Gas heater for heating wellhead of oil field

Abstract

The gas heater comprises a shell, a combustion chamber is arranged in the shell, a heating chamber located above the combustion chamber is arranged on the shell, the inner wall of the shell and the outer wall of the combustion chamber form a heat exchange cavity, the heat exchange cavity is communicated with the heating chamber, the side wall of the shell is communicated with an oil conveying pipe, and the two ends of the oil conveying pipe are located outside the shell. The side wall of the combustion chamber is provided with a burner, the side wall of the shell is provided with a slag discharge pipe communicated with the combustion chamber, the side, away from the burner, of the combustion chamber is provided with an ash scraping assembly, and one side of the combustion chamber is provided with a purification assembly. The heat exchange cavity is filled with a liquid medium, the inner wall of the combustion cavity is heated through fire spraying of the burner, the liquid medium is vaporized and enters the heating cavity, the temperature in the heating cavity is increased, crude oil in the oil conveying pipe passing through the heating cavity is heated, and impurities and dust on the inner wall of the combustion cavity are cleaned through the dust scraping assembly.

Description

Technical Field

[0001] This application relates to the technical field of heat exchange, and particularly to a gas heater for heating oil wells at the oilfield wellhead. Background Art

[0002] Crude oil exists in a solid or highly viscous state underground. Heating can significantly reduce its viscosity and enhance its fluidity. When crude oil is extracted to the ground, in order to meet the gathering and transportation requirements of oil production wells far from the centralized treatment station, oilfield companies have installed heating furnaces or heaters at the wellhead to heat the crude oil, reduce the viscosity of the crude oil, overcome the problems of long distance and excessive flow resistance, so as to meet the gathering and transportation requirements and ensure the smooth pipeline transportation.

[0003] During the combustion process of the burner, various impurities and dust often accumulate on the furnace wall of the combustion chamber. If not cleaned for a long time, slag will form on the furnace wall, affecting heat transfer, resulting in insufficient heating temperature of the connection chamber and affecting the heating of the oil. Summary of the Invention

[0004] In order to facilitate the cleaning of impurities and dust accumulated on the inner wall of the combustion chamber, this application provides a gas heater for heating oil wells at the oilfield wellhead.

[0005] This application provides a gas heater for heating oil wells at the oilfield wellhead, adopting the following technical solutions: A gas heater for heating oil wells at the oilfield wellhead includes a housing. A combustion chamber is arranged inside the housing. A heating chamber is arranged above the combustion chamber on the housing. A heat exchange chamber is formed between the inner wall of the housing and the outer wall of the combustion chamber. The heat exchange chamber is communicated with the heating chamber. A fuel pipe is communicated with the side wall of the housing. Both ends of the fuel pipe are located outside the housing. The fuel pipe is arranged in a serpentine shape inside the heating chamber. A burner is arranged on the side wall of the combustion chamber. A slag discharge pipe communicated with the combustion chamber is arranged on the side wall of the housing. A dust scraping assembly is arranged on the side of the combustion chamber away from the burner. A purification assembly is arranged on one side of the combustion chamber.

[0006] By adopting the above technical solutions, a liquid medium is filled in the heat exchange chamber. The inner wall of the combustion chamber is heated by the burner spraying fire, so that the liquid medium vaporizes and enters the heating chamber, increasing the temperature in the heating chamber, heating the crude oil in the fuel pipe passing through the heating chamber, and cleaning the impurities and dust on the inner wall of the combustion chamber through the dust scraping assembly.

[0007] Optionally, the ash scraping assembly includes a sealed box fixedly installed on the side wall of the combustion chamber. A connection box body is provided at one end of the sealed box away from the combustion chamber. A heat conduction pipe is connected between the combustion chamber and the connection box body. A first control valve is installed on the heat conduction pipe. An elastic spring is provided on the inner wall of the sealed box close to the connection box body. The end of the elastic spring is connected to a first piston plate. The first piston plate fits against the inner wall of the sealed box and is slidably connected to the sealed box. A connecting rod is provided on the side wall of the first piston plate. One end of the connecting rod away from the first piston plate passes through the sealed box and the combustion chamber in sequence and is fixedly connected to a fixing plate located in the combustion chamber. A scraper is fixedly provided on the fixing plate, and the outer wall of the scraper abuts against the inner wall of the combustion chamber.

[0008] By adopting the above technical solution, the hot air in the heating chamber enters the connection box body through the heat conduction pipe, the temperature in the connection box body rises, the temperature of the air inside the first piston plate close to the elastic spring rises, the air expands due to the temperature rise, and the first piston plate is pushed to move towards the combustion chamber direction, thereby driving the connecting rod to move. Through the fixing plate, the scraper moves in the combustion chamber to clean the impurities and dust on the inner wall of the combustion chamber.

[0009] Optionally, a second piston plate is slidably connected in the sealed box. The outer wall of the second piston plate fits against the inner wall of the sealed box. The connecting rod passes through the second piston plate and is movably connected to the second piston plate. The first piston plate and the second piston plate divide the sealed box into a first chamber, a second chamber and a third chamber from the direction close to the connection box body to the direction away from the connection box body. Sliding grooves are symmetrically formed on both sides of the first piston plate and the second piston plate close to each other. A slider is slidably connected inside each sliding groove. A first rotating rod is rotatably connected to the side wall of the slider on the first piston plate, and a second rotating rod is rotatably connected to the side wall of the slider on the second piston plate. The hinged part of the first rotating rod and the second rotating rod is rotatably connected to the inner wall of the sealed box.

[0010] By adopting the above technical solution, during the movement of the first piston plate towards the combustion chamber direction, the elastic spring is in a stretched state, applying a pulling force towards the installation box direction to the first piston plate. At the same time, the first rotating rod rotates. The hinged part of the first rotating rod and the second rotating rod is connected by two meshing gears. During the rotation of the first rotating rod, the second rotating rod rotates along with the first rotating rod, causing the second piston plate to move towards the first piston plate direction.

[0011] Optionally, air storage boxes are arranged on both the upper and lower sides of the sealed box. Connecting springs are arranged on the inner walls of the two air storage boxes. Sealing plates are arranged at the ends of the connecting springs. The outer walls of the sealing plates are in contact with the inner walls of the air storage boxes and are slidably connected to the air storage boxes. Air inlet pipes communicating with the third chamber are arranged at both the upper and lower ends on one side of the sealed box. One ends of the air inlet pipes are communicated with the adjacent air storage boxes; one-way air inlet valves are installed on the air inlet pipes. The one-way air inlet valves allow the gas in the third chamber of the sealed box to enter the air storage boxes. Air delivery pipes communicating with the first chamber are arranged at both the upper and lower ends of the sealed box. One-way air delivery valves are arranged on the air delivery pipes. The one-way air delivery valves allow the gas in the air storage boxes to enter the first chamber in the sealed box.

[0012] By adopting the above technical solution, when the force generated by the pressure difference between the first chamber and the second chamber is less than the pulling force of the elastic spring on the first piston plate, the first piston plate is driven to move away from the combustion chamber. During the process of driving the connecting rod to move, the second piston plate is driven to move away from the first piston plate through the first rotating rod and the second rotating rod. The pressure in the third chamber increases, so that the normal-temperature gas in the third chamber enters the air storage box along the air inlet pipe, causing the sealing plate to move and compressing the connecting spring, and opening the one-way air delivery valve. Under the action of the connecting spring, the gas in the air storage box enters the first chamber through the air delivery pipe. By continuously heating and expanding, the first piston plate is pushed to move. While the first piston plate reciprocates in the sealed box, the scraper is driven to reciprocate in the combustion chamber through the connecting rod.

[0013] Optionally, an air suction pipe communicating with the third chamber is arranged on the sealed box. A one-way air suction valve is installed on the air suction pipe. An air discharge pipe communicating with the first chamber is arranged on the sealed box. An electromagnetic valve is installed on the air discharge pipe. A pressure relief hole communicating with the second chamber is opened on the sealed box.

[0014] By adopting the above technical solution, when the first piston plate moves to the limit towards the combustion chamber, the electromagnetic valve is opened, and the first chamber communicates with the outside through the air discharge pipe. The force generated by the pressure difference between the first chamber and the second chamber is less than the pulling force of the elastic spring on the first piston plate, driving the first piston plate 22 to move away from the combustion chamber.

[0015] Optionally, the purification assembly includes a first connecting pipe, a purification box, and a second connecting pipe. The first connecting pipe and the second connecting pipe are respectively communicated with the purification box. The other end of the first connecting pipe is communicated with the connecting box body. The other end of the second connecting pipe is communicated with the combustion chamber.

[0016] By adopting the above technical solution, the high-temperature gas contained in the connecting box body enters the purification box along the first connecting pipe. Iron oxide is installed in the purification box. Iron oxide undergoes an oxidation reaction with CO to oxidize CO, and the reaction generates CO2, reducing the generation of CO and reducing air pollution.

[0017] Optionally, a first one-way valve is provided on the first connecting pipe, and the first one-way valve allows gas to enter the purification tank from the connection box body. A second one-way valve is installed on the second connecting pipe, and the second one-way valve allows the gas in the purification tank to enter the combustion chamber.

[0018] By adopting the above technical solution, the on-off of the first connecting pipe and the second connecting pipe is controlled by the first one-way valve and the second one-way valve.

[0019] Optionally, two partition plates are provided in the purification tank. A number of round holes are opened on both partition plates. A feeding pipe located between the two partition plates is communicated with the top of the purification tank. A discharging pipe located below the feeding pipe is provided at the bottom of the purification tank. Sealing covers are provided on both the feeding pipe and the discharging pipe.

[0020] By adopting the above technical solution, when the high-temperature gas containing CO passes through the partition plate with round holes, the high-temperature gas is dispersed, so that CO is in full contact with the iron oxide in the purification tank, increasing the reaction efficiency.

[0021] In summary, the present application includes at least one of the following beneficial technical effects: The heat exchange cavity is filled with a liquid medium. The inner wall of the combustion chamber is heated by the burner spraying fire, so that the liquid medium vaporizes and enters the heating cavity, increasing the temperature in the heating cavity, and heating the crude oil in the oil pipeline passing through the heating cavity. By opening the first control valve, the high-temperature gas in the combustion chamber enters the connection box body along the heat conduction pipe. The high temperature in the connection box body heats the gas in the sealed box, pushing the first piston plate to move, so that the scraper moves in the combustion chamber, and timely scrapes the slag blocks on the inner wall of the combustion chamber, facilitating the cleaning of the impurities and dust accumulated on the inner wall of the combustion chamber. The impurities falling in the combustion chamber are discharged through the slag discharge pipe. The purification tank is filled with iron oxide. Open the first control valve, and the high-temperature gas containing CO in the combustion chamber enters the connection box body along the heat conduction pipe. Open the first one-way valve, and the high-temperature gas containing CO in the connection box body enters the purification tank along the first connecting pipe. CO is in full contact with the iron oxide in the purification tank and undergoes an oxidation reaction to oxidize CO, and the reaction generates CO 2 Open the second one-way valve to make CO 2 enter the combustion chamber along the second connecting pipe, avoiding the leakage of CO into the air. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the overall structural schematic diagram of Embodiment 1 of the present application.

[0023] Figure 2It is a schematic diagram showing the internal structure of the housing in Embodiment 1 of the present application.

[0024] Figure 3 It is a schematic diagram showing the internal structure of the sealed box in Embodiment 1 of the present application.

[0025] Figure 4 It is a schematic diagram showing the structure of the purification component in Embodiment 2 of the present application.

[0026] Figure 5 It is a schematic diagram showing the internal structure of the purification box in Embodiment 2 of the present application.

[0027] Explanation of reference numerals: 1. Housing; 11. Combustion chamber; 12. Heating chamber; 13. Heat exchange chamber; 14. Oil pipeline; 15. Burner; 16. Slag discharge pipe; 17. Smoke exhaust pipe; 171. Ventilation pipe; 2. Sealed box; 21. Elastic spring; 22. First piston plate; 23. Second piston plate; 24. Slide block; 25. First rotating rod; 26. Second rotating rod; 27. Suction pipe; 271. One-way suction valve; 28. Air release pipe; 281. Solenoid valve; 29. Pressure relief hole; 3. Connection box body; 31. Heat conduction pipe; 32. First control valve; 4. Connecting rod; 41. Fixed plate; 42. Scraper; 5. Gas storage box; 51. Connecting spring; 52. Sealing plate; 53. Air inlet pipe; 531. One-way air inlet valve; 54. Gas pipeline; 541. One-way gas transmission valve; 6. Purification component; 61. First connecting pipe; 62. Purification box; 621. Feeding pipe; 622. Discharge pipe; 6221. Sealing cover; 63. Second connecting pipe; 64. First one-way valve; 65. Second one-way valve; 66. Partition plate; 661. Round hole. Detailed implementation manners

[0028] The following further elaborates on the present application in conjunction with all the drawings. Embodiment 1

[0029] Embodiment 1 of the present application discloses a gas heater for heating at an oilfield wellhead.

[0030] Refer to Figure 1 and Figure 2, A gas heater for heating oil wellheads in oil fields, comprising a housing 1. A combustion chamber 11 is arranged inside the housing 1. A heating chamber 12 is arranged on the housing 1 above the combustion chamber 11. A heat exchange chamber 13 is formed between the inner wall of the housing 1 and the outer wall of the combustion chamber 11. The heat exchange chamber 13 is communicated with the heating chamber 12. A fuel pipeline 14 is communicated with the side wall of the housing 1. Both ends of the fuel pipeline 14 are located outside the housing 1. The fuel pipeline 14 is arranged in a serpentine shape inside the heating chamber 12. A burner 15 is arranged on the side wall of the combustion chamber 11. A gas supply device for supplying gas to the burner 15 is arranged on one side of the combustion chamber 11. A liquid medium is filled in the heat exchange chamber 13. The inner wall of the combustion chamber 11 is heated by the burner 15 spraying fire, so that the liquid medium vaporizes and enters the heating chamber 12, increasing the temperature in the heating chamber 12, heating the crude oil in the fuel pipeline 14 passing through the heating chamber 12, reducing the viscosity of the crude oil, and enhancing the fluidity of the crude oil.

[0031] Refer to Figure 2 and Figure 3 , A dust scraping assembly is arranged on the side of the combustion chamber 11 away from the burner 15. The dust scraping assembly includes a sealing box 2. The sealing box 2 is fixedly installed on the side wall of the combustion chamber 11. A connecting box body 3 is arranged at one end of the sealing box 2 away from the combustion chamber 11. A heat conduction pipe 31 is communicated between the combustion chamber 11 and the connecting box body 3. A first control valve 32 is installed on the heat conduction pipe 31. An elastic spring 21 is arranged on the inner wall of the sealing box 2 close to the connecting box body 3. The end of the elastic spring 21 is connected with a first piston plate 22. The first piston plate 22 fits with the inner wall of the sealing box 2 and is slidably connected with the sealing box 2. A second piston plate 23 is slidably connected in the sealing box 2. The outer wall of the second piston plate 23 fits with the inner wall of the sealing box 2. A connecting rod 4 is arranged on the side wall of the first piston plate 22. One end of the connecting rod 4 away from the first piston plate 22 passes through the second piston plate 23, the sealing box 2, and the combustion chamber 11 in sequence and is fixedly connected with a fixing plate 41 located inside the combustion chamber 11. A scraping plate 42 is fixedly arranged on the fixing plate 41. The outer wall of the scraping plate 42 abuts against the inner wall of the combustion chamber 11.

[0032] On both the upper and lower sides of the sealed box 2, air storage boxes 5 are provided. On the inner walls of the two air storage boxes 5, connecting springs 51 are provided. At the end of the connecting spring 51, a sealing plate 52 is provided. The outer wall of the sealing plate 52 fits against the inner wall of the air storage box 5 and is slidably connected to the air storage box 5. The first piston plate 22 and the second piston plate 23 divide the sealed box 2 into a first chamber, a second chamber, and a third chamber from the direction close to the connecting box body 3 to the direction away from the connecting box body 3. At both the upper and lower ends on one side of the sealed box 2, air inlet pipes 53 communicating with the third chamber are provided. One end of each air inlet pipe 53 is communicated with the adjacent air storage box 5. A one-way air inlet valve 531 is installed on the air inlet pipe 53. The one-way air inlet valve 531 allows the gas in the third chamber of the sealed box 2 to enter the air storage box 5. At both the upper and lower ends of the sealed box 2, air delivery pipes 54 communicating with the first chamber are provided. A one-way air delivery valve 541 is provided on the air delivery pipe 54. The one-way air delivery valve 541 allows the gas in the air storage box 5 to enter the first chamber in the sealed box 2.

[0033] On the sides of the first piston plate 22 and the second piston plate 23 close to each other, sliding grooves are symmetrically provided. Inside each sliding groove, a slider 24 is slidably connected. On the side wall of the slider 24 on the first piston plate 22, a first rotating rod 25 is rotatably connected. On the side wall of the slider 24 on the second piston plate 23, a second rotating rod 26 is rotatably connected. The hinged part of the first rotating rod 25 and the second rotating rod 26 is rotatably connected to the inner wall of the sealed box 2. An air suction pipe 27 communicating with the third chamber is provided on the sealed box 2. A one-way air suction valve 271 is installed on the air suction pipe 27. An air discharge pipe 28 communicating with the first chamber is provided on the sealed box 2. An electromagnetic valve 281 is installed on the air discharge pipe 28. A pressure relief hole 29 communicating with the second chamber is provided on the sealed box 2.

[0034] By opening the first control valve 32, the high-temperature gas in the combustion chamber 11 enters the connecting box body 3 along the heat conduction pipe 31. Among them, the connecting box body 3 and the heat conduction pipe 31 are made of heat-insulating materials to reduce heat dissipation. The high temperature in the connecting box body 3 heats the gas in the sealed box 2. At this time, there is gas in the first chamber, and there is no gas in the spaces of the two air storage boxes 5. The temperature in the first chamber in the sealed box 2 rises, and the gas in the first chamber expands, pushing the first piston plate 22 to move towards the combustion chamber 11, so that the scraping plate 42 moves away from the sealed box 2 in the combustion chamber 11. During the process of the first piston plate 22 moving towards the combustion chamber 11, the elastic spring 21 is in a stretched state, applying a pulling force towards the installation box direction to the first piston plate 22. At the same time, the first rotating rod 25 rotates. Among them, the hinged part of the first rotating rod 25 and the second rotating rod 26 is connected by two meshing gears. During the rotation of the first rotating rod 25, the second rotating rod 26 rotates along with the first rotating rod 25, causing the second piston plate 23 to move towards the first piston plate 22. At this time, a pressure difference is formed between the third chamber and the outside, causing the external normal-temperature gas to enter the third chamber along the air suction pipe 27; When the first piston plate 22 moves to the limit towards the combustion chamber 11, the solenoid valve 281 is opened, and the first chamber is communicated with the outside through the drain pipe 28. The force generated by the pressure difference between the first chamber and the second chamber is less than the pulling force of the elastic spring 21 on the first piston plate 22, driving the first piston plate 22 to move away from the combustion chamber 11. During the process of driving the connecting rod 4 to move, the second piston plate 23 is driven to move away from the first piston plate 22 through the first rotating rod 25 and the second rotating rod 26. The pressure in the third chamber increases, causing the normal-temperature gas in the third chamber to enter the storage box 5 along the intake pipe 53, moving the sealing plate 52 and compressing the connecting spring 51. The one-way gas supply valve 541 is opened, and under the action of the connecting spring 51, the gas in the storage box 5 is sent into the first chamber through the gas supply pipe 54. Through continuous heating and expansion, the first piston plate 22 is pushed to move. While the first piston plate 22 reciprocates in the sealing box 2, the scraping plate 42 is driven to reciprocate in the combustion chamber 11 through the connecting rod 4, timely scraping off the slag blocks on the inner wall of the combustion chamber 11, facilitating the cleaning of the impurities and dust accumulated on the inner wall of the combustion chamber 11. The impurities falling in the combustion chamber 11 are discharged through the slag discharge pipe 16.

[0035] Referring to Figure 1 , a slag discharge pipe 16 communicating with the combustion chamber 11 is provided on the side wall of the housing 1, and the impurities in the combustion chamber 11 are discharged from the combustion chamber 11 through the slag discharge pipe 16.

[0036] Referring to Figure 1 , a smoke exhaust pipe 17 is connected to the top of the combustion chamber 11, and four ventilation pipes 171 facing different directions are connected to the top of the smoke exhaust pipe 17, enabling the outdoor air to smoothly enter the combustion chamber 11, providing sufficient oxygen for the combustion chamber 11, improving the flame spraying effect of the burner 15 in the combustion chamber 11, and reducing the generation of CO at the same time.

[0037] The implementation principle of a gas heater for heating an oil wellhead in an embodiment of the present application is as follows: The inner wall of the combustion chamber 11 is heated by the burner 15 spraying fire to vaporize the liquid medium and enter the heating chamber 12, increasing the temperature in the heating chamber 12, heating the crude oil in the oil pipeline 14 passing through the heating chamber 12, reducing the viscosity of the crude oil, and enhancing the fluidity of the crude oil. By opening the first control valve 32, the high-temperature gas in the combustion chamber 11 enters the connection box body 3 along the heat conduction pipe 31. The high temperature in the connection box body 3 heats the gas in the sealing box 2, driving the first piston plate 22 to move, causing the scraping plate 42 to reciprocate in the combustion chamber 11, timely scraping off the slag blocks on the inner wall of the combustion chamber 11, facilitating the cleaning of the impurities and dust accumulated on the inner wall of the combustion chamber 11. The impurities falling in the combustion chamber 11 are discharged through the slag discharge pipe 16. Embodiment 2

[0038] Reference Figure 4 and Figure 5 A purification component 6 is arranged between the connecting box body 3 and the combustion chamber 11. The purification component 6 includes a first connecting pipe 61, a purification box 62 and a second connecting pipe 63. The first connecting pipe 61 and the second connecting pipe 63 are respectively communicated with the purification box 62. The other end of the first connecting pipe 61 is communicated with the connecting box body 3, and the other end of the second connecting pipe 63 is communicated with the combustion chamber 11.

[0039] A first one-way valve 64 is arranged on the first connecting pipe 61. The first one-way valve 64 allows gas to enter the purification box 62 from the connecting box body 3. A second one-way valve 65 is installed on the second connecting pipe 63. The second one-way valve 65 allows the gas in the purification box 62 to enter the combustion chamber 11.

[0040] Two partition plates 66 are arranged in the purification box 62. A plurality of round holes 661 are opened on both of the two partition plates 66. A feeding pipe 621 located between the two partition plates 66 is communicated with the top of the purification box 62. A discharging pipe 622 located below the feeding pipe 621 is arranged at the bottom of the purification box 62. Sealing covers 6221 are arranged on both the feeding pipe 621 and the discharging pipe 622.

[0041] Open the first control valve 32. The high-temperature gas containing CO in the combustion chamber 11 enters the connecting box body 3 along the heat conduction pipe 31. Open the first one-way valve 64. The high-temperature gas containing CO in the connecting box body 3 enters the purification box 62 along the first connecting pipe 61. Put iron oxide into the purification box 62 through the feeding pipe 621. When the high-temperature gas containing CO passes through the partition plate 66 with round holes 661 in the purification box 62, the high-temperature gas is dispersed, so that CO fully contacts with the iron oxide in the purification box 62, and an oxidation reaction occurs to oxidize CO, and CO2 is generated by the reaction. Open the second one-way valve 65, so that CO2 enters the combustion chamber 11 along the second connecting pipe 63, avoiding the leakage of CO into the air. The reacted iron is discharged from the purification box 62 through the discharging pipe 622.

[0042] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape and principle of this application should be covered within the protection scope of this application.

Claims

1. A gas heater for heating an oil field wellhead, comprising a housing (1), characterized in that: A combustion chamber (11) is arranged in the shell (1), a heating chamber (12) located above the combustion chamber (11) is arranged on the shell (1), an inner wall of the shell (1) and an outer wall of the combustion chamber (11) form a heat exchange chamber (13), the heat exchange chamber (13) is communicated with the heating chamber (12), a side wall of the shell (1) is communicated with an oil delivery pipe (14), both ends of the oil delivery pipe (14) are located outside the shell (1), the oil delivery pipe (14) is arranged in a serpentine shape in the heating chamber (12), a burner (15) is arranged on the side wall of the combustion chamber (11), a slag discharge pipe (16) communicated with the combustion chamber (11) is opened on the side wall of the shell (1), a scraping assembly for cleaning the inner wall of the combustion chamber (11) is arranged on the side of the combustion chamber (11) away from the burner (15), and a purification assembly (6) is arranged on one side of the combustion chamber (11).

2. The gas heater for oilfield wellhead heating according to claim 1, characterized in that: The scraping assembly comprises a sealing box (2), the sealing box (2) being fixedly mounted on the side wall of the combustion chamber (11), a connecting box body (3) being arranged at one end of the sealing box (2) away from the combustion chamber (11), a heat conducting pipe (31) being connected between the combustion chamber (11) and the connecting box body (3), a first control valve (32) being installed on the heat conducting pipe (31), an elastic spring (21) being arranged on the inner wall of the sealing box (2) on the side close to the connecting box body (3), the end of the elastic spring (21) being connected to a first movable spring (32). The plug plate (22) is adapted to fit the inner wall of the sealing box (2) and is slidably connected to the sealing box (2). A connecting rod (4) is provided on the side wall of the first piston plate (22). An end of the connecting rod (4) away from the first piston plate (22) passes through the sealing box (2) and the combustion chamber (11) in sequence and is fixedly connected to a fixing plate (41) located in the combustion chamber (11). A scraper (42) is fixedly provided on the fixing plate (41). The outer wall of the scraper (42) is in contact with the inner wall of the combustion chamber (11).

3. A gas heater for oilfield wellhead heating according to claim 2, characterized in that: A second piston plate (23) is slidably connected inside the sealing box (2), the outer wall of the second piston plate (23) is in contact with the inner wall of the sealing box (2), the connecting rod (4) passes through the second piston plate (23) and is movably connected to the second piston plate (23), the first piston plate (22) and the second piston plate (23) divide the sealing box (2) into a first chamber, a second chamber and a third chamber from the direction close to the connecting box body (3) to the direction away from the connecting box body (3), the first piston plate (22) and the second piston plate (23) are symmetrically provided with sliding grooves on the sides close to each other, each of the sliding grooves is slidably connected with a slider (24), the side wall of the slider (24) on the first piston plate (22) is rotatably connected to a first rotating rod (25), the side wall of the slider (24) on the second piston plate (23) is rotatably connected to a second rotating rod (26), and the hinge between the first rotating rod (25) and the second rotating rod (26) is rotatably connected to the inner wall of the sealing box (2).

4. The gas heater for oil field wellhead heating according to claim 3, characterized in that: The sealed box (2) is provided with air storage boxes (5) on both upper and lower sides, the inner walls of the two air storage boxes (5) are provided with connecting springs (51), the ends of the connecting springs (51) are provided with sealing plates (52), the outer walls of the sealing plates (52) are in contact with the inner walls of the air storage boxes (5) and are slidably connected to the air storage boxes (5), and the upper and lower ends of one side of the sealed box (2) are provided with air intake pipes (53) connected to the third chamber, and one end of the air intake pipes (53) is connected to the adjacent air storage boxes (5). ) connected; a one-way air intake valve (531) is installed on the air intake pipe (53), and the one-way air intake valve (531) allows the gas in the third chamber of the sealed box (2) to enter the air storage box (5); the upper and lower ends of the sealed box (2) are provided with air supply pipes (54) connected to the first chamber, and the air supply pipe (54) is provided with a one-way air supply valve (541), and the one-way air supply valve (541) allows the gas in the air storage box (5) to enter the first chamber of the sealed box (2).

5. The gas heater for oil field wellhead heating according to claim 4, characterized in that: The sealed box (2) is provided with an air intake pipe (27) communicating with the third chamber, and a one-way air intake valve (271) is installed on the air intake pipe (27); the sealed box (2) is provided with an air discharge pipe (28) communicating with the first chamber, and a solenoid valve (281) is installed on the air discharge pipe (28); and the sealed box (2) is provided with a pressure relief hole (29) communicating with the second chamber.

6. The gas heater for oil field wellhead heating according to claim 1, characterized in that: The purification assembly (6) comprises a first connecting pipe (61), a purification box (62) and a second connecting pipe (63); the first connecting pipe (61) and the second connecting pipe (63) are respectively connected to the purification box (62); the other end of the first connecting pipe (61) is connected to the connecting box body (3); and the other end of the second connecting pipe (63) is connected to the combustion chamber (11).

7. The gas heater for oilfield wellhead heating according to claim 6, characterized in that: The first connecting pipe (61) is provided with a first one-way valve (64), the first one-way valve (64) allowing gas to enter the purification box (62) from the connecting box body (3), and the second connecting pipe (63) is provided with a second one-way valve (65), the second one-way valve (65) allowing gas in the purification box (62) to enter the combustion chamber (11).

8. The gas heater for oil field wellhead heating according to claim 6, characterized in that: Two partition plates (66) are arranged in the purification box (62), and a plurality of circular holes (661) are provided on the two partition plates (66). The top of the purification box (62) is connected to a feed pipe (621) located between the two partition plates (66). The bottom of the purification box (62) is provided with a discharge pipe (622) located below the feed pipe (621). The feed pipe (621) and the discharge pipe (622) are both provided with sealing covers (6221).

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