Loading of Agglomerate Particles on Flat Filter Media

Transcription

1 Loading o Agglomerate Particles on Flat Filter Media Qisheng Ou 1*, David Y. H. Pui 2 and Da-Ren Chen 1** 1 Washington University in St. Louis, St. Louis, MO Particle Technology Laboratory, University o Minnesota, Minneaolis, MN * Current address: University o Minnesota, Minneaolis, MN ** Current address: Virginia Commonwealth University, Richmond, VA Particle Technology Laboratory

2 Outline Introduction & Review Objectives Exerimental Method Exerimental Results Semi-emirical Model Summary and Conclusions 2

3 Nanoarticle Agglomerates Containing rom a ew u to thousands o Primary Particles Ubiquitous Large surace area Al 2 O 3 rom synthetic ume (Okuyama et al, 1986) Soot article rom diusion lame (Sorensen, 2011) Increasing health concern Mild steel welding ume (Kalliomaki et al, 1987) Carbonaceous agglomerate rom urban aerosol (Katrinak et al, 1993) 3

4 Previous Study on Agglomerate Particle Filtration (Kim et al., 2009b) (Ou et al., 2012) Surace iltration (Fu et al., 1990) Pressure Dro [in H 2 O] (Lange et al., 1999) Deth iltration Transition regime 4 (Kim et al., 2009a) Initial iltration Mass Loaded er Area [g/m 2 ]

5 Objectives To erorm the exerimental study to investigate the behavior (i.e., evolution o ressure dro and enetration) o lat ilter media loaded with agglomerate articles, esecially in both deth and transition iltration regimes. To develo semi-emirical models to describe/redict the ilter loading behavior observed in the exeriments. 5

6 Agglomerate Particle Generation Diusion Flame Burner N 2 Air Air Methane Generation (Kim et al., 2009b) Precursor Characterization Particle Material Precursor Formula Vaor ressure Boiling oint SiO 2 Tetraethyl orthosilicate <1 20 ºC ºC Fe 2 O 3 Iron entacarbonyl ºC 103 ºC 6

7 Agglomerate Particles Generated SiO 2 Branch-like, D 1.8 Primary article size: 15 nm to 80 nm. 18.3±5.9 nm 48.9±18.0 nm 83.4±21.1 nm Fe 2 O 3 Chain-like, D 1.0 Primary article size: 40 nm to 130 nm. 44.0±17.9 nm 71.6±26.2 nm 88.4±30.3 nm 7

8 Filtration Exeriment Overview and Setu Initial Filtration Penetration (Mono) Deth & Transition Filtration Pressure Dro (Poly) Penetration (Mono) Polydiserse Testing Monodiserse (DMA-classiied) Testing 8

9 Filtration Exeriment Tested Filter Media Thickness Basic Weight Solidity Permeability DOP Media [mm] [g/m 2 ] [--] [m 2 ] [%] Fiberglass A E Fiberglass B E Fiberglass C E Cellulose E Fiberglass A Fiberglass B Fiberglass C Cellulose 9

10 10 Initial Filtration Initial Penetration o Sherical and Agglomerate Particles

11 Deth & Transition Filtration Pressure Dro Evolution (Loading Curve) 11 Media Eective Pore Diameter [µm] V u [cm 3 /m 2 ] KCl SiO 2 Fe 2 O 3 Cellulose Fiberglass A Fiberglass B ~ 0 Fiberglass C ~ 0 ~ 0

12 12 Deth & Transition Filtration Penetration Evolution

13 Deth & Transition Filtration Deosition Proiles & Dendrite Structures SiO 2 agglomerates Fe 2 O 3 agglomerates Fixing the dendrite structure by condensing cyanoacrylate vaor onto tested ilter media and traed articles. Laminar Flowmeter Filter Holder Diusion Dryer Comressed Air Dro o cyanoacrylate adhesive Water Bath ( 80 C) Bubbler Vaor Tra 13

14 Deth & Transition Filtration Thomas Model Bergman et al. (1978) P = 16πµ U t L + L + ( α L = 64µ U L + L (( α L α Z( d Thomas et al. (2001) ) 0.5 ) ) α α + )( d d L L α + d 2 ) 0.5 Fiber resistance Dendrite resistance F µ Z α α L L d d : Drag coeicient : Gas dynamic viscosity : Filter thickness : Packing density o ilter : Volume raction o deosited articles : Length o ibers by area : Length o dendrite by area : Filter iber diameter : Particle diameter Bergman s Model underestimates the ressure dro due to homogeneous deosition assumtion. 14 Thomas Model slices a ilter into multile layers along thickness, and aly Bergman s model to each layer.

15 Deth & Transition Filtration Modiication o Thomas Model Perormance o Thomas Model Modeling Penetration: Thomas Model (inherited rom Bergman s model): Proosed Model: mm JJ,tt = 1 αα JJ,tt 1 1 αα EE JJ,ii,ttmm JJ,tt uu JJ,ii,tt nn cc nn cc ii=1 mm JJ,tt = αα JJ,tt 1 1 αα EE JJ,ii,ttmm JJ,tt uu JJ,ii,tt ii=1 15 EE JJ,ii,tt = 1 1 EE JJ,ii,tt 1 EE JJ,ii,tt nn cc mm JJ,tt = EE JJ,ii,tt mm JJ,tt uu JJ,ii,tt ii=1 nn cc mm JJ,tt = EE JJ,ii,tt mm JJ,tt uu JJ,ii,tt ii=1

16 Deth & Transition Filtration Comarison between Model and Exeriment Pressure Dro Evolution 16

17 Deth & Transition Filtration Comarison between Model and Exeriment Penetration Evolution 17

18 Summary The deth and transition iltration behaviors o agglomerate articles on lat ilter media were exerimentally studied. Branch-like and chain-like agglomerates were generated by a diusion lame burner, and their loading on three iberglass and one cellulose ilter media were studied. For certain ilter media, agglomerate articles clog ilter media much aster than sherical articles with similar overall mobility size distribution. For high eiciency media (iberglass C), the deth iltration regime was not observed rom the characteristics o loading curve or agglomerate articles. A semi-emirical model based on the revision o existed Thomas model was roosed. Reasonably good agreement was ound between exerimental result and model rediction regarding to the loading-evolution o both ilter ressure dro and enetration. Providing the imrovement in the rediction o enetration evolution 18 The article holding caacity limit o ilter media needs to be obtained via exerimental data.

19 Loading o Agglomerate Particles on Flat Filter Media Thanks or your attention. Questions? qou@umn.edu