Premixing and membrane wall cooling burner having built-in vertical water tube, and gas fired boiler

Abstract

Disclosed in the present invention are a premixing and membrane wall cooling burner having a built-in vertical water tube, and a gas fired boiler. The gas fired boiler comprises a burner, a combustion chamber, a heat exchanger, and a flue. The burner uses a combustion mode of a built-in premixer and membrane wall cooling; a central side-by-side tube bundle or an arc-side tube bundle is used as the head of the burner; the combustion chamber is two semi-cylindrical spaces defined by the burner and the heat exchanger; and the heat exchanger is a water tube bundle connected to upper and lower annular headers and expanded along 1-3 circles of circular arcs in the radial direction. The burner and the heat exchanger can be exchanged. After a premixed gas is burned in the burner, generated flue gas scours opposite heat exchange areas and is collected and discharged by the flue. According to the present invention, the structure is compact, the resistance is low, and the heat exchange efficiency is high; the gas flow is short, mixing and distribution are uniform, deflagration is prevented, the safety is high, and the present invention is suitable for blending combustion of natural gas and low / zero carbon fuel and combustion of pure fuel; the combustion temperature is low, the load is uniform, the turndown ratio is large, and the NOx emission is low; and the burner and the heat exchanger are communicated with the headers by using integrally or partially detachable flanges, so that the maintainability is high.

Description

A vertical water tube built-in premixed membrane wall-cooled burner and gas boiler Technical Field

[0001] The present invention belongs to the field of high-efficiency, energy-saving and environmentally friendly compact burner, heat exchanger and boiler design, and specifically relates to a vertical water tube built-in premixed membrane wall-cooled burner and a gas boiler. Background Art

[0002] As environmental standards become increasingly stringent, low-nitrogen combustion and efficient heat exchange have become key technologies in gas-fired boiler development. At the same time, compact gas-fired boilers are a popular choice. Vertical gas-fired boilers are widely used in industrial applications due to their small footprint, low steel consumption, rapid steam production, and high degree of automation.

[0003] However, many vertical gas boilers currently have high nitrogen oxide emissions, and low-nitrogen combustion conversion is difficult. Premixed water-cooled combustion is a new combustion method. After the gas and the air required for combustion are completely mixed, they are sprayed out from the gaps in the water-cooled tube bundle for combustion. The setting of the water-cooled tube bundle cools the root of the flame, and the nitrogen oxide emissions of the boiler are significantly reduced. Water-cooled combustion has become a key technology for solving nitrogen oxide emissions from industrial gas boilers. The current premixed water-cooled burner head is usually composed of a cylindrical water-cooled tube bundle or a single-plane water-cooled tube bundle. The flame area is small, the burner heat load is small, the boiler power is low, and the adjustment ratio during operation is low. In addition, traditional water-cooled low-nitrogen burners are prone to carbon deposits at low loads, and long-term operation can easily lead to the scrapping of the tube bundle.

[0004] Anhui Borite Company, in patent CN 212841492.U, discloses a cylindrical, low-nitrogen, energy-saving, pressurized water-tube boiler structure. This structure utilizes a single-plane water-cooled tube bundle as the burner, with membrane-type water-cooled tubes forming a trapezoidal furnace. The burner distribution head is designed as a removable drawer, achieving low-nitrogen combustion while facilitating burner removal and cleaning. However, this structure suffers from low burner heat load and a low turndown ratio. Zhejiang Liju Company, in patents CN 110425531.A, CN 107990552.A, and CN 108036509.A, discloses three premixed water-cooled gas boiler structures using multiple combustion surfaces, multiple premixers, or multiple distributors. These structures address the low burner heat load and low turndown ratio issues of vertical premixed water-cooled gas boilers. However, these boilers require a large floor space, lack structural compactness, and are complex, costly, and difficult to maintain.

[0005] Furthermore, the current premixer, located at the front end of the burner to mix gas and air before evenly distributing the premixed gas, results in a long gas flow path, uneven mixing of gas and air, high flow resistance, and poor flow field uniformity. This makes deflagration a common occurrence during boiler ignition and combustion, impacting safe operation. Furthermore, the current water-cooled tube bundle in the burner head often consists of two staggered circles of bare tubes. The flame ejected from the gaps in the water-cooled tube bundle lacks rigidity, resulting in poor flame stability and difficulty forming a stable flame surface, making ignition and stable low-load operation difficult.

[0006] Summary of the Invention

[0007] In order to solve the above-mentioned problems existing in vertical gas-fired boilers, the present invention improves the traditional burner, embeds the gas nozzle behind the burner, combines the gas premixing process and the flow equalization process in the burner into one, and proposes a new type of built-in premixed water-cooled burner. The structure of the vertical gas-fired boiler is improved, and a premixed water-cooled combustion method is adopted. An axially symmetrical or centrally symmetrical detachable double-plane premixed water-cooled burner is set in the middle of the cylindrical furnace, or the semi-cylindrical furnace heating surface tube bundle on one side or both sides is directly used as part of the water-cooled burner, thereby increasing the heat load and adjustment ratio of the burner. The boiler has low nitrogen oxide emissions, high heat exchange efficiency, compact structure and good maintainability.

[0008] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a vertical water tube built-in premixed membrane wall-cooled burner, including a first distribution chamber, a second distribution chamber and a water-cooled tube bundle, the first distribution chamber is provided with an air inlet, a gas distribution pipe is provided in the first distribution chamber, and the gas distribution pipe has a gas inlet; the first distribution chamber is connected to the second distribution chamber; the second distribution chamber includes a partition and a distribution orifice plate, one end of the partition is connected to the first distribution chamber, and the other end is connected to the distribution orifice plate; the vertical area surrounded by the partition and the distribution orifice plate is the second distribution chamber, the distribution orifice plate is opposite to the water-cooled tube bundle, the water-cooled tube bundle is a membrane wall tube bundle, the membrane wall tube bundle is provided with air flow holes, and the membrane wall surface is a flat surface, an arc surface or a curved surface.

[0009] Furthermore, a first flow balancing orifice plate and a plurality of spoiler columns are provided in the first distribution chamber, a second flow balancing orifice plate is provided between the first distribution chamber and the second distribution chamber, the gas distribution pipe is provided between the first flow balancing orifice plate and the second flow balancing orifice plate, the spoiler columns are provided in front of and behind the first flow balancing orifice plate, the spoiler columns are arranged along the length direction of the gas distribution pipe, the two ends of the spoiler columns are connected to the first distribution chamber, the cross-section of the spoiler columns is triangular, V-shaped, square or circular, and in the case of the V-shaped cross-section, the bending angle of the V is facing the direction of the incoming air, and 3-50 spoiler columns are provided.

[0010] Furthermore, the gas distribution pipe includes a first gas distribution pipe, a second gas distribution pipe, a first gas nozzle hole, a second gas nozzle hole and a spoiler; a gas inlet is provided at one or both ends of the first gas distribution pipe, the first gas distribution pipe is connected to the second gas distribution pipe, the first gas nozzle holes are evenly provided on the gas outlet surface of the first gas distribution pipe, and the second gas nozzle holes are evenly provided on the side surface of the second gas distribution pipe; the first gas nozzle holes are arranged in 1 to 8 rows, and the second gas nozzle holes are arranged in 1 to 4 rows, the first gas nozzle holes are arranged in sequence or staggered rows, and the second gas nozzle holes are arranged in sequence or staggered rows; spoilers are welded to the top and bottom of the interface between the first gas distribution pipe and the second gas distribution pipe.

[0011] Furthermore, the flow area in the first gas distribution pipe along the gas inlet direction remains unchanged or gradually decreases, and the flow area in the second distribution chamber along the mixed gas flow direction remains unchanged or gradually decreases.

[0012] Furthermore, the first gas distribution pipe is horizontally placed above the first distribution chamber, and one end of 3 to 20 evenly arranged second gas distribution pipes is vertically connected to the first gas distribution pipe, and the other end extends into the interior of the first distribution chamber; the gas inlet is located at one end, both ends and / or the middle of the first gas distribution pipe, and 1 to 3 gas inlets are provided, and the second gas distribution pipe is provided with evenly arranged second gas nozzle holes along the direction of air flow, away from the direction of air flow, or in both directions.

[0013] Furthermore, the mixture of gas and air in the burner is fed into the burner perpendicularly or parallel to the distribution orifice plate, and the distribution orifice plate is provided with 1 to 3 layers; a third equalizing flow orifice plate is provided at the tail of the first distribution chamber, and a turning guide plate is provided when the air is fed into the burner parallel to the distribution orifice plate, and the turning guide plate is located at the junction of the first distribution chamber and the second distribution chamber, and the turning guide plate is connected to the third equalizing flow orifice plate; the two sides of the turning guide plate are connected to the two sides of the first distribution chamber and the second distribution chamber, and the cross-section is a right-angled "U" shape, a smoothly transitioned "U" shape, a "V" shape, an "L" shape or an "I" shape; when the turning guide plate is in the "I" shape, the turning guide plate is fixedly connected or hinged to the third equalizing flow orifice plate.

[0014] Furthermore, when the mixed gas enters parallel to the distribution orifice plate, 1 to 10 vertical baffles parallel to the flow direction of the mixed gas are evenly arranged in the second distribution chamber along a direction perpendicular to the flow direction of the mixed gas, the front edge of the vertical baffle is connected to the top of the second distribution chamber, the rear edge of the vertical baffle is connected to the distribution orifice plate or is spaced 5 to 20 mm from the distribution orifice plate, and the top and bottom ends of the vertical baffle are connected to the top and bottom surfaces of the second distribution chamber respectively.

[0015] Furthermore, the membrane wall tube bundle includes a plurality of light tubes, and adjacent two light tubes are welded by flat steel. The length direction of the flat steel is parallel to the light tube row, and the flat steel is located on the center line of the light tube row or deviates from the center line of the light tube row. The flat steel is correspondingly welded on both sides or on one side with the light tube; the thickness of the flat steel is 3 to 20 mm, and the welding depth of the arc surface of the flat steel in contact with the light tube in the thickness direction is at least 3 mm. The flat steel is provided with regular premixed gas spray holes from bottom to top, i.e., gas flow holes, and the premixed gas spray holes are arranged on the flat steel. The center line of the hole is perpendicular or inclined to the flat steel plane, the premixed gas spray holes are in a single row, double rows or three rows, and when there are more than one row of premixed gas spray holes, the two adjacent rows of premixed gas spray holes are arranged in sequence or staggered. The premixed gas spray holes are circular, oblong, triangular or rectangular; the long axis of the oblong premixed gas spray hole is parallel or perpendicular to the longitudinal center line of the pipe; the top angle of the triangular premixed gas spray hole is a 360° rotation angle, and can be placed upright, inverted or tilted; the long side of the rectangular premixed gas spray hole is parallel or perpendicular to the longitudinal center line of the pipe.

[0016] Furthermore, the water-cooled tube bundle includes at least two rows of light tubes, flat steel is welded to the first row of light tubes, the flat steel is located between the second row of light tubes, and a narrow gap is formed between the flat steel and the second row of light tubes, and evenly distributed flat steel fins or pads are welded on the flat steel; the flat steel fins are arc-shaped or rectangular, and the pad cross-section is square, circular or oblong. The pad is welded to the second row of light tubes, and evenly distributed air flow holes are formed between the light tubes, the pads and the flat steel; an adjustable spray hole baffle is provided on the flat steel to block the premixed gas spray holes or the air flow holes formed by the pads, and a premixed gas spray hole with the same size and position as the air flow hole is provided on the adjustable spray hole baffle, and the adjustable spray hole baffle slides axially along the membrane wall tube, and the sliding range can cover the premixed gas spray holes.

[0017] Furthermore, the membrane wall tube bundle includes multiple smooth tubes, and channel steel, I-beam, curved steel, angle steel, small round tube or semi-circular tube are welded between the smooth tubes. When the curved steel is welded between the smooth tubes, the curvature α of the curved steel is: 0<α<π; when the angle steel is welded between the smooth tubes, the angle β of the angle steel is: 0<β<180°.

[0018] Furthermore, the membrane wall tube bundle is a combination of finned tubes and smooth tubes, the finned tubes are bent at opposite sides, the smooth tubes face toward the furnace or face away from the furnace, and the finned tubes are spiral finned tubes, circular finned tubes, square finned tubes or H-shaped finned tubes.

[0019] At the same time, the present invention provides a vertical water tube built-in premixed membrane wall-cooled combustion gas boiler, including a burner, a heat exchanger, a flue, an economizer, a condenser and a chimney; the burner and the heat exchanger form two axisymmetric semi-cylindrical furnaces, and two heating surfaces, a plane heat exchange section and an arc heat exchange section, are arranged in the furnace; the burner is arranged on the chord side of the semi-cylindrical furnace, and the heat exchanger is arranged on the arc side of the semi-cylindrical furnace, or the burner is arranged on the arc side of the semi-cylindrical furnace, and the heat exchanger is arranged on the chord side of the semi-cylindrical furnace, or the burner and the heat exchanger are respectively arranged on the arc sides of two semi-cylindrical furnaces; the burner adopts A premixed water-cooled burner uses a tube bundle of a flat heat exchange section or an arc-shaped heat exchange section as the water-cooled tube bundle of the burner; when the burner is located on the chord side of the semi-cylindrical furnace, the flue gases of the two semi-cylindrical furnaces flow to the outside of the cylinder respectively; when the burner is located on the arc side of the semi-cylindrical furnace, the two semi-cylindrical furnaces are connected, and the flue gases flow into the cylinder or flow in from one side of the cylinder and out from the other side; the burner, heat exchanger, flue, economizer, condenser and chimney are connected along the direction of the flue gas flow; the burner adopts the vertical water tube built-in premixed membrane wall-cooled burner described in any one of claims 1-12.

[0020] Furthermore, the planar heat exchange section includes a tubular upper header, a side-by-side heat exchange tube bundle and a tubular lower header; the two ends of the side-by-side heat exchange tube bundle are respectively connected to the tubular upper header and the tubular lower header; the arcuate heat exchange section includes an annular upper header, an inner ring heat exchange tube bundle, an outer ring heat exchange tube bundle and an annular lower header, the outer ring heat exchange tube bundle and the inner ring heat exchange tube bundle are arranged along the semi-cylindrical surface, and the two ends of the outer ring heat exchange tube bundle and the inner ring heat exchange tube bundle are connected to the annular upper header and the annular lower header; the outer ring heat exchange tube bundle and the inner ring heat exchange tube bundle are staggered; the bottom end of the annular upper header and the top end of the annular lower header are respectively sealed and connected to the furnace upper bottom plate and the furnace lower bottom plate; outer shell baffles are arranged on the outside of the two semi-cylindrical furnaces.

[0021] Furthermore, when the maximum distance between the tubular upper header and the tubular lower header is less than the distance between the bottom of the annular upper header and the top of the annular lower header, the burner is detachable as a whole, and the tubular upper header and the tubular lower header are respectively provided with a tubular header steam outlet and a tubular header water inlet at both ends of the axial direction. The tubular header steam outlet and the tubular header water inlet are connected to the connecting pipe through a flange. The connecting pipe is a 180° elbow, one end of which is tightly connected to the flange on the tubular upper header or the tubular lower header, and the other end is connected to the outer side of the annular upper header or the annular lower header; between the tubular upper header and the tubular lower header When the maximum distance is greater than the distance between the bottom of the annular upper header and the top of the annular lower header, the burner is partially detachable, and the remaining burner parts except the tubular upper header, the side-by-side heat exchange tube bundle and the tubular lower header can be pulled out in the horizontal direction; the axial ends of the tubular upper header and the tubular lower header are respectively connected to the annular upper header and the annular lower header, and the connection parts are the inner side surface or top of the annular upper header and the inner side surface or bottom of the annular lower header; the detachable part of the burner is connected and sealed with the annular upper header, the annular lower header, the furnace upper bottom plate, the furnace lower bottom plate and the outer shell baffle by using a drawer structure.

[0022] Furthermore, when the burner is arranged on the chord side of the semi-cylindrical furnace, a flat heat exchange section tube bundle is used as the water-cooling tube bundle of the burner, and the flue is arranged on the outside of the curved surfaces of the two semi-cylindrical furnaces; when the burner is arranged on the curved side of the semi-cylindrical furnace, the outer ring heat exchange tube bundle and the inner ring heat exchange tube bundle arranged along the semi-cylindrical surface are used as the water-cooling tube bundle of the burner, and the flue is arranged on the side between the two semi-cylindrical furnaces or on the outside of the other curved surface of the semi-cylindrical furnace.

[0023] Furthermore, a downcomer is provided on the periphery of the heating surface of the heat exchanger, and both ends of the downcomer are connected to an annular upper header and an annular lower header to form a natural circulation steam boiler.

[0024] Furthermore, a radiation heating tube bundle is arranged in the semi-cylindrical furnace. The radiation heating tube bundle is concave inwardly and is divided into three sections: an upper inclined section, a middle vertical section and a lower inclined section. The three sections of a radiation heating tube are located in the same plane, the upper inclined section and the lower inclined section face the same direction, the top of the radiation heating tube bundle is connected to the inner side or the top of the annular upper header, and the bottom of the radiation heating tube bundle is connected to the inner side or the bottom of the annular lower header. The radiation heating tube bundle is evenly arranged in the circumferential direction, and the 2-5 radiation heating tube bundles on both sides of the burner have reduced lengths of the upper inclined section and the lower inclined section.

[0025] Furthermore, the vertical cross-sections of the annular upper header and the annular lower header are rectangular, circular or elliptical with chamfered or rounded corners on all sides. 2 to 3 circles of vertical heat exchange tube bundles are arranged between the annular upper header and the annular lower header. The inner circle heat exchange tube bundle close to the furnace is a plain tube, a spiral finned tube or a finned tube. When the inner circle heat exchange tube bundle is a spiral finned tube, the fin height is less than 10 mm, and when the inner circle heat exchange tube bundle is a finned tube, the fin height is less than 10 mm; the outer circle heat exchange tube bundle is an enhanced heat exchange tube bundle with a spiral finned tube, a finned tube or a special-shaped tube structure, and the height of the fin or fin is 30 to 100 mm; an annular header water inlet is arranged below the steam-water demarcation line or at the bottom of the side of the annular upper header, and an annular header steam outlet is arranged above the steam-water demarcation line or at the top of the side of the annular upper header; a sewage outlet is arranged on the side or bottom of the annular lower header.

[0026] Furthermore, 1 to 3 circles of tube bundles are arranged at the arc-shaped heat exchange section, and the cross-section of the tube bundles in the arc-shaped heat exchange section is arc-shaped, trapezoidal or "V"-shaped, and 1 to 2 rows of smooth tubes, spiral finned tubes, special-shaped tubes and / or slot guide plates are arranged at the side-by-side heat exchange tube bundles; a slot guide plate is arranged between two adjacent heat exchange tubes of the outer ring heat exchange tube bundle, and the slot guide plate is located on the inner side of the outer ring heat exchange tube bundle; or a slot guide plate is arranged between two adjacent heat exchange tubes of the inner ring heat exchange tube bundle, and the slot guide plate is located on the outer side of the inner ring heat exchange tube bundle; or slot guide plates are arranged in both the outer ring heat exchange tube bundle and the inner ring heat exchange tube bundle; an enhanced heat exchange channel is formed between the slot guide plate and the outer wall of the heat exchange tube.

[0027] Furthermore, the two heat exchange tubes at both ends of the inner ring heat exchange tube bundle and the outer ring heat exchange tube bundle are both configured as bare tubes, and a sealing tube is provided between the bare tube and the tube bundles at both ends of the side-by-side heat exchange tube bundles. The sealing tube is a bare tube, and the sealing tube is tangent to the tube bundles at both ends of the side-by-side heat exchange tube bundles. The two ends of the sealing tube are respectively connected to the annular upper header and the annular lower header, and a bending structure is provided at both ends of the sealing tube; a sealing plate is provided to seal the longitudinal gap between the two bare tubes at the same end of the inner ring heat exchange tube bundle and the outer ring heat exchange tube bundle, the sealing tube, and the burner at one end or both ends of the side-by-side heat exchange tube bundle when the burner is located on the arc side of the semi-cylindrical furnace.

[0028] Furthermore, the first flow balancing orifice plate, the second flow balancing orifice plate, the third flow balancing orifice plate, the distribution orifice plate, the sealing plate, the upper bottom plate of the furnace, the lower bottom plate of the furnace and the outer shell baffle are all made of high-temperature resistant and deformation-resistant materials, and the surfaces of the side-by-side heat exchange tube bundles, the inner ring heat exchange tube bundles and the radiation heating tube bundles that are in direct contact with the high-temperature flue gas are sprayed with nickel-chromium alloy; the burner is a natural gas burner, a natural gas blended low / zero carbon fuel burner or a pure low / zero carbon fuel burner, and the working medium of the heat exchanger is water or thermal oil.

[0029] Furthermore, when the burner is arranged on the chord side of the semi-cylindrical furnace, a double-sided burner or two single-sided burners are arranged with a side-by-side heat exchange tube bundle as a water-cooled tube bundle, and the burner flow area gradually decreases from the burner inlet to the burner end; when a double-sided burner is arranged, the burner takes in air on one side along the direction of the semi-cylindrical furnace chord, and exhausts air on both sides perpendicular to the air intake direction, and the burner is symmetrical along the axis perpendicular to the air intake direction; when two single-sided burners are arranged, the burner takes in air on both sides or one side along the direction of the semi-cylindrical furnace chord, and exhausts air on both sides perpendicular to the air intake direction, and the burner is centrally symmetrical or axially symmetrical.

[0030] Furthermore, when the burner is arranged on the arc side of the semi-cylindrical furnace, one or two single-sided burners are arranged with the outer ring heat exchange tube bundle and the inner ring heat exchange tube bundle as water-cooled tube bundles, the front end of the burner cross-section is square, the rear end is crescent-shaped, and the distribution orifice plate is arc-shaped; the diameter of the outer ring heat exchange tube bundle is larger than the diameter of the inner ring heat exchange tube bundle, the gap formed between adjacent tubes of the outer ring heat exchange tube bundle is 2-5mm, and the gap formed between adjacent tubes of the inner ring heat exchange tube bundle is 4-10mm; the number of columns of the outer ring heat exchange tube bundle is the same as the number of columns of the nozzles on the distribution orifice plate or the number of columns of the nozzles on the distribution orifice plate is an integer multiple of the number of columns of the outer ring heat exchange tube bundle, and the outer ring heat exchange tube bundle is directly opposite to the nozzles on the distribution orifice plate.

[0031] Furthermore, the flue includes a flue gas header, a flue gas duct and a flue gas outlet. When the burner is arranged on the chord side of the semi-cylindrical furnace, it is a double flue, and the two flue gas headers are connected via the flue gas duct. The flue gas in the two flue gas headers is collected through the flue gas duct and discharged from the flue gas outlet; when the burner is arranged on the arc side of the semi-cylindrical furnace, it is a single flue, and the flue gas in the flue gas header is directly discharged from the flue gas outlet; the flue gas outlet is connected to the economizer, condenser and chimney in sequence; the fan outlet is connected to the burner, and the narrow surface of the fan is parallel to the corresponding connection surface of the burner.

[0032] Furthermore, each combustion surface is provided with one or two ignition needles, which can be extended into the furnace from the side, top or bottom of the furnace. The ignition needles correspondingly pass through the sealing plate or the upper bottom plate of the furnace or the lower bottom plate of the furnace and extend into the furnace. The ignition needles are 10-50 mm away from the outer wall of the side-by-side heat exchange tube bundle or the outer wall of the inner ring heat exchange tube bundle.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects:

[0034] The present invention places the gas nozzle inside the rear of the burner, combines the gas premixing process and the flow equalization process in the burner into one, and proposes a new type of built-in premixed water-cooled burner. The gas flow is reduced, the mixing and distribution are uniform, and the flow resistance is low. It is suitable for the combustion of low / zero carbon fuel or pure low / zero carbon fuel, ensuring the safety of combustion. The present invention adopts a membrane wall tube bundle or a combination of fin tubes and light tubes as the burner water-cooled tube bundle to rectify the incoming premixed gas, thereby improving the flame stiffness, facilitating ignition and stable combustion, and not prone to backfire and flameout. At the same time, the flame length is short, the furnace space is small, and pollutant emissions are low.

[0035] Based on the present invention, a premixed water-cooled burner is provided, which can be arranged as a relative combustion surface, thereby increasing the flame area while reducing nitrogen oxide emissions and increasing the heat load of the burner. An axially symmetrical or centrally symmetrical double-plane premixed water-cooled burner is arranged in the middle of the cylindrical furnace, or one or two semi-cylindrical furnace heating surface tube bundles are directly used as part of the water-cooled burner, and half of the burners can be opened separately for combustion at the same time, thereby increasing the regulation ratio. The present invention adopts two semi-circular columnar spaces as the furnace, and the burner, heat exchanger, and flue are all symmetrical structures, with uniform combustion, low resistance, and strong adaptability to boilers. It can be used as a modification plan for other industrial boilers. The burner water-cooled tube bundle and the heat exchanger tube bundle are arranged to increase the heating surface, improve the heat exchange efficiency, and make the structure more compact.

[0036] Furthermore, the burner of the present invention is designed as a detachable drawer type, which is convenient for disassembly and cleaning of the burner. The space left after the burner is disassembled is convenient for repairing and cleaning the inside of the furnace, and the maintainability of the boiler is greatly improved.

[0037] Furthermore, the burner spray hole size of the present invention is adjustable, and a wide range of load adjustment can be achieved by simply moving the adjustable spray hole baffle a small distance, thereby achieving strong load adaptability.

[0038] Furthermore, the present invention adds a radiation heating tube bundle on the basis of the burner water-cooling tube bundle and the heat exchanger tube bundle in the furnace, further improving the compactness of the structure, and adopts spiral fin tubes, guide plates, narrow gaps and other methods to enhance heat exchange, with high heat exchange efficiency and low flow resistance.

[0039] Furthermore, the present invention increases the operating life and safety of the boiler by providing refractory materials and spraying nickel-chromium alloy on the surface of the tube bundle that is in direct contact with the high-temperature flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG1a is a schematic cross-sectional view of a boiler according to a first embodiment of the present invention.

[0041] FIG1b is a schematic cross-sectional view of the boiler according to the second embodiment of the present invention.

[0042] FIG1c is a schematic cross-sectional view of the boiler of Scheme 3 of the present invention.

[0043] FIG1d is a schematic cross-sectional view of the boiler according to the fourth embodiment of the present invention.

[0044] FIG1e is a schematic cross-sectional view of the boiler according to the fifth embodiment of the present invention.

[0045] FIG2 a is a schematic front cross-sectional view of a boiler according to a first embodiment of the present invention.

[0046] FIG2 b is a schematic diagram of a right sectional view of a boiler according to the second embodiment of the present invention.

[0047] FIG2c is a schematic front cross-sectional view of the boiler according to the third embodiment of the present invention.

[0048] FIG2 d is a schematic diagram of a right sectional view of a boiler according to a fourth embodiment of the present invention.

[0049] FIG2e is a schematic diagram of a right sectional view of a boiler according to a fifth embodiment of the present invention.

[0050] FIG3 a is a schematic front cross-sectional view of a burner according to the second embodiment of the present invention.

[0051] FIG3 b is a schematic cross-sectional view of the burner of Scheme 2 of the present invention.

[0052] FIG3 c is a schematic top cross-sectional view of a burner according to a first embodiment of the present invention.

[0053] FIG3 d is a schematic cross-sectional view of the burner type 2 of solution 1 of the present invention.

[0054] FIG4 a is a schematic diagram of the axial cross-section of the burner of Scheme 3 and Scheme 4 of the present invention.

[0055] FIG4 b is a front cross-sectional schematic diagram of the burner of Scheme 3 and Scheme 4 of the present invention.

[0056] FIG4c is a schematic cross-sectional view of the burner of Scheme 3 and Scheme 4 of the present invention.

[0057] FIG5a is a schematic cross-sectional view of a burner according to a fifth embodiment of the present invention.

[0058] FIG5 b is a schematic left sectional view of the burner of Scheme 5 of the present invention.

[0059] FIG5c is a schematic front cross-sectional view of the burner of Scheme 5 of the present invention.

[0060] FIG6 a is a schematic diagram of a partial left sectional view of the bend of the burner of Scheme 5 of the present invention.

[0061] FIG6 b is a schematic diagram of a partial left sectional view of a distribution chamber of a burner type 1 according to solution 5 of the present invention.

[0062] FIG6c is a partial front cross-sectional schematic diagram of a distribution chamber of a burner type 1 according to solution 5 of the present invention.

[0063] FIG6 d is a partial cross-sectional schematic diagram of the distribution chamber of the burner type 2 of the fifth embodiment of the present invention.

[0064] FIG6e is a schematic diagram of a partial upper cross-section of the distribution chamber of the burner type 2 of the fifth embodiment of the present invention.

[0065] FIG7 a is a schematic diagram of a circular hole tube array of a membrane wall water-cooled burner head according to the present invention.

[0066] FIG7 b is a schematic diagram of a tube row with oblong holes in a membrane wall water-cooled burner head according to the present invention.

[0067] FIG8 a is a schematic diagram showing the welding of the flat steel of the membrane wall water-cooled burner head and both sides of the light tube according to the present invention.

[0068] FIG8 b is a schematic diagram of single-side welding of the flat steel and the light tube of the membrane wall water-cooled burner head of the present invention.

[0069] FIG9 a is a schematic diagram of the arrangement of the spiral finned tube and the smooth tube combination of the water-cooled burner head of the present invention.

[0070] FIG9 b is a schematic diagram of the combined arrangement of the “H”-shaped finned tubes and the smooth tubes of the water-cooled burner head of the present invention.

[0071] FIG9c is a schematic diagram of the arrangement of the straight “H”-shaped finned tubes and the light tubes in the water-cooled burner head of the present invention.

[0072] FIG10 a is a schematic diagram showing the arrangement of the water-cooled burner head flat steel and two rows of light tubes in combination according to the present invention.

[0073] FIG10 b is a schematic diagram showing the arrangement of the water-cooled burner head flat steel through the spacer block and light tube combination of the present invention.

[0074] FIG10c is a schematic diagram showing the arrangement of the water-cooled burner head flat steel in combination with two rows of light tubes through arc-shaped plate fins according to the present invention.

[0075] FIG10 d is a schematic diagram showing the arrangement of the water-cooled burner head flat steel in combination with two rows of light tubes through rectangular plate fins according to the present invention.

[0076] FIG10e is a schematic diagram showing the arrangement of the flat steel of the water-cooled burner head of the present invention in combination with two rows of light tubes through pin fins.

[0077] FIG11 a is an axial schematic diagram of a method for adjusting the size of the premixed gas nozzle of a water-cooled burner head according to the present invention.

[0078] FIG11 b is a front view schematic diagram of a method for adjusting the size of the premixed gas nozzle of the water-cooled burner head of the present invention.

[0079] FIG. 11 c is a front view schematic diagram of a method for adjusting the nozzle size of a water-cooled combustion head gasket of the present invention.

[0080] FIG12a is a schematic diagram showing the arrangement of the channel steel and light tube of the membrane wall water-cooled combustion head of the present invention.

[0081] FIG12 b is a schematic diagram of the arrangement of the I-beam and light tube of the membrane wall water-cooled burner head of the present invention.

[0082] FIG12c is a schematic diagram showing the arrangement of the arc steel and light tube of the membrane wall water-cooled burner head of the present invention.

[0083] FIG12d is a schematic diagram showing the arrangement of the angle steel and light tube of the membrane wall water-cooled combustion head of the present invention.

[0084] FIG12e is a schematic diagram showing the arrangement of the small circular tubes and light tubes of the membrane wall water-cooled burner head of the present invention.

[0085] FIG12f is a schematic diagram showing the arrangement of the semicircular tubes and light tubes of the membrane wall water-cooled burner head of the present invention.

[0086] FIG13 is a front view schematic diagram of the overall structure of the boiler of the present invention.

[0087] FIG14 a is a schematic diagram of a fan arrangement according to the present invention.

[0088] FIG14 b is a schematic diagram of a second fan arrangement according to the present invention.

[0089] FIG14c is a third schematic diagram of the fan arrangement of the present invention.

[0090] Wherein: 1: burner, 11: burner inlet, 111: gas inlet, 112: air inlet, 12: first distribution chamber, 121: gas distribution pipe, 1211: first gas distribution pipe, 1212: second gas distribution pipe, 1213: first gas nozzle, 1214: second gas nozzle, 1215: spoiler, 122: first flow balancing orifice plate, 123: second flow balancing orifice plate, 124: third flow balancing orifice plate, 125: spoiler column, 126: turning guide plate, 13: second distribution chamber, 131: partition, 132: distribution orifice plate, 14: flat heat exchange section, 141: tubular upper header, 142: parallel heat exchange tube bundle, 1421: first row of light tubes, 1422: second row of light tubes, 143: tubular lower header, 144: tubular header water inlet, 145: tubular header outlet Steam port, 15: ignition needle, 16: flat steel, 161: premixed gas nozzle, 162: pad, 163: flat steel fin, 17: weld, 18: adjustable nozzle baffle, 2: heat exchanger, 21: arc-shaped heat exchange section, 211: annular upper header, 212: inner ring heat exchange tube bundle, 213: outer ring heat exchange tube bundle, 214: downcomer, 215: annular lower header, 216: annular header water inlet, 2 17: Steam outlet of annular header, 218: Sewage outlet, 22: Sealing plate, 23: Slit guide plate, 24: Upper bottom plate of furnace, 25: Lower bottom plate of furnace, 26: Shell baffle, 27: Radiation heating tube bundle, 28: Sealing pipe, 29: Connecting pipe, 3: Flue, 31: Flue gas header, 32: Flue gas duct, 33: Flue outlet, 4: Economizer, 5: Condenser, 6: Chimney, 7: Fan.

[0091] DETAILED DESCRIPTION

[0092] The present invention is described in further detail below with reference to the accompanying drawings:

[0093] 3 , 4 and 5 , a vertical water-tube built-in premixed membrane wall-cooled burner provided by the present invention includes a first distribution chamber 12, a second distribution chamber 13 and a water-cooled tube bundle, the first distribution chamber 12 is provided with an air inlet, a gas distribution pipe 121 is provided in the first distribution chamber 12, and the gas distribution pipe 121 has a gas inlet 111; the first distribution chamber 12 is connected to the second distribution chamber 13; the second distribution chamber 13 includes a partition 131 and a distribution orifice plate 132, one end of the partition 131 is connected to the first distribution chamber 12, and the other end is connected to the distribution orifice plate 132; the vertical area surrounded by the partition 131 and the distribution orifice plate 132 is the second distribution chamber 13, and the distribution orifice plate 132 is opposite to the water-cooled tube bundle, the water-cooled tube bundle is a membrane wall tube bundle, and air flow holes are provided on the membrane wall tube bundle, and the membrane wall surface is a plane, an arc surface or a curved surface.

[0094] 1 and 2 , the present invention provides a vertical water-tube built-in premixed membrane-type wall-cooled combustion gas boiler, comprising a burner 1, a heat exchanger 2, a flue 3, an economizer 4, a condenser 5, a chimney 6, and supporting boiler accessories such as a fan 7, a water pump, a gas valve group, and a controller; the burner 1 comprises a burner inlet 11, a first distribution chamber 12, a first flow-averaging orifice plate 122, a second distribution chamber 13, a distribution orifice plate 132, a planar heat exchange section 14, a tubular upper header 141, a side-by-side heat exchange tube bundle 142, a tubular lower header 143, a tubular header water inlet 144, a tubular header steam outlet 145, and an ignition needle 15;

[0095] The heat exchanger 2 includes an arc-shaped heat exchange section 21, an annular upper header 211, an inner ring heat exchange tube bundle 212, an outer ring heat exchange tube bundle 213, a downcomer 214, an annular lower header 215, an annular header water inlet 216, an annular header steam outlet 217, a sewage outlet 218, a sealing plate 22, a slit guide plate 23, a furnace upper bottom plate 24, a furnace lower bottom plate 25, an outer shell baffle 26, a radiation heating tube bundle 27, a sealing pipe 28 and a connecting pipe 29; the flue 3 includes a flue gas header 31, a flue gas duct 32 and a flue outlet 33; the burner 1, the heat exchanger 2, the flue 3, the economizer 4, the condenser 5 and the chimney 6 are connected in sequence, and the top of the outer shell baffle 26 is connected to the annular upper header 211 The bottom of the shell baffle 26 is connected to the annular lower header 215, and the side end of the shell baffle 26 is connected to the flue 3, with only the inlet portion of the burner 1 and the outlet portion of the flue 3 exposed; the burner 1, the heat exchanger 2 and the flue 3 form a cylindrical vertical boiler body; the burner 1 and the heat exchanger 2 form two axially symmetrical semi-cylindrical furnaces; the burner 1 is located on the chord side of the semi-cylindrical furnace, and the heat exchanger 2 is located on the arc side of the semi-cylindrical furnace; or the burner 1 is located on the arc side of the semi-cylindrical furnace, and the heat exchanger 2 is located on the chord side of the semi-cylindrical furnace; or the burner 1 and the heat exchanger 2 are located on the two arc sides respectively; the burner 1 adopts a premixed water-cooled combustion method, including two opposite combustion surfaces, corresponding to two heat exchange areas. The mixed gas inlet 11 of the burner 1 and the flue outlet 33 of the flue 3 are both arranged on the side of the furnace.

[0096] 1 and 2, the gas boiler includes five layout schemes. The preferred scheme 1 is that the burner 1 is located on one side of the semi-cylindrical furnace chord, the heat exchanger 2 is located on one side of the two arc surfaces of the two semi-cylindrical furnaces, the burner 1 takes in air on one side along the direction of the semi-cylindrical furnace chord, and exhausts air on both sides perpendicular to the air intake direction, and the burner 1 is symmetrical along the axis perpendicular to the air intake direction; the burner 1 in scheme 2 is located on both chord sides of the semi-cylindrical furnace, the heat exchanger 2 is located on both arc sides of the two semi-cylindrical furnaces, the burner 1 takes in air on both sides along the direction of the semi-cylindrical furnace chord, and exhausts air on both sides perpendicular to the air intake direction, and the burner 1 is symmetrical along the axis perpendicular to the air intake direction; the burner 1 in scheme 3 is located on both arc sides of the two semi-cylindrical furnaces, the heat exchanger 2 is located on the chord side of the semi-cylindrical furnace, the burner 1 takes in air on both sides along the direction of the semi-cylindrical furnace chord, and exhausts air on both sides perpendicular to the air intake direction, and the burner 1 is symmetrical along the axis. Air is taken in from both sides in the direction of the chord, and air is exhausted from one side in the direction of the semi-cylindrical furnace chord. The burner 1 is symmetrical about the air intake direction. The burner 1 and the heat exchanger 2 of Scheme 4 are respectively located on the two arc sides of the two semi-cylindrical furnaces. The burner 1 takes in air from one side in the direction perpendicular to the chord of the semi-cylindrical furnace, and exhausts air from one side in the other side perpendicular to the chord of the semi-cylindrical furnace. The burner is symmetrical about the air intake direction or the air intake direction. The burner 1 and the heat exchanger 2 of Scheme 5 are respectively located on the two arc sides of the two semi-cylindrical furnaces, and the arc surface of the burner 1 is changed to a trapezoidal surface. The burner 1 takes in air from one side in the direction perpendicular to the chord of the semi-cylindrical furnace, and exhausts air from one side in the other side perpendicular to the chord of the semi-cylindrical furnace. The burner is symmetrical about the air intake direction. The flue gas of Scheme 1 and Scheme 2 is discharged from the boiler body through two flues 3 in a direction perpendicular to the semi-cylindrical furnace chord; the flue gas of Scheme 3 is discharged from the boiler body through one flue 3 or two flues 3 in a direction parallel to the semi-cylindrical furnace chord; the flue gas of Scheme 4 and Scheme 5 is discharged from the boiler body through one flue 3 in a direction perpendicular to the semi-cylindrical furnace chord; with reference to Figures 1a, 1b, and 1c, the direction in which the mixed gas enters the boiler body of Scheme 1, Scheme 2, and Scheme 3 is perpendicular to the direction in which the flue gas leaves the boiler body, the direction in which the mixed gas enters the boiler body points to the center of the furnace, and the direction in which the flue gas leaves the boiler body is away from the center of the furnace; with reference to Figures 1d and 1e, the direction in which the mixed gas enters the boiler body of Scheme 4 and Scheme 5 is parallel to the direction in which the flue gas leaves the boiler body, the direction in which the mixed gas enters the boiler body points to the center of the furnace, and the direction in which the flue gas leaves the boiler body is away from the center of the furnace; in the above schemes, when two flues 3 are required, the two flues 3 are connected by a flue gas duct 32.

[0097] Referring to Figures 1a, 1b, 3a, 3b, 3c and 3d, the burner 1 of Scheme 1 and Scheme 2 includes a burner inlet 11, a first distribution chamber 12, a first flow balancing orifice plate 122, a second distribution chamber 13, a distribution orifice plate 132, a tubular upper header 141, a side-by-side heat exchange tube bundle 142, a tubular lower header 143, a tubular header water inlet 144, a tubular header steam outlet 145 and an ignition needle 15. The burner inlet 11 is a cylinder with a circular or square cross-section. Both ends of the cylinder are open, and a flange is provided at one end. The flange side of the burner inlet 11 is tightly connected to the fan 7. The other end of the burner inlet 11 is connected to the first distribution chamber 12. The first distribution chamber 12 is surrounded by a cylinder in the form of a circular-to-rectangular or square-to-rectangular cylinder and a rectangular cylinder. The height of the first distribution chamber 12 is equal to the distance between the bottom of the annular upper header 211 and the top of the annular lower header 215. A first equalizing orifice plate 122 is welded to the rectangular cylinder side of the first distribution chamber 12. The first equalizing orifice plate 122 is rectangular and has circular, square, or triangular nozzle holes evenly distributed on the first equalizing orifice plate 122. The rear end of the first equalizing orifice plate 122 is welded to the second distribution chamber 13. The second distribution chamber 13 is approximately a prismatic space. The cross-section of the second distribution chamber 13 is scissor-shaped, right-angled trapezoidal, curved right-angled trapezoidal, rectangular, etc. The cross-section of the second distribution chamber 13 gradually decreases or remains unchanged along the direction of gas flow. One or two sides of the second distribution chamber 13 are distribution orifice plates 132. The distribution orifice plates 132 can be set as flat plates, folded plates or curved plates according to the top cross-section of the second distribution chamber 13. Circular, square or triangular spray holes are evenly arranged on the distribution orifice plates 132. The hydraulic diameter of the spray holes is less than 4 mm. One or two rows of evenly arranged parallel heat exchange tube bundles 142 are set opposite the distribution orifice plates 132. The number of rows of the parallel heat exchange tube bundles 142 is the same as the number of rows of spray holes on the distribution orifice plates 132 or more. The number of nozzle rows on the distribution orifice plate 132 is an integer multiple of the number of rows of parallel heat exchange tube bundles 142. The row of parallel heat exchange tube bundles 142 adjacent to the distribution orifice plate 132 is arranged directly opposite the nozzles on the distribution orifice plate 132. This means that the gas ejected from the nozzles on the distribution orifice plate 132 flows precisely along the centerline of each tube in the parallel heat exchange tube bundle 142 or evenly along its sidewalls. The distance between the tube walls of the row of parallel heat exchange tube bundles 142 adjacent to the distribution orifice plate 132 and the distribution orifice plate 132 is 5 to 30 mm. The upper and lower ends of the parallel heat exchange tube bundles 142 are connected to the tubular upper header 141 and the tubular lower header 143, respectively. Burner 1 can be a single burner or two identical burners arranged axially or centrally symmetrically. The burner 1 of the scheme 1 and the scheme 2 adopts an integral burner 1 with double-sided air outlet, refer to Figure 3c; the burner 1 can also adopt two burners 1 with single-sided air outlet arranged side by side in the same direction or opposite directions, refer to Figure 1b, Figure 3b, and Figure 3d.

[0098] 1c, 1d and 4, the burner 1 of the scheme three and scheme four includes a burner inlet 11, a first distribution chamber 12, a first flow balancing orifice plate 122, an inner ring heat exchange tube bundle 212, an outer ring heat exchange tube bundle 213, a sealing plate 22, a slit guide plate 23 and an ignition needle 15; the burner inlet 11 is a cylinder, the cylinder is an open cylindrical or square, a flange is welded at one end of the cylinder, the flange side of the burner inlet 11 is connected to the fan 7, and the other end of the burner inlet 11 is welded in sequence with a cylinder in the form of a circular to rectangular or a square to rectangular and a rectangular cylinder, and a crescent-shaped cylinder is welded at the rear end of the rectangular cylinder, the cylinder in the form of a circular to rectangular or square to rectangular is connected to a rectangular cylinder to form a first distribution chamber 12, and the crescent-shaped cylinder forms a second distribution chamber 13. A flow balancing orifice plate can be arranged between the first distribution chamber 12 and the second distribution chamber 13. An arc-shaped distribution orifice plate 132 is installed on the inner curved surface of the second distribution chamber 13. Distributor orifices are evenly distributed on this plate 132. The circular orifices have a diameter of less than 4 mm. Behind this plate 132, a uniformly arranged outer heat exchange tube bundle 213 and inner heat exchange tube bundle 212 are sequentially arranged. The diameter of the outer heat exchange tube bundle 213 is larger than that of the inner heat exchange tube bundle 212. The gaps between adjacent tubes in the outer heat exchange tube bundle 213 are 2-5 mm, while the gaps between adjacent tubes in the inner heat exchange tube bundle 212 are 4-10 mm. The outer heat exchange tube bundle 213 and the inner heat exchange tube bundle 212 are arranged in staggered rows. The number of rows in the outer heat exchange tube bundle 213 is the same as the number of rows of nozzles in the distribution orifice plate 132, or the number of rows of nozzles in the distribution orifice plate 132 is an integer multiple of the number of rows in the outer heat exchange tube bundle 213. The outer heat exchange tube bundle 213 and the nozzles in the distribution orifice plate 132 are directly aligned, meaning that the gas ejected from the nozzles in the distribution orifice plate 132 flows precisely along the centerline of each tube in the outer heat exchange tube bundle 213 or evenly along its sidewalls. The inner heat exchange tube bundle 212 and the outer heat exchange tube bundle 213 are connected to the annular upper header 211 and the annular lower header 215 at their upper and lower ends, respectively.

[0099] 1a, 1b, 2a, and 2b, the heat exchanger 2 of Scheme 1 and Scheme 2 includes a curved heat exchange section 21, a sealing plate 22, a slit guide plate 23, a furnace upper bottom plate 24, a furnace lower bottom plate 25, a shell baffle 26, a sealing pipe 28, and a connecting pipe 29. The curved heat exchange section 21 includes an annular upper header 211, an inner ring heat exchange tube bundle 212, an outer ring heat exchange tube bundle 213, a downcomer 214, an annular lower header 215, an annular header water inlet 216, an annular header steam outlet 217, and a sewage outlet 218.

[0100] 1c, 1d, 1e, 2c, 2d, and 2e, the heat exchanger 2 of the third, fourth, and fifth schemes includes a planar heat exchange section 14, an annular upper header 211, an inner heat exchange tube bundle 212, an outer heat exchange tube bundle 213, a downcomer 214, an annular lower header 215, an annular header water inlet 216, an annular header steam outlet 217, a sealing plate 22, a slit guide plate 23, a furnace upper bottom plate 24, a furnace lower bottom plate 25, a radiation heating tube bundle 27, and a sealing tube 28. The planar heat exchange section 14 includes a tubular upper header 14 1. Side-by-side heat exchange tube bundle 142, tubular lower header 143, tubular header water inlet 144, tubular header steam outlet 145; the inner ring heat exchange tube bundle 212 and the outer ring heat exchange tube bundle 213 on both arc sides of Scheme 3 are both burner water-cooled tube bundles. In Schemes 4 and 5, the inner ring heat exchange tube bundle 212 and the outer ring heat exchange tube bundle 213 on one arc side are burner water-cooled tube bundles, and the inner ring heat exchange tube bundle 212 and the outer ring heat exchange tube bundle 213 on the other arc side are heat exchange tube bundles; two parallel side-by-side heat exchange tube bundles 142 are provided, and a gap of 50-300 mm is provided between the tube banks. For scheme three, one end of the two side-by-side heat exchange tube bundles 142 is sealed by a sealing plate 22, and the other end is a flue 3; or both sides of the two side-by-side heat exchange tube bundles 142 are flues 3. For schemes four and five, both ends of the two side-by-side heat exchange tube bundles 142 are sealed by a sealing plate 22.

[0101] Referring to Figures 1a, 1b, 1c, 1d, 1e, 2a, 2b, 2c, 2d, and 2e, five schemes are shown, each with or without the arrangement of radiation-heating tube bundles 27 within the furnace. A half-circle of radiation-heating tube bundles 27 is arranged within each of the two semi-cylindrical furnace spaces. Each tube bundle 27 is concave inwardly and consists of three sections: an upper inclined section, a middle vertical section, and a lower inclined section. These three sections lie on the same plane, with the upper and lower inclined sections facing the same direction. The tops of the tube bundles 27 connect to the inside or top of the annular upper header 211, and the bottoms connect to the inside or bottom of the annular lower header 215. The tube bundles 27 are evenly distributed along the circumference, with the two to five tube bundles 27 on either side of the burner 1 having reduced upper and lower inclined sections.

[0102] The annular header water inlet 216 is located below the steam-water dividing line on the side of the annular upper header 211 or at the bottom. The annular header steam outlet 217 is located above the steam-water dividing line on the side of the annular upper header 211 or at the top. The sewage outlet 218 is located on the side or bottom of the annular lower header 215. The vertical cross-sections of the annular upper and lower headers 211 and 215 are rectangular, circular, or elliptical with chamfered corners. The annular upper header 211 is 0.4 to 0.8 meters high, and the annular lower header 215 is 0.2 to 0.4 meters high. Two or three circles of vertical heat exchange tube bundles are arranged between the annular upper header 211 and the annular lower header 215. The inner circle heat exchange tube bundle 212 is a plain tube, a spiral finned tube or a finned tube. When the inner circle heat exchange tube bundle 212 is a spiral finned tube, the fin height is less than 10 mm. When the inner circle heat exchange tube bundle 212 is a finned tube, the fin height is less than 10 mm. The outer circle heat exchange tube bundle 213 is an enhanced heat exchange tube bundle such as a spiral finned tube, a finned tube, or a special-shaped tube. The height of the fin or fin can be 30 to 100 mm. The furnace upper floor plate 24 is tightly welded to the bottom of the annular upper header 211, while the furnace lower floor plate 25 is tightly welded to the top of the annular lower header 215. The annular upper header 211 is equipped with a steam-water separator and multiple flange connections for water intake, steam exhaust, maintenance, and installation of pressure gauges, thermometers, water level gauges, and safety valves. The annular lower header 215 is also equipped with multiple flange connections for maintenance, wastewater removal, and temperature and pressure measurement. In the five schemes described above, the parallel heat exchange tube bundles 142 can be equipped with one or two additional bare tubes, spirally finned tubes, special-shaped tubes, and / or guide plates to enhance heat exchange. A slit guide plate 23 with a herringbone, V-shaped or triangular cross-section is arranged between two adjacent heat exchange tubes of the outer ring heat exchanger tube bundle 213, and the slit guide plate 23 is located on the inner side of the outer ring heat exchanger tube bundle 213, with the tip facing outward; or a slit guide plate 23 with a herringbone, V-shaped or triangular cross-section is arranged between two adjacent heat exchange tubes of the inner ring heat exchanger tube bundle 212, and the slit guide plate 23 is located on the outer side of the inner ring heat exchanger tube bundle 212, with the tip facing inward; or slit guide plates 23 are arranged in both the outer ring heat exchanger tube bundle 213 and the inner ring heat exchanger tube bundle 212. The two heat exchange tubes at both ends of the inner ring heat exchange tube bundle 212 and the outer ring heat exchange tube bundle 213 are both configured as bare tubes. Sealing tubes 28 are provided at the tangent points to the tube bundles at both ends of the parallel heat exchange tube bundle 142. The sealing tubes 28 are bare tubes, and the top and bottom of the sealing tubes 28 are bent so as to be connected to the annular upper header 211 and the annular lower header 215. A sealing plate 22 is used to seal the longitudinal gap between the two bare tubes and the sealing tube 28 at the same end of the inner ring heat exchange tube bundle 212 and the outer ring heat exchange tube bundle 213. The sealing plate 22, the outer shell baffle 26, and the sealing tube 28 surround the parallel heat exchange tube bundle 142, the inner ring heat exchange tube bundle 212, the outer ring heat exchange tube bundle 213, and the radiation heating tube bundle 27 to form a heated area. A downcomer 214 is provided in the peripheral area that is not heated or is heated less, thereby forming a natural circulation steam boiler. When the downcomer 214 is not provided, a cross-flow steam or hot water boiler is formed.The side-by-side heat exchange tube bundle 142, the inner ring heat exchange tube bundle 212, the outer ring heat exchange tube bundle 213, and the sealing tube 28 are all connected to the header using a necking process; refractory mud is provided on the outside of the tubular upper header 141, the outside of the tubular lower header 143, the bottom of the annular upper header 211, the top of the annular lower header 215, the bottom of the furnace upper bottom plate 24, the top of the furnace lower bottom plate 25, and the tube bundle necking; thermal insulation material is provided on the inside or outside of the shell baffle 26, the annular upper header 211, the annular lower header 215, the furnace upper bottom plate 24, the furnace lower bottom plate 25, and the outside of the flue 3.The flue 3 includes a flue gas header 31, a flue gas duct 32 and a flue gas outlet 33; the flue gas header 31 is a cavity with a rectangular cross-section or a cavity with a circular cross-section; referring to Figures 1a, 1b, 2a and 2b, Schemes 1 and 2 are double flues, and the two flue gas headers 31 are connected via a flue gas duct 32, and the flue gases in the two flue gas headers 31 are collected through the flue gas duct 32 and discharged from the boiler body through the flue gas outlet 33; referring to Figures 1c, 1d, 1e, 2c, 2d and 2e, Schemes 3, 4 and 5 are single flues, and the flue gases in the flue gas header 31 are directly discharged from the boiler body through the flue gas outlet 33; the flue gas outlet 33 is directly and tightly connected to the economizer 4 through a flange, or the flue gas outlet 33 is connected to the economizer 4 after turning. The flue gas inlet end of the flue gas header 31 is tightly connected with the outer shell baffle 26, the annular upper header 211 and the annular lower header 215. The flue gas inlet end of the flue gas header 31 in Scheme 1, Scheme 2, Scheme 4 and Scheme 5 is tightly connected with the outer shell baffle 26. Referring to Figures 1c and 2c, the flue gas inlet end of the flue gas header 31 in Scheme 3 passes through the outer shell baffle 26, and the outer side wall of the cavity of the flue gas inlet end is tightly connected with the outer shell baffle 26. The end of the cavity of the flue gas header 31 is tightly connected with the two water-cooling tubes on one side of the side-by-side heat exchange tube bundle 142; the maximum distance between the tubular upper header 141 and the tubular lower header 143 is less than the distance between the bottom of the annular upper header 211 and the top of the annular lower header 215; the tubular upper header 141 The tubular header steam outlet 145 and the tubular header water inlet 144 are respectively opened at both ends of the axial direction of the tubular lower header 143, and the tubular header steam outlet 145 and the tubular header water inlet 144 are connected to the connecting pipe 29 through a flange; the burner 1 is detachable as a whole; or the maximum distance between the tubular upper header 141 and the tubular lower header 143 is greater than the distance between the bottom of the annular upper header 211 and the top of the annular lower header 215, and the axial ends of the tubular upper header 141 and the tubular lower header 143 are respectively connected to the annular upper header 211 and the annular lower header 215, and the connection parts are the inner side or top of the annular upper header 211 and the inner side or bottom of the annular lower header 215; in this case, the connecting pipe 29 is not required, and the burner 1 is Partially detachable, in which the tubular upper header 141, the side-by-side heat exchange tube bundle 142 and the tubular lower header 143 cannot be pulled out, and the rest of the burner 1 can be pulled out and disassembled; or the burner 1 is non-detachable; the pull-out part of the burner 1 is connected and sealed with the annular upper header 211, the annular lower header 215, the furnace upper bottom plate 24, the furnace lower bottom plate 25 and the outer shell baffle 26 in a drawer manner, is placed in the furnace through the opening of the outer shell baffle 26, and is fixed under the constraint of the preset guide rail in the furnace; the connecting pipe 29 is a 180° elbow, one end of which is tightly connected to the flange on the tubular upper header 141 or the tubular lower header 143, and the other end is connected to the outside of the annular upper header 211 or the annular lower header 215.The first flow balancing orifice plate 122, distribution orifice plate 132, sealing plate 22, furnace upper bottom plate 24, furnace lower bottom plate 25, and shell baffle 26 are all made of high temperature resistant and deformation resistant materials; the boiler working medium can be water or organic medium such as heat transfer oil; the side-by-side heat exchange tube bundle 142, inner ring heat exchange tube bundle 212 and radiation heating tube bundle 27 and other tube bundles that are in direct contact with high temperature flue gas are sprayed with nickel-chromium alloy; the distribution orifice plate 132 in the first and second schemes are 2 and the parallel heat exchange tube bundle 142 can be correspondingly set as a flat surface, a concave curved surface, a convex curved surface or a folded plate surface; each combustion surface is arranged with one or two ignition needles 15, and the ignition needles 15 can be extended into the furnace from the side, top or bottom of the furnace, and the ignition needles 15 correspondingly pass through the sealing plate 22, the furnace upper bottom plate 24 or the furnace lower bottom plate 25 and extend into the furnace. The minimum distance between the ignition needles 15 and the outer wall of the parallel heat exchange tube bundle 142 or the outer wall of the inner ring heat exchange tube bundle 212 is 10-50 mm; the furnace upper bottom plate 24 and the furnace lower bottom plate 25 are circular plates, and the furnace upper bottom plate 24 is tightly welded to the bottom or inner side of the annular upper header 211, and the furnace lower bottom plate 25 is tightly welded to the top or inner side of the annular lower header 215; gaps are left on the surfaces of the furnace upper bottom plate 24 and the furnace lower bottom plate 25 for the side-by-side heat exchange tube bundle 142 and the radiation heating tube bundle 27 to pass through, and the gaps are sealed with refractory mud.

[0103] Referring to Figures 1e, 2e, 5a, 5b, 5c, 6a, 6b, 6c, 6d, and 6e, the burner 1 of Scheme 5 includes a burner inlet 11, a first distribution chamber 12, a second distribution chamber 13, and a water-cooled tube bundle composed of a flat heat exchange section 14 tube bundle, wherein the burner inlet 11 includes a gas inlet 111 and an air inlet 112, the first distribution chamber 12 includes a gas distribution pipe (121), a first flow balancing orifice plate 122, a second flow balancing orifice plate 123, a third flow balancing orifice plate 124, a spoiler column 125, and a turning guide plate 126, the gas distribution pipe 121 includes a first gas distribution pipe 1211 and a second gas distribution pipe 1212, the first gas distribution pipe 1211 is provided with a first gas spray hole 1213, the second gas distribution pipe 1212 is provided with a second gas spray hole 1214, and the second distribution chamber 13 includes a partition 131 and a distribution orifice plate 132. The burner 1 is a rectangular parallelepiped as a whole. An air inlet 112 is provided on the wide surface of the rectangular parallelepiped, and a gas inlet 111 is provided on the narrow surface of the rectangular parallelepiped. The gas enters the gas distribution pipe 121 through the gas inlet 111, and the air enters the first distribution chamber 12 through the air inlet 112. The first distribution chamber 12 can be rectangular. The air passes through the first flow balancing orifice 122, the second flow balancing orifice 123, and the outer side of the gas distribution pipe 121 in sequence and then mixes with the gas ejected from the second gas nozzle 1214. Then, the mixed gas passes through the spoiler column 125, the third flow balancing orifice 124 and the turning guide plate 126 to enter the second distribution chamber 13, and enters the burner water-cooled tube bundle under the action of the partition 131 and the distribution orifice 132. The air inlet 112 can be circular or square, the gas distribution pipe 121 can be a circular tube or a square tube, the first gas nozzle hole 1213 and the second gas nozzle hole 1214 can be circular holes, square holes or triangular holes. Preferably, two rows of staggered holes are arranged on the upper and lower sides of the second gas distribution pipe 1212. The first flow balancing orifice plate 122, the second flow balancing orifice plate 123, the third flow balancing orifice plate 124 and the distribution orifice plate 132 are provided with nozzles of various shapes and arrangements. The third flow balancing orifice plate 124 is arranged at the tail of the first distribution chamber 12, the turning guide plate 126 is connected to the third flow balancing orifice plate 124, the distribution orifice plate 132 is opposite to the planar heat exchange section 14, and the partition plate 131 is provided to separate the second distribution chamber 13 and change the flow area of ​​the second distribution chamber 13. The partition plate 131, the second flow balancing orifice plate 123 and the distribution orifice plate 132 surround the second distribution chamber 13.3 to 50 spoiler columns 125 are evenly arranged along the axial direction of the gas distribution pipe 121 behind the gas distribution pipe 121. The two ends of the spoiler column 125 are welded to the inner wall of the first distribution chamber 12. The spoiler column 125 is cylindrical, with a cross section of a triangle, an inverted triangle, a square or a circle. The turning guide plate 126 forms a 180° turn, with a cross section of a right-angle "U" shape, a smooth transition "U" shape or a "V" shape. The cross section of the second distribution chamber 13 is rectangular or trapezoidal. The second distribution chamber 13 is provided with a One to ten baffles 131 are positioned parallel to the flow direction of the mixed gas. The top of each baffle 131 may or may not connect to the top of the second distribution chamber 13; the bottom of each baffle 131 may or may not connect to the top of the distribution orifice plate 132; the left and right ends of each baffle 131 may or may not connect to the turning guide plate 126 and the end of the second distribution chamber 13, respectively. Distribution orifice plates 132 are positioned at the end of the second distribution chamber 13, and one to three layers of distribution orifice plates 132 may be provided. The flow area of ​​the first distribution chamber 12 along the direction of gas intake remains constant or gradually decreases, while the flow area of ​​the second distribution chamber 13 along the direction of mixed gas flow remains constant or gradually decreases. The gas flow directions in the first and second distribution chambers 12, 13 may be opposite, perpendicular, or at other angles. The corresponding turning guide plates 126 form a 180°, 90°, or other angle turn. The turning angle of the turning guide plates 126 can be set by one of ordinary skill in the art as needed. The burner 1 may be a low / zero carbon fuel burner. The low / zero carbon fuel may share a premixer with natural gas, or the low / zero carbon fuel and natural gas may be mixed with air separately.

[0104] Referring to Figures 7a, 7b, 8a and 8b, the water-cooled tube bundle at the head of the burner 1 is a membrane wall tube bundle. The membrane wall surface can be a flat surface, a curved surface or an arc surface. Two adjacent smooth tubes are welded together by flat steel. The flat steel is provided with regular premixed gas nozzles from bottom to top. The center lines of the nozzles are either vertical or inclined to the inner and outer planes of the flat steel so as to form high-temperature flue gas recirculation zones of varying degrees on the furnace surface. The airflow ejected by the premixed gas forms a built-in flue gas recirculation around the nozzle outlet to reduce NO x .

[0105] 5a, 5b and 6b, a triangular or V-shaped spoiler column 125 is provided at the front end of the gas distribution pipe 121. The cross section of the spoiler column 125 is parallel to the cross section of the first gas distribution pipe 1211. The cross section width of the spoiler column 125 may be greater than, equal to or less than the cross section width of the gas distribution pipe 121. The gas inlet 111 is located at one or both ends of the first gas distribution pipe 1211. Gas enters along the axis of the first gas distribution pipe 1211 from one or both ends. The air inlet 112 is located at the front end of the first distribution chamber 12. The first and second gas distribution pipes 1211, 1212 connect in the direction of air flow. First gas spray holes 1213 are evenly distributed at the interface between the first and second gas distribution pipes 1211, 1212. Second gas spray holes are evenly distributed at the top and bottom of the second gas distribution pipe 1212. The first gas spray holes 1213 are arranged in 1 to 8 rows, and the second gas spray holes 1214 are arranged in 1 to 4 rows. The first and second gas spray holes 1213, 1214 can be arranged in either sequential or staggered rows. Spoiler plates 1215 are welded to the top and bottom of the interface between the first and second gas distribution pipes 1211, 1212.

[0106] 4a, 4b and 4c, the burner forms of Schemes 1 and 2 are different in that the burner 1 of Schemes 3 and 4 includes a water-cooled tube bundle consisting of a burner inlet 11, a first distribution chamber 12, a second distribution chamber 13 and an arc-shaped heat exchange section 21 tube bundle.

[0107] 5a and 5c, when the mixed gas enters parallel to the distribution orifice plate 132, 1 to 10 vertical baffles parallel to the flow direction of the mixed gas are arranged in the second distribution chamber 13 along a direction perpendicular to the flow direction of the mixed gas. The leading edge of the vertical baffle is connected to the top of the second distribution chamber 13, and the trailing edge of the vertical baffle is connected to the distribution orifice plate 132 or is spaced 5 to 20 mm apart from the distribution orifice plate 132. The top and bottom ends of the vertical baffle are connected to the top and bottom surfaces of the second distribution chamber 13 respectively.

[0108] 5 b and 6 a , in the turning guide plate 126 , 0<W1<W, 0≤h1<h, and the position where the turning guide plate 126 is connected to the third flow averaging orifice plate 124 is adjustable.

[0109] The first equalizing orifice plate 122, the second equalizing orifice plate 123, the third equalizing orifice plate 124, the distribution orifice plate 132, the sealing plate 22, the upper furnace floor plate 24, the lower furnace floor plate 25, and the outer shell baffle 26 are all made of high-temperature and deformation-resistant materials. The surfaces of the parallel heat exchange tube bundle 142, the inner heat exchange tube bundle 212, and the radiation heating tube bundle 27 that come into direct contact with the high-temperature flue gas are spray-plated with nickel-chromium alloy. Burner 1 is a natural gas burner, a natural gas-blended low / zero carbon fuel burner, or a pure low / zero carbon fuel burner. The working medium of heat exchanger 2 is water or thermal oil.

[0110] The flow balancing and flow disturbing components in the burner 1 can be appropriately added, omitted or changed in position according to different working conditions.

[0111] Referring to Figures 6d and 6e, the first gas distribution pipe 1211 can also be placed parallel to the outside of the first distribution chamber 12. Three to twenty evenly spaced second gas distribution pipes 1212 have one end perpendicularly connected to the first gas distribution pipe 1211 and the other end extending into the first distribution chamber 12. One to three gas inlets 111 are located at one, both ends, or in the middle of the first gas distribution pipe 1211. The second gas distribution pipes 1212 have evenly spaced second gas nozzles 1214 arranged along the direction of air flow, away from the direction of air flow, or in both directions.

[0112] 4a, 4b, and 4c, when the burner 1 is disposed on the arc side of a semi-cylindrical furnace, one or two single-sided burners are arranged with an outer ring heat exchange tube bundle 213 and an inner ring heat exchange tube bundle 212 serving as water-cooled tube bundles. The burner 1 has a square front end and a crescent rear end in cross-section, and the distribution orifice plate 132 is arc-shaped. The diameter of the outer ring heat exchange tube bundle 213 is larger than that of the inner ring heat exchange tube bundle 212. The gap formed between adjacent tubes in the outer ring heat exchange tube bundle 213 is 2-5 mm, while the gap formed between adjacent tubes in the inner ring heat exchange tube bundle 212 is 4-10 mm. The number of rows of the outer ring heat exchange tube bundle 213 is the same as the number of nozzle rows in the distribution orifice plate 132, or the number of nozzle rows on the distribution orifice plate 132 is an integer multiple of the number of rows of the outer ring heat exchange tube bundle 213. The outer ring heat exchange tube bundle 213 and the nozzles on the distribution orifice plate 132 are directly opposite each other.

[0113] 3, 4, and 5, the gas-air mixture within the burner 1 can be introduced perpendicularly or parallel to the distribution orifice 132. When the gas is introduced perpendicularly to the distribution orifice 132, the turning guide plate 126 is not provided, and the flow direction of the gas mixture within the first distribution chamber 12 is the same as the direction in which the gas mixture is ejected from the second distribution chamber 13. When the gas is introduced parallel to the distribution orifice 132, the turning guide plate 126 is provided or not, and the flow direction of the gas mixture within the first distribution chamber 12 is perpendicular to the direction in which the gas is ejected from the second distribution chamber 13. The turning guide plate 126 is located at the junction of the first distribution chamber 12 and the second distribution chamber 13. The two sides of the turning guide plate 126 are connected to the two sides of the first distribution chamber 12 and the second distribution chamber 13. The cross-section is a right-angled "U" shape, a smoothly transitioned "U" shape, a "V" shape, an "L" shape, an "I" shape, etc.; when the turning guide plate 126 is in the "I" shape, the turning guide plate 126 is fixedly connected or hinged to the third flow balancing orifice plate 124. In the case of hinged connection, the turning guide plate can rotate 180°.

[0114] 5a and 5b, when the mixed gas enters parallel to the distribution orifice plate 132, 1 to 10 partitions parallel to the flow direction of the mixed gas are arranged in the second distribution chamber 13 along a direction perpendicular to the flow direction of the mixed gas. The top of the vertical partition is connected to the top of the second distribution chamber 13, and the bottom of the vertical partition is connected to the top of the distribution orifice plate 132 or is spaced 5 to 20 mm apart. The two ends of the vertical partition are respectively connected to the front end and the end of the second distribution chamber 13.

[0115] Referring to Figures 7a, 7b, 8a, and 8b, the water-cooled tube bundle of the burner head 1 is a membrane wall tube bundle. The membrane wall tube bundle is a tube bundle of a flat heat exchange section 14 and an arc heat exchange section 21. The membrane wall surface is a plane, an arc surface, or a curved surface. Two adjacent light tubes are welded by flat steel 16. The length direction of the flat steel 16 is parallel to the light tube row. The flat steel 16 is located on the center line of the light tube row or deviates from the center line of the light tube row. Accordingly, the flat steel 16 is welded to the light tube on both sides or on one side. The thickness of the flat steel 16 is The flat steel 16 has a thickness of 3 to 20 mm, and the arcuate surface in contact with the smooth tube in the thickness direction has a penetration depth of at least 3 mm. The weld 17 is as close to 100% penetration as possible. The flat steel 16 is provided with regular premixed gas nozzle holes 161 from bottom to top, with the center lines of the premixed gas nozzle holes being perpendicular or inclined to the flat steel 16. The premixed gas nozzle holes can be arranged in a single row, double rows, or three rows from bottom to top. When there are more than one row of premixed gas nozzle holes, the positions of the nozzle holes in adjacent rows are aligned or staggered. The premixed gas nozzle holes have a circular, oblong, triangular, or rectangular nozzle structure. The long axis of the oblong premixed gas nozzle hole is parallel to or perpendicular to the longitudinal centerline of the tube. The vertex angle of the triangular premixed gas nozzle hole is rotatable 360 ​​degrees, that is, the triangle can be arranged upright, inverted, or tilted. The long side of the rectangular premixed gas nozzle hole is parallel to or perpendicular to the longitudinal centerline of the tube.

[0116] Referring to Figures 10a, 10b, 10c, and 10d, the length direction of the flat steel 16 at the head of the burner 1 is perpendicular to the row of light tubes, and the flat steel 16 is located between two adjacent light tubes. The head of the burner 1 has at least two rows of light tubes. The flat steel 16 is welded to the first row of light tubes 1421, forming a narrow gap between the second row of light tubes 1422. Flat steel fins 163 with evenly arranged arc or rectangular surfaces can be welded on the flat steel 16; or pads 162 are evenly welded on the flat steel, and the cross-section of the pads 162 is square, circular, or oblong. The pads 162 are welded to the row of light tubes through the pads 162, and evenly arranged premixed gas nozzles are formed between the light tubes, the pads 162, and the flat steel 16. The head of the burner 1 has at least one row of light tubes. An adjustable spray hole baffle 18 is used to partially block the nozzle formed by the premixed gas spray hole 161 or the pad 162. The adjustable spray hole baffle 18 is provided with a spray hole of the same size and position as the premixed gas spray hole or the pad nozzle. The adjustable spray hole baffle 18 slides axially along the membrane wall tube, and the sliding range can cover the nozzle formed by the premixed gas spray hole 161 or the pad 162, refer to Figures 11a, 11b, and 11c.

[0117] Referring to Figures 9a, 9b, and 9c, and Figures 12a, 12b, 12c, 12d, 12e, and 12f, the flat steel 16 at the head of the burner 1 can be channel steel, I-beam, curved steel, angle steel, small round tube, or semicircular tube. For curved steel, the curvature α is 0 < α < π, and for angle steel, the angle β is 0 < β < 180°. The water-cooled tube bundle at the head of the burner 1 can also be a combination of finned tubes and plain tubes, with the finned tubes having opposite sides bent or not bent, and the plain tube sides facing or away from the furnace. The finned tubes can be spiral finned tubes, circular finned tubes, square finned tubes, or H-shaped finned tubes.

[0118] Referring to Figures 2a, 2b, 2d and 2e, one or two ignition needles 15 are arranged on each combustion surface. The ignition needles 15 can be extended into the furnace from the side, top or bottom of the furnace. The ignition needles 15 correspondingly pass through the sealing plate 22 or the upper bottom plate 24 or the lower bottom plate 25 of the furnace and extend into the furnace. The ignition needles 15 are 10-50 mm away from the outer wall of the side-by-side heat exchange tube bundle 142 or the outer wall of the inner ring heat exchange tube bundle 212.

[0119] Referring to Figures 1a, 1b, 3a, 3b, 3c, and 3d, when the burner is arranged on the chord side of the semi-cylindrical furnace, a double-sided burner or two single-sided burners are arranged with a side-by-side heat exchange tube bundle as a water-cooled tube bundle, and the burner flow area gradually decreases from the burner inlet to the burner end; when one double-sided burner is arranged, the burner takes in air on one side along the direction of the semi-cylindrical furnace chord and exhausts air on both sides perpendicular to the air intake direction, and the burner is symmetrical along the axis perpendicular to the air intake direction; when two single-sided burners are arranged, the burners take in air on both sides or one side along the direction of the semi-cylindrical furnace chord and exhaust air on both sides perpendicular to the air intake direction, and the burners are centrally symmetrical or axially symmetrical.

[0120] Referring to Figures 1a, 1b, 1c, 1d, 1e, 13, 14a, 14b, and 14c, the flue 3 includes a flue gas header 31, a flue gas duct 32, and a flue gas outlet 33. When the burner 1 is positioned on the chord side of a semi-cylindrical furnace, it is a double flue. The two flue gas headers 31 are connected via the flue gas duct 32. The flue gas in the two flue gas headers 31 is collected by the flue gas duct 32 and discharged from the flue gas outlet 33. When the burner 1 is positioned on the arc side of a semi-cylindrical furnace, it is a single flue. The flue gas in the flue gas header 31 is directly discharged from the flue gas outlet 33. The flue gas outlet 33 is sequentially connected to the economizer 4, condenser 5, and chimney 6. The outlet of the fan 7 is connected to any of the front, left, right, or top surfaces of the burner 1, and the narrow surface of the fan 7 is parallel to the surface connected to the burner 1.

[0121] Gas and air enter the burner 1 through the gas inlet 111 and the air inlet 112 respectively for equal flow and mixing, and are ignited and burned in the furnace space surrounded by the burner 1, the heat exchanger 2, the flue 3 and the outer shell baffle 26. The high-temperature flue gas generated by the combustion exchanges heat with the parallel heat exchange tube bundle 142, the radiation heating tube bundle 27, the inner ring heat exchange tube bundle 212 and the outer ring heat exchange tube bundle 213, and is then discharged from the flue 3 and enters the economizer 4 and the condenser 5 for further heat exchange. The flue gas is then discharged from the chimney 6. Water is first pumped into the condenser 5 and economizer 4 by a water pump. After absorbing sensible and latent heat from the flue gas, it enters the water inlet of the annular upper header 211. The cold water then enters the annular lower header 215 through the downcomer 214. The water in the annular lower header 215 enters the annular upper header 211 through the inner heat exchange tube bundle 212, the outer heat exchange tube bundle 213, or the radiation heating tube bundle 27, or enters the annular upper header 211 through the tubular lower header 143, the side-by-side heat exchange tube bundle 142, and the tubular upper header 141 in sequence. The water in the inner heat exchange tube bundle 212, the outer heat exchange tube bundle 213, the radiation heating tube bundle 27, and the side-by-side heat exchange tube bundle 142 absorbs furnace radiation heat and flue gas convection heat, causing the water temperature to rise and generate steam. The steam enters the annular upper header 211 and is discharged through the steam outlet for consumption, thus forming a natural circulation boiler. Alternatively, the downcomer 214 is not provided, and cold water enters directly from the water supply port on the annular lower header 215, enters the heated tube bundle to absorb heat, and then enters the annular upper header 211 to generate steam or hot water for users. In this case, it is a cross-flow boiler.

[0122] In summary, the present invention describes a vertical water tube built-in premixed membrane wall-cooled combustion gas boiler comprising a burner "furnace", a heat exchanger "pot", a flue, an economizer, a condenser, a chimney and matching boiler accessories such as a fan, a water pump, a gas valve group, and a controller; the burner and the heat exchanger or both are swapped, and two axially symmetrical semi-cylindrical furnaces are formed by two side-by-side heat exchange tube bundles and two to three circles of water-cooled tube bundles. The burner adopts two relative planes or semicircular surfaces of premixed membrane wall water-cooled combustion, and the flue gas after combustion flushes the two relative heat exchange areas. The present invention has a compact structure, low resistance, and high heat exchange efficiency; at the same time, the premixed water-cooled combustion temperature is low, the load is uniform, the adjustment ratio is large, and NO x Extremely low emissions; anti-explosion, high safety, suitable for pure natural gas combustion or natural gas and low / zero carbon fuel combustion or pure low / zero carbon fuel combustion.

[0123] In addition, compared with traditional vertical water-tube steam boilers, the burner and heat exchanger of the present invention are connected to the upper annular header and the lower annular header using whole or partly detachable flanges, so the burner and heat exchanger can be inspected offline at the same time, which significantly improves the maintainability of the burner and heat exchanger.

Claims

1. A vertical water tube built-in premixed membrane wall-cooled burner, characterized in that: The invention comprises a first distribution chamber (12), a second distribution chamber (13) and a water-cooled tube bundle, wherein the first distribution chamber (12) is provided with an air inlet (112), a gas distribution pipe (121) is provided in the first distribution chamber (12), and the gas distribution pipe (121) has a gas inlet (111); the first distribution chamber (12) is connected to the second distribution chamber (13); the second distribution chamber (13) comprises a partition plate (131) and a distribution orifice plate (132), one end of the partition plate (131) is connected to the first distribution chamber (12), and the other end is connected to the distribution orifice plate (132); the vertical area surrounded by the partition plate (131) and the distribution orifice plate (132) is the second distribution chamber (13), and the distribution orifice plate (132) is directly opposite to the water-cooled tube bundle, and the water-cooled tube bundle is a membrane wall tube bundle, and air flow holes are provided on the membrane wall tube bundle, and the membrane wall surface is a plane, an arc surface or a curved surface.

2. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 1 is characterized in that: A first flow balancing orifice plate (122) and a plurality of spoiler columns (125) are arranged in the first distribution chamber (12); a second flow balancing orifice plate (123) is arranged between the first distribution chamber (12) and the second distribution chamber (13); a gas distribution pipe (121) is arranged between the first flow balancing orifice plate (122) and the second flow balancing orifice plate (123); spoiler columns (125) are arranged in front of and behind the first flow balancing orifice plate (122); the spoiler columns (125) are arranged along the length direction of the gas distribution pipe (121); both ends of the spoiler columns (125) are connected to the first distribution chamber (12); the cross section of the spoiler columns (125) is triangular, V-shaped, square or circular; in the case of a V-shaped cross section, the bending angle of the V-shape faces the incoming air; and 3 to 50 spoiler columns (125) are arranged.

3. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 1, characterized in that: The gas distribution pipe (121) comprises a first gas distribution pipe (1211), a second gas distribution pipe (1212), a first gas spray hole (1213), a second gas spray hole (1214) and a spoiler (1215); a gas inlet (111) is provided at one or both ends of the first gas distribution pipe (1211), the first gas distribution pipe (1211) is connected to the second gas distribution pipe (1212), and a first gas spray hole (1213) is evenly provided on the gas outlet surface of the first gas distribution pipe (1211). holes (1213), second gas spray holes are evenly opened on the side of the second gas distribution pipe (1212); the first gas spray holes (1213) are arranged in 1 to 8 rows, and the second gas spray holes (1214) are arranged in 1 to 4 rows, the first gas spray holes (1213) are arranged in series or staggered rows, and the second gas spray holes (1214) are arranged in series or staggered rows; spoilers (1215) are welded at the top and bottom of the interface between the first gas distribution pipe (1211) and the second gas distribution pipe (1212).

4. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 3 is characterized in that: The flow area in the first gas distribution pipe (1211) along the gas intake direction remains unchanged or gradually decreases, and the flow area in the second distribution chamber (13) along the mixed gas flow direction remains unchanged or gradually decreases.

5. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 3 is characterized in that: The first gas distribution pipe (1211) is horizontally arranged above the first distribution chamber (12); one end of 3 to 20 evenly arranged second gas distribution pipes (1212) is vertically connected to the first gas distribution pipe (1211), and the other end extends into the first distribution chamber (12); the gas inlet (111) is located at one end, both ends and / or the middle of the first gas distribution pipe (1211); 1 to 3 gas inlets (111) are provided; and evenly arranged second gas spray holes (1214) are provided on the second gas distribution pipe (1212) along the air flow direction or away from the air flow direction or in both directions.

6. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 1, characterized in that: The mixed gas of the fuel gas and the air in the burner (1) is fed perpendicularly to the distribution orifice plate (132) or parallel to the distribution orifice plate (132), and the distribution orifice plate (132) is provided in 1 to 3 layers; a third flow balancing orifice plate (124) is provided at the tail of the first distribution chamber (12), and a turning guide plate (126) is provided when the gas is fed parallel to the distribution orifice plate (132), and the turning guide plate (126) is located at the junction of the first distribution chamber (12) and the second distribution chamber (13). , the turning guide plate (126) is connected to the third flow balancing orifice plate (124); the two sides of the turning guide plate (126) are connected to the two sides of the first distribution chamber (12) and the second distribution chamber (13), and the cross section is a right-angle "U" shape, a smoothly transitioned "U" shape, a "V" shape, an "L" shape, or an "I" shape; when the turning guide plate (126) is in an "I" shape, the turning guide plate (126) is fixedly connected or hinged to the third flow balancing orifice plate (124).

7. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 1, characterized in that: When the mixed gas is introduced parallel to the distribution orifice plate (132), 1 to 10 vertical partitions parallel to the flow direction of the mixed gas are arranged in the second distribution chamber (13) along a direction perpendicular to the flow direction of the mixed gas, the front edge of the vertical partition is connected to the top of the second distribution chamber (13), the rear edge of the vertical partition is connected to the distribution orifice plate (132) or is spaced 5 to 20 mm from the distribution orifice plate (132), and the top and bottom ends of the vertical partition are respectively connected to the top surface and bottom surface of the second distribution chamber (13).

8. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 1, characterized in that: The membrane wall tube bundle comprises a plurality of light tubes, two adjacent light tubes are welded by flat steel (16), the length direction of the flat steel (16) is parallel to the light tube row, the flat steel (16) is located on the center line of the light tube row or deviates from the center line of the light tube row, and the flat steel (16) is welded to the light tube on both sides or on one side accordingly; the thickness of the flat steel (16) is 3 to 20 mm, and the welding penetration of the arc surface of the flat steel (16) in the thickness direction in contact with the light tube is at least 3 mm, and the flat steel (16) is provided with regular premixed gas spray holes (161) from bottom to top, i.e., the gas The flow holes, the center lines of the premixed gas spray holes (161) are perpendicular or inclined to the plane of the flat steel (16), the premixed gas spray holes (161) are in a single row, double rows or three rows, when there are more than one row of premixed gas spray holes (161), two adjacent rows of premixed gas spray holes are arranged in a row or staggered row, the premixed gas spray holes (161) are circular, oblong, triangular or rectangular; the long axis of the oblong premixed gas spray holes is parallel to or perpendicular to the longitudinal center line of the tube; the triangular premixed gas spray holes are arranged upright, inverted or inclined, and the long side of the rectangular premixed gas spray holes is parallel to or perpendicular to the longitudinal center line of the tube.

9. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 1, characterized in that: The water-cooling tube bundle comprises at least two rows of light tubes, a flat steel (16) is welded to the first row of light tubes (1421), the flat steel (16) is located between the second row of light tubes (1422) and forms a gap with the second row of light tubes (1422), and evenly arranged flat steel fins (163) or pads (162) are welded to the flat steel (16); the flat steel fins (163) are arcuate or rectangular, the pads (162) have a square, circular or oblong cross section, and the pads (162) and the second row of light tubes (1422) are connected to each other. Welding is performed to form uniformly arranged air flow holes between the light tube, the cushion block (162) and the flat steel (16); an adjustable spray hole baffle (18) is provided on the flat steel (16) to block the premixed gas spray hole (161) or the air flow hole formed by the cushion block (162); the adjustable spray hole baffle (18) is provided with a premixed gas spray hole (161) having the same size and position as the air flow hole; the adjustable spray hole baffle (18) slides along the axial direction of the membrane wall tube, and the sliding range can cover the premixed gas spray hole (161).

10. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 1, characterized in that: The membrane wall tube bundle includes multiple smooth tubes, and channel steel, I-beam, arc steel, angle steel, small round tube or semi-circular tube are welded between the smooth tubes. When arc steel is welded between the smooth tubes, the curvature α of the arc steel is: 0<α<π, and when angle steel is welded between the smooth tubes, the angle β of the angle steel is: 0<β<180°.

11. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 1, characterized in that: The membrane wall tube bundle is a combination of fin tubes and smooth tubes. The fin tubes are bent on opposite sides, the smooth tubes face the furnace or face away from the furnace, and the fin tubes are spiral fin tubes, circular fin tubes, square fin tubes or H-shaped fin tubes.

12. A vertical water tube built-in premixed membrane wall-cooled combustion gas boiler, characterized in that: The invention comprises a burner (1), a heat exchanger (2), a flue (3), an economizer (4), a condenser (5), a chimney (6) and a fan (7); the burner (1) and the heat exchanger (2) enclose two axially symmetrical semi-cylindrical furnaces, and two heating surfaces, a plane heat exchange section (14) and an arc-shaped heat exchange section (21), are arranged in the furnaces; the burner (1) is arranged on the chord side of the semi-cylindrical furnace, and the heat exchanger (2) is arranged on the arc side of the semi-cylindrical furnace, or the burner (1) is arranged on the arc side of the semi-cylindrical furnace, and the heat exchanger (2) is arranged on the chord side of the semi-cylindrical furnace, or the burner (1) and the heat exchanger (2) are respectively arranged on the arc sides of two semi-cylindrical furnaces; the burner (1) adopts premixed water cooling A burner, wherein a tube bundle of a planar heat exchange section (14) or an arc-shaped heat exchange section (21) is used as a water-cooled tube bundle of the burner (1); when the burner (1) is located on the chord side of a semi-cylindrical furnace, the flue gases of the two semi-cylindrical furnaces flow toward the outside of the cylinder respectively; when the burner (1) is located on the arc side of the semi-cylindrical furnace, the two semi-cylindrical furnaces are connected, and the flue gases flow into the cylinder or flow into the cylinder from one side and out from the other side; the burner (1), the heat exchanger (2), the flue (3), the economizer (4), the condenser (5) and the chimney (6) are connected along the direction of the flue gas flow; the burner (1) adopts the vertical water tube built-in premixed membrane wall-cooled burner as described in any one of claims 1 to 12.

13. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 12, characterized in that: The planar heat exchange section (14) comprises a tubular upper header (141), a parallel heat exchange tube bundle (142) and a tubular lower header (143); the two ends of the parallel heat exchange tube bundle (142) are respectively connected to the tubular upper header (141) and the tubular lower header (143); the arc-shaped heat exchange section (21) comprises an annular upper header (211), an inner ring heat exchange tube bundle (212), an outer ring heat exchange tube bundle (213) and an annular lower header (215); the outer ring heat exchange tube bundle (213) and the inner ring heat exchange tube bundle (21 2) arranged along a semi-cylindrical surface, with the outer heat exchange tube bundle (213) and the inner heat exchange tube bundle (212) connected at both ends to an annular upper header (211) and an annular lower header (215); the outer heat exchange tube bundle (213) and the inner heat exchange tube bundle (212) are arranged in staggered rows; the bottom end of the annular upper header (211) and the top end of the annular lower header (215) are respectively sealedly connected to a furnace upper bottom plate (24) and a furnace lower bottom plate (25); and an outer shell baffle (26) is arranged outside the two semi-cylindrical furnaces.

14. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 13, characterized in that: When the maximum distance between the tubular upper header (141) and the tubular lower header (143) is smaller than the distance between the bottom of the annular upper header (211) and the top of the annular lower header (215), the burner (1) is integrally detachable, and the tubular upper header (141) and the tubular lower header (143) are provided with a tubular header steam outlet (145) and a tubular header water inlet (144) at both ends of the axial direction, respectively. The tubular header steam outlet (145) and the tubular header water inlet (144) are connected to a connecting pipe (29) via a flange. The connecting pipe (29) is a 180° elbow, one end of which is tightly connected to a flange on the tubular upper header (141) or the tubular lower header (143), and the other end is connected to the outer side of the annular upper header (211) or the annular lower header (215); the space between the tubular upper header (141) and the tubular lower header (143) is When the maximum distance is greater than the distance between the bottom of the annular upper header (211) and the top of the annular lower header (215), the burner (1) is partially detachable, and the remaining burner (1) parts except the tubular upper header (141), the parallel heat exchange tube bundle (142) and the tubular lower header (143) can be pulled out in the horizontal direction; the two ends of the axis of the tubular upper header (141) and the tubular lower header (143) are respectively connected to the annular upper header (211) and the annular lower header (215), and the connection parts are the inner side surface or the top of the annular upper header (211) and the inner side surface or the bottom of the annular lower header (215); the detachable part of the burner (1) is connected and sealed with the annular upper header (211), the annular lower header (215), the furnace upper bottom plate (24), the furnace lower bottom plate (25) and the shell baffle (26) by using a drawer structure.

15. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 13, characterized in that: When the burner (1) is arranged on the chord side of the semi-cylindrical furnace, a flat heat exchange section (14) tube bundle is used as a water-cooling tube bundle of the burner (1), and the flue (3) is arranged outside the arcuate surfaces of the two semi-cylindrical furnaces; when the burner (1) is arranged on the arcuate side of the semi-cylindrical furnace, an outer ring heat exchange tube bundle (213) and an inner ring heat exchange tube bundle (212) arranged along the semi-cylindrical surface are used as the water-cooling tube bundle of the burner, and the flue (3) is arranged on the side between the two semi-cylindrical furnaces or outside the other arcuate surface of the semi-cylindrical furnace.

16. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 13, characterized in that: A downcomer (214) is arranged on the periphery of the heating surface of the heat exchanger (2), and two ends of the downcomer (214) are connected to an annular upper header (211) and an annular lower header (215), thereby forming a natural circulation steam boiler.

17. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 13, characterized in that: A radiation heating tube bundle (27) is arranged in the semi-cylindrical furnace. The radiation heating tube bundle (27) is inwardly concave around a circumference and is divided into three sections: an upper inclined section, a middle vertical section, and a lower inclined section. The three sections of a radiation heating tube are located in the same plane. The upper inclined section and the lower inclined section face the same direction. The top of the radiation heating tube bundle (27) is connected to the inner side or the top of the annular upper header (211), and the bottom of the radiation heating tube bundle (27) is connected to the inner side or the bottom of the annular lower header (215). The radiation heating tube bundle (27) is evenly arranged along the circumferential direction. The 2-5 radiation heating tube bundles (27) on both sides of the burner (1) have shortened upper inclined sections and lower inclined sections.

18. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 13, characterized in that: The vertical cross-sections of the annular upper header (211) and the annular lower header (215) are rectangular, circular or elliptical with chamfered corners or rounded arcs on all sides. Two to three circles of vertical heat exchange tube bundles are arranged between the annular upper header (211) and the annular lower header (215). The inner circle heat exchange tube bundle (212) close to the furnace is a plain tube, a spiral fin tube or a fin tube. When the inner circle heat exchange tube bundle (212) is a spiral fin tube, the fin height is less than 10 mm. When the inner circle heat exchange tube bundle (212) is a fin tube, the fin height is less than 10 mm. The outer ring heat exchange tube bundle (213) is a reinforced heat exchange tube bundle of a spiral finned tube, a finned tube or a special-shaped tube structure, and the height of the fins is 30 to 100 mm; an annular header water inlet (216) is provided below the steam-water dividing line on the side of the annular upper header (211) or at the bottom, and an annular header steam outlet (217) is provided above the steam-water dividing line on the side of the annular upper header (211) or at the top; a sewage outlet (218) is provided on the side or at the bottom of the annular lower header (215).

19. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 13, characterized in that: One to three circles of tube bundles are arranged at the arc-shaped heat exchange section (21), and the cross section formed by the tube bundles of the arc-shaped heat exchange section (21) is arc-shaped, trapezoidal or "V"-shaped. One to two rows of smooth tubes, spiral fin tubes, special-shaped tubes and / or slit guide plates (23) are arranged at the parallel heat exchange tube bundles (142); a slit guide plate (23) is arranged between two adjacent heat exchange tubes of the outer circle heat exchange tube bundle (213), and the slit guide plate (23) is located at the outer circle. The inner side of the heat exchange tube bundle (213); or a slit guide plate (23) is arranged between two adjacent heat exchange tubes in the inner heat exchange tube bundle (212), and the slit guide plate (23) is located outside the inner heat exchange tube bundle (212); or slit guide plates (23) are arranged in both the outer heat exchange tube bundle (213) and the inner heat exchange tube bundle (212); and an enhanced heat exchange channel is formed between the slit guide plate (23) and the outer wall of the heat exchange tube.

20. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 13, characterized in that: The two heat exchange tubes at both ends of the inner ring heat exchange tube bundle (212) and the outer ring heat exchange tube bundle (213) are both configured as bare tubes. A sealing tube (28) is provided between the bare tube and the tube bundles at both ends of the parallel heat exchange tube bundle (142). The sealing tube (28) is a bare tube. The sealing tube (28) is tangent to the tube bundles at both ends of the parallel heat exchange tube bundle (142). Both ends of the sealing tube (28) are respectively connected to the annular upper header (211) and the annular lower header (215). Bend structures are provided at both ends of the sealing tube (28). A sealing plate (22) is provided to seal the longitudinal gap between the two bare tubes at the same end of the inner ring heat exchange tube bundle (212) and the outer ring heat exchange tube bundle (213), the sealing tube (28), and one end or both ends of the parallel heat exchange tube bundle (142) when the burner (1) is located on the arc side of the semi-cylindrical furnace.

21. The vertical water tube built-in premixed membrane wall-cooled burner according to claim 12, characterized in that: The first flow balancing orifice plate (122), the second flow balancing orifice plate (123), the third flow balancing orifice plate (124), the distribution orifice plate (132), the sealing plate (22), the furnace upper bottom plate (24), the furnace lower bottom plate (25) and the outer shell baffle (26) are all made of high temperature resistant and deformation resistant materials; the tube bundle surfaces of the parallel heat exchange tube bundle (142), the inner ring heat exchange tube bundle (212) and the radiation heating tube bundle (27) that are in direct contact with the high temperature flue gas are sprayed with nickel-chromium alloy; the burner (1) is a natural gas burner, a natural gas mixed with low / zero carbon fuel burner or a pure low / zero carbon fuel burner; and the working medium of the heat exchanger (2) is water or heat transfer oil.

22. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 12, characterized in that: When the burner (1) is arranged on the side of the semi-cylindrical furnace chord, a double-sided burner or two single-sided burners are arranged with a side-by-side heat exchange tube bundle (142) as a water-cooled tube bundle, and the flow area of ​​the burner (1) gradually decreases from the burner inlet to the burner end; when a double-sided burner is arranged, the burner (1) takes in air on one side along the direction of the semi-cylindrical furnace chord, and exhausts air on both sides perpendicular to the air intake direction, and the burner (1) is symmetrical along the axis perpendicular to the air intake direction; when two single-sided burners are arranged, the burner (1) takes in air on both sides or takes in air on one side along the direction of the semi-cylindrical furnace chord, and exhausts air on both sides perpendicular to the air intake direction, and the burner (1) is centrally symmetrical or axisymmetric.

23. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 12, characterized in that: When the burner (1) is arranged on the arc side of a semi-cylindrical furnace, one or two single-sided burners are arranged with the outer ring heat exchange tube bundle (213) and the inner ring heat exchange tube bundle (212) as water-cooled tube bundles, the front end of the cross section of the burner (1) is square, the rear end is crescent-shaped, and the distribution orifice plate (132) is arc-shaped; the diameter of the outer ring heat exchange tube bundle (213) is larger than the diameter of the inner ring heat exchange tube bundle (212); the gap formed between adjacent tubes of the outer ring heat exchange tube bundle (213) is 2-5 mm, and the gap formed between adjacent tubes of the inner ring heat exchange tube bundle (212) is 4-10 mm; the number of columns of the outer ring heat exchange tube bundle (213) is the same as the number of columns of spray holes on the distribution orifice plate (132) or the number of columns of spray holes on the distribution orifice plate (132) is an integer multiple of the number of columns of the outer ring heat exchange tube bundle (213), and the spray holes on the outer ring heat exchange tube bundle (213) and the distribution orifice plate (132) are directly opposite.

24. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 12, characterized in that: The flue (3) comprises a flue gas header (31), a flue gas duct (32) and a flue gas outlet (33). When the burner (1) is arranged on the chord side of the semi-cylindrical furnace, it is a double flue. The two flue gas headers (31) are connected via the flue gas duct (32). The flue gas in the two flue gas headers (31) is collected via the flue gas duct (32) and discharged from the flue gas outlet (33). When the burner (1) is arranged on the arc side of the semi-cylindrical furnace, it is a single flue. The flue gas in the flue gas header (31) is directly discharged from the flue gas outlet (33). The flue gas outlet (33) is connected to the economizer (4), the condenser (5) and the chimney (6) in sequence. The outlet of the fan (7) is connected to the burner (1), and the narrow surface of the fan (7) is parallel to the corresponding connection surface of the burner (1).

25. The vertical water tube built-in premixed membrane wall-cooled combustion gas boiler according to claim 12, characterized in that: One or two ignition needles (15) are arranged on each combustion surface. The ignition needles (15) can extend into the furnace from the side, top or bottom of the furnace. The ignition needles (15) correspondingly pass through the sealing plate (22) or the upper bottom plate (24) or the lower bottom plate (25) of the furnace and extend into the furnace. The ignition needles (15) are 10-50 mm away from the outer wall of the parallel heat exchange tube bundle (142) or the outer wall of the inner circle heat exchange tube bundle (212).

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