|Ultra High Efficiency Power Generation from Victorian Coals|
|By Louis J Wibberley, Leader, Advanced Carbon Power, CSIRO Energy Technology|
|Right: MRC from Exergen Yallourn CHTD|
|The Direct Injection Carbon Engine (DICE) represents a major step towards a baseload energy technology that has low capital cost, high efficiency, low greenhouse gas emissions and provides quick stop/start/ramp times. |
DICE can be used with any carbon-based fuel source, including both renewable and fossil fuels, and can provide back up for intermittent energy sources, such as solar and wind, or provide peaking power to complement fixed-load power stations. DICE also has the potential to provide a synergistic fit with carbon capture technologies.
Victorian brown coal has proven to be an ideal fuel source for DICE. The DICE technology involves producing a low ash coal water slurry (a micronised refined carbon or MRC).This is injected into specially adapted large diesel engines where it burns in a manner similar to heavy fuel oil, at a significantly higher thermal efficiency than existing power stations.
DICE has the potential to become an alternative power generation technology to produce low cost, low CO2 electricity from Victoria’s world-class coal reserves.
This article summarises RD&D undertaken with Brown Coal Innovation Australia over the last three years towards a DICE demonstration in Victoria.
|The BCIA funded research program has assessed the suitability of a range of separation technologies for controlling the amount and size of mineral particles in the MRC, strategies for controlling fuel rheology, atomisation, combustion, techno-economics, and integration of CO2 capture technologies.|
Better-than-expected results have been obtained across all research areas. Highlights of the RD&D program to date include:
- Hydrothermal processing is the preferred method of preparing the fuel. Hydrothermal processes are well known to Victoria, with development dating back to the late 80s and the SECV’s 24 t/day pilot plant at Mulgrave. More recent pilot scale development has been by Exergen and Ignite Energy Resources. JGC has also recently commissioned a 24 t/day pilot plant near Jakarta for upgrading Indonesian lignites. Larger hydrothermal plants are in operation in China.
- An important sub-process has been de-sanding to ensure a consistent MRC quality with respect to coarse mineral content. Good results have been achieved using inexpensive conventional coal processing spirals.
- The brown coal MRC has high energy and a viscosity low enough for injection. Atomisation of the fuel is complete in around 1ms, and ignition is also very rapid (around 5ms), providing excellent combustion under simulated engine conditions.
- Higher viscosity/solids fuel mixtures have shown better ignition properties, highlighting the need to develop improved atomisers to handle these viscous fuels. A novel air blast injection system has been developed for brown coal pastes that gives excellent atomisation of paste with low air consumption.
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