Download
1 / 25
280 likes | 476 Vues
MTE – Mechanical Thermal Expression. Dewatering Process for Brown Coal Malcolm McIntosh Roland Davies APP Brown Coal Best Practice Workshop 25 June 2008. Drying/Dewatering Technologies. Why significant? >15% of coal energy to evaporate water
E N D
MTE – Mechanical Thermal Expression Dewatering Process for Brown Coal Malcolm McIntosh Roland Davies APP Brown Coal Best Practice Workshop 25 June 2008
Drying/Dewatering Technologies Why significant? • >15% of coal energy to evaporate water • High moisture content therefore gives high CO2 emissions Efficient coal drying/dewatering: • Lower CO2 emissions • Lower capital cost of new plant • Improvement in coal quality (dewatering) • Water capture potential Currently no commercial plant has pre-drying • More conventional drying technologies may well be suitable for smaller scale industry requirements
MTE Dewatering • Concept of dewatering by pressing known since 1950s • Strauss (University of Dortmund) demonstrated dewatering with lower mechanical pressures at elevated temperature in 1990s (MTE) • Potentially MTE has advantages over drying of • Energy efficiency • Water capture • Inherent cleaning of water soluble compounds from the coal
Batch System - German Arrangement tcycle= tfeed + theat+ tdewater+ tdischarge Pilot Plant Press area 1.3m2 Specific Throughput 2 T/(m2hr) Cycle time 9 min (7 min heating) Basis for scaling-up to 25 T/hr => Press area of 12.5 m2
Moisture Content as Function of Time (German) Pilot Plant data
MTE Technology Development • MTE process demonstration by RWE at large scale in 2001 using a plant based on a particle board press – considered unsuccessful • CRC for Clean Power from Lignite demonstrated operation of a nominal 1 tonne/hr plant in 2002 • Funding support was obtained from the Commonwealth Government (AGO) and Victorian Government (DPI) in 2006 for a demonstration plant with a nominal 15 tonne/hr coal throughput. The project, which had a budget of $6.4m, has been funded by government in partnership with the brown coal generators. • The plant was constructed in 2007 and commissioning completed in April 2008. The plant is currently being tested.
MTE Plant • Confirm process performance • Demonstrate reliable continuous operation • Provide data and cost information for design of commercial plant. • Provide larger samples for coal and water analysis.
MTE Pilot Plant 20 Jun 08, Test 1 Top platen position Water removed Applied pressure Product Bottom platen position
Conceptual Stand-alone MTE Plant Raw Coal Heat losses Cooled water effluent Heat recovery Airheater Saturated steam MTE Plant Hot effluents Process Steam Boiler Crusher Humid air discharge Fluidised Bed Cooler Dewatered product ~30% wb Dewatered Product to fuel Boiler Air
MTE PILOT PLANT 15tph MTE PROJECT OBJECTIVES: • Confirm process performance (throughput and product moisture content) • Demonstrate reliable continuous operation • Provide design data and cost information for commercial scale demonstration plant • Provide larger samples of product coal and water for analysis and testing PROJECT STATUS: • Construction completed: Q3 - 2007 • Commissioning completed: Q1 - 2008 • Test Programme commencement: Q2 - 2008
BROWN COAL SPECIFICATIONS Moisture (% as received) 60 – 65% Ash (% db) 1.5% Volatile Matter (% db) 51.3% Carbon (% db) 67.0% Hydrogen (% db) 4.7% Sulphur (% db) 0.38% Sodium (% db) 0.13% Energy - NWSE (MJ/kg) 8.1 MJ/kg Energy - GDSE (MJ/kg) 27.0 MJ/kg Brown Coal - Water you can Walk on!
Where to Next (contd) 200 T/hr Demonstration Plant • Stand-alone plant • Product to existing power stations • Funding ?
