Title: Clean Electricity Generation from Sewage: a novel Ultra-Supercritical Water Oxidation Technology with integrated CCS
Abstract: Waste management and clean electricity generation are amongst the most critical challenges and major barriers towards achieving sustainability. Ultra-Supercritical water oxidation (USWO) is an emerging technology that can possibly provide a solution for mitigating both these issues. It inherently allows the use of low-grade fuels, such as waste, for electricity generation with high efficiency. However, the true potential of USWO technology has not been extensively reported in the existing literature. This study focuses on modelling and optimisation of a novel USWO process working on the principles of Brayton cycle for electricity generation using sewage as fuel. The USWO process is integrated with carbon capture and storage (CCS) technology to reduce CO2 emissions. The process design also incorporates water recovery facility from the sewage used as the fuel stream. An advanced system level process model is developed in Aspen Plus simulator using experimentally derived inputs together with FORTRAN programs. A sensitivity analysis is conducted to determine the impact of reactor temperature on the net electrical efficiency. The results indicate that the USWO technology can generate electricity from sewage with net electrical efficiency of 31.5%,. It is also observed that integration of CCS can reduce the CO2 emissions to zero with an efficiency penalty of 3.5% points. This efficiency penalty is comparable to the best performing CCS technologies for conventional gas- and coal-fired power plants. The sensitivity results show the electricity output is proportionate to reactor temperature and is primarily restricted by the material properties of the USWO reactor. The results also indicate nearly complete recovery of water from the sewage without any additional processing or energy requirement. Furthermore, the study also provides a systematic methodology to test other low-grade fuels (organic wastes) for the proposed USWO technology.
Publication Year: 2021
Publication Date: 2021-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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