A heat transfer enhanced vertical pipe water-cooled gas steam generator

Abstract

The invention discloses an enhanced heat transfer vertical tube water-cooled gas steam generator, comprising an upper header and a lower header; a tube-type membrane water-cooled wall is arranged between the upper header and the lower header, a gas inlet and a smoke outlet are arranged on the tube-type membrane water-cooled wall, the gas inlet is connected to an air intake bin, a water-cooled plane burner is arranged in the air intake bin, the water-cooled plane burner comprises a water-cooled fire row tube bundle which is surrounded by the tube-type membrane water-cooled wall to form a combustion furnace cavity, an enhanced convection heat exchange tube bundle furnace is arranged in the combustion furnace cavity, the space occupied by the enhanced convection heat exchange tube bundle forms a heat exchange chamber, and the space between the enhanced convection heat exchange tube bundle furnace and the water-cooled fire row tube bundle forms a combustion chamber; the smoke outlet is connected to a tail normal pressure economizer, and the tail normal pressure economizer is connected to a smoke collecting box; the water inlet of the lower header and the water outlet of the tail normal pressure economizer are connected through a pipeline and a water pump. The invention has high heat exchange efficiency, low combustion temperature and smoke exhaust temperature, can achieve low-cost and low-nitrogen emissions, and has a long service life.

Description

Technical Field

[0001] The invention relates to a steam generator, in particular to an enhanced heat transfer vertical tube type water-cooled gas steam generator. Background Art

[0002] At present, the gas steam generators on the market all adopt the method of separating the burner from the main body. The main body is produced by the manufacturer, and the burner is purchased from outside. The main structure of the steam generator generally adopts the structure of coils, serpentines or vertical smoke pipes. The principle is that the flame ejected by the gun burner, surface burner or post-premix burner heats the coil, serpentine or smoke pipe of the boiler, so that the water in contact with it forms steam; the water in the coil or serpentine continuously flows from the lower low-temperature area to the upper high-temperature area, and finally forms steam and sprays out. This heating method causes the water in the coil or serpentine to become steam at the end of the coil or serpentine, causing the tube to burn dry, and it is easy to deform, burn, and scale; the smoke pipe type is difficult to achieve the required output in a limited volume without dry burning.

[0003] In addition, when natural gas is burned, nitrogen in the air reacts with oxygen at high temperature to produce a large amount of nitrogen oxides. When the temperature is below 1050℃, the amount of nitrogen oxides generated is very small, and as the temperature rises, when it is greater than 1200℃, the amount of nitrogen oxides generated gradually increases. The higher the combustion temperature, the geometric increase in the rate of nitrogen oxide generation. At present, various steam generators on the market use gun-type diffusion burners (non-low nitrogen combustion) or FPB-type fully premixed metal surface burners to increase the combustion surface to achieve low nitrogen emissions. However, the FGR nitrogen reduction method has many insurmountable disadvantages such as high price and a reduction in boiler energy efficiency of about 3-5%. FPB surface metal burners are criticized by people because of the metal mesh combustion surface on the surface, which is easy to block, low combustion efficiency, burnout and backfire. At the same time, the water in the boiler will become steam at the end of the coil or serpentine tube, the tube will burn dry, and the dry burning temperature is high, which is easy to deform, burn, and scale. Summary of the invention

[0004] The present invention aims to solve the above-mentioned technical problems existing in the gas steam generator of the prior art, and provides a heat transfer enhanced vertical pipe water-cooled gas steam generator with high heat exchange efficiency, low combustion temperature and exhaust temperature, low cost and low nitrogen emission, no dry burning, and long service life.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a heat transfer enhanced vertical tube water-cooled gas steam generator, comprising an upper header and a lower header; a main steam valve pipe is arranged on the top of the upper header; a tube-type membrane water-cooled wall is arranged between the upper header and the lower header, the upper and lower ends of the tube-type membrane water-cooled wall are respectively connected with the upper header and the lower header, and a relative gas inlet and flue gas outlet are arranged on the tube-type membrane water-cooled wall, the gas inlet is connected with an air intake bin, the air intake bin is connected with a premixing fan, a water-cooled flat burner is arranged in the air intake bin, the water-cooled flat burner comprises a water-cooled fire row tube bundle and an igniter, and the space between the water-cooled fire row tube bundle and the air intake bin forms an air distribution chamber; the water-cooled fire row tube bundle and the tube-type membrane water-cooled wall are combined A combustion furnace cavity is formed around the combustion furnace cavity, and an enhanced convection heat exchange tube bundle is arranged in the combustion furnace cavity, and the upper and lower ends of the enhanced convection heat exchange tube bundle are respectively connected with the upper header and the lower header; the space occupied by the enhanced convection heat exchange tube bundle in the combustion furnace cavity forms a heat exchange chamber, and the space between the enhanced convection heat exchange tube bundle furnace and the water-cooled fire row tube bundle in the combustion furnace cavity forms a combustion chamber; the igniter is arranged on the air intake bin on one side of the combustion chamber; the smoke gas outlet is connected to the tail normal pressure economizer, and the tail normal pressure economizer is connected to the smoke collecting box, and a chimney is arranged on the smoke collecting box; the water inlet of the lower header and the water outlet of the tail normal pressure economizer are connected through a pipeline and a water pump; a liquid level gauge tube is connected between the lower header and the upper header, and a liquid level gauge is connected to the liquid level gauge tube. The present invention optimizes and improves the structure of the steam generator. The overall material of the present invention can be stainless steel or carbon steel. The present invention adopts a low-cost water-cooled flat burner for low-temperature water-cooled combustion, which reduces the combustion temperature and greatly reduces the generation of nitrogen oxides; the enhanced convection heat exchange tube bundle is used for heat exchange, which is beneficial to improve the heat exchange effect. The heat exchange efficiency can be increased by about 30%, which is beneficial to reduce the overall consumables and water volume of the steam generator (controlled below 30 liters without dry burning); the fan is arranged with a side spray, and the side spray setting prevents the premixing fan from being corroded and dampened by condensed water caused by flue gas flowing back to the premixing fan after shutdown; the tube-type membrane water cooling The wall surrounds the combustion chamber and the heat exchange chamber to form a closed combustion furnace chamber. The shell and tube membrane water-cooled wall increases the heat exchange area, improves thermal efficiency, and reduces the surface temperature of the generator. The outer side of the shell and tube membrane water-cooled wall can be affixed with a heat insulation layer or a thermal insulation layer; there is a water level electrode in the liquid level gauge, and the water level electrode transmits the water level signal to the water level controller to control the start and stop of the water pump, and pumps water into the lower collecting tank for water replenishment, so as to ensure that the water level in the enhanced convection heat exchange tube bundle is always maintained within a certain range, avoid dry burning and scaling of the enhanced convection heat exchange tube bundle, and extend the service life. Controlling the start and stop of the water pump by water level electrodes and water level controllers is a conventional means in this field, so it is not described in detail.

[0006] Preferably, the water-cooled fire bar tube bundle is composed of a plurality of vertically parallel finned tubes, wherein the finned tubes include water-cooled tubes and fins, and the fins are fixed to the outer circumferential surface of the water-cooled tubes and are spaced apart along the axial direction of the water-cooled tubes.

[0007] Preferably, the water-cooled flat burner further comprises an air distribution plate, which is fixed to the outside of the water-cooled fire row tube bundle, and the fin is provided with two chamfers on the side close to the air distribution chamber, and a V-shaped guide plate is provided between adjacent water-cooled tubes, and the inclined surfaces of the V-shaped guide plate are respectively fixedly connected to the chamfers on the adjacent fins on both sides, and a gap is provided between adjacent V-shaped guide plates, and the gap forms an air intake channel, and the air distribution plate is provided with air distribution holes connected to the air intake channel. The V-shaped guide plate in the present invention can increase the length of the premixed gas water cooling channel and play a role in preventing backfire; the combustion of gas on the finned tube can reduce the combustion temperature and achieve ultra-low nitrogen emissions.

[0008] Preferably, a pressure gauge pipe and a safety valve pipe are also provided on the top of the upper header.

[0009] Preferably, the enhanced convection heat exchange tube bundle is composed of at least one of a plurality of vertically distributed rows of twisted tubes, finned tubes and plain tubes.

[0010] Preferably, the tube-in-tube membrane water-cooled wall comprises water-cooled wall tubes and connecting fins, and the water-cooled wall tubes are welded into an integral structure through the connecting fins.

[0011] Preferably, the tail normal pressure economizer includes a shell and a cold water tube bundle arranged in the shell, the cold water tube bundle is composed of multiple rows of finned tubes arranged horizontally, the shell is provided with a water inlet chamber and a water outlet chamber on both sides, the two ends of the finned tube are connected to the water inlet chamber and the water outlet chamber respectively, and the water inlet of the lower header is connected to the water outlet on the water outlet chamber through a pipeline and a water pump. The cold water tube bundle is distributed horizontally. This design can not only reduce the smoke resistance, but also make the condensed water on the fins drip naturally or be blown off by the smoke, and it is not easy to accumulate dust and blockage (self-cleaning effect).

[0012] Preferably, the liquid level gauge tube and the liquid level gauge are located outside the furnace body. The liquid level gauge tube and the liquid level gauge are located outside the furnace body and are not heated to ensure the accuracy of the water level.

[0013] Preferably, the smoke collecting box is in a conical square bucket shape, and the chimney is vertically arranged on the smoke collecting box.

[0014] Preferably, a sewage pipe is connected to the lower header.

[0015] Therefore, the present invention has the following beneficial effects:

[0016] (1) The combustion and exhaust temperatures are low, and the thermal efficiency can reach over 105%;

[0017] (2) The use of enhanced heat transfer tubes can increase the heat exchange efficiency by about 30%, which is beneficial to reducing the overall consumables of the steam generator and reducing the overall volume;

[0018] (3) Side spray arrangement of the fan. The side spray arrangement can prevent the flue gas from flowing back into the premixing fan after the premixing fan is shut down, thereby preventing the condensed water from corroding and dampening the fan;

[0019] (4) The tube-type membrane water-cooled wall surrounds the combustion chamber and the heat exchange chamber to form a closed combustion furnace chamber. The tube-type membrane water-cooled wall can not only increase the heat exchange area and improve the thermal efficiency, but also reduce the surface temperature of the furnace body;

[0020] (5) The water-cooled flat burner has low cost and can be directly assembled and installed in one piece. There is no need to purchase burners from outside. While reducing production costs, it can achieve low-temperature water-cooled combustion of gas, lower the combustion temperature, greatly reduce the generation of nitrogen oxides, and make emissions more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a front half-section view of the present invention.

[0022] Figure 2 It is a top view of a half-section of the present invention.

[0023] Figure 3 yes Figure 2 Enlarged view of point A in the middle.

[0024] In the figure: upper header 1, lower header 2, main steam valve pipe 3, air intake bin 5, igniter 6, air distribution chamber 7, heat exchange chamber 8, combustion chamber 9, smoke collecting box 10, chimney 11, pipeline 12, water pump 13, liquid level gauge tube 14, liquid level gauge 15, water cooling tube 16, fin 17, air distribution orifice plate 18, V-shaped guide plate 19, air intake channel 20, air distribution hole 21, pressure gauge tube 22, safety valve tube 23, water-cooled wall tube 24, connecting fin 25, cold water tube bundle 26, water inlet chamber 27, water outlet chamber 28, sewage pipe 29, enhanced convection heat exchange tube bundle 30, premixing fan 31, shell 32. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0026] like Figure 1 , Figure 2The enhanced heat transfer vertical tube water-cooled gas steam generator shown in the figure comprises an upper header 1 and a lower header 2, both of which are circular; the top of the upper header is connected to a main steam valve pipe 3, a pressure gauge pipe 22 and a safety valve pipe 23, and the lower header is connected to a sewage pipe 29; a tube-type membrane water-cooled wall is arranged between the upper header and the lower header, the tube-type membrane water-cooled wall comprises a water-cooled wall tube 24 and a connecting fin 25, and the water-cooled wall tubes are welded into an integral structure through connecting fins, and the upper and lower ends of the water-cooled wall tubes in the tube-type membrane water-cooled wall are respectively connected to the upper header and the lower header, and a relative gas inlet and flue gas outlet are arranged on the tube-type membrane water-cooled wall, the gas inlet is connected to an air intake bin 5, and the air intake bin is connected to a premixing The fan 31 has a water-cooled flat burner in the air inlet bin. The water-cooled flat burner includes a water-cooled fire row tube bundle, an igniter 6 and an air distribution orifice plate 18. The water-cooled fire row tube bundle is composed of a plurality of vertically parallel finned tubes. The finned tube includes a water-cooled tube 16 and a fin 17. The fin is fixed on the outer circumferential surface of the water-cooled tube and is arranged at intervals along the axial direction of the water-cooled tube. The air distribution orifice plate is fixed on the outside of the water-cooled fire row tube bundle. Two chamfers are provided on the side of the fin close to the air distribution chamber. A V-shaped guide plate 19 is provided between adjacent water-cooled tubes. The inclined surfaces of the V-shaped guide plate are respectively fixedly connected to the chamfers on the adjacent fins on both sides. A gap is provided between adjacent V-shaped guide plates, and the gap forms an air inlet channel 20. The air distribution orifice plate is provided with a chamfer that is connected to the air inlet channel. The air distribution holes 21 are connected; the space between the water-cooled fire row tube bundle and the air inlet bin forms an air distribution chamber 7; the water-cooled fire row tube bundle and the tube-type membrane water-cooled wall are combined to form a combustion furnace chamber, and an enhanced convection heat exchange tube bundle 30 is arranged in the combustion furnace chamber, and the enhanced convection heat exchange tube bundle is composed of three rows of vertically distributed light tubes and two rows of finned tubes, wherein the light tubes are located in front of the finned tubes; the upper and lower ends of the light tubes and finned tubes in the enhanced convection heat exchange tube bundle are respectively connected to the upper header and the lower header; the space occupied by the enhanced convection heat exchange tube bundle in the combustion furnace chamber forms a heat exchange chamber 8, and the space between the enhanced convection heat exchange tube bundle furnace and the water-cooled fire row tube bundle in the combustion furnace chamber forms a combustion chamber 9, and the igniter is arranged on the air inlet bin on one side of the combustion chamber; The flue gas outlet is connected to a tail normal pressure economizer, which includes a shell 32 and a cold water tube bundle 26 arranged in the shell. The cold water tube bundle is composed of multiple rows of transversely arranged finned tubes. A water inlet chamber 27 and a water outlet chamber 28 are respectively provided on both sides of the shell. The two ends of the finned tube are respectively connected to the water inlet chamber and the water outlet chamber. The water inlet of the lower header and the water outlet on the water outlet chamber of the tail normal pressure economizer are connected through a pipeline 12 and a water pump 13. The shell of the tail normal pressure economizer is connected to a smoke collecting box 10. The smoke collecting box is in a conical square bucket shape, and a chimney 11 is vertically arranged on the smoke collecting box; a liquid level gauge tube 14 is connected between the lower header and the upper header, and a liquid level gauge 15 is connected to the liquid level gauge tube. The liquid level gauge tube and the liquid level gauge are located outside the furnace body.

[0027] The operation process of the present invention is as follows: the premixing fan mixes the gas and air and sends them into the air distribution chamber, which are redistributed in the air distribution chamber and then enter the combustion chamber. Under the action of the ignition device, the combustion is carried out in the combustion chamber, and the high-temperature flue gas generated by the combustion is heat-exchanged with the enhanced convection heat exchange tube bundle in the heat exchange chamber. The water in the enhanced convection heat exchange tube bundle is heated to become steam and rises to the upper header and is discharged from the main steam valve pipe; the high-temperature flue gas after the heat exchange enters the tail economizer and is heat-exchanged with the cold water tube bundle in the tail economizer, and the waste heat is used to preheat the incoming water, while further reducing the flue gas temperature; there is a water level electrode in the liquid level gauge, and the water level electrode transmits the water level signal to the water level controller to control the start and stop of the water pump, and the water in the water outlet chamber is pumped into the lower header for water replenishment, so as to ensure that the water level in the enhanced convection heat exchange tube bundle is always kept within a certain range, avoiding dry burning and scaling of the enhanced convection heat exchange tube bundle; the flue gas cooled by the cold water tube bundle finally enters the smoke collecting box and is discharged from the chimney.

[0028] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A water-cooled gas steam generator with enhanced heat transfer riser, characterized in that: The invention comprises an upper header (1) and a lower header (2); a main steam valve pipe (3) is provided on the top of the upper header (1); a tube-type membrane water-cooled wall is provided between the upper header (1) and the lower header (2); the upper and lower ends of the tube-type membrane water-cooled wall are respectively connected to the upper header (1) and the lower header (2); a gas inlet and a smoke outlet are provided on the tube-type membrane water-cooled wall; the gas inlet is connected to an air intake bin (5); the air intake bin (5) is connected to a premixing fan (31); a water-cooled flat burner is provided in the air intake bin (5); the water-cooled flat burner comprises a water-cooled fire row tube bundle and an igniter (6); the space between the water-cooled fire row tube bundle and the air intake bin (5) forms an air dividing chamber (7); the water-cooled fire row tube bundle and the tube-type membrane water-cooled wall are surrounded to form a combustion furnace chamber; an enhanced convection heat exchange tube bundle (30) is provided in the combustion furnace chamber; the enhanced convection heat exchange tube bundle (30) is provided in the combustion furnace chamber; The upper and lower ends of the enhanced convection heat exchange tube bundle (30) are respectively connected to the upper header (1) and the lower header (2); the space occupied by the enhanced convection heat exchange tube bundle (30) in the combustion furnace cavity forms a heat exchange chamber (8), and the space between the enhanced convection heat exchange tube bundle (30) and the water-cooled fire row tube bundle in the combustion furnace cavity forms a combustion chamber (9); the igniter (6) is arranged on an air inlet bin (5) on one side of the combustion chamber (9); the smoke gas outlet is connected to a tail normal pressure economizer, and the tail normal pressure economizer is connected to a smoke collecting box (10), and a chimney (11) is provided on the smoke collecting box (10); the water inlet of the lower header (2) and the water outlet of the tail normal pressure economizer are connected via a pipeline (12) and a water pump (13); a liquid level gauge tube (14) is connected between the lower header (2) and the upper header (1), and a liquid level gauge (15) is connected to the liquid level gauge tube (14).

2. The heat transfer enhanced vertical tube water-cooled gas steam generator according to claim 1, characterized in that: The water-cooled fire row tube bundle is composed of a plurality of vertically parallel finned tubes, wherein the finned tubes include a water-cooling tube (16) and fins (17), wherein the fins (17) are fixed to the outer circumferential surface of the water-cooling tube (16) and are arranged at intervals along the axial direction of the water-cooling tube (16).

3. The heat transfer enhanced vertical tube water-cooled gas steam generator according to claim 2, characterized in that: The water-cooled flat burner also includes an air distribution plate (18), the air distribution plate (18) being fixed to the outside of the water-cooled fire row tube bundle, the fin (17) being provided with two chamfers on the side close to the air distribution chamber (7), a V-shaped guide plate (19) being provided between adjacent water-cooled tubes (16), the inclined surfaces of the V-shaped guide plate being respectively fixedly connected to the chamfers on the adjacent fins (17) on both sides thereof, a gap being provided between adjacent V-shaped guide plates, the gap forming an air intake channel (20), and an air distribution hole (21) being connected to the air intake channel being provided on the air distribution plate (18).

4. The heat transfer enhanced vertical tube water-cooled gas steam generator according to claim 1, characterized in that: A pressure gauge tube (22) and a safety valve tube (23) are also provided on the top of the upper header (1).

5. The heat transfer enhanced vertical tube water-cooled gas steam generator according to claim 1, characterized in that: The enhanced convection heat exchange tube bundle (30) is composed of at least one of a plurality of vertically distributed rows of twisted tubes, finned tubes, and plain tubes.

6. The heat transfer enhanced vertical tube water-cooled gas steam generator according to claim 1, characterized in that: The tube-in-tube membrane water-cooled wall comprises water-cooled wall tubes (24) and connecting fins (25), and the water-cooled wall tubes are welded into an integrated structure via the connecting fins (25).

7. The heat transfer enhanced vertical tube water-cooled gas steam generator according to claim 1, characterized in that: The tail normal pressure economizer comprises a shell (32) and a cold water tube bundle (26) arranged in the shell (32), the cold water tube bundle (26) being composed of a plurality of rows of transversely arranged fin tubes, a water inlet chamber (27) and a water outlet chamber (28) being respectively arranged on both sides of the shell (32), the two ends of the fin tube being respectively connected to the water inlet chamber (27) and the water outlet chamber (28), and the water inlet of the lower header (2) and the water outlet on the water outlet chamber (28) being connected via a pipeline (12) and a water pump (13).

8. The heat transfer enhanced vertical tube water-cooled gas steam generator according to claim 1, characterized in that: The smoke collecting box (10) is in the shape of a conical square bucket, and the chimney (11) is vertically arranged on the smoke collecting box (10).

9. The heat transfer enhanced vertical tube water-cooled gas steam generator according to claim 1, characterized in that: The lower header (2) is connected to a sewage discharge pipe (29).

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