CN100531862C - Apparatus and method for removing grains with combined action of sound wave and additional seed grain - Google Patents

Abstract

The invention relates to a device used for removing absorbable granules PM2.5 based on acoustic wave and with the addition of associative action of seed granules and a method thereof, in particular to a set of devices used for removing the absorbable granules (hereinafter called PM2.5 for short) with grain diameter less than 2.5 micrometers in dusty gas and a method thereof. The device comprises a sound source, an acoustic agglomeration chamber, a feedway for the seed granules, subsequent normal dedusting equipment, etc. When flue gas discharged by various combustion sources or other dusty gas flows through the acoustic agglomeration chamber, fine granules in airflow arise entrainment of different degrees under the action of the acoustic wave, while the added seed granules nearly do not arise entrainment due to relatively large inertia thereof; meanwhile, the fine granules and the seed granules are different in gravity settling and acoustic drift. The three reasons lead to relative movement between the fine granules and the seed granules, thus generating quite high collision rate between the absorbable granules PM2.5 and the seed granules. After the absorbable granules PM2.5 collide with the seed granules, agglomeration happens between the absorbable granules PM2.5 collide with the seed granules; coacervate generated by the agglomeration is further removed by the subsequent normal dedusting equipment.

Description

The apparatus and method of sound wave and additional seed grain removing grains with combined action thing

Technical field

The present invention relates to a cover remove particle diameter in the dust-contained airflow less than 2.5 microns pellet (hereinafter to be referred as PM _2.5) apparatus and method, belong to the technical field that pollution control equipment is made.

Background technology:

In the current granular material discharged control technology, traditional method is the principles such as inertia, diffusion and electrostatic interaction according to particle, adopts routines such as electrostatic precipitator, cyclone separator, sack cleaner and ceramic filter to remove equipment and removes particle.Although the particle that these equipment remove greater than 5 μ m has reached very high efficient, to fine particle PM _2.5Removal efficiency lower, still have the fine particle of a myriad of to be disposed in the atmosphere, can not satisfy at present strict day by day environmental requirement.In general, adopt the approach that improves traditional dust collection method removal effect can run into actual difficulty, as adopting efficient cyclone separator, its resistance drop can increase greatly; In high-efficiency electrostatic dust remover, increase the electric field number, add long electrode and just can make originally that very big electric cleaner volume becomes huger, and power consumption also increases greatly.

Because general acoustic agglomeration method is being hanged down under the sound intensity PM _2.5Reunion efficient lower, only have about 40%.The present invention is based on the synergy of sound wave and additional seed grain,, adopt the bulky grain after follow-up conventional dust arrester will be reunited further to remove again, finally reach and efficiently remove PM as the preprocessing process that fine grained in the dust-contained airflow is carried out acoustic agglomeration _2.5Purpose.

Retrieve in existing patent, it is as follows to obtain relevant Chinese patent and document:

1, the patent No.: 02276809.2, vertical granule flow dust remover

2, the patent No.: 03132195.X, rotating fluidized bed blowback gravel bed filter

3, the patent No.: 200510095431, some cloth technique for dust removal combined and equipment thereof

4, the patent No.: 200510032204, flue type dust removal and purification apparatus

5, the patent No.: 01130066.3, coagulation type electrostatic dust removing method and device thereof

6, the patent No.: 96105749.1, the type of bleeding dust collection method and dust arrester

7, the patent No.: 92102104.6, high efficiency dust remover by magnetization adsorption

8, the patent No.: 99106814.9, a kind of ultrasonic concussion dust collection method and device

In the patent of the above-mentioned relevant particulate removal that retrieves, all can not remove effectively and can suck particle PM _2.5Wherein the 8th patent is to adopt the dedusting of ultrasonic concussion method, because the supersonic dust removal effect under the lower-wattage is relatively poor, energy consumption is bigger when adopting the ultrasonic wave of higher-wattage, so be difficult to guarantee reliably working steady in a long-term.This devices and methods therefor adopts sound wave and seed grain synergy method under reliable and stable low-frequency sound source, remove particle size range effectively and be the ultra-fine grain that the conventional cleaner of 0.01～2.5 μ m is difficult to capture.

Summary of the invention

Technical problem: the objective of the invention is to adopt a kind of sound wave and additional seed grain synergy to remove PM _2.5Apparatus and method, to the pellet PM in smoke evacuation, diesel engine vent gas and other dust-contained airflow of coal-burning power plant _2.5Remove, reach control PM _2.5The purpose of discharging.The present invention utilizes sound source, by sound wave and the symphyogenetic preprocessing process of additional seed grain, in conjunction with follow-up dust arrester, can remove the PM in the dust-contained airflow efficiently _2.5

Technical scheme: sound wave of the present invention and additional seed grain synergy remove PM _2.5Device in, an end of the horizontal flue of dust-contained airflow import is connected with the upper end of vertical acoustic agglomeration chamber; The seed grain feeder is connected with the top with vertical acoustic agglomeration chamber; Two sides at middle part, vertical acoustic agglomeration chamber are connected with horizontally disposed two reducing tube connectors by adpting flange respectively, and the other end of two reducing tube connectors is connected with two sound sources with flange respectively; The lower part outlet end of vertical acoustic agglomeration chamber is connected with particle first order separator, and the outlet of first order separator is connected with second level separator again, and the port of export of second level separator is connected with air-introduced machine through flue; Air-flow after will being handled by air-introduced machine is at last discharged.

Sound wave of the present invention and additional seed grain synergy remove PM _2.5Device remove PM _2.5Method be:

1) determining of sound source operating frequency: after the operating frequency of sound source is determined, calculate wavelength at this operating frequency lower plane sound wave, make that by the length that changes the reducing tube connector spacing between two sound sources is the half-wavelength integral multiple, when two sound sources are installed on the position of integral multiple of half-wavelength, in the acoustic agglomeration chamber, form standing wave;

2) determining of vertical acoustic agglomeration chamber total height: the total length of vertical acoustic agglomeration chamber is the difference in height that dust-contained airflow passes in and out vertical acoustic agglomeration chamber, according to the gas flow of handling, determine the cross section and the total length of acoustic agglomeration chamber, guarantee that dust-contained airflow is not less than 3 seconds in indoor total time of staying of acoustic agglomeration;

3) adding of seed grain: additional seed grain is added by the seed grain feeder by the top of vertical acoustic agglomeration chamber, seed grain is solid particle or liquid particles, select the size of particle according to the frequency of sound wave, the seed grain that adds relies on the gravity of self, imports air-flow and enters vertical acoustic agglomeration chamber;

4) start sound source, open the particle feeder at top, vertical acoustic agglomeration chamber simultaneously, seed grain is added in the vertical acoustic agglomeration chamber with specified feeding coal.Pending dust-contained airflow, enter vertical acoustic agglomeration reunion chamber by passage after, the PM in the air-flow _2.5What be subjected to sound wave simultaneously carries and adds oarse-grained capture effect secretly, and the dust-contained airflow after processed enters first order separator and second level separator separator again, and last air-introduced machine is discharged.

Symphyogenetic theoretical foundation and computational process

(1) sound wave is carried the relative motion that causes secretly

Because the effect of stickiness makes particle vibrate with the vibration of gas molecule, it is the distinctive character of granule that sound wave is carried secretly to granule in acoustic wavefield.Fine grained carrying secretly in acoustic wavefield is expressed from the next

$\mathrm{\η}=\frac{1}{\sqrt{1+{\left(\mathrm{\ω\τC}\right)}^2}}---\left(1\right)$

Its physical significance is the ratio of particle vibration amplitude and air particle vibration amplitude.ω in the formula 1 is an angular frequency, ω=2 π f, and f is a frequency; τ is the relaxation time of particle, and expression formula is

$\mathrm{\&tau;}=\frac{{\mathrm{\&rho;}}_{\mathrm{<figure-callout\; id="2"\; label="d\; d\; p"\; filenames="C200710132690E00081.png"\; state="\{\{state\}\}">d</figure-callout>}}{d_p}^{}{{}_{}}^2}{18\mathrm{\&mu;}}---\left(2\right)$

ρ in the formula 2 _pIt is grain density; d _pIt is particle radius; μ _gIt is the gas medium dynamic viscosity.C is the Ken Ninghan correction factor, and its definition is

$C=1+\frac{2{\mathrm{\&lambda;}}_g}{d_p}(1.257+0.400e^{-0.55d_p/{\mathrm{\&lambda;}}_g})---\left(3\right)$

λ in the formula 3 _gIt is the air molecule mean free path.

According to formula 1, for the particle that varies in size, it is carried coefficient secretly and there are differences.Shown the bigger relative velocity of generation between granule of fully carrying secretly and the seed grain of being carried secretly hardly, reunited for the particle collision and created condition.For seed grain among the present invention captures PM _2.5Theoretical foundation is provided.

(2) relative motion that causes of gravitational settling

According to particle sinking speed in air

$U_G=\frac{{\mathrm{\&rho;}}_p{{\mathrm{gd}}_p}^{2}C}{18\mathrm{\&mu;}}---\left(4\right)$

Wherein g is an acceleration of gravity.The big or small particle sinking speed different with density is by difference.In the vertical acoustic agglomeration chamber of this patent, there is different particle sinking speeds in the seed grain that yardstick is bigger with fine grained, and produces relative velocity.Gravitational settling also is one of foundation that increases collision rate between particle.

(3) sound causes the relative motion that drift causes

The asymmetric particle that causes of the stickiness of particle in sound wave is carried secretly drifts about in standing-wave sound field, and the sound of particle causes drift velocity by following expression

$U_{\mathrm{drift}}=\frac{1}{24\mathrm{\&mu;}}{{\mathrm{<figure-callout\; id="2"\; label="kd\; p"\; filenames="C200710132690E00081.png"\; state="\{\{state\}\}">kd</figure-callout>}}_p}^2\mathrm{\&eta;}{U}_0\sin \left(2\mathrm{kx}\right)---\left(5\right)$

Wherein k is a wave number, U ₀Be the SVEL amplitude, x is position in the acoustic wavefield.From formula 5 as can be known, bigger seed grain and can suck particle PM _2.5Between different drift velocities is arranged in sound field, and make and produce relative velocity between particle.

Beneficial effect: under reliable sound source and additional seed grain synergy,, remove several peak concentration particle diameters PM in the dust-contained airflow in sub-micron regions effectively in conjunction with follow-up cleaner _2.5It is important feature of the present invention.By test, device of the present invention can make fine grained PM in the dust-contained airflow _2.5Several concentration removal efficiencies reach 68%, the removal efficiency of mass concentration reaches 80%.This device is applicable to the occasion that environmental protection and air cleaning have higher requirements.

Description of drawings

Fig. 1 is a general structure schematic diagram of the present invention.Wherein have: flue 1, vertical acoustic agglomeration chamber 2, sound source 3, seed grain feeder 4, first order separator 5, second level separator 6, air-introduced machine 7.

The specific embodiment

Whole device of the present invention is divided into three parts as shown in Figure 1: sound source; Dust-contained airflow channel system (reunion chamber); Add particle system and follow-up conventional cleaner.Follow-up conventional cleaner among this figure as an example, adopts the two-stage expansion chamber to separate, and has corresponding cutting particle diameter.Can adopt single-stage or multistage all kinds of conventional cleaner during actual the use.

Concrete connected mode is as follows: an end of the horizontal channel of dust-contained airflow import is connected with the upper end of vertical acoustic agglomeration chamber; The vibrating material feeding device that adds particle is connected with the top with vertical acoustic agglomeration chamber; Two sides at middle part, acoustic agglomeration chamber are installed adpting flange respectively, are connected with horizontally disposed two reducing tube connectors; The other end of two reduced pipes is connected with two sound sources with flange; The port of export of acoustic agglomeration chamber (lower port) is connected with the particle separation chamber, for guaranteeing that separating effect can contact to connect multistage conventional separator is set; The downstream of separator is connected with air-introduced machine through flue by flange; Air-flow after will being handled by air-introduced machine is at last discharged.

The operating frequency of sound source calculates the wavelength at this operating frequency lower plane sound wave after determining, makes that by the length that changes reduced pipe the spacing between two loudspeaker is the half-wavelength integral multiple.When two sound sources are installed on the position of integral multiple of half-wavelength, in the acoustic agglomeration chamber, form standing wave.

Determining of vertical acoustic agglomeration chamber total height: the total length of acoustic agglomeration chamber is the difference in height that dust-contained airflow passes in and out vertical acoustic agglomeration chamber.According to the gas flow of handling, determine the cross section and the total length of acoustic agglomeration chamber, guarantee that dust-contained airflow is not less than 3 seconds in indoor total time of staying of acoustic agglomeration.

Additional seed grain is added by the top of acoustic agglomeration chamber.Seed grain can be solid particle or liquid particles, selects the size of particle according to the frequency of sound wave, and when being 1kHz as frequency of sound wave, the seed grain size is 15～20 μ m, and corresponding seed grain concentration magnitude is 10 ⁴Individual/cm ³.The seed grain that adds relies on the gravity of self, imports air-flow and enters the acoustic agglomeration chamber.

The bulky grain that should guarantee to remove after the reunion to choosing of separation equipment can all be separated from air-flow, and the cut diameter of separation equipment is chosen for D ₅₀Be no more than the diameter of seed grain,, can adopt multi-stage separation in order to guarantee the later separation effect.

The concrete running of this apparatus system is as follows: start sound source, open the charging gear at top, acoustic agglomeration chamber simultaneously, with specified feeding coal seed grain is added in the acoustic agglomeration chamber.Pending dust-contained airflow, enter vertical acoustic agglomeration reunion chamber by passage after, the PM in the air-flow _2.5What be subjected to sound wave simultaneously carries and adds oarse-grained capture effect secretly, and the dust-contained airflow after processed enters conventional separation equipment (for example first and second grades of conventional separators among Fig. 1) again, and last air-introduced machine is discharged.

Claims (2)

1. the device of sound wave and additional seed grain removing grains with combined action thing is characterized in that an end of the horizontal flue (1) of dust-contained airflow import is connected with the upper end of vertical acoustic agglomeration chamber (2); Seed grain feeder (4) is connected with the top with vertical acoustic agglomeration chamber (2); Two sides at middle part, vertical acoustic agglomeration chamber (2) are connected with horizontally disposed two reducing tube connectors (22) by adpting flange (21) respectively, and the other end of two reducing tube connectors (22) uses flange to be connected with two sound sources (3) respectively; The lower part outlet end of vertical acoustic agglomeration chamber (2) is connected with particle first order separator (5), and the outlet of first order separator (5) is connected with second level separator (6) again, and the port of export of second level separator (6) is connected with air-introduced machine (7) through flue; Air-flow after will being handled by air-introduced machine is at last discharged.

2. the method that removes the microparticle thing of the device of sound wave as claimed in claim 1 and additional seed grain removing grains with combined action thing is characterized in that this method is:

1) determining of sound source (3) operating frequency: after the operating frequency of sound source is determined, calculate wavelength at this operating frequency lower plane sound wave, make that by the length that changes reducing tube connector (22) spacing between two sound sources (3) is the half-wavelength integral multiple, when two sound sources (3) are installed on the position of integral multiple of half-wavelength, in the acoustic agglomeration chamber, form standing wave;

2) determining of vertical acoustic agglomeration chamber (2) total height: the total length of vertical acoustic agglomeration chamber (2) is the difference in height that dust-contained airflow passes in and out vertical acoustic agglomeration chamber, according to the gas flow of handling, determine the cross section and the total length of acoustic agglomeration chamber, guarantee that dust-contained airflow is not less than 3 seconds in indoor total time of staying of acoustic agglomeration;

3) adding of seed grain: additional seed grain is added by seed grain feeder (4) by the top of vertical acoustic agglomeration chamber (2), seed grain is solid particle or liquid particles, select the size of particle according to the frequency of sound wave, the seed grain that adds relies on the gravity of self, imports air-flow and enters vertical acoustic agglomeration chamber;

4) start sound source (3), open the particle feeder (4) at top, vertical acoustic agglomeration chamber (2) simultaneously, with specified feeding coal seed grain is added in the vertical acoustic agglomeration chamber (2), pending dust-contained airflow, after entering vertical acoustic agglomeration chamber by passage, microparticle thing in the air-flow is subjected to carrying secretly of sound wave simultaneously and adds oarse-grained capture effect, and the dust-contained airflow after processed enters first order separator (5) again to be separated with second level separator (6), and last air-introduced machine is discharged.

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