The IEA Greenhouse Gas R&D Programme commissioned a study to confirm the projected costs for CO_2 capture using oxy-combustion technology as applied to new-build power generation plant. The study covered the following greenfield power generation plant with CO_2 capture:- 1. Advanced Supercritical Bituminous Pulverised Fuel (PF)-Fired Power Plant 2. Natural Gas Combined Cycle (NGCC) Power Plant In compliance with the IEA GHG study specification, the target net power output of the power plant was aimed at 500 MW_e. To represent a reasonable baseline of oxy-combustion, the process evaluation was based on proven technology, where possible, with oxygen production based on cryogenic separation technology and the recycle system utilising either flue gas or CO_2. Process flow diagrams (PFDs) were developed and heat and mass balances (HMBs) compiled to model the overall oxy-combustion process. For the PF-fired power plant case, the recycle system took into consideration dust loading and milling plant requirements. Consideration was also given to possible integration opportunities and heat and power utilisation to maximise plant efficiency. Optimised plant performance parameters were used for cryogenic air separation with 95% v/v O_2 purity to suit the required CO_2 purity of 95% v/v with recognition of excess combustion oxygen and furnace/boiler tramp air ingress for the PF-fired power plant case. The PFDs/HMBs analysis produced data which allowed specifications for the major plant items to be developed; this in turn allowed budget capital costs for the major components to be assessed and operating philosophies to be investigated. The appropriate gas clean up technologies were identified to meet the target minimum CO_2 purity of 95% mol @ 110 bara. This included a review of available processes, and the impact of the processes on the resulting flue gas quality with reduced specific contaminants such as SO_2 and O_2. Aspects of the oxy-combustion process which impact on the safety and operability of the power plant were also highlighted in the study. Finally an economic analysis was performed similar to that undertaken on IGCC power generation by the IEA GHG Programme to arrive at the power cost per kWh. The basic cost elements being capital cost, operating cost and agreed economic parameters. A sensitivity analysis was undertaken to compare the influence of discount rate and fuel costs on power costs.
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