This paper examines the effects of particle size on the calorific value of hydrocarbons, shedding light on the thermodynamics of pulverizing coal in a commercial power plant. Both laboratory testing results and energy balances around an actual pulverizer are presented. Although tacitly known to any power plant engineer, efficient combustion is seen in two parts: preparation of the material’s surface/mass ratio, and then its combustion with the proper air/fuel mix and associated mechanics. This work attempts to put a thermodynamic face on the first part. A theory is presented which demonstrates that a hydrocarbon’s surface/mass ratio affects its potential to release its full chemical energy. This theory has been generally supported in this work by laboratory testing of pure substances; however this testing was not conclusive and should be repeated. If an optimum surface/mass is not achieved, unburned combustibles will result — and this regardless of subsequent air/fuel mixtures and/or burner sophistications. This work is suggests that a unique optimum surface/mass ratio exists for each hydrocarbon substance (and coal Rank); that once its full potential is reached, a higher ratio provides no further benefit. Since surface tension describes a material’s free energy, an aspect of surface tension, termed hydrogen bonding free energy, was shown to relate to the A¨calorific value penalty associated with non-optimum surface/mass ratio. A correlation was developed relating surface/mass ratio to observed an A¨calorific value penalty and hydrogen bonding free energy. This correlation’s form may be applied to coal if supported with additional research. The impetus for this work was the ASME Performance Test Code 4’s allowance of pulverizer shaft power to influence boiler efficiency’s “credit” term, thus affecting efficiency. It was demonstrated that surface/ mass affects calorific value and thus efficiency. However, there is no observable difference between grinding a hydrocarbon to a given surface/mass ratio, versus manufactured spheres. Although laboratory preparation of coal samples should emulate pulverizer action, this work suggests that a renewed and careful review of laboratory procedures is required. Recommendations are provided for critique and debate.
Skip Nav Destination
ASME 2011 Power Conference collocated with JSME ICOPE 2011
July 12–14, 2011
Denver, Colorado, USA
Conference Sponsors:
- Power Division
ISBN:
978-0-7918-4460-1
PROCEEDINGS PAPER
Effects on Boiler Efficiency Standards of Pulverizing Coal
Fred D. Lang,
Fred D. Lang
Exergetic Systems, Inc., San Rafael, CA
Search for other works by this author on:
Tim Golightly,
Tim Golightly
Portland General Electric, Boardman Coal Plant, Boardman, OR
Search for other works by this author on:
David A. T. Rodgers,
David A. T. Rodgers
Portland General Electric, Boardman Coal Plant, Boardman, OR
Search for other works by this author on:
Tom Canning
Tom Canning
Consulting Engineer, Dublin, Ireland
Search for other works by this author on:
Fred D. Lang
Exergetic Systems, Inc., San Rafael, CA
Tim Golightly
Portland General Electric, Boardman Coal Plant, Boardman, OR
David A. T. Rodgers
Portland General Electric, Boardman Coal Plant, Boardman, OR
Tom Canning
Consulting Engineer, Dublin, Ireland
Paper No:
POWER2011-55216, pp. 707-719; 13 pages
Published Online:
February 28, 2012
Citation
Lang, FD, Golightly, T, Rodgers, DAT, & Canning, T. "Effects on Boiler Efficiency Standards of Pulverizing Coal." Proceedings of the ASME 2011 Power Conference collocated with JSME ICOPE 2011. ASME 2011 Power Conference, Volume 2. Denver, Colorado, USA. July 12–14, 2011. pp. 707-719. ASME. https://doi.org/10.1115/POWER2011-55216
Download citation file:
13
Views
Related Proceedings Papers
Related Articles
Thermodynamic Analysis and Comparison on Oxy-Fuel Power Generation Process
J. Eng. Gas Turbines Power (September,2009)
Advanced Coal-Fired Power Plants
J. Energy Resour. Technol (March,2001)
Fine Particulate Formation During Switchgrass/Coal Cofiring
J. Eng. Gas Turbines Power (July,2005)
Related Chapters
Physiology of Human Power Generation
Design of Human Powered Vehicles
Combined Cycle Power Plant
Energy and Power Generation Handbook: Established and Emerging Technologies
Energy Options and Terms: An Introduction
Energy Supply and Pipeline Transportation: Challenges & Opportunities