CN116576692A - Cooling tower for demisting based on nanosecond pulse - Google Patents

Abstract

This application discloses a cooling tower based on nanosecond pulse defogging, which includes a plate electrode and a high voltage electrode, the plate electrode and the high voltage electrode are placed at intervals, and the high voltage electrode is connected with a nanosecond pulse power supply, which is used to generate a strong electric field to make the discharge area The gas is ionized to charge the droplets, and the plate electrode is grounded to collect the charged droplets. It has the following advantages: through the optimization of the electrode structure and power supply form, the droplet charging and condensation capabilities are enhanced, and under the application conditions of large air volume, high wind speed and high humidity, while ensuring the insulation strength, reducing the droplet to the collector The offset distance of the liquid pole improves the efficiency of droplet capture and defogging efficiency, and at the same time avoids the impact of spark discharge on efficiency and safety, and improves the stability and safety of system operation.

Description

A cooling tower for defogging based on nanosecond pulses

technical field

The invention belongs to the technical field of heat exchange equipment, and in particular relates to a cooling tower for defogging based on nanosecond pulses.

Background technique

As an effective cooling equipment, cooling towers are widely used in industrial and agricultural production, especially thermal power plants and nuclear power plants that require a large amount of cooling water. The effect and cooling efficiency requirements are also gradually increasing. In the case of water shortage, the traditional passive cooling tower defogging will cause water loss through evaporation loss, wind blowing loss, sewage loss, etc., so the cooling tower consumes a lot of water. become an urgent problem to be solved.

At present, the active defogging of cooling towers mostly adopts the wire-plate electrode structure in the form of DC high voltage excitation parallel connection. According to the gas breakdown volt-ampere characteristic curve, the corona discharge expected to be required for defogging is high voltage and low current, and the entire gas gap presents a comparatively high voltage. low conductivity. However, due to reasons such as electrode processing and electrode connection process, the discharge is prone to sparks or flashover discharges along the surface, which will produce local high conductivity (good conductor), high current and low electrode gap voltage, which means that in all lines When the electrodes are connected in parallel, once the spark discharge is formed, the instantaneous voltage of all the wire-plate electrode gaps can be reduced to hundreds of volts to tens of volts at the lowest, which will not be enough to maintain the corona discharge, so that the entire system will be in a paralyzed state instantaneously. In addition, the spark discharge is accompanied by a huge current impact, which has a negative impact on the service life of the power supply and equipment. In addition, when the spark discharge occurs, some types of power supplies are in need of self-protection, and the output is suspended for a few tenths to a few seconds, resulting in Reduced fog efficiency.

Contents of the invention

The technical problem to be solved by the present invention is to provide a cooling tower based on nanosecond pulse demisting based on the above deficiencies. Through the optimization of the electrode structure and the power supply form, the droplet charging and condensing capabilities are enhanced, and the cooling tower can be used in large air volumes. , Under the application conditions of high wind speed and high humidity, while ensuring the insulation strength, reduce the offset distance from the liquid droplet to the liquid collector, improve the efficiency of liquid droplet capture, improve the efficiency of defogging, and avoid the impact of spark discharge on efficiency and The impact of security, improve the stability and security of system operation.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

A cooling tower for defogging based on nanosecond pulses, including plate electrodes and high-voltage electrodes, the plate electrodes and high-voltage electrodes are placed at intervals, and the high-voltage electrodes are connected to nanosecond pulse power sources for generating strong electric fields to ionize gas in the discharge area , to charge the droplets, and the plate electrode is grounded for collecting the charged droplets.

Further, the plate electrode includes a flat ground electrode and a shielding tube, the shielding tube is welded to the lower end of the flat ground electrode, an internal welding point is provided at the bottom of the shielding tube, and a water flow groove is formed between the lower part of the flat ground electrode and the shielding tube.

Further, the top of the flat ground electrode adopts an inverted ridge structure, and the included angle ranges from 40° to 90°.

Further, the shielding pipe is a steel pipe with a gap in the upper part, and a water outlet hole is drilled in the lower part of the shielding pipe, and the diameter of the shielding pipe is 25-58 mm.

Further, the shielding tube is installed obliquely, and the inclination angle θ of the shielding tube relative to the flat ground electrode is 3-5 degrees.

Further, the high-voltage electrode includes a high-voltage line electrode and a high-voltage support frame, and the high-voltage line electrode and the high-voltage support frame are fixed together by fastening screws, fastening bolts and fastening nuts.

Further, every 3 high-voltage line electrodes are vertically arranged as a column, 5 columns of high-voltage line electrodes and 5 flat ground electrodes are used as a group of discharge units, and each column of high-voltage line electrodes in each group of discharge cells is spaced from the flat ground electrodes.

Furthermore, each group of discharge units is independently connected to a nanosecond pulse power supply, and the five rows of high-voltage line electrodes are connected to the nanosecond pulse power supply as a series of current-limiting resistors, and the resistance value of the current-limiting resistor is 5-10 kΩ.

Further, the gap between each column of the high-voltage wire electrodes is 100 mm-110 mm.

Further, each group of discharge units has a separate ground wire, and the five flat ground electrodes are connected as a group and then grounded.

The present invention adopts the above technical scheme, and compared with the prior art, it has the following technical effects:

The optimization method of the present invention enhances the charging and condensing ability of the droplets through the optimization of the electrode structure and the form of the power supply, and under the application conditions of large air volume, high wind speed and high humidity, while ensuring the insulation strength, the droplet is reduced The offset distance of the collector improves the droplet capture efficiency. By improving the structure and arrangement of the electrodes, the impact of spark discharge on efficiency and safety can be avoided, and the stability and safety of system operation can be improved. Through the development of electrode structures and combinations in different forms and materials, the modular design and manufacturing form are optimized to improve the reliability and economy of electrodes.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the specific embodiments or the prior art. Throughout the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, elements or parts are not necessarily drawn in actual scale.

Fig. 1 is the structural representation of this device;

Fig. 2 and Fig. 3 are the plate electrode optimization schematic diagrams of this device;

Fig. 4 is the fixed schematic diagram of high-voltage electrode of this device;

In the figure: 1-flat ground electrode; 2-shielding tube; 3-water flow tank; 4-internal welding point; 5-high voltage line electrode; 6-fastening screw; 7-high voltage support frame; 8-fastening bolt; 9- Fastening nut; 10-cooling tower; 11-current limiting resistor; 12-nanosecond pulse power supply.

Detailed ways

Embodiment 1, as shown in Figures 1 to 4, a cooling tower based on nanosecond pulse defogging, including a plate electrode and a high-voltage electrode, the plate electrode includes a flat ground electrode 1 and a shielding tube 2, and the flat ground electrode 1 The top adopts an inverted ridge structure with an angle range of 40°-90°, and a water flow groove 3 is formed between the lower part of the flat ground electrode 1 and the shielding tube 2. The advantage of this structure is that it is better than the traditional flat electrode structure It can collect condensed droplets more efficiently and improve water collection efficiency.

The shielding tube 2 is welded to the lower end of the flat ground electrode 1, and an internal welding point 4 is provided at the bottom of the shielding tube 2. The diameter range of the shielding tube 2 is 25-58 mm. Compared with the direct flat structure, the design of the shielding tube 2 prevents the flat plate The breakdown of the lower edge of the ground electrode 1 suppresses the generation of spark discharge. The shielding tube 2 is installed at a certain inclination angle, and the liquid droplets will flow downward along the inclined shielding tube 2. The inclination angle θ is 3-5 degrees, and a certain number of water outlet holes are drilled in the lower part of the shielding tube 2 to form a screen structure to prevent the gas carrying liquid droplets from escaping from the active demisting space, and to collect liquid droplets to the maximum extent.

The high-voltage electrode includes a high-voltage wire electrode 5 and a high-voltage support frame 7. The high-voltage wire electrode 5 and the high-voltage support frame 7 are fixed together by fastening screws 6, fastening bolts 8 and fastening nuts 9. The high-voltage wire electrode 5 is straightened, Tightening and straightening of the high-voltage line electrode 5 can avoid uneven discharge or even partial breakdown caused by bending and sharp protrusions. The diameter of the high-voltage line electrode 5 is 1mm.

Every three high-voltage wire electrodes 5 are vertically arranged as a row, and five rows of high-voltage wire electrodes 5 and five flat ground electrodes 1 are used as a group of discharge units. The discharge units are independently connected to a nanosecond pulse power supply 12, and the five rows of high-voltage line electrodes are connected to the nanosecond pulse power supply 12 as a series of current-limiting resistors 11. The resistance of the current-limiting resistor 11 is 5-10 kΩ. Each group of discharge units is independently Grounding wire, 5 flat ground electrodes 1 are connected as a group and then grounded. After the power supply form is optimized by adopting the partition excitation matching design, if a discharge unit has a partial breakdown, local adjustments can be made in time without affecting the overall operation of the equipment. Effect.

The shielding tube 2 is a 304 steel pipe with a notch on the upper part, and the wall thickness is not required; the high-voltage line electrode 5 adopts a steel wire above 304 as the line electrode, and the diameter of the steel wire is 1 mm, and the gap between the high-voltage line electrodes 5 in each column is 100 mm- 110 mm, the advantage of this setting is to increase the utilization of vertical space while maintaining the strength of the discharge area. The fastening bolt 8 adopts a round bolt, and the fastening nut 9 must be handled smoothly to prevent the generation of spark discharge at the tip.

The optimization of the power supply form refers to the use of nanosecond pulse power supply to excite the cooling tower defogging device. In addition, considering the normal operation of the cooling tower equipment and the equivalent load capacitance and electrode number of a single wire-plate electrode gap, the nanosecond The discharge capacitance of the pulse power supply is 400-600 pF; the pulse duration is 50-100 ns; the pulse voltage is adjustable from 0-60 kV, and the effective output is > 50 kV; the pulse repetition frequency is > 400 Hz, according to the cooling tower defogging equipment Working principle, the pulse type is determined as a negative pulse. Its working principle is as follows, that is, the negative voltage is output by the nanosecond pulse power supply, and the strong electric field generated by the high-voltage electrode ionizes the gas in the discharge area to generate corona discharge. Under the action of the electric field force, the ions and electrons collide and move, and adhere On the surface of the droplet, the droplet is charged, and the droplet moves to the direction of the plate electrode and is collected. The use of nanosecond pulse power supply excitation can effectively avoid the generation of spark discharge, and appropriately increase the intensity of corona discharge, thereby improving defogging Water saving efficiency.

The electrode structure of nanosecond pulse line plate discharge defogging is installed at the top of the cooling tower, and the nanosecond pulse power supply 12 is installed at the bottom of the cooling tower 10. The nanosecond pulse power supply 12 has its own control system, and the high voltage line electrodes of each discharge unit are respectively connected to A wire is connected to the current-limiting resistor on the electronic control platform and then connected to the nanosecond pulse power supply. The independent control of each discharge unit can be realized by setting parameters through the control system of the nanosecond pulse power supply.

The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and changes will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to better explain the principles and practical application of the invention, and to enable others of ordinary skill in the art to understand the invention and design various embodiments with various modifications as are suited to the particular use.

Claims (10)

1. A cooling tower for demisting based on nanosecond pulses, characterized in that: it includes plate electrodes and high voltage electrodes, the plate electrodes and high voltage electrodes are placed at intervals, and the high voltage electrodes are connected with nanosecond pulse power supply (12) for generating strong The electric field ionizes the gas in the discharge area to charge the droplets, and the plate electrode is grounded to collect the charged droplets. 2. A cooling tower for demisting based on nanosecond pulses according to claim 1, characterized in that: the plate electrode includes a flat ground electrode (1) and a shielding tube (2), and the shielding tube (2) is welded At the lower end of the flat ground electrode (1), an internal welding point (4) is provided at the bottom of the shielding tube (2), and a water flow groove (3) is formed between the lower part of the flat ground electrode (1) and the shielding tube (2). 3. A cooling tower for demisting based on nanosecond pulses according to claim 2, characterized in that: the top of the flat ground electrode (1) adopts an inverted ridge-shaped structure, and the included angle ranges from 40° to 90° °. 4. A cooling tower based on nanosecond pulse demisting according to claim 2, characterized in that: the shielding pipe (2) is a steel pipe with a gap on the upper part, and the lower part of the shielding pipe (2) is drilled with Outlet hole, shielding pipe (2) diameter range 25-58 mm. 5. The cooling tower for demisting based on nanosecond pulses according to claim 2, characterized in that: the shielding pipe (2) is installed obliquely, and the shielding pipe (2) is The inclination angle θ is 3-5 degrees. 6. A cooling tower for demisting based on nanosecond pulses according to claim 2, characterized in that: the high-voltage electrodes include high-voltage line electrodes (5) and high-voltage support frames (7), and the high-voltage line electrodes (5 ) and the high-voltage support frame (7) are fixed together by fastening screws (6), fastening bolts (8) and fastening nuts (9). 7. A cooling tower based on nanosecond pulse demisting according to claim 6, characterized in that: every three high-voltage line electrodes (5) are vertically arranged as a row, and five rows of high-voltage line electrodes (5) and Five flat ground electrodes (1) are used as a group of discharge units, and each column of high voltage line electrodes (5) in each group of discharge units is spaced from the flat ground electrodes (1). 8. A cooling tower based on nanosecond pulse defogging as claimed in claim 7, characterized in that: each group of discharge units is independently connected to a nanosecond pulse power supply (12), and 5 columns of high-voltage line electrodes are connected in series as a group The current limiting resistor (11) is connected to the nanosecond pulse power supply (12) afterward, and the resistance value of the current limiting resistor (11) is 5-10 kΩ. 9. The cooling tower for defogging based on nanosecond pulses according to claim 7, characterized in that: the gap in each column of the high-voltage line electrodes (5) is 100 mm-110 mm. 10. A cooling tower for defogging based on nanosecond pulses according to claim 7, characterized in that: each group of discharge units has a separate ground wire, and 5 flat ground electrodes (1) are grounded as a group.