1. Optimizing fuel flow in pulverized coal and biomass-fired boilers Malgorzata (Maggie) Wiatros-Motyka EUEC2016 3-5 February 2016, San Diego, USA.

2. Why optimize fuel flow To improve plant efficiency To reduce emission To reduce maintenance To lower operating costs To eliminate safety hazards To increase fuel flexibility

3. Opportunities for improvement Verification: Temperature O 2, CO, NOx LOI Coal and air flow to individual burners Coal feed rate to mills and fuel fineness Primary air Secondary air OFA Air/fuel ratio and fuel distribution *Image: modified from Combustion Technologies/ AMC POWER

4. Optimization starts in the mill *Image: Storm Technologies Inc.

5. Coal fineness measurement Fuel fineness requirement: 75% ≥ passing 74µm & ≤0.1% retained on 294µm Traditional extractive vs advanced non-extractive techniques Important factors (sampling location, representative sample – sampling all lines of each mill, analysis time)

6. Mill optimization  Keeping all elements in good condition  Keeping ‘the distance’ & balancing the load  Setting the correct throat clearance  Maintaining the classifier *Images: Storm Technologies Inc.

7.  All air flows (PA, SA, OFA) need to be measured and controlled  Traditional vs. advanced measurement  New technologies range from advanced pitot tubes through electrostatic based systems to virtual and optical sensors. Air flow measurements

8.  Isokinetic vs advanced measurements  Commercially available advanced flow measurement technologies (electrostatic and cross correlation, microwave, laser, acoustic emission)  Flow distribution and rope breaking devices  Important factors in choosing the right technology Fuel flow measurement and control Images: top – Greenbank’s VARB®,

9.  Carbon in ash, O 2 & CO (and other) measurements can verify fuel flow optimization as well as be useful tools leading to adjustment, control and air/fuel flow optimization  Advances in carbon in ash technologies  What is important before choosing the appropriate technology Verification of fuel flow optimisation

10.  Improvements in efficiency  Fuel cost savings  Emission control  Increased sale of fly ash  Safety hazards elimination  Improved performance of emission control equipment Case studies - typical gains

11.  Advanced fuel flow technologies are more accurate than traditional ones and yield greater benefits  When choosing appropriate technology many factors need to be taken into account  Optimization results depend highly on the pre-optimization conditions and are very case specific.  ‘If you cannot measure, you cannot control. If you cannot control, you cannot optimize’ (F. Turoni). Conclusions

12. Thank you Malgorzata.Wiatros@iea-coal.org The IEA CCC Report ‘Optimizing fuel flow in pulverised coal and biomass-fired boilers’ is available from www.iea-coal.org.uk