Rapid treatment of trace toluene in air with an air cleaner consisting of a continuous adsorption-and-desorption concentrator and photocatalytic reactor with a parallel array of nine light sources
Advancing the chemical engineering fundamentals
Chemical Reaction Engineering: Advanced Concepts (T2-2b)
Keywords: Air clearner, Photocatalytic reactor, Continuous adsorption and desorption cencentrator, toluene
Fumihide SHIRAISHI1*, Takaaki Ishimatsu1, Kenji TATEISHI2, Hiroyuki SHIMA2, and Hideyuki YAMAMOTO3
1 Department of Systems Design, Bio-Architecture Center, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan
2 I-Quark Corporation, 1-36-14, Matsushima,Higashi-ku, Fukuoka 812-0062, Japan
3 Ars Research System Co., Ltd., 8-33-3, Momochihama, Sawara-Ku, Fukuoka 814-0001, Japan
*Corresponding author
It is very difficult to certainly and rapidly treat trace volatile organic compounds (VOCs) in indoor air. This is due to the fact that a diffusional resistance caused by the film in the very vicinity of the photocatalyst surface remarkably decreases the rate of decomposition because of low VOC concentrations. In a previous work1), we developed an air cleaner consisting of a continuous adsorption-and-desorption concentrator and photocatalytic reactor and then examined treatment of the air containing trace formaldehyde. As a result, we found a high performance of this apparatus. The objectives of the present work are to miniaturize the air cleaner and evaluate its applicability to trace toluene in the air.
The fine zeolite particles-loading honeycomb rotor (diameter; 12 cm, thickness; 5 cm) was slowly rotated at 1/12 r.p.m. The air including trace toluene was continuously supplied to the 3/4 sectional area of the rotor at 0.27 m3/min to adsorb the toluene. On the other hand, the air circulated at 0.09 m3/min in a loop was heated instantaneously and supplied to the 1/4 surface area of the rotor to desorb toluene. The toluene desorbed was supplied to the small box with a volume of 0.0156 m3 in the loop and then decomposed in the photocatalytic reactor with a parallel array of nine 6W blacklight blue fluorescent lamps (the details of the structure are available elswhere2, 3)). By rotation of the electric fan at the upper part of the reactor, contaminated air was sucked from the bottom of the reactor and allowed to rise through the inside of each glass tube. The linear velocity of air was large enough (>11 m/s) to treat the air under the condition of negligible film-diffusional resistance. The air cleaner was set up in a closed room of 1 m3 and toluene was artificially generated in a range of 1-3 ppm.
When only the concentrator was operated, the toluene concentration in the room decreased to the neighborhood of zero concentration in 10 min and then became constant, while that in the small box instantaneously increased and then became constant. When both the concentrator and reactor were operated, on the other hand, the toluene concentration in the room decreased more rapidly to a zero concentration, while that in the small box instantaneously increased, then decreasing and becoming zero. The experimental result clearly shows that the miniaturized apparatus also has a high performance. The photocatalytic activity and the ability of the rotor to adsorb toluene were very stable.
References
1) F. Shiraishi, S. Yamaguchi, and Y. Ohbuchi, Chem. Eng. Sci., 58, pp.929-934 (2003).
2) F. Shiraishi, D. Ohkubo, K. Toyoda, and S. Yamaguchi, Chem. Eng. J., 114, pp.153-159 (2005).
3) F. Shiraishi, K. Toyoda, and H. Miyakawa, Chem. Eng. J., 114, pp.145-151 (2005).
See the full pdf manuscript of the abstract.
Presented Monday 17, 15:40 to 16:00, in session Chemical Reaction Engineering: Advanced Concepts (T2-2b).
