Pre-combustion demonstration

CO2CRC Mulgrave Capture Project

Background

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 its viability in the longer term , where greenhouse gas- driven climate change is an accepted fact, we should be looking at ways of making coal burning more efficient.

Improved efficiency can be accomplished in many different ways, such as overall energy integration in the power plant and/or adopting new technologies. Coal gasification at high temperature and pressure is one of the best routes to more efficient burning.

Advanced technologies such as Integrated Gasification Combined Cycle (IGCC) will enable higher thermal efficiencies - up to 50 per cent in the future - through a combined cycle which uses a gas turbine followed by a steam turbine to generate electricity.

Pre-combustion CO2 capture is highly suitable in plants with new coal burning technologies such as IGCC as they have a concentrated CO2 stream. In the gasification process, coal is brought into contact with air, making a combustible gas of mostly hydrogen and carbon monoxide (known as syngas). Syngas contains a reasonable amount of CO2 and a significant amount of nitrogen from the air used. This gas mixture is the feed gas for the capture plant.

Pre-combustion capture trials at HRL’s research gasifier, Mulgrave

The key objective of this project is to reduce the technical risk and cost of pre-combustion capture for Victorian coal-fired stations with new coal burning technologies employing gasification.

The trials will evaluate pre-combustion CO2 capture technologies to identify the most cost-effective for application to coal gasification power-generation technology. This project will also 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 adsorption technology.

In more detail, the program will:

• Identify and quantify the impact of realistic pre-combustion gas contaminants (H2S, CH4, CO) and water on the performance of each of the separation technologies;
• Identify and quantify the impact of pre-combustion gas temperature and concentration variations on the performance of the separation media and separation processes;
• Optimise process operating parameters;
• Develop engineering solutions at a scale at which confidence can be established for full scale plant design and assessment;
• Assess the pre-combustion capture process and energy integration options; and
• Review the technical and economic viability of the commercial use of pre-combustion capture for new Victorian brown-coal power stations using the gasification process route.

The capture technologies under evaluation are:

	Solvent absorption – the most mature technology and currently the method of choice for CO2 separation in industry globally. Find out more
	Membrane separation – a promising stand-alone technology that can also be integrated with solvent systems. Find out more
	Pressure swing adsorption – a new technology that captures CO2 using fixed beds of solid material and releases it by pressure changes. Find out more

Future applications

The technology found in the preliminary trials to be most cost-effective could then be subjected to further trials, including:

• Trials at plants which include extra process steps to maximise the CO2 capture. These steps involve further reacting the syngas with water to produce hydrogen and CO2 (a water gas shift reaction or WGS). The CO2 is captured and the hydrogen can be used in a gas turbine or a fuel cell to produce power.
• Trials in a gasification plant where oxygen has been separated from air before being used in the gasifier.

While the preliminary trials will be conducted without a water gas shift and at a lower operating pressure than in a full scale coal gasification power plant, experimental data from the trials combined with numerical modelling enables an assessment of the separation performance of each technology against commercial plant conditions.

Results, September 2009

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Solvent absorption
	CO2CRC researchers are using this solvent rig to evaluate and improve solvent technologies for separating carbon dioxide from syngas during the CO2CRC/HRL Mulgrave Carbon Capture Project.
	Solvent absorption is one of three carbon dioxide separation technologies being evaluated through the CO2CRC/HRL Mulgrave Carbon Capture Project.
	Solvent-based absorption CO2 capture.
Membrane separation
	During the CO2CRC/HRL Mulgrave Capture Project CO2CRC researchers will use three innovative new technologies in an evaluation of pre-combustion capture of CO2. Pictured here is the membrane rig, on the left, and the adsorption rig, right.
	CO2CRC researcher Dr Colin Scholes, from the University of Melbourne, adjusts the membrane rig that is part of the Australia's first pre-combustion carbon capture project - the CO2CRC/HRL Mulgrave Capture Project.
	Membrane gas absorption: hollow fibre module.
	Gas separation membrane: flatsheet module.
Pressure swing adsorption
	CO2CRC researcher Kaustubh Joshi, from Monash University, adjusts the adsorption rig that is part of the Australia's first pre-combustion carbon capture project - the CO2CRC/HRL Mulgrave Capture Project.

More images
Post-combustion demonstration
Storage demonstration at the Otway Project