TOPICAL REPORT NUMBER 6 OCTOBER 1996

The Tampa Electric

Integrated Gasification

Combined-Cycle Project

Demonstration of an Advanced

250 Megawatt Integrated Gasification

Combined-Cycle Power Plant

A report on a project conducted jointly

under a cooperative agreement between:

The U.S. Department of Energy and Tampa Electric Company
Cover image: The Polk Power Plant site as seen from across the lake in early evening.

Photography courtesy of Lee Schmoe, Bechtel Power Corporation.

Preparation and printing of this document

conforms to the general funding provisions of

a cooperative agreement between Tampa

Electric Company and the U.S. Department of

Energy. The funding contribution of the

industrial participant permitted inclusion of

multicolored artwork and photographs at no

additional expense to the U.S. Government.
T E C H N O L O G Y

The Tampa Electric

Integrated Gasification

Combined-Cycle Project

Introduction and Executive Summary ........................................................................ 2

 Background ................................................................................................................ 4

Project Benefits ......................................................................................................... 6

Project Description .................................................................................................... 7

Environmental Considerations ................................................................................. 14

Costs/Schedule/Demonstration Milestones .............................................................. 15

Preliminary Results .................................................................................................. 16

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

Clean Coal Technology Program ............................................................................. 18

Contacts ................................................................................................................... 19

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

List of Acronyms and Abbreviations ....................................................................... 21
Introduction and

Executive Summary

Coal is America’s most abundant fossil

fuel. Its combustion creates the steam that

produces 65 percent of this country’s electricity. The burning of coal, however, liberates two types of gases that have been

linked to the formation of acid rain: nitrogen oxides (NOX) and sulfur dioxide (S02).

With the passage of each successive

piece of clean air legislation over the

years, the electric utility industry has been

made increasingly aware that it would

eventually have to reduce both types of

emissions from existing and new power

plants to environmentally acceptable

levels.

The Clean Coal Technology (CCT)

Demonstration Program is a government

and industry co-funded program to

furnish the U.S. energy marketplace

with advanced, more efficient and

environmentally responsible coalutilizing technologies.

A multi-phased effort consisting of five

separate solicitations was administered by

the U.S. Department of Energy (DOE).

Projects selected are a new generation of

innovative coal utilization processes that

are being demonstrated in "showcase"

projects conducted across the country.

These projects are on a scale sufficiently large to demonstrate commercial

worthiness and generate data for design,

construction, operation and technical/economic evaluation of full-scale commercial

applications.

2

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 technology that combines

modem coal gasification with gas turbine

and steam power generation technologies.

Syngas produced by a gasifier is cleaned

and burned in a gas turbine to produce

electric power. Heat recovered from the

hot turbine’s exhaust produces steam that

turns a steam turbine generator to produce

more electricity.

IGCC power plants are environmentally

acceptable and easily sited. Atmospheric

emissions of pollutants are 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 per megawatt-hour of output,

causing IGCC power plants to emit less

carbon dioxide (C02) to the atmosphere,

thereby decreasing global warming concerns. Less coal use also reduces

disposal requirements for ash or slag if

there is no market for these materials.

Repowering is an excellent application for IGCC. Such applications utilize

an existing power plant site and are more

economical than greenfield applications.

Costs are lower because an existing

steam turbine is used, less site development is required, and the permitting

process is accelerated.

Both greenfield and repowering IGCC

applications could provide the flexibility

needed for utility compliance planning for

sulfur dioxide (S02) emissions in the next

century. Providing 25 percent of coalbased electricity by IGCC would result in

emissions less than 0.4 million of the 11.8

million tons/yr of S02 emissions allowable

under the Clean Air Act Amendments

(CAAA).

Modularity and fuel flexibility are other

important attributes of IGCC power plants.

Before the gasifier is constructed, the

combined cycle unit can be operated on

other fuels, such as natural gas or fuel oil, to

provide early power. The size of gas

turbine units can be chosen to meet specific

power requirements. The ability to operate

on multiple fuels allows 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 reserves, and use of coal helps to

reduce dependence on foreign oil.

IGCC has potential for significant reduction in capital costs over today’s technologies, per kW of generation. These, in part,

arise from higher possible efficiencies compared to today’s impressive IGCC values.

Efficiency improvements are expected to

result from design improvements which

increase overall steam and thermal integration, use of higher firing temperature gas

turbines, and other technology enhancements such as hot-gas cleanup and nitrogen

injections. Other contributors to reduced

capital costs are: economies of scale, reduced engineering costs, and improvements

resulting from operating experience.
Executive Summary

 The Tampa Electric Integrated Gasification Combined-Cycle Project (the Project)

was selected by DOE as a CCT Program

Round III demonstration project. Demonstration of this advanced IGCC power plant

was initiated in October, 1996.

 The Participant is Tampa Electric

Company (TEC), headquartered in Tampa,

Florida. TEC signed a Cooperative Agreement with DOE to conduct the Project in

July 1992. Its service area includes the city

of Tampa and covers a 2000 square mile

area in west-central Florida.

The greenfield site is located south of

Lakeland, Polk County, Florida. The

Project is demonstrating use of Texaco’s

coal gasification process to fuel an advanced General Electric gas turbine generator whose exhaust is integrated with a

heat recovery steam generator (HRSG) and

a steam turbine generator to produce

electric power.

About 96 percent of sulfur contaminants

are removed by a combination of advanced

hot-gas cleanup and conventional cold-gas

cleanup technologies. Ninety percent of

the gasification product gas, termed syngas,

is cleaned by cold-gas cleanup and 10

percent by hot-gas cleanup. Sulfur is

recovered as sulfuric acid and sold, as is

the slag by-product of gasification.

TEC is demonstrating an advanced

moving bed hot-gas desulfurization technology because of its potential for improving IGCC performance and costs.

A primary potential advantage of hotgas cleanup is an increase in power plant

efficiency because cleaning does not

require the syngas to be cooled to nearambient temperature (used for cold-gas

cleanup) and resultant energy losses are

eliminated. Further, there is no process

waste water condensate.

The hot moving bed desulfurization

system being demonstrated in this

Project captures residual dust contained

in the fuel gas, and downstream sintered

metal barrier filters capture the balance.

In contrast to cold-gas cleanup, the

hot-gas cleanup technologies have not

yet been commercially demonstrated.

The combined cycle unit is based on

an advanced General Electric gas turbine

unit that produces 192 MWe. The steam

turbine produces 121 MWe. Parasitic

power consumes 63 MWe with the net

power output being 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 supplies various process needs. The facility processes approximately 2300 tons per day of Pittsburgh No.

8 bituminous coal, with a sulfur content of

2.5—3.5 percent.

S02 emissions will be 0.21 lb/million

Btu input; NOX emissions will be 0.27 lb/

million Btu input. The design heat rate of

the plant is an impressive 8600 Btu/kWh

(40 percent net thermal efficiency) on a

higher heating value basis. The cost of

the Project including land acquisition, site

development and allowance for funds

used during construction (AFUDC) is

about $506 million. DOE is providing

about $142 million.

The first two-year demonstration

period began in October, 1996 and will

involve testing four Eastern U.S. bituminous coals. The following two-year

period will involve continued development of operating/maintenance and reliability data on fuels selected by TEC.

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 C02 Emissions

• Public Acceptability

3
The Tampa Electric

Integrated Gasification

Combined-Cycle Project

Background

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 United States,

Texaco’s gasification technology is utilized

at Eastman Chemical’s Kingsport,

Tennessee facility. The product is a synthesis gas for production of methanol. The

Dakota Gasification plant in North Dakota

produces synthetic 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

4

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. about 25 years ago, the stimuli being

the desire for: (1) development of coalbased replacements for natural gas and oil

due to shortages and price increases; and

(2) more efficient, clean coal-based

power plants.

Modem IGCC technology is a response

of the 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 turbine exhaust

produces steam to generate additional

electricity.

Texaco coal gasification technology

stems from its partial oxidation

technology that was developed following

World War II, in which natural gas and

refinery bottoms were partially oxidized
at high temperatures to produce a

synthesis gas for refinery use.

The first commercial scale use

of a Texaco gasifier in a U.S. IGCC

project was the Cool Water project.

This project received major support

from the U.S. Synthetic Fuels

Corporation, Southern California

Edison Company, U.S. DOE,

Electric Power Research Institute,

Bechtel Power Corporation, and

others. The Cool Water project

was instrumental in proving the

feasibility of IGCC, including its

exceptionally good performance in

reducing atmospheric emissions.

Gas turbines for power generation have been one of the outgrowths of jet aircraft engine

development. At the end of 1994,

gas turbines contributed about

12 percent (59,600 MWe) of the

fossil fuel-based generating

capability of U.S. electric utilities.

Gas turbine generation capability

increased by 23 percent over the

period 1990-1994 even though

the total fossil-based generation

capability increased by only one

percent.

This increasing use is due to

technology advances, relatively

low cost per kW, and shorter construction time than conventional

generation. Advances in design

and materials have led to major increases in

the size and performance capability of gas

turbine units. Still more efficient models are

expected to be available in the near future.

DOE projects that, over the period of

1994-2015, the proportion and amount of

gas turbine and combined-cycle based

generation will increase. These will

constitute 78 percent (197,000 MWe) of the

projected total new capacity of utility plus

non-utility generators (252,000 MWe).

IGCC technologies demonstrated in the

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.

CCT program are expected to provide a

significant share of this new 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.

Atmospheric emissions are low due to

the availability of proven technologies for

highly effective removal of sulfur and

other contaminants from the fuel gas.

5
The sulfuric acid plant is located

in the foreground and the gasifier

and radiant syngas cooler are in

the tall midground structure.

New Generating Capacity Forecast

1994-2015

DOE projects that over the period 1994-2015, gas turbine and

combined-cycle based generation will be 78 percent (197,000

MWe) of the total new capacity additions of utility plus non-utility

generators (252,000 MWe).

Source: U.S. Energy Information Administration, 1996

6

Project Benefits

The Tampa Electric Integrated Gasification Combined-Cycle Project is expected

to demonstrate very low environmental impacts and will be one of the most efficient

power plants operating in the United States.

The 250 MWe output of the power

plant will help Tampa Electric Company

(TEC), the participant in this project with

the U.S. Department of Energy (DOE),

meet its customers’ needs and provide

low-cost base load power. Benefits will

be realized by both the customers and the

environment—customers through lowcost reliable power and the environment

because of very low emissions and relatively low use of natural resources.

A successful demonstration will help

to provide the impetus for future use of

IGCC technology throughout the U.S.

The Project participants will benefit

through sales and licensing of their

products.

The Project will also benefit the local

area. Approximately 1500 acres of the

plant site have been converted by TEC

from phosphate mining spoils to wetlands

and uplands. The restoration provides

habitat for native plants and animals.

A peak total of 1400 construction jobs

were created, and 75 full-time new jobs

were created for operation and maintenance of the IGCC power plant. Contract

labor is utilized as required for additional

maintenance.

There are new jobs for coal truck

drivers, and other secondary employment

related to plant operation. The economy

will benefit through payment of as much

as $7.0 million per year in additional taxes

by TEC.
Project Description IGCC Inputs and Outputs

Project Participant Inputs Quantity, tons/day

TEC is an investor owned electric utility

headquartered in Tampa, Florida. It is the

principal wholly owned subsidiary of

TECO Energy, Inc., an energy related

holding company heavily involved in coal

transportation and power generation.

TEC presently has about 3400 MWe

of generating capacity, about 99 percent

from coal-fired units. TEC serves an area

of about 2000 square miles in west central

Florida. TECO Power Services (TPS), another subsidiary of TECO Energy, operates a 295 MWe natural gas fired combined cycle power plant in Florida, with

the electric power being sold under longterm power sales agreements.

TPS developed the Project and has been

performing project management

throughout. Under terms of the

Cooperative Agreement TPS plans to

commercialize the Project IGCC

Major Participants

TEC has selected major technology

suppliers for this project that are experienced and successful in their respective

industries. They include Texaco Development Corporation, as the licensor of the

coal gasification technology and related

services; Bechtel Power Corporation, for

detailed engineering, procurement, startup and construction management; General

Electric, as the supplier of combined cycle

equipment; and GE Environmental

Services, Inc., designer of the hot-gas

cleanup system.

Site Description

The Project is Unit I of the new Polk

Power Plant, located in south central Polk

Coal 2000

Oxygen 1974

Slurry water (recycled) 884

Nitrogen to gas turbine 6024

Solids Output

Slag/fines from dewatering pit 311

Dry solids from brine concentrator 2.8

98% Sulfuric Acid 218

Net Electrical Output 250 MWe

Major Participants

Owner/operator

Project management and commercialization

Licensor of gasification technology

Supplier of gas turbine/combined

cycle equipment

Tampa Electric Company

TECO Power Services Corporation

Texaco Development Corporation

General Electric Corporation

GE Environmental Services, Inc.

Bechtel Power Corporation

MAN Gutehoffnüngshutte AG

L. & C. Steinmbller Gmbh

Air Products & Chemicals, Inc.

Monsanto Enviro-Chem Systems, Inc.

H.B. Zachry Company

The Industrial Company

Johnson Brothers Corporation

Aqua-Chem, Inc.

Davenport Mammoet

Heavy Transport

Designer of hot-gas cleanup system

Detailed engineering/construction

management services, procurement,

and startup

Supplier of radiant syngas cooling system

Supplier of convective syngas cooling system

Turnkey supplier for air separation unit

Turnkey supplier for sulfuric acid plant

Power block construction

Gasification area construction

Site development and civil contractor

Supplier of brine concentration plant

Transportation/erection of radiant

syngas cooler

7
A single Texaco gasifier processes 2000 tons per day of coal at about

2500-2700°F (1371°-1482°C) 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.

8

County, central Florida. The 4348 acre

site is located 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

was previously mined for phosphate rock

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

The site area is predominantly rural.

Polk County is an important citrus-raising

and phosphate mining center, each being

important Florida industries.

About a third of the site is used for

power generation facilites. Another third

is used to enhance the environment by

creation of public fishing lakes for the

Florida Fish and Game Commission. Transfer of these 1511 acres is expected to take

place before April 1997. The final third of

the site is primarily for access and providing

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.

Power Plant Description

The Project is demonstrating advanced

IGCC technology for production of 250 MWe

in a commercial, electric utility environment

on a greenfield site. It is demonstrating the

integrated performance of a Texaco gasifier,

metal oxide hot-gas cleanup system, conventional cold-gas cleanup, and an advanced gas turbine with nitrogen injection

(from the air separation plant) for power

augmentation and NOX control.

Makeup water for the power plant is

provided from on-site wells. All process

water is recycled.

Texaco gasifier

Coal is delivered to the site by truck

from a transloading facility at TEC’s Big

Bend Station in Apollo Beach, Florida.

Once on site, the coal is conveyed from

coal silos and fed to the grinding mill
with recycled process water and makeup

water from on-site wells.

The project gasifies about 2000 tons

per day of coal in a single gasifier. The

Texaco gasifier has been commercially

proven in several applications and the

scaleup, of less than a factor of two, to

this throughput is not considered to pose

 a high level of risk.

Coal is slurried in water, and reacted

in the gasifier with 95 percent pure oxygen (from the air separation unit) to produce a high temperature, high pressure,

medium-Btu synthesis gas, also known as

syngas.

The raw syngas is partly cooled by a

high temperature radiant heat recovery

unit prior to subsequent cooling stages.

Molten coal ash flows from the bottom of

the radiant syngas cooler into a water-filled

quench chamber where it solidifies into a

marketable slag by-product. The slag has

been found by the U.S. Environmental Protection Agency (EPA) to be non-leaching.

After additional cooling of the raw syngas stream in parallel convective heat exchangers the stream is split into streams for

both hot- and cold-gas cleanup to remove

sulfur compounds and other contaminants.

Cold-gas cleanup

Cold-gas clean-up is the primary

method because the specific technologies

utilized are proven effective, reliable and

commercially available.

Ninety percent of the syngas is cleaned

by the cold-gas cleanup, but the system is

designed to accommodate the full production of syngas if performance of the hotgas cleanup system is unacceptable.

Typical Coal Analysis

(Pittsburgh No. 8 Seam)

Ultimate Analysis As-Received, wt%

9

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

 As-Received

 Higher Heating Value, Btu/Ib 13,290
The raw hot syngas is cooled to 100°F

for cold-gas cleanup by conventional acid

gas removal technology. This portion of

the plant is based upon absorption of H

2

S

by a liquid amine compound and is capable

of processing 100 percent of the syngas

produced by the gasifier. Steam stripping

removes the absorbed H

2S which then

flows to the sulfuric acid plant.

Hot-gas cleanup

The potential advantage of hot-gas

cleanup is that it increases overall power

plant thermal efficiency because energy

losses in cooling the syngas to near ambient

temperature (used for cold-gas cleanup) are

eliminated. Costs are reduced compared to

cold-gas cleanup because less gas cooling

and other process equipment is needed.

To evaluate these potential benefits,

TEC included hot-gas cleanup to clean

10 percent of the syngas. GE Environmental Services' advanced intermittently

moving bed hot-gas cleanup system is

utilized. This technology and the sorbents

used show important promise but are not

yet proven in commercial operation.

In the hot-gas cleanup system, the

syngas first passes through two cyclones to

remove entrained dust. Sodium bicarbonate (NaHCO3) is added before the

second cyclone to capture trace amounts of

chlorides and fluorides in the syngas for

protection of gas turbine components.

The hot-gas desulfurization unit operates at 900°F (482°C). It is an intermittently moving bed of a metal oxide based

sorbent that removes sulfur-containing

compounds (mainly hydrogen sulfide

[H

2S]) and residual dust in the syngas.

Regeneration of the metal sulfides

produced by syngas desulfurization takes

place in a separate vessel utilizing oxygen

and nitrogen. The original metal oxide is

restored and the product sulfur dioxide

(S0

2) flows to the sulfuric acid plant.

Installation of radiant syngas cooler.

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This is the first unit to demonstrate

advanced moving bed metal oxide hotgas desulfurization technology on a

commercial scale.

Power island

Combined, the cleaned syngas streams

have a heating value of about 265 Btu per

standard cubic foot (higher heating value

basis). It is sent to the advanced General

Electric model MS 7001F gas turbine of

the combined cycle power island where it

is burned. About 192 MWe of electric

power is produced. The pressure of the

gasifier was selected to match the inlet

pressure requirement of the gas turbine.

Nitrogen from the air separation unit (at

98 percent purity) is mixed with the syngas

at the gas turbine combustor to give the

following benefits to the power plant: (1)

the enhanced mass flow through the gas

turbine produces more power than without

the nitrogen; (2) the overall efficiency of

the system is enhanced; and (3) low levels

of NOX emissions are obtained.

Hot exhaust from the gas turbine unit

passes through a heat recovery steam

generator (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 a reheat steam

turbine-generator to produce about 121

MWe. Flue gas exits through a 150 foot

stack. A flare is provided to dispose of

syngas produced during startup, shutdown,

and during transient operations.

Power consumption within the

facility is 63 MWe, resulting in a net

power output of 250 MWe.

The net power plant heat rate is an

impressive 8600 Btu/kWh (about 40 percent efficiency), higher heating value basis. A 230 kV, five-mile transmission line

connects the power plant to the TEC grid.

Simplified Chemistry

TEXACO GASIFIER

C (coal) + O2 2700°F CO2 + Heat

C (coal) + H2O (steam) 2700°F CO + H2

HOT GAS CLEANUP

Desulfurization

MO + H2S 900°F MS + H2O

(metal oxide) (metal sulfide)

MO + COS 900°F MS + CO2

Regeneration

MS + 1.5 O2 1200°F MO + SO2

Other operations

The sulfuric acid plant converts the

SO2 and H2S from the hot- and cold-gas

cleanup systems to sulfuric acid which is

sold in the sulfuric acid trading market.

Production is about 200 tons per day.

A brine concentration unit processes

a blowdown stream discharged from the

process water systems and discharges a

reusable water stream for slurry preparation and salts which will be marketed

or disposed of in a permitted landfill.

General Electric model MS 7001F gas turbine

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Cleaned Syngas Composition

Delivered to Gas Turbine, Volume %

Constituent Hot-Gas Cleanup Cold-Gas Cleanup

Carbon monoxide

Hydrogen

Carbon dioxide

Methane

Water

Nitrogen

Argon

Hydrogen sulfide

Carbonyl sulfide

Ammonia

35.6

27.0

12.6

 0.1

18.6

5.8

0.0

 94.0 ppmv

0.0

 0.1 ppmv

 48.3

33.8

10.0

0.2

0.5

6.1

1.1

8.4 ppmv

 127.0 ppmv

0.0 ppmv

About 10 percent of the syngas is cleaned by hot-gas cleanup

and up to 100 percent by cold-gas cleanup.

General Electric Intermittent Moving Bed Hot Gas Desulfurization System.

12

Process Description

Texaco Gasification

Texaco coal gasification technology uses

a single-stage, downward-firing, entrainedflow coal gasifier in which a coal/water slurry

(60-70 percent coal) and 95 percent pure

oxygen are fed to a hot gasifier. At a temperature of about 2700°F (1482°C), the coal reacts with oxygen to produce raw fuel gas

(syngas) and molten ash.

The hot gas flows downward into a radiant

syngas cooler where high pressure steam is

produced. The syngas passes over the surface of a pool of water at the bottom of the

radiant syngas cooler and exits the vessel.

The slag drops into the water pool and is fed

from the radiant syngas cooler sump to a

lockhopper.The radiant syngas cooler is about

17 feet in diameter, 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.

Gas Cleanup

Gas cleanup equipment in an IGCC power

plant is relatively inexpensive compared to flue

gas cleanup in a conventional coal-steam

power plant. Smaller equipment is required

because a much smaller volume of gas is

cleaned.

The gas volume is smaller because contaminants are removed from the pressurized

fuel gas before combustion. In contrast, the

volume of flue gas from a coal-steam power

plant is 40–60 times greater because the flue

gas is cleaned at atmospheric pressure.

Cold-Gas Cleanup

The raw syngas exiting the radiant syngas cooler is first sent to parallel convective

syngas coolers. Ninety percent of the syngas

flows to the cold-gas cleanup system where

it is first treated in water scrubbers for removal of entrained solids and the gas then

flows to the low temperature syngas cooling
system. 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 form

that is shipped off-site either for reuse or

disposal in a permitted landfill. The separated water is recycled for slurry coal feed.

The particulate-free gas is water-washed

to remove contaminants that would degrade

the sorbent in the absorber. The wash water

is sent to the ammonia stripper. The washed

syngas flows to the amine absorber where

the H2S and some of the CO2 (acid gases)

are 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.

The cold-gas cleanup system is designed

to accept 100 percent of the raw syngas.

Hot-Gas Cleanup

This unit is designed to handle 10 percent

of the hot, raw syngas. Entrained fine particles in the hot syngas are removed in the

primary cyclone and sent to the "black"

water handling system. The exiting gas is

injected with sodium bicarbonate and then

enters a secondary cyclone where halogen

compounds (primarily chlorides and fluorides) in the gas are chemically absorbed.

Halogens are removed to minimize corrosion of the gas turbine. Solids collected from

the second cyclone are sent off-site for

disposal in a permitted landfill and the gas

flows to the absorber.

A large fraction of any remaining particulate matter entering the absorber is captured

by the bed of mixed metal oxide sorbent.

The absorber is an intermittently moving

bed reactor. Syngas, containing H2S and

carbonyl sulfide (COS), enters the bottom of

the absorber and flows countercurrent to the

moving bed of sorbent pellets. The sulfur

compounds react with sorbent to form metal

sulfides. Syngas exiting the absorber is

expected to contain a maximum of 30 parts

per million of H2S and COS.

Regeneration of the spent sorbent is

important to avoid excessive sorbent

replacement costs. In this part of the hot

gas cleanup process the sulfide is converted back to the oxide.

Sulfided sorbent is fed from the absorber

lockhopper to the top of the regenerator

where oxidation occurs. The sorbent moves

down the regenerator in concurrent flow with

the regeneration gas.

Temperature control is important to prevent damage to the sorbent structure at

temperatures that are too high. Conversion

of metal sulfide to the inactive sulfate occurs

at temperatures that are too low.

The final regeneration step occurs at the

lower stage of the regenerator where nitrogen flows countercurrent to the sorbent. This

stream cools the sorbent, purges the

SO2-rich off gas and ensures complete

regeneration without sulfate formation

Recycled regenerator effluent gas is

used as a diluent for air to control the

temperature by means of a heat exchanger

in the loop. Steam is generated and utilized

in the combined cycle unit. A small amount

of sorbent fines is entrained in the gas

stream and collected in a high efficiency

barrier filter that removes fines larger than

five microns (99.5 percent removal of particulates). Collected solids are sent offsite

for disposal.

Larger sorbent particles entrained in the

gas stream are collected on screens at the

regenerator sorbent outlet; fugitive fines from

the screens are collected in a small

baghouse.

Combined Cycle

Power Generation

The gas turbine is a General Electric

model MS 7001F, designed for low-NOX

emissions when firing sygnas and with low

sulfur fuel oil that is used for startup and

backup. Rated output from the hydrogen

cooled generator on syngas is 192 MWe.

The gas turbine is an advanced turbine that

has been proven in a utility environment.

Nitrogen is used as a syngas diluent to

reduce NOX formation and also to increase

mass flow, resulting in a higher gas turbine

power output.

The HRSG is a three-pressure design

with natural circulation and reheat. The

steam turbine is a double flow reheat unit

with low pressure extraction. Nominal steam

inlet conditions are 1450 psig and 1000°F

with 1000°F reheat temperature. Expected

generator output during normal operation

is 121 MWe.

Air Separation Unit

The air separation unit provides 95

percent pure oxygen for the gasifier

operation, and warmed compressed

nitrogen for the gas turbine. Low pressure

95 percent oxygen is also supplied to the

sulfuric acid plant.

Sulfuric Acid Plant

In the sulfuric acid plant, the sulfur

containing gases from the hot- and cold-gas

cleanup systems are converted to 98

percent sulfuric acid for sale to the local

Florida fertilizer industry. The H2S from the

cold-gas cleanup unit is combusted to SO2

and mixed with hot gases containing SO2

from the hot-gas cleanup unit. The combustion product gas stream, which also contains sulfur trioxide (S03) and sulfuric acid

(H2SO4), is cooled.

The gas is converted to 98 percent

H2SO4 (about 200 tons per day are produced) after passing through three catalyst

beds charged with vanadium pentoxide

catalyst. Oxygen is utilized for conversion of

SO2 to SO3 in the process. After separation of H2SO4, the concentration of SO2

remaining in the gas stream is low enough

to permit direct discharge to the atmosphere through a 200 foot stack.

13
Environmental

Considerations

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

The Tampa Electric Integrated Gasification Combined-Cycle Project is designed to have low environmental impacts. Emissions to the atmosphere are

low because they are controlled by technologies that are very effective.

The site was selected by an independent Community Siting Task Force, commissioned by TEC. Members included

environmentalists, educators, economists,

and community leaders. Environmental

impact was a primary driver in the choice

of acceptable sites for the plant. Economic

factors were also considered. The Task

Force considered 35 sites in six counties

and recommended three in southwestern

Polk County that had previously been

mined for phosphate.

The U.S. Environmental Protection

Agency (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, U.S. Army Corps of Engineers,

and DOE by August, 1994. Some of the

inputs for this comprehensive document

were provided by TEC and its environmental consultants .

All federal, state, and local environmental permits have been obtained. An

Environmental Monitoring Plan developed

by TEC gives details of the performance

monitoring of environmental control

equipment, stack emissions, and also for

the site and surrounding area.

14
Costs/Schedule/

Demonstration

Milestones

The estimated cost of the Tampa Electric

Integrated Gasification Combined-Cycle

Project including the operation and testing

phase is approximately $506 million. DOE

is providing about $142 million.

Work on the project was initiated with

the completion of an agreement between

TEC and DOE in July 1992. Site, environmental and permitting, engineering, procurement and construction activities were

completed since then. Groundbreaking

took place in November, 1994, and the

facility was released to operations in

October 1996.

The four-year demonstration program

began in October, 1996. Data are being

gathered on power plant performance,

including environmental performance.

Operation will be on four Eastern U.S.

bituminous coals. Data will be collected

involving systems performance and operating and maintenance costs. Information on

startup, shut down and ramp rates will be

gathered and evaluated. Behavior of the

gas cleanup systems will be established

and emissions monitored.

Selected Startup

Milestones Achieved

• Initial roll of the steam turbine:

June,1996

• Sulfuric acid plant and gasifier

completion: June, 1996

• Completion of the hot-gas

cleanup system: July, 1996

• Start demonstration program:

October, 1996

Allowed Stack Emissions

(at 15 percent excess oxygen)

Allowed Emissions, pounds/hour

Pollutant

SO2

NOX

CO

VOC

PIVI/PM-10

During First

Two Years of

Demonstration

518

664

 99

 3

 17

After First

Two Years of

Demonstration

357

223

 98

 3

 17

Power Output

Gas Turbine

Steam Turbine

192 MWe

121 MWe

Gross

Auxiliaries Power Use

 313 MWe

 63 MWe

Net Power Output 250 MWe

Gas turbine, model MS 7001F, during manufacture.

15
Gasifier Run Summary

Start Date Major Accomplishments

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.

Preliminary Results

All construction activities at the Polk

Power Plant have been completed. TEC

also completed the reclamation of wetlands on both sides of State Highway 37

that crosses the site.

The Project power plant entered the

demonstration phase in October 1996.

Operating on a Pittsburgh No. 8 bituminous coal, results achieved have been

positive and encouraging.

A 101.6 hour run of the lGCC system

was conducted in mid-October. Long

term stable operation and full capacity

were achieved. These are critical elements

of the demonstration since they are necessary precursors to the conduct of acceptance tests for the coal-gas cleanup and

sulfuric acid plant systems downstream

of the gasifier.

Operating on syngas as well as distillate

fuel, the unit has achieved full load on the

combustion turbine and steam turbine. As

planned, the combustion turbine achieved

the design values of 192 MWe on syngas,

and 121 MWe from the steam turbine, for a

total output of 313 MWe. The nitrogen

injection system operated as expected.

As of the end of October, 1996 the unit

was operated only in the cold-gas cleanup

mode. Work continues on check-out of the

hot-gas cleanup systems and equipment; as

of the publication date sorbent was loaded

and attrition testing underway.

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.

16
Controls tuning continues and when completed, performance testing of the IGCC system and equipment will be conducted.

As a result of its solid operating experience in the test program, the combined

cycle unit has been made available for

operation on distillate fuel to help meet

TEC’s load on an as-needed basis.

By-product evaluation is in progress.

The brine concentration system has produced chloride crystals which will be

evaluated by potential purchasers for reuse.

The sulfuric acid plant has produced sulfuric

acid which will be sold through the sulfuric

acid trading market in Florida. The slag is

being evaluated by the purchaser to determine how it will be utilized.

Testing of the IGCC system is planned

to optimize operation, improve overall

cycle efficiency and achieve emission

targets. TEC will begin with parametric

testing of key subsystems, including the

hot-gas cleanup system. Four types of

coals will be used in accordance with the

demonstration test plan.

Dawn arrives over the

reclaimed wetlands surrounding the Tampa

Electric Integrated Gasification Combined-Cycle

Project

Future Developments

The achievements and knowledge

gained from the Tampa Electric Integrated Gasification Combined-Cycle

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

commercial offerings of the technology

would be expected to be lower in cost

and improved in performance.

DOE believes that future IGCC greenfield power plants, based upon mature and

improved technology, will cost in the

range of $1000-1350/kW (1995 basis).

Heat rate is expected to be in the range of

7000-7500 Btu/kWh (46-49 percent

efficiency), higher heating value basis.

Costs will be further reduced if an existing

steam turbine is repowered and existing

site infrastructure utilized.

17
The Clean Coal Technology Program

The Clean Coal Technology (CCT)

Program is a unique partnership between the federal government and industry that has as its primary goal the

successful introduction of new clean

coal utilization technologies into the

energy marketplace. With its roots in

the acid rain debate of the 1980s, the

program is on the verge of meeting its

early objective of broadening the

range of technological solutions available to eliminate acid rain concerns

associated with coal use. Moreover,

the program has evolved and has

been expanded to address the need

for new, high-efficiency power-generating technologies that will allow coal

to continue to be a fuel option well into

the 21st century.

Begun in 1985 and expanded in

1987 consistent with the recommendation of the U.S. and Canadian Special

Envoys on Acid Rain, the program has

been implemented through a series of

five nationwide competitive solicitations. Each solicitation has been

associated with specific government

funding and program objectives. After

five solicitations, the CCT Program

comprises a total of 40 projects located

in 18 states with a capital investment

value of nearly $6.0 billion. DOE’s

share of the total project costs is about

$2.0 billion, or approximately 34 percent

of the total. The projects’ industrial

participants (i.e., the non-DOE participants) are providing the remaindernearly $4.0 billion.

Clean coal technologies being

demonstrated under the CCT Program are establishing a technology

base that will enable the nation to

meet more stringent energy and

environmental goals. Most of the

demonstrations are being conducted

at commercial scale, in actual user

environments, and under circumstances typical of commercial

operations. These features allow

the potential of the technologies to

be evaluated in their intended commercial applications. Each application addresses one of the following

four market sectors:

• Advanced electric power

generation

• Environmental control devices

• Coal processing for clean fuels

• Industrial applications

Given its programmatic success,

the CCT Program serves as a model

for other cooperative government/

industry programs aimed at introducing new technologies into the

commercial marketplace.

18
Contacts

Project Team Members

Tampa Electric Company

U.S. Department of Energy

Donald E. Pless

Director, Advanced Technology

TECO Power Services Corp.

P.O. Box 111

Tampa, FL 33601-0111

(813) 228-1330

(813) 228-1308 fax

George E. Lynch

Portfolio Manager for

Gasification Power Systems

U.S. Department of Energy

Office of Coal & Power Systems

FE-221/27OCC

19901 Germantown Road

Germantown, MD 20874-1290

(301) 903-9434

(301) 903-9438 fax

george.lynch @hq.doe.gov

Nelson F. Rekos

Project Manager

U.S. Department of Energy

Federal Energy Technology Center

P.O. Box 880

Morgantown, WV 26507-0880

(304) 285-4066

(304) 285-4403 fax

nrekos@metc.doe.com

Charles M. Zeh

IGCC Product Manager

Federal Energy Technology Center

P.O Box 880

Morgantown, WV 26507-0880

(304) 285-4265

(304) 285-4403 fax

czeh@metc.doe.gov

To be placed on the Department of Energy’s distribution list for future information on the Clean Coal Technology

Program and the demonstration projects it is financing or on other Fossil Energy programs, please contact:

Victor Der

Director, Office of Power Systems

U.S. DOE, Office of Fossil Energy

Washington, DC 20585

(301) 903-2700

(301) 903-2713 fax

victor.der@hq.doe.gov

This report is available on the Internet

at www.lanl.gov/projects/cctc

19
Bibliography

 Black, C.R., "Polk Status Update,"

Twelfth EPRI Conference on Coal Gasification Power Plants (San Francisco CA),

October 1993.

Black, C.R., "Tampa Electric Company’s

Polk Power Station Construction Update,"

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

Energy Information Administration, Office

of Integrated Analysis and Forecasting,

"Annual Energy Outlook 1996 with Projections to 2015," pp. 29, 38, DOE/FE0346, January 1996.

"IGCC Takes a Bold Leap Forward,"

Power, pp. 81-84, April 1996.

Jenkins, S., "Tampa Electric Company

Polk Power Station IGCC Project,"

Twelfth Annual International Pittsburgh

Coal Conference (Pittsburgh PA),

September 1995.

Jenkins S.D., "Polk Power Station Syngas

Cooling System," Eleventh Worldwide

Texaco Gasification Licensee Symposium

(White Plains NY), October 1994.

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

Pless, D.E., "Polk Status Update," U.S.

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

20

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

Station" U.S. DOE Fourth Annual Clean

Coal Technology Conference (Denver CO),

September 1995.

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

"Turbine Developments for IGCC Applications, Status Update," Thirteenth EPRI

Conference on Coal Gasification Power

Plants (San Francisco CA), October 1994.

Stambler, I., "Progress in IGCC and

Advanced Cycles Outlined at EPRI Meeting," Gas Turbine World, pp. 16-23,

January-February 1996.

Swanekamp, R., "Startup of Large-Scale

Projects Casts Spotlight on IGCC," Power,

pp. 59-68, June 1996.

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Gasification Combined Cycle (IGCC)

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Station Unit No. 1," Annual Report,

October 1993-September 1994, May 1995.

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October 1992.

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1992.

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26, 7-27; DOE/EIA-0383(96), April 1996.

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Station," EPA 904/9-94-002(b), June 1994.
List of Acronyms and Abbreviations

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

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

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

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

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

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

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

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

MWe ............................................................................................megawatt electric

ppmvd ................................................................... parts per million by volume, dry

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

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

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

PM-10 ..............................particulate matter less than 10 micrometers in diameter

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

21