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Abstract: A significant proportion of the research into CCS in the literature assumes ‘complete capture’ of the CO2, that is at least 85 to 90 percent of the CO2 from the flue gas is captured for the entire operating year (7,000 to 8,000 hours). Only a few papers have examined a model involving ‘flexible’ operation of the capture facility in which the CO2 is captured at variable or reduced rates for all or part of a day, week, season or year. This paper presents an assessment of the operational opportunities for deploying flexible CO2 capture at black coal fired power plants located in the state of New South Wales (NSW), Australia. Different models of flexible capture including part-time operation, partial CO2 capture rates and a combination of both operating modes are examined. The results show that it may be possible to reduce the current CO2 emissions from NSW coal-fired power plants by up to 50% during summer while still meeting the state electricity demand. The estimated cost of CO2 avoided ranges from A$120 to A$190 per tonne avoided for flexible capture. [Copyright &y& Elsevier]

Abstract: Greenhouse gas emissions from industrial processes, such as cement manufacturing or steel production, in Australia accounts for more than 40 Mt CO2-e per annum, representing close to 20% of Australia’s potentially sequesterable emissions. Further, the emissions from these processes are highly concentrated in CO2 compared to the emissions from power generation. It is not clear if these higher concentrated gases may provide low cost options for demonstrating CO2 capture or if this benefit will be lost due to the smaller total volume of CO2 emissions of most industrial processes. Nevertheless, this sector of the economy requires further analysis. This paper will provide an overview of the emissions from Australian cement sector including both the emissions from the chemical process itself, as well as the associated emissions from energy use within those processes. Specific attention will be focused on the Australian cement industry. While CCS involves the integrated part of capture, transport and storage, the focus of this paper is on the capture side and will illustrate CCS options for the cement industry. [Copyright &y& Elsevier]

Abstract: Currently, Australia emits approximately 600 MT equivalent of CO2 annually, of which approximately 30% is directly linked to the electricity generation using both brown and black coals. To restrain the CO2 emissions, coal based power generators are looking to retrofit the existing power plants with commercially available technology for the post combustion capture (PCC) of CO2 as well as invest in the new power plants with high efficiency steam cycles. Since Australian coals are low in sulphur and the coal-fired power plants are well away from densely populated regions, the flue gas desulphurisation (FGD) and de- NOX regulations are currently not there for the coal based electricity generation in Australia. This is not an advantageous situation for straightforward retrofitting of the existing power plants with 30 wt% aqueous MEA based commercially available PCC technology that has very limited tolerance for SOX and NOX (less than 10 ppmv). In addition, Australia is a dry continent with very limited cooling water availability for the power plants. Hence, the Australian power generators are considering both the power and the post combustion CO2 capture plants to be air cooled. This paper, therefore, assesses the impact of introducing post combustion capture of CO2 on the existing and new Australian coal-fired power plants, both brown and black coal-fired, in terms of the cost of electricity generation, the cost of CO2 avoidance, the cooling water demand and the overall plant efficiency. The existing power plants are considered to be conventional subcritical and supercritical single reheat steam cycle based whereas the new power plant designs have allowed for ultracritical steam conditions (35 MPa, 922 K) with double reheat. The CO2 capture plants are considered to be either in service full time or in service on demand with 90% capture efficiency and the product CO2 ready for sequestration at 10 MPa and 313 K. The process and cost models for integrated power and capture plants have been obtained using ASPEN Rate-Sep, Steam-Pro, Steam-Master and PEACE software packages for process modelling and cost estimation. The results clearly show that an air cooled integrated power and capture plant has lower overall plant efficiency and slightly higher cost of electricity generation in comparison with a water cooled equivalent plant. An ultracritical single reheat power plant when integrated with capture plant that is in service full time has potential for lowest cost of electricity generation with minimum cost for CO2 avoidance. These results further show that replacing an existing turbine with a new LP turbine optimised for continuous steam extraction for CO2 plant duty minimises the adverse impact of PCC integration but the power generator looses the flexibility for electricity generation. The results also provide important insights into the major contributions to the increased cost of power generation. For both the existing and the new power plants, the amortised capital charge component dominates the cost of PCC integrated electricity generation. In spite of the large reduction in efficiency for Australian power plants when PCC is applied, it appears that reducing the capital costs of PCC will be at least equally important. This is an important outcome for the prioritization of research activities aimed at reducing the costs of capture. For example, the novel solvent development work for improved PCC technology should focus on increasing absorption rates at the same CO2 carrying capacity of the solvent to reduce the capital cost component. [Copyright &y& Elsevier]