Abstract
This study armed to develop a chemical scrubbing process to treat an emitted odorous gas stream from a corn-germ oil-pressing machine.
Analytical results demonstrated that the gas contains a total VOC (volatile organic compound) concentration of 323 to 2,100 ppm calibrated as methane. Major VOC ingredients are aldehydes, organic acids, and mercaptans. Ozone, sodium hypochlorite (NaOCl), and hydrogen peroxide (H2O2) were used as oxidants for VOCs other than aldehydes and sodium bisulfite (NaHSO3) was used as a reductant for aldehydes.
Experimental setup used in this study consisted of a set of four-stage-in-series scrubbers for VOC oxidation and a set of 18-L bubble column for aldehyde reduction. Each stage of the scrubber was constructed from a 25-cm x 140-cm (OD x H) plastic column packed with 2¡¨-diameter plastic packings to a height of 90 cm.
Experiment results showed that suitable conditions for the VOC and odor removal in the oxidation tower are: (1) QL/QG (flowrate ratio of circulating liquid and gas) = 0.0024-0.0035 m3 liquid/m3 gas, (2) dose rate of NaOCl solution (10 % effective chlorine) = 0.0125-0.015 L/m3 gas, (3) pH of the circulating liquid = 7.5-8.0, and (4) supplemental water flowrate = 2.4-5.0 L/m3 gas. Those for the reduction of the residual aldehydes and other odorous compounds are: (1) concentration of NaHSO3 scrubbering solution = 2,156 mg/L as SO2 and (2) pH of the NaHSO3 solution = 5.0-6.0.
Under the conditions, experimental data demonstrated that the process could reduce H2S from 0-5.5 to 0 ppm, NH3 from 0.1-0.4 to 0-0.1 ppm, phenols from 0-2.0 to 0 ppm, acids from 15-25 to 0 ppm, acetaldehyde from 10-34 to 0-10 ppm, amines from 0.1 to 0.1 ppm, and mercaptans from 0.5-10.5 ppm to 0 ppm. Overall VOC removal efficacy was 85-100 %. Effluent gas from the oxidation stage had a chlorine smell, while that from the reduction one was odorless.
Based on the results from the pilot study, a full-scale plant with a waste gas flow rate 105 m3/min was proposed. It was estimated that the full-scale plant has an equipment cost of US$ 45,000, and an operating cost of around US$ 110/(8-hr day) or US$ 0.75/(1,000 m3 waste gas).
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0715102-162558 |
| Date | 15 July 2002 |
| Creators | Huang, Li-Min |
| Contributors | none, none, 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-0715102-162558 |
| Rights | unrestricted, Copyright information available at source archive |
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