Contact us on
+61 3 9565 9888

Mill Optimisation

Importance of Milling

Influence on Mill Performance on Combustion and Boiler Performance

  • Milling performance is critical in controlling the combustion process in the boiler;
  • Coal pf fineness influences:
    -ignition delay;  
    -combustion efficiency;
    -particle erosion;
    -loss on ignition (and hence coal costs);
    -value of ash and ability to dispose / sell;
    -emission levels;
    -boiler slagging and fouling;
    -potential damage to superheater tubes from combustion delay;

Need for Testing

  • Mill maintenance costs are one of the highest maintenance costs in a coal fired power station;
  • Testing allows a change to 'condition based' maintenance (from set mill operating hours) which in HRL's experience can increase time between minor / major mill overhauls by up to 10%;
  • Optimising milling performance can reduce coal consumption and therefore costs;
  • Testing can help detect mill performance issues early and can help direct / target maintenance activity.

Broader HRL Mill Performance Capability

The EUcoalsizer fits into HRL's broader mill performance service offer to assist in optimising- mill performance.

  • Measurement of pf flow per burner duct microwave technology;
  • Coal flow balancing (e.g. by adjustment of values on PF pipes);
  • Check / calibration of coal flow obtained from volumetric or gravimetric coal feeder to mill and check on mill capacity limits (and assessment of reason for limits);
  • Mill power consumption (per unit of coal throughput) including as a check on classifier recirculation rates;
  • CFD modelling of milling system to solve flow related issues;
  • Adjustment of classier vane setting or redesign to adjust pf fineness;
  • Mill condition and inspection;
  • Measurement of pressure drop across mill / classifier;
  • Mill performance as a function of load / coal throughput;
  • Measurement of PA flow / auxiliary air / mill seal air flowrate;
  • Comparison of measurements against station instruments;
  • 'Clean' (no coal flow) testing to measure air flow distribution to burners;
  • Assessment of individual mill performance and recommendations for maintenance, physical modifications, or operational changes;
  • Measurement of mill inlet / outlet temperature, and check on temperature stability;
  • Testing of mill performance following major overhaul to demonstrate performance gain and to help optimise future overhaul scope of work;
  • Assessment of materials, failure analysis, requirement for repair or replacement.

Introducing the EUcoalsizer

EUcoalsizer Features

  • Measures (in real time) pf particle size distribution (PSD), coal and air flow;
  • Provides spatially resolved (2D) readings;
  • Allows real time coal : air flow tuning and adjustment of coal feeders / mill control settings;
  • Requires larger 3" ports to be installed.

Benefits of EUcoalsizer

  • Cost of testing is dramatically reduced.  Testing is conducted by a single operator;
  • The cost competitiveness allows regular e.g. quarterly or bi-annual testing of all mills;
  • This in turn facilitates moving to a 'condition based' maintenance program and hence a reduction in mill maintenance cost, as well as prioritising mill maintenance to optimise combustion performance;
  • Allows milling performance to be characterised following a change in coal supply (or evaluation of suitability of a particular coal supply);
  • Allows real-time assessment of changes to mill operation and settings on pf size and hence adoption
  •  of a mill operation optimisation program;
  • Optimising mill performance can result in reduction in coal consumption, carbon in ash and allows full benefit to be obtained from combustion tuning.

 

Meet the expert
 

ANDREW JAMES

Over 6 years' experience in providing technical and engineering support for industrial and utility boilers. This includes a specialization in combustion optimisation of large power station boilers through onsite measurements and the tuning of combustion control systems. Read more

 

News and
Events

Read All news

HRL delivers energy and cost savings for Stone and Wood via the OEH

Mar 20 2017
Elected by the NSW Office of Environment and Heritage (OEH) as a member of the Energy efficiency professional service panel, HRL has delivered a...

New roles at HRL

Feb 28 2017
HRL grows with new positions Contract Position - Melbourne, Analytical Chemist - See Job Ad We are seeking expressions of interest for e...

Gold and Silver Concentrations

Feb 27 2017
Marius Harmse is our expert Senior Chemist and contributed to an article in Chemistry a European Journey and pulished on Wilely's Online Lib...