CN112268270B - Skid-mounted water pipe type low-nitrogen gas steam boiler - Google Patents

Abstract

The invention belongs to the technical field of boiler equipment, and particularly relates to a skid-mounted water pipe type low-nitrogen gas steam boiler which comprises a shell and a burner, wherein a boiler barrel, a water-cooling upper header and a water-cooling lower header are arranged in the shell; a left membrane type water-cooled wall and a right membrane type water-cooled wall are connected between the water-cooled upper header and the water-cooled lower header; the region between the left membrane type water-cooled wall and the right membrane type water-cooled wall is a hearth; the left membrane type water-cooling wall and the right membrane type water-cooling wall are formed by welding a plurality of water-cooling wall tubes and a plurality of fins side by side, and the fins are connected with two adjacent water-cooling wall tubes; the back fire side of the fins is provided with convex blocks, the convex blocks of different fins are arranged in a plurality of rows, and the convex blocks in the same row are connected through a first reinforcing strip. The steam separation height is high, and meanwhile, the membrane water-cooled wall is not easy to deform when being heated, and the integral stability is high; compared with a boiler with the same capacity, the water volume is small, and the steam production is fast; compared with the boiler with the same volume, the boiler has large volume of the hearth, and is beneficial to realizing low-nitrogen combustion; and an integral skid-mounted structure is adopted, so that the transportation and the installation are more convenient.

Description

A skid-mounted water-tube low-nitrogen gas-fired steam boiler

technical field

The invention belongs to the technical field of boiler equipment, in particular to a skid-mounted water tube low-nitrogen gas-fired steam boiler.

Background technique

Boilers are heat supply equipment, and electric power, industry and civil industries all need to supply heat through boilers. In order to provide heat, boilers generally use natural gas fuel or gas fuel to heat the organic medium to reach the temperature required by industry and life. The organic medium output by the boiler can be high temperature water or steam. The steam produced by the steam boiler in the prior art has a relatively low separation height and a large amount of water in the steam, resulting in poor steam quality.

The patent with the publication number of CN 111156486A discloses a water tube waste heat steam boiler, which includes an upper drum, and both sides of the upper drum are fixedly sleeved with convection tube bundles, and the inside of the convection tube bundles on both sides are respectively equipped with left membrane type wall and the right membrane wall, the end of the convection tube bundle far away from the upper drum is fixedly connected with the lower right header and the lower left header respectively, and the waste heat flue gas is introduced into the inside of the upper drum, and the convection flow is directed from the water inlet Water is injected into the tube bundle, and the waste heat flue gas transfers heat to the water in the convection tube bundle, and the water inside the convection tube bundle absorbs the heat of the flue gas to form water vapor. discharge. Although a water tube waste heat steam boiler can fully recover the heat in the waste heat flue gas, the separation height between the convection tube bundle and the upper drum is low, and the steam flowing out of the upper drum carries a large amount of water. In addition, the water-tube waste heat steam boiler with the publication number CN 111156486A also has the problems that the membrane water-cooled wall is easily deformed by heat and the overall structure is unstable.

Contents of the invention

The purpose of the present invention is to solve the problems in the prior art that the steam separation height generated by the steam boiler water is low, the membrane water wall is easily deformed when heated, and the overall structure is unstable, and proposes a skid-mounted water tube low-nitrogen gas-fired steam boiler .

To achieve the above technical purpose, the present invention adopts the following technical solutions:

A skid-mounted water-tube low-nitrogen gas-fired steam boiler includes a shell and a burner. The shell is provided with a drum, a water-cooled upper header, and a water-cooled lower header; the drum and the water-cooled upper header are connected by a The steam pipe, the water-cooled upper header and the water-cooled lower header are connected with the left membrane water wall and the right membrane water wall; the area between the left membrane water wall and the right membrane water wall is the furnace, and the combustion of the burner The end is located at the inlet of the furnace; there are several water-cooled wall tubes arranged at intervals between the water-cooled upper header and the water-cooled lower header, and the water-cooled wall tubes are aligned side by side with the right membrane-type water-cooled wall; the gap between adjacent water-cooled wall tubes is The flue gas outlet in the furnace; the left membrane water wall and the right membrane water wall are welded by multiple water wall tubes and multiple fins side by side, and the fins connect two adjacent water wall tubes; Protrusions are provided, and the protrusions of different fins are arranged in several rows, and the protrusions in the same row are connected through the first reinforcing bar.

Further, the protrusions of the same fin are arranged along the length direction of the fin, and the protrusions of the same fin are connected through the second reinforcing strip.

Further, the housing is also provided with a first convection upper header, a first convection lower header, a second convection upper header, and a second convection lower header; wherein, the first convection upper header, the second convection The upper headers are parallel to the water-cooled upper header and located on the same level; the first convection lower header and the second convection lower header are parallel to the water-cooled lower header and located on the same horizontal plane; the first convection upper header and the drum Steam pipes are connected between the second convection upper header and the drum, the first convection upper header and the first convection lower header are connected with the first convection tube group, the second convection upper header and the second convection upper header A second convection tube group is connected between the two convection down headers; after the smoke in the furnace flows out, it flows through the first convection tube group and the second convection tube group successively.

Further, the first convection tube group is divided into a low-temperature zone and a high-temperature zone, and the flue gas flows from the high-temperature zone into the low-temperature zone; the first convection tube group in the low-temperature zone and the first convection tube group in the high-temperature zone both include the first internal convection tube and The first external convection tube; both sides of the first convection lower header are provided with a first internal convection tube and a first external convection tube, and the first internal convection tube and the first convection tube located on the same side of the first convection lower header The outer convection pipes are staggered; the first inner convection pipes are arranged on both sides of the first convection lower header; the first outer convection pipes are arranged on both sides of the first convection lower header.

Further, spiral fins are provided on the outside of the first inner convection tube and the first outer convection tube in the low temperature zone; the flue gas in the low temperature zone flows horizontally along the length direction of the first convection lower header as a whole, and scours the first convection lower header horizontally. An inner convection tube and spiral fins of the first outer convection tube.

Further, the second convection pipe group includes a second inner convection pipe and a second outer convection pipe, and both sides of the second convection lower header are provided with second inner convection pipes and second outer convection pipes; The second inner convection pipe and the second outer convection pipe on the same side of the header are staggered; the second inner convection pipes on both sides of the second convection lower header are staggered.

Further, a smoke partition is provided between the adjacent second external convection tubes on the same side of the second convection lower header, and the smoke partitions on the same side are connected with the second external convection tube to form a partition wall; The area between the partition walls on both sides of the second convection down-flow header constitutes the flue gas channel; the outer side of the second inner convection tube is provided with spiral fins; the flue gas enters the flue gas channel from the low temperature area of the first convection tube bundle, and the overall It flows horizontally along the length direction of the second convection lower header, and scours the spiral fins of the second inner convection pipe laterally.

Further, the outlet of the flue gas passage is connected to the condensing economizer; a chimney is arranged on the top of the housing, and the condensing economizer is connected to the chimney; a flue gas return pipe is arranged between the chimney and the burner.

Further, the two ends of the water-cooled lower header are connected to the two ends of the first convection lower header respectively through the communication pipes, and the two ends of the first convection lower header are respectively connected to the two ends of the second convection lower header through the communication pipes. corresponding connection.

Further, a communication pipe between the water-cooled lower header and the first convective lower header is provided with a water inlet; the drum is provided with a steam outlet, and the steam outlet is provided with a steam-water separator.

Further, the water-tube low-nitrogen gas-fired steam boiler is skid-mounted as a whole.

Compared with the prior art, the beneficial technical effect of the present invention is:

(1) The steam separation height of the present invention is high, the steam flowing out of the drum has less water content, and the steam quality is good; compared with boilers with the same capacity, the water volume is small, and the steam production is fast; at the same time, the membrane water wall is not easy to deform when heated, and the overall stability is high. ;

(2) The furnace adopts membrane-type water-cooled wall, which has good sealing performance, large furnace volume, low furnace temperature level, and reduces the generation and emission of nitrogen oxides; compared with boilers with the same capacity, the furnace has a large volume, which is conducive to realizing low-nitrogen combustion; the drum is not Directly radiated by high-temperature flames, there is no problem that the tube plate in front of the steam boiler back-combustion chamber is prone to cracks at the tube ends;

(3) The flue gas laterally scours the first inner convection tube with spiral fins in the first convection tube bundle, the first outer convection tube, and the second inner convection tube with spiral fins in the second convection tube bundle, with a compact structure, The heating area is sufficient to maximize the recovery of flue gas heat and generate more water vapor;

(4) The present invention adopts an integral skid-mounted structure, which is more convenient for transportation and installation.

Description of drawings

Fig. 1 is a front perspective structure diagram of a skid-mounted water tube type low-nitrogen gas-fired steam boiler shell in this embodiment;

Fig. 2 is a side perspective structure diagram of a skid-mounted water tube type low-nitrogen gas-fired steam boiler shell in this embodiment;

Fig. 3 is a top perspective structure diagram of a skid-mounted water tube type low-nitrogen gas-fired steam boiler shell in this embodiment;

Fig. 4 is a front internal structure diagram of a skid-mounted water tube type low-nitrogen gas-fired steam boiler shell in this embodiment;

Fig. 5 is a side internal structure diagram of a skid-mounted water tube type low-nitrogen gas-fired steam boiler shell in this embodiment;

Fig. 6 is A-A sectional view in Fig. 5;

Fig. 7 is a partial enlarged structural diagram of the connection between the bump and the first reinforcing bar in this embodiment;

FIG. 8 is a partial enlarged structural view of the connection between the bump and the second reinforcing bar in this embodiment.

In the figure, 1 shell, 2 burner, 3 drum, 4 furnace, 5 water-cooled upper header, 6 water-cooled lower header, 7 first convection upper header, 8 first convection lower header, 9 second convection Upper header, 10 second convection lower header, 11 left membrane water wall, 12 right membrane water wall, 13 bump, 14 first reinforcement bar, 15 second reinforcement bar, 16 first internal convection pipe, 17 The first external convection pipe, 18 the second internal convection pipe, 19 the second external convection pipe, 20 spiral fins, 21 fins, 22 flue gas return pipe, 23 water inlet, 24 steam outlet, 25 chimney, 26 aluminum silicate fiberboard.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

As shown in Figures 1-6, this embodiment is a skid-mounted water-tube low-nitrogen gas-fired steam boiler, including a shell 1 and a burner 2 . A drum 3 , a water-cooled upper header 5 and a water-cooled lower header 6 are arranged in the shell 1 from top to bottom, and a steam pipe is connected between the drum 3 and the water-cooled upper header 5 . Between the water-cooled upper header 5 and the water-cooled lower header 6, a membrane-type water-cooled wall arranged vertically in a "D" shape is arranged. The membrane water cooling wall is specifically a left membrane water cooling wall 11 and a right membrane water cooling wall 12 connected between the water cooling upper header 5 and the water cooling lower header 6 . The area between the left membrane water wall 11 and the right membrane water wall 12 is the furnace 4 , and the combustion end of the burner 2 is located at the inlet of the furnace 4 . Several water-cooled wall tubes arranged at intervals are also connected between the water-cooled upper header 5 and the water-cooled lower header 6, and the water-cooled wall tubes are aligned with the right membrane-type water-cooled wall 12 side by side. The gap between adjacent water wall tubes is the flue gas outlet in the furnace 4 . The fuel burns in the furnace 4 to release heat. The aqueous solution in the water-cooled lower header 6 absorbs the heat released by the fuel during the process of reaching the water-cooled upper header 5 through the left membrane water wall 11 or the right membrane water wall 12, and the water-cooled upper header 5 is a mixture of steam and water. Afterwards, when the steam-water mixture enters the drum 3 through the steam pipe, due to the increase in height, the steam-water mixture separates, causing more water vapor to enter the drum 3, while the liquid aqueous solution returns to the drum under the action of gravity. Water cooling in the upper header 5. Therefore, the water circulation of this embodiment adopts the water-cooled lower header 6, the water-cooled upper header 5 and the drum 3, the steam separation height is high, the steam flowing out of the drum 3 has less water, and the steam quality is good. Compared with boilers with the same capacity, this implementation has smaller water volume and faster steam production. At the same time, the 4 walls of the furnace adopt membrane-type water-cooled walls, which increase the radiation heating area of the furnace, improve the boiler output and thermal efficiency, improve the sealing performance of the furnace, simplify the heat preservation structure, reduce the weight of the boiler, improve the rigidity of the furnace flue, and improve the anti-knock ability of the boiler furnace. The micro-positive pressure combustion of the water-cooled wall reduces the air leakage coefficient. This embodiment adopts a larger furnace size, increases the radiation heating area and reduces the furnace temperature, which is beneficial to reduce the generation and emission of thermal nitrogen oxides. Compared with boilers with the same capacity, the furnace 4 in this embodiment has a larger volume, which is beneficial to realize low-nitrogen combustion. In addition, the fuel is burned in the furnace 4, and the drum 3 is not directly radiated by the high-temperature flame, so there is no problem that the tube plate of the steam boiler before the combustion chamber is prone to cracks at the tube end.

As shown in Figure 7 and Figure 8, the left membrane water wall 11 and the right membrane water wall 12 are welded side by side by multiple water wall tubes and multiple fins 21, and the fins 21 connect two adjacent water wall tubes . Protrusions 13 are provided on the back side of the fins 21 , the protrusions 13 of different fins 21 are arranged in several rows, and the protrusions 13 in the same row are connected by the first reinforcing strip 14 . During the combustion process of the fuel in the furnace 4, the temperature of the fins 21 is higher than that of the water-cooled wall tube, so the probability of thermal deformation is greater. As a result of thermal deformation of the fins 21, cracks will appear, resulting in damage to the entire membrane water cooling wall. In this embodiment, the structural strength of the fin 21 can be enhanced by welding the bump 13 on the surface of the fin 21 on the side not exposed to fire. At the same time, because the bump 13 is small in size and occupies less area, the installation process of the bump 13 and the fin 21 is simple. During the installation process, it is only necessary to weld the bump 13 and the fin 21 at a certain position of the fin 21 . Each first reinforcing bar 14 on the back fire side of the left membrane water cooling wall 11 is connected to all the fins 21 of the left membrane water cooling wall 11, so that all the fins 21 of the left membrane water cooling wall 11 are combined into a whole to ensure that the left The structural stability of the membrane water wall 11. Each first reinforcing strip 14 on the back fire side of the right membrane water cooling wall 12 is connected to all the fins 21 of the right membrane water cooling wall 12, so that all the fins 21 of the right membrane water cooling wall 12 are combined into a whole to ensure that the right The structural stability of the membrane water wall 12. The protrusions 13 of the same fin 21 are arranged along the length direction of the fin 21 , and the protrusions 13 of the same fin 21 are connected by the second reinforcing strip 15 . Specifically, the protruding block 13 may be provided with a through hole, and the second reinforcing bar 15 passes through the through hole to connect several protruding blocks 13 . The unfired side of the left membrane water cooling wall 11 and the unfired side of the right membrane water cooling wall 12 are both provided with a network structure composed of first reinforcing strips 14 and second reinforcing strips 15 to enhance the structural strength of the fins 21. It can also enhance the overall stability of the membrane water wall.

As shown in FIG. 5 and FIG. 6 , a first convection upper header 7 , a first convection lower header 8 , a second convection upper header 9 and a second convection lower header 10 are also provided in the housing 1 . Among them, the first convection upper header 7 and the second convection upper header 9 are parallel to the water-cooled upper header 5 and located on the same horizontal plane, and the first convection lower header 8 and the second convection lower header 10 are all connected to the water-cooled lower header. The boxes 6 are parallel and located on the same level. Steam pipes are connected between the first convection upper header 7 and the drum 3, between the second convection upper header 9 and the drum 3, and between the first convection upper header 7 and the first convection lower header 8 A first convection tube group is connected, and a second convection tube group is connected between the second convection upper header 9 and the second convection lower header 10 . The water-cooled upper header 5, the water-cooled lower header 6, and the membrane-type water-cooled wall between the water-cooled upper header 5 and the water-cooled lower header 6 are the first module as a whole. The first convection upper header 7, the first convection lower header 8, and the first convection tube group between the first convection upper header 7 and the first convection lower header 8 are the second module as a whole. The second convection upper header 9 , the second convection lower header 10 , and the second convection tube bundle group between the second convection upper header 9 and the second convection lower header 10 are the third module as a whole. Drum 3 is the fourth module. In this embodiment, module 1, module 2, module 3, and module 4 are assembled in a modular manner to facilitate manufacturing, maintenance, replacement, and capacity expansion. Each steam pipe is externally welded to its corresponding water-cooled upper header 5 , first convection upper header 7 , and second convection upper header 9 . This embodiment adopts a modular assembly structure, which creates favorable conditions for the use of external welding, and can greatly reduce the overall size of the boiler and steel consumption.

After the flue gas in the furnace 4 flows out, it flows through the first convection tube group and the second convection tube group successively. The aqueous solution in the first convection lower header 8 absorbs the heat in the flue gas during the process of reaching the first convection upper header 7 through the first convection tube group, and the first convection upper header 7 is a mixture of steam and water. Afterwards, when the steam-water mixture enters the drum 3 through the steam pipe, due to the increase in height, the steam-water mixture separates, causing more water vapor to enter the drum 3, while the liquid aqueous solution returns to the first drum under the action of gravity. A pair of upper headers 7. The changing state of the aqueous solution of the second convective lower header 10 is the same as the aqueous solution of the first convective lower header 8 . Therefore, the water cycle in this embodiment can maximize the recovery of heat in the exhausted flue gas by using the first convection upper header 7, the first convection lower header 8, the second convection upper header 9, and the second convection lower header 10. And improve the total amount and quality of steam generation.

The first convection tube group is divided into a low-temperature zone and a high-temperature zone, and the flue gas flows from the high-temperature zone into the low-temperature zone. Both the first convection tube group in the low temperature zone and the first convection tube group in the high temperature zone include a first inner convection tube 16 and a first outer convection tube 17 . Both sides of the first convection lower header 8 are provided with a first inner convection pipe 16 and a first outer convection pipe 17, and the first inner convection pipe 16 and the first outer convection pipe located on the same side of the first convection lower header 8 17 Misplacement arrangement. The first internal convection pipes 16 located on both sides of the first convection lower header 8 are arranged in a staggered position. The first external convection pipes 17 located on both sides of the first convection lower header 8 are arranged in a staggered position. The first outer convection pipe 17 , the first inner convection pipe 16 are connected to the first convection upper header 7 in the same manner as the first convection lower header 8 . The outer side of the first inner convection tube 16 and the outer side of the first outer convection tube 17 in the low temperature zone are provided with spiral fins 20, specifically, the spiral fins 20 are sleeved on the outer wall of the first inner convection tube 16 and connected to the first inner convection tube 17. The outer wall of the convection tube 16 is welded, and the spiral fin 20 is sleeved on the outer wall of the first outer convection tube 17 and welded to the outer wall of the first outer convection tube 17 . Both the first inner convection tube 16 and the first outer convection tube 17 are arc-shaped, and the arc radius of the first outer convection tube 17 is larger than the arc radius of the first inner convection tube 16 . The pipes located in the middle section of the first inner convection pipe 16 and the pipes located in the middle section of the first outer convection pipe 17 are both vertical pipes, and the spiral fins 20 are sleeved on the vertical parts. The high temperature zone is close to the flue gas outlet of the furnace 4, and the low temperature zone extends away from the flue gas outlet of the furnace 4. The flue gas in the low temperature area flows horizontally along the length direction of the first convection lower header 8 as a whole, and scours the spiral fins 20 of the first inner convection pipe 16 and the first outer convection pipe 17 laterally. The spiral fins 20 can increase the flue gas During the circulation process, the contact area with the first inner convection pipe 16 and the first outer convection pipe 17 enhances the heat exchange effect, recovers the heat of the flue gas to the maximum extent, and generates more water vapor. In addition, the flue gas scours the spiral fins 20 horizontally to ensure the strongest heat exchange effect. Therefore, the convection tube bundle in this embodiment adopts spiral finned tubes, which has a compact structure, expands the heating area on the flue gas side, reduces the exhaust gas temperature, improves the thermal efficiency of the boiler, and further reduces the overall size of the boiler.

The second convection tube group includes a second inner convection tube 18 and a second outer convection tube 19 , and both sides of the second convection upper header 98 are provided with the second inner convection tube 18 and the second outer convection tube 19 . The second inner convection pipe 18 and the second outer convection pipe 19 located on the same side of the second convection lower header 10 are arranged in a staggered position. The second internal convection pipes 18 located on both sides of the second convection lower header 10 are arranged in a staggered position. The second inner convection pipe 18 , the second outer convection pipe 19 are connected to the second convection upper header 9 in the same manner as the second convection lower header 10 . A smoke partition is provided between adjacent second external convection pipes 19 on the same side of the second convection lower header 10 , and the smoke partitions on the same side are connected with the second external convection pipes 19 to form a partition wall. The area between the partition walls on both sides of the second convective downflow header 10 constitutes a flue gas channel. The outer side of the second inner convection tube 18 is provided with spiral fins 20 , specifically, the spiral fins 20 are sleeved on the outer wall of the second inner convection tube 18 and welded to the outer wall of the second inner convection tube 18 . Both the second inner convection tube 18 and the second outer convection tube 19 are arc-shaped, and the arc radius of the second outer convection tube 19 is larger than the arc radius of the second inner convection tube 18 . The pipeline located in the middle section of the second inner convection pipe 18 and the pipeline located in the middle section of the second outer convection pipe 19 are vertical pipes. The spiral fins 20 are sleeved on the vertical portion of the second inner convection tube 18 .

The flue gas partition is provided with a flue gas inlet, from which the flue gas enters the flue gas channel, and the flue gas inlet is close to the end of the flue gas circulation in the low-temperature zone of the first convection tube group. The flue gas enters the flue gas channel from the low temperature area of the first convection tube group through the flue gas inlet, and flows horizontally along the length direction of the second convection lower header 10 as a whole, and scours the spiral fins 20 of the second inner convection tube 18 laterally. The spiral fins 20 can increase the contact area between the flue gas and the second internal convection pipe 18 during circulation, enhance the heat exchange effect, recover the heat of the flue gas to the maximum extent, and generate more water vapor. In addition, the flue gas scours the spiral fins 20 horizontally to ensure the strongest heat exchange effect.

The overall horizontal flow direction of the flue gas is deflected by 90° from circulating in the furnace 4 to flowing out from the flue gas outlet of the furnace 4 . After the flue gas enters the first convection tube group from the flue gas outlet of the furnace 4, the overall horizontal flow direction of the flue gas is deflected by 90°. After the flue gas enters the flue gas channel of the second convection tube group from the first convection tube group, the overall horizontal flow direction of the flue gas is deflected by 180°. Constantly adjust the flue gas flow direction to facilitate the settlement of impurities contained in the flue gas, while increasing the flue gas circulation length and improving the heat exchange efficiency of the boiler. The outlet of the flue gas channel is connected with the condensing economizer, and the temperature of the flue gas is reduced through the condensing economizer. The exhaust gas temperature is lower than 60°C. For the low calorific value, the thermal efficiency can reach 101%, reducing the harmful substances in the flue gas. emission. The condensing economizer adopts the circulation pump to increase the water volume and continuously circulate, increase the water speed in the pipe, increase the heat transfer coefficient, reduce the exhaust gas temperature, and improve the thermal efficiency.

A chimney 25 is arranged on the top of the housing 1 , the condensing economizer communicates with the chimney 25 , and a flue gas return pipe 22 is arranged between the chimney 25 and the burner 2 . Part of the flue gas whose temperature is lowered by the condensing economizer is discharged, and the other part can be returned to the burner 2 to mix with the gas, and through the backflow of the flue gas, the combustion temperature, oxygen concentration and partial pressure of the furnace are reduced, reducing the generation of thermal NOx. meet low emission requirements. When the flue gas is backflowing, choose an economical and reasonable flue gas flow rate to reduce resistance and reduce the operating power consumption of the blower or burner fan. In order to further realize the effect of low nitrogen emission, the burner 2 of this embodiment can adopt a low nitrogen burner. According to the requirements of low nitrogen emission, the imported brand-name low-nitrogen burner is reasonably selected, combined with the large-size furnace, to meet the needs of flame diameter and length, and to further optimize the matching between the burner and the furnace size.

The two ends of the water-cooled lower header 6 are respectively connected to the two ends of the first convection lower header 8 through the communication pipes, and the two ends of the first convection lower header 8 are respectively connected to the two ends of the second convection lower header 10 through the communication pipes. corresponding to the connection. In this embodiment, the water-cooled upper header 5, the water-cooled lower header 6, the first convective upper header 7, the first convective lower header 8, the second convective upper header 9, and the second convective lower header 10 have the same length. And both ends are aligned. A connecting pipe between the water-cooled lower header 6 and the first convective lower header 8 is provided with a water inlet 23 , and the drum 3 is provided with a steam outlet 24 . The circulating water medium in the boiler enters from the water inlet 23 of the communication pipe, and the generated steam flows out from the steam outlet 24 . In order to further reduce the amount of water carried by the steam, the steam outlet 24 is provided with a steam-water separator. The boiler drum 3 has a small volume, so the boiler water volume is small, and when the heating block is activated, steam can be released in a few minutes, and the heat dissipation loss is small after the furnace is shut down at night. The insulation material on the wall of the casing 1 is aluminum silicate fiberboard 26, which is laminated with staggered joints to reduce heat loss and heat storage in the furnace wall. The thermal inertia is good and the temperature rises quickly after starting. This embodiment adopts an advanced automatic control system, specifically the combination of PLC and touch screen, which is simple and reliable in operation, realizes automatic ignition, automatic load adjustment, and automatic intelligent control of start-stop leak detection. In this embodiment, the water-tube low-nitrogen gas-fired steam boiler adopts a skid-mounted type as a whole, and the relevant economizers, feed water pumps, pipelines, valves, instruments, and control devices are all installed in place and then shipped out of the factory. The transportation and installation are more convenient, and the structure is compact. , Easy installation and use, beautiful appearance, saving infrastructure investment, saving installation costs and so on.

The embodiments of the present invention have been described in detail above. For those of ordinary skill in the art, according to the ideas provided by the present invention, there will be changes in the specific implementation, and these changes should also be regarded as the scope of protection of the present invention. .

Claims (9)

1. A skid-mounted water tube type low-nitrogen gas-fired steam boiler, comprising a shell and a burner, characterized in that: The shell is equipped with a drum, a water-cooled upper header and a water-cooled lower header; a steam pipe is connected between the drum and the water-cooled upper header, and a left membrane water-cooled wall and right membrane water wall; The area between the left membrane water cooling wall and the right membrane water cooling wall is the furnace, and the combustion end of the burner is located at the furnace inlet; there are several water cooling wall tubes arranged at intervals between the water cooling upper header and the water cooling lower header. The water wall tubes are aligned side by side with the right membrane water wall; the gap between adjacent water wall tubes is the flue gas outlet in the furnace; The left membrane water wall and the right membrane water wall are welded by multiple water wall tubes and multiple fins side by side, and the fins connect two adjacent water wall tubes; The bumps of the sheet are arranged in several rows, and the bumps in the same row are connected by the first reinforcing bar; The housing is also provided with a first convection upper header, a first convection lower header, a second convection upper header and a second convection lower header; wherein, the first convection upper header, the second convection upper header Both are parallel to the water-cooled upper header and located on the same horizontal plane, and the first convection lower header and the second convective lower header are parallel to the water-cooled lower header and located on the same horizontal plane; Steam pipes are connected between the first convection upper header and the drum, between the second convection upper header and the drum, and the first convection pipe is connected between the first convection upper header and the first convection lower header A second convection tube group is connected between the second convection upper header and the second convection lower header; after the flue gas in the furnace flows out, it flows through the first convection tube group and the second convection tube group; The water-cooled upper header, the water-cooled lower header, the membrane water wall between the water-cooled upper header and the water-cooled lower header are the first module; the first convection upper header, the first convection lower The first convection pipe group between the header and the first convection lower header is the second module as a whole; the second convection upper header, the second convection lower header, the second convection upper header and the second convection lower header The second convection tube bundle between them is the third module as a whole; the drum is the fourth module; The first convection tube group is divided into a low temperature zone and a high temperature zone, and the flue gas flows into the low temperature zone from the high temperature zone; both the first convection tube group in the low temperature zone and the first convection tube group in the high temperature zone include a first inner convection tube, Convection tube; Both the outer side of the first inner convection tube and the outer side of the first outer convection tube in the low temperature zone are provided with spiral fins, specifically, the spiral fins are sleeved on the outer wall of the first inner convection tube and welded to the outer wall of the first inner convection tube , the helical fins are sleeved on the outer wall of the first outer convection tube and welded to the outer wall of the first outer convection tube; the first inner convection tube and the first outer convection tube are both arc-shaped structures, and the arc shape The radius is greater than the radius of the arc of the first inner convection tube; the pipes located in the middle section of the first inner convection pipe and the pipes located in the middle section of the first outer convection pipe are vertical pipes, and the spiral fins are sleeved on the vertical parts. 2. The skid-mounted water-tube low-nitrogen gas-fired steam boiler according to claim 1, characterized in that: The protruding blocks of the same fin are arranged along the length direction of the fin, and the protruding blocks of the same fin are connected through the second reinforcing bar. 3. The skid-mounted water-tube low-nitrogen gas-fired steam boiler according to claim 1, characterized in that: The first convection tube group is divided into a low-temperature zone and a high-temperature zone, and the flue gas flows into the low-temperature zone from the high-temperature zone; Convection tube; Both sides of the first convection lower header are provided with a first inner convection pipe and a first outer convection pipe, and the first inner convection pipe and the first outer convection pipe located on the same side of the first convection lower header are arranged in a staggered position; The first inner convection tubes located on both sides of the first convection lower header are arranged in a staggered position; the first outer convection tubes located on both sides of the first convection lower header are arranged in a staggered position. 4. The skid-mounted water-tube low-nitrogen gas-fired steam boiler according to claim 3, characterized in that: The outer sides of the first inner convection tube and the first outer convection tube in the low temperature zone are provided with spiral fins; the flue gas in the low temperature zone flows horizontally along the length direction of the first convection lower header as a whole, and scours the first inner convection tube horizontally. tube with the helical fins of the first outer convection tube. 5. The skid-mounted water-tube low-nitrogen gas-fired steam boiler according to claim 1, characterized in that: The second convection tube group includes a second inner convection tube and a second outer convection tube, and both sides of the second convection lower header are provided with a second inner convection tube and a second outer convection tube; The second inner convection pipe and the second outer convection pipe on the same side of the tank are staggered; the second inner convection pipes located on both sides of the second convection lower header are staggered. 6. The skid-mounted water-tube low-nitrogen gas-fired steam boiler according to claim 5, characterized in that: A smoke partition is arranged between the adjacent second external convection pipes on the same side of the second convection lower header, and the smoke partitions on the same side are connected with the second external convection pipe to form a partition wall; the second convection lower The area between the partition walls on both sides of the header forms the flue gas channel; the outer side of the second inner convection tube is provided with spiral fins; the flue gas enters the flue gas channel from the low temperature area of the first convection tube bundle, The length direction of the convection lower header flows horizontally and scours the spiral fins of the second inner convection pipe laterally. 7. The skid-mounted water-tube low-nitrogen gas-fired steam boiler according to claim 6, characterized in that: the outlet of the flue gas channel communicates with the condensing economizer; the top of the shell is provided with a chimney, and the condensing economizer communicates with the chimney ; There is a flue gas return pipe between the chimney and the burner. 8. The skid-mounted water-tube low-nitrogen gas-fired steam boiler according to claim 1, characterized in that: the two ends of the water-cooled lower header are respectively connected to the two ends of the first convection lower header through connecting pipes, and the first The two ends of the convection lower header are correspondingly connected with the two ends of the second convection lower header respectively through communication pipes. 9. The skid-mounted water-tube low-nitrogen gas-fired steam boiler according to claim 8, characterized in that: a connecting pipe between the water-cooled lower header and the first convection lower header is provided with a water inlet; There is a steam outlet, and the steam outlet is provided with a steam-water separator.

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