DICE technology

DICE is a technology that could yield lowest cost energy security with a step reduction in carbon emissions, by providing:

  • The highest thermal efficiency of any heat engine, especially at smaller unit scale.
  • Most flexibility to underpin a high penetration of renewables, directly via efficient utilisation of biomass carbons, and indirectly via providing cost effective backup and grid security.
  • Potential for the most energy efficient and cost effective implementation of CO2 capture to allow carbon storage as the last step in meeting emissions targets.

Alternative pathway to low carbon emissions

Alternate pathway to ultra-efficiency low CO2 power generation
Alternative pathway to ultra-efficiency low CO2 intensity power generation

Overall, the DICE fuel cycle provides an alternative technology pathway to a 50% reduction in carbon intensity for power generation in the short to medium term. It is envisaged that niche, rather than major, CCS would be employed as the final step in meeting carbon emissions targets.

DICE fuel cycle

The current DICE fuel cycle is based on incremental improvements to the cycle developed during the extensive USDOE program over 1978-92, and more recent developments by the CSIRO and partners: Exergen, Ignite Energy Resources and the BCIA for brown coals, and Yancoal, Newcrest and Xstrata for black coals.

For black or bituminous coals, the preferred fuel cycle involves micronising the coal (fine milling to give a top size of around 50 µm), followed by deashing, trim dewatering, and homogenising with the aid of a dispersant to form MRC. The process steps are shown graphically below.

DICE fuel cycle with black coal
DICE fuel cycle with black coal

For brown coals, processing also includes a densification step (eg hydrothermal treatment) aimed at decreasing the water contained within the pores of the coal – thereby increasing the specific energy of brown coal MRC. The process steps are shown graphically below.

DICE fuel cycle with brown coal
DICE fuel cycle with brown coal

Implications for coal

From a coal industry perspective, DICE would create new markets for domestic and export thermal coals. Opportunities are being pursued for both black and brown coals.

For black coals, there is the option of recovering MRC economically from coal washery rejects and higher ash bituminous coals – thereby increasing resource recovery and reducing disposal costs.

For brown coals, MRC provides the potential to export brown coals as MRC paste, noting that brown coals are not currently exported because unprocessed they contain too much water, and dried they are pyrophoric and difficult to ship – even as briquettes.

Another potential new market (interest by Maersk, D/S Norden and SEACO) is fuelling the global deepwater shipping fleet with coal - a market of around 250 Mtpa carbon equivalent. With only a small amount of biochar co-firing, a carbon footprint below that of fuel oil can be achieved, but at significantly reduced cost . This also applies for remote area power generation applications (ie alternative to fuel oil or diesel for isolated island communities or remote mine sites away from large power grids).

The cost and energy for MRC processing is more than offset by these benefits.

From the fuel production side, while the technologies involved are well known to the coal industry, the fuel cycle is new, and requires broad development – a key objective of DICEnet.

It is noted that, during the last five years, the production of coal water fuel for boilers in China has more than tripled to a +100 Mtpa industry, and, while lower quality than the MRC required for DICE, this expansion provides a good analogue and market entry for the DICE fuel cycle.