A compact and low-energy consumption open-type ground flare system

Abstract

A compact low-energy consumption open ground flare system, characterized in that: it includes a flare gas main pipe, a radiation protection screen, a grading pipe, a grading valve, a self-variable diameter flare burner, a micro-vortex burner, a pilot burner and a grading control system. By setting a self-variable diameter flare burner at the first stage, this open ground flare system can effectively solve the problem of incomplete combustion of conventional flare burners under small flow rate discharge conditions, save steam and nitrogen consumption, and reduce operating costs. By setting micro-vortex burners at each stage, the layout spacing between adjacent burners can be reduced, making the combustion area more compact, thus saving floor space.

Description

Technical Field

[0001] The present invention relates to a flammable gas emission technology in the petrochemical industry, especially a flare burner technology, specifically a compact low-energy open ground flare system. Background Art

[0002] The first stage of a conventional open ground flare system is a normally open stage, which is used to handle the flare gas in normal small-flow discharge conditions. When the flare gas pressure is lower than the smokeless combustion pressure in small-flow conditions, it will cause problems such as incomplete combustion, black smoke, excessive pollutants, excessive radiation, and carbon deposition. In addition to the first stage, the second and third stages of a conventional open ground flare system are limited by the boundary pressure, and the designed lifting pressure of the grading valve often is also lower than the smokeless combustion pressure, resulting in the same problems. In practical engineering applications, in order to solve the above problems, steam soot suppression is often required. In addition, in order to prevent flashback, a conventional open ground flare system needs to continuously purge the first-stage grading pipe and the burner with nitrogen. These soot-suppressing steam and purging nitrogen undoubtedly increase the daily operating cost of the system.

[0003] In addition, in recent years, with the increasing application of open ground flares, their design scale has also become larger and larger. The processing capacity of thousands of tons or the number of burners of thousands of sets restricts their use in some places with limited land. In order to reduce the system footprint and expand the application scenarios of open ground flares, it can be achieved by increasing the processing capacity of a single burner and reducing the layout spacing between adjacent burners. However, increasing the processing capacity of a single burner will cause the flame to become longer and result in flame-out phenomenon. Narrowing the layout spacing between adjacent burners may cause the flames of adjacent burners to adhere, resulting in incomplete combustion, flame-out, and black smoke. Summary of the Invention

[0004] The purpose of the present invention is to invent a compact low-energy open ground flare system in view of the disadvantages of the existing conventional open ground flare system, such as high operating cost and large floor area, which can effectively reduce the consumption of soot-suppressing steam and purging nitrogen, save operating costs, and at the same time can narrow the layout spacing between adjacent burners, making the combustion area more compact, thereby saving floor area.

[0005] The technical solution of the present invention is as follows:

[0006] A compact low-energy open ground flare system, characterized in that it includes a flare gas main pipe, a radiation shield, a grading pipe, a grading valve, a self-variable diameter flare burner, a micro-vortex burner, a pilot burner, and a grading control system. The grading pipe extends from the flare main pipe and passes through the radiation shield into the combustion zone. Each grading pipe in the combustion zone is connected to several stages of flare burners. The first-stage flare burner is provided with a self-variable diameter flare burner and a micro-vortex burner in proportion at the same time, and the remaining stages of flare burners are all provided with micro-vortex burners. The first-stage flare burner is a normally open stage, and no grading valve is provided on the grading pipe of this stage of flare burner. Grading valves are provided on the grading pipes of the remaining stages of flare burners, and the grading control system controls the opening or closing of the grading valves according to the flow rate or pressure of the flare gas main pipe. The first-stage flare burner uses a self-variable diameter flare burner, and its pressure-holding effect can consume less nitrogen under the same nitrogen purging speed, reducing the operating cost. The spacing of the micro-vortex burners is small, which can save the floor area and reduce the construction cost while realizing the flame transfer between the burners.

[0007] The top of the gas pipe of the micro-vortex burner is provided with 4 to 8 branches, and 1 to 3 rows of gas spray holes are opened on each branch. The number of spray holes near the center of the burner is small, and the number of spray holes far from the center is large. The branches are streamlined, that is, the cross-sectional area of each branch continuously decreases from the center to the end. The top surface of the branch has an angle of 10° to 20° with the horizontal plane, and the end of the branch is upturned, forming an angle of 5° to 10° with the horizontal plane.

[0008] The branches of the micro-vortex burner are divided into two types, type A and type B. The difference is that a pilot hole is provided at the end of the type B branch for flame transfer between adjacent burners.

[0009] The micro-vortex burner is provided with a steam soot suppression structure, which includes a steam pipe, a support frame, a steam ring pipe, a steam riser pipe, a steam spray head, and a steam spray hole. The steam pipe is connected to the steam ring pipe installed on the support frame. The steam riser pipe is connected to the steam ring pipe. The steam spray head is connected to the steam riser pipe. The branches and the steam spray heads are arranged in pairs, and the steam spray heads are arranged as close as possible to the branches.

[0010] The specific structure of the self-variable diameter flare burner is as described in the invention patent "Sonic Automatic Adjustable Flare Combustion System" (ZL201310479810.5). It presses the flare gas in the pipeline by the gravity of its head, so that the small-flow flare gas can only be discharged from the spray holes of other non-self-variable diameter burners for combustion, which can increase the pressure in the pipeline to the smokeless pressure, thereby reducing or even completely eliminating the need to consume steam and reducing the system operating cost.

[0011] The branches of the micro-vortex burner are streamlined, and the cross-sectional area of each branch gradually decreases from the center of the burner to the end, so as to ensure that the gas spray holes far from the center can still obtain the same outlet flow rate as the gas spray holes close to the center.

[0012] For the micro-whirl combustor, the number of gas injection holes on its branches is smaller near the center of the combustor and larger away from the center. When ensuring the same outlet flow velocity of the gas injection holes, the gas volume is smaller near the center and larger away from the center, which can avoid incomplete combustion caused by insufficient oxygen supply at the flame center, avoid problems such as smoke emission, carbon deposition, and elongated flame, and enable the micro-whirl combustor to form a short and squat flame.

[0013] For the micro-whirl combustor, its head branches are divided into Type A and Type B. Each set of combustors has 2 - 6 Type A branches and 2 Type B branches. In addition to realizing the combustion of flare gas, the Type B branches can also realize the transfer of flame between combustors.

[0014] In the steam soot elimination structure of the micro-whirl combustor, the steam nozzles and branches are arranged in pairs, and the steam nozzles are arranged close to the branches. When the combustor is working, it can quickly mix the soot elimination steam and the flare gas, enabling the flare gas to complete combustion in the shortest possible time and further shortening the flame length.

[0015] For the compact low-energy consumption open-type ground flare system, in the first stage, pilot lights are arranged beside the variable-diameter flare burner and the first micro-whirl combustor, and the remaining micro-whirl combustors realize flame transfer through Type B branches; in the other stages of the flare system, a pilot light is arranged beside the first micro-whirl combustor, and the remaining micro-whirl combustors realize flame transfer through Type B branches; in this way, the floor area can be reduced and the construction cost can be lowered.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. It solves the shortcoming of incomplete combustion in the small-flow discharge condition of the conventional open-type ground flare system, ensures a stable short and squat flame, thereby reducing the amount of soot elimination steam and lowering the operation cost;

[0018] 2. When using the conventional open-type ground flare system, in order to prevent backfire in the small-flow condition, nitrogen needs to be continuously purged in the first stage. In the present invention, part of the variable-diameter flare burner is used in the first stage, and its pressure-holding effect can consume less nitrogen under the same nitrogen purging speed, thereby reducing the operation cost.

[0019] 3. The system of the present invention uses micro-whirl combustors, reduces the layout spacing of the combustors, can realize the transfer of flame between the combustors, saves the floor area, and reduces the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the compact low-energy consumption open-type ground flare system of the present invention.

[0021] Figure 2 It is a schematic structural diagram of the variable-diameter burner.

[0022] Figure 3 It is a schematic structural diagram of an optional embodiment of a micro-swirl burner.

[0023] Figure 4 It is a top view of the structure of an optional embodiment of a micro-swirl burner.

[0024] Figure 5 They are schematic structural diagrams of two different structures of the branches of the micro-swirl burner. In the figure, area C represents a small number of holes near the central nozzle, and area D represents a large number of holes at the outer ends of the branches.

[0025] Figure 6 It is a layout diagram between adjacent micro-swirl burners.

[0026] Among them, 1 - variable-diameter torch burner, 2 - micro-swirl burner, 3 - gas pipe, 4 - branch, 5 - steam pipe, 6 - support frame, 7 - steam manifold, 8 - steam riser, 9 - steam nozzle, 10 - steam hole, 11 - gas hole, 12 - ignition hole, 13 - torch main pipe, 14 - radiation shield, 15 - staging pipe, 16 - staging valve, 17 - pilot light, 18 is type A branch (without ignition hole), 19 is type B branch (with ignition hole). Specific embodiments

[0027] The present invention will be further described below in conjunction with the drawings and embodiments.

[0028] Figure 2 For the specific working principle and structure of the shown variable-diameter torch burner 1, reference can be made to the patent "Sonic Automatic Adjustable Torch Combustion System" (Patent No.: ZL 2013 1 0479810.5).

[0029] As Figure 1 shown.

[0030] A compact low-energy open ground torch system includes a torch gas main pipe 13, a radiation shield 14, a staging pipe 15, a staging valve 16, a variable-diameter torch burner 1, a micro-swirl burner 2, a pilot light 17, and a staging control system (existing conventional technology). The staging pipe 15 extends from the torch gas main pipe 13, passes through the radiation shield 14 and enters the combustion zone. Each staging pipe in the combustion zone is connected to a number of stages of torch burners. The first-stage torch burner is in proportion ( Figure 1The ratio in the middle is 1:1, which can be calculated and set according to needs during specific implementation). At the same time, a variable-diameter torch burner 1 and a micro-vortex burner 2 are set, and the remaining levels of torch burners are all set with micro-vortex burners 2; the first-level torch burner is the normally open level, and a grading valve 16 is not set on the grading pipe 15 of this level of torch burner, while grading valves 16 are set on the grading pipes 15 of the remaining levels of torch burners, and the grading control system controls the opening or closing of the grading valve 16 according to the flow rate or pressure of the torch gas main pipe; the variable-diameter torch burner 1 adopted on the first-level torch burner can consume less nitrogen under the same nitrogen purging speed, reducing the operating cost; the micro-vortex burners 2 have a small spacing, which can save floor space and reduce construction costs while enabling flame transfer between burners.

[0031] As Figures 3 to 5 shown, Figures 3 - 5 Figure 7 is a schematic structural diagram of the micro-vortex burner. Its working principle is: the torch gas enters the burner head branches 4 from the gas pipe 3. The branches 4 are divided into type A and type B. The difference between the two is that a pilot hole 12 is provided at the end of the type B branch 19 for flame transfer between adjacent burners, as Figure 5 shown. Each set of burners has 2 to 6 type A branches and 2 type B branches, and 1 to 3 rows of gas spray holes 11 are opened on each branch 4, as shown in Figure 5 . The torch gas burns after spraying out from the gas spray holes 11. The following designs can make the micro-vortex burner 2 form a short and thick flame:

[0032] (1) The gas spray holes 11 are arranged differently. As Figures 4 to 5 shown, the number of gas spray holes 11 near the center of the burner is small, and the number of gas spray holes far from the center is large, that is, the torch gas flow is less inside and more outside. Such a design can avoid problems such as incomplete combustion caused by insufficient oxygen supply at the flame center, resulting in smoke and carbon deposition and long flames.

[0033] (2) As Figure 5 shown, the branches 4 are streamlined, that is, the cross-sectional area of each branch 4 continuously decreases from the center to the end, so as to ensure that the gas spray holes 11 far from the center can still obtain the same outlet flow velocity as the gas spray holes near the center, and avoid the flame from becoming too long due to too high local torch gas flow.

[0034] (3) The top surface of the branch 4 has an angle θ with the horizontal plane. As Figure 5 shown, the size of θ is 10° to 20°. This design can convert part of the vertical kinetic energy of the gas into horizontal kinetic energy. The decrease in vertical kinetic energy can reduce the flame height, and the increase in horizontal kinetic energy can enable the gas to obtain a tangential velocity when spraying out, forming a weak swirl, which can strengthen the mixing of the torch gas and air and make the combustion more complete, further ensuring that the flame will not be too long.

[0035] (4) The end of branch 4 is tilted upward, forming an angle ψ with the horizontal plane, as shown in Figure 3 As shown, the value of ψ is 5° to 10°. This design can gather the fire and make the flame thinner.

[0036] (5) The thin flame of the micro-rotation burner 2 may cause unstable flame transmission between adjacent burners when the ambient wind speed is high. However, if a long-burning lamp 17 is provided for each micro-rotation burner 2, the investment cost will be greatly increased. In order to solve this problem, two types of branches, type A and type B, are provided on the micro-rotation burner 2. Type B branches are generally provided with two, such as Figure 4 The difference between type A and type B is that the end of the type B branch 4 is provided with an ignition hole 12 for ensuring the flame transmission effect between adjacent burners. In practical applications, the arrangement of the micro-rotation burner 2 is as follows Figure 6 As shown, the B-type branches of adjacent micro-rotation burners cooperate with each other to complete the flame transmission.

[0037] (6) The micro-rotation burner 2 is also provided with a steam smoke elimination structure, such as Figure 3 As shown, it includes a steam pipe 5, a support frame 6, a steam ring pipe 7, a steam riser 8, a steam nozzle 9, and a steam nozzle hole 10. The steam nozzle 9 and the branch 4 are arranged in pairs, and the steam nozzle 9 is as close to the branch 4 as possible. This design can make the smoke elimination steam and the flare gas mix quickly, so that the flare gas can be burned in the shortest possible time, shortening the flame length.

[0038] Figure 1 The figure shows an embodiment of a compact low-energy consumption open ground flare system, which includes a flare main pipe 13, a radiation shield 14, a stepping pipe 15, a stepping valve 16, a self-variable burner 1, a micro-rotation burner 2, and a long-burning lamp 17. In this embodiment, the flare system is divided into five levels, wherein the first level is a normally open level, and no stepping valve 16 is provided on the stepping pipe 15 of this level, and 4 sets of self-variable burners 1 and 4 sets of micro-rotation burners 2 are arranged at this level. Stepping valves 16 are provided on the stepping pipes 15 of the remaining levels, and the stepping valves 16 are controlled to be opened or closed by the stepping control system according to the flow rate or pressure of the flare gas main pipe 13, and micro-rotation burners 2 are all provided on the second to fifth levels.

[0039] This configuration has the following advantages:

[0040] 1) If all the burners in the first stage adopt conventional burners, when the incoming flow from the flare header 13 is in a small discharge condition, the pressure is relatively low and cannot reach the smokeless combustion pressure. At this time, black smoke will be generated during combustion. To prevent the generation of black smoke, steam needs to be set for smoke elimination. Here, some of the burners in the first stage are replaced with variable-diameter flare burners 1. It can press the flare gas in the pipeline by the gravity of the head, so that the small-flow flare gas can only be discharged from the nozzles of other non-variable-diameter burners for combustion. In this way, the pressure in the pipeline can be increased to the smokeless pressure, thereby reducing or even completely eliminating the need to consume steam and reducing the operating cost.

[0041] 2) When using conventional burners, in order to prevent flashback during small-flow conditions, nitrogen needs to be continuously purged through the first stage. After using the variable-diameter flare burner 1, its pressure-holding effect can consume less nitrogen under the condition of achieving the same nitrogen purging speed, and the operating cost can also be reduced.

[0042] 3) Since the flare is in a small-flow discharge condition in the vast majority of cases during operation, although only variable-diameter burners 1 are set in the first stage, the operating cost can still be significantly reduced. It should be noted that if all the first stage is set as variable-diameter burners 1, it may cause the pressure of the entire flare system to be too high, and there may be safety risks. Therefore, in this embodiment, only some variable-diameter burners 1 are adopted in the first stage. In actual applications, the number of variable-diameter burners can be adjusted according to actual needs to achieve the optimal effect.

[0043] 4) Some micro-vortex burners 2 are adopted in the first stage, and all the other stages except the first stage adopt micro-vortex burners 2. Then, the characteristics of the micro-vortex burners to form thin and short flames during combustion can be utilized to reduce the layout spacing between adjacent burners without flame adhesion, thereby saving land. It should be pointed out that the land occupation of the entire open ground flare system can be divided into the land occupation of the combustion area (i.e., the land occupation of the burner part) and the land occupation of the non-combustion area. The present invention belongs to reducing the land occupation of the combustion area. Therefore, the larger the system throughput, the more obvious the advantage of saving land.

[0044] The above is only one embodiment of the present invention, and it does not impose any form of limitation on the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

[0045] The parts not involved in the present invention are the same as the prior art or can be implemented by the prior art.

Claims

1. A compact and low - energy - consuming open - type ground flare system, characterized in that, It includes a flare gas main pipe, a radiation shield, a grading pipe, a grading valve, a self-variable diameter flare burner, a micro-vortex burner, a pilot burner, and a grading control system. The grading pipe extends from the flare gas main pipe, passes through the radiation shield, and enters the combustion zone. Each grading pipe in the combustion zone is connected to several stages of flare burners. The first-stage flare burner is provided with a self-variable diameter flare burner and a micro-vortex burner in proportion at the same time, and the remaining stages of flare burners are all provided with micro-vortex burners; the first-stage flare burner is the normally open stage, and no grading valve is provided on the grading pipe of this stage of flare burner, while grading valves are provided on the grading pipes of the remaining stages of flare burners. The grading control system controls the opening or closing of the grading valve according to the flow rate or pressure of the flare gas main pipe; the first-stage flare burner uses a self-variable diameter flare burner, and its pressure-holding effect can consume less nitrogen under the same nitrogen purging speed, reducing the operating cost; the spacing of the micro-vortex burners is small, which can save the floor area and reduce the construction cost while realizing the flame transfer between the burners.

2. The compact low-energy consumption open-type ground flare system according to claim 1, wherein At the top of the gas pipe of the micro-vortex burner, 4 to 8 branches are provided, and 1 to 3 rows of gas spray holes are opened on each branch. The number of spray holes near the center of the burner is small, and the number of spray holes far from the center is large. The branches are streamlined, that is, the cross-sectional area of each branch continuously decreases from the center to the end. The top surface of the branch has an angle of 10° to 20° with the horizontal plane, and the end of the branch is upturned, forming an angle of 5° to 10° with the horizontal plane.

3. The compact low-energy consumption open-type ground flare system according to claim 2, characterized in that, The branches of the micro-vortex burner are divided into two types, type A and type B. The difference is that a pilot hole is provided at the end of the type B branch for flame transfer between adjacent burners; each set of micro-vortex burners has 2 to 6 type A branches and 2 type B branches. The type B branch can not only realize the combustion of the flare gas but also realize the transfer of the flame between the burners.

4. The compact low-energy consumption open-type ground flare system according to claim 2, wherein, The micro-vortex burner is provided with a steam soot suppression structure, which includes a steam pipe, a support frame, a steam ring pipe, a steam riser pipe, a steam spray head, and a steam spray hole. The steam pipe is connected to the steam ring pipe installed on the support frame, the steam riser pipe is connected to the steam ring pipe, the steam spray head is connected to the steam riser pipe, and the branches and the steam spray heads are arranged in pairs, and the steam spray heads are arranged as close as possible to the branches.

5. The compact low-energy consumption open-type ground flare system according to claim 3, characterized in that, Pilot burners are provided beside the self-variable diameter flare burner and the first micro-vortex burner in the first-stage flare burner, and the remaining micro-vortex burners realize flame transfer by relying on the type B branches; in the remaining stages of flare burners of the flare system, a pilot burner is provided beside the first micro-vortex burner, and the remaining micro-vortex burners realize flame transfer by relying on the type B branches.

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