This study was aimed at the removal of odorous compounds in gases emitted from rubber processing industries. Odorous gas for test was prepared by mixing fresh air and an odorous gas drawn from an oven in which a sample of rubber powder was kept at 160 and 200 oC, respectively. For ozonation tests, the prepared odorous gas was then premixed with a definite amount of ozone-enriched air before entering into a contact system. The contact system consists of two sieve-plate columns connected in series and each column has four 1-L chambers. Depending on with or without introducing a circulating scrubbing water into the columns, the oxidation reaction could be either wet or dry one. For UV/ozonation (UV/O3) tests, batch reactions were performed in a 3.63-L chamber fitted with an UV lamp inserted in a quartz column. A definite volume of the odorous gas generated from the oven was injected into the chamber containing a definite concentration of ozone.
Results from the dry-ozonation tests indicate that that 82 and 70% of VOCs and odorous intensity in the influent gas could be removed, respectively, with the operation conditions of an initial ozone concentration of 4.0 ppm, VOC (methane equivalent) concentrations of 6.5-9.0 ppm, an oxidation temperature of 38.5 oC, and a gas empty-bed-retention time (EBRT) of 8.6 s. Both the VOC and odorous intensity removal efficiencies were roughly proportional to the EBRT in the range of 1.4-11.4 s. Wet-ozonation got 97 and over 90% of VOC and odorous intensity removal, respectively, with the operation conditions of initial ozone concentration 4.0 ppm, VOC (methane equivalent) concentrations 6.5-10.3 ppm, oxidation temperature 37.3 oC, gas EBRT 12 s, and liquid/gas rate ratio 0.01 m3/m3. With conditions similar to those cited above, odor concentration (dilutions to the threshold) in the test gas could be removed from 3,090 to 130 with an EBRT of 14.5 s. Tests also indicate that activated carbon is effective for both physical and chemical removals of the residual VOCs, odorous compounds, and ozone in the effluent gas from the ozonation system. Economical analysis indicates that around NT$ 5.4 is required for treating 1,000 m3 of the tested foul gas by the proposed wet-ozonation and activated carbon adsorption process. Odor concentration (dilutions to the threshold) in a test could be reduced from around 4,000 to 70.
Results of UV/O3 tests indicate that the introduction of the 185 nm UV irradiation at the intensity of 5W/3.63L did not help in the additional VOC and odor removals with an initial ozone concentration 4.0 ppm, VOC (methane equivalent) concentrations of 12.2-15.0 ppm, oxidation temperature of 31.5 oC, and reaction time 18.2 s. UV irradiation is not necessary for the ozonation odor removal of the test gas samples.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0701108-160115 |
| Date | 01 July 2008 |
| Creators | Cheng, Li-Yi |
| Contributors | Chung-Shin Yuan, Wen-Jhy Lee, Ming-Shean Chou |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0701108-160115 |
| Rights | withheld, Copyright information available at source archive |
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