Post-combustion demonstration

Post-combustion capture (PCC) at the Hazelwood power plant

This project will allow CO2CRC to leverage the existing research base of its capture activities in Victoria. The University of Melbourne is responsible for developing solvent and membrane technologies while Monash University performs R&D on adsorbents. CO2CRC will test these technologies in a 25 tpd PCC unit at Hazelwood of International Power. The key objective is to reduce the technical risk and cost of PCC for Victorian coal-fired stations.

The project aims to :

• determine the effects of operating parameters of CO2 concentration, moisture content, SOx and NOx concentration and fly ash properties on the behaviour of sorbent systems and other novel separation technologies;
• assess a post-combustion capture process and energy integration options for Hazelwood Power Station; and
• review of the technical and economic viability of the commercial use of pos-combustion capture for existing and new Victorian brown-coal power stations.

PCC has the advantage that it can be retrofitted to existing plants, integrated into new plants, has high operational flexibility in that it can be added in stages and operated independently of the power station and, importantly for this project, has significant development potential through process improvements, new sorbents and new technologies.

Background for capture projects

Brown coal is the cheapest source of fossil fuel for power generation in Australia, but it produces the highest level of greenhouse gases when burned in conventional boilers in power plants. To ensure their viability in the longer term in the world, where greenhouse gas driven climate change is an accepted fact, we should be looking at ways of

Making coal burning more efficient 

It can be accomplished in many different ways, such as overall energy integration in the power plant and/or adopting new technologies. Coal gasification is one of the best methods of efficient burning at high pressure and temperature. Advanced technologies such as Integrated Gasification Combined Cycle (IGCC) and Integrated Drying Gasification Combined Cycle (IDGCC) will enable higher thermal efficiencies - up to 50% in the future. However, in the current carbon-constrained world, the viability of coal-fired plants can only be ensured if efficiency measures will be accompanied by the following activity.

Sequestration of the waste carbon dioxide

It involves capturing carbon dioxide from flue gases and then to compress and inject underground. Carbon dioxide can be captured from flue gases either after (post-) or before (pre-) combustion in a power station using a range of capture technologies as explained below. Pre-combustion capture is more suitable for plants having new coal burning technologies (IGCC, IDGCC).

1. Solvent absorption – when flue gas is passed through, liquid chemicals can absorb carbon dioxide and can then release it at elevated temperature in another vessel. So the same chemical can be used over and over again to perform the separation of carbon dioxide.
2. Adsorbents are solids that have the capacity to capture carbon dioxide on their surface, which can be reused in a cyclical process
3. Membranes like filters to separate one gas from another in a mixture. Membrane gas absorption (MGA) is a hybrid of membrane and solvent separation that seeks to exploit the advantages of both processes

Ultimately, the technical and economic viability of the commercial use of capture technologies for existing and new Victorian brown coal power stations will be reviewed and reported based on the R&D programs outlined below.