Development of NOx Removal Method Using a Permeable Roadside Fence Filled with Activated Carbon Fiber : Experimental

Transcription

1 5th IAPPA WORLD CLEAN AIR CONGRESS Development of x Removal Method sing a Permeable Roadside Fence Filled with Activated Carbon Fiber : Experimental Investigation of x Removal Performance *Takao Kanzaki ), Yoichi Ichikawa ), Toshihiro Kitada 3), Takaaki Shimohara 4), and Masaaki Yoshikawa 5) ) Daido niversity, Nagoya,Japan ) Ryukoku niversity,otsu,japan 3) Toyohashi niversity of Technology, Toyohashi, Japan 4) Fukuoka Institute of Health and Environmental Sciences, Dazaifu, Japan 5)Osaka Gas Co.Ltd.,Osaka,Japan

2 Today s talk.background and objective.experiments Wind tunnel Fence model Experimental conditions 3.Results x concentration ti profiles x removal rates 4.Conclusions

3 Background To reduce x concentration in urban areas x removal at roadside Verification test site in Osaka (8~)

4 Background To reduce x concentration in urban areas x removal at roadside ACF (Activated Carbon Fiber) is capable to remove, et al. x Permeable fence filled with ACF In operation : No additional air supply systems In maintenance : x removal performance is restored by flushing with water.

5 Permeable ACF fence Verification test on the site (Fukuoka, Osaka, Nagoya) Wind direction and velocity instantaneously vary. Evaluation of x removal rate is difficult. Wind tunnel experiments Homogeneous wind flow is easily reproduced. x removal rate Objective is to conduct wind tunnel experiments simulating a roadside gas diffusion process around the ACF fence and to investigate the x removal performance under homogeneous wind conditions.

6 Permeable ACF fence Panel-type permeable ACF fence Verification unit Fibrous ACF is homogeneously filled inside of fence Fence model (Scale :5) Slit-type permeable ACF fence Verification unit Inside of fence Felt-like ACF is attached into thin slits Miniature verification unit

7 Wind tunnel of CRIEPI * Settling and Contraction Sections Circuit Duct Test Section # Wind and Temperature Control nit Fan Circuit Duct 5m 5.5m Temperature Control nit Test Section # Turntable 4m Size of test section# : 3m 3. W 7m.7 H 7 m L CRIEPI * :Central Research Institute of Electric Power Industry

8 Flow geometry around ACF fence Windward fence Leeward fence. m. m.5 m H=. m x= m Experimental parameters Experiments Real unit Scale :5 - Fence height. m 5.5 m Road width.4 m m Wind velocity =.,3. m/s - ACF type Coal-tar-pitch-based fibrous ACF - ACF thickness L=.,.4 m.5,. m ACF filling rate ε=.5-3 g/cm 3 - Gas emission C H 4 : pure, 67 ml/s : 5 ppm, 7 ml/s : 5 ppm, 7 ml/s - Panel-type ACF fence model Size:. m W. m H -4mm t

9 Experimental conditions Experimental cases and parameters Fence configuration Case Velocity Fence configuration Thickness Single-fence case Leeward fence. m.55 m x=.9.6 H=. m [m/s] Windward Leeward L[mm] A 3 - B - C 3-4 D - 4 E 3 F G 3 4 H 4 Double-fence case Windward fence Leeward fence. m. m.5 m Experimental setup (case E) Leeward fence H=. m Wind Windward fence x=.9.6

10 .5 Concentration profiles and x removal rate for case A Case A (=3m/s, L=mm).5 CH4 CH4 Ru: Rd: R*:.5.5 Ru: Rd: R*: Windward Leeward. 5 Height 高さ z/ /Hf z/h f 5 5 高さ z/h f. 5 5 高さ z/h f. 5 5 高さ z/h f. 5 R* C/Q C/Q C/Q Removal rate R Removal rate R Leeward fence Hf : Fence height C/Q: Normalized concentration x removal rate ) Windward removal rate: Ru=[-(Cx,u / CCH4,u)] ) Leeward removal rate : Rd =[-(Cx,d / CCH4, d) ] 3) Overall removal rate : R* =[-(Cx,d / Cx,u ) ] i-species Ci,u:the windward concentration of Ci,d:the leeward concentration of i-species Ru Rd

11 .5 Concentration profiles and x removal rate for case Case A (=3m/s,L=mm) A CH4.5 CH4.5 Ru: Rd: R*: Windward Leeward.5 Ru: Rd: R*:. 5 Height 高さ z/ /Hf z/h f 5 5 高さ z/h f. 5 5 高さ z/h f. 5 5 高さ z/h f. 5 Leeward fence C/Q C/Q Removal rate R Removal rate R Case A Flow passes through inside of the ACF fence. and are removed using the ACF fence.

12 t z/h z/hf f 高さ z Height.5.5 Effects of wind velocity for single-fence case Case B (=m/s, L=mm) CH4 z/h f.5.5 CH4 /Hf.5.5 Ru: Rd: R*: Windward Leeward 高さ z 高さ z/ /Hf 高さ z/.5.5 Ru: Rd: R*: Leeward fence ht z/hf さ z/h f 高さ Heig Case A (=3m/s, L=mm) CH4.5 CH4.5 Ru:.5 5 C/Q C/Q Removal rate R Removal rate R 高さ z/h f.5 高さ z/h f.5 Rd: R*: 高さ z/h f.5 Ru: Windward Leeward Rd: R*: Leeward fence C/Q C/Q Removal rate R Removal rate R

13 z/hf Hf 高さ z/h Height.5.5 Effects of fence configuration Case E (Double-fence, =3m/s,.5.5 CH4 L=mm) CH4 Ru: Rd: R*:.5 Ru: Rd: R*: Windward Leeward Windward fence Leeward fence ht z/hf さ z/h f 高さ Heig Case A (Single-fence, =3m/s,.5.5 CH4 CH4 L=mm) Ru:.5 5 C/Q C/Q Removal rate R Removal rate R 高さ z/h f.5 高さ z/h f.5 Rd: R*: 高さ z/h f.5 Ru: Windward Leeward Rd: R*: Leeward fence C/Q C/Q Removal rate R Removal rate R

14 Concentration profiles of CH4 for double-fence case 45 =3m/s : ACF L=mm 45 =m/s : ACF L= mm 4 Case E 4 4 Case F Height 高さ z[mm] z [m mm] He eight z [mm] 高さ z[mm] ラインソースからの距離 x[mm] Distance from line-source x [mm] =3m/s : ACF L= 4mm Case G ラインソースからの距離 x[mm] Distance from line-source x [mm] =m/s : ACF L= 4mm Case H Case Velocity Thickness [m/s] L[mm] E 3 F G 3 4 H ラインソースからの距離 x[mm] Distance from line-source x [mm] ラインソースからの距離 x[mm] Distance from line-source x [mm]

15 x removal rate Case Velocity Fence Thickness removal rate [%] removal rate [%] [m/s] config. L[mm] Ru Rd R* Ru Rd R* A 3 single B single C 3 single D single E 3 double F double 45 (8) (97) 6 (57) (96) G 3 double H double ) Windward removal rate: Ru=-(Cx,u / Leeward fence CCH4,u) ) Leeward removal rate : Rd =-(Cx,d / CCH4, d ) 3) Overall removal rate : R * =-(Cx,d / Cx,u ) Ru Rd Ci,u:the windward concentration of i-species Ci,d:the leeward concentration of i-species R*

16 Exp. configuration Experimental setup Exp. conditions Slit spacing : 8 mm Side 側面図 view Top view 平面図 ラインソース,. m. m x= x=.9 x=.4 z=. z=.5 z=. z=.5.5m ACF fence ACF thickness: 5 mm Gas emission Flow condition ACF (SY-H8) : 5 ppm, 7 ml/s : 5 ppm, 7 ml/s Wind velocity :.5,. m/s Boundary layer thickness :.6 m Wind profile : /7 Size:.5 m W.5 m H. m L =. [m/s] y=.5.m y= Measuring probe ACF fence unit 4 : 測定点

17 Concentration profiles and x removal rate (a) : =.m/s (b) : =.m/s ユニット風上位置 Windward Leeward ユニット風下位置 ユニット風上位置 Windward Leeward ユニット風下位置 Height 高さ z [ z[mm m m ] m] Height 高さ z [ m z[m m ] mm] 除去率 [ % ] C/Q Removal rate [%] (c) : =.5m/s ユニット風上位置 Windward Leeward ユニット風下位置 (d) : =.5m/s ユニット風上位置 除去率 [ % ] C/Q Removal rate [%] Windward Leeward ユニット風下位置 t z [ z[mm] ] 高さ Heigh ht z [ m z[mm] m ] Heigh 高さ N O 除去率 [ % ] C/Q Removal rate [%] N O 除去率 [ % ] C/Q Removal rate [%]

18 x removal rate for slit-type ACF fence Wind velocity x removal rate [%] [m/s].5 86~93 4~ ~ Field obs. * 96 7 * Field observation (8-9, Osaka) x removal rate : R * =-(Cx,L ( / Cx,w ) Ci,w:the windward concentration of i- species Ci,L:the leeward concentration of i-species

19 Panel-type ACF fence Conclusions () For the single-fence case, and were removed up to more than 46% on the windward side of the fence. () For the double-fence case, the windward removal rates of and were considerably higher than that of a single-fence case because of the effects of the circulating flow between the two fences. On the windward side of the ACF fence, and were removed up to more than 57% under the present experimental conditions. Slit-type ACF fence () were removed up to 94% and were removed up to 39% () Results of x removal rate were comparable to the observations.

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