A pulse sootblowing device using Venturi to prevent flashback

Abstract

The invention discloses a pulse sootblower device for preventing backfire by using Venturi, comprising a gas storage tank, a connecting pipe, a backfire preventer, a pressure gauge, a filter, a stop valve, a solenoid valve, a regulating valve, an electromagnetic flowmeter, a Venturi ejector, a damper, a thermometer, an igniter, a tee, an elbow, a combustion sootblower and a blower. The gas storage tank, the backfire preventer, the pressure gauge, the filter, the stop valve, the solenoid valve, the regulating valve, the electromagnetic flowmeter, the Venturi ejector, the damper, the thermometer, the igniter, the combustion sootblower and the blower are connected by connecting pipes, tees and elbows to form a Venturi anti-backfire pulse sootblower system. The built-in baffle of the Venturi ejector can not only strengthen the disturbed mixing of the gas and air, but also separate the flame surface of the reverse propagation. The invention promotes the full mixing of the gas and air, reduces the occurrence of the backfire phenomenon, and significantly improves the safety of the sootblowing process.

Description

Technical Field

[0001] The invention relates to the technical field of power station soot blowing, in particular to a pulse soot blowing device utilizing Venturi to prevent backfire. Background Art

[0002] In the design of power station boilers, effectively removing the ash from the boiler heating surface can significantly improve the heat transfer effect of the heating surface, so it is very important to use soot blowers for soot blowing in the furnace. At present, the commonly used soot blowing equipment is mainly steam soot blowers, sonic soot blowers and gas pulse soot blowers. Due to the characteristics of the structure, working medium and working environment, the steam soot blower is prone to problems such as jamming, failure and steam leakage, the equipment failure rate is high, and the maintenance investment cost is large; the sonic soot blower has problems such as motor burnout and incomplete soot blowing due to the incompatibility between the design energy and the fly ash characteristics of the boiler, which greatly reduces the thermal efficiency of the boiler; the gas pulse soot blower is based on the principle of deflagration of combustible gas, and uses the high-energy impact formed at the moment of deflagration, the accompanying violent sound and the thermal cleaning effect to efficiently clean the ash from the heating surface of the heat exchanger, and effectively solve the problems of adhesion, scaling and blockage between the corrugated plates. Therefore, the gas pulse soot blower with efficient soot blowing capacity has become the preferred equipment for soot blowing in power stations.

[0003] At present, most gas pulse soot blowers installed in power stations use conventional mixing devices to mix gas and air, which cannot achieve full premixing of gas and air. At the same time, the backflow flame propagates upstream during explosion soot blowing, and the flashback phenomenon affects the normal operation of the soot blower. Therefore, a pulse soot blower that uses Venturi to prevent flashback has become one of the key technologies in this field. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a pulse soot blowing device using Venturi to prevent backfire, which can stably, evenly and fully mix fuel gas and air, effectively separate the backflow flame surface during pulse soot blowing, and reduce the occurrence of flame propagation upstream.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0006] A pulse sootblowing device for preventing backfire by using Venturi, comprising a gas storage tank 1, a connecting pipe a2, a backfire preventer 3, a pressure gauge a4, a connecting pipe b5, a filter 6, a stop valve 7, a connecting pipe c8, a solenoid valve a9, a connecting pipe d10, a regulating valve 11, a connecting pipe e12, a pressure gauge b13, a connecting pipe f14, an electromagnetic flowmeter a15, a connecting pipe g16, a Venturi ejector 17, a connecting pipe h18, a damper 19, a connecting pipe i20, a temperature gauge 21, an ignition Device 22, tee 23, connecting pipe j24, elbow a25, connecting pipe k26, elbow b27, combustion soot blower a28, connecting pipe l29, elbow c30, connecting pipe m31, elbow d32, combustion soot blower b33, connecting pipe n34, elbow e35, connecting pipe o36, electromagnetic flowmeter c37, connecting pipe p38, solenoid valve b39, connecting pipe q40, elbow f41, connecting pipe r42, elbow g43, connecting pipe s44 and air blower 45.

[0007] The outlet of the gas storage tank 1, the connecting pipe a2, the pressure gauge a4, the connecting pipe b5, the filter 6, the stop valve 7, the connecting pipe c8, the solenoid valve a9, the connecting pipe d10, the regulating valve 11, the connecting pipe e12, the pressure gauge b13, the connecting pipe f14, the electromagnetic flowmeter a15, the connecting pipe g16 and the injection port of the venturi injector 17 are connected in sequence through flanges to form a gas supply branch.

[0008] The air supply port of the blower 45, the connecting pipe s44, the elbow g43, the connecting pipe r42, the elbow f41, the connecting pipe q40, the solenoid valve b39, the connecting pipe p38, the electromagnetic flowmeter c37, the connecting pipe o36, the elbow e35, the connecting pipe n34 and the inlet of the venturi ejector 17 are connected in sequence through flanges to form an air supply branch.

[0009] The outlet of the venturi ejector 17, the connecting pipe h18, the damper 19, the connecting pipe i20, the thermometer 21, the igniter 22 and the inlet of the tee 23 are connected in sequence through flanges, the left outlet of the tee 23, the connecting pipe j24, the elbow a25, the connecting pipe k26, the elbow b27 and the combustion soot blower a28 are connected in sequence through flanges, and the right outlet of the tee 23, the connecting pipe l29, the elbow c30, the connecting pipe m31, the elbow d32 and the combustion soot blower b33 are connected in sequence through flanges to form a mixed combustion main circuit.

[0010] The venturi ejector 17 comprises a contraction section 171 with a contraction angle of 32°, a throat 172, a diffusion section 173 with a diffusion angle of 18° and an ejection hole 174. The internal radial cross-section is circular, and the diameter of the throat 172 is d. A cylindrical ejection hole 174 is arranged on the side of the throat 172 of the venturi ejector 17, which is connected to the inner cavity of the throat 172.

[0011] The inner wall of the diffuser section 173 of the venturi ejector 17 is provided with semicircular baffles a1731, baffles b1732, baffles c1733, baffles d1734, baffles e1735 and baffles f1736 in sequence along the axial direction; the baffles are arranged in an upper and lower staggered manner, baffle a1731 is provided at the lower part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 1.5d, baffle b1732 is provided at the upper part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 2.5d, baffle c1733 is provided at the upper part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 2.5d, baffle c1734 is provided at the lower part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 2.5d, baffle e1735 is provided at the lower part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 2.5d, baffle e1736 is provided at the upper part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 2.5d, baffle e1736 is provided at the lower part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 2.5d, baffle e1736 is provided at the upper part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 2.5d, baffle e1737 is provided at the upper part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 2.5d, 1733 is arranged at the lower part of the diffuser section 173, and is 3.5d away from the outlet of the throat 172 in the axial direction. The baffle d1734 is arranged at the upper part of the diffuser section 173, and is 4.5d away from the outlet of the throat 172 in the axial direction. The baffle e1735 is arranged at the lower part of the diffuser section 173, and is 5.5d away from the outlet of the throat 172 in the axial direction. The baffle f1736 is arranged at the upper part of the diffuser section 173, and is 6.5d away from the outlet of the throat 172 in the axial direction. The thickness of each baffle is 0.2d, and the angle with the axial direction is 45°.

[0012] The beneficial effects of the present invention are:

[0013] The present invention discloses a pulse sootblowing device which utilizes Venturi to prevent backfire. Compared with a conventional gas pulse sootblower, a Venturi ejector with a diffusion section provided with a baffle of a specific structure is used as a mixer for gas and air, which not only realizes sufficient disturbance mixing of gas and air before combustion and sootblowing, but also utilizes air to eject gas, thereby reducing the pressure required on the gas side; and by arranging staggered baffles in the diffusion section of the Venturi ejector, the propagation of the reverse backflow flame surface is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a left isometric view of a pulse sootblowing device for preventing flashback by using Venturi according to the present invention;

[0015] Figure 2 It is a right isometric view of a pulse sootblowing device for preventing flashback by using Venturi according to the present invention;

[0016] Figure 3 A three-dimensional view of a tee of a pulse sootblowing device using Venturi to prevent flashback according to the present invention;

[0017] Figure 4 A three-dimensional view of a venturi ejector of a pulse sootblowing device utilizing venturi to prevent flashback according to the present invention;

[0018] Figure 5 It is a left view, a first front view (Venturi ejector cross section) and a second front view (Venturi ejector cross section) of a venturi ejector of a pulse sootblowing device utilizing venturi to prevent flashback according to the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0020] The present invention discloses a pulse sootblowing device for preventing backfire by using Venturi, comprising a gas storage tank 1, a connecting pipe a2, a backfire preventer 3, a pressure gauge a4, a connecting pipe b5, a filter 6, a stop valve 7, a connecting pipe c8, an electromagnetic valve a9, a connecting pipe d10, a regulating valve 11, a connecting pipe e12, a pressure gauge b13, a connecting pipe f14, an electromagnetic flowmeter a15, a connecting pipe g16, a Venturi ejector 17, a connecting pipe h18, a damper 19, a connecting pipe i20, a thermometer 21, an igniter 22, a tee 23, a connecting pipe j24, an elbow a25, a connecting pipe k26, an elbow b27, a combustion sootblower a28, a connecting pipe Pipeline L29, elbow C30, connecting pipe M31, elbow D32, combustion soot blower B33, connecting pipe N34, elbow E35, connecting pipe O36, electromagnetic flowmeter C37, connecting pipe P38, solenoid valve B39, connecting pipe Q40, elbow F41, connecting pipe R42, elbow G43, connecting pipe S44 and air blower 45; Venturi ejector 17 includes contraction section 171, throat 172, diffusion section 173 and ejection hole 174, and diffusion section 173 includes baffle A1731, baffle B1732, baffle C1733, baffle D1734, baffle E1735 and baffle F1736.

[0021] Reference Figure 1 and Figure 2The outlet of the gas storage tank 1, the connecting pipe a2, the pressure gauge a4, the connecting pipe b5, the filter 6, the stop valve 7, the connecting pipe c8, the electromagnetic valve a9, the connecting pipe d10, the regulating valve 11, the connecting pipe e12, the pressure gauge b13, the connecting pipe f14, the electromagnetic flowmeter a15, the connecting pipe g16 and the ejection port of the venturi ejector 17 are connected in sequence through flanges to form a gas supply branch. The air supply port of the blower 45, the connecting pipe s44, the elbow g43, the connecting pipe r42, the elbow f41, the connecting pipe q40, the electromagnetic valve b39, the connecting pipe p38, the electromagnetic flowmeter c37, the connecting pipe o36, the elbow e35, the connecting pipe n34 and the inlet of the venturi ejector 17 are connected in sequence through flanges to form an air supply branch. The outlet of the venturi ejector 17, the connecting pipe h18, the damper 19, the connecting pipe i20, the thermometer 21, the igniter 22, and the inlet of the tee 23 are connected by flanges in sequence. The left outlet of the tee 23, the connecting pipe j24, the elbow a25, the connecting pipe k26, the elbow b27 and the combustion soot blower a28 are connected by flanges in sequence. The right outlet of the tee 23, the connecting pipe l29, the elbow c30, the connecting pipe m31, the elbow d32 and the combustion soot blower b33 are connected by flanges in sequence, and the whole constitutes a mixed combustion main circuit. The above-mentioned gas supply branch, air supply branch and mixed combustion main circuit together constitute the entire venturi premixed pulse soot blower system. All elbows in the soot blower system are stainless steel right-angle elbows, and all components are connected by disc-shaped flanges with flexible sealing pads. The flashback preventer 3 is installed on the connecting pipe a2 to prevent flashback during pulse soot blowing from entering the gas storage tank 1.

[0022] As a preferred embodiment of the present invention, Figure 1 and Figure 2As shown, the gas from the gas storage tank 1 flows into the connecting pipe a2 through the outlet, and then flows through the backfire arrester 3, the pressure gauge a4, the connecting pipe b5, the filter 6, the stop valve 7, the connecting pipe c8, the solenoid valve a9, the connecting pipe d10, the regulating valve 11, the connecting pipe e12, the pressure gauge b13, the connecting pipe f14, the electromagnetic flowmeter a15 and the connecting pipe g16 in sequence, and then flows into the Venturi from the ejection port of the Venturi ejector 17. The air flows from the air supply port of the blower 45 in sequence through the connecting pipe s44, the elbow g43, the connecting pipe r42, the elbow f41, the connecting pipe q40, the solenoid valve b39, the connecting pipe p38, the electromagnetic flowmeter c37, the connecting pipe o36, the elbow e35 and the connecting pipe n34, and then flows into the Venturi from the inlet of the Venturi ejector 17. The air flowing into the Venturi ejector 17 from the inlet flows to the throat 172, ejecting the gas flowing in from the ejection port. The two are fully mixed to form a gas-air mixture, which flows out through the outlet of the Venturi ejector 17 as the gas source of the pulse soot blower, and then flows through the connecting pipe h18, damper 19, connecting pipe i20, thermometer 21, igniter 22 and the inlet of the tee 23 in sequence. Then part of the mixed gas is diverted from the left outlet of the tee 23, flows through the connecting pipe j24, elbow a25, connecting pipe k26 and elbow b27 in sequence, and finally enters the combustion soot blower a28. Another part of the mixed gas is diverted from the right outlet of the tee 23, flows through the connecting pipe l29, elbow c30, connecting pipe m31 and elbow d32 in sequence, and finally enters the combustion soot blower b33. The igniter 22 is used as an ignition source to ignite the mixed gas in the mixed combustion main circuit to perform pulse soot blowing in the furnace.

[0023] like Figure 3 As shown, the port near the large wireframe arrow is the inlet of the tee 23 , the port near the small wireframe arrow on the left is the left outlet of the tee 23 , and the port near the small wireframe arrow on the right is the right outlet of the tee 23 .

[0024] like Figure 4As shown, the venturi ejector 17 includes a contraction section 171, a throat 172, a diffusion section 173 and an ejection hole 174, and the internal radial cross-section is circular. A cylindrical ejection hole 174 is opened on the side of the throat 172 of the venturi ejector 17 and is connected to the inner cavity of the throat 172. The port near the small wireframe arrow is the entrance of the ejection hole 174 of the Venturi ejector 17, the port near the medium wireframe arrow is the entrance of the Venturi ejector 17, and the port near the large wireframe arrow is the outlet of the Venturi ejector 17. Air flows in from the entrance of the Venturi ejector 17. As the flow cross-section of the contraction section 171 decreases, the air velocity increases, and the velocity reaches a maximum when it flows to the throat 172, forming a low-pressure area. The Venturi effect is used to eject the combustion gas flowing into the entrance of the ejection hole 174. The two are mixed in the throat 172 and then enter the diffusion section 173. After being fully mixed, they enter the mixed combustion main circuit through the outlet of the Venturi ejector 17 as a sootblowing gas source.

[0025] Figure 5 The left image is a left view of the Venturi ejector 17, the middle image is a first cross-sectional view of the Venturi ejector 17, and the right image is a second cross-sectional view of the Venturi ejector 17, and the cross-sectional position is marked in the left view.

[0026] Referring to the first cross-sectional view, the contraction angle of the contraction section 171 of the venturi ejector 17 is 32°, the diffusion angle of the diffusion section 173 is 18°, the diameter of the throat 172 is d, and a plurality of semicircular baffles are arranged in sequence along the axial direction on the inner wall of the diffusion section 173 of the venturi ejector 17, and the circular surface of each baffle forms an angle of 45° with the axis of the diffusion section 173. Along the axis direction of the diffusion section 173, the baffles are staggered up and down at equal intervals, and the terminal plane coincides with the axis.

[0027] After numerical simulation of the flow field distribution inside the diffuser 173, the arrangement of the baffles is optimized. The detailed parameters of the example are given as follows, that is, the baffles are arranged up and down in the diffuser 173 of the venturi ejector 17, the diameter of the throat 172 is d (preferably 8.5 cm in this patent), the baffle a1731 is arranged at the lower part of the diffuser 173, and the axial distance from the outlet of the throat 172 is 12.75 cm (1.5 d), the baffle b1732 is arranged at the upper part of the diffuser 173, and the axial distance from the outlet of the throat 172 is 21.25 cm (2.5 d), and the baffle c1733 is arranged at the lower part of the diffuser 173. The axial distance from the outlet of the throat 172 is 29.75 cm (3.5 d), the baffle d1734 is arranged at the upper part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 38.25 cm (4.5 d), the baffle e1735 is arranged at the lower part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 46.75 cm (5.5 d), the baffle f1736 is arranged at the upper part of the diffuser section 173, and the axial distance from the outlet of the throat 172 is 55.25 cm (6.5 d), and the axial length l of the diffuser section 173 is 59.5 cm (7 d), which should actually be ensured to be at least greater than 6.5 d.

[0028] The mainstream air and the injected gas are divided into upper and lower layers at the throat 172 outlet. The baffle arrangement method in the above example is adopted, so that the gas originally located in the lower layer after injection first shears the air flow layer upward along the baffle a1731, increases the radial velocity of the gas flow, strengthens the disturbance between the gas and air layers, and improves the uniformity of gas and air mixing; the air located in the upper layer after injection then shears the gas flow layer downward along the baffle b1732, further strengthening the uniform mixing of the gas and air, and repeats the disturbance up and down and mixes evenly until it flows through the baffle f1736 and enters the mixed combustion main path from the outlet of the diffusion section 173.

[0029] Adding the baffle with the above-mentioned specific structure to a specific position in the diffusion section 173 of the venturi ejector 17 can not only strengthen the disturbance of the gas and air in the diffusion section 173 of the venturi ejector 17 and improve the uniformity of the mixed gas at the outlet of the venturi ejector 17, but also prevent the backflow flame from propagating upstream when the combustion soot blower is ignited, and separate the backflow flame to the near-wall boundary area in the diffusion section 173 of the venturi ejector 17. In the first sectional view, the wavy wireframe arrow shows the supply direction of the gas and air mixture. The two are disturbed up and down and fully mixed under the action of the baffle, and then enter the mixed combustion main circuit as the soot blowing gas source. In the second sectional view, the wavy wireframe arrow shows the reverse propagation process of the combustion flame surface during explosion soot blowing. The baffle separates the flame surface to the edge area close to the inner wall of the diffusion section 173, inhibiting the flame surface from further propagating upstream, effectively preventing the occurrence of backfire.

[0030] In summary, the present invention uses a venturi ejector with a special structure baffle arranged in the diffusion section as a mixer for gas and air, so that the gas and air are disturbed interactively and fully mixed; by adding a special structure and a baffle at a specific position in the diffusion section of the venturi ejector, the explosion soot blowing backflow flame surface is separated to the near-wall boundary area, thereby suppressing the occurrence of backfire.

Claims

1. A pulse sootblowing device using Venturi to prevent flashback, Features: The invention comprises a gas storage tank (1), a connecting pipe a (2), a backfire preventer (3), a pressure gauge a (4), a connecting pipe b (5), a filter (6), a stop valve (7), a connecting pipe c (8), an electromagnetic valve a (9), a connecting pipe d (10), a regulating valve (11), a connecting pipe e (12), a pressure gauge b (13), a connecting pipe f (14), an electromagnetic flowmeter a (15), a connecting pipe g (16) and a venturi ejector (17) which are connected in sequence; the venturi ejector (17), a connecting pipe h (18), a damper (19), a connecting pipe i (20), a temperature gauge (21), an igniter (22), a tee (23), a connecting pipe j ( 24), elbow a (25), connecting pipe k (26), elbow b (27) and combustion soot blower a (28) are connected in sequence; tee (23), connecting pipe l (29), elbow c (30), connecting pipe m (31), elbow d (32) and combustion soot blower b (33) are connected in sequence; venturi ejector (17), connecting pipe n (34), elbow e (35), connecting pipe o (36), electromagnetic flowmeter c (37), connecting pipe p (38), electromagnetic valve b (39), connecting pipe q (40), elbow f (41), connecting pipe r (42), elbow g (43), connecting pipe s (44) and blower (45) are connected in sequence The venturi ejector (17) comprises a contraction section (171), a throat (172), a diffusion section (173) and an ejection hole (174); the inner wall of the diffusion section (173) of the venturi ejector (17) is provided with a semicircular baffle a (1731), a baffle b (1732), a baffle c (1733), a baffle d (1734), a baffle e (1735) and a baffle f (1736) in sequence along the axial direction; the baffles are arranged in an upper and lower staggered manner, the baffle a (1731) is provided at the lower part of the diffusion section (173) and is 1.5d away from the outlet of the throat (172) in the axial direction, and the baffle b (1732) is provided at the lower part of the diffusion section (173) and is 1.5d away from the outlet of the throat (172) in the axial direction. The baffle plate c (1733) is arranged at the lower part of the diffusion section (173), at an axial distance of 3.5 d from the outlet of the throat (172); the baffle plate d (1734) is arranged at the upper part of the diffusion section (173), at an axial distance of 4.5 d from the outlet of the throat (172); the baffle plate e (1735) is arranged at the lower part of the diffusion section (173), at an axial distance of 5.5 d from the outlet of the throat (172); the baffle plate f (1736) is arranged at the upper part of the diffusion section (173), at an axial distance of 6.5 d from the outlet of the throat (172); the thickness of each baffle plate is 0.2 d, and the angle between each baffle plate and the axial direction is 45°.

2. A pulse sootblowing device using Venturi to prevent flashback according to claim 1, Features: The outlet of the gas storage tank (1), the connecting pipe a (2), the pressure gauge a (4), the connecting pipe b (5), the filter (6), the stop valve (7), the connecting pipe c (8), the electromagnetic valve a (9), the connecting pipe d (10), the regulating valve (11), the connecting pipe e (12), the pressure gauge b (13), the connecting pipe f (14), the electromagnetic flowmeter a (15), the connecting pipe g (16) and the ejection port of the venturi ejector (17) are connected in sequence through flanges to form a gas supply branch.

3. A pulse sootblowing device using Venturi to prevent flashback according to claim 1, Features: The air supply port of the blower (45), the connecting pipe s (44), the elbow g (43), the connecting pipe r (42), the elbow f (41), the connecting pipe q (40), the electromagnetic valve b (39), the connecting pipe p (38), the electromagnetic flowmeter c (37), the connecting pipe o (36), the elbow e (35), the connecting pipe n (34) and the inlet of the venturi ejector (17) are connected in sequence through flanges to form an air supply branch.

4. A pulse sootblowing device using Venturi to prevent flashback according to claim 1, Features: The outlet of the venturi ejector (17), the connecting pipe h (18), the damper (19), the connecting pipe i (20), the temperature gauge (21), the igniter (22) and the inlet of the tee (23) are connected in sequence through flanges; the left outlet of the tee (23), the connecting pipe j (24), the elbow a (25), the connecting pipe k (26), the elbow b (27) and the combustion soot blower a (28) are connected in sequence through flanges; the right outlet of the tee (23), the connecting pipe l (29), the elbow c (30), the connecting pipe m (31), the elbow d (32) and the combustion soot blower b (33) are connected in sequence through flanges to form a mixed combustion main circuit.

5. A pulse sootblowing device using Venturi to prevent flashback according to claim 1, Features: The contraction angle of the contraction section (171) of the Venturi ejector (17) is 32°, and the diffusion angle of the diffusion section (173) is 18°; the inner radial cross section of the Venturi ejector (17) is circular, and a cylindrical ejection hole (174) is provided on the side of the throat (172) of the Venturi ejector (17) and is communicated with the inner cavity of the throat (172).

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