IMPROVING THE ENERGY EFFICIENCY OF A MID-SIZE POWER PLANT BY REDUCTION IN AUXILIARY POWER AND IMPROVED HEAT TRANSFER

• Main Author: Green, Jeffrey Andrew
• Format: Others
• Published: OpenSIUC 2014
• Subjects: Coal; Flue Gas Heat Recovery; Heat Transfer; Low Grade Energy Use; Power Plant Efficiency; Variable Frequency Drives
• Online Access: https://opensiuc.lib.siu.edu/theses/1502; https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=2516&context=theses

This study incorporates the potential use of Variable Frequency Drives on various motors as well as areas of improved heat transfer in an older, mid-sized coal fired power plant. In power plants, fluid flow rates are often controlled using dampers or valves while the motors that power the pumps stay at full speed resulting in a significant amount of wasted electrical power; energy is also lost due to poor heat recovery prior to gases leaving the system. By examining pump usage as well as additional heat available for recovery, potential energy savings will be determined. Preliminary results of five motors suggested for variable frequency drive application show annual savings that total 31.1 GWh, resulting in a 1.66% increase in overall plant efficiency. Total project costs are near $2 million resulting in a simple payback period of less than two years assuming 0.04 $/kWh. For every degree reduction of the flue gas temperature by means of heat recovery that is reused elsewhere in the cycle, 2 Billion BTU of coal would be saved annually. One realistic scenario suggested heat recovery resulting in a 120°F degree reduction of flue gas temperature amounting to a 2.54% increase in cycle efficiency.