The present work deals with capture and storage of carbon dioxide from biogases by bond- ing to alkaline earth metals from power plant ashes. The aim is to achieve the feed-in standard in Germany for the natural gas grid by binding CO2 in a long-term stable and environmentally compatible manner. In addition, the ash quality is to be improved by reduced mobility of critical metals such as lead, zinc and cadmium, and calcium carbonate is to be recovered as a valuable material in addition to the biomethane.
In several experimental setups from laboratory scale to pilot plant, it was shown that both carbon dioxide and hydrogen sulfide can be captured and stored in large quantities of ash residues. Both the use of a packed column to compensate for the poor absorption and reaction kinetics and the use of ammonium chloride as an extraction agent proved to be particularly effective for biogas upgrading to biomethane level. In contrast, both the absorption and reaction temperature, as well as gas-specific influencing factors such as carbon dioxide concentration and volume flow rate, had little to no influence.
With regard to ash quality, an improvement of the landfill class from IV to 0 was achieved with respect to lead, from II to 0 for zinc and from III to I for cadmium. A significant improvement was also achieved for chlorine, but this did not result in a reduction of the landfill class. The ash quantity could be reduced by more than 50 %, among other things, by dissolving out the alkaline earth metals for the carbon dioxide reaction.
As further research steps, it remains to further reduce the metal mobility with respect to the ash eluate in order to better optimize the process water quality. This could be achieved, for example, by a controlled pH value.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:88753 |
| Date | 22 December 2023 |
| Creators | Sakowski, Bastian Alexander |
| Contributors | Mollekopf, Norbert, Möst, Dominik t, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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