Dielectric barrier discharge combustion-supporting low-NOx burner with variable discharge gap
Through the dielectric barrier discharge combustion-assist burner with variable discharge gap, the discharge gap and electric field strength are adjusted, and the problems of poor combustion stability of ammonia fuel and high NOx emissions are solved, achieving low energy consumption and high efficiency ammonia combustion effect.
Patent Information
- Application Number
- CN202510634412.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-16
- Publication Date
- 2025-08-01
AI Technical Summary
During the combustion process of existing ammonia fuel, there are problems such as poor combustion stability, high concentration NOx emissions, and excessive breakdown voltage during dielectric barrier discharge (DBD) and uncontrollable electron energy deposition distribution.
A dielectric barrier discharge combustion-assist burner with variable discharge gap is adopted to adjust the discharge gap of the dielectric barrier discharge module, control the gas breakdown voltage and electric field strength, optimize the ionization reaction path, and suppress NOx generation, including a combination design of the ammonia-air intake premix module, an adjustable discharge gap dielectric barrier discharge module and a cyclone combustion module.
Significantly improve the stability and environmental protection performance of ammonia fuel combustion, reduce energy consumption, optimize the ionization reaction path, and inhibit NOx generation.
Smart Images
Figure CN120402892A_ABST
Abstract
Description
(1) Technical Field
[0001] The present invention belongs to the technical field of ammonia combustion equipment, and specifically relates to a low-NO x swirl burner with DBD (dielectric barrier discharge) combustion assistance using an adjustable discharge gap. (2) Background Art
[0002] As a carbon-free hydrogen-carrying fuel, ammonia's complete combustion products are nitrogen and water, without generating carbon dioxide. Since ammonia is easy to liquefy and the existing production, storage, and transportation systems are relatively complete, it is regarded as a new type of green fuel with application potential and has important strategic significance in achieving carbon dioxide emissions reduction. However, under the existing technical conditions, the ammonia fuel combustion process still faces technical bottlenecks such as poor combustion stability, low flame propagation speed, difficult ignition, and high NO x emissions, which severely restrict the large-scale popularization and application of ammonia fuel.
[0003] Plasma combustion assistance technology is a new type of efficient fuel combustion assistance method. Among them, dielectric barrier discharge (DBD) plasma belongs to typical low-temperature plasma, with a low thermal effect but showing significant non-equilibrium kinetic effects, which can effectively change the chemical reaction path. Applying this technology to the ammonia fuel combustion process can significantly improve problems such as slow ammonia combustion flame propagation speed and difficult ignition. The electric field strength during the discharge process directly affects the electron energy deposition distribution, thereby regulating the reaction mechanism and affecting the generation amount of NO x . Therefore, a dielectric barrier discharge device with an adjustable discharge gap is required to optimize the plasma combustion assistance reaction conditions, promote the large-scale generation of NH2 radicals, and thus inhibit the formation of NO x . In addition, under the condition of the same input voltage, reducing the discharge gap can lower the gas breakdown voltage and reduce the energy input requirement. In the system, the high-voltage electrode is closely attached to the fixed insulating dielectric layer, the low-voltage electrode is closely attached to the slidable insulating dielectric layer, and the discharge working gas is a premixed gas of ammonia and air. (3) Summary of the Invention
[0004] In order to overcome the deficiencies of poor combustion stability, high-concentration NO x emissions existing in the existing ammonia fuel combustion process, as well as the excessively high breakdown voltage and uncontrollable electron energy deposition distribution during the dielectric barrier discharge (DBD) process, the present invention provides a low-NO x burner with DBD combustion assistance having a variable discharge gap, which effectively improves the combustion performance of ammonia fuel through DBD plasma technology, and controls the gas breakdown voltage and the electric field strength within the discharge gap by adjusting the discharge gap of the dielectric barrier discharge module, thereby reducing energy consumption, optimizing the ionization reaction path, and inhibiting NO xThe generation significantly improves the stability and environmental performance of ammonia fuel combustion.
[0005] The technical solution adopted by the present invention to solve its technical problems is as follows:
[0006] A low-NO burner with dielectric barrier discharge for combustion assistance with variable discharge gap x The burner includes an ammonia-air intake premixing module, an adjustable discharge gap dielectric barrier discharge module, and a swirl combustion module. The output side of the ammonia-air intake premixing module is connected to the input side of the adjustable discharge gap dielectric barrier discharge module, and the output side of the adjustable discharge gap dielectric barrier discharge module is connected to the input side of the swirl combustion module.
[0007] Further, in the ammonia-air intake premixing module, ammonia and air enter the premixing chamber through different inlets. Among them, air is introduced from below, and ammonia enters through a side branch pipe.
[0008] Preferably, the length of the premixing chamber is 100 mm, which helps the full mixing of ammonia and air. Subsequently, the mixed gas enters the dielectric barrier discharge module for discharge to form plasma.
[0009] Still further, the dielectric barrier discharge module adopts a double-plate discharge structure, including an inlet pipe, a discharge assembly, and an outlet pipe. The discharge assembly is located in the middle and is respectively connected to the inlet pipe and the outlet pipe. The discharge assembly includes a high-voltage electrode, a box-shaped fixed insulating dielectric layer, a flat insulating dielectric layer slider, and a low-voltage electrode. The high-voltage electrode is closely attached to the outside of the box-shaped fixed insulating dielectric layer, the low-voltage electrode is closely attached to the outside of the flat insulating dielectric layer slider, and the flat insulating dielectric layer slider and the box-shaped fixed insulating dielectric layer are in clearance fit. Raw tape is wrapped and lubricant is coated at the fitting part to ensure sealing. The flat insulating dielectric layer slider can slide horizontally in the cavity of the box-shaped fixed insulating dielectric layer.
[0010] A cuboid-shaped blocking block is fixed inside the box-shaped fixed insulating dielectric layer, which can prevent the flat insulating dielectric layer from sliding inward excessively and falling into the premixing chamber.
[0011] The inlet pipe is a cylindrical inlet pipe, the outlet pipe is a cylindrical outlet pipe, and the discharge assembly is connected to the cylindrical inlet pipe and the cylindrical outlet pipe through a square-round transition section;
[0012] The high-voltage electrode and the low-voltage electrode are both copper sheets, the insulating dielectric is quartz glass, and the rest are all high-temperature resistant stainless steel alloys.
[0013] The thickness of the box-shaped fixed insulating dielectric layer is 1 mm, and the thickness of the slidable flat insulating dielectric layer slider is 1.5 mm. The slidable insulating dielectric layer slider can slide horizontally in the cavity, and the adjusted discharge gap range is from 1.4 mm to 3.5 mm.
[0014] In the swirl combustion module, the swirler adopts a vane type structure, the number of vanes is 8 to 12, the vane thickness is 0.4 mm to 1 mm, and the swirl angle is 45 degrees.
[0015] A groove is arranged on the inner side of the air outlet of the mixed gas channel of the swirl combustion module, and the groove is fixedly connected with the swirler in an interference fit.
[0016] In the present invention, the burner is composed of an ammonia-air intake premixing module, a dielectric barrier discharge module with adjustable gap, and a swirl combustion module. The dielectric barrier discharge module adopts a double-plate dielectric structure, and the discharge gap size is adjusted by adjusting the sliding discharge block to determine the lowest NO x emission discharge gap at the relatively lowest input power of the plasma power supply. Dielectric barrier discharge has a powerful kinetic effect and can generate a large number of active free radicals, excited state molecules and ions. After passing through the swirler, the plasma will generate a swirling motion and carry out swirl combustion.
[0017] The beneficial effects of the present invention are mainly manifested in: reducing energy consumption, optimizing the ionization reaction path, inhibiting the generation of NO x and significantly improving the stability and environmental protection performance of ammonia fuel combustion. (IV) BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 is a schematic structural diagram of the present invention;
[0019] Figure 2 is an axonometric view of the structure of the present invention;
[0020] Figure 3 is an axonometric view of the structure of the dielectric barrier discharge module with adjustable discharge gap of the present invention. (V) SPECIFIC EMBODIMENTS
[0021] The present invention will be further described below with reference to the drawings.
[0022] Referring to Figures 1 to 3 , a low-NO x combustor with variable discharge gap and dielectric barrier discharge for combustion assistance, comprising an ammonia-air intake premixing module 1, a dielectric barrier discharge module 2 with adjustable discharge gap, and a swirl combustion module 3. The output side of the ammonia-air intake premixing module 1 is connected to the input side of the dielectric barrier discharge module 2 with adjustable discharge gap, and the output side of the dielectric barrier discharge module 2 with adjustable discharge gap is connected to the input side of the swirl combustion module 3.
[0023] The dielectric barrier discharge module 2 with adjustable discharge gap adopts a double-plate discharge structure, which includes a cylindrical inlet pipe 4, a square-round transition section 5, a high-voltage electrode 6, a box-shaped fixed insulating dielectric layer 7, a flat insulating dielectric layer slider 8, a low-voltage electrode 9, and a cylindrical outlet pipe 10. A cuboid-shaped blocking block 11 is provided. The discharge assembly with a cuboid shape in the middle is connected to the cylindrical inlet pipe 4 and the cylindrical outlet pipe 10 through the square-round transition section. The high-voltage electrode 6 is a copper sheet closely attached to the outside of the box-shaped fixed insulating dielectric layer 7, and the low-voltage electrode 9 is a copper sheet closely attached to the outside of the flat insulating dielectric layer slider 8. The flat insulating dielectric layer slider 8 is in clearance fit with the box-shaped fixed insulating dielectric layer 7. To ensure the sealing performance, raw tape is wrapped around the fitting part and lubricating oil is coated. The flat insulating dielectric layer slider 8 can slide horizontally in the cavity of the box-shaped fixed insulating dielectric layer 7. Except for the electrodes, all components of the discharge module are made of quartz glass. A cuboid-shaped blocking block 11 is fixed inside the box-shaped fixed insulating dielectric layer 7, which can prevent the flat insulating dielectric layer slider 8 from sliding inward excessively and falling out into the premixing chamber. The ammonia-air premixed gas is ionized in the dielectric barrier discharge region, generating a large number of active free radicals, excited state molecules and ions, reducing NO x emissions.
[0024] The thickness of the box-shaped fixed insulating dielectric layer is 1 mm, and the thickness of the slidable flat insulating dielectric layer slider is 1.5 mm. The slidable insulating dielectric layer slider can slide horizontally in the cavity, and the adjusted discharge gap range is 1.4 mm to 3.5 mm.
[0025] In the swirl combustion module, the swirler adopts a vane type structure, the number of vanes is 8 to 12, the vane thickness is 0.4 mm to 1 mm, and the swirl angle is 45 degrees.
[0026] A groove is provided on the inner side of the air outlet of the mixed gas channel of the swirl combustion module, and the groove is in interference fit with the swirler for fixation.
[0027] The adjustment of the dielectric barrier discharge of the adjustable discharge gap of the burner of the present invention is specifically as follows: ammonia and air are uniformly premixed in the ammonia-air intake premixing module 1, and enter the dielectric barrier discharge module 2 through the cylindrical intake pipe 4. After the plasma power is turned on, the discharge parameters such as voltage, frequency, and power are adjusted, and then the discharge gap is adjusted by sliding the flat insulating dielectric layer slider 8 so that the breakdown voltage can be reached at a lower discharge voltage to form a filamentary discharge. The ammonia and air premixed gas is ionized in the uniform electric field in the double-plate dielectric barrier discharge to generate a plasma containing a large number of active free radicals and electrons, ions, and excited state molecules. In addition, adjusting the discharge gap can change the electron energy distribution and the direction of electron energy deposition. Compared with the non-uniform electrode structure, the adjusted uniform electric field will not generate electrons with excessively high energy, thereby avoiding the N generated by the excitation and dissociation of high-energy electrons and the combination of dissociated O and recombination to form new nitrogen oxides.
[0028] The dielectric barrier discharge combustion-supported ammonia low NO x The burner is adjusted as follows: the ammonia and air premixed gas is ionized by the dielectric barrier discharge module 2 and enters the swirl combustion module 3 through the cylindrical outlet pipe 10, passes through the blades to form a swirl, and performs swirl combustion at the burner outlet.
[0029] In this embodiment, the dielectric barrier discharge module 2 adopts a dual-plate dielectric structure. The size of the discharge gap is adjusted by adjusting the slider of the sliding plate insulating dielectric layer, thereby finding the discharge gap that can achieve the lowest NOx emissions when the plasma power input power is the lowest, reducing the voltage required to break down the gas. The dielectric barrier discharge also has a strong kinetic effect, which can generate a large number of active free radicals, excited molecules and ions to change the reaction path, improve the stability of ammonia combustion, and reduce NO x After the plasma passes through the cyclone, a swirl motion is generated, which further undergoes swirl combustion.
[0030] The embodiments of this specification are merely examples of implementations of the invention and are provided for illustrative purposes only. The scope of protection of the present invention should not be considered limited to the specific embodiments described in these embodiments. The scope of protection of the present invention also extends to equivalent technical means that can be conceived by a person of ordinary skill in the art based on the invention.
Claims
1. A low-NO combustion burner with dielectric barrier discharge for variable discharge gap to assist combustion, characterized in that, x It includes an ammonia-air intake premixing module, an adjustable discharge gap dielectric barrier discharge module, and a swirl combustion module. The output side of the ammonia-air intake premixing module is connected to the input side of the adjustable discharge gap dielectric barrier discharge module, and the output side of the adjustable discharge gap dielectric barrier discharge module is connected to the input side of the swirl combustion module.
2. A low-NO combustion burner with dielectric barrier discharge for variable discharge gap and combustion assistance, characterized in that, x In the ammonia-air intake premixing module, ammonia and air enter the premixing chamber through different inlets. Among them, air is introduced from below, and ammonia enters through a side branch pipe. 3. A low-NO combustion burner with dielectric barrier discharge for assisting combustion with a variable discharge gap as claimed in claim 2, characterized in that, x The length of the premixing chamber is 100 mm. 4. A low-NOx burner with dielectric barrier discharge for combustion assistance having a variable discharge gap as claimed in any one of claims 1 to 3, characterized in that, The dielectric barrier discharge module adopts a double-plate discharge structure, including an inlet pipe, a discharge assembly, and an outlet pipe. The discharge assembly is located in the middle and is connected to the inlet pipe and the outlet pipe respectively. The discharge assembly includes a high-voltage electrode, a box-shaped fixed insulating dielectric layer, a sliding block of a flat insulating dielectric layer, and a low-voltage electrode. The high-voltage electrode is closely attached to the outside of the box-shaped fixed insulating dielectric layer, and the low-voltage electrode is closely attached to the outside of the sliding block of the flat insulating dielectric layer. The sliding block of the flat insulating dielectric layer and the box-shaped fixed insulating dielectric layer are in clearance fit. Raw tape is wrapped and lubricant is coated at the fitting part to ensure sealing. The sliding block of the flat insulating dielectric layer can slide horizontally in the cavity of the box-shaped fixed insulating dielectric layer.
5. A low-NO combustion burner with dielectric barrier discharge for variable discharge gap combustion assistance, as claimed in claim 4, characterized in that, x A cuboid-shaped blocking block is fixed inside the box-shaped fixed insulating dielectric layer. 6. A low-NO combustion burner with dielectric barrier discharge for variable discharge gap combustion assistance, as claimed in claim 4, characterized in that x The inlet pipe is a cylindrical inlet pipe, the outlet pipe is a cylindrical outlet pipe, and the discharge assembly is connected to the cylindrical inlet pipe and the cylindrical outlet pipe through a square-round transition section. 7. A low-NO burner with dielectric barrier discharge for combustion assistance having a variable discharge gap as claimed in claim 4, characterized in that, x The high-voltage electrode and the low-voltage electrode are both copper sheets, the insulating dielectric is quartz glass, and the rest are all high-temperature resistant stainless steel alloys.
8. A low-NO combustion burner with dielectric barrier discharge for variable discharge gap combustion assistance, as described in claim 4, characterized in that, x The thickness of the box-shaped fixed insulating dielectric layer is 1 mm, the thickness of the slidable flat insulating dielectric layer sliding block is 1.5 mm, the slidable insulating dielectric layer sliding block can slide horizontally in the cavity, and the adjusted discharge gap range is from 1.4 mm to 3.5 mm. 9. A low-NO combustion burner with dielectric barrier discharge for assisting combustion and having a variable discharge gap as described in any one of claims 1 to 3, characterized in that, x In the swirl combustion module, the swirler adopts a vane type structure, the number of vanes is 8 to 12, the vane thickness is 0.4 mm to 1 mm, and the swirl angle is 45 degrees. 10. A low-NO combustion burner with dielectric barrier discharge for assisting combustion and having a variable discharge gap as claimed in claim 9, characterized in that, x A groove is arranged on the inner side of the gas outlet of the mixed gas channel of the swirl combustion module, and the groove is fixed with the swirler by interference fit.