A backfire prevention device for a refining furnace charging system

Abstract

This utility model relates to the field of refining furnace technology, specifically to a backfire prevention device for a refining furnace charging system. It includes a feeding pipe, a receiving hopper, and a connecting pipe. The feeding pipe is located above the receiving hopper, and the connecting pipe is connected to the bottom of the receiving hopper. The connecting pipe includes a baffle, a support plate, a connecting plate, and a pin. The feeding pipe is inclined, and the baffle blocks the outlet of the feeding pipe and is perpendicular to the inlet of the receiving hopper. The bottom of the baffle is 1.95-2.65m from the bottom of the connecting pipe. The upper end of the baffle is fixedly connected to the lower end of the connecting plate. The other end of the connecting plate is hinged to the support plate via a pin. The other end of the support plate is fixed to the feeding pipe and is parallel to the inlet of the receiving hopper. Multiple guide holes are provided on the feeding pipe. This achieves the effect of sealing off fire and smoke; furthermore, it replaces nitrogen sealing devices, greatly reducing energy consumption and production costs.

Description

Technical Field

[0001] This utility model relates to the technical field of anti-backfire devices for refining furnaces, specifically an anti-backfire device for a refining furnace charging system. Background Technology

[0002] The refining furnace charging system is one of the key pieces of equipment in the refining furnace system, and the flashback prevention device is a nitrogen sealing device. The nitrogen sealing device continuously introduces nitrogen gas into the charging pipeline, keeping the pipeline constantly filled with gas to prevent high-temperature flames from entering the conveyor belt system through the charging pipe and burning out the belt. During production, the refining furnace requires a continuous supply of nitrogen gas, resulting in huge energy consumption and potential hazards such as pipeline leaks and pressure fluctuations. Therefore, a technical upgrade to the flashback prevention device is urgently needed. Utility Model Content

[0003] The purpose of this invention is to provide a backfire prevention device for a refining furnace feeding system to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a backfire prevention device for a refining furnace charging system, comprising a feeding pipe, a receiving hopper, and a short-connecting pipe. The feeding pipe is located above the receiving hopper, and the short-connecting pipe is connected to the bottom of the receiving hopper. Based on the prior art, the backfire prevention device of this utility model further includes a baffle, a support plate, a connecting plate, and a pin. The feeding pipe is inclined, the baffle blocks the outlet of the feeding pipe and is perpendicular to the inlet of the receiving hopper. The bottom of the baffle is 1.95-2.65m away from the bottom of the short-connecting pipe. The upper end of the baffle is fixedly connected to the lower end of the connecting plate. The other end of the connecting plate is hinged to the support plate by a pin. The other end of the support plate is fixed to the feeding pipe and is parallel to the inlet of the receiving hopper. The feeding pipe has multiple guide holes.

[0005] Preferably, the number of the guide holes is 2-4.

[0006] Preferably, the diameter of the guide hole is 80-180mm.

[0007] Preferably, the distance between the guide hole and the discharge port along the axial direction of the feed pipe is 3.5-5m.

[0008] Preferably, the inclination angle of the feed tube is 30-70°.

[0009] Preferably, it also includes a support rod and a chain buckle. The support rod is located above the support plate and is fixed to the feed tube parallel to the support plate. One end of the chain buckle is connected to the support rod, and the other end is connected to the baffle plate.

[0010] Preferably, the connecting plate is L-shaped.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0012] The backfire prevention device of this patent achieves the purpose of feeding material and the effect of sealing off fire and smoke. On the other hand, it replaces the nitrogen sealing device, which greatly reduces energy consumption, reduces production costs, and eliminates the hidden dangers of backfire, smoke, and belt burn caused by leakage and pressure fluctuations in the nitrogen sealing device. At the same time, the device has a simple structure, low failure rate, reduces the labor intensity of inspection and maintenance, reduces maintenance costs, and can ensure the smooth operation of production.

[0013] The annual cost savings are as follows, based on statistics:

[0014] Each refining furnace nitrogen sealing device consumes approximately 980 m³ of nitrogen per day. The annual direct economic benefit X = daily nitrogen consumption × unit price of nitrogen per cubic meter × number of operating days, X = 980 × 0.2 yuan × 350. After the upgrade, each refining furnace saves approximately 69,000 yuan in nitrogen costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the anti-backfire device in the refining furnace feeding system of this utility model.

[0016] In the diagram: 1. Feeding pipe; 2. Receiving hopper; 3. Short-connecting pipe; 4. Baffle; 5. Support plate; 6. Connecting plate; 7. Pin shaft; 8. Guide hole; 9. Support rod; 10. Chain buckle. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0018] Please see Figure 1This utility model provides a technical solution: a backfire prevention device for a refining furnace charging system, comprising a feeding pipe 1, a receiving hopper 2, a short-connecting pipe 3, a baffle 4, a support plate 5, a connecting plate 6, and a pin 7. The feeding pipe 1 is located above the receiving hopper 2 and is inclined at an angle of 30-70°. In this embodiment, the inclination angle θ of the feeding pipe 1 is 50°. The baffle 4 blocks the outlet of the feeding pipe 1 and is perpendicular to the inlet of the receiving hopper 2. The bottom of the baffle 4 is 1.95 meters away from the bottom of the short-connecting pipe 3. -2.65m. In this embodiment, the height H of the bottom of the baffle 4 from the bottom of the short-connecting pipe 3 is 2.1m. The upper end of the baffle 4 is fixedly connected to the lower end of the connecting plate 6. The other end of the connecting plate 6 is hinged to the support plate 5 through a pin 7. The connecting plate 6 can rotate around the pin 7. The other end of the support plate 5 is fixed on the feeding pipe 1 and is set parallel to the inlet of the receiving hopper 2. A guide hole 8 is opened along the axial direction of the feeding pipe 1 at a position 3.5-5m (4.6m in this embodiment) away from the outlet of the feeding pipe 1. In this embodiment, the baffle 4 is a self-closing mechanical baffle to achieve the effect of receiving material and sealing the fire. In this embodiment, the guide hole 8 is designed to achieve the purpose of smoke exhaust. The baffle 4 and the guide hole 8 work together to achieve the purpose of feeding material without accumulating material, and the material can also break through the baffle 4 and fall into the receiving hopper 2. After feeding, the baffle 4 can automatically close to achieve the effect of sealing the fire and smoke.

[0019] In this embodiment, the bottom of the baffle 4 is 2.1m above the bottom of the short-connecting pipe 3. The rationality of this height is verified by the following steps.

[0020] The installation position (height H) of the baffle 4 in the feed pipe 1 must meet the following requirements:

[0021] During feeding: the material relies on kinetic energy to break through baffle 4, and there is no accumulation of material.

[0022] When material is stopped: Baffle 4 closes automatically by gravity, sealing the flame and flue gas inside the furnace.

[0023] In this embodiment, the total length of the feed tube 1 is L=6 m. The material characteristics of this embodiment are: alloy particles (density ρ≈2500 kg / m³, angle of repose θ≈35°).

[0024] The calculation logic for the position of baffle 4 is as follows:

[0025] 1. Energy conversion analysis: The falling material process satisfies the law of conservation of mechanical energy: potential energy (Ep) → kinetic energy.

[0026] Material from the pipe opening ( = 6 m) fell to position 4 of the baffle (H=2.1 m), height difference:

[0027] Δh = 6 − 2.1 = 3.9 m,

[0028] The theoretical speed v when reaching baffle 4:

[0029] ,

[0030] Note: This speed provides the kinetic energy to break through baffle 4.

[0031] 2. Baffle mechanical design

[0032] Baffle 4 must satisfy the torque balance equation:

[0033] Breaking torque ( >Closing torque ( ),

[0034] Closing torque (generated by the weight of baffle 4):

[0035] = G× × cosα,

[0036] Where: G: weight of the baffle (baffle mass m = 15 kg, then G = 147 N), : Distance from the center of gravity of baffle 4 to pin 7 (taken as 0.3 m), α: Inclination angle of baffle 4 (α=0° when closed, cos0°=1), Breaking torque (generated by the impact force of the material):

[0037] = × ,

[0038] Impact With material flow Related to velocity v:

[0039] = ×v (Typical flow rate) =30 kg / s),

[0040] = 30×8.74≈262.2 N.

[0041] 3. Anti-material accumulation verification

[0042] The receiving hopper has two openings: the opening diameter is ϕ730 mm (diameter > 10 times the maximum size of the material).

[0043] Baffle 4 tilt angle: tilt angle when closed > (Take 45° > 35° to avoid material accumulation).

[0044] 4. Sealing verification

[0045] After the baffle 4 is closed, it must completely cover the pipe diameter (assuming the pipe diameter ϕ 600 mm):

[0046] baffle diameter = ϕ650 mm (25 mm sealing allowance is reserved).

[0047] Conclusion: The height H of baffle 4 is 2.1m, which was determined by the energy conversion between the potential energy and kinetic energy of the feed, ensuring that it can "open smoothly and close tightly", thus resolving the contradiction between nitrogen consumption and backfire risk.

[0048] In a preferred embodiment of this invention, the connecting plate 6 is L-shaped.

[0049] In a preferred embodiment of this invention, a support rod 9 and a chain buckle 10 are also included. The support rod 9 is positioned above and parallel to the support plate 5 and is fixed to the feed tube 1. One end of the chain buckle 10 is connected to the support rod 9, and the other end is connected to the baffle 4. The chain buckle 10 serves to prevent the baffle 4 from falling and provides secondary protection, and may not be required.

[0050] Furthermore, the number of guide holes 8 is 2-4, and in this embodiment there are 3 guide holes 8. The diameter of the guide holes 8 is 80-180mm, and in this embodiment the diameter of the guide holes 8 is 80mm.

[0051] In this embodiment, the guide hole 8 is 4.6m away from the outlet along the axial direction of the feed pipe 1, and is evenly arranged along the circumference of the feed pipe 1.

[0052] In this embodiment, the optimal effect is achieved when the diameter of the guide hole 8 is 80mm and the number of guide holes is 3. The calculation and analysis process is as follows:

[0053] The flue gas must be completely discharged through the guide hole 8 to avoid accumulation inside the pipe, and the following formula must be met:

[0054] (must satisfy N×) ≥ )

[0055] Among them, Q 烟 The value of 0.25 m³ / s represents the flue gas generation rate, and the value of 0.25 m³ / s represents the measured peak flow rate of the refining furnace flue gas.

[0056] Q 单孔 The single-hole discharge capacity is calculated using the following formula:

[0057] =Cd·A· =0.62×0.005× ≈0.085 m³ / s

[0058] Where Cd is the orifice flow coefficient, with a value of 0.62; ΔP is the flue gas pressure difference, i.e., the pressure difference between inside and outside the pipe, with a value of 300 Pa; ρ is the flue gas density (800℃), with a value of 0.33 kg / m³, ρ=ρ0×T0 / T, where ρ0 is the flue gas density under the reference condition (usually taken as the value at 0℃ and 1 atm, unit: kg / m³); T0 is the reference absolute temperature (T0=273 K), and T is the actual absolute temperature of the flue gas (unit: K, T=t+273, where t is the temperature in degrees Celsius ℃).

[0059] Minimum number of holes: = / =0.25 / 0.085≈2.94, therefore we take 3.

[0060] After testing and verification, it was found that when there are 2 flow guide holes, the flue gas discharge is insufficient, the positive pressure inside the pipe increases, and the risk of backfire increases; when there are 3 flow guide holes, the flue gas generation is dynamically matched to achieve the best balance; when there are 4 flow guide holes, cold air is drawn in, the furnace temperature fluctuates by ±20℃, and the over-emission occurs.

[0061] In this embodiment, the guide holes 8 are evenly arranged in three positions on the circumference at a distance of 4.6m from the outlet of the feed pipe 1 to avoid airflow interference. The selection of this position is based on the following criteria:

[0062] H1=L·sinθ=6×sin50°≈4.6 m,

[0063] The selection of the 50° tilt angle θ is based on the following:

[0064] Flue gas movement characteristics:

[0065] When high-temperature flue gas rises naturally, it forms a spiral vortex (Coanda effect), and the angle between its mainstream trajectory and the horizontal plane is:

[0066] θ=90°-arctan(gD² / 4νV)≈50°

[0067] Where g = 9.8 m / s 2 Pipe diameter D = 0.6 m, viscosity ν = 1.5 × 10⁻⁶ m −4 m 2 / s (selected based on the reference value of common flue gas kinematic viscosity), flow velocity V=2.5 m / s.

[0068] After verification, a tilt angle of 30° results in low flow resistance, but it is easy to draw in cold air, which poses a risk of decreased furnace temperature stability; a tilt angle of 50° results in flue gas exhaust efficiency >95%, with no significant risk; a tilt angle of 70° results in vertical airflow, but material is prone to clogging the channels, which poses a risk of increased maintenance frequency.

[0069] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A backfire prevention device for a refining furnace charging system, comprising a feeding pipe, a receiving hopper, and a connecting pipe, wherein the feeding pipe is located above the receiving hopper, and the connecting pipe is connected to the bottom of the receiving hopper, characterized in that: The device includes a baffle, a support plate, a connecting plate, and a pin. The feeding pipe is inclined, and the baffle blocks the outlet of the feeding pipe and is perpendicular to the inlet of the receiving hopper. The bottom of the baffle is 1.95-2.65m away from the bottom of the short-connecting pipe. The upper end of the baffle is fixedly connected to the lower end of the connecting plate. The other end of the connecting plate is hinged to the support plate by a pin. The other end of the support plate is fixed to the feeding pipe and is parallel to the inlet of the receiving hopper. The feeding pipe has multiple guide holes.

2. The anti-backfire device for the refining furnace charging system according to claim 1, characterized in that: The number of guide holes is 2-4.

3. The anti-backfire device for the refining furnace charging system according to claim 1, characterized in that: The diameter of the guide hole is 80-180mm.

4. The anti-backfire device for the refining furnace charging system according to claim 1, characterized in that: The distance between the guide hole and the outlet along the axial direction of the feed pipe is 3.5-5m.

5. The anti-backfire device for the refining furnace charging system according to claim 1, characterized in that: The inclination angle of the feed tube is 30-70°.

6. The anti-backfire device for the refining furnace charging system according to claim 1, characterized in that: It also includes a support rod and a chain buckle. The support rod is located above the support plate and is fixed to the feed tube parallel to the support plate. One end of the chain buckle is connected to the support rod and the other end is connected to the baffle.

7. The anti-backfire device for the refining furnace charging system according to claim 1, characterized in that: The connecting plate is L-shaped.

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