High Efficiency Low Emission Pilot-Scale Evaluation and Pecan Nut Shell Biochar Addition to Australian Coals for Thermal Uses

Current strategies to reduce the carbon intensity of coal-fired power generation focus on two key areas, viz. (a) the deployment of High Efficiency, Low Emissions (HELE) power plants and (b) the co-firing of biomass with coal.  The ALS combustion test facility was originally designed and constructed in the 1980s, and while it mimicked contemporary coal-firing practices at that time, it could not replicate the conditions prevalent in HELE power plants nor cofire biomass-derived fuels.

Under this project, ALS undertook substantial upgrades on its combustion test facility, to replicate the conditions in HELE power plants and to add the ability to co-fire biomass derived fuels with coal.  The upgrade took place in three stages:

• A feasibility study;
• An implementation phase; and
• A commissioning study.

The commissioning study was conducted by evaluating the performance of two coals, with and without biomass co-firing.  The conditions were as follows:

• A baseline (subcritical) test on each coal;
• A test on each coal under supercritical (HELE) conditions; and
• A test on each coal with a 10% biomass derived material substitution under HELE conditions.

The upgrades of the ALS facility provide the Australian coal industry with a robust platform for evaluating coal and biomass blends under advanced combustion conditions, supporting efforts to reduce greenhouse gas emissions and transition toward net-zero targets.  Recommendations include further research into ash deposition effects of other biomass materials and strategies to address ESP performance reduction during biomass co-firing.