling. The condensed flue gas enters the condensate collection tray 71 at the bottom of the smoke shell 7, and after the condensate is discharged, it flows upward into the chimney 8 to leave the boiler.

[0037] like Figure 3a and Figure 3b As shown, the boiler bottom slot-type coil condenser 62 is installed at the bottom of the boiler, below the lower header 4. The upper end of the boiler external slot-type coil condenser 62 is close to the lower end of the lower header 4. The flue gas coming out from the upper end outlet of the embedded smoke pipe 9 goes downward into the annular space in the smoke shell 7, and then goes downward into the condenser 6 for condensation and cooling. The condensed flue gas enters the condensate collection tray 71 at the bottom of the smoke shell 7, and after the condensate is discharged, it flows upward into the chimney 8 to leave the boiler.

[0038] Embodiment 2, as Figure 4As shown, the gas steam boiler comprises a curved special-shaped tube 1, a standard water pipe 2, an upper header 3, a lower header 4, a burner 5, a condenser 6, a smoke shell 7, a chimney 8 and a controller. The curved special-shaped tube 1 and the standard water pipe 2 are arranged in a vertically staggered annular manner. The space surrounded by the annular tube row is the furnace. The adjacent heat exchange tubes are combined to form an axial gap channel evenly distributed along the circumference. The upper and lower ends of all heat exchange tubes are necked and extend into the upper header 3 and the lower header 4 respectively; the upper header 3 and the lower header 4 are annular headers; the upper header 3 is provided with a steam exhaust port, a safety valve, a water level gauge interface, a pressure gauge or a pressure sensor, and a burner installation panel; the lower header 3 is provided with a steam exhaust port, a safety valve, a water level gauge interface, a pressure gauge or a pressure sensor, and a burner installation panel; There are water inlet, sewage outlet, furnace condenser partition plate and water level gauge interface on the box 4; the top of the smoke shell 7 is connected to the bottom outer edge of the upper header 3, surrounding the curved special-shaped tube 1, standard water pipe 2 and lower header 4, and there is an annular space for flue gas flow between the smoke shell 7 and the curved special-shaped tube 1, standard water pipe 2 and lower header 4; the burner 5 is fixed on the burner mounting panel of the upper header 3, and the lower end of the condenser 6 is flush with the upper surface of the lower header 4, which is used to condense the flue gas entering from the annular space; the condensate collecting tray 71 of the smoke shell 7 is located outside the condenser 6; the chimney 8 is located at one end of the condensate collecting tray 71, away from the outside of the upper header 3.

[0039] The curved special-shaped tube 1 adopts a single-sided concave tube 101 or a second double-sided concave tube 103; in particular, when the single-sided concave tube 101 is adopted, the standard water pipe 2 is not required, the single-sided concave tubes 101 are arranged in a ring, and axial gap channels evenly distributed along the circumference are formed between adjacent tubes.

[0040] After being evenly mixed at the front end of the burner 5, the natural gas and air enter the furnace from top to bottom for combustion. The flue gas generated by the combustion enters the axial gap channel formed by the staggered arrangement of the curved special-shaped tubes 1 and the standard water pipes 2 under the joint constraints of the burner installation panel and the lower header partition plate. After the flue gas is cooled in the gap channel, it enters the annular space between the smoke shell 7 and the annular tube row, and then enters the annular space in the condenser 6 through the smoke shell 7 for condensation and cooling. The condensed flue gas enters the smoke shell 7 and the condensate collection tray 71 in turn, and after the condensate is discharged, it flows upward into the chimney 8 and leaves the boiler; the boiler feed water first enters the condenser 6 to absorb the waste heat of the flue gas, and then enters the lower header 4 to be evenly distributed to each curved special-shaped tube 1 and the standard water pipe 2. While flowing upward, it absorbs heat and vaporizes into water vapor, rises to the upper header 3, and leaves the boiler from the exhaust port of the upper header.

[0041] like Figure 5a , Figure 5b and Figure 5cAs shown, the gas steam boiler includes a curved special-shaped tube 1, a standard water pipe 2, an upper header 3, a lower header 4, a burner 5, a condenser 6, a smoke shell 7, a chimney 8, an embedded smoke pipe 9, a partition 10, an outer circle upper water chamber 11, an outer circle lower water chamber 12, an outer circle water pipe 13 and a smoke collecting box 14. An inner ring tube row and an outer ring tube row are provided. The inner ring tube row is composed of curved special-shaped tubes 1 and standard water tubes 2 arranged in a vertically staggered ring. The space enclosed by the ring tube row is the furnace. Adjacent heat exchange tubes are combined to form axial gap channels evenly distributed along the circumference. Embedded smoke tubes 9 that penetrate the outer side of the furnace from top to bottom are provided in the curved special-shaped tubes 1 and the standard water tubes 2. The ends of the embedded smoke tubes 9 are corner-welded to the intersection lines of the outer sides of the curved special-shaped tubes 1 and the standard water tubes 2. The welded partitions 10 on the outer side of the formed ring tube row force the smoke to enter the embedded smoke tubes 9. The outer ring tube row includes an outer water tube 13, which is arranged around the inner ring tube row. The two ends of the outer water tube 13 are respectively connected to an upper water chamber 11 and a lower water chamber 12. The upper water chamber 11 is concentrically arranged close to the upper header 3, and the lower water chamber 12 is concentrically arranged close to the lower header 4. A partition is arranged in the upper water chamber 11 and the lower water chamber 12 to force the boiler feed water to flow back and forth between the upper water chamber 11 and the lower water chamber 12, so as to increase the flow velocity on the water side in the tube and reduce supercooled boiling; annular steel plates are arranged on the inner and outer sides of the outer ring tube row, and the upper end of the inner ring steel plate flows out of the flue gas channel, and the lower end of the outer ring steel plate flows out of the flue gas channel. The radial distance between the annular steel plate and the outer ring tube row is less than 5mm, forming a gap heat exchange area for the flue gas to pass through, so that the flue gas coming out of the upper end outlet of the embedded smoke tube 9 and the gap between the outer water tube are laminarly exchanged, thereby improving the condensation effect; The curved special-shaped tube 1 adopts a first double-sided inner concave tube 102 or a third double-sided inner concave tube 104 .

[0042] After being evenly mixed at the front end of the burner 5, the natural gas and air enter the furnace from top to bottom for combustion. The smoke generated by the combustion enters the axial gap channel formed by the staggered arrangement of the curved special-shaped pipe 1 and the standard water pipe 2 under the joint constraints of the burner installation panel and the lower header partition plate. After the smoke is cooled in the gap channel, it is forced to enter the embedded smoke pipe 9 from the lower end of the embedded smoke pipe 9 under the action of the partition 10 to flush the inner surface of the embedded smoke pipe 9, turn and flow downward from the upper end outlet of the embedded smoke pipe 9, and flow between the outer ring water pipe 13 and the outer ring water pipe 13. After being cooled and condensed in the gap channels between the inner and outer annular steel plates of the annular tube row and between the outer circle water pipes 13, the flue gas enters the flue gas collecting box 14, and the gathered flue gas is discharged from the chimney 8; the boiler feed water first enters the upper water chamber 11 and the lower water chamber 12 to absorb the waste heat of the flue gas, and then enters the lower header 4 to be evenly distributed to each curved special-shaped tube 1 and the standard water pipe 2, while absorbing heat and vaporizing into water vapor while flowing upward, rising to the upper header 3, and leaving the boiler from the exhaust port of the upper header 3.

[0043] like Figure 6a , Figure 6b , Figure 6c and Figure 6d As shown, the curved special-shaped tube 1 is a single-sided concave tube 101, a first double-sided concave tube 102, a second double-sided concave tube 103 or a third double-sided concave tube 104. The curved special-shaped tube 1 is evenly distributed along the circumferential direction to form a circle of annular tube rows. When the boiler power increases, two, three or four circles of annular tube rows can also be used to increase the heat exchange area. like Figure 6a As shown, the unilateral concave tube 101 is an arc-shaped tube with a unilateral extrusion depth of no more than 1 / 4 of the diameter. The unilateral concave tubes 101 with the same diameter are arranged vertically in a ring shape, and adjacent unilateral concave tubes 101 form a tile-like gap channel with a width of 0.1-4 mm. like Figure 6b As shown, the first double-sided inner concave tube 102 is an arc-shaped tube with a depth of no more than 1 / 4 of the diameter on both sides. The first double-sided inner concave tube 102 has the same diameter as the standard water pipe 2. The first double-sided inner concave tube 102 and the standard water pipe 2 are arranged in a vertically staggered circular arrangement. Adjacent first double-sided inner concave tubes 102 and standard water pipes 2 form a tile-like gap channel with a width of 0.1-4 mm. like Figure 6c As shown, the second double-sided inner concave tube 103 is an arc shape with a depth of no more than 1 / 4 of the diameter of the circular tube on both sides. The second double-sided inner concave tube 103 is 1 to 2.5 times larger than the diameter of the standard water pipe 2. The second double-sided inner concave tube 103 and the standard water pipe 2 are arranged in a vertically staggered circular arrangement, and the adjacent first double-sided inner concave tube 102 and the standard water pipe 2 form a tile-like gap channel with a width of 0.1 to 4 mm. like Figure 6d As shown, the third double-sided concave tube 104 is an arc-shaped square steel tube with a depth of no more than 1 / 4 of the diameter on both sides. The square steel can be square or rectangular. The length and width of the third double-sided concave tube 104 are 0.5~2.5 times the diameter of the standard water pipe 2. The third double-sided concave tube 104 and the standard water pipe 2 are vertically staggered and arranged in a ring. Adjacent third double-sided concave tubes 104 and standard water pipes 2 form a tile-like gap channel with a width of 0.1~4mm.

[0044] like Figure 7 As shown, the steel-aluminum composite inner wing tube 91 adopts the process of extruding aluminum, and has an interference fit with the embedded smoke tube 9 and the smoke tube 10. The inner wing of the steel-aluminum composite inner wing tube 91 can be an axisymmetric wing, a radial wing, a center-symmetric wing, etc. Further, it can also be an extruded aluminum inner wing type; the inner aluminum wing fins are center-symmetric, and the fins are composed of Y-shaped long and short wings. Through reasonable flow channel arrangement, heat transfer is further enhanced to achieve efficient heat exchange.

[0045] like Figure 8a and Figure 8bAs shown in the figure, the externally-mounted boiler slit-type coil condenser 61 is composed of special-shaped coils and standard coils. The special-shaped coils are composed of coils with single-sided or double-sided concave surfaces. The special-shaped coils and the standard coils are arranged alternately to form a slit channel for flue gas to pass through. At the same time, the steel plate attached to the coil is provided with a concave-convex structure adapted to the coil, forming a slit flue gas channel composed of the coil and the steel plate to prevent the flue gas corridor.

[0046] The flue gas enters the flue gas inlet in the circumferential direction inside the condenser 6 from the upper end outlet of the embedded flue pipe 9 and is evenly distributed to each slit channel. After the flue gas is condensed and cooled, it carries the condensed water and enters the smoke shell 7 and the condensed water collecting tray 71 in sequence. The boiler feed water flows in from the bottom water inlet of the externally-mounted boiler slit-type coil condenser 61 and flows out from the top water outlet, exchanging heat with the flue gas in countercurrent.

[0047] Specifically, the externally-mounted boiler slit-type coil condenser 61 can be formed by splicing two semi-circular externally-mounted boiler slit-type coil condensers 611, which facilitates the assembly of the outer circle of the boiler. The outer circle tube row and the externally-mounted condenser of the boiler can both be designed as semi-circular structures for matching installation.

[0048] As Fig. 9 shown in the figure, the bottom boiler slit-type coil condenser 62 is composed of special-shaped coils and coils. The special-shaped coils are composed of coils with single-sided or double-sided concave surfaces. The special-shaped coils and the standard coils are arranged alternately to form a slit channel for flue gas to pass through. At the same time, the steel plate attached to the coil of the condenser is provided with a concave-convex structure adapted to the coil, forming a slit flue gas channel composed of the coil and the steel plate to prevent the flue gas corridor.

[0049] The flue gas enters the circumferential flue gas inlet from the annular space between the smoke shell 7 and the lower header 4 and is evenly distributed to each slit channel. After the flue gas is condensed and cooled, it carries the condensed water and enters the condensed water collecting tray 71 from the bottom outlet tray. The boiler feed water flows in from the bottom water inlet of the bottom boiler slit-type coil condenser 62 and flows out from the top water outlet, exchanging heat with the flue gas in countercurrent. When the bottom boiler slit-type coil condenser 62 is used alone, it can also act as a coil steam generator.

[0050] As Fig.10a and Fig.10bAs shown, the slit-type straight tube condenser 63 includes a condenser upper water chamber, a condenser lower water chamber, a tube row arranged between the condenser upper water chamber and the condenser lower water chamber, an air duct inlet 631 arranged outside the annular tube row, and a bottom outlet annular disc 632 inside the condenser lower water chamber. The tube row is formed by vertically and alternately arranging curved special-shaped tubes 1 and standard water pipes 2 in a ring shape. Flue gas enters the air duct inlet 631 arranged outside the annular tube row from the annular space between the flue gas shell 7 and the lower header 4, is evenly distributed to each slit channel, enters the cavity formed by the curved special-shaped tube 1 and the standard water pipe 2 after condensation and cooling, and then enters the condensate collection tray 71 at the bottom of the flue gas shell 7 together with the condensate water from the bottom outlet tray; partitions are arranged in the condenser upper water chamber and the condenser lower water chamber to force the boiler feed water to flow reciprocally up and down between the condenser upper water chamber and the condenser lower water chamber, so as to increase the water-side flow velocity in the tube and reduce subcooled boiling.

[0051] The above content is only to illustrate the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A gas steam boiler with gap-enhanced heat transfer constructed by using a special-shaped tube curved surface, characterized in that: A boiler is arranged vertically, comprising an annular tube row, an upper header (3), and a lower header (4); the curved special-shaped tubes (1) are spaced from the standard water tubes (2) or the curved special-shaped tubes (1) are arranged in a circular pattern to form an annular tube row; there are tile-type gap channels between adjacent curved special-shaped tubes (1) or between the curved special-shaped tubes (1) and the standard water tubes (2); the space enclosed by adjacent annular tube rows is a furnace; the two ends of the curved special-shaped tubes (1) are connected to the upper header (3) and the lower header (4); the curved special-shaped tubes (1) and the standard water tubes (2) are connected to each other; An embedded smoke pipe (9) is provided, the inlet and outlet of the embedded smoke pipe (9) are oriented toward the outside of the boiler, and a steel-aluminum composite inner fin tube (91) is coupled inside the embedded smoke pipe (9); a partition plate (10) is welded outside the annular tube row, and a gap for smoke to pass through is formed between the partition plate (10) and the annular tube row, and the gap gradually decreases from top to bottom; the outlet of the embedded smoke pipe (9) is connected to a condenser (6), and the area where the furnace is located is wrapped with a smoke shell (7), and an annular space for smoke to flow exists between the smoke shell (7) and the heat exchange tube and the lower header (4).

2. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1 is characterized in that: It also includes a burner (5) installed on the upper header (3), the burner (5) is a diffusion burner or a full premix burner; the upper header (3) and the lower header (4) are both annular, and the burner (5) is installed on the inner side of the upper header (3).

3. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1 is characterized in that: The curved special-shaped tube (1) is a single-sided concave tube (101), a first double-sided concave tube (102), a second double-sided concave tube (103) or a third double-sided concave tube (104); the single-sided concave tube (101) is a circular tube with a single side pressed out to a circular arc shape of no more than 1 / 4 of the diameter; the first double-sided concave tube (102) is a circular tube with both sides pressed out to a circular arc shape of a set depth, and the first double-sided concave tube (102) has the same diameter as the standard water pipe (2); the second double-sided concave tube (103) is a circular tube with a single side pressed out to a circular arc shape of a set depth; The circular tube is pressed out of both sides into an arc shape with a set depth, and the second double-sided inner concave tube (103) is 1 to 2.5 times larger than the diameter of the standard water pipe (2); the third double-sided inner concave tube (104) is pressed out of both sides into an arc shape with a set depth, and the square steel can be square or rectangular, and the length and width of the third double-sided inner concave tube (104) are 0.5 to 2.5 times the diameter of the standard water pipe (2); and an embedded smoke pipe (9) is provided in the first double-sided inner concave tube (102) and the third double-sided inner concave tube (104).

4. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1 is characterized in that: The annular pipe row is arranged in two, three or four circles; when the annular pipe row is arranged in two circles, the inner annular pipe row is formed by vertically staggered annular arrangement of curved special-shaped pipes (1) and standard water pipes (2); the outer annular pipe row includes an outer water pipe (13), which is arranged around the inner pipe row, and the two ends of the outer water pipe (13) are respectively connected to an upper water chamber (11) and a lower water chamber (12), and the upper water chamber (11) is arranged concentrically and closely with the upper header (3). The lower water chamber (12) is arranged concentrically and closely with the lower header (4); partitions are arranged in the upper water chamber (11) and the lower water chamber (12) to force the boiler feed water to flow back and forth between the upper water chamber (11) and the lower water chamber (12); annular steel plates are arranged on the inner and outer sides of the outer ring pipe row, the upper end of the inner ring steel plate flows out of the flue gas channel, and the lower end of the outer ring steel plate flows out of the flue gas channel, and the radial distance between the annular steel plate and the outer ring pipe row is less than 5 mm.

5. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1 is characterized in that: The condenser (6) is configured as a boiler external slotted coil condenser (61) or a boiler bottom slotted coil condenser (62); when the boiler external slotted coil condenser (61) is configured at the upper portion, the top end of the boiler external slotted coil condenser (61) is flush with the lower surface of the upper header (3); when the boiler external slotted coil condenser (61) is configured at the lower portion, the lower end of the boiler external slotted coil condenser (61) is flush with the upper surface of the lower header (4); the boiler bottom slotted coil condenser (62) is configured below the lower header (4).

6. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1 is characterized in that: The boiler external slotted tube coil condenser (61) is composed of two semicircular external slotted tube coil condensers (611).

7. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1 is characterized in that: The condenser (6) is a coil-type condenser, wherein the coil is composed of a combination of a special-shaped coil and a standard coil, the special-shaped coil is composed of a coil with a single or double-sided inward concave shape, the special-shaped coil and the standard coil are arranged alternately to form a gap channel for smoke to pass through, a steel plate fitted with the coil is provided with a concave-convex structure adapted to the coil, forming a gap smoke channel formed by the coil and the steel plate, and the smoke inlet smoke coil of the condenser (6) is arranged circumferentially.

8. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1 is characterized in that: The steel-aluminum composite inner wing tube (91) is produced by extruding aluminum and is interference-fitted with the embedded smoke tube (9) and the smoke tube (10). The inner wing of the steel-aluminum composite inner wing tube (91) is an axisymmetric wing, a radial wing, or a centrosymmetric wing.

9. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1, characterized in that: The condenser (6) adopts a slot-type straight tube condenser (63), which comprises an upper water chamber of the condenser, a lower water chamber of the condenser, a tube row arranged between the upper water chamber of the condenser and the lower water chamber of the condenser, an air duct inlet (631) arranged outside the annular tube row, and a bottom outlet annular plate (632) on the inner side of the lower water chamber of the condenser, wherein the tube row is formed by a vertically staggered annular arrangement of curved special-shaped tubes (1) and standard water tubes (2); partitions are arranged in the upper water chamber of the condenser and the lower water chamber of the condenser to force boiler feed water to flow back and forth between the upper water chamber and the lower water chamber.

10. The gas steam boiler with gap-enhanced heat transfer constructed by using special-shaped tube curved surface according to claim 1, characterized in that: The width of the tile-type gap channel is 0.1~4mm.

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