CN105910999B - It is a kind of to measure devices and methods therefor of the charged single drop to fine particle adsorbance - Google Patents

Abstract

The invention belongs to the field of particle adsorption measurement, and relates to a device and method for measuring the adsorption amount of charged single droplets to fine particles, comprising a sequentially connected micro air pump, a particle generation chamber and an adsorption chamber; the particle generation chamber is provided with a hatch cover And the metal mesh, the metal mesh is connected with the first high-voltage electrostatic generator; the upper end of the adsorption chamber is provided with a droplet generating device, and the lower end is provided with a through hole, and the adsorption chamber is connected with the monitoring device; the charged droplet generating device includes an insulating sleeve and a metal A flat capillary; the metal capillary is connected to the injection pump, and the body of the metal flat capillary is connected to the second high-voltage electrostatic generator. The invention has a simple structure and a reasonable design, and can accurately measure the adsorption amount of a charged single droplet to fine particles, thereby studying the mechanism of electrostatic spray dust removal; it is helpful to the design and research of electrostatic spray dust removal systems, improves the efficiency of electrostatic spray dust removal, and effectively controls smoke. Air and other fine particulate matter emissions.

Description

A device and method for measuring the adsorption capacity of charged single droplet on fine particles

technical field

The invention belongs to the research field of particle adsorption measurement, in particular to a device and method for measuring the adsorption of charged single droplets to fine particles.

Background technique

Atmospheric fine particle pollution has posed a serious threat to human health. Relevant data show that 80% of the world's population is above the World Health Organization's air quality guidelines, resulting in about 3.2 million deaths per year related to atmospheric fine particle pollution. As an emerging industrial manufacturing country, the problem of fine particulate matter pollution in the atmosphere is particularly prominent in China. In 2013, 92% of the 74 cities included in the national PM2.5 monitoring scope did not meet the standards, of which 32 cities had PM2.5 concentrations more than twice the national standard, and the top ten cities more than three times higher. It is imminent to strengthen the control of fine particulate matter.

Atmospheric fine particles mainly come from coal-fired power plants, motor vehicle exhaust and construction site dust, etc. Controlling the emission of fine particles from the source is one of the important measures to control the pollution of atmospheric fine particles. In the prior art, the use of electrostatic spray dedusting technology to remove fine particles in the gas is an effective means of fine particle emission control, especially for nano-scale particles, the removal efficiency can exceed 90%.

In the electrostatic spray dust removal system, fine particles are affected by Coulomb force, etc., and are deposited on the surface and inside of the charged droplets to complete the capture process. The capture efficiency is affected by the charge amount, relative velocity and physical parameters of droplets and fine particles, and there will be large fluctuations. The adsorption of fine particles by charged single droplets is the basis for studying the dust removal process of electrostatic spraying. Accurate measurement of the adsorption capacity of charged single droplets on fine particles is helpful for in-depth research on electrostatic spray dust removal technology, design and optimization of electrostatic spray dust removal systems, improvement of dust removal efficiency of electrostatic spray dust collectors, and effective control of fine particle emissions.

Contents of the invention

The object of the present invention is to provide a device and method for measuring the adsorption capacity of charged single droplets to fine particles in response to the above problems. set mechanism.

The technical solution of the present invention is: a device for measuring the adsorption capacity of charged single droplets to fine particles, including a micro air pump, a first high-voltage electrostatic generator, a particle generating chamber, an adsorption chamber, a metal flat capillary, a syringe pump, a second High-voltage electrostatic generator, monitoring device and camera device;

The micro air pump is connected to the particle generation chamber through an insulating tube; the particle generation chamber is provided with a metal mesh, and the metal mesh is electrically connected to the first high-voltage electrostatic generator; the particle generation chamber and the adsorption chamber are connected through a first hard Insulation pipe connection;

One end of the metal flat capillary extends into the top of the adsorption chamber, and the other end is connected to the syringe pump through a second hard insulating tube; the tube body of the metal flat capillary is electrically connected to the second high-voltage electrostatic generator; the bottom of the adsorption chamber A through hole is opened, and the through hole is on the same axis as the metal flat-mouthed capillary; a shooting area is provided under the adsorption chamber, and filter paper is placed horizontally at the position directly facing the through hole under the shooting area; the camera device is installed at a position facing the shooting area ; The camera device is electrically connected to the computer;

The monitoring device includes a particle concentration monitoring device, a humidity monitoring device and a current monitoring device, and the probes of the particle concentration monitoring device, the humidity monitoring device and the current monitoring device extend into the adsorption chamber respectively.

In the above solution, the gap of the metal mesh 5 is not greater than 0.5mm.

In the above solution, the particle generating chamber 6 is provided with a hatch 1 .

In the above scheme, the center of the top of the adsorption chamber 8 is provided with an insulating sleeve 9 for fixing the metal flat capillary 10, and one end of the metal flat capillary 10 extends into the top of the adsorption chamber 8 through the insulating sleeve 9, and is connected with the insulating sleeve. Barrel 9 is squeezed and connected.

In the above solution, the bottom of the adsorption chamber 8 is fixedly connected with a bracket 14 .

In the above solution, the diameter of the through hole 15 is 20 to 30 times the diameter of the metal flat capillary 10 .

In the above solution, the particle concentration monitoring device is a particle concentration monitor.

In the above solution, the humidity monitoring device is a hygrometer.

In the above solution, the current monitoring device is an ammeter.

A method of measuring the device for measuring the adsorption capacity of charged single droplets on fine particles according to the rights, comprising the following steps:

S1. Pre-configure different concentrations of fine particles and water mixtures. After mixing evenly, use a dropper to sequentially collect sample droplets on filter paper and dry them. The particle concentration gray scale of different gray scales is made by image processing technology on the computer. color chart;

S2. Open the hatch cover of the particle generating chamber to add an appropriate amount of fine particles, then close the hatch cover and turn on the micro air pump; open the first high-voltage electrostatic generator and adjust it to a preset value; the first high-voltage electrostatic generator provides charge for the metal mesh, and the After the airflow output by the micro air pump is mixed with the fine particles in the particle generating chamber, it is charged, rectified and filtered by the metal mesh, and enters the adsorption chamber through the first hard insulating tube;

S3. When the particle concentration monitoring device of the monitoring device connected to the adsorption chamber shows that the particle concentration reaches the preset value and is stable, turn off the micro air pump, turn on the syringe pump, turn on the second high-voltage electrostatic generator and adjust it to the preset value, and then the adsorption Lay filter paper under the through hole at the lower end of the chamber, and turn on the camera device of the high-speed digital image capture system to shoot in the preset shooting area for image acquisition;

S4. By changing the working conditions, multiple sets of droplet adsorption fine particle data are obtained, including photographed images and corresponding filter paper samples; the filter paper containing droplets under different working conditions is treated the same as the filter paper in step S1 and compared to produce Form the second color comparison card of particle concentration grayscale; carry out gray scale processing on the photographed image and correlate with the second color comparison card to make the third color comparison card of particle adsorption amount; carry out the third color comparison card of particle adsorption amount gray scale The relationship between the particle adsorption amount and the gray scale of the collected image is obtained by calculating the gray scale difference;

S5. When measuring the adsorption amount of charged droplets to fine particles again, the grayscale of the droplet image collected by the camera device can be substituted into the relationship between the amount of particle adsorption and the grayscale of the collected image in step S4 to calculate the adsorption of charged droplets to fine particles. the amount of adsorption.

The beneficial effects of the present invention are: compared with the prior art, the device of the present invention is simple in structure and reasonable in design, and can accurately measure the adsorption amount of charged single liquid droplets on fine particles, thereby studying the adsorption mechanism of electrostatic spray dust removal; The design and research of the electrostatic spray dust removal system improves the dust removal efficiency of the electrostatic spray dust collector and effectively controls the emission of fine particles in flue gas and other gases. Through the associated calibration of steps S4 and S5, the method of the present invention can effectively reduce the measurement error caused by the direct optical measurement caused by the deposition and uneven deposition of fine particles on the surface of the droplet.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

In the figure: 1. Hatch cover; 2. Insulating pipe; 3. Micro air pump; 4. The first high-voltage electrostatic generator; 5. Metal mesh; 6. Particle generating chamber; 7. Hard insulating pipe; 8. Adsorption chamber; 9. Insulating sleeve; 10. Metal flat capillary; 11. Injection pump; 12. Second high-voltage electrostatic generator; 13. Monitoring device; 14. Bracket; 15. Through hole; 16. Filter paper; 17. Shooting area; 18 , The second hard insulating tube.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals represent the same or similar parts. The accompanying drawings are only used to illustrate the present invention, and do not represent the actual structure and true scale of the present invention.

Figure 1 shows an embodiment of the device for measuring the adsorption capacity of charged single droplets to fine particles according to the present invention. The device for measuring the adsorption capacity of charged single droplets to fine particles includes a micro air pump 3 connected in sequence, The particle generation chamber 6, the adsorption chamber 8, the first high-voltage electrostatic generator 4, the metal flat capillary 10, the syringe pump 11, the second high-voltage electrostatic generator 12, the monitoring device 13 and the camera device.

The micro-air pump 3 is connected to the particle generating chamber 6 through an insulating tube 2; the particle generating chamber 6 is provided with a particle feeding hatch 1 for adding fine particles, which acts as a seal when closed. The middle part of the particle generation chamber 6 is equipped with a metal mesh 5 parallel to its bottom surface, the metal mesh 5 is electrically connected to the first high-voltage electrostatic generator 4, and the gap of the metal mesh 5 is not greater than 0.5mm, which can prevent the mixed air flow of fine particles. Charge, rectify and filter. The particle generation chamber 6 is connected to the adsorption chamber 8 through the first rigid insulating tube 7, which enhances the air flow stability and reduces the adhesion and agglomeration of fine particles on the tube wall; the upper end of the adsorption chamber 8 is a droplet generating device, and the The droplet generating device comprises an insulating sleeve 9 and a metal flat capillary 10; Stretch in the top of the adsorption chamber 8 through the insulating sleeve 9, the metal flat capillary 10 is squeezed and connected with the insulating sleeve 9, and is detachable, which is convenient for changing the metal flat capillary 10 of different calibers; the other end of the metal flat capillary 10 passes through the second The hard insulating tube 18 is connected with the syringe pump 11 to reduce the influence of the pressure fluctuation in the tube on the drop size; the tube body of the metal flat capillary tube 10 is electrically connected with the second high-voltage electrostatic generator 12 . The bottom of the adsorption chamber 8 has a through hole 15. The through hole 15 is on the same axis as the metal flat capillary 10. The diameter of the through hole 15 is 20 to 30 times the diameter of the metal flat capillary 10. At the same time, the leakage of particle mixture gas is reduced. The bottom of the adsorption chamber 8 is fixedly connected with a bracket 14, and the bracket 14 supports the adsorption chamber 8. There is ample space below the adsorption chamber 8, that is, a shooting area 17, which can be used for high-speed camera equipment to collect images. Place the filter paper 16 horizontally at the position facing the through hole 15 below the shooting area 17; the camera is installed at a position facing the shooting area 17; the camera is electrically connected to the computer; the particle generation chamber 6 and the adsorption chamber 8 are all made of insulating materials and ground. The polarities of the first high voltage electrostatic generator 4 and the second high voltage generator 12 are opposite.

The monitoring device 13 includes a particle concentration monitoring device, a humidity monitoring device and a current monitoring device, the probes of the particle concentration monitoring device, humidity monitoring device and current monitoring device protrude into the adsorption chamber 8 respectively. Wherein, the particle concentration monitoring device is a particle concentration monitor, the humidity monitoring device is a hygrometer, and the current monitoring device is an ammeter.

A method for measuring the device for measuring the adsorption capacity of charged single droplets to fine particles, comprising the following steps:

S1. Pre-configure different concentrations of fine particles and water mixtures. After mixing evenly, use a dropper to sequentially collect sample droplets on filter paper and dry them. The particle concentration gray scale of different gray scales is made by image processing technology on the computer. color chart;

S2, open the hatch cover 1 of the particle generating chamber, add an appropriate amount of fine particles, then close the hatch cover 1 and turn on the micro air pump 3; open the first high-voltage electrostatic generator 4 and adjust it to a preset value; the first high-voltage electrostatic generator 4 feeds the metal mesh 5 Provide charging, the airflow output by the micro air pump 3 is mixed with the fine particles in the particle generating chamber 6, charged, rectified and filtered through the metal mesh 5, and enters the adsorption chamber 8 through the first rigid insulating tube 7;

S3. When the particle concentration monitoring device of the monitoring device 13 connected to the adsorption chamber 8 shows that the particle concentration reaches a preset value and is stable, the micro air pump 3 is turned off, the syringe pump 11 is turned on, and the second high-voltage electrostatic generator 12 is turned on and adjusted to a preset value. Set the value, lay the filter paper 16 below the through hole 15 at the lower end of the adsorption chamber 8, and open the camera device of the high-speed digital image capture system to shoot in the preset shooting area 17 for image acquisition;

S4. By changing the working conditions: including the output voltage of the first high-voltage electrostatic generator 4, the second high-voltage electrostatic generator 12, and the flow rate of the syringe pump 11, etc., multiple sets of droplet adsorption fine particle data, including captured images and corresponding filter papers, are obtained Sample; the filter paper 16 containing liquid droplets under different working conditions is treated the same as the filter paper in step S1 and compared to make the second color comparison card of particle concentration grayscale; the captured image is grayscale processed and compared with the second Corresponding to the color card, the third color card of the particle adsorption amount is made; the gray scale difference calculation is performed on the third gray scale color card of the particle adsorption amount to obtain the relationship between the particle adsorption amount and the gray scale of the collected image;

S5. When measuring the adsorption amount of charged droplets to fine particles again, the grayscale of the droplet image collected by the camera device can be substituted into the relationship between the amount of particle adsorption and the grayscale of the collected image in step S4 to calculate the adsorption of charged droplets to fine particles. the amount of adsorption.

Due to the small momentum of the fine particles, most of them will be deposited on the surface of the droplet after reaching the charged droplet, and some hydrophilic fine particles will enter the droplet and gather on its inner surface. The difficulty in accurately measuring the adsorption of charged droplets to fine particles by optical means lies in the accurate calibration of the optically collected images. The deposition characteristics of fine particles lead to large errors in direct optical calibration, so it is not suitable to use a calibration method similar to optical measurement of solution concentration. The present invention adopts the standard mixed solution-sampled mixed solution-sampled image correlation calibration method involved in steps S1 to S4, which can greatly improve the accuracy of measuring the adsorption amount of charged droplets to fine particles by means of optical measurement.

It should be understood that although this description is described according to various embodiments, not each embodiment only includes an independent technical solution, and this description of the description is only for clarity, and those skilled in the art should take the description as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions for feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiment or All changes should be included within the protection scope of the present invention.

Claims (10)

1. a kind of measuring device of the charged single drop to fine particle adsorbance, which is characterized in that including micro air pump (3), the Room (6), adsorption chamber (8), metal flat mouth capillary (10), syringe pump (11), the occur for one HV generator (4), particle Two HV generators (12), monitoring device (13) and photographic device；

The micro air pump (3) occurs room (6) with particle and is connect by insulation tube (2)；The particle occurs to be equipped with gold in room (6) Belong to net (5), the metal mesh (5) is electrically connected with the first HV generator (4)；Room (6) and adsorption chamber occur for the particle (8) it is connected by the first rigid insulation pipe (7)；

The top of adsorption chamber (8) is stretched into one end of the metal flat mouth capillary (10), and the other end passes through the second rigid insulation pipe (18) it is connect with syringe pump (11)；The pipe shaft of metal flat mouth capillary (10) is electrically connected with the second HV generator (12)； Hole (15) is opened in the bottom of the adsorption chamber (8), and the through-hole (15) is in same axis with metal flat mouth capillary (10)；Institute The lower section for stating adsorption chamber (8) is equipped with shooting area (17), and the position of shooting area (17) lower section face through-hole (15) is horizontal positioned Filter paper (16)；Photographic device is mounted on the position for facing shooting area (17)；Photographic device and calculating mechatronics；

The monitoring device (13) includes granule density monitoring device, humidity detection device and current monitoring device, the particle The probe of concentration monitoring device, humidity detection device and current monitoring device is respectively protruding into the adsorption chamber (8).

2. according to claim 1 measure device of the charged single drop to fine particle adsorbance, which is characterized in that described Metal mesh (5) gap is not more than 0.5mm.

3. according to claim 1 measure device of the charged single drop to fine particle adsorbance, which is characterized in that described Particle occurs room (6) and is equipped with hatchcover (1).

4. according to claim 1 measure device of the charged single drop to fine particle adsorbance, which is characterized in that described Adsorption chamber (8) top center is equipped with the insulating sleeve (9) for fixing metal flat mouth capillary (10), the metal flat mouth capillary The one end for managing (10) is stretched at the top of adsorption chamber (8) by insulating sleeve (9) and is press-connected with insulating sleeve (9).

5. according to claim 1 measure device of the charged single drop to fine particle adsorbance, which is characterized in that described The bottom of adsorption chamber (8) is fixedly connected with holder (14).

6. according to claim 1 measure device of the charged single drop to fine particle adsorbance, which is characterized in that described Through-hole (15) aperture is 20~30 times of metal flat mouth capillary (10) caliber.

7. according to claim 1 measure device of the charged single drop to fine particle adsorbance, which is characterized in that described Granule density monitoring device is granule density monitor.

8. according to claim 1 measure device of the charged single drop to fine particle adsorbance, which is characterized in that described Humidity detection device is hygronom.

9. according to claim 1 measure device of the charged single drop to fine particle adsorbance, which is characterized in that described Current monitoring device is ammeter.

10. a kind of measuring charged single drop to the measurement method of fine particle adsorbance device, spy according to claim 1 Sign is, includes the following steps：

S1, it is pre-configured with various concentration fine particle and water mixed liquid, is existed after mixing with dropper successively collecting sample drop It on filter paper and dries, the first colorimetric card of granule density grayscale of different grayscale is made up of image processing techniques；

S2, opening particle occur the appropriate fine particle of room hatchcover (1) addition and are then shut off hatchcover (1) opening micro air pump (3)；It beats It opens the first HV generator (4) and is adjusted to preset value；First HV generator (4) provides lotus to metal mesh (5) Electricity, after the fine particle in air-flow and particle generation room (6) that the micro air pump (3) exports mixes, by metal mesh (5) lotus Electricity, rectification and filtering enter adsorption chamber (8) by the first rigid insulation pipe (7)；

The granule density monitoring device for the monitoring device (13) that S3, the adsorption chamber (8) connect shows that granule density reaches default Micro air pump (3) is closed when being worth and stablizing, opens the syringe pump (11), and the second HV generator of opening (12) is adjusted to pre- If value lays filter paper (16) below adsorption chamber (8) lower end through-hole (15), and opens the camera shooting of high-speed digital image capture system machine Device is shot in default shooting area (17), carries out Image Acquisition；

S4, by changing operating mode, obtain multigroup drop absorption fine particle data, including shooting image and corresponding filter paper sample This；Filter paper (16) containing drop under different operating modes is carried out and the filter paper same treatment of step S1 and is compared, is made Grain concentration the second colorimetric card of grayscale；Shooting image is carried out gray proces and corresponding with the association of the second colorimetric card granular absorption is made Three colorimetric card of flow control；Grey scale difference calculating acquisition granular absorption amount is carried out to granular absorption amount grayscale third colorimetric card with acquisition to scheme As gray-scale relation formula；

S5, again measure charged droplet to fine particle adsorbance when can by photographic device acquire Liquid particle image gray scale substitute into step Adsorbance of the charged droplet to fine particle is calculated with acquisition gradation of image relational expression in granular absorption amount in rapid S4.