Project Summary
Oxy Combustion is one of the coal-based candidates for carbon capture and storage. As part of developing the Oxy Combustion technology, the environmental, health, and operational risks associated with trace elements need to be understood.
The focus of this research was to investigate the behaviour of trace elements during Oxy Combustion (oxy-firing) and CO2 capture and processing. The environmental and operational risks associated with trace materials was to be the primary focus of this work. It is understood that the behaviour of trace components may have important implications for process options, gas cleaning, environmental risk and the resultant costs of Oxy Combustion.
This study was based on a field experiment carried out at the retro-fitted Callide A power plant in December 2012. The power plant is capable of both oxy and air firing and the experiment involved both modes. Measurements were made of the trace metal and particulate matter emitted during the firing process, and the targeted metals included both mercury and chromium.
Key conclusions:
- The trace levels of metals in the purified CO2 gas stream should not pose significantly higher operational risks within the CPU;
- Oxy-firing does not pose significantly higher environmental or operational risks than air firing;
- Levels of metals, SOx and mercury are below levels of concern in the CPU, beyond the first low pressure scrubber, and
- Mercury levels, measured in CPU produced gas, approach those measured in ambient air. However, in all cases the increased risks to the population of exposure were below the USEPA response level, such that no action would be required to reduce exposures.
