Bridge opening type combustion reheating ultra-low nitrogen steam generator

Abstract

The bridge opening type combustion reheating ultra-low nitrogen steam generator comprises a first outer frame, a second outer frame, a third outer frame and a fourth outer frame which are sequentially arranged from left to right, a combustor for generating high-temperature smoke is fixedly installed on the upper end face of the first outer frame, and the exhaust portion of the combustor is communicated with the interior of the first outer frame; a coil pipe type direct-flow hearth and a plurality of communicated convection banks are fixedly installed in the first outer frame, the convection banks are of a vertical tubular structure, a first reheat steam pipe and a steam pocket tank are fixedly installed in the second outer frame, and a plurality of second reheat steam pipes are connected to the lower portion of the steam pocket tank. A plurality of vertical tubular reheat steam pipes III are fixedly mounted in the outer frame III; and a plurality of condenser pipes which are communicated with one another are fixedly arranged in the outer frame IV. In the saturated steam production process, purified water is subjected to multiple times of heating treatment, high-temperature flue gas generated by the combustor can be efficiently utilized, heat loss is reduced, and the heat energy conversion efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of steam generating equipment, and in particular relates to a bridge hole type combustion reheating ultra-low nitrogen steam generator. Background Art

[0002] A steam generator, also known as a steam heat source machine, is a mechanical device that uses the thermal energy of fuel or other energy sources to heat water into hot water or steam. The original meaning of a pot refers to a water container heated on fire, and a furnace refers to a place where fuel is burned. A boiler consists of two major parts: a pot and a furnace. A steam generator is sometimes called a steam boiler. It is an important part of a steam power plant. Power station boilers, steam turbines and generators are the main machines of a thermal power station. Therefore, power station boilers are important equipment for producing electricity. With the development of science and technology, steam generators are becoming more and more perfect.

[0003] In the prior art, such as Chinese Patent Publication No.: CN116105116A, a fully premixed ultra-low nitrogen gas steam generator is disclosed, which includes a base, an outer frame is fixedly installed on the outer side of the top of the base, a movable door is rotatably installed on the left side of the outer frame, a support seat is fixedly installed on the right side of the top of the base, and a water pump is fixedly installed on the left side of the top of the base.

[0004] The steam generator mixes fuel and air through a burner and ignites it to produce high-temperature and high-pressure flue gas. These flue gases pass through the heat exchanger or the water pipe wall in the boiler body, transferring heat to the water, causing it to gradually heat, evaporate and convert into steam. The steam generators in the above-mentioned comparative documents lack efficient utilization of high-temperature exhaust gas, resulting in low thermal efficiency and lack of further treatment of high-temperature flue gas. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a bridge-hole combustion reheating ultra-low nitrogen steam generator, which can fully utilize high-temperature flue gas, reduce heat loss, and improve thermal energy conversion efficiency.

[0006] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a bridge-hole type combustion reheat ultra-low nitrogen steam generator, comprising an outer frame 1, an outer frame 2, an outer frame 3 and an outer frame 4 arranged in sequence from left to right, a burner for generating high-temperature flue gas is fixedly installed on the upper end surface of the outer frame 1, and the exhaust part of the burner is communicated with the interior of the outer frame 1, and a coil-type direct current furnace and a plurality of connected convection tube bundles are fixedly installed in the outer frame 1, the coil-type direct current furnace is a section of spiral pipe, the convection tube bundle is a vertical tubular structure, and the plurality of convection tube bundles are connected. The outer frame 2 is fixedly connected through a plurality of connecting elbows, a reheat steam pipe 1 and a steam drum body are fixedly installed in the outer frame 2, the steam drum body is located on the right side of the reheat steam pipe 1, one end of the reheat steam pipe 1 is connected to the steam drum body, and the other end is fixedly connected to a steam exhaust pipe, a plurality of reheat steam pipes 2 are connected to the bottom of the steam drum body, a plurality of vertical tubular reheat steam pipes 3 are fixedly installed in the outer frame 3, a flue gas outlet communicating with the outside is provided at the lower end of the outer frame 4, and a plurality of condensing pipes connected to each other are fixedly arranged in the outer frame 4.

[0007] Optionally, spiral heat absorbing sheets for absorbing heat from high-temperature flue gas are fixedly provided on the surfaces of the convection tube bundle, the second reheat steam tube and the third reheat steam tube.

[0008] Optionally, the outer frame one, outer frame two, outer frame three and outer frame four are fixedly connected to each other by bolts, and the interiors of the outer frame one, outer frame two, outer frame three and outer frame four are connected.

[0009] Optionally, the outer end of the lower condenser is fixedly connected to a water inlet pipe, the outer end of the upper condenser is fixedly connected to a water supply pipe three, the upper end of the water supply pipe three is fixedly connected to a pipe three via a flange, a water storage tank is fixedly installed on the upper end surface of the outer frame three, the water storage tank is connected to the upper end pipe openings of several reheat steam pipes three, and the lower end of the pipe three extends into the water storage tank and communicates with the water tank.

[0010] Optionally, a plurality of connecting pipes are fixedly provided at the lower end of the reheat steam pipe three, and the plurality of connecting pipes pass through the outer frame two and are fixedly fitted therewith. A water inlet one is provided at the lower end of the coil-type direct current furnace, and a pipe four is fixedly connected between the plurality of connecting pipes and the water inlet one.

[0011] Optionally, some of the convection tube bundles have two pipe openings communicating with the outside, one of which is fixedly installed with a water pipe 1, the other end of which is connected to the upper pipe opening of the coil-type direct current furnace through a flange, and the outlet on the other side is fixedly connected with a water pipe 2, the other end of which is connected to the steam drum tank body.

[0012] Optionally, a drainage tank fixed to the outer surface of the outer frame 2 is provided directly below the steam drum tank body, the lower end of the drainage tank is connected to the pipeline 1, the two ends of the reheated steam pipe 2 are respectively connected to the steam drum tank body and the drainage tank, and a steam-water separator is fixedly provided near the upper part of the steam drum tank body.

[0013] Optionally, the upper end of the reheat steam pipe 1 is provided with two pipe openings, one of which is fixedly connected to a steam input pipe, and the other is fixedly connected to a steam output pipe, one end of the steam input pipe passes through the steam drum tank and the steam-water separator, and the upper end of the steam input pipe is located above the steam-water separator.

[0014] In summary, compared with the prior art, the bridge-hole combustion reheat ultra-low nitrogen steam generator provided by the present invention has the following beneficial effects: 1. In the present invention, in the process of producing saturated steam, the purified water is subjected to multiple heating treatments, which can efficiently utilize the high-temperature flue gas generated by the burner, reduce heat loss, and improve heat energy conversion efficiency; 2. In the present invention, by arranging spiral heat absorbing sheets for absorbing the heat of high-temperature flue gas on the surfaces of the convection tube bundle, the second reheat steam tube and the third reheat steam tube, the high-temperature flue gas flowing in the second outer frame and the third outer frame can be efficiently utilized, thereby effectively improving the heating effect of purified water; 3. In the present invention, the high-temperature flue gas generated by the burner will enter the outer frame 2 through the outer frame 1, then enter the outer frame 3, and finally enter the outer frame 4. During this period, the heat of the high-temperature flue gas is absorbed layer by layer. Finally, the high-temperature flue gas is cooled by the condenser in the outer frame 4, which can greatly reduce the temperature of the exhausted flue gas, reduce the exhaust loss, and thus the thermal efficiency of the device will be higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The internal structure of the present invention is shown in side view Figure 1 ; Figure 2 The external structure of the present invention is shown in FIG. Figure 1 ; Figure 3 The internal structure of the present invention is shown in side view Figure 2 ; Figure 4 The structure of the present invention is schematically shown Figure 2 ; Figure 5 It is a schematic diagram of the structure of the convection tube bundle of the present invention; Figure 6 For the present invention Figure 5 A detailed enlarged picture of point A; In the figure: 1, burner; 2, coil-type direct current furnace; 21, water inlet 1; 22, pipeline 4; 3, convection tube bundle; 31, spiral heat absorber; 311, connecting elbow; 32, water pipe 1; 33, water pipe 2; 4, reheat steam pipe 1; 41, steam input pipe; 42, steam output pipe; 421, steam outlet; 5, steam drum; 51, steam-water separator; 52, pipeline 1; 5 21. Wastewater outlet; 53. Reheat steam pipe 2; 54. Drain tank; 6. Water level gauge; 63. Pipe 2; 64. Pipe 3; 641. Water storage tank; 71. Outer frame 1; 72. Outer frame 2; 73. Outer frame 3; 74. Outer frame 4; 8. Condenser; 81. Water inlet pipe; 82. Condenser pipe; 83. Water pipe 3; 84. Flue gas outlet; 91. Reheat steam pipe 3; 92. Multi-port connecting pipe. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0017] Embodiment 1: refer to Figure 1-2 A bridge hole type combustion reheat ultra-low nitrogen steam generator includes an outer frame 1 71, an outer frame 2 72, an outer frame 3 73 and an outer frame 4 74 which are arranged from left to right, and the outer frame 1 71, the outer frame 2 72, the outer frame 3 73 and the outer frame 4 74 are fixedly connected to each other by bolts to form the outer shell of the steam generator, and the interiors of the outer frame 1 71, the outer frame 2 72, the outer frame 3 73 and the outer frame 4 74 are connected, and a burner 1 is fixedly installed on the upper end surface of the outer frame 1 71 by bolts, and the exhaust part of the burner 1 is connected to the interior of the outer frame 1 71.

[0018] In addition, the outer frame 1 71 , the outer frame 2 72 , the outer frame 3 73 and the outer frame 4 74 are all made of materials with good thermal insulation and sealing properties, which can ensure the stable operation of the steam generator.

[0019] The above-mentioned burner 1 is a prior art. The burner 1 mixes fuel and air (or oxygen) in a certain proportion through the precise coordination of the gas supply or oil supply system, and sends it into a combustion chamber. In the combustion chamber, the mixed fuel and air (or oxygen) undergo a combustion reaction at an appropriate temperature and pressure to produce high-temperature and high-pressure combustion flue gas, thereby releasing a large amount of heat energy. The high-temperature and high-pressure flue gas enters the outer frame 71 to heat the water, thereby generating high-temperature steam for household or industrial production.

[0020] refer to Figure 1-4A coil-type DC furnace 2 and a plurality of interconnected convection tube bundles 3 are fixedly installed in the outer frame 71. The coil-type DC furnace 2 is a section of spiral pipe, and the coil-type DC furnace 2 is located directly below the burner 1. The lower end pipe opening of the coil-type DC furnace 2 is a water inlet 21. Water is transported into the pipe of the coil-type DC furnace 2 through the water inlet 21, and then the high-temperature and high-pressure flue gas generated by the burner 1 heats the coil-type DC furnace 2, so that the water in the coil-type DC furnace 2 is heat-exchanged by the high-temperature flue gas to achieve a mixed state in which a portion of steam and water coexists.

[0021] Furthermore, since the coil-type DC furnace 2 is configured in a spiral shape, when water flows into the coil-type DC furnace 2 from the lower water inlet 21, the water flow in the coil-type DC furnace 2 can have more contact time with the high-temperature flue gas, thereby improving the heating efficiency of the water flow in the coil-type DC furnace 2.

[0022] refer to Figure 1-5 The convection tube bundle 3 is a vertical tubular structure. Several convection tube bundles 3 are fixedly connected by several connecting elbows 311. Two pipe openings communicating with the outside are reserved between the several convection tube bundles 3. A water pipe 32 is fixedly installed at one of the pipe openings. The other end of the water pipe 32 is connected to the upper end pipe opening of the coil-type DC furnace 2 through a flange.

[0023] refer to Figure 5-6 A spiral heat absorbing sheet 31 is fixedly arranged on the surface of the convection tube bundle 3. The spiral heat absorbing sheet 31 serves as an external heat absorbing component of the convection tube bundle 3 and can absorb the heat in the high-temperature flue gas in the outer frame 71. The water flow after passing through the coil-type direct current furnace 2 enters the convection tube bundle 3 through the water pipe 32. At this time, the heat absorbed from the high-temperature flue gas by the spiral heat absorbing sheet 31 heats the water flow in the convection tube bundle 3 again, thereby increasing the steam content in the steam-water mixed state in the convection tube bundle 3.

[0024] Furthermore, when the water flows through the coil-type direct current furnace 2 and enters the convection tube bundle 3, it will circulate in several convection tube bundles 3. Since the distance between the pipelines composed of several convection tube bundles 3 is relatively long, the heating time of the water flow in the convection tube bundle 3 can be effectively improved, so that the steam content in the steam-water mixed state in the convection tube bundle 3 is increased.

[0025] refer to Figure 1-4 A reheat steam pipe 4 and a drum tank body 5 are fixedly installed in the outer frame 72. The drum tank body 5 is located on the right side of the reheat steam pipe 4. One end of the reheat steam pipe 4 is connected to the drum tank body 5, and the other end is fixedly connected to the steam output pipe 42.

[0026] refer to Figure 1-4A drain tank 54 fixed to the outer surface of the outer frame 72 is arranged directly below the steam drum tank body 5, and a plurality of reheat steam pipes 53 are arranged between the drain tank 54 and the steam drum tank body 5. The two ends of the reheat steam pipe 53 are respectively communicated with the steam drum tank body 5 and the drain tank 54. A spiral heat absorbing sheet 31 is also fixedly arranged on the outer surface of the reheat steam pipe 53. The heat in the high-temperature flue gas entering the outer frame 72 is absorbed by the spiral heat absorbing sheet 31, and then the water flow in the reheat steam pipe 53 is heated again, thereby increasing the steam content in the steam-water mixed state in the reheat steam pipe 53.

[0027] refer to Figure 1 A steam-water separator 51 is fixedly provided near the top of the drum tank body 5. Through the steam-water separator 51, the steam-water mixture in the drum tank body 5 is separated and the saturated steam is separated.

[0028] refer to Figure 1 The lower end of the drain tank 54 is connected to a pipe 52, and a wastewater outlet 521 is provided at the outer end of the pipe 521. The wastewater outlet 521 is used to connect to an external collecting device. The collecting device is a prior art and does not need to be drawn or described in detail. The pipe 52 is used to discharge the water in the drain tank 54, and the drain tank 54 is used to collect the water that has not been completely evaporated in the reheat steam pipe 2 53.

[0029] refer to Figure 1-4 There are two outlets at the upper end of the convection tube bundle 3, one of which is connected to the upper end pipe mouth of the coil-type direct current furnace 2, and the outlet on the other side is fixedly connected with a water delivery pipe 2 33, the other end of the water delivery pipe 2 33 is connected to the drum tank body 5, and the pipe mouth is located below the steam-water separator 51, the steam-water mixture in the convection tube bundle 3 is sent into the drum tank body 5 through the water delivery pipe 2 33, and then enters the reheat steam pipe 2 53 below, and then the steam-water mixture is reheated by the reheat steam pipe 2 53, so that the steam content in the steam-water mixture is further improved.

[0030] Furthermore, the two outlets at the upper end of the convection tube bundle are connected to the water pipe 2 33 on the left and the water pipe 1 32 on the right. After the purified water comes out from the top of the coil-type direct current furnace 2, it enters the convection tube bundle 3 through the water pipe 1 32, and then flows through the convection tube bundle 3 and is output from the water pipe 2 33. In this process, the purified water forms a countercurrent state in the convection tube bundle, which improves the heat exchange efficiency, thereby indirectly promoting more heat transfer, and effectively increasing the steam content in the steam-water mixture coming out of the convection tube bundle 3.

[0031] refer to Figure 1-4The upper end of the reheat steam pipe 4 is provided with two pipe openings, one of which is fixedly connected to a steam input pipe 41, and the other is fixedly connected to a steam output pipe 42. One end of the steam input pipe 41 passes through the steam drum tank 5 and the steam-water separator 51, and the upper end of the steam input pipe 41 is located above the steam-water separator 51. The saturated steam passing through the steam-water separator 51 will enter the steam input pipe 41, and then enter the reheat steam pipe 4. Since most of the reheat steam pipe 4 is located in the outer frame 2 72, the high-temperature flue gas will heat the reheat steam pipe 4, thereby increasing the temperature of the saturated steam in the reheat steam pipe 4, thereby improving the use effect of the saturated steam.

[0032] refer to Figure 1-4 A plurality of vertical tubular reheat steam pipes 3 91 are fixedly installed in the outer frame 3 73 , and a spiral heat absorbing sheet 31 is also fixedly provided on the surface of the reheat steam pipe 3 91 for heating the water flow in the reheat steam pipe 3 91 .

[0033] refer to Figure 1 , 3 The lower end of the outer frame four 74 is provided with a flue gas outlet 84 communicating with the outside, and a plurality of mutually connected condensing pipes 82 are fixedly arranged inside the outer frame four 74, the outer end of a lower condensing pipe 82 is fixedly connected to a water inlet pipe 81, the outer end of an upper condensing pipe 82 is fixedly connected to a water delivery pipe three 83, the upper end of the water delivery pipe three 83 is fixedly connected to a pipe three 64 through a flange, a water storage tank 641 is fixedly installed on the upper end surface of the outer frame three 73, the water storage tank 641 is communicated with the upper end pipe openings of a plurality of reheat steam pipes three 91, and the lower end of the pipe three 64 extends into the water storage tank 641 and communicates with the water storage tank 641.

[0034] refer to Figure 3 A multi-port connecting pipe 92 is fixedly provided at the lower end of the reheat steam pipe three 91, and the multi-port connecting pipe 92 passes through the outer frame two 72 and is fixedly matched, and the multi-port connecting pipe 92 is fixedly connected to the water inlet one 21 through the pipeline four 22.

[0035] Furthermore, the treated purified water enters the condenser pipe 82 through the water inlet pipe 81, and then is transported through several condenser pipes 82, and enters the reheat steam pipe 3 91 through the pipe 3 64. Then, the high-temperature flue gas in the outer frame 3 73 preheats the purified water in the reheat steam pipe 3 91, and then enters the coil-type direct current furnace 2 through the pipe 4 22. At this time, the purified water in the coil-type DC furnace 2 will be greatly vaporized by the high-temperature flue gas, and the purified water in the coil-type DC furnace 2 will become a steam-water mixture, and then enter the convection tube bundle 3, and absorb the heat in the high-temperature flue gas through the spiral heat-absorbing plate 31 on the surface of the convection tube bundle 3, and then heat the steam-water mixture in the convection tube bundle 3 again, so that the steam content in the steam-water mixture is further increased, and then the steam-water mixture enters the steam drum tank 5, and is heated again by the reheat steam pipe 2 53, and then cooperates with the steam-water separator 51 to completely separate the saturated steam in the steam-water mixture, and the separated saturated steam is finally heated by the reheat steam pipe 1 4, so that the temperature of the discharged saturated steam is further increased, which greatly improves the use effect of the saturated steam. The above-mentioned saturated steam production process, after multiple heating treatments, can efficiently utilize the high-temperature flue gas generated by the burner 1, reduce heat loss, and improve heat energy conversion efficiency.

[0036] Furthermore, the high-temperature flue gas generated by the burner 1 will enter the outer frame 2 72 through the outer frame 1 71, then enter the outer frame 3 73, and finally enter the outer frame 4 74. The high-temperature flue gas is cooled by the condenser 82, so that the exhaust flue gas temperature can be greatly reduced.

[0037] Embodiment 2: refer to Figure 1 On the basis of the first embodiment, in order to ensure that the content of purified water in the device is sufficient, an electrode type water level gauge 6 can be fixedly installed on the outer side of the outer frame 3 73. The water level gauge 6 is a prior art and is equipped with corresponding supporting equipment.

[0038] refer to Figure 1 The outer side surface of the outer frame 74 can be fixedly mounted with a control box for controlling the device, and the water level meter 6 is connected to the control box.

[0039] refer to Figure 1 One end of the water level meter 6 is connected to the water tank 641, and the other end is connected to the pipe 52. When the water level meter 6 detects that the water level in the water tank 641 is insufficient, the water inlet can be controlled by the water level electrode to realize the automatic adjustment mode, and the water pump is used to perform flow control fine-tuning.

[0040] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect.

[0041] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0042] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A bridge-hole combustion reheat ultra-low nitrogen steam generator, characterized in that: The invention comprises an outer frame 1 (71), an outer frame 2 (72), an outer frame 3 (73) and an outer frame 4 (74) which are arranged in sequence from left to right. A burner (1) for generating high-temperature flue gas is fixedly mounted on the upper end surface of the outer frame 1 (71). The exhaust part of the burner (1) is communicated with the interior of the outer frame 1 (71). The outer frame 1 (71) is respectively fixedly mounted with a coil-type direct current furnace (2) and a plurality of interconnected convection tube bundles (3). The coil-type direct current furnace (2) is a section of spiral pipe. The convection tube bundle (3) is a vertical tubular structure, and a plurality of convection tube bundles (3) are fixedly connected via a plurality of connecting elbows (311). A reheat steam pipe (4) and a drum tank body (5) are fixedly installed in the outer frame (72). The drum tank body (5) is located on the right side of the reheat steam pipe (4). One end of the reheat steam pipe (4) is connected to the drum tank body (5), and the other end is fixedly connected to a steam discharge pipe (42). A plurality of reheat steam pipes (53) are connected below the drum tank body (5). A plurality of vertical tubular reheat steam pipes (91) are fixedly installed in the outer frame (73). The lower end of the outer frame four (74) is provided with a smoke outlet (84) communicating with the outside, and a plurality of condensation pipes (82) communicating with each other are fixedly arranged inside the outer frame four (74).

2. A bridge-hole combustion reheat ultra-low nitrogen steam generator according to claim 1, characterized in that: The surfaces of the convection tube bundle (3), the second reheat steam tube (53) and the third reheat steam tube (91) are all fixedly provided with spiral heat absorbing sheets (31) for absorbing the heat of high-temperature flue gas.

3. The bridge-hole combustion reheat ultra-low nitrogen steam generator according to claim 1 is characterized in that: The outer frame 1 (71), the outer frame 2 (72), the outer frame 3 (73) and the outer frame 4 (74) are all fixedly connected to each other by bolts, and the interiors of the outer frame 1 (71), the outer frame 2 (72), the outer frame 3 (73) and the outer frame 4 (74) are all connected.

4. The bridge-hole combustion reheat ultra-low nitrogen steam generator according to claim 1 is characterized in that: The outer end of the lower condenser (82) is fixedly connected to a water inlet pipe (81), and the outer end of the upper condenser (82) is fixedly connected to a water supply pipe three (83). The upper end of the water supply pipe three (83) is fixedly connected to a pipe three (64) via a flange. A water storage tank (641) is fixedly installed on the upper end surface of the outer frame three (73). The water storage tank (641) is connected to the upper end pipe openings of a plurality of reheat steam pipes three (91), and the lower end of the pipe three (64) extends into the water storage tank (641) and communicates with the water storage tank (641).

5. The bridge-hole combustion reheat ultra-low nitrogen steam generator according to claim 1 is characterized in that: A multi-port connecting pipe (92) is fixedly provided at the lower end of the reheat steam pipe three (91), and the multi-port connecting pipe (92) penetrates the outer frame two (72) and is fixedly fitted therewith. A water inlet one (21) is provided at the lower end of the coil-type direct current furnace (2), and a pipeline four (22) is fixedly connected between the multi-port connecting pipe (92) and the water inlet one (21).

6. The bridge-hole combustion reheat ultra-low nitrogen steam generator according to claim 1, characterized in that: A number of the convection tube bundles (3) are provided with two pipe openings communicating with the outside, one of the pipe openings being fixedly provided with a water delivery pipe (32), the other end of the water delivery pipe (32) being connected to the upper pipe opening of the coil-type direct current furnace (2) via a flange, the outlet on the other side being fixedly connected with a water delivery pipe (33), the other end of the water delivery pipe (33) being communicated with the steam drum tank body (5).

7. The bridge-hole combustion reheat ultra-low nitrogen steam generator according to claim 1 is characterized in that: A drainage tank (54) fixed to the outer surface of the second outer frame (72) is arranged directly below the steam drum tank body (5); the lower end of the drainage tank (54) is connected to the first pipeline (52); the two ends of the second reheat steam pipe (53) are respectively connected to the steam drum tank body (5) and the drainage tank (54); a steam-water separator (51) is fixedly arranged near the upper part of the steam drum tank body (5).

8. The bridge-hole combustion reheat ultra-low nitrogen steam generator according to claim 7 is characterized in that: The upper end of the reheat steam pipe 1 (4) is provided with two pipe openings, one of which is fixedly connected to a steam input pipe (41), and the other is fixedly connected to a steam output pipe (42). One end of the steam input pipe (41) passes through the steam drum tank (5) and the steam-water separator (51), and the upper end of the steam input pipe (41) is located above the steam-water separator (51).

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