報告書番号

V08059

タイトル（和文）

高活性炭素繊維を充填した通風式フェンスによる沿道大気浄化手法の開発 －NOx除去性能の実験的解明－

タイトル（英文）

Deveropment of NOx purification method using a permeable roadside fence filled with activated carbon fiber -Experimental investigation of NOx removal performance-

概要 （図表や脚注は「報告書全文」に掲載しております）

高活性炭素繊維（ACF, Activated Carbon Fiber）は優れた窒素酸化物（NOx）浄化性能を有し、通風式フェンスに充填して沿道に設置すれば、都市域のNOx除去に有効な手法となる。本研究では、ACFを充填した通風式フェンスを設計する上で重要となる、一定風速条件下でのNOx除去性能を明らかにするために、沿道拡散場を模擬した風洞実験を行った。パネル型通風式フェンスを道路片側に設置した場合、実験条件の範囲内では、NO2除去率はフェンス風上側で33～46％、風下側でほぼ100％であり、NO除去率はフェンス風上側で6～35％、風下側で17～33％であった。また、パネル型通風式フェンスを道路両側に設置した場合、フェンス風上側ではNO2除去率は44～57％、NO除去率は14～25％であった。なお、パネル型通風式フェンスではフェンス表層付近を通過する気流とACFの接触によりNOｘが除去されるため、性能評価には局所的なNOx除去率を調べることが重要である。スリット型通風式フェンスのNOx除去性能は実験条件の範囲内では、NO2除去率は82～92％、NO除去率は24～61％であり、実証試験結果よりも高い値であった。また、NO除去率は気流風速が低いほど増加することが明らかになった。これはNO除去にはACFとの接触時間を増加させることが有効であることを示唆している。

概要 （英文）

Activated Carbon Fiber (ACF) is capable of purifying NOx. Therefore, it is very effective for reduction of the ambient NO2 concentration in urban areas to set up a permeable fence filled with ACF near arterial roads; hereafter, this fence is called the ACF fence. In this work, to develop the NOx purification method using the ACF fence, we conducted a wind tunnel experiment simulating a roadside gas diffusion process around the ACF fence and investigated the NOx removal performance of the ACF fence under homogeneous wind condition. Concentration of NO2 and NO were measured just before and after the ACF fence. To quantitatively evaluate the NOx removal performance of the ACF fence, the NOx removal rate were estimated on the basis of concentration statistics. Experiments were conducted for two types of ACF fence, that is, a panel-shaped fence and a slit-shaped fence. In case where the panel-shaped fence was installed on the leeward side of the road, the windward removal rate of NO2 was 33 to 46 %, the leeward removal rate of NO2 was around 100 %, the windward removal rate of NO was 6 to 35 %, and the leeward removal rate of NO was 17 to 33 %. In case where the panel-shaped fence was installed on both sides of the road, the windward removal rates of NO2 and NO were 44 to 57 % and 14 to 25 %, respectively. In case where the slit-shaped fence was installed on the leeward side of the road, the overall removal rates of NO2 and NO were 82 to 92 % and 24 to 61 %, where these were higher than observation values on the verification test site. The overall removal rates of NO increased for lower wind velocity case. This suggests that increasing contact efficiency between polluted air and ACF surface layer is effective for NO removal.

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