The Research Progress of Coagulation Technology on Fine Particles

This article reviewed some of the measures taken to control particulate matters by combining the latest fine particles dominating technologies both at home and abroad. The coagulation technological principles and research achievements of fine particles were suggested. The research highlightly analyzed the technical principles and characteristics of electric coagulation technology, acoustic coagulation technology, vapor condensation technology, thermal coagulation technology,chemical coagulation technology, magnetic coagulation technology, turbulent coagulation technology and light coagulation technology.On the basis of comprehensive analysis of these technologies, it pointed out the development trend of fine particle control technology.

Acoustic Coagulation of Fine Particles from WFGD

The objective of this study is employing acoustic coagulation to induce agglomeration of fine and ultrafine particles after wet flue gas desulfurization (WFGD) and analyzing its effectiveness and characteristic based on numerical simulation. Matters such as calcium sulfate and calcium sulfite in WFGD can form very fine particles. Smoluchoski’s equation is employed as the simulating model. Orthokinetic coagulation, hydrodynamic coagulation and Brownian coagulation are taken into account to form the agglomeration kernel. An improved sectional arithmetic is introduced to achieve sectional size adjusting automatically according to the mass concentration of particles, so that section size is fine where the mass concentration is large to guarantee computational accuracy, but coarse where the mass concentration is small to save computation time. Besides, mass conservation rate is introduced to estimate the calculation error in the compute of mass concentration. Simulation results show that the overall number concentration decreased more than 40% after acoustic wave acting on the flue gas for 2 second; Increasing sound intensity level (SIL) is more effective to coagulation than increasing frequency; There exists an optimal acoustic wave frequency within 1500~2000Hz; Coarse particles are more sensitive to acoustic wave frequency than fine particles.

RESEARCH INTO THE INFLUENCE OF THE ACOUSTIC FIELD ON THE EFFICIENCY OF REMOVING AEROSOLS / AKUSTINIO LAUKO ĮTAKOS AEROZOLIO ŠALINIMO EFEKTYVUMUI TYRIMAS

The paper presents the methods for reducing harmful aerosols from galvanic baths polluting the environment under conditions when air flow helps in forming an acoustic field above the bath. The findings show that the level of air humidy is the lowest when aerosols are removed with the help of a side exhauster. Side effects on acoustic coagulation may occur. Aerosol coagulates when elevated above the liquid and returns to liquid not dispersed in the evironment. The article introduces active suckers in accordance to their form and effectiveness collecting pollutants. The dependence of humidity on temperature is analyzed under the impact of external factors such as sucking, blowing and sucking or blowing, sucking and an acoustic field. The paper also discusses data on the dependence of sound pressure and looks at the level of frequency distribution. Santrauka Atliktas kenksmingų garų (aerozolio), patenkančių į aplinką nuo galvaninių vonių, tyrimas, kai jiems šalinti naudojamas aktyvintasis šoninis siurbtuvas su oro srautu, kuris suformuoja akustinį lauką virš vonios. Parodyta, kad oro drėgnumas kinta nereikšmingai esant skysčio temperatūroms iki 85 ºC, kai kartu su siurbimu naudojami aeroakustiniai srautai, dėl kurių pasireiškia akustinė koaguliacija. Nustatyta, kad aerozoliui pakilus virš skysčio, vyksta koaguliacija, ir jis, nepasklidęs į aplinką, sugrįžta į skystį. Aptariami aktyvintieji šoniniai siurbtuvai pagal formą ir efektyvumą surenkant teršalus. Analizuojama drėgnumo priklausomybė nuo skysčio temperatūros, veikiant išoriniams veiksniams: siurbimui; siurbimui ir pūtimui; siurbimui, pūtimui ir akustiniam laukui. Atlikta sukuriamo akustinio lauko parametrų analizė: garso slėgio intensyvumo ir garso slėgio lygio pasiskirstymas dažnio srityje.

ACOUSTIC METHOD OF AIRPORT FOG PRECIPITATION

The influence of an acoustic field on the dispersed phase of a fluid has been studied in connection with the application of acoustic coagulation for the precipitation of gases. An acoustic field, depending on the intensity and frequency of the wave, as well as the physical condition of the medium, may cause coagulation, i.e. the joining of small particles into larger aggregates. This paper gives an example of the applications of dispersed phase acoustics, with particular emphasis on recent developments, e.g. the acoustic method of airport fog precipitation. This innovative technology is based on the fact that water can be collected from fog under the influence of acoustic waves. This work presents the new results of the analysis of the action of the acoustic field on the fog.