After this lesson, you will be able to trace the flow paths of typical power plant combustion air and flue gas systems. You will also be able to describe the operation of major components within those flow paths. • Describe the individual flow paths of primary and secondary air • Compare the relative temperatures of the reheat and superheat boiler sections • Explain the use of forced and induced draft fans • Describe the function of the following flue gas system components: – Air preheaters – Scrubbers – Expansion joints