Gas steam generator of vertical water pipe embedded smoke pipe enhanced heat transfer element

Abstract

The invention discloses a gas steam generator of a vertical water pipe embedded smoke pipe enhanced heat transfer element, two circles of vertical water pipes embedded with smoke pipes are welded between an upper annular header and a lower annular header, and inlets and outlets of the inner circle of smoke pipes are arranged on the outer sides of the water pipes, so that direct radiation of flames and high-temperature smoke is avoided. And flat steel is welded at the middle upper part of the inner ring water pipe to form a membrane type water cooling wall. An inlet and an outlet of the outer-ring smoke pipe are located on the two sides of the water pipe and are opposite to an outlet of the inner-ring smoke pipe. The top-mounted gas burner completely burns in the membrane type wall hearth, and generated high-temperature smoke flows downwards from gaps without flat steel, then is gathered under the action of a shell plate, enters the embedded steel-aluminum composite smoke pipe, flows upwards to a smoke pipe outlet and then enters the outer-ring steel-aluminum composite smoke pipe to be cooled and condensed. And water is directly heated from the lower part of the smoke pipe and discharged. The smoke pipe of the heat transfer element does not directly bear flame radiation, the water capacity of the water pipe embedded with the smoke pipe is extremely small, and integrated low-carbon low-resistance safe and efficient heat exchange is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of steam generators, and particularly to a gas steam generator with a vertical water pipe embedded with a smoke pipe and a heat transfer element for enhancing heat transfer. Background Art

[0002] A vertical steam generator, also known as a steam heat source machine or a boiler, is a heat energy conversion device that can heat water into steam and can meet a large amount of heat energy requirements. This device can provide a stable and reliable steam heat energy supply, and at the same time has the advantages of energy conservation and environmental protection. With the increasingly prominent energy problem, the current development of steam generators pays more attention to energy conservation and high efficiency. By improving the equipment structure of the steam generator and adopting the technology of nesting a smoke pipe inside a water pipe, the water volume in the steam generator can be significantly reduced, the heat loss caused by frequent start and stop can be significantly reduced, and the quality, performance and safety of the steam generator can be ensured, thereby guaranteeing the service life and reliability of the equipment, improving the energy utilization rate and reducing energy consumption.

[0003] At present, the heat transfer element structure of the vertical gas boiler with a smoke pipe embedded in the water pipe on the market is not mature. For example, the vertical gas boiler of CN219473621U applied by Chongqing Taihu Boiler Co., Ltd. adopts a heat transfer element structure with smoke pipes penetrating through the inner and outer parts of the furnace vertically in the water pipe. This heat transfer element structure has many problems, among which there are serious potential safety hazards: (1) The inner surface of the water pipe located in the furnace bears strong radiation heat transfer. The smoke pipes penetrate through both sides of the inner and outer water pipes in the furnace. The inner surface area of the water pipe is small, and the heat transfer in the furnace is limited. The temperature of the furnace flame and the high-temperature flue gas above 1300 °C is extremely high. The pipe end of the smoke pipe welded on the inner side of the water pipe is close to the burner flame. On the one hand, when a diffusion burner is selected, natural gas enters the smoke pipe directly without being fully burned, resulting in fuel waste; on the other hand, the pipe end of the smoke pipe welded on the inner side of the water pipe bears strong flame and high-temperature flue gas radiation heat transfer. Coupled with the inlet enhanced convective heat transfer effect when the high-temperature flue gas above 1300 °C enters the pipe end of the smoke pipe, the local heat load is extremely high, the local heat flux density is extremely large, and the pipe end of the smoke pipe and the water pipe are connected by fillet welding with a saddle-shaped intersection line with uneven heights, which is prone to overheating and causing cracking and leakage accidents at the pipe end of the smoke pipe. (2) The pipe end of the smoke pipe welded to the water pipe is a 90° elbow structure. The inner water space where the elbow and the water pipe are connected is in a violent boiling state, and scale or crevice corrosion is easy to form inside the fillet weld at the connection, which may cause local overheating and even cracking and leakage. The operation practice of these furnace types over the years fully verifies the above theoretical analysis results. Summary of the Invention

[0004] In order to solve the problems existing in vertical gas steam generators, the present invention aims to provide a gas steam generator with a smoke pipe enhanced heat transfer element embedded in a vertical water pipe, constructing a heat transfer element embedded in the water pipe and penetrating the smoke pipe outside the furnace from top to bottom. The smoke pipe end is only connected to the intersection line outside the water pipe by fillet welding, and no longer bears direct flame and high-temperature smoke radiation. The local heat load and local heat flux density are greatly reduced. The only heat load is less than 800°C smoke temperature after passing through the lower end or bottom of the water pipe bundle and the 360° radial gap laminar flow enhanced convection heat exchange along the circumference. This not only completely eliminates and avoids the possibility that the fillet welding connection between the smoke pipe end and the outside of the water pipe may be damaged due to local Overheating and even cracking and leakage are avoided, and low-resistance laminar flow is used to enhance efficient heat exchange; the end of the smoke pipe welded to the water pipe is a small-angle elbow structure, which avoids the 90-degree elbow structure where the inner water space connected to the elbow and the water pipe is in a violent boiling state, and the inside of the corner weld at the connection is prone to scaling or crevice corrosion, which causes local overheating and even cracking and leakage, ensuring the stable, efficient and corrosion-resistant operation of the steam generator; the water pipe is nested in the smoke pipe to significantly reduce the water volume in the steam generator and improve the thermal efficiency of steam; the design of the energy-saving condensing water tank on the outer jacket of the smoke pipe saves the area of ​​the external condenser and improves the space utilization rate. As a result, the steam generator has full combustion, high space utilization rate, and small footprint, realizing integrated low-carbon, low-resistance and high-efficiency heat exchange.

[0005] In order to achieve the above object, the technical scheme adopted by the present invention is: a gas steam generator with a vertical water pipe embedded smoke pipe enhanced heat transfer element, comprising an upper header, a lower header, a smoke baffle, an upper water chamber, a lower water chamber, a smoke exhaust pipe, and inner and outer annular pipe rows. The inner pipe row and the outer pipe row are both formed by arranging a circle of vertical water pipes. The inner vertical water pipe has an inner embedded smoke pipe. The inlet and outlet of the inner embedded smoke pipe are arranged outside the vertical water pipe. The upper middle part of the inner vertical water pipe is a membrane water cooling wall. The lower part of the inner vertical water pipe is a membrane water cooling wall. A flue gas gap channel is left in the inner circle; a flue gas baffle is welded on the lower outer side of the inner circle tube row; an outer circle embedded smoke pipe is arranged in the outer circle vertical water pipe, and the outer circle vertical water pipes are closely arranged in a circle, and the inlet and outlet of the outer circle embedded smoke pipe are respectively located on both sides of the outer circle vertical water pipe, the inlet is opposite to the outlet of the inner circle embedded smoke pipe, and the outlet is connected to the smoke exhaust pipe; the two ends of the inner circle vertical water pipe are respectively connected to the upper header and the lower header; the two ends of the outer circle vertical water pipe are respectively connected to the upper water chamber and the lower water chamber, and the embedded smoke pipe is a steel-aluminum composite inner fin tube enhanced heat exchange structure.

[0006] Furthermore, baffles are arranged in the upper water chamber and the lower water chamber to guide the boiler feed water to flow back and forth up and down between the upper water chamber and the lower water chamber; the upper water chamber and the lower water chamber are respectively composed of two independent half circles spliced ​​together.

[0007] Further, a burner is provided at the top, and both the upper header and the water inlet chamber are annular; the upper header is arranged inside the water inlet chamber; a central symmetry design is adopted, and the burner is a diffusion burner or a metal fiber surface burner, and the burner is arranged inside the upper header. The upper header is a U-shaped header up and down, and the U-shaped header up and down uses U-shaped lower corner rings with different lengths at both ends to be buckled, and two circumferential welds are welded; or a U-shaped welded angle steel header using a U-shaped lower corner ring welded to an angle steel can be adopted; or a plate-edge rectangular header welded by plate-edge rectangular buckling can be adopted; or a lower U-shaped upper triangular header can be adopted; the lower header adopts the same structural form as the upper header. The upper header is a U-shaped header up and down, and the U-shaped header up and down uses U-shaped lower corner rings with different lengths at both ends to be buckled, and two circumferential welds are welded; or a U-shaped welded angle steel header using a U-shaped lower corner ring welded to an angle steel can be adopted; or a plate-edge rectangular header welded by plate-edge rectangular buckling can be adopted; or a lower U-shaped upper triangular header can be adopted; the lower header adopts the same structural form as the upper header.

[0008] Further, in the inner row of tubes, flat steel is welded to the upper part between adjacent vertical water tubes to form a membrane water wall, and the flat steel extends to the upper end of the flue gas gap channel; the width of the flat steel does not exceed mm, and the length of the flat steel is one-fourth shorter than the length of the vertical water tube.

[0009] Further, the tube ends of the inner embedded flue tubes are only connected by fillet welding at the intersection line with the outer side of the vertical water tubes.

[0010] Further, the inner embedded flue tube is a steel-aluminum composite inner finned tube, and the steel-aluminum composite inner finned tube is in interference fit with the inner embedded flue tube. The inner fins of the steel-aluminum composite inner finned tube are axisymmetric fins, radial fins or centrally symmetric fins, or the inner fins of the steel-aluminum composite inner finned tube adopt an extruded aluminum inner fin type; a part of the extruded aluminum inner fin type rotates by a set angle, or fins with a set length are removed in the middle of the steel-aluminum composite inner finned tube; Or the inside of the inner embedded flue tube adopts a combination of an internal threaded tube and a steel-aluminum composite inner finned tube, with the upper half using an internal threaded tube and the lower half using a steel-aluminum composite inner finned tube.

[0011] A gas steam generator with a vertical water tube inner embedded flue tube enhanced heat transfer element is also provided, including an upper header, a lower header, a flue gas baffle, a water inlet chamber, a water outlet chamber, a smoke exhaust pipe and two inner and outer annular tube rows. The inner row of tubes is formed by arranging vertical water tubes in a circle. There are inner embedded flue tubes in the vertical water tubes in the inner circle. The upper part of the vertical water tubes in the inner circle is a membrane water wall, and a flue gas gap channel is left at the lower part of the vertical water tubes in the inner circle; the inner embedded flue tube is a steel-aluminum composite inner finned tube enhanced heat transfer structure, and the outer side of the vertical water tube is coupled with fins for enhanced heat transfer. The outer row of tubes uses flue tubes arranged circumferentially instead of vertical water tubes. An energy-saving condensation water tank is arranged outside the flue tubes, and fins are coupled inside the flue tubes; the outlet of the inner embedded flue tube in the inner circle and the inlet of the flue tube are welded at the bottom end. The flue tube outlet is connected to the smoke exhaust pipe, and the inner row of tubes and the outer row of tubes are separated by a steel plate.

[0012] Furthermore, the lower end opening of the smoke pipe is connected to a drain pipe, the drain pipe is connected to a condensate collection chamber, the condensate collection chamber is arranged at the bottom of the vertical gas-fired steam generator, the upper end of the energy-saving condensate water tank takes in water and the lower end discharges water, and it exchanges heat countercurrently with the upward flowing flue gas; the discharged water enters the lower header to preheat the boiler feed water; a spiral plate structure is arranged in the energy-saving condensate water tank, and the water flow descends in a spiral manner.

[0013] Furthermore, the energy-saving condensate water tank is replaced by an energy-saving condensate water sleeve. The two ends of the energy-saving condensate water sleeve are respectively connected to an upper water chamber and a lower water chamber. Partition plates are arranged in the upper water chamber and the lower water chamber to force the water circulation, and a heat exchange by condensation is carried out by sleeving the energy-saving condensate water sleeve outside the smoke pipe; the energy-saving condensate water tank and the energy-saving condensate water sleeve are arranged as a whole by splicing two half circles.

[0014] Furthermore, the lower part of the steel plate adopts a Cr25Ni20Si2 alloy material, and the upper half part adopts a 12Cr1MoV alloy material; refractory cotton is laid between the energy-saving condensate water tank and the steel plate; refractory materials are laid between the upper header and the lower header and the inner ring tube row. Compared with the prior art, the present invention has at least the following beneficial effects: The present invention innovatively constructs a heat transfer element with water pipes embedded with smoke pipes penetrating through the outside of the furnace from top to bottom. The pipe ends of the smoke pipes are only connected to the water pipes by fillet welding along the intersection line on the outside of the water pipes, and no longer bear the direct flame and high-temperature flue gas radiation. The local heat load is greatly reduced, the local heat flux density is greatly decreased, and it only bears the flue gas temperature below 800 °C after passing through the lower end or bottom of the water pipe bundle and being strengthened by laminar convection heat transfer in the 360° circumferential radial clearance layer. It completely eliminates and avoids the possible faults of local overheating or even cracking and leakage at the fillet welding connection between the pipe ends of the smoke pipes and the outside of the water pipes, and realizes low-resistance laminar flow enhanced high-efficiency heat transfer.

[0015] Furthermore, the pipe ends of the smoke pipes welded to the water pipes are of a small-angle elbow structure, which avoids the situation that the inner water space at the connection between the elbow and the water pipe in the 90-degree elbow structure is in a violent boiling state, and it is easy to form scale or crevice corrosion on the inner side of the fillet weld at the connection, thus causing local overheating and even cracking and leakage, and ensuring the stable, efficient and corrosion-resistant operation of the steam generator.

[0016] Furthermore, smoke pipes are nested inside the water pipes, significantly reducing the water volume in the steam generator and improving the steam thermal efficiency. The inner ring tube row adopts sub-pipes nested inside the water pipes to strengthen heat transfer. The high-temperature flue gas contacts the water pipes and transfers energy to the water pipes. At the same time, the flue gas flows into the embedded smoke pipes inside the water pipes and then flows out from the bottom of the embedded smoke pipes. This sub-pipe and water pipe form a mother-and-son type high-efficiency heat exchange structure, increasing the travel of the flue gas, improving the heat transfer capacity inside and outside the pipes, improving the steam discharge efficiency, and thus ensuring the steam utilization rate.

[0017] Furthermore, the header uses U-shaped lower corner rings with different lengths at both ends to be butted and welded with two circumferential welds; alternatively, a U-shaped welded angle steel header with a U-shaped lower corner ring welded to an angle steel can be used; alternatively, a plate-edge rectangular header with plate-edge rectangular butted welding can be used; or a lower U-shaped and upper triangular header can be used. Compared with traditional headers, the pressure-bearing capacity is enhanced while the number of welds is reduced.

[0018] Furthermore, the flue gas exhaust temperature of the main body of the traditional single-loop spiral finned tube steam generator drops by more than 50 °C. The design method of cascade enhanced heat transfer is adopted, that is, plate fins or pin fins are used in the high-temperature section, and aluminum inner fins are used in the medium and low-temperature sections to give full play to the heat transfer characteristics of different fins and materials.

[0019] Furthermore, the inner row of tubes adopts a design of a radial clearance channel at the lower end, and the high-temperature flue gas generated by the burner is discharged from the clearance channel below the inner row of tubes, providing a space for the full combustion of fuel, improving the utilization rate of materials and space and the heat transfer capacity of the device.

[0020] Furthermore, external coupling fins on the water pipes and internal coupling fins in the flue pipes are used for turbulent enhancement, and a new type of inner finned tube is proposed to enhance the heat transfer capacity inside the tube. Both the external finned tube and the internal finned tube adopt various fin forms and enhanced heat transfer methods, expanding the heat transfer area and optimizing the flue gas flow, greatly improving the heat transfer efficiency.

[0021] Furthermore, an energy-saving condensation water tank is designed outside the outer row of tubes to absorb the waste heat of the flue gas and preheat the feed water of the inner row of tubes, saving the occupied space required for an external condenser, and the occupied space of the boiler system can be reduced by 30% - 50%.

[0022] Furthermore, the gas steam generator with a vertical water pipe embedded with a flue pipe and a heat transfer enhancement element adopts a multi-pass counter-current heat exchange design to achieve full heat utilization, reduce the flue gas temperature to below 50 °C, reduce the water volume of the device, achieve multi-pass integrated low-carbon, low-resistance and high-efficiency heat exchange, and meet the actual use requirements. Brief Description of the Drawings

[0023] The invention will be described in detail below with reference to the drawings and specific embodiments.

[0024] Figure 1a is a vertical full-sectional schematic diagram of a gas steam generator with a vertical water pipe embedded with a flue pipe and a heat transfer enhancement element, Figure 1b is a horizontal half-sectional schematic diagram of the steam generator; Figure 1c is a schematic diagram of the flue gas flow direction of the steam generator.

[0025] Figure 2 is a schematic diagram of the welded flat steel of the water pipe and the flue gas flow direction.

[0026] Figure 3 is a schematic diagram of a steel-aluminum composite inner finned tube and the inner fin profile.

[0027] Figure 4a It is a schematic structural diagram of a part of a steel-aluminum composite pipe rotated by a certain angle. Figure 4b It is a schematic diagram of removing fins in a part of a steel-aluminum composite inner finned pipe to enhance heat transfer.

[0028] Figure 5 It is a schematic diagram of a flue pipe with an inner threaded pipe in the upper half and a steel-aluminum composite pipe in the lower half.

[0029] Figure 6a It is a schematic diagram of an upper header using an upper and lower U-shaped header. Figure 6b It is a schematic diagram of a U-shaped welded angle steel header. Figure 6c It is a schematic diagram of a rectangular header with a flanged edge. Figure 6d It is a schematic diagram of a lower U-shaped and upper triangular header.

[0030] Figure 7 It is a schematic diagram of a vertical gas steam generator using a top-mounted diffusion burner.

[0031] Figure 8a It is a vertical full-section schematic diagram of a gas steam generator with a vertical water pipe embedded with a flue pipe and enhanced heat transfer elements. Figure 8b It is a horizontal half-section schematic diagram of the steam generator; Figure 8c It is a schematic diagram of the flue gas flow direction of the steam generator.

[0032] Figure 9 It is a schematic diagram of a coupled fin structure on the outer side of a vertical water pipe.

[0033] Figure 10 It is a schematic diagram of a spiral plate structure built into an energy-saving condensate water tank.

[0034] Figure 11 It is a schematic diagram of an energy-saving condensate water casing.

[0035] In the attached drawings, 1 - burner, 101 - diffusion burner, 2 - upper header, 201 - upper and lower U-shaped header, 202 - U-shaped welded angle steel header, 203 - rectangular header with a flanged edge, 204 - lower U-shaped and upper triangular header, 3 - water pipe, 31 - outer fins of the water pipe, 4 - embedded flue pipe, 41 - inner ring embedded flue pipe, 42 - outer ring embedded flue pipe, 401 - steel-aluminum composite inner finned pipe, 4011 - steel-aluminum composite inner finned pipe rotated by a certain angle, 402 - inner threaded pipe, 5 - flat steel, 6 - lower header, 7 - flue gas baffle, 8 - upper water chamber, 9 - lower water chamber, 10 - flue gas shell, 11 - flue gas collection box, 12 - exhaust pipe, 13 - steel plate, 14 - refractory cotton, 15 - flue pipe, 16 - energy-saving condensate water tank, 161 - energy-saving condensate water casing, 17 - drain pipe, 18 - condensate water collection chamber. Detailed implementation manners

[0036] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0037] The present invention discloses a gas steam generator with a vertical water pipe embedded with a smoke pipe and a heat transfer strengthening element. A circle of vertical water pipes embedded with smoke pipes is welded between the upper and lower annular headers. The inlets and outlets of the smoke pipes are arranged outside the vertical water pipes, avoiding direct radiation from flames and high-temperature flue gas. Flat steel is welded in the upper and middle parts between the vertical water pipes to form a membrane water wall, and there is no flat steel in the lower part. The top-mounted gas burner burns completely in the membrane furnace chamber. The generated high-temperature flue gas turns downward by 180º and flows out from the gap without flat steel, then flushes the fins on the outside of the water pipe upward. When it reaches the top, the flue gas turns 180º again and enters the embedded steel-aluminum composite smoke pipe to flow downward. After reaching the outlet of the lower smoke pipe, it enters the outer vertical water pipe of the embedded steel-aluminum composite smoke pipe with the same structure as the inner ring water pipe. However, the outer water pipe directly heats the feed water, and after the flue gas is cooled and condensed, it converges and is discharged from the upper part of the smoke pipe. The inlets and outlets of the smoke pipes of the heat transfer element of the present invention do not bear flame radiation, and the water volume of the water pipe embedded with the smoke pipe is extremely small, which can achieve integrated low-carbon, low-resistance, safe and efficient heat exchange.

[0038] As shown in Figure 1, the vertical gas steam generator body includes a burner 1, an upper header 2, a lower header 6, a flue gas baffle 7, a water inlet chamber 8, a water outlet chamber 9, a flue gas shell 10, a flue gas collection box 11, an exhaust pipe 12, and two inner and outer annular tube rows. The two inner and outer annular tube rows are formed by arranging vertical water pipes 3 circumferentially. There is an embedded flue gas pipe 4 in the vertical water pipe 3, and the inlet and outlet of the embedded flue gas pipe 4 are opened on the pipe wall of the vertical water pipe 3. The inlet and outlet of the inner ring embedded flue gas pipe 41 are arranged outside the vertical water pipe 3 to avoid direct radiation of the flame and high-temperature flue gas. The upper and middle parts of the inner ring vertical water pipes 3 are membrane water walls, and a flue gas gap channel is left at the lower part of the inner ring vertical water pipes 3. The flue gas gap channel is one-fourth of the length of the vertical water pipe 3. In the inner ring tube row, flat steel 5 is welded to the upper part between adjacent vertical water pipes 3 to form a membrane water wall, and the flat steel 5 extends to the upper end of the flue gas gap channel. The embedded flue gas pipe 4 is a steel-aluminum composite inner finned tube for enhanced heat transfer. The outer ring vertical water pipes 3 are closely arranged in a circle. The inlet and outlet of the outer ring embedded flue gas pipe 42 are located on both sides of the outer ring vertical water pipes 3 respectively, and the inlet is opposite to the outlet of the inner ring embedded flue gas pipe 41. A flue gas baffle 7 is welded to the lower part outside the inner ring tube row; partitions are arranged in the water inlet chamber 8 and the water outlet chamber 9 to guide the boiler feed water to flow reciprocally up and down between the water inlet chamber 8 and the water outlet chamber 9, so as to increase the water side flow velocity in the pipe and reduce subcooled boiling; both ends of the outer ring vertical water pipes 3 are respectively connected to the water inlet chamber 8 and the water outlet chamber 9. The water inlet chamber 8, the water outlet chamber 9, and the outer ring tube row form an outer ring energy-saving condenser, which can be used independently in half circles and is composed of two left and right half circles spliced together, solving the problem that it is difficult to sleeve the outer ring tube row outside the inner ring tube row. The burner 1 is arranged at the top and is a gas burner. After the burner 1 burns completely in the membrane furnace chamber, the generated high-temperature flue gas flows downward from the lower flue gas gap channel of the inner ring tube row, and after being collected by the flue gas baffle 7, the flue gas enters the inner ring embedded flue gas pipe 41, flushes the surface of the inner fins upward until the outlet of the inner ring embedded flue gas pipe 41, then enters the outer ring embedded flue gas pipe 42 for cooling and condensation, directly heats the feed water of the outer ring water pipes 3, and then converges from the lower outlet of the outer ring embedded flue gas pipe 42, enters the flue gas collection box 11 and is discharged into the atmosphere through the exhaust pipe 12. Flat steel 5 is welded to the upper part between adjacent vertical water pipes 3 in the inner ring tube row to form a membrane water wall, and a flue gas gap channel is left at the upper and lower ends between adjacent vertical water pipes 3 for the flue gas to flow out. The pipe ends of the inner ring embedded flue gas pipe 41 are only connected by fillet welding at the intersection line with the outside of the vertical water pipe 3 and do not bear direct flame and high-temperature flue gas radiation. The upper end of the outer ring embedded flue gas pipe 41 is the flue gas inlet, and a steel-aluminum composite inner finned tube 401 is coupled inside the pipe. Refractory material 12 is laid at the centers of the upper header 2 and the lower header 6; there are an exhaust port, a safety valve, a water level gauge interface, a pressure gauge or a pressure sensor, and a burner installation panel on the upper header 2; there are a water inlet, a blowdown port, a furnace condenser partition plate, and a water level gauge interface on the lower header 6.

[0039] As Figure 2As shown, the width of the flat steel 5 does not exceed 6 mm. The length of the flat steel 5 is one-fourth shorter than the length of the vertical water pipe 3. It is welded to the adjacent vertical water pipe 3 and arranged in a circular pattern. A flue gas gap channel is left at the lower part between the adjacent vertical water pipes 3. The flue gas flows out from the flue gas gap channel, forming a laminar flow enhanced heat transfer zone, which enhances the heat transfer capacity outside the steam evaporator tubes.

[0040] As Figure 3 shown, a steel-aluminum composite inner finned tube 401 can be used inside the embedded flue gas pipe 4. It has an interference fit with the embedded flue gas pipe 4 to enhance the heat transfer capacity. The inner fins of the steel-aluminum composite inner finned tube 401 can be axisymmetric fins, radial fins or centrosymmetric fins. An extruded aluminum inner fin type can also be used. The inner aluminum fins are centrosymmetric, and the fins are composed of Y-shaped long and short fins. Through reasonable flow channel arrangement, heat transfer is further enhanced to achieve efficient heat exchange.

[0041] As Figure 4a and Figure 4b shown, further, a part of the steel-aluminum composite tube 401 can be rotated by a set angle to enhance turbulent heat transfer, or a set length of fins can be removed from the middle of the steel-aluminum composite inner finned tube 401 to utilize the inlet and outlet effects to enhance heat transfer; As Figure 5 shown, inside the embedded flue gas pipe 4, an inner threaded tube 402 can also be combined with the steel-aluminum composite inner finned tube 401. When using a high-power steam generator, the upper half uses an inner threaded tube with strong high-temperature resistance, and the lower half uses a steel-aluminum composite inner finned tube with stronger heat transfer capacity.

[0042] As Figure 6a shown, the upper header 2 of the vertical gas-fired steam generator can adopt upper and lower U-shaped headers 201. The upper and lower U-shaped headers 201 are butted with U-shaped lower corner rings of different lengths at both ends and welded with two circumferential welds; or a U-shaped welded angle steel header 202 formed by welding a U-shaped lower corner ring with an angle steel can be adopted, refer to Figure 6b ; or a plate-edge rectangular header 203 formed by butt-welding plate edges can be adopted; or a lower U-shaped and upper triangular header 204 can be adopted, refer to Figure 6c and Figure 6d ; The lower header 6 can be adopted in the same way. While enhancing the pressure-bearing capacity of the header, the number of welds is reduced.

[0043] As Figure 7 shown, the vertical gas-fired steam generator adopts a centrosymmetric design. The flue gas in the furnace can be evenly distributed in the radial direction to each gap channel in the vertical direction, compatible with the mainstream diffusion-type burner 101 and metal fiber surface burner, solving the problems of single-sided flue gas exhaust, uneven heat load, and easy scaling and tube explosion in the furnace of traditional once-through boilers.

[0044] As Figure 8a 、 Figure 8b and Figure 8cAs shown in the figure, a vertical gas steam generator, the main body of which includes a burner 1, an upper header 2, a lower header 6, a smoke shell 10, an exhaust pipe 12, a flue gas collection box 11, an energy-saving condensate water tank 16, a condensate water collection chamber 18, and an inner and outer two-ring annular tube bank. The inner and outer two-ring annular tube banks are formed by arranging vertical water pipes 3 along the circumferential direction. There is an embedded smoke tube 4 in the vertical water pipe 3, and the inlet and outlet of the embedded smoke tube 4 are opened on the pipe wall of the vertical water pipe 3. The inlet and outlet of the inner ring embedded smoke tube 41 are arranged outside the vertical water pipe 3 to avoid direct radiation of the flame and high-temperature flue gas. The upper and middle parts of the inner ring vertical water pipe 3 are membrane water walls, and a flue gas gap channel is left at the lower part of the inner ring vertical water pipe 3. The flue gas gap channel is one-fourth of the length of the vertical water pipe 3, and the flat steel 5 extends to the upper end of the flue gas gap channel. The embedded smoke tube 4 is a steel-aluminum composite inner finned tube for enhanced heat transfer. The outer ring tube bank is formed by sleeving the smoke tube 15 with the energy-saving condensate water tank 16, and there are coupling fins in the smoke tube 15; the inner ring embedded smoke tube 41 and the smoke tube 15 are welded at the bottom to connect the inner and outer two-ring tube banks. The middle channel between the two tube banks is isolated by a steel plate 13, and refractory cotton 14 is laid between the steel plate 13 and the outer ring tube bank; refractory materials are laid at the centers of the upper header 2 and the lower header 6; there are an exhaust port, a safety valve, a water level gauge interface, a pressure gauge or a pressure sensor, and a burner installation panel on the upper header 2; there are a water inlet, a blowdown port, a furnace condenser partition plate, and a water level gauge interface on the lower header 6; the steel plate 13 separates the high-temperature flue gas from the outer ring smoke tube bank and the energy-saving condensate water tank 16. The lower part of the steel plate 13 has to withstand a high temperature of 1000 °C and is made of Cr25Ni20Si2 alloy material, and the upper half is made of 12Cr1MoV alloy material; refractory cotton 14 is laid between the energy-saving condensate water tank 16 and the steel plate 13 to prevent the energy-saving condensate water tank 16 from being burned out; refractory materials are laid between the upper and lower headers and the inner ring tube bank to prevent flue gas leakage.

[0045] There is a steel-aluminum composite inner finned tube 401 with strong heat transfer coupling in the smoke tube 15; the smoke tube 15 is externally nested with an energy-saving condensate water tank 16, and the lower end is open and connected to a drain pipe 17. The drain pipe 17 is connected to the condensate water collection chamber 18, and the condensate water collection chamber 18 is arranged at the bottom of the vertical gas steam generator; the lower end of the smoke tube 15 is bent 90 degrees and welded to the inner ring embedded smoke tube 41, and the upper end of the smoke tube 15 is bent 90 degrees and connected to the exhaust pipe 12. The flue gas enters the smoke tube 15 from the inner ring smoke tube 41, flows upward and flushes the inner surface of the smoke tube 15, exchanges heat with the energy-saving condensate water tank 16, then enters the flue gas collection box 11, and is discharged into the atmosphere through the exhaust pipe 12. The condensate water enters the condensate water collection chamber 18 through the drain pipe 17.

[0046] The top-mounted gas burner burns completely in the membrane-type fireplace chamber. After the generated high-temperature flue gas turns downward by 180º and flows out from the gap without flat steel, it flushes upward along the outer fins of the water pipes. When it reaches the top, the flue gas turns by 180º again and enters the inner-ring embedded smoke pipe 41 and flows downward. After reaching the lower smoke pipe outlet, it enters the outer vertical water pipes of the embedded steel-aluminum composite smoke pipe with the same structure as the inner-ring water pipes. However, the outer water pipes directly heat the feed water, and after the flue gas cools and condenses, it converges and is discharged from the upper part of the smoke pipe.

[0047] As Figure 9 shown, the outer side of the vertical water pipe 3 is coupled with fins to enhance heat transfer. A smoke pipe is arranged inside the vertical water pipe 3, and the outer side of the vertical water pipe 3 is coupled with fins 31 to enhance heat transfer. The fins 31 can be straight fins, bent fins, tapered fins, or wavy fins. Inner fins 401 are coupled inside the inner smoke pipe 41, and a combination forms internal and external heat transfer enhancement elements.

[0048] As Figure 10 shown, the energy-saving condensate water tank 16 has water inlet at the upper end and water outlet at the lower end, and exchanges heat countercurrently with the upward flowing flue gas; the outlet water enters the lower header 6 to preheat the boiler feed water; a spiral plate structure is arranged in the energy-saving condensate water tank 16 to ensure the countercurrent heat transfer enhancement effect between the water tank and the smoke pipe; as Figure 11 shown, the energy-saving condensate water sleeve 161 is provided with a water inlet chamber and a water outlet chamber at the upper and lower ends respectively. Partition plates are arranged inside the water inlet chamber and the water outlet chamber of the energy-saving condensate water sleeve 161 to force the water circulation. The energy-saving condensate water sleeve 81 is sleeved outside the smoke pipe 7 for condensation heat transfer, and is arranged as a whole by splicing two half-circles on the left and right.

[0049] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. 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 generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element, characterized in that: The invention comprises an upper header (2), a lower header (6), a smoke baffle (7), an upper water chamber (8), a lower water chamber (9), a smoke exhaust pipe (12), and two inner and outer annular pipe rows. The inner pipe row and the outer pipe row are both formed by arranging vertical water pipes (3) in a circle. The inner vertical water pipe (3) has an inner embedded smoke pipe (41). The inlet and outlet of the inner embedded smoke pipe (41) are arranged outside the vertical water pipe (3). The upper middle part of the inner vertical water pipe (3) is a membrane water-cooled wall. The lower part of the inner vertical water pipe (3) leaves a smoke gap channel. The smoke baffle (7) is welded to the lower part of the outer side of the inner pipe row. An outer circle embedded smoke pipe (42) is arranged in the outer circle vertical water pipe (3), and the outer circle vertical water pipe (3) is closely arranged in a circle. The inlet and outlet of the outer circle embedded smoke pipe (42) are respectively located on both sides of the outer circle vertical water pipe (3), and the inlet is opposite to the outlet of the inner circle embedded smoke pipe (41), and the outlet is connected to the smoke exhaust pipe (12); the two ends of the inner circle vertical water pipe (3) are respectively connected to the upper header (2) and the lower header (6); the two ends of the outer circle vertical water pipe (3) are respectively connected to the upper water chamber (8) and the lower water chamber (9), and the embedded smoke pipe (4) is a steel-aluminum composite inner finned tube enhanced heat exchange structure.

2. The gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element according to claim 1, characterized in that: Partitions are arranged in the upper water chamber (8) and the lower water chamber (9) to guide boiler feed water to flow back and forth between the upper water chamber (8) and the lower water chamber (9); the upper water chamber (8) and the lower water chamber (9) are respectively composed of two independent half circles spliced ​​together.

3. The gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element according to claim 1, characterized in that: A burner (1) is arranged on the top, and the upper header (2) and the upper water chamber (8) are both annular; the upper header (2) is arranged on the inner side of the upper water chamber (8); a central symmetrical design is adopted, the burner (1) is a diffusion burner or a metal fiber surface burner, and the burner (1) is arranged on the inner side of the upper header (2); the upper header (2) adopts an upper and lower U-shaped header (201), and the upper and lower U-shaped headers (201) adopt U-shaped lower angle rings with different lengths at both ends to weld two circumferential welds; or a U-shaped welded angle steel header (202) in which a U-shaped lower angle ring is welded to an angle steel; or a plate edge rectangular header (203) in which a plate edge rectangular is welded; or a lower U-shaped upper triangular header (20 4); the lower header (6) adopts the same structural form as the upper header (2); the upper header (2) adopts an upper and lower U-shaped header (201), wherein the upper and lower U-shaped headers (201) adopt U-shaped lower angle rings of different lengths at both ends, and two circumferential welds are welded; or a U-shaped welded angle steel header (202) in which a U-shaped lower angle ring is welded to an angle steel; or a plate edge rectangular header (203) in which a plate edge rectangular is welded; or a lower U-shaped upper triangular header (204) is adopted; the lower header (6) adopts the same structural form as the upper header (2).

4. The gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element according to claim 1, characterized in that: In the inner tube row, flat steels (5) are welded at the upper parts between adjacent vertical water tubes (3) to form a membrane water-cooled wall, and the flat steels (5) extend to the upper end of the flue gas gap channel; the width of the flat steels (5) does not exceed 6 mm, and the length of the flat steels (5) is one quarter shorter than the length of the vertical water tubes (3).

5. The gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element according to claim 1, characterized in that: The pipe end of the inner ring embedded smoke pipe (41) is only connected to the outer intersection line of the vertical water pipe (3) by fillet welding.

6. The gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element according to claim 1, characterized in that: The inner part of the embedded smoke tube (4) is a steel-aluminum composite inner wing tube, the steel-aluminum composite inner wing tube and the embedded smoke tube (4) are interference fit, the inner wing of the steel-aluminum composite inner wing tube is an axisymmetric wing, a radial wing or a centrally symmetrical wing, or the inner wing of the steel-aluminum composite inner wing tube adopts an extruded aluminum inner wing wing type (401); a part of the extruded aluminum inner wing wing type (401) is rotated to a set angle, or a fin of a set length is removed from the middle of the steel-aluminum composite inner wing tube; Or the internally embedded smoke pipe (4) is in the form of a combination of an internally threaded pipe and a steel-aluminum composite inner finned pipe, wherein the upper portion is an internally threaded pipe and the lower portion is a steel-aluminum composite inner finned pipe.

7. A gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element, characterized in that: The invention comprises an upper header (2), a lower header (6), a smoke baffle (7), an upper water chamber (8), a lower water chamber (9), a smoke exhaust pipe (12) and two inner and outer annular pipe rows, wherein the inner pipe row is formed by arranging vertical water pipes (3) in a circle, wherein the inner vertical water pipes (3) have inner embedded smoke pipes (41), the middle and upper parts of the inner vertical water pipes (3) are membrane water-cooled walls, and the lower parts of the inner vertical water pipes (3) are reserved for smoke gap channels; the embedded smoke pipes (4) are steel-aluminum composite inner fins. The invention discloses a heat exchange enhancement structure of a pipe, wherein the outer side of the vertical water pipe (3) is coupled with fins to enhance heat exchange, the outer ring pipe row adopts a smoke pipe (15) arranged in a circumferential direction to replace the vertical water pipe (3), an energy-saving condensing water tank (16) is arranged on the outer side of the smoke pipe (15), and the smoke pipe (15) is coupled with fins; the outlet of the inner ring embedded smoke pipe (41) and the inlet of the smoke pipe (15) are welded at the bottom end, the outlet of the smoke pipe (15) is connected to the exhaust pipe (12), and the inner ring pipe row and the outer ring pipe row are separated by a steel plate (13).

8. The gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element according to claim 7, characterized in that: The lower end opening of the smoke pipe (15) is connected to a drainage pipe (17), and the drainage pipe (17) is connected to a condensate collection chamber (18). The condensate collection chamber (18) is arranged at the bottom of the vertical gas-fired steam generator. Water enters the upper end of the energy-saving condensate tank (16) and discharges water at the lower end, and performs countercurrent heat exchange with the ascending flue gas. The outlet water enters the lower header (6) to preheat boiler feed water. A spiral plate structure is arranged in the energy-saving condensate tank (16), and water flows downward in a spiral manner.

9. The gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element according to claim 7, characterized in that: The energy-saving condensing water tank (16) is replaced by an energy-saving condensing water jacket (161), the two ends of which are respectively connected to an upper water chamber and a lower water chamber, a partition is provided in the upper water chamber and the lower water chamber to force water circulation, and the energy-saving condensing water jacket is placed outside the smoke pipe (15) for condensation and heat exchange; the energy-saving condensing water tank (16) and the energy-saving condensing water jacket (161) are arranged as an integral whole by splicing two half circles.

10. The gas steam generator with a vertical water pipe embedded with a smoke pipe enhanced heat transfer element according to claim 7, characterized in that: The lower part of the steel plate (13) is made of Cr25Ni20Si2 alloy material, and the upper part is made of 12Cr1MoV alloy material; refractory wool (14) is laid between the energy-saving condensing water tank (16) and the steel plate (13); and refractory material is laid between the upper and lower headers and the inner ring pipe row.

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