Carbon capture and storage (CCS) is considered to be one of the strategically important carbon abatement technologies that can be used to effectively reduce the carbon emissions from fossil fuel power plants and other large scale industrial processes, which are the major stationary sources of greenhouse carbon emissions. Compared to other capture technologies, solid adsorbents looping technology (SALT) based post-combustion carbon capture, an alternative to the state-of-the-art energy intensive amine scrubbing process, is widely viewed as being the most viable technology that can be used as either as a retrofit to existing power plants or new build capacity. The potential success of SALT technology is largely determined by the development of novel CO2 adsorbents. Amine immobilized solid adsorbents are highlighted to be used in SALT technology due to their high CO2 selectivity (CO2/N2 >1000), suitable adsorption temperature and tolerance of moisture. Although they have so much advantages on carbon capture, the oxidation and degradation of solid amines are still a significant problem to be overcome. The degradation of the amine adsorbent can lead to a reduction in CO2 capture performance and selectivity, an increase in the process cost and corrosion problems. The aim of this project is to 1) develop new solid adsorbent materials with higher CO2 capture ability and superior adsorption-desorption lifetime performance; 2) to investigate effective measures to minimise or effectively prevent the thermal and oxidative degradation of the sorbent materials; 3) to explore approaches that can rejuvenate the degraded sorbents for re-use or convert them into other value-added products. Firstly, a series of PEI-the porous siliceous cellular foams (SCF) adsorbents have been developed and characterised. The results show a relationship between the textural properties of SCF and CO2 adsorption ability of adsorbents. A highly effective hydrothermal methodology was developed to produce extremely mesoporous silica materials with well-defined mesoporous structures and greatly increased pore volumes of up to 3.2 cm3/g. The PEI adsorbents prepared using SCF-3-120-24 (1.6 cm3/g) was found to have CO2 capture capacities of nearly 180.8 mg/g, which represents the highest adsorption capacity ever reported for supported PEI adsorbents. Secondly, lifetime performance testing and strategies to mitigate the thermal-oxidative degradation of PEI adsorbents and rejuvenation of the degraded PEI was investigated. The presence of moisture and additives was seen to enhance the thermal-oxidative stability of PEI. Furthermore, the doping of Na2B4O7 hydrates can increase the cyclic adsorption-desorption lifetime performance of PEI adsorbent. Meanwhile, the CO2 adsorption capacity of one heavily degraded PEI adsorbent was increased from 2.8 wt% to 6.2 wt% after rejuvenation test. Finally, hydrous pyrolysis and a continuous flow reactor system was used in catalytic hydrotreatments and hydrothermal treatments of six model MEA degradation compounds and two degraded MEA solvents. Most of the model compounds and degraded MEA was converted to piperazine derivatives in a H2 reaction atmosphere and pyrazine derivatives in NH3 reaction atmosphere. Piperazines and pyrazines are a type of important pharmaceutical intermediates.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:765479 |
| Date | January 2018 |
| Creators | Sun, Yuan |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/54251/ |
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