Raw oil reaction heating furnace

Abstract

The invention relates to the technical field of petrochemical engineering heating furnaces, in particular to a raw oil reaction heating furnace which comprises a furnace body, furnace tubes and combustors, the furnace body comprises a radiation chamber and a convection chamber, the furnace tubes penetrate into the convection chamber from the upper portion of the furnace body to be coiled and then enter the radiation chamber, and the furnace tubes are distributed in a continuous S shape close to the side wall of the radiation chamber and then penetrate out of the side wall of the radiation chamber. Combustors are arrayed at the bottom end of the radiation chamber; a plurality of air outlet holes are formed in the upper end of the radiation chamber, a plurality of inclined air inlet holes are formed in the lower end of the radiation chamber in an array mode, a plurality of circulating air pipes located on the outer side of the radiation chamber are communicated between the air outlet holes and the air inlet holes, the circulating air pipes introduce hot air at the upper end of the radiation chamber into the air inlet holes, the air inlet holes exhaust air into the radiation chamber, and flames of the burners rise spirally; heating is more stable while heat efficiency is improved, the problems of overtemperature of the lower portion and partial flame combustion are reduced, and coking of the lower portion of the furnace tube is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical heating furnaces, and in particular to a raw oil reaction heating furnace. Background Art

[0002] During the oil refining process, the crude oil is heated to a certain reaction temperature and cracked under the action of a catalyst to obtain products such as various olefins, aromatics or high-octane gasoline required for production and life; the crude oil reaction heating furnace is a commonly used heating equipment in the petrochemical field, usually including a combustion mechanism, a crude oil pipeline and a ventilation system, which transfers the energy generated by the fuel combustion to the crude oil pipeline to heat the crude oil.

[0003] At present, many experts and scholars are conducting research and improvement on reaction heating furnaces. For example, in July 2009, in Volume 31, Issue 4, Wang Yingbo and Liu Runling conducted relevant research on the problems of low efficiency and stability of the heating furnace in "Renovation Measures and Operation Suggestions for the Heating Furnace of the Reforming Unit", but did not give specific design suggestions; in Sichuan Chemical Industry, Volume 20, Issue 1, 2017, Zhang Yingzhe and Chen Hongxing conducted a transformation on the thermal efficiency and energy consumption of the reforming reaction heating furnace in "Renovation of the Continuous Catalytic Reforming Reaction Heating Furnace of Luoyang Petrochemical". The thermal efficiency of the heating furnace increased, but the energy consumption also increased, and problems such as overheating of the lower part of the furnace tube, coking of the burner and uneven flame burning occurred. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a crude oil reaction heating furnace, which can improve the thermal efficiency of the reaction heating furnace while making the heating more stable, reduce the problems of overheating and flame bias in the lower part, and avoid coking in the lower part of the furnace tube.

[0005] The technical solution adopted in this application to solve this technical problem is: A crude oil reaction heating furnace comprises a furnace body, a furnace tube and a burner. The furnace body comprises a radiation chamber and a convection chamber. The upper end of the radiation chamber is connected to the convection chamber. The furnace tube passes through the convection chamber from the upper part of the furnace body, coils inside the convection chamber and then enters the radiation chamber. The furnace tube is distributed in a continuous S shape near the side wall of the radiation chamber and then passes through the side wall of the radiation chamber. The bottom end of the radiation chamber is arrayed with burners; the upper end of the radiation chamber is provided with a plurality of air outlets located on the side of the convection chamber, and the lower end is arrayed with a plurality of inclined air inlet holes located between the burner and the furnace tube. The air outlet holes are opposite to the air inlet holes up and down, and a plurality of circulating air ducts located outside the radiation chamber are connected between the air outlet holes and the air inlet holes. The circulating air duct introduces hot air from the upper end of the radiation chamber into the air inlet holes. The air inlet holes exhaust air into the radiation chamber, so that the flames of the plurality of burners rise in a spiral shape.

[0006] The technical solution utilizes a circulating air duct to recirculate the hot air at the top of the radiation chamber to the bottom of the radiation chamber, and the air is discharged at an angle. The inclined air outlet holes of the array cause the flame of the burner to rise in a spiral shape, which can lengthen the flame length, reduce the radiation heat of the lower part of the furnace tube, and increase the radiation heating of the upper part of the furnace tube, so that the furnace tube is heated evenly and the lower part is not easy to coke. The spirally rising flame can make the heat radiation in the radiation chamber uniform. Even if the power of one or several burners fluctuates, it will not affect the radiation uniformity in the radiation chamber, thereby improving the operational stability.

[0007] Furthermore, the sum of horizontal cross-sections of the plurality of air inlet holes is S1, the sum of horizontal cross-sections of the plurality of air outlet holes is S2, and S2>S1>1 / 2S2.

[0008] The above technical solution is used to control the wind speed, which can not only increase the wind speed discharged from the air inlet hole and increase the spiral degree of the burner flame, but also avoid the impact of excessive airflow on the flame to reduce the flame combustion efficiency.

[0009] Furthermore, the angle between the center line of the air inlet and the vertical direction is θ, the height of the radiation chamber is H, the circumference of the radiation chamber is L, and H / 2L>cotθ>H / 3L.

[0010] The above technical solution ensures that the flame of the burner can rise in a spiral shape, and prevents the flame of the burner from being blown by wind with too large an angle, thereby affecting the combustion efficiency.

[0011] Furthermore, a filling column is provided in the radiation chamber, the lower part of the filling column is a cylinder, the upper end of the filling column is a cone, and the burners are arranged in a ring array around the filling column.

[0012] The function of the above-mentioned filling column is, on the one hand, to occupy the space inside the radiation chamber, to prevent the flame from gathering towards the center of the radiation chamber, but to make the flame close to the furnace tube, thereby improving thermal efficiency; on the other hand, it can also serve as the center around which the spiral rising flame surrounds, effectively promoting the annular coiling of the hot air in the air inlet and reducing turbulence.

[0013] Furthermore, a first stainless steel coating layer is provided on the surface of the filling column; the first stainless steel coating layer can reflect infrared rays, and the higher the temperature of the first stainless steel coating layer, the higher the efficiency of reflecting infrared rays, thereby effectively improving the radiation utilization rate in the radiation chamber.

[0014] Furthermore, the inner wall of the radiation chamber is arrayed with vertical grooves, and the tangent direction of the grooves is toward the furnace tube; this helps the spiral hot air to blow toward the outer wall of the furnace tube, thereby increasing the heat transfer effect.

[0015] Furthermore, the cross-section of the groove is arc-shaped, the center of the groove is located on the central axis of the furnace tube opposite to the groove, and a second stainless steel coating layer is provided on the inner wall of the groove; the second stainless steel coating layer can enhance the reflection of infrared rays, improve thermal efficiency, and ensure uniform temperature of the furnace tube wall.

[0016] Furthermore, the lower ends of the plurality of circulating air ducts are commonly connected to a fan and an air preheater, and the air outlet of the air preheater is connected to the air inlet.

[0017] The circulating air duct is not only used to circulate the hot air, but also can preheat the intake air of the burner to improve the thermal efficiency of the burner.

[0018] Furthermore, a plurality of viewing windows are provided on the side wall of the radiation chamber, and the plurality of viewing windows are arranged in a vertical direction.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention utilizes a circulating air duct to recirculate the hot air at the top of the radiation chamber to the bottom of the radiation chamber, and the air is discharged at an angle. The inclined air outlet holes of the array cause the air in the radiation chamber to rise in a spiral shape, thereby driving the flame of the burner to rise in a spiral shape. The circulating hot air increases the air intake at the lower end of the radiation chamber, and lengthens the flame length to a certain extent, reduces the temperature of the lower part of the flame, and reduces the radiation heat of the lower part of the furnace tube. The elongated flame can increase the radiation heating of the upper part of the furnace tube, and at the same time as the radiation heating, it also increases the heat transfer heating of the air, so that the furnace tube is heated evenly and the lower part is not easy to coke. The spirally rising flame can make the heat radiation in the radiation chamber uniform. Even if the power of one or several burners fluctuates, it will not affect the radiation uniformity in the radiation chamber, thereby improving the operational stability.

[0020] 2. The filling column of the present invention occupies the space inside the radiation chamber, preventing the flame from gathering at the center of the radiation chamber, but making the flame close to the furnace tube, thereby improving thermal efficiency. On the other hand, it can also serve as the center around which the spiral rising flame surrounds, effectively promoting the annular coiling of the hot air in the air inlet and reducing turbulence.

[0021] 3. The first stainless steel cladding layer and the second stainless steel cladding layer of the present invention reflect infrared rays, thereby improving the thermal efficiency of the heating furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the internal structure of the present invention (partial cross-section); Figure 3 yes Figure 2 A magnified view of part A; Figure 4 is a sectional front view of the present invention; Figure 5 yes Figure 4 BB section view.

[0023] The numbers in the attached drawings are: 1, furnace body; 2, furnace tube; 3, burner; 4, flue gas duct; 5, radiation chamber; 6, convection chamber; 7, fuel inlet pipe; 8, air inlet pipe; 9, air inlet hole; 10, circulating air duct; 11, filling column; 12, first stainless steel coating layer; 13, groove; 14, second stainless steel coating layer; 15, fan; 16, air preheater; 17, bracket; 18, maintenance platform; 19, window. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0025] like Figure 1 and Figure 2 As shown, a raw oil reaction heating furnace comprises a furnace body 1, a furnace tube 2 and a burner 3. The lower part of the furnace body 1 is a cylindrical body with a diameter of 4m and a height of 5m, and the upper part is a cylindrical body with a side length of 2m, a height of 1.5m and a square cross-section. A flue gas duct 4 is arranged at the top of the furnace body 1. A cylindrical radiation chamber 5 is arranged in the lower part of the furnace body 1. A rectangular parallelepiped convection chamber 6 is arranged in the upper part of the furnace body 1. The upper end of the radiation chamber 5 is connected to the convection chamber 6. The furnace tube 2 passes through the convection chamber 6 from the upper part of the furnace body 1, is coiled and then enters the radiation chamber 5. The furnace tube 2 is distributed in a continuous S shape along the ring near the side wall of the radiation chamber 5, and then is discharged by the radiation chamber 5. 5, a burner 3 is arrayed at the bottom end of the radiation chamber 5, and the burner 3 is connected with a fuel inlet pipe 7 and an air inlet pipe 8; the upper end of the radiation chamber 5 is provided with a plurality of air outlets located on the side of the convection chamber 6, and the lower end is arrayed with a plurality of inclined air inlet holes 9 located between the burner 3 and the furnace tube 2, the air outlet holes and the air inlet holes 9 are opposite to each other up and down, and a plurality of circulating air ducts 10 located outside the radiation chamber 5 are connected between the air outlet holes and the air inlet holes 9, and the circulating air ducts 10 introduce the hot air at the upper end of the radiation chamber 5 into the air inlet holes 9, and the air inlet holes 9 exhaust air into the radiation chamber 5, so that the flames of the plurality of burners 3 rise in a spiral shape.

[0026] The circulating air duct 10 recirculates the hot air from the top of the radiation chamber 5 to the bottom of the radiation chamber 5 and discharges air at an angle. The inclined air outlet holes of the array cause the air in the radiation chamber 5 to rise in a spiral shape, thereby driving the flame of the burner 3 to rise in a spiral shape. The circulating hot air increases the air intake at the lower end of the radiation chamber 5, lengthens the flame length to a certain extent, reduces the temperature of the lower part of the flame, and reduces the radiation heat of the lower part of the furnace tube 2. The elongated flame can increase the radiation heating of the upper part of the furnace tube 2, so that the furnace tube 2 is heated evenly and the lower part is not easy to coke. The spirally rising flame can make the heat radiation in the radiation chamber 5 uniform. Even if the power of one or several burners 3 fluctuates, it will not affect the radiation uniformity in the radiation chamber 5, thereby improving the operational stability.

[0027] The sum of the horizontal cross-sections of the plurality of air inlet holes 9 is S1, the sum of the horizontal cross-sections of the plurality of air outlet holes is S2, and S2>S1>1 / 2S2.

[0028] Compared with the air outlet, the smaller air inlet 9 can increase the wind speed, which can increase the wind speed discharged from the air inlet 9, increase the spiral degree and spiral height of the burner 3 flame, and limit the minimum value of S1 can limit the wind intensity of the air inlet 9, avoiding the impact of excessive airflow on the flame and causing a decrease in the flame combustion efficiency.

[0029] The angle between the center line of the air inlet hole 9 and the vertical direction is θ, the height of the radiation chamber 5 is H, the circumference of the radiation chamber 5 is L, and H / 2L>cotθ>H / 3L.

[0030] The above restriction can limit the number of spiral rising circles of the flame to 2-3 circles, which can not only ensure that the flame of the burner 3 can rise in a spiral shape, but also prevent the flame of the burner 3 from being blown by wind with too large an angle, thereby affecting the combustion efficiency.

[0031] like Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, a filling column 11 is provided in the radiation chamber 5 , the lower part of the filling column 11 is a cylinder, the upper end of the filling column 11 is a cone, and the burners 3 are distributed in a ring array around the filling column 11 .

[0032] The function of the filling column 11 is to occupy the space inside the radiation chamber 5, prevent the flame from gathering towards the center of the radiation chamber 5, and instead make the flame approach the furnace tube 2 to improve thermal efficiency. On the other hand, it can also serve as the center around which the spiral rising flame surrounds, effectively promoting the annular coiling of the hot air in the air inlet 9 and reducing turbulence.

[0033] like Figure 5As shown, a first stainless steel coating layer 12 is provided on the surface of the filling column 11; the first stainless steel coating layer 12 is a layered structure formed by coating the outside of the filling column with stainless steel material, and the outer surface of the first stainless steel coating layer 12 is smooth. The first stainless steel coating layer 12 can reflect infrared rays when heated by flames, and the higher the temperature of the first stainless steel coating layer 12, the higher the efficiency of reflecting infrared rays, thereby effectively improving the radiation utilization rate in the radiation chamber 5.

[0034] like Figure 5 As shown, vertical grooves 13 are arranged on the inner wall of the radiation chamber 5, and the tangent direction of the grooves 13 faces the furnace tube 2, which helps the spiral hot air to blow toward the wall of the furnace tube 2, thereby increasing the heat transfer effect.

[0035] The cross section of the groove 13 is arc-shaped, and the center of the groove 13 is located on the central axis of the furnace tube 2 opposite to the groove 13. A second stainless steel coating layer 14 is provided on the inner wall of the groove 13; the second stainless steel coating layer 14 has the same function as the first stainless steel coating layer, so that the infrared rays radiated to the second stainless steel coating layer 14 are reflected to the outer wall of the furnace tube 2 facing away from the flame, thereby improving the thermal efficiency and ensuring the uniform temperature of the outer wall of the furnace tube 2.

[0036] The lower ends of the plurality of circulating air ducts 10 are commonly connected to a fan 15 and an air preheater 16. The air preheater 16 includes but is not limited to conventional tubular and plate-type air heat exchangers, and may also be other mechanisms capable of exchanging heat between hot air and the air inlet pipe 8. The air outlet of the air preheater 16 is connected to the air inlet hole 9. The circulating air duct 10 is not only used to circulate the hot air, but also can preheat the intake air of the burner 3 to improve the thermal efficiency of the burner 3.

[0037] like Figure 1 As shown, the furnace body 1 of the present invention is supported by a bracket 17, a maintenance platform 18 is provided at the lower end of the outer wall of the furnace body 1, and a plurality of viewing windows 19 are provided on the side wall of the radiation chamber 5. The plurality of viewing windows 19 are arranged in a vertical direction for observing the flame combustion state in the radiation chamber 5.

[0038] The use principle of the present invention is as follows: When the burner 3 is burning, the fan 15 is started to introduce the hot air from the upper end of the radiation chamber 5 into the lower end of the radiation chamber 5 and discharge it from the air inlet 9. The wind discharged from the air inlet 9 stretches and raises the flame, reduces the temperature of the lower part of the flame, and the flame rises in a spiral around the filling column 11, which can produce more comprehensive infrared radiation. At the same time, the radiation is more concentrated on the furnace tube through the reflection effect of the first stainless steel coating layer 12 on the filling column 11 and the second stainless steel coating layer 14 on the groove 13, and the furnace tube is heated to make the furnace tube in the radiation chamber 5 evenly heated. A part of the flue gas rising to the top of the radiation chamber 5 is transferred to the lower end of the radiation chamber 5 by the circulating air duct 10, and the other part of the flue gas enters the convection chamber 6, exchanges heat with the furnace tube in the convection chamber 6, and preheats the raw oil in the furnace tube. When the raw oil enters the radiation chamber 5, it can be quickly heated to the specified temperature and contact with the catalyst to produce a cracking reaction.

[0039] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

Claims

1. A crude oil reaction heating furnace, comprising a furnace body (1), a furnace tube (2) and a burner (3), wherein the furnace body (1) comprises a radiation chamber (5) and a convection chamber (6), wherein the upper end of the radiation chamber (5) is connected to the convection chamber (6), wherein the furnace tube (2) passes through the convection chamber (6) from the upper part of the furnace body (1), is coiled and then enters the radiation chamber (5), wherein the furnace tube (2) is distributed in a continuous S shape near the side wall of the radiation chamber (5), and then passes through the side wall of the radiation chamber (5), wherein the bottom end of the radiation chamber (5) is provided with a burner (3), wherein the furnace tube (2) is arranged in an array, wherein the heat treatment unit (1) is provided with a plurality of heat treatment units (2) and a plurality of heat treatment units (3) are provided, wherein the heat treatment unit (1) is provided with a plurality of heat treatment units (3 ... The upper end of the radiation chamber (5) is provided with a plurality of air outlets located on the side of the convection chamber (6), and the lower end is provided with a plurality of inclined air inlet holes (9) located between the burner (3) and the furnace tube (2). The air outlet holes and the air inlet holes (9) are opposite to each other in vertical direction, and a plurality of circulating air ducts (10) located outside the radiation chamber (5) are connected between the air outlet holes and the air inlet holes (9). The circulating air ducts (10) introduce hot air from the upper end of the radiation chamber (5) into the air inlet holes (9), and the air inlet holes (9) exhaust air into the radiation chamber (5), so that the flames of the plurality of burners (3) rise in a spiral shape.

2. The feedstock oil reaction heating furnace according to claim 1, characterized in that: The sum of the horizontal cross-sections of the plurality of air inlet holes (9) is S1, the sum of the horizontal cross-sections of the plurality of air outlet holes is S2, and S2>S1>1 / 2S2.

3. The feedstock oil reaction heating furnace according to claim 1, characterized in that: The angle between the center line of the air inlet hole (9) and the vertical direction is θ, the height of the radiation chamber (5) is H, the circumference of the radiation chamber (5) is L, and H / 2L>cotθ>H / 3L.

4. The feedstock oil reaction heating furnace according to claim 1, characterized in that: A filling column (11) is provided in the radiation chamber (5); the lower portion of the filling column (11) is a cylinder, the upper end of the filling column (11) is a cone, and the burners (3) are arranged in a ring array around the filling column (11).

5. The feedstock oil reaction heating furnace according to claim 4, characterized in that: A first stainless steel coating layer (12) is provided on the surface of the filling column (11); the first stainless steel coating layer (12) is capable of reflecting infrared rays, and the higher the temperature of the first stainless steel coating layer (12), the higher the efficiency of reflecting infrared rays, thereby effectively improving the radiation utilization rate in the radiation chamber (5).

6. The feedstock oil reaction heating furnace according to claim 1, characterized in that: The inner wall of the radiation chamber (5) is provided with an array of vertical grooves (13), wherein the tangent direction of the grooves (13) faces the furnace tube (2); this helps the spiral hot air to blow toward the wall of the furnace tube (2), thereby increasing the heat transfer effect.

7. The feedstock oil reaction heating furnace according to claim 6, characterized in that: The cross section of the groove (13) is arc-shaped, the center of the groove (13) is located on the central axis of the furnace tube (2) directly facing the groove (13), and a second stainless steel coating layer (14) is provided on the inner wall of the groove (13); the second stainless steel coating layer (14) can enhance the reflection of infrared rays, improve thermal efficiency, and ensure uniform temperature of the furnace tube (2) wall.

8. The feedstock oil reaction heating furnace according to claim 1, characterized in that: The lower ends of the plurality of circulating air ducts (10) are commonly connected to a fan (15) and an air preheater (16), and the air outlet of the air preheater (16) is connected to the air inlet (9).

9. The feedstock oil reaction heating furnace according to claim 1, characterized in that: A plurality of viewing windows (19) are provided on the side wall of the radiation chamber (5), and the plurality of viewing windows (19) are arranged in a vertical direction.

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