Carbon dioxide sequestration using brines has emerged as a promising technology to mitigate the adverse impacts of climate change due to its large storage capacity and favourable chemistries. However, the permanent storage (mineral trapping) of CO2 in brines takes significantly long periods of time as the formation of carbonates is very slow. The main parameters (brine pH, system temperature and pressure, brine composition) have been reported to have the major effect on mineral trapping of CO2 sequestration in brines. It is suggested that the precipitation of mineral carbonates is mostly dependent on brine pH and is favoured above a basic pH of 9.0. In order to promote the formation of carbonates, brine pH could be enhanced by using additives. Synthetic brines were used in this study instead of natural brines due to the difficulty in obtaining and storing fresh natural brines. Therefore, the suitability of using synthetic brines as analogues of natural brines for CO2 sequestration studies was evaluated firstly. The experimental studies were then conducted to assess a series of additives (host rock, buffer solutions and fly ash) and select the optimal additives that could maximise the precipitation of mineral carbonates and quantify the storage capacity of CO2 via mineral trapping with additives. Finally, the geochemical modelling studies were conducted (by the code PHREEQC V2) to assess the solubility trapping of CO2 in brines with additives, and compared with the corresponding experimental results.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:581991 |
| Date | January 2012 |
| Creators | Liu, Qi |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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