Supersonic nozzle for underground coal gasification

Abstract

The utility model relates to the field of nozzles, in particular to a supersonic nozzle for underground coal gasification, which comprises a nozzle component and a slag scraping component movably connected onto the nozzle component. The nozzle assembly comprises a nozzle shell movably connected to the slag scraping assembly, a sealing groove formed in the outer surface of the nozzle shell, a second compression section, an expansion section, a narrow throat opening formed in one end of the expansion section and a nozzle outlet formed in the other end of the expansion section, wherein the second compression section and the expansion section are connected to the nozzle shell. The threaded pipe is connected to the nozzle shell, the first compression section is connected to the threaded pipe, and the expansion section is connected with the second compression section. The first compression section, the second compression section and the expansion section are of a double-section compression-expansion structure, so that the gas flow speed is further increased to supersonic speed after the throat reaches the sound speed, the mixing efficiency of a gasifying agent and a coal seam is improved, and the gas tightness in an underground high-pressure environment is ensured through threads on the threaded pipe and a sealing groove.

Description

TECHNICAL FIELD

[0001] The utility model relates to a nozzle field especially relates to a kind of supersonic nozzles for coal underground gasification. BACKGROUND

[0002] In order to ignite underground coal seam to start coal underground gasification process, underground coal seam needs to be heated to ignition point in the presence of oxidant such as air, oxygen-enriched air or pure oxygen. The ignition point of various coals such as lignite, bituminous coal, anthracite and coke is generally 400-700℃. When the oxidant is sufficient and the temperature reaches the ignition point, external heating is no longer needed, and the coal seam can maintain the entire combustion / gasification process through its own combustion. Therefore, during the ignition stage of the coal underground gasification process, fuel, heat and oxidant are needed to ignite and sustain the combustion of the underground coal seam, where the coal to be gasified itself can serve as the fuel, the initial heat usually comes from external sources, including the heat generated by the combustion of additional ignition fuel, and the oxidant such as air or oxygen is usually supplied externally.

[0003] In a conventional single-stage nozzle or simple converging-diverging nozzle, the gas flow velocity only reaches the speed of sound at the throat, and the velocity increases limitedly after entering the diverging section, resulting in insufficient turbulence intensity when the gasifying agent contacts the coal seam, and the mixing area is limited to the near-well zone. The distal coal seam is not completely pyrolyzed due to low mass transfer efficiency, affecting the gasification reaction rate and product gas quality. SUMMARY

[0004] To overcome the low mixing efficiency of the existing nozzle during use, which can cause the boundary between the combustion zone and the gasification zone to be blurred, the pyrolysis zone to be enlarged, the invalid pyrolysis reaction to be increased, the carbon conversion rate to be reduced, and more tar and solid residues to be produced due to local oxygen deficiency, blocking the flow passage.

[0005] The technical scheme of the utility model is: a supersonic nozzle for coal underground gasification, comprising a nozzle assembly and a slag scraping assembly movably connected to the nozzle assembly.

[0006] The nozzle assembly comprises a nozzle housing movably connected to the slag scraping assembly, a sealing groove opened on the outer surface of the nozzle housing, a second compression section and an expansion section connected to the nozzle housing, a narrow throat opening at one end of the expansion section, a nozzle outlet opened at the other end of the expansion section, a threaded pipe connected to the nozzle housing, and a first compression section connected to the threaded pipe.

[0007] Preferably, the first compression section is cylindrical, the second compression section and the expansion section are both in the shape of a circular truncated cone, the inlet diameter of the first compression section is D1, the narrow throat diameter of the second compression section is Dt, and the outlet diameter of the expansion section is De, with D1: Dt: De = 50: 12: 13.5.

[0008] Preferably, the length of the first compression section is set as L1, the length of the second compression section is set as L2, and the length of the expansion section is set as L3, and L1:L2:L3=42:64:11.

[0009] Preferably, the pitch of the threads on the threaded pipe is set as P, and the taper of the threads is set as alpha, and P is set as 2mm, and alpha=1:16.

[0010] Preferably, the slag scraping assembly comprises a plurality of slag scraping pieces movably connected to the expansion section, a connecting column connected to the slag scraping pieces, a rotating disc connected to the connecting column, a plurality of fixed strips connected to the rotating disc, a fixed sleeve connected to the rotating disc, and a counterweight connected to the slag scraping pieces.

[0011] Preferably, an eccentric assembly is movably connected to the slag scraping assembly, and the eccentric assembly comprises a sliding rod movably connected to the fixed sleeve, an eccentric rotating disc connected to the sliding rod, an abutting head connected to the eccentric rotating disc, a rotating ring movably connected to the abutting head, a plurality of combination strips connected to the rotating ring, a fixed bolt movably connected to the combination strips, and a combination frame clearance-fitted on the fixed bolt.

[0012] Preferably, a collecting assembly is connected to the eccentric assembly, and the collecting assembly comprises a rotating sleeve connected to the combination frame, a plurality of slag discharging grooves formed in the rotating sleeve, a limiting strip connected to the inner wall of the rotating sleeve, and a collecting cylinder movably connected to the rotating sleeve, and the limiting strip is movably connected to the combination strip.

[0013] The utility model discloses the beneficial effect of:

[0014] 1. The utility model discloses a first compression section, second compression section and expansion section are double -segment compression -expansion structure, make the gas flow rate reach sonic speed after further acceleration to supersonic speed in throat portion, improve the mixing efficiency of gasification agent and coal seam, and through the thread on the threaded pipe and the sealing groove to ensure the air -tightness under the high pressure environment of well.

[0015] 2. In the utility model, when the gasification agent passes through the second compression section, the gas flow will drive the slag scraping piece to rotate around the connecting column, and the coal tar and carbon particles attached to the inner wall are stripped through the rotating slag scraping piece. Through the setting of the counterweight, the slag scraping piece maintains dynamic balance, so that the slag scraping piece can stably rotate along the expansion section to remove carbon deposition. The fixed sleeve rotates to rotate the sliding rod synchronously, so that the sliding rod drives the eccentric rotating disc to rotate along the rotating ring synchronously, so that the eccentric rotating disc produces periodic vibration, and the vibration amplitude is amplified through mechanical resonance to assist the slag scraping piece to strip stubborn carbon deposition.

[0016] 3. The utility model discloses a rotation of the rotating sleeve produces centrifugal force to send the stubborn carbon deposit that the slag scraping piece has stripped to the inside of the rotating sleeve through the centrifugal force, and through the slag discharge groove that sets up on the rotating sleeve to send the stubborn carbon deposit to the collecting cylinder to realize the unified collection to the stubborn carbon deposit. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The utility model discloses a supersonic nozzle structure's three -dimensional structure schematic diagram is shown.

[0018] Figure 2 The utility model discloses a supersonic nozzle structure's first compression subassembly's three -dimensional structure schematic diagram is shown.

[0019] Figure 3 The utility model discloses a supersonic nozzle structure's second compression subassembly's three -dimensional structure schematic diagram is shown.

[0020] Figure 4 The utility model discloses a supersonic nozzle structure's expansion subassembly's three -dimensional structure schematic diagram is shown.

[0021] The utility model discloses a supersonic nozzle structure's three -dimensional structure schematic diagram is shown. DETAILED DESCRIPTION

[0022] The utility model will be further explained below in connection with the drawings and examples.

[0023] A supersonic nozzle for coal underground gasification according to Figures 1-4 As shown in the figure, comprising nozzle assembly 1 and the slag scraping component 2 that moves the connection in nozzle assembly 1;

[0024] The nozzle assembly 1 comprises a nozzle shell 102 movably connected to the slag removing assembly 2, a sealing groove 103 formed on the outer surface of the nozzle shell 102, a second compression section 107 and an expansion section 108 connected to the nozzle shell 102, a narrow throat 104 formed at one end of the expansion section 108, a nozzle outlet 105 formed at the other end of the expansion section 108, a threaded pipe 101 connected to the nozzle shell 102, and a first compression section 106 connected to the threaded pipe 101, and the expansion section 108 is connected to the second compression section 107.

[0025] It should be noted that the first compression section 106, the second compression section 107 and the expansion section 108 are in a double-section compression-expansion structure, so that the gas flow rate is further accelerated to supersonic speed after reaching the sonic speed at the throat, improving the mixing efficiency of the gasifying agent and the coal seam, and the gas tightness in the high-pressure underground environment is ensured by the threads on the threaded pipe 101 and the sealing groove 103, and the critical pressure ratio of the throat is calculated according to the following formula:

[0026]

[0027] When the inlet pressure P0 is 1.89 MPa, the flow rate of the narrow throat 104 reaches the sonic speed M=1, and the expansion section 108 is accelerated to Me≈2.2.

[0028] According to Figure 2 , the first compression section 106 is provided in a cylindrical shape, the second compression section 107 and the expansion section 108 are provided in a circular truncated cone shape, the inlet diameter of the first compression section 106 is D1, the diameter of the narrow throat 104 of the second compression section 107 is Dt, the outlet diameter of the expansion section 108 is De, and D1: Dt: De = 50: 12: 13.5.

[0029] It should be noted that the coiled tubing is connected to the threaded pipe 101, and the inner diameter of the coiled tubing is set as D0=52.4 mm, the diameter of the first compression section 106 is D1=50 mm, the length L1=42 mm, the diameter of the narrow throat 104 of the second compression section 107 is Dt=12 mm, the length L2=64 mm, the half cone angle θ1=15°, the outlet diameter of the expansion section 108 is De=13.5 mm, the length L3=11 mm, and the half cone angle θ2=5°.

[0030] According to Figure 2 , the length of the first compression section 106 is set as L1, the length of the second compression section 107 is set as L2, and the length of the expansion section 108 is set as L3, and L1: L2: L3=42: 64: 11.

[0031] According to Figure 2 , the pitch of the threads on the threaded pipe 101 is set as P, and the taper of the threads is set as α, P is set as 2 mm, and α=1:16.

[0032] According to Figures 3-4 As shown in the drawings, the slag scraping assembly 2 comprises a plurality of slag scraping pieces 201 movably connected to the expansion section 108, a connecting column 202 connected to the slag scraping pieces 201, a rotating disc 203 connected to the connecting column 202, a plurality of fixed strips 204 connected to the rotating disc 203, a fixed sleeve 205 connected to the rotating disc 203, and a counterweight 206 connected to the slag scraping pieces 201.

[0033] It should be noted that when the gasification agent passes through the second compression section 107, the gas flow will drive the slag scraping pieces 201 to rotate around the connecting column 202, and the coal tar and carbon particles attached to the inner wall will be stripped off through the rotating slag scraping pieces 201. Through the setting of the counterweight 206, the slag scraping pieces 201 can maintain dynamic balance, so that the slag scraping pieces 201 can stably rotate along the expansion section 108 to remove the carbon deposits.

[0034] According to Figures 3-4 As shown in the drawings, the slag scraping assembly 2 movably connects an eccentric assembly 3, the eccentric assembly 3 comprises a sliding rod 301 movably connected to the fixed sleeve 205, an eccentric rotating disc 302 connected to the sliding rod 301, an abutting head 303 connected to the eccentric rotating disc 302, a rotating ring 304 movably connected to the abutting head 303, a plurality of combined strips 305 connected to the rotating ring 304, a fixed bolt 306 movably connected to the combined strips 305, and a combined frame 307 clearance fitted on the fixed bolt 306.

[0035] It should be noted that the rotating fixed sleeve 205 synchronously rotates the sliding rod 301, so that the sliding rod 301 synchronously drives the eccentric rotating disc 302 to rotate along the rotating ring 304, so that the eccentric rotating disc 302 produces periodic vibration, and the vibration amplitude is amplified through mechanical resonance, to assist the slag scraping pieces 201 to strip stubborn carbon deposits.

[0036] According to Figure 3 As shown in the drawings, the eccentric assembly 3 is connected with a collection assembly 4, the collection assembly 4 comprises a rotating sleeve 401 connected to the combined frame 307, a plurality of slag discharge grooves 402 opened in the rotating sleeve 401, a limiting strip 403 connected to the inner wall of the rotating sleeve 401, and a collection cylinder 404 movably connected to the rotating sleeve 401, and the limiting strip 403 is movably connected to the combined strips 305.

[0037] It should be noted that the rotation of the rotating sleeve 401 generates centrifugal force, which sends the stubborn carbon deposits stripped by the slag scraping pieces 201 to the inside of the rotating sleeve 401, and through the slag discharge grooves 402 opened in the rotating sleeve 401, the stubborn carbon deposits are sent into the collection cylinder 404, so as to realize the unified collection of the stubborn carbon deposits.

[0038] The embodiment of the utility model has been explained in detail in combination with the drawings, but the utility model is not limited to the above-mentioned embodiment, and various changes can be made within the knowledge range possessed by the person skilled in the art without departing from the purpose of the utility model.

Claims

1. An ultrasonic nozzle for underground coal gasification, characterised in that: The utility model relates to a nozzle assembly (1) and a slag scraping assembly (2) movably connected to the nozzle assembly (1). The nozzle assembly (1) comprises a nozzle shell (102) movably connected to the slag scraping assembly (2), a sealing groove (103) formed on the outer surface of the nozzle shell (102), a second compression section (107) and an expansion section (108) connected to the nozzle shell (102), a narrow throat (104) formed at one end of the expansion section (108), a nozzle outlet (105) formed at the other end of the expansion section (108), a threaded pipe (101) connected to the nozzle shell (102), and a first compression section (106) connected to the threaded pipe (101), wherein the expansion section (108) is connected to the second compression section (107).

2. A supersonic nozzle for underground coal gasification according to claim 1, characterised in that: The first compression section (106) is in the shape of a cylinder, the second compression section (107) and the expansion section (108) are in the shape of a circular truncated cone, the inlet diameter of the first compression section (106) is D1, the diameter of the narrow throat (104) of the second compression section (107) is Dt, the outlet diameter of the expansion section (108) is De, and D1: Dt: De = 50: 12: 13.

5.

3. A supersonic nozzle for underground coal gasification according to claim 1, characterized in that: The length of the first compression section (106) is L1, the length of the second compression section (107) is L2, and the length of the expansion section (108) is L3, and L1: L2: L3 = 42: 64:

11.

4. A supersonic nozzle for underground coal gasification according to claim 1, characterized in that: The pitch of the threads on the threaded pipe (101) is P, and the taper of the threads is α, P is 2 mm, and α = 1:

16.

5. A supersonic nozzle for underground coal gasification according to claim 1, characterized in that: The slag scraping assembly (2) comprises a slag scraping blade (201) movably connected to the expansion section (108), a connecting column (202) connected to the slag scraping blade (201), a rotating disc (203) connected to the connecting column (202), a plurality of fixed strips (204) connected to the rotating disc (203), a fixed sleeve (205) connected to the rotating disc (203), and a counterweight (206) connected to the slag scraping blade (201).

6. A supersonic nozzle for underground coal gasification according to claim 5, characterised in that: The slag scraping assembly (2) movably connects an eccentric assembly (3), the eccentric assembly (3) comprises a sliding rod (301) movably connected to the fixed sleeve (205), an eccentric rotating disc (302) connected to the sliding rod (301), an abutting head (303) connected to the eccentric rotating disc (302), a rotating ring (304) movably connected to the abutting head (303), a plurality of combination strips (305) connected to the rotating ring (304), a fixed bolt (306) movably connected to the combination strips (305), and a combination frame (307) clearance-fitted on the fixed bolt (306).

7. A supersonic nozzle for underground coal gasification according to claim 6, characterised in that: The eccentric assembly (3) is connected to a collecting assembly (4), the collecting assembly (4) comprises a rotating sleeve (401) connected to the combination frame (307), a plurality of slag discharge grooves (402) formed on the rotating sleeve (401), a limiting strip (403) connected to the inner wall of the rotating sleeve (401), and a collecting cylinder (404) movably connected to the rotating sleeve (401), and the limiting strip (403) is movably connected to the combination strips (305).

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