| Author: | Guan, Jianyu |
| Title: | Stripping of biogas and formation of elemental sulfur by sulfide oxidation |
| Advisors: | Leu, Shao-yuan (CEE) |
| Degree: | M.Sc. |
| Year: | 2018 |
| Subject: | Hong Kong Polytechnic University -- Dissertations Water -- Purification Sewage -- Purification Water reuse |
| Department: | Faculty of Construction and Environment |
| Pages: | v, 55 pages : color illustrations |
| Language: | English |
| Abstract: | This thesis aims to develop a lab-scale system and the related mathematical model for harvesting H2S from biogas and converting it to elemental sulfur. Biogas is the main product of anaerobic digestion (AD) of biodegradable waste and sewage sludge. It mainly composes of methane (Concentration over 50%) and therefore is a great source of bioenergy. H2S removal is mandatory in the energy recovery process for protecting the instrument and co-generator. Hong Kong's sea-water toilet flushing system is one of the most unique features for water supply in the world, however it also creates various challenge in terms of wastewater treatment, i.e., the high H2S in the sewer after the anaerobic process. It was discovered from our preliminary tests that the H2S content in the biogas generated from the anaerobic digester can be as high as 20,000 ppm, which is 67 times higher than that from flash water system. Therefore, the goal of this study is to investigate a low-cost strategy to remove and recover the sulfur content in the wastewater through micro-aeration. The stripping process using the absorbent to inhale the Hydrogen sulfide and keep it stored by oxidation to achieve the goal of removing H2S and harvesting element sulfur. Although this issue is widely discussed, most focus on the effects of different types of adsorbents are mainly concerned, and just a few studies have been conducted on the process of dynamic absorption and element sulfur harvesting. The micro-aeration stripping simulation system in laboratory is used to clarify the relationship of dynamic chemical equilibrium and chemical kinetics. Gas transfer experiments have been carried out based on the fixed pH (10, 11, 12), and the absorption rate of H2S exceeds 99.3%. Without maintaining the pH value, only the initial pH value is adjusted to 9.92 and 10.77. In the simulation process, the change of pH could reflect the change of absorption rate by the stripping test of CO2. the relationship between pH and absorption rate is established, and we can figure out the dynamic chemical equilibrium and Chemical kinetics relationship in the micro-aeration system (the system's KLa02 is about 2.7 (h-)). Adjusting the initial concentration of carbonated in. the Absorbent (0 mol/L, 6.3 × 10-4 mol/L, 0.01 mol/L) comparing model data together with practical data, rationality and validity of the model are verified. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991022244146203411.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 1.66 MB | Adobe PDF | View/Open |
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