CN211011926U - A cylindrical slot type fully premixed water-cooled combustion head structure - Google Patents

Abstract

The utility model discloses a cylindrical slot type fully premixed water-cooled combustion head structure, which comprises a water-cooled tube bundle, a header, a base and a top cover to form a cylindrical combustion head; It is composed of straight finned tubes, fan annular straight tubes, and can also be composed of multi-section spiral finned coils, oval or rectangular coils with gaps along the circumferential direction; After the premixed gas leaves the gap, the high-temperature flue gas around the gap is entrained, and the high-temperature flue gas washes the surface of the water-cooled tube bundle and is cooled down, thereby reducing the flame temperature, reducing the generation of thermal nitrogen oxides, and realizing NOx under the condition of oxygen content <3.5% <30mg/ ^Nm3 target. The cylindrical burner head can be adapted to low nitrogen retrofits of all old gas boiler furnaces and replaces all traditional diffusion and full premix burners.

Description

A cylindrical slot type fully premixed water-cooled combustion head structure

technical field

The utility model relates to the technical field of burners, in particular to a water-cooled cylindrical slit type fully premixed water-cooled combustion head structure.

Background technique

In recent years, the problem of haze has persisted. Although most coal-fired units have completed ultra-low emission transformation (NOx<50mg/Nm ³ , SO ₂ <35mg/Nm ³ , PM10<5mg/Nm ³ ), most gas-fired boilers have also completed Low nitrogen transformation (NOx<80mg/ ^Nm3 ). Diffusion-type low-nitrogen gas burners currently ^on the market use air grading and fuel grading technologies, and assist external flue gas circulation or internal flue gas circulation. The external circulation fan increases the total flue gas volume when the boiler is burning, resulting in a decrease in the output of the boiler and an increase in operating costs; the flue gas internal circulation technology requires high gas and air pressure, and the use effect is not good in the winter heating period when the gas pressure is low. good. The fully premixed burner has also achieved the goal of NOx<30mg/ ^Nm3 by increasing the air-fuel ratio, increasing the oxygen content, reducing the combustion temperature, and narrowing the high temperature zone of the flame, but the higher oxygen content (>6%) increases the boiler The heat loss of exhaust smoke increases the difficulty of utilizing the latent heat of water vapor, which reduces the overall efficiency of the boiler by more than 2%; at the same time, in order to prevent the metal orifice plate from drying out and stabilizing the flame, a layer of metal fiber mesh is usually covered outside the metal orifice plate. There is a risk of clogging and burning of the net. At present, a new type of water-cooled panel-type fully premixed low-nitrogen burner has appeared on the market, which combines the advantages of low-oxygen diffusion burner and compactness of full-premixed burner. At the same time, the oxygen content can still be controlled below 3.5%.

At present, the water-cooled burners CN201820985795.X and CN201820203423.7 applied by Guangdong Wanhe Company are all flat plate structures and can only be used for small wall-hung boilers; The flat water-cooled tube row cools the flame. When the power of the burner increases, the area of the flat plate can only be increased. However, as the power of the boiler increases, the volume of the burner panel becomes larger and larger, and the layout space on the boiler is insufficient. When the panel-type water-cooled burner is used for the low-nitrogen renovation of the old unit, the front furnace wall of the boiler needs to be removed, and part of the heating surface of the boiler needs to be replaced, which requires a huge amount of renovation work.

In order to solve the problems that the flat water-cooled combustion head is difficult to enlarge and adapt to the low-nitrogen transformation of old gas boilers or gas devices, a cylindrical slot water-cooled combustion head is proposed. The premixed gas is ejected from the gap between the water-cooled tube bundles and ignited. Combustion, the cylindrical burner head can be adapted to the low nitrogen retrofit of all old gas boiler furnaces and replaces all traditional diffusion and full premix burners. With the increase of boiler power, the diameter and length of the combustion head can be increased at the same time, so as to achieve the matching between the volume of the combustion head and the space of the boiler furnace under all powers.

SUMMARY OF THE INVENTION

In order to solve the problems that the plate water-cooled burner is difficult to enlarge and adapt to the low-nitrogen transformation of old gas-fired boilers or gas-fired devices, the purpose of the present invention is to provide a cylindrical slot type fully premixed water-cooled combustion head structure, which is suitable for all The furnace of the old gas boiler is replaced by the traditional diffusion and full premixed burners. The premixed gas is injected from the gap between the water-cooled tube bundles for combustion, and the high-speed premixed gas leaves the gap and entrains the high-temperature flue gas around the gap. , the surface of the water-cooled tube bundle is cooled by high-temperature flue gas flushing, thereby reducing the flame temperature, reducing the generation of thermal nitrogen oxides, and achieving the target of NOx<30mg/ ^Nm3 under the condition of oxygen content <3.5%.

In order to achieve the above purpose, the utility model adopts the following technical solutions:

A cylindrical slot type fully premixed water-cooled combustion head structure is composed of a water-cooled tube bundle 1, a header 2, a base 3 and a top cover 4 to form a cylindrical combustion head; Gap; the flange end of the base 3 is connected to the gas-air mixing chamber of the full premix burner to support the entire combustion head; when the header 2 is built in, the round end of the base 3 is connected to the water-cooled tube bundle 1, and the top cover 4 is connected to The open side of the water-cooled tube bundle 1 is connected to seal the combustion head; when the header 2 is placed outside, the header 2 consists of an annular bottom header 2-1 and a top header 2-2, and the round end of the base 3 is connected to the bottom The header 2-1 is connected, the top cover 4 is connected to the open side of the top header 2-2, the combustion head is sealed, and the water-cooled tube bundle 1 is located between the bottom header 2-1 and the top header 2-2; the combustion head is located in Inside the furnace, the premixed gas enters the water-cooled tube bundle 1 from the gas-air mixing chamber outside the furnace along the base 3, leaves the combustion head from the gap of the water-cooled tube bundle 1, and enters the furnace space for ignition and combustion. The surface of the water-cooled tube bundle 1 is washed with the high-temperature flue gas of the entrained furnace, and the cooled high-temperature flue gas of the furnace is mixed with the premixed gas and ignited and burned.

When the header 2 is placed outside, the water-cooled tube bundle 1 is a straight finned tube with a slit parallel to the axial direction without fins, a fan-shaped straight tube, and the header 2 is in direct contact with the flue gas; the bottom header 2 -1 and the top header 2-2 are composed of multiple fan-shaped water chambers, and the cooling water changes the flow direction at the fan-shaped water chambers; the bottom header 2-1 has a water inlet 2-11 and a water outlet 2-12, which are connected with the boiler Water system connection; divide the water-cooled tube bundle 1 into an even group of unit tube bundles 1-1, each group of unit tube bundles 1-1 consists of 1 to 16 tubes; 1-1 flows to the top header 2-2, turns 180° at the top header 2-2, and flows along the adjacent unit bundle 1-1 to the bottom header 2-1, at the bottom header 2-1 Turn 180°, and then flow along the adjacent unit tube bundle 1-1 to the top header 2-2, and repeat this process until it leaves the water outlet 2-12 on the bottom header 2-1.

The finned straight tube is composed of a base tube and an external spiral fin or a base tube and an external flat fin; the welding method between the base tube and the fin adopts high-frequency welding or laser welding; the fin height of the fin is The diameter of the base pipe is 0.1 to 0.6 times, the thickness of the fins is 0.2 to 1.2 mm, and the fin spacing is 0.8 mm to 4 mm. The smaller fin spacing helps to reduce the flow area, increase the flow rate of the premixed gas at the outlet, and prevent tempering; for strengthening The cooling ability of the finned tube to the flame reduces the flow area of the premixed gas, the fins of the tube bundle are folded, and the edge of the spiral fin is bent by 60° to 120°. The top view changes from a circle to a polygon with a combination of arcs and straight lines. The cladding surface of the spiral fin straight tube changes from a cylindrical shape to a combination of an arc surface and a folded fin surface. When the edge part of the spiral fin is bent at multiple angles , there are 2 to 8 folded fin surfaces at the same time, and the height of the fin edge part of the folded fin treatment is 1 to 6 mm; The folded fin surfaces of the fins are close together to form an annular water-cooled tube bundle 1; if the fin straight tube is composed of a base tube and an additional flat fin, the flat fins are strung onto the base tube, and then the fins are folded.

The fan-shaped straight pipe has a fan-shaped cross-sectional shape, and the fan-shaped straight pipe is evenly surrounded by a circle in the circumferential direction to form an annular water-cooled tube bundle 1; The flow velocity at the gap between the straight pipes reaches 8m/s to 40m/s, which is much higher than the tempering flow velocity, achieving a regulation ratio of 1:15; the straight pipe without fins has a circular cross-section, and the outer The distance between the surfaces is less than 5mm.

The water-cooled tube bundle 1 when the header 2 is placed outside adopts a double-layer arrangement to form a two-layer annular tube bundle; the inner layer is a fan-shaped straight tube, a straight tube without fins, and a cylindrical orifice plate 5; the outer layer is a fan-shaped ring Straight tube, straight tube without fins, straight tube with fins, a total of 9 combinations; the cylindrical orifice plate 5, the opening area of the orifice plate accounts for 1% to 50%, which can equalize the flow and prevent backflow. Fire function, the outer layer is fan-shaped straight tube and finned straight tube; when the header 2 is externally placed, the water-cooled tube bundle 1, the arc section of any angle along the radial direction can be independently used as the combustion head, and the two arbitrary angles can be used independently. A part of the cylindrical combustion head after sealing the upper and lower surfaces and at any angle constitutes a fan annular combustion head. The premixed gas enters the fan annular combustion head from the premixed gas inlet surface, and enters the furnace from the gap of the water-cooled tube bundle 1 for combustion.

When the header 2 is built in, the gap of the water-cooled tube bundle 1 is along the circumferential direction. At this time, the water-cooled tube bundle 1 is a spiral fin coil, an oval or a rectangular coil; the header 2 is placed inside the combustion head corresponding to the base 3 The space is divided into two parts: the inlet header 2-3 and the outlet header 2-4. The inlet header 2-3 and the outlet header 2-4 are located in different rings. The water inlet pipe of the inlet header 2-3 is 2- 31 and the water outlet pipes 2-41 of the outlet header 2-4 extend to the flange of the base 3 and connect with the boiler water system; the coils are connected in parallel with multiple sections or only use one section of the coils. When the coils are connected in parallel with multiple sections, The inlet and outlet of each coil section first extend radially inward to the corresponding annular space of the header, and then extend axially to the inlet header 2-3 and the outlet header 2-4; The lengths are equal or unequal, and the non-complete circles of each section of the coil are added together to form a complete circle, so that the interval angle between the inlet or outlet of each section of the coil is exactly the same; the inlet and outlet of each section of the coil are located in the disk Outside the pipe section, it is convenient for welding connection with the header 2; when the coil only uses one section of the coil, there is no need to set the inlet header 2-3 and the outlet header 2-4. At this time, the water inlet pipe of the coil is 2-31 And the outlet pipe 2-41 extends to the flange of the base 3 in the axial direction.

The spiral fin coiled tube is formed by the spiral fin straight tube processed by folding fins along the spiral line with the axis of the cylindrical water-cooled combustion head as the center line; the adjacent spiral fin tubes are in contact, and the contact surface is the folding fin. On the folded fin surface formed after treatment, the pitch of the helix is smaller than the outermost diameter of the helical fin tube, which reduces the area of flue gas circulation, increases the flow rate of the premixed gas, and prevents tempering; the premixed gas flows from between the spiral fins. The gap enters the furnace to ignite and burn.

The oblong or rectangular coil is formed by coiling a straight pipe with an oblong or rectangular section along a helix with the axis of the cylindrical water-cooled combustion head as the center line, and the pitch of the helix is greater than the height of the straight pipe section. , to form a spiral gap, and the premixed gas enters the furnace from the spiral gap to ignite and burn; in order to prevent tempering, the gap size is 0.2-4mm to increase the flow rate of the premixed gas at the gap.

When the water-cooled tube bundle 1 is a multi-section spiral fin coil, oval or rectangular coil, there will be a spiral gap between the base 3 and the top cover 4 and the coil, in order to prevent the premixed gas from passing through the spiral gap. If there is leakage, use spiral refractory material or heat-resistant steel to fill the gap.

The cylindrical slot type fully premixed water-cooled combustion head is a part of the heating surface of the boiler, and needs to be fed into the boiler working fluid for cooling; if it is a gas-fired steam boiler, the water-cooled combustion head takes water from before or after the condenser, and then returns it to the original place ; If it is a gas-fired hot water boiler, take water from any position and send it to the water-cooled combustion head, and then send it back to the original place.

The innovation points, advantages and positive effects of the present utility model are:

1. A cylindrical gap type fully premixed water-cooled combustion head of the present invention adopts the design concept of narrow gap and high flow rate, and the flow rate of the premixed gas when passing through the narrow gap is much higher than the tempering speed, so that the adjustment ratio of the burner can be adjusted. up to 1:10 or more.

2. A cylindrical slot type fully premixed water-cooled combustion head of the present invention can adopt a double-layer water-cooled structure, the inner layer of water-cooled tube bundles can prevent tempering, and the outer layer of water-cooled tube bundles has a larger gap and a lower flow rate, forming a blunt tube. Body turbulence, flame stabilization and fire prevention effect.

3. A cylindrical slot type fully premixed water-cooled combustion head of the present invention is a part of the heating surface of the boiler, which can improve the thermal efficiency of the boiler for the renovation of the old boiler; part of the heat exchange area.

4. A cylindrical slot type fully premixed water-cooled combustion head of the present utility model utilizes high-speed premixed gas to inject high-temperature flue gas in the furnace chamber back to the surface of the water-cooled combustion head for cooling, and the cooled high-temperature flue gas is mixed with the premixed gas Combustion, the excess air coefficient is increased, the theoretical combustion temperature is lowered, and NOx<30mg/Nm ³ can be achieved under the condition of oxygen content<3.5%.

5. The oxygen content of the flue gas after the combustion of a cylindrical slot type fully premixed water-cooled combustion head of the present invention can be controlled below 3.5%, and the excess air coefficient is less than 1.2, which significantly increases the volume fraction of water vapor in the flue gas, and improves the performance of the flue gas. Water dew point, water vapor is more likely to condense and separate out, reducing the volume of the condensing heat exchanger; compared with the excess air coefficient of the traditional full premix burner up to 1.4, it reduces the amount of additional heated air and reduces the heat loss of boiler exhaust gas. Increased boiler efficiency.

Description of drawings

1 is an overall schematic diagram of a cylindrical slot type fully premixed water-cooled combustion head of the present invention, wherein: FIG. 1 a is an overall schematic diagram of a spiral fin straight pipe; FIG. 1 b is an overall schematic diagram of a fan ring straight pipe; Overall schematic diagram of a helical fin coil; Figure 1d is an overall schematic diagram of an oblong or rectangular coil.

Figure 2 is a schematic diagram of the header water circuit when the gap of a cylindrical slot type fully premixed water-cooled combustion head of the present invention is parallel to the axial direction; Figure 2a is an overall schematic diagram; Figure 2b (1) is a schematic diagram of the bottom header, Figure 2b (2) is a schematic diagram of the top header.

3 is a schematic diagram of a spiral fin straight tube of a cylindrical slot type fully premixed water-cooled combustion head of the present invention; FIG. 3 a is a diagram of the spiral fin straight tube with fins folded, and FIG. 3 b is a three-dimensional schematic diagram after the folded fins are processed , Figure 3c is a top view.

4 is a schematic cross-sectional view of a fan-shaped straight pipe of a cylindrical slot type fully premixed water-cooled combustion head of the present invention.

5 is a schematic cross-sectional view of a double-layer water-cooled tube bundle of a cylindrical slot type fully premixed water-cooled combustion head of the present invention, wherein, FIG. 5a is a section of a straight fan-shaped tube in the inner layer and a straight tube with spiral fins in the outer layer. Schematic diagram; Figure 5b is a schematic cross-sectional view of the inner layer and the outer layer being a fan-shaped straight pipe; Figure 5c is a cross-sectional view of a cylindrical orifice plate 5 in the inner layer, and Figure 5d (1) The premixed gas inlet surface is located on the inner arc surface, Figure 5d(2) The inlet surface of the premixed gas is located on the outer arc surface.

6 is a schematic diagram of the header water path when the slit of a cylindrical slot type fully premixed water-cooled combustion head of the present invention is parallel to the circumferential direction, wherein FIG. 6a is an overall three-dimensional schematic diagram; Schematic.

7 is a schematic diagram of a spiral fin coil of a cylindrical slot type fully premixed water-cooled combustion head of the present invention.

Fig. 8 is a cross-sectional schematic diagram of a rectangular coil tube of a cylindrical slot type fully premixed water-cooled combustion of the present invention.

FIG. 9 is a schematic diagram of the spiral gap filling of a cylindrical gap type fully premixed water-cooled combustion head according to the present invention.

Detailed ways

The utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, a cylindrical slot type fully premixed water-cooled combustion head of the present invention is composed of a water-cooled tube bundle 1, a header 2, a base 3 and a top cover 4 to form a cylindrical combustion head with an overall shape; the water-cooled tube bundle 1 There is a gap between the pipes of the base 3; the flange end of the base 3 is connected to the gas-air mixing chamber of the full premix burner to support the entire combustion head; when the header 2 is built in, the round end of the base 3 is connected to the water cooling The tube bundle 1 is connected, and the top cover 4 is connected to the open side of the water-cooled tube bundle 1 to seal the combustion head; when the header 2 is placed outside, the header (2) consists of an annular bottom header 2-1 and a top header 2-2 Composition, the round end of the base 3 is connected with the bottom header 2-1, the top cover 4 is connected with the open side of the top header 2-2, the combustion head is sealed, and the water-cooled tube bundle 1 is located in the bottom header 2-1 and the top header. Between boxes 2-2; the combustion head is located inside the furnace, and the premixed gas enters the water-cooled tube bundle 1 from the gas-air mixing chamber outside the furnace along the base 3, leaves the combustion head from the gap of the water-cooled tube bundle 1, and enters the furnace space for ignition and combustion. The flow velocity of the premixed gas leaving the gap is relatively high, and the high temperature flue gas of the entrained furnace will wash the surface of the water-cooled tube bundle 1, and the cooled high temperature flue gas of the furnace will be mixed with the premixed gas and ignited and burned.

When the header 2 is placed outside, as shown in Figures 1a and 1b, the water-cooled tube bundle 1 is a finned straight tube or a fan-shaped straight tube with a slit parallel to the axial direction, as shown in Figure 2a and Figure 2b (1 ) and as shown in Figure 2b(2), the header 2 is composed of an annular bottom header 2-1 and a top header 2-2, the header 2 is in direct contact with the flue gas; the bottom header 2-1 And the top header 2-2 is composed of multiple fan-shaped water chambers, and the cooling water changes the flow direction at the fan-shaped water chambers; the bottom header 2-1 has a water inlet 2-11 and a water outlet 2-12, which are connected with the boiler water system. Connection; divide the water-cooled tube bundle 1 into 4 groups of unit tube bundles 1-1, each group of unit tube bundles 1-1 is composed of 4 tubes; after cooling water enters the water-cooled combustion head from the water inlet 2-11, it follows the unit tube bundle 1-1 Flow to top header 2-2, 180° turn at top header 2-2, flow along adjacent unit bundle 1-1 to bottom header 2-1, 180° turn at bottom header 2-1 , and then flow along the adjacent unit tube bundle 1-1 to the top header 2-2, and repeat this process until it leaves the water outlet 2-12 on the bottom header 2-1.

As shown in Figure 3a, in order to strengthen the cooling ability of the finned tube to the flame and reduce the flow area of the premixed gas, the fins of the tube bundle can be folded, and some edge fins are bent 90°, and the fins are folded. The height of the fins is 1-6mm; the edge fins on the same side are bent in the same folded fin surface, with a total of 2 folded fin surfaces, as shown in Figure 3b, the angle between the folded fin surfaces is about 22.5°; The top view of the treated fin is shown in Figure 3-c. It consists of two arcs and two straight segments. The straight spiral fin tube is evenly surrounded by a circle in the circumferential direction, and the folded fins of the adjacent spiral fin straight tube The surfaces are close together to form an annular water-cooled tube bundle 1.

As shown in Figure 4, the fan-shaped straight pipe has a fan-shaped cross-section, and the fan-shaped straight pipe is evenly surrounded by a circle in the circumferential direction to form an annular water-cooled tube bundle 1; 3mm, the flow rate of the premixed gas through the gap between the straight pipes can reach 8m/s ~ 40m/s, which is much higher than the tempering flow rate, achieving a regulation ratio of 1:15.

As shown in Figure 5, the water-cooled tube bundles 1 when the header 2 is externally placed can be arranged in two layers to form a two-layer annular tube bundle; the inner layer of Figure 5a is a fan-shaped straight tube, which is arranged in a close-packed arrangement to prevent tempering under low load. , increase the adjustment ratio, the outer layer is a spiral fin straight tube, and the finned tube has a larger heat exchange area, which is conducive to cooling the flame; Figure 5b The inner layer is a ring-shaped straight tube of a dense exhaust fan, and the outer layer is an annular straight tube of a sparse exhaust fan , increase the pipe spacing of the outer straight pipes, so that the flow rate of the premixed gas is lower than 10m/s, and the flame is stabilized; Figure 5c is a cross-sectional view of the cylindrical orifice plate 5 in the inner layer, and the opening area of the orifice plate accounts for 1% to 50%. , play the function of equalizing flow and preventing tempering, and the outer layer is a fan-shaped straight pipe; as shown in Figure 5d, two arbitrary-angle surfaces and a part of the cylindrical combustion head after sealing the upper and lower sides and at any angle constitute a fan-shaped combustion head, which is premixed. The gas enters the inside of the fan annular combustion head from the inlet surface of the premixed gas, and enters the furnace from the gap of the water-cooled tube bundle 1 for combustion. Figure 5d (1) The inlet surface of the premixed gas is located on the inner arc surface, the furnace chamber is outside the outer arc surface, and the premixed gas Burning on the outer arc surface, Figure 5d (2) The inlet surface of the premixed gas is located on the outer arc surface, the furnace chamber is outside the inner arc surface, and the premixed gas is burned on the inner arc surface.

As shown in Fig. 6a and Fig. 6b, when the header 2 is built in, the slits of the water-cooled tube bundle 1 can also be along the circumferential direction, as shown in Fig. 1c and Fig. 1d, at this time, the water-cooled tube bundle (1) is multi-section Spiral fin coil, oval or rectangular coil, the header 2 is placed in the inner space of the combustion head corresponding to the base 3, and is divided into two parts: the inlet header 2-3 and the outlet header 2-4, the inlet header 2 -3 and the outlet header 2-4 are located in different rings, the inlet pipe 2-31 of the inlet header 2-3 and the outlet pipe 2-41 of the outlet header 2-4 extend to the flange of the base 3, Connected to the boiler water system; the number of turns of the 4-stage coil is 12.25 turns, and the inlet and outlet of the 4-stage coil first extend radially inward to the corresponding annular space of the header, and then extend axially to the inlet header. Box 2-3 and outlet header 2-4; the lengths of the 4-section coils can be equal, and the incomplete circles of the 4-section coils can be added to form a complete circle, so that the distance between the inlet or outlet of each section of the coil can be The interval angles are exactly the same; the inlet and outlet of the 4 coils are located outside the coil section, which is convenient for welding connection with the header 2.

As shown in FIG. 7 , the helical fin coil is formed by the previously described fin-folded helical fin straight pipe coiled along a helical line with the axis of the cylindrical water-cooled combustion head as the center line; adjacent helical fins are formed. The finned tubes are in close contact, and the contact surface is the surface formed by folding the fins. The pitch of the helix is smaller than the outermost diameter of the spiral finned tube, which reduces the fin gap area, increases the flow rate of the premixed gas, and prevents tempering; premixed gas Enter the furnace from the gap between the spiral fins to ignite and burn.

As shown in Figure 8, the coiled tube is made of a straight tube with a rectangular cross-section coiled along a spiral line with the axis of the cylindrical water-cooled combustion head as the center line. The pitch of the spiral line is slightly larger than the height of the straight tube section, forming a spiral In order to prevent tempering, the size of the gap is 0.2-4mm, so as to improve the flow rate of the premixed gas at the gap.

As shown in FIG. 9 , when the water-cooled tube bundle 1 is a multi-section spiral fin coil, oval or rectangular coil, there will be a spiral gap between the base 3 and the top cover 4 and the coil, in order to prevent premixed gas It leaks from the spiral gap, and the gap is filled with spiral refractory material or high temperature heat-resistant steel capable of dry burning at 1200℃.

Claims (9)

1. A cylindrical slot type fully premixed water-cooled combustion head structure, characterized in that: the overall shape is cylindrical by being composed of a water-cooled tube bundle (1), a header (2), a base (3) and a top cover (4). Combustion head; a gap is left between the tubes of the water-cooled tube bundle (1); the flange end of the base (3) is connected to the outlet end of the gas-air mixing chamber of the full premix burner to support the entire combustion head; when the header (2) When built in, the round end of the base (3) is connected to the water-cooled tube bundle (1), and the top cover (4) is connected to the open side of the water-cooled tube bundle (1) to seal the combustion head; When installed, the header (2) consists of a ring-shaped bottom header (2-1) and a top header (2-2). The round end of the base (3) is connected to the bottom header (2-1). The cover (4) is connected to the open side of the top header (2-2) to seal the combustion head, and the water-cooled tube bundle (1) is located between the bottom header (2-1) and the top header (2-2). 2. A cylindrical slot type fully premixed water-cooled combustion head structure according to claim 1, characterized in that: when the header (2) is placed outside, the water-cooled tube bundle (1) is a fin straight tube or Straight pipes without fins and fan-shaped straight pipes with slits parallel to the axial direction, the header (2) is in direct contact with the flue gas; the bottom header (2-1) and the top header (2-2) are composed of multiple It consists of a fan-shaped water chamber, and the cooling water changes its flow direction at the fan-shaped water chamber; the bottom header (2-1) has a water inlet (2-11) and a water outlet (2-12), which are connected to the boiler water system; the water cooling The tube bundle (1) is divided into an even group of unit tube bundles (1-1), and each group of unit tube bundles (1-1) is composed of 1 to 16 tubes. 3. A cylindrical slot type fully premixed water-cooled combustion head structure according to claim 2, characterized in that: the fin straight pipe is composed of a base pipe and an externally added helical fin or a base pipe and an externally added plane The fin is composed of; the welding method between the base tube and the fin adopts high-frequency welding or laser welding; 4mm; in order to strengthen the cooling ability of the finned tube to the flame and reduce the flow area of the premixed gas, the fins of the tube bundle are folded, and the edge part of the spiral fin is bent by 60° to 120°. The top view of the helical fin changes from a circle to a polygon with a combination of arcs and straight lines. The cladding surface of the straight pipe of the helical fin changes from a cylindrical shape to a combination of an arc surface and a folded fin surface. The edge of the helical fin is in multiple When the angle is bent, there are 2 to 8 folded fin surfaces at the same time, and the height of the edge part of the fin processed by the folded fin is 1 to 6 mm; The folded fin surfaces of the fin straight tube are closely attached to form an annular water-cooled tube bundle (1). Wing treatment. 4. A cylindrical slot type fully premixed water-cooled combustion head structure according to claim 2, characterized in that: the fan-shaped straight pipe has a fan-shaped cross-section, and the fan-shaped straight pipe is evenly surrounded in the circumferential direction. One circle to form an annular water-cooled tube bundle (1); the fan-shaped straight tubes are densely arranged, and the tube spacing is less than 3 mm; the straight tubes without fins have a circular cross-section, and the distance between the outer surfaces of adjacent tubes is less than 5mm. 5. A cylindrical slot type fully premixed water-cooled combustion head structure according to claim 2, wherein the water-cooled tube bundle (1) when the header (2) is placed outside adopts a double-layer arrangement to form two The inner layer is a fan-shaped straight tube, a straight tube without fins, or a cylindrical orifice plate (5); the outer layer is a fan-shaped straight tube, a straight tube without fins, or a straight finned tube. 9 combinations; the cylindrical orifice plate (5), the opening area of the orifice plate accounts for 1% to 50%, and has the functions of equalizing flow and preventing tempering; when the header (2) is externally placed The water-cooled tube bundle (1), the circular arc section at any angle in the radial direction can be used as a combustion head independently, and the two arbitrary-angle surfaces and a part of the cylindrical combustion head after sealing the upper and lower sides and at any angle constitute a fan annular combustion head, and the premixed gas The premixed gas enters the interior of the fan annular combustion head from the inlet surface of the premixed gas, and enters the furnace for combustion from the gap of the water-cooled tube bundle (1). 6. A cylindrical slot type fully premixed water-cooled combustion head structure according to claim 1, characterized in that: when the header (2) is built in, the gap of the water-cooled tube bundle (1) is along the circumferential direction, and this When the water-cooled tube bundle (1) is a spiral fin coil, oval or rectangular coil; the header (2) is placed in the inner space of the combustion head corresponding to the base (3), and is divided into the inlet header (2-3) and the The outlet header (2-4) has two parts, the inlet header (2-3) and the outlet header (2-4) are located in different rings, and the water inlet pipe (2-31) of the inlet header (2-3) The water outlet pipe (2-41) of the outlet header (2-4) and the outlet header (2-4) extend to the flange of the base (3) to connect with the boiler water system; When multiple sections are connected in parallel, the inlet and outlet of each section of coil pipe first extend radially inward to the corresponding annular space of the header, and then extend axially to the inlet header (2-3) and the outlet header (2). -4); the lengths of the coils of each section are equal or unequal, and the non-complete circles of the coils of each section are added to form a complete circle, so that the interval angles between the inlets or outlets of the coils of each section are completely equal; The inlet and outlet of the coil section are located outside the coil section, which is convenient for welding connection with the header (2). 2-4), at this time, the water inlet pipe (2-31) and the water outlet pipe (2-41) of the coil pipe extend axially to the flange of the base (3). 7. A cylindrical slot type fully premixed water-cooled combustion head structure according to claim 6, characterized in that: the spiral fin coil is a spiral fin straight pipe processed by folding fins along with a cylindrical water cooling The axis of the combustion head is coiled by the helix of the center line; the adjacent helical finned tubes are in contact, and the contact surface is the folded fin surface formed by folding the fins. The area where small smoke flows. 8. A cylindrical slot type fully premixed water-cooled combustion head structure according to claim 6, wherein the oblong or rectangular coil is formed by a straight pipe with an oblong or rectangular cross-section along the The axis of the cylindrical water-cooled combustion head is coiled by the spiral of the center line. The pitch of the spiral is greater than the height of the straight pipe section, forming a spiral gap, and the gap size is 0.2-4mm to improve the flow rate of the premixed gas at the gap. 9. A cylindrical slot type fully premixed water-cooled combustion head structure according to claim 6, characterized in that: when the water-cooled tube bundle (1) is a multi-section spiral fin coil, an oval or a rectangular coil , there will be a spiral gap between the base (3), the top cover (4) and the coil. In order to prevent the premixed gas from leaking from the spiral gap, the spiral refractory material or heat-resistant steel is used to fill the gap.

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