Air distribution type combustor and control method thereof

Abstract

The invention discloses an air distribution type combustor and a control method thereof.The air distribution type combustor is characterized in that a combustion unit comprises a material receiving pipe, an inner pipe body, an outer pipe body and a screw rod, the outlet end of the material receiving pipe is connected with the inlet end of the inner pipe body, the inner pipe body is sleeved with the outer pipe body, and the screw rod is arranged at the position, close to the outlet end, in the inner pipe body; a spiral groove is formed in the surface of the spiral rod in the axial direction of the spiral rod. The air distribution unit comprises an air distribution pipeline and a combustion fan, the end, close to the material receiving pipe, of the outer pipe body is a closed end, an air distribution opening is formed in the radial direction of the end of the outer pipe body and connected with the air distribution pipeline, and the other end of the air distribution pipeline is connected with the combustion fan. The air distribution unit is arranged, the air inlet amount is accurately controlled, external air is introduced into the combustion area through the air distribution opening and the air supply channel, fuel and air are mixed more sufficiently, combustion is more complete, and therefore the carbon deposition phenomenon in the spiral groove of the spiral rod is remarkably reduced, and the problem that in the prior art, the spiral groove is prone to being blocked is solved.

Description

Technical Field

[0001] This invention relates to an air distribution type burner and its control method, belonging to the field of burner technology. Background Technology

[0002] During the open-hearth roasting process, a combustion device is required to load a burner and inject fuel into the roasting furnace through the burner to ensure complete combustion. Only after the products in the furnace meet the physical and chemical requirements of the process can they be sold.

[0003] Existing literature ( CN118959993A A low-NOx burner is disclosed, comprising an inner tube body, an outer tube body, a receiving pipe, and a screw rod. The outer tube body is fitted over the inner tube body, with its outlet end extending a predetermined distance beyond the outlet end of the inner tube body. The receiving pipe is located at the inlet end of the outer tube body and communicates with the inlet end of the inner tube body. The screw rod is installed at the outlet end of the inner tube body, and its surface has spiral grooves along its length. Fuel entering the inner tube body through the receiving pipe is spirally guided by the spiral grooves as it passes through the screw rod, and collides with the outlet end of the outer tube body after being ejected. This helps to disperse the fuel, resulting in more complete combustion, a dispersed flame, and reduced localized high temperatures, thereby reducing energy consumption and NOx levels.

[0004] The aforementioned low-NOx burner is a product developed by the applicant. However, during actual production, the applicant discovered that it still has the following problems: the spiral groove of the screw rod is prone to blockage after about 2 months of use. Upon disassembly, it was found that there is a lot of carbon deposits in the spiral groove. Summary of the Invention

[0005] Based on the above, the present invention provides an air distribution type burner and its control method to overcome the shortcomings of the prior art.

[0006] The technical solution of this invention is:

[0007] In a first aspect, the present invention provides an air-distribution burner, comprising:

[0008] The combustion unit includes a receiving pipe, an inner tube, an outer tube, and a screw rod. The outlet end of the receiving pipe is connected to the inlet end of the inner tube. The outer tube is sleeved outside the inner tube. The screw rod is located inside the inner tube near its outlet end, and the surface of the screw rod is provided with a spiral groove along its axial direction.

[0009] The air distribution unit includes an air distribution duct and a combustion-supporting fan. The end of the outer pipe near the receiving pipe is a closed end, and an air distribution port is radially opened on the outer pipe at this end and connected to the air distribution duct. The other end of the air distribution duct is connected to the combustion-supporting fan. A predetermined space exists between the inner ring surface of the outer pipe and the outer ring surface of the inner pipe as an air supply channel.

[0010] In one example, a connection component is also included, which comprises:

[0011] The upper chuck has a connection port, which includes an upper connection port and a lower connection port respectively disposed on the upper part and the bottom of the upper chuck. The upper connection port is threaded to the bottom end of the receiving tube, and the lower connection port is threaded to the top end of the inner tube.

[0012] The lower chuck has an interlocking interface, and the top of the outer tube body has an annular protrusion that is attached to the interlocking interface. The lower chuck and the upper chuck are connected by bolts after being engaged.

[0013] The air distribution port is located on the upper neck portion of the upper chuck, and multiple air distribution ports are evenly distributed along the circumference of the upper neck portion of the upper chuck.

[0014] In one example, a sealing ring is placed inside the joint, and the top and bottom surfaces of the sealing ring are in close contact with the bottom surface of the upper chuck and the top surface of the outer tube, respectively.

[0015] In one example, the outer tube is made of silicon carbide.

[0016] Secondly, the present invention provides a control method for the aforementioned low-NOx burner, comprising the following steps:

[0017] S1 obtains the fuel flow rate and ambient temperature of the feed pipe;

[0018] S2 calculates the basic air intake volume based on the fuel flow rate and the ambient temperature;

[0019] S3 sets the pulse modulation parameters, which include pulse frequency and amplitude;

[0020] S4 generates a modulated air intake signal based on the pulse modulation parameters;

[0021] S5 outputs the modulated air intake signal to the combustion fan controller to control the combustion fan to perform pulsed air intake;

[0022] S6 monitors combustion efficiency in real time;

[0023] S7 adjusts the pulse modulation parameters based on the combustion efficiency;

[0024] S8 repeats steps S4 to S7 at predetermined time intervals.

[0025] The beneficial effects of this invention are:

[0026] 1. By setting up an air distribution unit, precise distribution of the air required for combustion can be achieved, allowing fuel and air to mix fully in the combustion zone and improving combustion efficiency. The design of multiple air distribution ports evenly distributed around the circumference of the upper neck of the upper chuck in the air distribution unit allows airflow to enter the combustion channel evenly, avoiding local oxygen deficiency or excess, and reducing pollutant emissions from incomplete combustion.

[0027] 2. By employing a pulsed air intake control method, including steps such as acquiring fuel flow rate and ambient temperature, calculating basic air intake volume, setting pulse modulation parameters, generating modulation signals, controlling air intake, monitoring efficiency, adjusting parameters, and repeating the process, this invention directly improves the uniformity of fuel-air mixing. Compared to continuous air intake, pulsed air intake enhances turbulence effects, reduces the risk of carbon buildup in the spiral groove, thereby lowering maintenance costs and downtime. Attached Figure Description

[0028] Figure 1 This is a front view of the overall structure of the present invention;

[0029] Figure 2 This is a top view of the overall structure of the present invention;

[0030] Figure 3 This is a structural cross-sectional view of the overall structure of the present invention, taken from the front view.

[0031] Figure 4 for Figure 3 Enlarged view of section A in the middle;

[0032] Figure 5 for Figure 3 Enlarged view of section B;

[0033] In the diagram: Inner tube 1, outer tube 2, receiving pipe 3, screw rod 4, upper chuck 5, connecting port 6, upper connecting port 7, lower connecting port 8, lower chuck 9, overlapping joint 10, bolt 11, sealing ring 12, air outlet 13, air distribution pipe 14. Detailed Implementation

[0034] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Example 1: An air-distribution type burner

[0036] Please see Figures 1 to 5 This embodiment provides an air-distribution burner, which includes a combustion unit and an air distribution unit.

[0037] The combustion unit includes an inner tube 1, an outer tube 2, a receiving pipe 3, and a spiral rod 4. The outer tube 2 is fitted outside the inner tube 1, and the outlet end of the outer tube 2 extends beyond the outlet end of the inner tube 1 by a certain distance. The receiving pipe 3 is installed at the inlet end of the outer tube 2 and is connected to the inlet end of the inner tube 1 to guide fuel into the inner tube 1. The spiral rod 4 is installed at the outlet end of the inner tube 1, and the surface of the spiral rod 4 has multiple spiral grooves along its length. These spiral grooves connect the outlet end of the inner tube 1 and the outlet end of the outer tube 2. The spiral grooves are spiral trajectories. After the fuel is sprayed out through the spiral grooves, it will be swirled, forming a dispersed flow, and will collide with the inner wall of the outer tube, resulting in further diffusion.

[0038] The air distribution unit includes an air distribution duct 14 and a combustion-supporting fan. The end of the outer pipe 2 near the receiving pipe 3 is a closed end, and multiple air distribution ports 13 are opened radially at this end of the outer pipe 2 and connected to the air distribution duct 14. The other end of the air distribution duct 14 is connected to the combustion-supporting fan. There is a predetermined space between the inner ring surface of the outer pipe 2 and the outer ring surface of the inner pipe 1 as an air supply channel, so that the combustion-supporting fan can introduce external air through the air distribution duct 14 and the air supply channel to the bottom of the inner pipe 1.

[0039] During use, fuel enters the inner tube 1 through the receiving pipe 3. Then, as it passes through the spiral rod 4, the fuel is diverted to the outlet edge of the outer tube 2 by the flow-diverting effect of the spiral groove. After the fuel is spirally thrown out from the outlet of the inner tube 1, it collides with the inner wall of the outer tube 2, which helps to scatter the fuel. At the same time, the air intake is precisely controlled so that outside air is introduced into the lower part of the inner tube 1 through the air distribution port 13 and the air supply channel to participate in combustion, making the combustion more complete and avoiding the generation of carbon deposits.

[0040] In addition, compared with the original low-NOx burner scheme, this burner eliminates the flow divider and connecting shaft, further increasing the feed space and ensuring fuel supply. Combined with the addition of air distribution port 13, it can supply higher temperatures and greater heat.

[0041] In one example, the burner also includes a connecting assembly comprising an upper chuck 5 and a lower chuck 9. The upper chuck 5 has a connecting port 6, which includes an upper connecting port 7 and a lower connecting port 8 respectively connected to the upper and bottom of the upper chuck 5. The upper connecting port 7 is threaded to the bottom end of the receiving pipe 3, and the lower connecting port 8 is threaded to the top end of the inner tube 1. The lower chuck 9 has an overlapping interface 10, and the top end of the outer tube 2 is annularly protruding and hooked onto the overlapping interface 10. The lower chuck 9 and the upper chuck 5 are connected by multiple bolts 11 after being engaged. Air distribution ports 13 are opened on the upper neck portion of the upper chuck 5, and two air distribution ports 13 are evenly distributed along the circumference of the upper neck portion of the upper chuck 5.

[0042] The upper chuck 5 and lower chuck 9 are detachable by clamping and fixing with bolts 11. The connection between the upper connecting port 7 and the bottom of the receiving pipe 3 and the connection between the lower connecting port 8 and the top of the inner tube 1 are both threaded connections, making the inner tube 1 easy to disassemble. The outer tube 2 is clamped and positioned by the upper chuck 5 and lower chuck 9. When the upper chuck 5 and lower chuck 9 are disassembled, the outer tube 2 is automatically disassembled, achieving structural optimization and allowing for tiered disassembly and assembly. Replacement is convenient, and tiered disassembly and maintenance can be performed, which helps avoid the need for complete replacement and thus reduces maintenance costs.

[0043] In one example, a sealing ring 12 is placed inside the joint 10, and the top and bottom surfaces of the sealing ring 12 are in close contact with the bottom surface of the upper chuck 5 and the top surface of the outer tube 2, respectively.

[0044] By setting the sealing ring 12, the gap between the upper chuck 5 and the lower chuck 9 is sealed, which helps to prevent fuel leakage.

[0045] In one example, the outer tube 2 is made of silicon carbide. Silicon carbide outer tube 2 is more heat-resistant and provides better protection for the inner tube 1. Compared to traditional burners, the low-NOx burner can be inserted deeper during use.

[0046] Example 2: A control method for an air-distribution burner

[0047] The control method includes the following steps:

[0048] Step S1: Obtain the fuel flow rate and ambient temperature from receiving pipe 3.

[0049] Fuel flow rate is obtained through sensors. (Unit: m³ / s) and ambient temperature (Unit: °C). The fuel flow sensor is installed at the inlet of feed pipe 3, and the ambient temperature sensor is located near the burner to reflect the actual operating conditions.

[0050] Step S2: Calculate the basic intake air volume based on fuel flow rate and ambient temperature.

[0051] Basic air intake Calculated using the following formula:

[0052]

[0053] in:

[0054] It is the wind-fuel ratio coefficient, which is set to 1.2 in this embodiment.

[0055] It is the temperature compensation coefficient, which is set to 0.005 in this embodiment to compensate for the effect of changes in ambient temperature on air density.

[0056] This is the reference temperature, set to 20°C, representing standard operating conditions.

[0057] Step S3: Set the pulse modulation parameters, which include pulse frequency and amplitude.

[0058] The pulse modulation parameters include pulse frequency (f) (unit: Hz) and amplitude (A) (unit: m³ / s). An initial pulse modulation parameter can be set based on historical combustion conditions.

[0059] Step S4: Generate a modulated air intake signal based on the pulse modulation parameters.

[0060] Modulate air intake signal It is generated by combining the base air intake volume with the modulation amount. The modulation amount is based on the pulse frequency and amplitude, and is in square wave form:

[0061]

[0062] in, The function returns 1 or -1, creating a rectangular wave.

[0063] Step S5: Output the modulated air intake signal to the combustion fan controller to control the combustion fan to perform pulsed air intake.

[0064] Modulation signal The signal is sent to the combustion fan controller via a digital-to-analog converter (DAC) or PWM output module. The controller adjusts the fan speed or damper opening to achieve pulsed air intake. The intake air enters the combustion zone through the air distribution duct 14 and the air supply channel, where it mixes with the fuel.

[0065] Step S6: Real-time monitoring of combustion efficiency

[0066] Combustion efficiency Efficiency is estimated by detecting combustion temperature and carbon monoxide (CO) concentration. The combustion temperature sensor is located at the outlet of the outer tube 2, and the CO sensor is located at the flue gas emission port. The efficiency estimation formula is:

[0067]

[0068] Step S7: Adjust the pulse modulation parameters based on the combustion efficiency.

[0069] Adjust based on current combustion efficiency With target combustion efficiency error :

[0070]

[0071] Then, the pulse frequency and amplitude are adjusted using the gradient descent method:

[0072]

[0073] in, and This is the learning rate, which is set to 0.1 in this embodiment, based on the system response characteristics. Adjustments are made gradually to reduce the error, avoiding abrupt changes.

[0074] Step S8: Repeat steps S4 to S7 at predetermined time intervals.

[0075] The repetition interval is set to 0.05 seconds (i.e., 20 Hz) and is triggered by a timer interrupt.

[0076] During actual combustion, the applicant found that continuous air intake by the combustion fan could lead to uneven mixing of fuel and air, increasing the risk of carbon buildup in the spiral grooves and reducing combustion efficiency. Pulsed air intake directly improved the uniformity of fuel-air mixing. Compared to continuous air intake, pulsed air intake enhanced turbulence, reduced the risk of carbon buildup in the spiral grooves, and thus lowered maintenance costs and downtime.

[0077] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An air-distribution type burner, characterized in that, include: The combustion unit includes a receiving pipe, an inner tube, an outer tube, and a screw rod. The outlet end of the receiving pipe is connected to the inlet end of the inner tube. The outer tube is sleeved outside the inner tube. The screw rod is located inside the inner tube near its outlet end, and the surface of the screw rod is provided with a spiral groove along its axial direction. The air distribution unit includes an air distribution duct and a combustion-supporting fan. The end of the outer pipe near the receiving pipe is a closed end, and an air distribution port is radially opened on the outer pipe at this end and connected to the air distribution duct. The other end of the air distribution duct is connected to the combustion-supporting fan. A predetermined space exists between the inner ring surface of the outer pipe and the outer ring surface of the inner pipe as an air supply channel.

2. The air-distribution burner according to claim 1, characterized in that, It also includes a connection component, the connection component comprising: The upper chuck has a connection port, which includes an upper connection port and a lower connection port respectively disposed on the upper part and the bottom of the upper chuck. The upper connection port is threaded to the bottom end of the receiving tube, and the lower connection port is threaded to the top end of the inner tube. The lower chuck has an interlocking interface, and the top of the outer tube body has an annular protrusion that is attached to the interlocking interface. The lower chuck and the upper chuck are connected by bolts after being engaged. The air distribution port is located on the upper neck portion of the upper chuck, and multiple air distribution ports are evenly distributed along the circumference of the upper neck portion of the upper chuck.

3. The low-NOx burner according to claim 2, characterized in that, A sealing ring is placed inside the joint, and the top and bottom surfaces of the sealing ring are in close contact with the bottom surface of the upper chuck and the top surface of the outer tube, respectively.

4. The low-NOx burner according to claim 1, characterized in that, The outer tube is made of silicon carbide.

5. The control method for the low-NOx burner according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1 obtains the fuel flow rate and ambient temperature of the feed pipe; S2 calculates the basic air intake volume based on the fuel flow rate and the ambient temperature; S3 sets the pulse modulation parameters, which include pulse frequency and amplitude; S4 generates a modulated air intake signal based on the pulse modulation parameters; S5 outputs the modulated air intake signal to the combustion fan controller to control the combustion fan to perform pulsed air intake; S6 monitors combustion efficiency in real time; S7 adjusts the pulse modulation parameters based on the combustion efficiency; S8 repeats steps S4 to S7 at predetermined time intervals.

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