Notes from Site Visit at TECO Energy’ s Polk Power Station on October 8, 2009

EPA conducted a site visit at TECO Energy’s Po lk Power Station (Polk) located in South Mulberry, FL on Thursday, October 8, 2009 to learn about the operati ons at the plant, specifically the integrated gasification combined cycle (IGCC) unit. Table 1, located at the end of this memorandum, identifies th e site visit participants. The presentation that the Polk personnel gave during the site visit is provided as Attachme nt 1 to this memorandum.

This memorandum describes the information collected during the site visit and the pre-site visit phone call, which was held on October 2, 2009.

Plant Overview

TECO personnel provided an overview of operations for Tampa Electric Generation, as shown in Attachment 1. This memorandum focuses on operat ions at the Polk Powe r Station. Attachment 2

contains an overall water ba lance diagram for the plant.

 Polk currently operates five electric gene rating units at the power plant, with a gross generating capacity of 920 MW. Th e table below contains some general information for the five generating units.

Unit Installation

Date Gross Capacity (MW) Unit Type Fuel Type

1 1996 320 (250 MW net) Integrated Gasification Combined Cycle (IGCC) –

base load Syngas generated from coal and petroleum

coke/distillate oil 2 2000 150 Simple cycle combustion

turbine Natural gas/distillate oil

3 2002 150 Simple cycle combustion

turbine Natural gas/distillate oil

4 2007 150 Simple cycle combustion

turbine Natural gas

5 2007 150 Simple cycle combustion

turbine Natural gas

 The Polk plant comprises over 4,000 acres (of which 750 acres comprises the cooling pond) and currently employs 80 people.

 Cooling water for the plant is suppli ed by a 750-acre unlined cooling pond. Cooling water recirculates from the pro cess to the pond. Due to evaporation, well water is used to makeup water to the cooling pond. Periodically, water from the cooling water is discharged to the Little Payne Creek, due to dissolved solids that build up in the pond or due to extreme rainfall events. The cooling pond also receives treated water from the slag runoff retention basin, the oily water collection and treatment system, and the storm water collection system.

 The Polk site was previously mined for phosphate.Page 2

Unit 1 IGCC Operations

 The gasification technology used at Polk was originally developed by Texaco and is now owned by GE.

 The current plant configurat ion consists of a single train, with one gasifier supplying one combustion turbine.

 Saturated steam created in the gasifier is pumped to the Heat Recovery Steam Generation (HRSG) unit and used to power a steam turbine.

 Syngas from the gasifier is processed and cleaned before being used to power the

combustion turbine. Diluent nitrogen is combusted with the syngas to reduce NOx

formation.

 The plant uses 2,200 tons per day of fuel. Current fuel is a blend of 30% coal and 70% petroleum coke. The stati on has experimented with use of several fuel blends comprised of various coals and petroleu m coke, and has also included various biomass blends as well. Low rank fuels, wh ich can be used in slurry fed gasifiers, lower the overall efficiency of the unit.

 Coal is received via covered truck, bottom dumped onto a conveyor, and stored in one of two 5,000-ton silos. The plant can hold approximately 5 days of fuel on site. Approximately 95 trucks per day are received at full capacity.

 The plant stores slag generated in the gasifi er in an outdoor lined pile. The slag is either marketed offsite (in the cement i ndustry or used as a fuel component at Tampa Electric’s Big Bend Station) or it is fed with the coal to the slurry preparation rod mill. Polk has also period ically transferred slag to an off-site landfill for disposal.

 Runoff from the slag pile is collected in two runoff basins, which are designed to hold the volume for a 100-year 24-hour storm event. The runoff is sampled 2 times per year. Leachate from the runoff basi ns is held in a leachate pond, prior to filtration and discharge to the cooling pond. The slag pile bottom liner is 60 ml and top liner is 80 ml. Leachate from the slag storage area is sampled and analyzed on a semi-annual basis. The most recent sample was collected in May, 2010. The laboratory report for this samp ling event, which lists all pollutants analyzed as well as the test result s, is included as Attachment 3.

 Coal and petroleum coke is fed to the rod mill to be ground and mixed with water and recycled char (slag) from the IGCC pr ocess to create a slurry. The slurry is then pumped to the gasifier where it is mixed with oxygen from the air separation plant to create a syngas.

 The gasification process operates between 2,300  F and 2,700  F. This process creates syngas, slag, and flyash.Page 3

 The constituents in syngas vary de pending on the fuel blend. Currently, the syngas is about 30% hydrogen, 45% car bon monoxide, 15% carbon dioxide, 3% nitrogen, and about 1% sulfur.

 The slag and about 50% of the flyash gene rated collects in a wa ter pool located at the bottom of the gasification unit. The wet slag and flyash moves through the slag crusher onto the slag drag conveyor wh ere it is deposited onto a screen. The coarse material captured by the screen is collected and sold to the cement industry. Water and fines passing through the screen are considered “black water” which is pumped to the settler feed tank.

 Remaining flyash and syngas flow through a convective syngas cooler to a water scrubber (referred to as the “syngas scrubbe rs”) for the removal of particulates and hydrochloric acid (HCl) from the syngas. The scrubber blowdown, also referred to as “black water,” is pumped to the settler feed tank at about 400 gpm.

 Syngas is further cleaned in the carbonyl sulfide (COS) hydrolysis unit, which converts the COS to hydrogen sulfide (H 2 S). Following this unit, the gas is cooled through three small heat exchangers and sent to the acid gas removal system.

 In the acid gas removal system, the s yngas is scrubbed with methyl diethanol amine (MDEA), which captures the H 2 S in the syngas. The cleaned syngas is then heated, filtered with a 10-micron cartri dge filter, and sent to the combustor.

 The MDEA and H 2 S solution from the bottom of the scrubber is transferred to the MDEA stripper, which uses steam to release the H 2 S from the MDEA. The H 2 S and other noncondensibles gases are transfer red to the sulfuric acid plant. The MDEA is collected, cooled, and reused in the scrubber.

 The sulfuric acid plant produces abou t 200 tons per day of 93-98% acid.

Unit 1 Wastewater Treatment

 Diagrams of the wastewater flow and management associated with Unit 1 are

included as Attachment 4.

 Black water that collects in the settler f eed tank is pumped to one of two gravity settlers, where a flocculant and coagulan t are added. The overflow from the tanks is referred to as grey water and is stored in a conical tank. Most of the grey water is recycled to the syngas scrubbers, as shown in Attachment 2. Approximately 100 gpm is transferred to the brine concentration system.

 The underflow from the gravity settlers is recycled direc tly to the slurry preparation step.

 Grey water transferred to the brine co ncentrator is sent through a vapor compression cycle to evaporate the majority of the water. The brine concentrate, which contains about 30,000-40,000 ppm chlo rides, is transferred to a second evaporation step followed by a crystallizer to reclaim solid ammonium chloridePage 4

from the waste stream. The solids (16% moisture) are disposed off site. Approximately 15 tons of solids are produced each week.

 In the past, Polk experienced exceedances of the NPDES permit limit on selenium in discharges from the cooling water pond. Several forms of selenium were measured (Se-4, Se-6, and selenocyante). The source of the selenium responsible for the permit exceedances was found to be the neutralized weak acid return from the sulfuric acid plant. Selenocyanate has also been measured at low levels in leachate from the slag pile.

 Condensate from the brine concentrator is reused for pump s eals and instrument tap flushes. It contains le ss than 100 ppm chlorides.

Simple Cycle Unit Operations (Units 2 through 5)

 Units 2 and 3 are fueled by oil and natural gas, while units 4 and 5 are fueled only by natural gas.

 The air compressors are cleaned with a water/detergent solution every other year. The gas turbines are cleane d about every three years.

 Miscellaneous wastewaters, including c ontaminated precipitation, pump and seal leakage, and maintenance are managed in the oily water system.

 Water in the oily water system is treated through an API oil/water separator, followed by a dissolved air flotation ( DAF) unit, equalization basin, and sand filter (NPDES outfall I-004). Th e plant does not adjust th e pH in the equalization

basin or at outfall I-004 as it is not required by their NPDES permit. The treated water, including filter backwash, is th en discharged to the cooling pond.Page 5Table 1. Site Visit AttendeesNameOrganization (Representing)TelephoneE-mailKevin Young TECO Energy 813-228-4232 kayoung@tecoenergy.comStanley KrohTECO Energy813-228-4257 smkroh@tecoenergy.comPaul CarpinoneTECO Energy813-228-4858 plcarpinone@tecoenergy.comMike PerkinsTECO Energy813-228-1111 mrperkins@tecoenergy.comTemi LinjewileTECO Energy813-376-8823 tmlinjewile@tecoenergy.comJames P. Moore, Jr.TECO Energy813-228-1111 jpmoore@tecoenergy.comDonna HillUWAG205-257-5234 dbhill@southernco.comRon Jordan EPA/Office of Water 202-566-1003 jordan.ronald@epa.govDeb Bartram ERG (Contractor to EPA) 703-633-1669 deborah.bartram@erg.com