A device and method for decomposing CO2 by dielectric barrier discharge plasma

Abstract

The present invention belongs to the field of plasma technology, and specifically is a device and method for decomposing CO2 by dielectric barrier discharge plasma, comprising a first end cap, a second end cap and a sleeve; the sleeve is fixedly connected with a circulating water inlet and a circulating water outlet; a honeycomb partition is arranged inside the sleeve; a group of flow openings are opened on the honeycomb partition; a group of quartz tubes are slidably connected inside the honeycomb partition; a group of flow equalizing plates are fixed inside the quartz tube; a group of flow holes are opened on the flow equalizing plates; an electrode placement hole is opened at the center of the flow equalizing plates; a stainless steel rod is slidably connected in the electrode placement hole; a gas inlet pipe is fixedly connected to the left wall of the first end cap; a gas outlet pipe is fixedly connected to the second end cap, so as to solve the problem that when the gas flows through the space between the central electrode and the circulating water electrode, it is easy to have uneven flow, resulting in that some carbon dioxide molecules cannot fully contact the plasma, thus affecting the reaction.

Description

Technical Field

[0001] The invention belongs to the field of plasma technology, and in particular to a device and method for decomposing CO2 by dielectric barrier discharge plasma. Background Art

[0002] Dielectric barrier discharge is another common reactor for treating CO2 gas, which can provide thermodynamic non-equilibrium plasma at room temperature and pressure. Dielectric barrier discharge is an inhomogeneous discharge that requires alternating current to operate. By applying an electric field between two electrodes, the charge is transferred in the electrode-dielectric-gas-electrode (it can also be a double-layer or multi-layer dielectric), and a discharge is generated in the discharge gap.

[0003] In the prior art, the flow and mixing of carbon dioxide gas in a coaxial cylindrical reactor are crucial to the reaction effect. However, due to the structural characteristics of the reactor, the gas is prone to uneven flow when flowing through the space between the central electrode and the circulating water electrode, resulting in some carbon dioxide molecules being unable to fully contact the plasma, affecting the reaction. In addition, the uneven flow of the gas may also lead to uneven distribution of the reaction products in the reactor, increasing the difficulty of product separation and collection. For this reason, the present invention provides a device and method for decomposing CO2 by dielectric barrier discharge plasma. Summary of the invention

[0004] In order to make up for the shortcomings of the existing technology, the problem of uneven flow of gas when flowing through the space between the central electrode and the circulating water electrode is solved, which causes some carbon dioxide molecules to be unable to fully contact the plasma and affect the reaction.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a device for decomposing CO2 by dielectric barrier discharge plasma described in the present invention comprises a first end cap, a second end cap and a sleeve; a circulating water inlet is fixedly connected to the bottom of the sleeve near the left end; a circulating water outlet is fixedly connected to the top of the sleeve near the right end; a honeycomb partition is arranged inside the sleeve; a group of flow openings are opened on the honeycomb partition; a group of quartz tubes are slidably connected inside the honeycomb partition; a group of equalizing plates are fixedly connected inside the quartz tube; a group of flow holes are opened on the equalizing plate; an electrode placement hole is opened at the center of the equalizing plate; a stainless steel rod is slidably connected to the electrode placement hole; a limiting ring is fixedly connected to the outer wall of the quartz tube near the left end; a limiting mechanism is slidably connected to the left end of the sleeve; the first end cap is located at the left end of the limiting mechanism; a gas inlet pipe is fixedly connected to the center of the left side wall of the first end cap; a gas dispersion mechanism is arranged inside the first end cap; the second end cap is slidably connected to the right end of the sleeve; and a gas outlet pipe is fixedly connected to the second end cap.

[0006] Preferably, the limiting mechanism includes a baffle plate; a group of first limiting frames are fixedly connected to the right side wall of the baffle plate, and the first limiting frame is adapted to the left end of the quartz tube; the right side wall of the first limiting frame is fixedly connected to the limiting plate; a group of fixing grooves are opened on the limiting plate; the limiting ring is adapted to the fixing grooves; a group of electrical limiting grooves and air inlet holes are opened at the corresponding positions of the right side wall of the baffle plate and the first limiting frame.

[0007] Preferably, the air diffusion mechanism includes a central tube, which is fixed to the center position of the inner wall of the first head; a group of dispersion tubes are fixed to the inner wall of the first head, and the dispersion tubes are equidistantly arranged around the central tube; a group of air holes are opened on the tube wall of the dispersion tube; the ends of the central tube and the dispersion tube are sealed; and air diffusion tubes are fixed to the relative positions of the central tube and the outer walls of the dispersion tubes.

[0008] Preferably, a gas collecting plate is fixedly connected inside the second head; a group of gas collecting holes are opened on the gas collecting plate; the positions of the gas collecting holes correspond to the positions of the quartz tubes; a group of second limit frames are fixedly connected to the left side wall of the gas collecting plate, and the second limit frames are adapted to the right end of the quartz tube; a group of electrical limit grooves are opened at positions corresponding to the left side wall of the gas collecting plate and the second limit frame; the second head is hemispherical inside.

[0009] Preferably, the circulating water in the casing serves as a grounding electrode, and the initial temperature of the circulating water is room temperature; the stainless steel rod serves as a high-voltage electrode.

[0010] Preferably, the inner diameter of the right end of the quartz tube in the non-working area is smaller than that of the left end of the quartz tube.

[0011] Preferably, the first end cap, the limiting mechanism and the sleeve are fastened together by a group of bolts; and the second end cap and the sleeve are fastened together by a group of bolts.

[0012] Preferably, a group of gasket grooves are opened on the side wall of the right end of the sleeve; a rubber gasket is slidably connected in the gasket groove; and the rubber gasket is adapted to the right end body of the quartz tube.

[0013] A method for decomposing CO2 by dielectric barrier discharge plasma, applicable to the above-mentioned device for decomposing CO2 by dielectric barrier discharge plasma, comprises the following steps:

[0014] Step S1: After circulating water is introduced and the circulating water starts to circulate, the power is turned on to generate plasma between the high-voltage electrode stainless steel rod and the circulating water;

[0015] Step S2: introducing CO2 gas, which enters all quartz tubes under the action of the gas diffusion mechanism, and decomposes into CO and O2 under the action of plasma;

[0016] Step S3: The decomposed mixed gas enters the second end cap under the action of the gas collecting plate and the gas collecting holes, and is discharged from the gas outlet pipe.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The device and method for decomposing CO2 by dielectric barrier discharge plasma described in the present invention slightly blocks and diverts the gas entering the plasma working area by setting a flow equalizing plate and a diversion hole, so that the incoming gas is evenly filled in the plasma working area, which enables CO2 to fully contact and decompose with the plasma, thereby improving the CO2 conversion rate.

[0019] 2. The device and method for decomposing CO2 by dielectric barrier discharge plasma described in the present invention can prevent the circulating water in the device from leaking at the left end of the casing by fastening the fixing groove and the limiting ring under the action of bolts, and can prevent the circulating water in the device from leaking at the right end of the casing by fastening the gasket groove and the rubber gasket under the action of bolts.

[0020] 3. The device and method for decomposing CO2 by dielectric barrier discharge plasma described in the present invention use circulating water as the grounding electrode, which can effectively reduce the temperature of the interlayer, reduce the reverse reaction of the CO2 decomposition reaction, and improve the CO2 conversion rate.

[0021] 4. The device and method for decomposing CO2 by dielectric barrier discharge plasma described in the present invention can separate circulating water by setting up honeycomb partitions, thereby preventing the circulating water from touching different quartz tubes during operation, causing unstable flow direction and flow velocity, increasing internal disturbances of the fluid, interfering with the stability of the electric field, and thus weakening plasma discharge.

[0022] 5. In the device and method for decomposing CO2 by dielectric barrier discharge plasma described in the present invention, the quartz tube and the stainless steel rod are both slidably connected in the device, and the quartz tube and the stainless steel rod are only fixed by the limit device and the tightening action of bolts, which is convenient for maintenance and replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] Figure 1 is a stereogram of the present invention;

[0025] Figure 2 is a side cross-sectional view of the present invention;

[0026] Figure 3 It is a partial structural diagram and a partial exploded diagram of the right end of the casing;

[0027] Figure 4 This is an exploded view of the left end of the casing;

[0028] Figure 5 It is the structural diagram of the first head;

[0029] Figure 6 It is the structural diagram of the limit mechanism;

[0030] Figure 7 This is the structural diagram of the second head;

[0031] Figure 8 is a side cross-sectional view of the casing;

[0032] Fig. 9 This is a partial structural diagram of a quartz tube;

[0033] Fig.10 This is the structural diagram of the current equalizing plate.

[0034] In the figure: 1. sleeve; 11. circulating water inlet; 12. circulating water outlet; 13. honeycomb partition; 131. flow port; 14. gasket groove; 2. first end cap; 21. gas inlet pipe; 22. center pipe; 23. dispersion pipe; 24. dispersion pipe; 25. gas distribution hole; 3. second end cap; 31. gas outlet pipe; 32. gas collecting plate; 33. second limit frame; 34. gas collecting hole; 4. quartz tube; 41. flow equalizing plate; 411. electrode placement hole; 412. flow distribution hole; 42. limit ring; 5. stainless steel rod; 6. baffle; 61. first limit frame; 62. electrode limit groove; 63. gas inlet hole; 7. limit plate; 71. fixing groove; 8. rubber gasket. DETAILED DESCRIPTION

[0035] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0036] Embodiment 1

[0037] like Figure 1 to Figure 2 , Figures 4 to 10As shown, a device for decomposing CO2 by dielectric barrier discharge plasma according to an embodiment of the present invention comprises a first end cap 2, a second end cap 3 and a sleeve 1, wherein a circulating water inlet 11 is fixedly connected to the bottom of the sleeve 1 near the left end; a circulating water outlet 12 is fixedly connected to the top of the sleeve 1 near the right end; a honeycomb partition 13 is provided inside the sleeve 1; a group of flow openings 131 are opened on the honeycomb partition 13; a group of quartz tubes 4 are slidably connected inside the honeycomb partition 13; a group of equalizing plates 41 are fixedly connected inside the quartz tube 4; and a group of equalizing plates 41 are provided on the equalizing plates 41. A group of flow holes 412 are provided; an electrode placement hole 411 is provided at the center of the flow balancing plate 41; a stainless steel rod 5 is slidably connected in the electrode placement hole 411; a limiting ring 42 is fixedly connected to the outer wall of the quartz tube 4 near the left end; a limiting mechanism is slidably connected to the left end of the sleeve 1; the first end cap 2 is located at the left end of the limiting mechanism; a gas inlet pipe 21 is fixedly connected to the center of the left side wall of the first end cap 2; a gas dispersion mechanism is provided in the first end cap 2; the second end cap 3 is slidably connected to the right end of the sleeve 1; a gas outlet pipe 31 is fixedly connected to the second end cap 3.

[0038] Furthermore, the honeycomb partition 13 can be made of insulating material, and a flow port 131 is set to form three flow routes. One route is from the bottom partition to the left partition and then to the top partition, one route is from the bottom partition to the center partition and then to the top partition, and the last route is from the bottom partition to the right partition and then to the top partition. The three flow routes start to circulate circulating water at the same time.

[0039] The limiting mechanism includes a baffle plate 6; a group of first limiting frames 61 are fixedly connected to the right side wall of the baffle plate 6, and the first limiting frame 61 is adapted to the left end of the quartz tube 4; the right side wall of the first limiting frame 61 is fixedly connected to the limiting plate 7; a group of fixing grooves 71 are opened on the limiting plate 7; the limiting ring 42 is adapted to the fixing grooves 71; a group of electrical limiting grooves 62 and air inlet holes 63 are opened at the corresponding positions of the right side wall of the baffle plate 6 and the first limiting frame 61.

[0040] The gas diffusion mechanism includes a central tube 22, which is fixed to the center position of the inner wall of the first head 2; a group of dispersion tubes 23 are fixed to the inner wall of the first head 2, and the dispersion tubes 23 are equidistant around the central tube 22; a group of air holes 25 are opened on the tube wall of the dispersion tube 23; the ends of the central tube 22 and the dispersion tubes 23 are both sealed; and a gas diffusion tube 24 is fixed to the relative position of the outer wall of the central tube 22 and the dispersion tube 23.

[0041] A gas collecting plate 32 is fixedly connected inside the second head 3; a group of gas collecting holes 34 are opened on the gas collecting plate 32; the positions of the gas collecting holes 34 correspond to the positions of the quartz tube 4; a group of second limit frames 33 are fixedly connected to the left side wall of the gas collecting plate 32, and the second limit frame 33 is adapted to the right end of the quartz tube 4; a group of electrical limit grooves 62 are opened at the left side wall of the gas collecting plate 32 corresponding to the second limit frame 33; the second head 3 is hemispherical inside.

[0042] The circulating water in the casing 1 serves as a grounding electrode, and the initial temperature of the circulating water is room temperature; the stainless steel rod 5 serves as a high-voltage electrode.

[0043] The inner diameter of the right end of the quartz tube 4 in the non-working area is smaller than that of the left end of the quartz tube 4 .

[0044] The first end cap 2, the limiting mechanism and the sleeve 1 are fastened together by a group of bolts; the second end cap 3 and the sleeve 1 are fastened together by a group of bolts. When the quartz tube 4 is slidably connected in the sleeve 1 during operation, the limiting ring 42 can limit the position of the quartz tube 4, and the cooperation and compression with the fixing groove 71 can prevent the circulating water from leaking at the connection. The first limiting frame 61 cooperates with the left end of the quartz tube 4 to prevent the gas from leaking at the connection. The electric limiting groove 62 on the baffle plate 6 can limit the position of the stainless steel rod 5 at the left end of the sleeve. The circulating water enters the sleeve 1 from the circulating water inlet 11, enters into different compartments separated by the honeycomb partition 13 through the flow port 131, and finally gathers and is sent out at the circulating water outlet 12 for circulation. The gas enters through the gas inlet pipe 21 and is dispersed to each stone by the gas dispersion mechanism. In the interlayer between the quartz tube 4 and the stainless steel rod 5, the incoming gas is more evenly filled and circulated in the interlayer under the action of the flow equalizing plate 41 and the diverter hole 412, the plasma generated in the interlayer decomposes the incoming gas, and the decomposed mixed gas is sent out through the gas outlet pipe 31, and after the gas enters the central tube 22 from the gas inlet pipe 21, under the action of the seal, the gas can only enter each dispersion tube 23 through the gas diffusion pipe 24, and then be evenly dispersed into the first head 2 through the gas diverter hole 25, the second limit frame 33 cooperates with the right end of the quartz tube 4 to prevent gas leakage, the electrical limit groove 62 on the gas collecting plate 32 can limit the position of the stainless steel rod 5 at the right end, the gas collecting plate 32 and the hemispherical second head 3 can make it easier for the gas to flow out, and it is not easy for the backflow to disrupt the uniform distribution and flow of the gas in the quartz tube 4.

[0045] Embodiment 2

[0046] like Figure 1 , Figure 3 and Figure 7As shown, on the basis of the first embodiment, a group of gasket grooves 14 are opened on the side wall of the right end of the sleeve 1; a rubber gasket 8 is slidably connected in the gasket groove 14; the rubber gasket 8 is adapted to the right end body of the quartz tube 4. When working, under the tightening of the bolts, the second limit frame 33 exerts a compression effect on the rubber gasket 8, so that the rubber gasket 8 fits tightly to the gasket groove 14 and the right end body of the quartz tube 4, thereby preventing the circulating water from leaking at the right end body of the sleeve 1.

[0047] A method for decomposing CO2 by dielectric barrier discharge plasma, applicable to the above-mentioned device for decomposing CO2 by dielectric barrier discharge plasma, comprises the following steps:

[0048] Step S1: After circulating water is introduced and the circulating water starts to circulate, the power is turned on to generate plasma between the high-voltage electrode stainless steel rod 5 and the circulating water;

[0049] Step S2: CO2 gas is introduced into all quartz tubes 4 under the action of the gas diffusion mechanism, and the CO2 gas is decomposed into CO and O2 under the action of plasma;

[0050] Step S3: the decomposed mixed gas enters the second end cap 3 under the action of the gas collecting plate 32 and the gas collecting holes 34 , and is discharged from the gas outlet pipe 31 .

[0051] Working principle: The plasma generated between the high-voltage electrode stainless steel rod 5 and the quartz tube 4 decomposes the CO2 gas entering the quartz tube 4 to produce CO and O2. The gas entering the plasma working area is slightly blocked and diverted by setting the flow plate 41 and the diversion hole 412, so that the incoming gas is evenly filled in the plasma working area, which can make CO2 fully contact and decompose with the plasma, thereby improving the CO2 conversion rate. At the same time, the excess heat generated by the device will be taken away by the circulating water, which can effectively reduce the temperature of the interlayer, reduce the reverse reaction of the CO2 decomposition reaction, and improve the CO2 conversion rate.

[0052] The above-mentioned front, back, left, right, top and bottom are all based on the figures in the specification. Figure 1 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0053] In the description of the present invention, it is necessary to understand that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device, method or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0054] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A device for decomposing CO2 by dielectric barrier discharge plasma, characterized in that: The invention comprises a first end cap (2), a second end cap (3) and a sleeve (1); a circulating water inlet (11) is fixedly connected to the bottom of the sleeve (1) near the left end; a circulating water outlet (12) is fixedly connected to the top of the sleeve (1) near the right end; a honeycomb partition (13) is provided inside the sleeve (1); a group of flow openings (131) are provided on the honeycomb partition (13); a group of quartz tubes (4) are slidably connected inside the honeycomb partition (13); a group of flow equalizing plates (41) are fixedly connected inside the quartz tube (4); a group of flow equalizing holes (412) are provided on the flow equalizing plates (41); An electrode placement hole (411) is provided at the center of the flow plate (41); a stainless steel rod (5) is slidably connected in the electrode placement hole (411); a limiting ring (42) is fixedly connected to the outer wall of the quartz tube (4) near the left end; the left end of the sleeve (1) is slidably connected to a limiting mechanism; the first end cap (2) is located at the left end of the limiting mechanism; a gas inlet pipe (21) is fixedly connected to the center of the left side wall of the first end cap (2); a gas dispersion mechanism is provided in the first end cap (2); the second end cap (3) is slidably connected to the right end of the sleeve (1); and a gas outlet pipe (31) is fixedly connected to the second end cap (3).

2. The device for decomposing CO2 by dielectric barrier discharge plasma according to claim 1, characterized in that: The limiting mechanism comprises a baffle plate (6); a first limiting frame (61) is fixedly connected to the right side wall of the baffle plate (6), and the first limiting frame (61) is matched with the left end of the quartz tube (4); the first limiting frame (61) is fixedly connected to the right side wall of the baffle plate (6); a group of fixing grooves (71) are formed on the limiting plate (7); the limiting ring (42) is matched with the fixing grooves (71); a group of electric limiting grooves (62) and air inlet holes (63) are formed at positions corresponding to the right side wall of the baffle plate (6) and the first limiting frame (61).

3. The device for decomposing CO2 by dielectric barrier discharge plasma according to claim 2, characterized in that: The gas diffusion mechanism comprises a central tube (22), the central tube (22) being fixedly connected to the center position of the inner side wall of the first end cap (2); a group of dispersion tubes (23) being fixedly connected to the inner side wall of the first end cap (2), and the dispersion tubes (23) being equidistantly arranged around the central tube (22); a group of air holes (25) being provided on the tube wall of the dispersion tube (23); the ends of the central tube (22) and the dispersion tube (23) are both sealed; and a gas diffusion tube (24) is fixedly connected to the outer walls of the central tube (22) and the dispersion tube (23) at relative positions.

4. The device for decomposing CO2 by dielectric barrier discharge plasma according to claim 3, characterized in that: A gas collecting plate (32) is fixedly connected inside the second end cap (3); a group of gas collecting holes (34) are provided on the gas collecting plate (32); the positions of the gas collecting holes (34) correspond to the positions of the quartz tube (4); a group of second limit frames (33) are fixedly connected to the left side wall of the gas collecting plate (32), and the second limit frames (33) are matched with the right end of the quartz tube (4); a group of electric limit grooves (62) are provided at positions corresponding to the left side wall of the gas collecting plate (32) and the second limit frames (33); the second end cap (3) is hemispherical inside.

5. The device for decomposing CO2 by dielectric barrier discharge plasma according to claim 4, characterized in that: The circulating water in the casing (1) serves as a grounding electrode, and the initial temperature of the circulating water is room temperature; the stainless steel rod (5) serves as a high-voltage electrode.

6. The device for decomposing CO2 by dielectric barrier discharge plasma according to claim 5, characterized in that: The inner diameter of the right end of the quartz tube (4) in the non-working area is smaller than the inner diameter of the left end of the quartz tube (4) in the non-working area.

7. The device for decomposing CO2 by dielectric barrier discharge plasma according to claim 6, characterized in that: The first end cap (2), the limiting mechanism and the sleeve (1) are fastened together by a group of bolts; and the second end cap (3) and the sleeve (1) are fastened together by a group of bolts.

8. The device for decomposing CO2 by dielectric barrier discharge plasma according to claim 7, characterized in that: A group of gasket grooves (14) are formed on the right side wall of the sleeve (1); a rubber gasket (8) is slidably connected in the gasket groove (14); and the rubber gasket (8) is adapted to the right end of the quartz tube (4).

9. A method for decomposing CO2 by dielectric barrier discharge plasma, applicable to the device for decomposing CO2 by dielectric barrier discharge plasma as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1: After circulating water is introduced and the circulating water starts to circulate, the power supply is turned on to generate plasma between the high-voltage electrode stainless steel rod (5) and the circulating water; Step S2: introducing CO2 gas, which enters each quartz tube (4) under the action of the gas diffusion mechanism, and the CO2 gas is decomposed into CO and O2 under the action of plasma; Step S3: The decomposed mixed gas enters the second end cap (3) under the action of the gas collecting plate (32) and the gas collecting hole (34), and is discharged from the gas outlet pipe (31).

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