Duke Energy Florida (DEF) applied recently at the Florida Department of Environmental Protection for a Title V air permit revision for the Crystal River Energy Complex (CREC) that covers new hydrated lime injection systems for emissions control.
The application incorporates the conditions of a prior air construction permit associated with the permanent hydrated lime injection system into a revised Title V permit for the coal-fired Crystal River Units 4 and 5 (Crystal River North or CRN). In addition, the application requests incorporation of a final revised carbon monoxide (CO) best available control technology (BACT) limit into the Title V revision.
Crystal River Units 4 and 5 are fossil fuel-fired steam generators with dry bottom, wall fired boilers. The boilers are capable of burning bituminous coal, a bituminous coal and bituminous coal briquette mixture, and used oil. Air pollution control equipment for each unit includes: low-NOx burners, a selective catalytic reduction (SCR) system, an acid mist mitigation (AMM) system, an electrostatic precipitator (ESP), and a flue gas desulfurization (FGD) system.
The AMM system is used for the control of sulfuric acid mist (SAM) emissions and uses hydrated lime as the sorbent for primary control and ammonia injection as the method of secondary (backup) control.
In early 2011, DEF requested authorization for the temporary installation and operation of a demonstration injection system at Crystal River North using alternative sorbents to evaluate additional methods for reducing SAM emissions. Authorization was issued in May 2011. The utility was then authorized for a permanent hydrated lime injection system at Units 4 and 5.
“The construction activities that were authorized under this permit have now been substantially completed and compliance has been demonstrated,” the Nov. 15 application noted. The application was prepared for DEF by consultant Golder Associates. “Therefore, this application serves to incorporate the conditions of the air construction permit associated with the permanent hydrated lime injection system into a revised [Title V] permit for Crystal River Units 4 and 5.”
DEF selected hydrated lime as the best available sorbent because of ease of material handling, as well as the extent to which it has been used in the U.S. Hydrated lime has also been used on some of parent Duke Energy’s generating units in North Carolina with encouraging results.
“The use of hydrated lime, which has been successfully demonstrated at Crystal River, will also have the co-benefit of reducing the level of ammonia (NH3) in the fly ash,” the application said. “Eliminating the need for NH3 for SAM mitigation significantly reduces the amount of NH3 compounds retained with the fly ash. This has the benefit of improving handling and storage operations, as well as the beneficial reuse of the fly ash.”
This permanent system is proposed to be used in lieu of the current NH3 injection system for control of SAM emissions, although the current NH3 injection system will be retained for backup.
Crystal River Units 1 and 2 are in danger of shutting by April 2016
Crystal River Units 4 and 5 are larger and newer than the plant’s other coal units, which are Units 1-2. Unit 3 is a 789-MW nuclear facility that is about to be retired.
Units 1 and 2, may get retired as soon as April 2016 due in part to the federal Mercury and Air Toxics Standards (MATS). But Duke Energy Florida has said it may be able to extend the lives of these two units to 2020 if test burns of new coal this year in those units pan out. Units 4 and 5 at Crystal River are equipped with new-ish emissions controls, like the FGDs, and are not in danger of shutting.
Under the terms of a revised air permit, Crystal River Units 1 and 2 are required to cease coal-fired operation by the end of 2020 unless scrubbers are installed prior to the end of 2018.
Crystal River Units 1 and 2 have traditionally been fired with Central Appalachia coal. U.S. Energy Information Administration data shows that the plant got its coal earlier this year from various suppliers, including B&W Resources, Arch Coal Sales, James River Coal and Alpha Natural Resources. The test blends of coal this year at these units are of western bituminous and Powder River Basin coals. Units 4 and 5, which have SO2 scrubbers, burn high-sulfur coals from the Illinois Basin from suppliers like American Coal and Knight Hawk Coal LLC.
The coal units and their net capacities at Crystal River are: Unit 1 – 376 MW; Unit 2 – 497 MW; Unit 4 – 727 MW; and Unit 5 – 706 MW.