Tampa Electric

Integrated Gasification

Combined-Cycle Project

An Update

TOPICAL REPORT NUMBER 19 JULY 2000
TOPICAL REPORT NUMBER 19

A report on a project conducted jointly under

a cooperative agreement between:

The U.S. Department of Energy and

Tampa Electric Company

July 2000

The Tampa Electric

Integrated Gasification

Combined-Cycle Project

An Update
Cover image: The Polk Power Plant site as seen from across the lake in early evening. Photography

courtesy of Lee Schmoe, Bechtel Power Corporation.
The Tampa Electric

Integrated Gasification

Combined-Cycle Project

Executive Summary........................................................................................... 1

Background........................................................................................................ 2

Project Description ............................................................................................ 5

Power Plant Description .................................................................................... 7

Environmental Considerations .......................................................................... 9

Cost/Schedule .................................................................................................. 12

Project Objective ............................................................................................. 12

Plant Modifications/Improvements ................................................................. 12

Results ............................................................................................................. 14

Awards ............................................................................................................. 15

Commercial Applications ................................................................................ 15

Future Developments....................................................................................... 17

Market Potential .............................................................................................. 18

Conclusions ..................................................................................................... 19

Bibliography .................................................................................................... 20

Contacts for CCT Projects and U.S. DOE CCT Program ............................... 23

List of Acronyms and Abbreviations .............................................................. 24
1

IGCC Advantages

• A Clean Environment

• High Efficiency

• Low-Cost Electricity

• Potential for Low Capital Costs

• Repowering of Existing Plants

• Modularity

• Fuel Flexibility

• Phased Construction

• Low Water Use

• Low CO2 Emissions

• Public Acceptability

Executive Summary

The Clean Coal Technology (CCT)

Demonstration Program is a government

and industry co-funded effort to demonstrate a new generation of innovative coal

utilization processes in a series of “showcase” facilities built across the country.

These projects are carried out on a sufficiently large scale to prove technical feasibility and provide the information required

for additional commercial applications.

The goal of the CCT Program is to furnish the marketplace with a number of

advanced, more efficient coal-based technologies that meet strict environmental

standards. These technologies will mitigate the economic and environmental barriers that limit the use of coal.

To achieve this goal, beginning in

1985, a multi-phased effort consisting of

five separate solicitations has been administered by the U.S. Department of Energy’s

(DOE) National Energy Technology Laboratory (NETL), formerly the Federal Energy Technology Center. Projects selected

through these solicitations have demonstrated technology options with the potential to meet the needs of energy markets

while satisfying relevant environmental

requirements.

This report discusses the Tampa Electric Integrated Gasification CombinedCycle Project. In this project, the Texaco

coal gasification process is used to fuel a

gas combustion turbine generator, whose

exhaust is integrated with a heat recovery

steam generator and a steam turbine generator. Over 98% of sulfur contaminants

are removed. Sulfur is recovered as sulfuric acid which is sold, as is the slag

byproduct of gasification.

The project was conducted at Polk

Power Station, a greenfield site located

near Mulberry, Polk County, Florida.

The Tampa Electric CCT project has

successfully demonstrated the commercial application of Texaco coal gasification in conjunction with electric power

generation. Over 18,000 hours of operation have been accumulated. Net power

production meets the target goal of 250

MWe at a high stream factor and plant

availability. Carbon burnout exceeds

95%, and emissions of SO2, NOx and

particulates are well below the regulatory limits set for the Polk plant site.

The Polk facility is one of the cleanest

coal-based power plants in the world.
2

Background

The Clean Coal Technology (CCT)

Demonstration Program, sponsored by

the U.S. Department of Energy (DOE)

and administered by the National Energy

Technology Laboratory (NETL), has been

conducted since 1985 to develop innovative, environmentally friendly coal utilization processes for the world energy

marketplace.

The CCT Program, which is co-funded

by industry and government, involves a

series of commercial-scale demonstration

projects that provide data for design, construction, operation, and technical/economic evaluation of full-scale applications. The goal of the CCT Program is

to enhance the utilization of coal as a major energy source.

The CCT Program has also opened

a channel to policy-making bodies by

providing data from cutting-edge technologies to aid in formulating regulatory

decisions. DOE and the participants in

several CCT projects have provided the

Environmental Protection Agency (EPA)

with data to help establish emissions targets for nitrogen oxide (NOx) emissions

from coal-fired boilers subject to compliance under the 1990 Clean Air Act

Amendments (CAAA).

The Tampa Electric

Integrated Gasification

Combined-Cycle Project
3

Integrated Gasification

Combined-Cycle

Among the technologies being demonstrated in the CCT Program is Integrated

Gasification Combined-Cycle (IGCC).

IGCC is an innovative electric power generation process that combines modern coal

gasification with gas turbine and steam

power generation technologies. IGCC is

one of the most efficient and cleanest of

available technologies for coal-based electric power generation. This technology offers high system efficiencies, low costs,

and very low pollution levels.

IGCC power plants offer excellent environmental performance. Gasification

breaks down virtually any carbon-based

feedstock into its basic constituents, enabling

the separation of pollutants to produce clean

gas for efficient electricity generation. As a

result, atmospheric emissions of pollutants

are very low. Water use is lower than conventional coal-based generation because gas

turbine units require no cooling water, an especially important consideration in areas of

limited water resources. Due to their high

efficiency, less coal is used, causing IGCC

power plants to emit less carbon dioxide

(CO

2) to the atmosphere, thereby decreasing

concerns about climate change. Less coal use

also results in less ash requiring disposal.

Modularity and fuel flexibility are important attributes of IGCC power plants. The

combined-cycle unit can be operated on other

Aerial view of Polk Power Station
4

The sulfuric acid plant is located in the foreground and the gasifier and radiant syngas

cooler are in the tall midground structure

fuels, such as natural gas or fuel oil, before

the gasifier is constructed, to provide early

power. The size of gas turbine units can

be chosen to meet specific power requirements. Ability to operate on multiple fuels

permits continued operation of the gas turbine unit if the gasifier island is shut down

for maintenance or repairs, or if warranted

by fuel costs.

IGCC power plants use plentiful and

relatively inexpensive coal as their fuel. In

the United States there are several hundred

years of coal reserves, and use of coal

helps to reduce dependence on foreign oil.

Market forces, which are replacing

regulatory structures, are resulting in expanded IGCC applications. As a result of

both feedstock and product flexibility, traditional steam-powered electricity generation

using single feedstocks is being supplanted by more versatile integrated technologies.

Four IGCC demonstration projects are

included in the CCT Program: (1) the

Piñon Pine IGCC Power Project, (2) the

Wabash River Coal Gasification Repowering Project, (3) the Tampa Electric Integrated Gasification Combined-Cycle

Project, and (4) the Kentucky Pioneer

Energy Project. This Topical Report

describes the Tampa Project.
5

Tampa Electric Company Owner/operator

TECO Power Services Corporation Project management and commercialization

Texaco Development Corporation Licensor of gasification technology

General Electric Corporation Supplier of gas turbine/combinedcycle equipment

Bechtel Power Corporation Detailed engineering/construction

management services, procurement,

and startup

MAN Gutehoffnüngshutte AG Supplier of radiant syngas cooling system

L. & C. Steinmüller Gmbh Supplier of convective syngas cooling system

Air Products & Chemicals, Inc. Turnkey supplier for air separation unit

Monsanto Enviro-Chem Systems, Inc. Turnkey supplier for sulfuric acid plant

H.B. Zachry Company Power block construction

The Industrial Company Gasification area construction

Johnson Brothers Corporation Site development and civil contractor

Aqua-Chem, Inc. Supplier of brine concentration plant

Davenport Mammoet Transportation/erection of radiant

Heavy Transport syngas cooler

Major Participants

Project Description

The Tampa Electric Integrated Gasification Combined-Cycle Project was selected

by DOE in December 1989 as a CCT Program Round III demonstration project.

Construction was started in October 1994

and operation began in September 1996.

The project demonstrates use of the

Texaco coal gasification process to fuel

a gas combustion turbine generator, whose

exhaust is integrated with a heat recovery

steam generator (HRSG) and steam turbine

generator. Over 98% of sulfur contaminants are removed. Sulfur is recovered as

sulfuric acid which is sold, as is the slag

byproduct of gasification. The greenfield

site is located near Lakeland, Polk County,

Florida.

The combustion turbine is an advanced

General Electric gas turbine unit that produces 192 MWe (gross). The steam turbine

produces an additional 121 MWe (gross).

With parasitic power consuming 63 MWe,

total net power output is 250 MWe.

The demonstration also includes integration of nitrogen from the air separation

plant with the gas turbine. Steam produced

at various gas cooling stages is integrated

with the HRSG and other process needs.

Project Participant

The Participant is Tampa Electric Company (TEC), headquartered in Tampa,

Florida. Its service territory includes the

city of Tampa and a 2000-square mile area

in west-central Florida, primarily in and

around Tampa. TEC, an investor-owned

electric utility serving over 500,000 customers, has about 3650 MWe of generating

capacity, of which about 97% is coal-fired.

TEC is the principal wholly-owned subsidiary of TECO Energy, Inc., an energy related holding company heavily involved

in coal mining, transportation, and power

generation.

TECO Power Services Corporation

(TPS), another subsidiary of TECO Energy, operates two power plants firing

natural gas: a 295-MWe combined-cycle

plant in Hardee County, Florida and a 78-

MWe plant in Guatemala. In addition, TPS

has several other projects at various stages

of development.
6

Project Subcontractors

Other participants in the CCT project

are major technology suppliers, including

Texaco Development Company, the licensor of the coal gasification process; General Electric Corporation, the supplier of

the combined-cycle technology; Air Products and Chemicals, Inc., supplier of the air

separation unit; Monsanto Enviro-Chem

Systems, Inc., supplier of the sulfuric acid

plant; TPS, project manager and marketer;

and Bechtel Power Corporation, who provided detailed engineering and construction management services.

Site Description

The demonstration unit is Unit 1 of the

Polk Power Plant, a new facility built in

1996 and located near Mulberry in south

central Polk County, Florida. The 4300-

acre site is about 45 miles southeast of

Tampa and 17 miles south of Lakeland,

in the heart of central Florida’s phosphate

mining region.

The Polk site is on a tract of land that

had been previously mined for phosphate

rock, and has been redeveloped and revegetated by TEC for this project.

The area is predominantly rural. Polk

County is an important citrus-raising and

phosphate mining center, each being important Florida industries.

About one-third of the site is used for

power generation facilities. Another third,

about 1500 acres, is used to enhance the

environment by creation of public fishing

lakes for the Florida Fish and Game Commission. This area was converted from

phosphate mining spoils to wetlands and

uplands, thereby providing habitat for native plants and animals, and was transferred to the Commission in 1997. The

final third of the site is used primarily for

access and to provide a visual buffer.

The site contains an 850-acre cooling

reservoir. State Highway 37 crosses the

site about one mile from the IGCC power

plant.

Makeup water for the power plant is

provided from on-site wells. All process

water is recycled.

Coal Supply

Coal is delivered to the site by truck

from a transloading facility at TEC’s Big

Bend Station in Apollo Beach, Florida.

Coals tested include Illinois No. 6, Pittsburgh No. 8, Kentucky No. 9, and Kentucky No. 11, all bituminous coals having

a sulfur content ranging from 2.5-3.5%.

New U.S. Generating Capacity Forecast

1998–2020

Source: U.S. Energy Information Administration, 1999

140

120

100

80

60

40

20

0

Combustion Renewables

Turbines

Combined

Cycle

Fossil

Steam

Capacity, GWe

Includes non-utility generators and cogenerators
7

Process

flow diagram

Power Plant

Description

The Tampa CCT project demonstrates

advanced IGCC technology using Texaco’s

commercially available oxygen-blown, entrained-flow gasifier, integrated with a combined-cycle turbine system for power

generation.

The facility processes approximately

2,200 tons/day of coal in a single Texaco

gasifier. Once on site, the coal is ground

and slurried using recycled process water

and makeup water. The slurry contains

60-70% solids.

Coal is partially oxidized in the gasifier

with 95% pure oxygen from the air separation unit to produce a high temperature,

high pressure, medium-Btu synthesis gas

(syngas) with a heat content of about

267 Btu per standard cubic foot. The

gasifier achieves about 95% carbon conversion per pass. Molten ash flows from

the bottom of the gasifier into a waterfilled sump, where it solidifies into

a marketable slag byproduct. The slag,

which is nonleachable, is sold for use

in blasting grit, roofing tiles, and construction products.

The syngas is cooled in a high-temperature radiant heat exchanger, generating high pressure steam. The cooled gas

is washed with water for particulate removal, followed by a hydrolysis reactor

where carbonyl sulfide (COS) is converted to hydrogen sulfide (H2S). After

additional cooling, the raw syngas is sent

to a conventional acid gas removal unit,

where H2S is absorbed by scrubbing with

an amine solvent. H2S is removed from

Steam

Coal Handling

and Slurry

Preparation

COS

Hydrolysis

Steam

Combustor

N2 from Air

Separation Plant

Hot Exhaust Gas

Flue

Gas to

Stack

Gas Turbine

Steam Turbine

Steam

Steam

Generator

Generator

Sulfuric Acid

Plant

Raw Syngas

Raw Syngas

Syngas

Acid

Gas

Removal

Amine

Scrubbing

Clean Syngas

Product

Gas

Cooler

Heat Recovery

Steam Generator

Sulfuric

Acid

Air

Slag to

Disposal

Radiant

Syngas

Cooler

Coal

Slurry

Feed

Water

“Black Water”

Recycled

Oxygen from Air

Separation Plant

High

Pressure

Steam

Texaco

Gasifier

Syngas
8

IGCC Inputs and Outputs

Inputs Quantity, tons/day

Coal 2,200

Oxygen 2,171

Slurry water (recycled) 972

Nitrogen to gas turbine 5,600

Solids Output

Slag/fines from dewatering pit 342

Dry solids from brine concentrator 3.1

98% Sulfuric Acid 240

Net Electrical Output 250 MWe

Selected Milestones

• Initial roll of the steam turbine:

June 1996

• Sulfuric acid plant and gasifier

completion: June 1996

• Start of operational test

program: October 1996

• First continuous run > 50 days

for combustion turbine:

September 1998

• Produced > 1.2 million MWh

in 1998

• 94% availability for the

combined-cycle system

achieved by end of 1999

• > 18,000 hrs. of operation by

the end of 1999

• First petroleum coke burned:

1st quarter 2000

the amine by steam stripping and sent to

the sulfuric acid plant.

As originally envisioned, the overall

process scheme was to have incorporated

hot gas cleanup on a portion of the raw

syngas stream. After some initial test work,

support for this option was discontinued.

The cleaned syngas is sent to the General Electric model MS 7001FA gas combustion turbine. Nitrogen from the air

separation unit (at 98% purity) is mixed

with the syngas at the combustor inlet.

Nitrogen addition has important benefits

to the power plant: (1) the increased mass

flow through the gas turbine produces

more power than without the nitrogen;

(2) the overall efficiency of the system is

enhanced; (3) NOx emissions are reduced;

and (4) nitrogen injection is a viable alternative to steam. The use of nitrogen that

would otherwise be vented represents

a novel approach in oxygen-blown gasification technology.

Hot exhaust from the gas turbine

passes through the HRSG, where three

pressure levels of steam are produced.

The majority of the steam is at high pressure and, with high pressure steam produced in the gasification stage, drives

the reheat steam turbine generator.

A 220-kV, five-mile transmission

line connects the Polk Power Station

to the TEC grid.

The sulfuric acid plant uses oxygen

and a catalytic reactor to convert the H2S

from the gas cleanup system to sulfuric

acid (H2SO4), which is sold to the local

phosphate mining industry. H2SO4 production is about 240 tons/day.

A brine concentration unit processes

“grey” water discharged from the gas

cleanup systems, recovering a reusable

water stream for slurry preparation and

a land-fillable solid waste stream. There

is no liquid effluent.

Gaseous emissions are controlled to

very low levels. SO2 emissions are below 0.15 lb/million Btu and NOx emissions are below 0.27 lb/million Btu. The

target emissions for the Tampa Electric

project are 0.21 lb/million Btu for SO2

and 0.27 lb/million Btu for NOx. Emissions of particulates are consistently below 17 lb/hr, the permit limit. Thus, the

plant performance exceeds project goals.
9

Polk Site before (above) and after (below) construction

Environmental

Considerations

As indicated above, the Tampa IGCC

Project has very low pollution impacts.

Environmental considerations have been

a major driving force from the inception

of the project. The site was selected by

an independent Community Siting Task

Force, commissioned by TEC. Members

included environmentalists, educators,

economists, and community leaders.

Economic factors were also considered.

The Task Force evaluated 35 sites in six

counties and recommended three in southwestern Polk County that had previously

been mined for phosphate.

EPA, the lead federal agency, issued

the final Environmental Impact Statement

for this project in June 1994. Favorable

records of decision were issued by EPA,

the U.S. Army Corps of Engineers, and

DOE. Some of the inputs for this comprehensive document were provided by TEC

and its environmental consultants.

All federal, state, and local environmental permits were obtained. An Environmental Monitoring Plan was developed by TEC

that gives details of the performance monitoring of environmental control equipment,

stack emissions, and the surrounding area.
10

Process Description

Coal Gasification

Texaco coal gasification technology uses a single-stage, downwardfiring, entrained-flow coal reactor

fed with a coal/water slurry (60-70%

water) and 95% pure oxygen. The

coal reacts with steam and oxygen

at a temperature of 2400-2600 °F

to produce raw fuel gas and molten

ash. The hot gas flows downward

into a radiant gas cooler, where

high pressure steam is produced.

The syngas passes over the surface

of a pool of water at the bottom of

the syngas cooler and exits the vessel. The slag drops into the water

pool and is fed to the lockhopper

from the syngas cooler sump.

The radiant gas cooler is about

16 feet in diameter and 100 feet

long, and weighs about 900 tons.

The “black” water flowing out with

the slag is separated and recycled

after processing in the dewatering

system.

The raw syngas exiting the radiant syngas cooler is sent to parallel convective coolers, where it is

cooled to below 800°F and additional high pressure steam is produced.

Gas Cleanup

Particulate matter and hydrogen

chloride (HCl) are removed from the

syngas by scrubbing with water. The

scrubber bottoms are routed to the

“black” water handling system where

the solids are separated. The effluent is concentrated and crystallized

as a solid that is shipped off-site

either for reuse or for disposal in

a permitted landfill. The separated

water is recycled for slurrying coal

feed.

COS Hydrolysis

One compound produced in the

gasification reactor is carbonyl sulfide (COS), which cannot be removed in the downstream amine

scrubbing unit. If not removed from

the syngas stream, COS is converted to SO2, which must be minimized in the plant stack gas. The

COS problem is accentuated when

higher sulfur coals are fed to the

gasifier.

To avoid this problem, Polk plant

staff designed and installed a hydrolysis unit, a cylindrical vessel

in which COS is reacted with water

in the presence of a catalyst to form

CO2 and H2S. Polk personnel selected the catalyst based on testing

performed on the plant syngas. Six

catalysts were tested, of which two

proved satisfactory and one was

chosen for this service. Preliminary

operating results indicate negligible

catalyst degradation. Long-term

operation will be required to fully

evaluate the COS hydrolysis step.

Acid Gas Removal

The COS-free syngas flows to the

amine absorber, where the H2S and

some of the CO2 is absorbed. The rich

amine is stripped of acid gas in the

stripper. The amine is recycled and

the separated acid gas is routed to

the sulfuric acid plant.

Sulfuric Acid Plant

In the sulfuric acid plant, the sulfurcontaining gases from the gas cleanup

system are converted to 98% H2SO4

for sale to the local Florida fertilizer

industry. The H2S is converted to SO2

by combustion with air. Medium pressure steam is generated from the combustion products. The SO2 is oxidized

over a vanadium pentoxide catalyst,

forming SO3. The SO3 is scrubbed

with weak sulfuric acid to make 98%

H2SO4. The concentration of SO2 and

SO3 remaining in the gas stream is

low enough to permit direct discharge

to the atmosphere through a 200-ft

stack.

C (coal) + O2 ---> CO2 + Heat

C (coal) + H2O (steam) ---> CO + H2

Simplified Gasification Chemistry
11

Power Block

The gas turbine is a General Electric model MS 7001FA, designed for

low NOx emissions when fired with

syngas and with low-sulfur fuel oil that

is used for startup and backup. Rated

output from the hydrogen-cooled generator when syngas is fired is 192

MWe. The gas turbine uses an advanced design that has been proven

in a utility environment.

Nitrogen is used as a syngas

diluent to reduce NOx formation

and to increase mass flow, resulting

in higher power output from the gas

turbine.

The heat recovery steam generator

(HRSG) is a three-pressure design

with natural circulation and reheat.

The exhaust gas leaving the HRSG

is vented to the atmosphere via

a 150-ft stack. The steam from the

HRSG flows to a steam turbine, which

is a double flow reheat unit with lowpressure extraction. Nominal steam

inlet conditions are 1450 psig and

1000°F with 1000°F reheat temperature. Generator output during normal

operation is 121 MWe.

Total power production is 192 MWe

from the gas turbine and 121 MWe

from the steam turbine, giving a total

of 313 MWe. With parasitic power of

63 MWe, total net power output is 250

MWe.

Air Separation Unit

The conventional air separation unit

provides 95% pure oxygen for the gasifier operation, and warmed compressed nitrogen for the gas turbine.

Low-pressure 95% oxygen is also supplied to the sulfuric acid plant.

A single Texaco gasifier processes 2,200 tons per day of coal to produce

a raw syngas and molten slag. The gas flows downward into the radiant

syngas cooler where it is partly cooled and high-pressure steam for power

generation is produced. Slag is collected in a water pool at the bottom of

the radiant syngas cooler and removed.

Radiant

Syngas

Cooler

Coal

Slurry

Feed

Water

“Black Water” Recycled

Oxygen from Air

Separation Plant

High

Pressure

Steam

Texaco

Gasifier

Syngas

Slag to

Disposal
12

Cost/Schedule

The total cost of the Tampa Electric

IGCC Project is $303 million, of which

the Participant has provided $152 million (51%) and DOE has provided $151

million (49%). The cooperative agreement between TEC and DOE was

signed in March 1991. Construction

started in August 1994, and operation

began in September 1996. A four-year

demonstration program is in progress,

with completion expected by October

2000.

The total project cost includes the cost

of operating the unit throughout the demonstration peroid as well as experimental

work on hot gas cleanup. The investment

for a commercial unit would be significantly lower than that of the Tampa

project.

Gas turbine, model MS 7001F, during manufacture

 Pollutant Allowed Emissions,

lb/hr

SO2 357

NOx 223

CO 98

VOC 3

PM/PM-10 17

Allowed Stack Emissions

Project Objective

The project objective is to demonstrate IGCC technology in a greenfield

commercial electric utility application

at the 250-MWe scale using a Texaco

gasifier with full heat recovery, conventional cold-gas cleanup, and an advanced gas turbine with nitrogen

injection for power augmentation

and NOx control.

Plant Modifications/

Improvements

Several modifications to the original

design and procedures were required

to achieve the high availability that has

been demonstrated. Soon after initial

startup, ash plugging caused failure

of some exchangers in the high-temperature heat recovery system. This

led to serious damage to the combustion turbine. The exchangers were

removed in 1997, and compensating

adjustments were made in the rest of

the heat recovery system. Additional

particulate removal was provided to

protect the turbine.

Pluggage in another bank of exchangers in the high-temperature heat

recovery system was arrested by a design modification in 1999.

In late 1997, hot restart procedures

were implemented. These eliminated

the need to change burners and reheat

the gasifier every time it shut down,

reducing gasifier restart time by over

18 hours.
13

Initially, there were problems with the

gasifier which is 50% larger than any previous Texaco gasifier. Carbon conversion

in this larger gasifier was lower than expected, and refractory life has been identified as a significant issue. Liner replacement

is expensive and requires considerable

down time. To achieve the target life of

two years, the gasifier is being operated at

a lower temperature than design, which in

turn results in a further decrease in carbon

conversion efficiency. This caused load restrictions due to capacity limitations in the

fines handling system. A slag crusher and a

duplicate fines handling system installed in

1998 solved this problem.

Thermocouple replacement in the gasifier also presents a problem. Replacement

is relatively expensive. Thermocouple failure by shearing is attributed to expansion

of dissimilar materials.

In early 1998, revised operating procedures were developed to handle high shell

temperatures in the dome of the radiant

syngas cooler. This problem had caused

two extended outages.

Numerous short forced outages occurred

in 1997 and 1998 due to erosion and corrosion in the process water and coal/water

slurry piping systems, pumps, and valves.

Various changes have virtually eliminated

these problems, and no such outages occurred in 1999. Some of the corrective

actions taken to solve operating and maintenance problems in this project have resulted in patent applications.

Gas Turbine 192 MWe

Steam Turbine 121 MWe

Gross 313 MWe

Auxiliaries Power Use 63 MWe

Net Power Output 250 MWe

Power Output

The Texaco gasifier is in the largest structure, which also contains the radiant syngas

cooler. The hot gas cleanup system is installed in the smaller of the two large structures.

In the foreground is the air separation unit.
14

The sulfuric acid plant is in the foreground and the combined-cycle unit is in the

background. The large black object (left center) is the heat recovery steam generator

Gasifier Run Summary

7/96 First production of syngas

8/96 Achieved steady state in process water system

8/96 First utilization of low-temperature gas cooling system

9/96 Achieved 100% gasifier load, first syngas to gas turbine,

and first production of brine crystals

9/96 First integration of steam drums

10/96 First run >100 hours, full load gas turbine and combined-cycle

operation on syngas, and first production of sulfuric acid

1/97 First continuous 30-day run

Start Date Major Accomplishments

Results

Polk Power Station has operated over

18,000 hours, generating more than 4.8

million MWh of electricity through 1999.

For the last six months of 1999, the gasifier had an 83.5% on-stream factor, and

the combined-cycle availability was 94%.

The gasifier and combustion turbine continuous operation records are 46 and 52

days, respectively.

Environmental performance has been

excellent. The overall heat rate is 9350

Btu/kWh (36.5% efficiency, higher heating

value basis). The efficiency is somewhat

lower than design because of removal of

the high temperature exchangers and lower

than excepted carbon conversion discussed

above, and a compressor failure in the

brine concentration unit which necessitates

its operation as a single effect evaporator.

In the second half of 2000, a slag recovery

system will be commissioned to recover

and utilize the unconverted carbon, and the

brine concentration unit will be restored

to its original more efficient vapor compression cycle. Ways are being evaluated

to utilize the heat available as a result of

removing the high temperature exchangers.

Together, these projects are expected to increase the efficiency to 38% (9000 Btu/

kWh), consistent with the original design

value.

Ten coals and blends were tested in the

3 years of operation to date to determine

the impact of feedstock properties on system performance. These coals included

Kentucky No. 9, Kentucky No. 11, two

Illinois No. 6 coals, and three Pittsburgh

No. 8 coals. The performance criteria

were: (1) feasibility of processing into

a high concentration slurry, (2) carbon

conversion, (3) aggressiveness of the slag

to the gasifier’s refractory liner, and (4)

tendency toward fouling of the syngas
15

Dawn arrives over the reclaimed wetlands surrounding the Tampa Electric Integrated

Gasification Combined-Cycle Project

Five Powerplant Awards Presented to CCT

Projects by Power Magazine

• Tampa Electric Integrated Gasification Combined-Cycle Project (Tampa

Electric Company) - 1997

• Wabash River Coal Gasification Repowering Project (Cinergy

Corporation/PSI Energy Inc.) - 1996

• Demonstration of Innovative Applications of Technology for the CT-121

FGD Process (Southern Company Services, Inc.) - 1994

• Advanced Flue Gas Desulfurization Demonstration Project (Pure Air on

the Lake, L.P.) - 1993

• Tidd PFBC Demonstration Project (The Ohio Power Company) - 1991

coolers. All of the coals were found to be

suitable with some design modifications.

The unit is currently running Kentucky

No. 9 coal. Testing of lower cost petroleum coke blends is in progress.

Awards

The project was presented the 1997

Powerplant Award by Power magazine.

In 1996, the project received the Association of Builders and Contractors Award

for construction quality. Several awards

were presented for using an innovative

siting process, including the 1993 Ecological Society of America Corporate

Award and the 1991 Florida Audubon

Society Corporate Award.

Commercial

Applications

In addition to generating power, the

IGCC process can also be modified to

produce value-added chemicals or transportation fuels from coal by chemical processing of the gas produced, as opposed

to using the gas to drive a combustion turbine. It may very well be that the nearterm market niche for IGCC lies not only

in the production of electricity, but also in

the generation of multiple products, where

electricity, steam, and chemicals are economically bundled as products from a fully

integrated complex. Such plants are envisioned in forward-thinking concepts such

as the DOE’s “Vision 21” initiative.

As a result of the Tampa demonstration project, Texaco-based IGCC can

be considered commercially and environmentally suitable for electric power

generation utilizing a wide range of feedstocks. Sulfur capture for the project is
16

Coal Gasification

Coal gasification has been

used for many years. Primitive

coal gasification provided town

gas worldwide more than 100

years ago, and a gasification

industry produced coal-based

transportation fuels for Germany

in World War II.

Today, coal gasification is

seeing increasing use. In the

U.S., a Texaco gasifier is utilized

in commercial operation at the

Tennessee Eastman chemical

plant in Kingsport, Tennessee

to produce synthesis gas for production of methanol. The Dakota

Gasification plant in North Dakota

produces substitute natural gas

and chemicals based on an advanced World War II gasification

technology.

Overseas, a major chemical

and transportation fuel industry

exists in The Republic of South

Africa, mostly based upon advancements of World War II gasification technologies. An IGCC

power plant is in operation in The

Netherlands. There are several

German gasifiers that are commercially available. Texaco gasifiers are in commercial operation,

or planned operation, in the

People’s Republic of China

and other nations.

Advanced gasification and IGCC

technology development began in

the U.S. in the 1960s, the stimuli being the desire for (1) development of

coal-based replacements for natural

gas and oil due to shortages and

price increases; and (2) more efficient, clean coal-based power

plants. Modern IGCC technology is

a response of U.S. government and

industry to these needs. Such systems use advanced pressurized coal

gasifiers to produce a fuel for gas

turbine-based electric power generation; the hot-gas turbine exhaust

produces steam to generate additional electricity.

The first commercial scale use

of a gasifier in a U.S. IGCC project

was the Cool Water Project in California, which was based upon the

Texaco coal gasification technology.

The Cool Water Project, which received major support from the U.S.

Synthetic Fuels Corporation, Southern California Edison Company,

EPRI (formerly the Electric Power

Research Institute), and others, was

instrumental in proving the feasibility

of IGCC, including their exceptional

environmental performance.

Gas turbines for power generation

have been one of the consequences

of jet aircraft engine development.

Initially utilized for peaking purposes

by utilities, their reliability, efficiency

and output have improved to the extent that they now also provide intermediate and baseload electric power.

It is projected that gas turbines and

IGCCs will contribute significantly to

future increases in power generation.

Today’s IGCC is efficient because

of major improvements that have

taken place in coal gasification and

gas turbine technologies, and a high

degree of system integration that

efficiently recovers and uses waste

heat.

Gas cleanup in an IGCC power

plant is relatively inexpensive compared with flue gas cleanup in conventional coal-fired steam power

plants. Smaller equipment is required because a much smaller volume of gas is cleaned. This results

from the fact that contaminants are

removed from the pressurized fuel

gas before combustion. In contrast,

the volume of flue gas from a coalsteam power plant is 40-60 times

greater because the flue gas is

cleaned at atmospheric pressure.

Atmospheric emissions are very

low due to proven technologies for

highly effective removal of sulfur and

other contaminants from the syngas.

Advancements being demonstrated

in the CCT program are expected

to result in still better efficiencies.
17

Typical Coal Analysis

(Pittsburgh No. 8 Seam)

Ultimate Analysis, As-Received, wt%

Moisture 4.74

Carbon 73.76

Hydrogen 4.72

Nitrogen 1.39

Chlorine 0.10

Sulfur 2.45

Ash 7.88

Oxygen 4.96

Total 100.0

Higher Heating Value 13,290 Btu/lb

Polk Power Station control room

greater than 98%, while NOx emissions

are reduced by over 90% compared with

those of a conventional pulverized coalfired power plant.

The integration and control approaches

utilized at Polk and many of the other lessons learned can also be applied in IGCC

Projects using different gasification technologies.

TECO Energy is actively working with

Texaco to commercialize the technology in

the U.S. and overseas as well.

Future

Developments

Work is in progress on two equipment

modifications, both of which have efficiency improvement as a major objective.

The first is to commission the slag handling system that separates the slag into

its main constituents, a by-product for

sale and a fuel for recycle. The second

is to upgrade the brine concentration system by converting it to a more efficient

vapor compression cycle.

The achievements and knowledge

gained from the Tampa Electric IGCC

project demonstration are expected to

benefit future users of this technology.

Evaluation of advanced features of the

Project will determine their viability for

future commercial applications. Future

offerings of the technology are anticipated

to have lower cost and exhibit improved

performance.

DOE believes that future IGCC power

plants, based on mature and improved

technology, will cost in the range of

$900-1250/kW (1999 basis) depending

on the degree to which existing equipment and infrastructure can be utilized.

Heat rate ultimately is expected to be in

the range of 7000-7500 Btu/kWh (46-49%

efficiency, higher heating value basis).
18

Composition of

Cleaned Syngas

Constituent Volume %

Carbon monoxide 42.7

Hydrogen 38.3

Carbon dioxide 14.4

Methane 0.1

Water 0.3

Nitrogen 3.3

Argon 0.9

Hydrogen sulfide 200 ppmv

Carbonyl sulfide 10 ppmv

Ammonia 0.0 ppmv

Cumulative worldwide gasification capacity and growth

1970 1974 1978 1982 1986 1990 1994 1998 2002

MWth Syngas

10,000

20,000

30,000

40,000

50,000

60,000

Planned

Existing

Market Potential

A number of factors are converging

that contribute to the growth of gasification-based power generation worldwide.

These factors include advances in gasification technology; improved efficiency and

reduced cost of gas turbines; fuel flexibility, permitting use of lower quality, lower

cost feedstocks; and deregulation of the

power industry. This growth adds to an

already important role gasification technologies have played in the production

of chemicals and transportation fuels.

Currently there are over 160 existing

or planned gasification projects worldwide,

representing a total of more than 410

gasifiers with a combined syngas output

of over 60,000 MWth. Conversion of all

of this syngas to electricity by means

of IGCC equates to over 33,000 MWe

of power equivalent. Of the total worldwide

capacity, gasification facilities currently

operating or under construction account

for about 130 plants with a total capacity

of about 43,000 MWth. The current annual

growth in gasification is about 3,000 MWth

of syngas, or about 7% of the total operating

worldwide capacity. Planned projects indicate that this growth will likely continue

through the next five years, mostly in

Western Europe, Asia, Australia, and

North America.

At present, the use of syngas to produce

chemicals is the dominant market for IGCC

technology worldwide. Power generation is

gaining quickly, and represents most of the

recent and planned capacity additions. Much

of this growth is in gasification-based power

generation at oil refineries.
19

GE frame 7FA combustion turbine

(left background) and its generator

(right center) and clean gas filter

(lower left foreground). The clean

syngas filter prevents pipe scale

and any coal ash from damaging

the combustion turbine. The filter

was installed in response to two

turbine failures from coal ash and

pipe scale in 1997, and has proven

its worth.

Conclusions

The Tampa Electric IGCC project

conducted at Polk Power Station has successfully demonstrated the commercial

application of Texaco coal gasification

in conjunction with electric power generation. Power production meets the

target goal of 250 MWe at a high stream

factor and plant availability. Carbon burnout exceeds 95%, and emissions of SO2,

NOx and particulates are well below the

regulatory limits set for the Polk plant

site.

Along with other IGCC demonstrations in the CCT Program, the Polk Plant

is one of the cleanest coal-based power

generation facilities in the world.

Throughout the United States there are

more than 95,000 MWe of existing coal-fired

utility boilers over 30 years old. Many of these

plants are without air pollution controls, and

are candidates for repowering with IGCC

technology. IGCC technology is projected to

be a major candidate for both repowering and

new power generating capacity. The Tampa

Electric CCT Project is an example of a new

power plant using IGCC technology.

IGCCs offer the advantages of modularity,

rapid and staged on-line generation capability,

high efficiency, flexibility, environmental controllability, and reduced land and natural resource needs. For these reasons, IGCCs are a

strong contender for new electric power generation. Commercial offerings of IGCC technology will be based on a nominal 300-MWe

train, which is ideally suited to utility-scale

power production.
20

Bibliography

S.D. Jenkins, “Status of Tampa Electric

Company IGCC Project,” First Annual

Clean Coal Technology Conference

(Cleveland OH), November 1992.

D.E. Pless, “Tampa Electric Company:

Integrated Gasification Combined-Cycle

System,” Second Annual Clean Coal Technology Conference (Atlanta GA), September 1993.

C.R. Black, “Polk Status Update,” Twelfth

EPRI Conference on Coal Gasification

Power Plants (San Francisco CA), October

1993.

S.D. Jenkins, “Polk Status Update,” Economics of Emerging Clean Coal Technologies III, February 1994.

U.S. Environmental Protection Agency,

“Final Environmental Impact Statement,

Tampa Electric Company-Polk Power Station,” EPA 904/9-94-002(b), June 1994.

Tampa Electric Company, “Tampa Electric

Company Polk Power Station Unit No. 1,”

Preliminary Public Design Report, June

1994.

D.E. Pless, “Polk Status Update,” Third

Annual Clean Coal Technology Conference (Chicago IL), September 1994.

S.D. Jenkins, “Polk Power Station Syngas

Cooling System,” Eleventh Worldwide

Texaco Gasification Licensee Symposium

(White Plains NY), October 1994.

P.A. Pritchard and G.J. Starheim, “Turbine

Developments for IGCC Applications, Status Update,” Thirteenth EPRI Conference

on Coal Gasification Power Plants (San

Francisco CA), October 1994.

D.E. Pless, “Status Update, Polk Power

Station” Fourth Annual Clean Coal Technology Conference (Denver CO), September 1995.

S.D. Jenkins, “Tampa Electric Company

Polk Power Station IGCC Project,” Twelfth

Annual International Pittsburgh Coal Conference (Pittsburgh PA), September 1995.

C.R. Black, “Tampa Electric Company’s

Polk Power Station Construction Update,”

EPRI Conference on New Power Generation Technology (San Francisco CA), October 1995.

Aerial view of Tampa skyline
21

“Startup of Large-Scale Projects Casts

Spotlight on IGCC,” Power, June 1996.

“Compare Air-Blown to Oxygen-Blown

Gasification,” Power, June 1996.

Topical Report No. 6, “The Tampa Electric

Integrated Gasification Combined-Cycle

Project,” U.S. DOE, October 1996.

“Clean Coal Technology Breakthroughs

are Expected to Keep Coal a Viable Option,” Power Engineering, May 1997.

“1997 Powerplant Award - Polk Power

Station,” Power, June 1997.

“IGCC Technology Offers Fuel Diversity,

Coproduction for Competitive Generation,” Power Engineering, September

1997.

“IGCC Offers Diversity for Competitive

Generation,” Power Engineering, November 1997.

J.E. McDaniel and C.A. Shelnut, “Tampa

Electric Company Polk Power Station

IGCC Project -- Project Status,” Sixth

Clean Coal Technology Conference

(Reno NV), May 1998.

“Preparing for the Millennium,” Power

Engineering, November 1998.

J.E. McDaniel and C.A. Shelnut, “Tampa

Electric Company Polk Power Station

IGCC Project -- Project Status,” Seventh

Clean Coal Technology Conference

(Knoxville TN), June 1999.

J.E. McDaniel and C.A. Shelnut, “Tampa

Electric Company Polk Power Station

IGCC Project -- Project Status,” 1999

Gasification Technologies Conference

(San Francisco CA), October 1999.

“IGCC Gathers Pace,” Power Engineering,

November 1999.

U.S. Department of Energy, Energy Information Administration, “Annual Energy

Outlook 2000 with Projections to 2020,”

December 1999.

“Cleaning Up on Economics,” Power

Engineering, December 1999.

U.S. Department of Energy and the Gasification Technologies Council, “Gasification–Worldwide Use and Acceptance,”

January 2000

“Merchant Power Projects Push for Competitive Edge,” Power, pp. 32-39, January/

February 2000.

U.S. Department of Energy, Clean Coal

Technology Demonstration Program–

Program Update, April 2000.
22

The Clean Coal Technology (CCT)

Program of the U.S. Department of Energy (DOE), a model of government

and industry cooperation, supports

DOE’s mission to foster a secure and

reliable energy supply system in the

United States that is environmentally

and economically sustainable. The

CCT Program represents an investment of over $5 billion in advanced

coal-based technology, with industry

and state governments providing a

significant share —66% —of the funding. With 26 of the 38 projects having

completed operations, the CCT Program has resulted in clean coal technologies that are capable of meeting

existing and emerging environmental

regulations and competing in a deregulated electric power marketplace.

The CCT Program provides a portfolio of process options that will enable continued use of the United

States’ huge economically recoverable coal reserves (over 270 years

at current consumption rates) to meet

the nation’s energy needs economically and in an environmentally sound

manner.

As the new millennium begins,

many of the clean coal technologies

have reached commercial status. Industry stands ready to employ them

both domestically and internationally

to respond to the energy and environmental demands of the 21st century.

For existing power plants, there are

cost-effective environmental control

devices to minimize emissions of sulfur dioxide (SO2), nitrogen oxides

(NOx), and particulate matter (PM).

The CCT Program has taken a pollution prevention approach as well,

providing technologies that remove

pollutants or their precursors from

coal before combustion.

The Clean Coal Technology Program

Also ready is a new generation

of technologies that can produce electricity and other commodities, such as

steam and synthesis gas, at high efficiencies consistent with concerns

about global climate change.

Additionally, new technologies

have been introduced into major

coal-using industries, such as steel

production, to enhance environmental performance. Thanks in part to

the CCT Program, coal—abundant,

secure, and economical throughout

much of the world—can continue in

its role as a key component in supplying U.S. and world energy needs.

The CCT Program also has global

importance in providing clean and

efficient coal-based technologies

to a burgeoning energy market in

developing countries. World energy

consumption is expected to increase

63% by 2020, and coal, the predominant indigenous fuel in much of the

world, will be the fuel of choice for

electricity production. CCT processes offer a cost-effective means

to mitigate potential environmental

problems associated with this unprecedented energy growth.

Most of the CCT demonstrations

have been conducted at commercial

scale, in actual user environments,

and under circumstances typical of

commercial operations. Each project

addresses one of the following four

market sectors:

• Advanced electric power

generation

• Environmental control devices

• Coal processing for clean fuels

• Industrial applications

The project described in this Topical Report was developed under the

category of Advanced Electric Power

Generation.

Installation of radiant syngas cooler
23

Robert C. Porter

Director, Office of Communication

U.S. Department of Energy, FE-5

1000 Independence Ave SW

Washington DC 20585

(202) 586-6503

(202) 586-5146 fax

robert.porter@hq.doe.gov

Otis Mills

Public Information Office

U.S. Department of Energy

National Energy Technology

Laboratory

P.O. Box 10940

Pittsburgh PA 15236-0940

(412) 386-5890

(412) 386-6195 fax

otis.mills@netl.doe.gov

Participant Contact

Mark Hornick

General Manager - Polk Power Station

Tampa Electric Company

P.O. Box 111

Tampa FL 33601-0111

(813) 228-1111 x 39988

(863) 428-5927 fax

mjhornick@tecoenergy.com

U.S. Department of Energy Contacts

Victor Der

Director, Office of Power Systems

U.S. Department of Energy, FE-24

Germantown MD 20874-1290

(301) 903-2700

(301) 903-2713 fax

victor.der@hq.doe.gov

James U. Watts

Project Manager

National Energy Technology

Laboratory

P.O. Box 10940

Pittsburgh PA 15236-0940

(412) 386-5991

(412) 386-4775 fax

jim.watts@netl.doe.gov

Contacts for CCT Projects

and U.S. DOE CCT Program

This report is available on the Internet

at U.S. DOE, Office of Fossil Energy’s home page: www.fe.doe.gov

and on the Clean Coal Technology Compendium home page:

www.lanl.doe.gov/projects/cctc

To Receive Additional

Information

To be placed on the Department

of Energy’s distribution list for future

information on the Clean Coal Technology Program, the demonstration

projects it is financing, or other Fossil

Energy Programs, please contact:
24

List of Acronyms and Abbreviations

Btu. ............................................................. British thermal unit

CAAA ......................................................... Clean Air Act Amendments of 1990

CCT ............................................................ Clean Coal Technology

CO............................................................... carbon monoxide

CO2 ............................................................. carbon dioxide

COS ............................................................ carbonyl sulfide

DOE ............................................................ U.S. Department of Energy

EPA ............................................................ U.S. Environmental Protection Agency

HCl ............................................................. hydrogen chloride

HRSG ......................................................... heat recovery steam generator

H2S ............................................................. hydrogen sulfide

H2SO4 ......................................................... sulfuric acid

IGCC .......................................................... integrated gasification combined-cycle

kV ............................................................... kilovolt

kWh ............................................................ kilowatt hour

MWe ........................................................... megawatts of electric power

MWth.......................................................... megawatts of thermal power (1 MWth = 3.413x106 Btu/hr)

NETL .......................................................... National Energy Technology Laboratory

NOx ............................................................ nitrogen oxides

O2 ................................................................ oxygen

PM .............................................................. particulate matter

ppmv ........................................................... parts per million by volume

psig ............................................................. pressure, pounds per square inch (gauge)

SO2 ............................................................. sulfur dioxide

SO3 ............................................................. sulfur trioxide

syngas ......................................................... synthesis gas

TEC ............................................................ Tampa Electric Company

TPS ............................................................. TECO Power Services Corporation

VOC ............................................................ volatile organic compounds

wt % ............................................................ percent by weight