CN105289847A - Static electricity high-efficient collecting device applicable to water mist discharged by wet cooling tower of thermal power plant - Google Patents

Abstract

The invention discloses an electrostatic high-efficiency trapping device for emptying water mist from a wet cooling tower in a thermal power plant. , Overhead device, grounding device. Water molecules are polar molecules, and the centers of gravity of the positive and negative charges do not coincide. The circulating cooling water of the cooling tower contains impurities and is a conductor. Due to the formation of a large number of free electrons and negative ions due to corona discharge, the water particles are charged. Under the action of the electric field, the free electrons move towards the positive hexagonal structure water mist collection stage (anode) under the action of the electric field force. When passing through the suspended water particles in the water mist, the free electrons will attach to the water particles to form negative ions, and Under the action of the electric field force, they gather on the anode, release electrons, and the suspended water particles settle into a liquid state. At the same time, due to the interaction between the particles after charging, the original small water particles will aggregate into larger particles. Under the action, it flows down the anode plate to realize efficient water recovery. The invention has the advantages of simple structure, low cost, corrosion resistance and long service life, can recycle and utilize cooling towers to empty water mist, and has broad engineering application prospects.

Description

An electrostatic high-efficiency trapping device for water mist exhaustion in wet cooling towers of thermal power plants

technical field

The invention relates to an electrostatic high-efficiency trapping device used for emptying water mist from a wet cooling tower of a thermal power plant, and belongs to the technical field of energy saving and emission reduction of thermal power plants.

Background technique

The water loss of wet cooling towers in thermal power plants includes three major parts: evaporation loss, wind blowing loss and sewage loss. Among them, evaporation loss and wind blowing loss are discharged into the air together with the air, resulting in a great waste of water resources. This is the largest water consumption in thermal power plants. one of the parts. Statistics show that the sum of water loss in wet cooling towers accounts for about 65%-75% of the total water loss in power plants. Taking 2×300MW thermal power units as an example, the evaporation loss is about 1130t/h, accounting for 62.08% of the water loss in power plants ; While the wet cooling tower improves the efficiency of the unit, it also increases the water consumption of the power plant sharply. Therefore, it is imperative to save water for the wet cooling tower of the thermal power plant.

Cooling tower evacuation Water mist is a gas-vapor mixture composed of air and water. From above the water distribution tank of the cooling tower to its outlet, what flows is a gas-liquid two-phase fluid—water mist and air. The particle size of the water form is generally below 100 microns, and the mechanical water eliminator basically has no effect on it, but it can With the help of electrostatic precipitation, water droplets condense and fall to recover water, which is a high-voltage electrostatic water recovery device.

But so far, the successful engineering application cases of cooling tower water mist recovery technology based on high-voltage electrostatic technology are rarely reported, and the existing water-saving technology still cannot fundamentally improve the problem of large water loss in wet cooling towers. Based on this, on the basis of predecessors' research, the present invention applies the principle of high-voltage electrostatic precipitation to develop a new set of high-voltage electrostatic recovery device for water mist, which is suitable for recovering and emptying water mist at the outlet of wet cooling towers in thermal power plants. The device has the advantages of simple structure, corrosion resistance, low manufacturing and operating costs, and long service life. It is expected to provide a feasible way to solve the efficient recovery of water mist from cooling towers in power plants, and has broad engineering application prospects.

Contents of the invention

The task of the present invention is to provide an electrostatic high-efficiency trapping device for evacuating water mist from a wet cooling tower in a thermal power plant, which is used to efficiently capture the evacuated water mist from a wet cooling tower in a thermal power plant.

An electrostatic high-efficiency trapping device for evacuating water mist from a wet cooling tower in a thermal power plant. , Overhead device, grounding device. In order to facilitate corona initiation and construct an extremely uneven electric field, the device of the present invention uses metal wires as corona electrodes and sets short tips (thorns) on the corona wires. The corona wire in the center of the tube is connected to the high-voltage DC cathode, and after electrification, a potential difference can be formed in the tube, that is, a high-voltage electrostatic field is formed around the corona metal wire. Each corona barbed metal wire corresponds to a conductive glass steel pipe with a regular hexagonal prism structure as a water mist collector, and the tube bundle is grounded. In order to prevent the corona wire from being directly connected to the pole plate through the water film on the bracket, surface discharge occurs, and the corona wire is overhead.

The beneficial results of the present invention are: the water mist recovery rate can reach more than 80%; taking the parameters of a 2×300MW unit as an example, it is calculated according to the current power plant water price of about 5 yuan/ton. According to the data obtained from the experiment, compared with not using this device, the average recovery rate is 80%, the cooling tower evaporation is 1130 t/h , and the recovered water is 904 t/h . The annual water saving is about 7919000 t , and the water cost is about 40 million yuan. The cost of this device is about 40 million yuan, excluding the operation and maintenance fee, the cost can be recovered within one year.

Description of drawings

Figure 1 is a schematic diagram of a cooling tower and a water removal device.

Fig. 2 is a perspective view of the overall structure of the present invention.

Fig. 3 is a schematic diagram of the arrangement of corona electrodes and water collection electrodes of a hexagonal prism unit in the electrostatic water removal device of Fig. 2 .

Fig. 4 is a top view of the electrostatic water removal device in Fig. 2 .

Fig. 5 is a schematic cross-sectional structure diagram taken along the line A-A in Fig. 4 .

Fig. 6 is a schematic diagram of the cross-sectional structure along the line B-B in Fig. 5 .

In the accompanying drawings, (1) is the fixing device of the electrostatic water removal component, (2) is the corona electrode (cathode), (3) is the water mist collector (anode) of the regular hexagonal prism structure, (4) is the cooling tower, ( 5) is an insulator, (6) is a controller, (7) is a high-voltage DC source, (8) is a grounding wire, (9) is a water collection tank, (10) is a fixed plate for the water collecting pole (anode), (11 ) is the fixing frame of the corona pole (cathode).

detailed description

Below in conjunction with accompanying drawing, specific embodiment of the present invention is described as follows:

When using the present invention, first install the above-mentioned electrostatic high-efficiency trapping device for the wet cooling tower of a thermal power plant to evacuate water mist on the upper end of the wet cooling tower of a thermal power plant, and use the electrostatic water removal component fixing device (1) to drain the water mist The electrostatic high-efficiency trapping device for air mist is fixed on the cooling tower. The corona electrode (cathode) (2) is connected to the cathode of the high-voltage direct current (7), and all water mist collectors (anodes) with regular hexagonal prism structures are connected to the ground wire (8). The high-voltage direct current (7) is connected with a controller (6), which can control the voltage.

When working, turn on the high-voltage direct current (7), and at the same time adjust the control voltage of the controller (6) so that it is at an appropriate and stable voltage value (corona initiation voltage). The corona electrode (cathode) (2) initiates a corona and creates an electric field around it. Due to the formation of a large number of free electrons and negative ions due to corona discharge, the water particles are charged. Under the action of the electric field, the free electrons move towards the positive hexagonal structure water mist collection stage (anode) under the action of the electric field force. When passing through the suspended water particles in the water mist, the free electrons will attach to the water particles to form negative ions, and Under the action of the electric field force, they gather on the anode, release electrons, and the suspended water particles settle into a liquid state. At the same time, due to the interaction between the particles after charging, the original small water particles will aggregate into larger particles. Under the action, it flows down the anode plate to realize efficient water recovery.

Claims (3)

1. An electrostatic high-efficiency trapping device for the wet cooling tower of a thermal power plant to evacuate water mist, characterized in that it consists of a high-voltage DC source (7), a controller (6), a corona electrode (cathode) (2), It is composed of a regular hexagonal prism structure water mist collector (anode) (3), an overhead device electrostatic water removal component fixing device (1), an insulator (5), and a grounding device (8). 2. An electrostatic high-efficiency trapping device for water mist evacuation of wet cooling towers in thermal power plants as described in claim 1, characterized in that: metal wires are used as corona poles (2) and are set on the corona wires The short tip is used to reduce the corona initiation voltage and facilitate the corona initiation; the corona wire is connected to the high-voltage DC cathode, and a high-voltage potential difference can be formed in the tube after electrification, that is, a high-voltage electrostatic field is formed around the corona metal wire. 3. An electrostatic high-efficiency trapping device for water mist evacuation of wet cooling towers in thermal power plants as described in claim 1, characterized in that: the water mist collector uses a conductive glass steel pipe (3) with a regular hexagonal prism structure, A corona barbed metal wire is installed in the center of each conductive glass steel pipe, the tube bundle is grounded, and the corona wire is overhead.