Integrated Gasification
Combined Cycle Clean
Coal Technology & The President's Clean
Coal Power Initiative
"Clean
Coal Technology" describes a new generation of energy processes that
sharply reduce air emissions and other pollutants compared to older coal-burning
systems. In the late 1980s and early 1990s, the U.S. Department of Energy
conducted a joint program with industry and State agencies to demonstrate the
best of these new clean
coal technologies at scales large enough for companies to make
commercial decisions. More than 20 of the technologies tested in the original
program achieved commercial success. The
early program, however, was focused on the environmental challenges of the time
- primarily concerns over the impact of acid rain on forests and watersheds. In
the 21st century, additional environmental concerns have emerged - the potential
health impacts of trace emissions of mercury, the effects of microscopic
particles on people with respiratory problems, and the potential global
climate-altering impact of greenhouse
gas emissions. With
coal likely to remain one of the nation's lowest-cost electric power suppliers
for the foreseeable future, President Bush has pledged a new commitment to even
more advanced clean coal
technologies. As the President said in presenting his
National Energy Policy to the American public on Building
on the successes of the original program, the new clean coal initiative
encompasses a broad spectrum of research and large-scale projects that target
today's most pressing environmental challenges. Initially, the demonstration portion of the program, the Clean Coal Power Initiative, is providing government co-financing for new coal technologies that can help utilities meet the President's Clear Skies Initiative to cut sulfur, nitrogen and mercury pollutants from power plants by nearly 70 percent by the year 2018. Also, some of the early projects are showing ways to reduce greenhouse gas emissions from coal plants by boosting the efficiency at which they convert coal to electricity or other energy forms. Coal
gasification
offers one of the most versatile and cleanest ways to convert
the energy content of coal into electricity, hydrogen, and other energy forms. The first pioneering coal gasification electric power plants are now operating commercially in the United States and in other nations, and many experts predict that coal gasification will be at the heart of the future generations of clean coal technology plants for several decades into the future. For example, at the core of the U.S. Department of Energy's FutureGen power plant of the future will be an advanced coal gasifier. Rather
than burning coal directly, gasification breaks down coal - or virtually any
carbon-based feedstock - into its basic chemical constituents. In a modern
gasifier, coal is typically exposed to hot steam and carefully controlled
amounts of air or oxygen under high temperatures and pressures. Under these
conditions, carbon molecules in coal break apart, setting into motion chemical
reactions that typically produce a mixture of carbon monoxide, hydrogen and
other gaseous compounds. Coal Gasification, in fact, may be one of the best ways to produce clean-burning hydrogen for tomorrow's automobiles and power-generating fuel cells. Hydrogen and other coal gases can also be used to fuel power-generating turbines or as the chemical "building blocks" for a wide range of commercial products. The
Energy Department's Office of Fossil Energy is working on coal gasifier advances
that enhance efficiency, environmental performance, and reliability as well as
expand the gasifier's flexibility to process a variety of feedstocks (including
biomass and municipal/industrial waste). Environmental
Benefits The
environmental benefits stem from the capability to cleanse as much as 99 percent
of the pollutant-forming impurities from coal-derived gases. Sulfur in coal, for
example, emerges as hydrogen sulfide and can be captured by processes used today
in the chemical industry. In some methods, the sulfur can be extracted in a form
that can be sold commercially. Likewise, nitrogen typically exits as ammonia and
can be scrubbed from the coal gas by processes that produce fertilizers or other
ammonia-based chemicals. The
Office of Fossil Energy is also exploring advanced synethesis
gas cleaning and conditioning processes that are even more effective in
eliminating emissions from coal gasifiers. Multi-contaminant control processes
are being developed that reduce pollutants to parts-per-billion levels and are
effective in cleaning mercury and other trace metals in addition to other
impurities. Coal
gasification
may offer a further environmental advantage in addressing
concerns over the atmospheric buildup of greenhouse
gas emissions, such as carbon
dioxide emissions. If oxygen is used in a coal gasifier instead of air,
carbon dioxide is emitted as a concentrated gas stream. In this form, it can be
captured more easily and at lower costs for ultimate disposition in various
sequestration approaches. (By contrast, when coal burns or is reacted in air, 80
percent of which is nitrogen, the resulting carbon dioxide is much more diluted
and more costly to separate from the much larger mass of gases flowing from the
combustor or gasifier.) Efficiency
Benefits Efficiency
gains are another benefit of coal gasification. In a typical coal combustion
plant, heat from burning coal is used to boil water, making steam that drives a
steam turbine-generator. Only a third of the energy value of coal is actually
converted into electricity by most combustion plants, the rest is lost as waste
heat. A
coal gasification power plant,
however, typically gets dual duty from the gases it produces. First, the coal
gases, cleaned of their impurities, are fired in a gas turbine - much like
natural gas - to generate one source of electricity. The hot exhaust of the gas
turbine is then used to generate steam for a more conventional steam
turbine-generator. This dual source of electric power, called a "combined
cycle," converts much more of coal's inherent energy value into useable
electricity. The fuel efficiency of a coal gasification power plant can be
boosted to 50 percent or more. Future
concepts that incorporate a fuel cell or fuel cell-gas turbine hybrid could
achieve even higher efficiencies, perhaps in the 60 percent range, or nearly
twice today's typical coal combustion plants. And if any of the remaining waste
heat can be channeled into process steam or heat, perhaps for nearby factories
or district heating plants, the overall fuel use efficiency of future
gasification plants could reach 70 to 80 percent. Higher
efficiencies translate into more economical electric power and potential savings
for ratepayers. A more efficient plant also uses less fuel to generate power,
meaning that less carbon dioxide is produced. In fact, coal gasification power
processes under development by the Energy Department could cut the formation of
carbon dioxide by 40 percent or more compared to today's conventional
coal-burning plant. The capability to produce electricity, hydrogen, chemicals, or various combinations while virtually eliminating air pollutants and potentially greenhouse gas emissions makes coal gasification one of the most promising technologies for the energy plants of tomorrow. COAL
is our most abundant fossil fuel. The But coal is not a perfect fuel. Trapped inside coal are traces of impurities like sulfur and nitrogen. When coal burns, these impurities are released into the air. While floating in the air, these substances can combine with water vapor (for example, in clouds) and form droplets that fall to earth as weak forms of sulfuric and nitric acid – scientists call it "acid rain." There are also tiny specks of minerals – including common dirt – mixed in coal. These tiny particles don't burn and make up the ash left behind in a coal combustor. Some of the tiny particles also get caught up in the swirling combustion gases and, along with water vapor, form the smoke that comes out of a coal plant's smokestack. Some of these particles are so small that 30 of them laid side-by-side would barely equal the width of a human hair! Also, coal like all fossil fuels is formed out of carbon. All living things - even people - are made up of carbon. (Remember - coal started out as living plants.) But when coal burns, its carbon combines with oxygen in the air and forms carbon dioxide. Carbon dioxide is a colorless, odorless gas, but in the atmosphere, it is one of several gases that can trap the earth's heat. Many scientists believe this is causing the earth's temperature to rise, and this warming could be altering the earth's climate, due to Greenhouse Gas Emissions, and the "Greenhouse Effect." Sounds like coal is a dirty fuel to burn. Many years ago, it was. But things have changed. Especially in the last 20 years, scientists have developed ways to capture the pollutants trapped in coal before the impurities can escape into the atmosphere. Today, we have technology that can filter out 99 percent of the tiny particles and remove more than 95 percent of the acid rain pollutants in coal. We also have new technologies that cut back on the release of carbon dioxide by burning coal more efficiently. Many of these technologies belong to a family of energy systems called "clean coal technologies." Since the mid-1980s, the U.S. Government has invested more than $2 billion in developing and testing these processes in power plants and factories around the country. Private companies and State governments have been part of this program. In fact, they have contributed more than $4 billion to these projects. How do you make "Clean Coal"? Actually there are several ways. And we call these technologies, "Clean Coal Technologies." Take
sulfur, for example. Sulfur is a yellowish substance that exists in tiny amounts
in coal. In some coals found in For
some coals found in
One way is to clean the coal before it arrives at the power plant. One of the ways this is done is by simply crushing the coal into small chunks and washing it. Some of the sulfur that exists in tiny specks in coal (called "pyritic sulfur " because it is combined with iron to form iron pyrite, otherwise known as "fool's gold) can be washed out of the coal in this manner. Typically, in one washing process, the coal chunks are fed into a large water-filled tank. The coal floats to the surface while the sulfur impurities sink. There are facilities around the country called "coal preparation plants" that clean coal this way. Not all of coal's sulfur can be removed like this, however. Some of the sulfur in coal is actually chemically connected to coal's carbon molecules instead of existing as separate particles. This type of sulfur is called "organic sulfur," and washing won't remove it. Several process have been tested to mix the coal with chemicals that break the sulfur away from the coal molecules, but most of these processes have proven too expensive. Scientists are still working to reduce the cost of these chemical cleaning processes. Most modern power plants — and all plants built after 1978 — are required to have special devices installed that clean the sulfur from the coal's combustion gases before the gases go up the smokestack. The technical name for these devices is "flue gas desulfurization units," but most people just call them "scrubbers" — because they "scrub" the sulfur out of the smoke released by coal-burning boilers. How do scrubbers work? Most scrubbers rely on a very common substance found in nature called "limestone." We literally have mountains of limestone throughout this country. When crushed and processed, limestone can be made into a white powder. Limestone can be made to absorb sulfur gases under the right conditions — much like a sponge absorbs water. In most scrubbers, limestone (or another similar material called lime) is mixed with water and sprayed into the coal combustion gases (called "flue gases"). The limestone captures the sulfur and "pulls" it out of the gases. The limestone and sulfur combine with each other to form either a wet paste (it looks like toothpaste!), or in some newer scrubbers, a dry powder. In either case, the sulfur is trapped and prevented from escaping into the air. The Clean Coal Technology Program tested several new types of scrubbers that proved to be more effective, lower cost, and more reliable than older scrubbers. The program also tested other types of devices that sprayed limestone inside the tubing (or "ductwork') of a power plant to absorb sulfur pollutants. But what about nitrogen pollutants? That's another part of the Clean Coal story. Knocking the Nitrogen Oxides (NOx) Out of Coal
Nitrogen is the most common part of the air we breathe. In fact, about 80% of the air is nitrogen. Normally, nitrogen atoms float around joined to each other like chemical couples. But when air is heated — in a coal boiler's flame, for example — these nitrogen atoms break apart and join with oxygen. This forms "nitrogen oxides" — or, as it is sometimes called, "NOx." Nitrogen oxides can also be formed from the atoms of nitrogen that are trapped inside coal. In the air, nitrogen oxides are a major pollutant. It can cause smog, the brown haze you sometimes see around big cities. It is also one of the pollutants that forms "acid rain." And it can help form something called "groundlevel ozone," another type of pollutant that can make the air dingy. NOx can be produced by any fuel that burns hot enough. Automobiles, for example, produce NOx when they burn gasoline. But a lot of NOx comes from coal-burning power plants, so the Clean Coal Technology Program developed new ways to reduce this pollutant. One of the best ways to reduce nitrogen oxides is to prevent it from forming in the first place. Scientists have found ways to burn coal (and other fuels) in burners where there is more fuel than air in the hottest combustion chambers. Under these conditions, most of the oxygen in air combines with the fuel, rather than with the nitrogen. The burning mixture is then sent into a second combustion chamber where a similar process is repeated until all the fuel is burned. This
concept is called "staged combustion" because coal is burned in
stages. A new family of coal burners called "low-NOx burners" has been
developed using this way of burning coal. These burners can reduce the amount of
nitrogen oxides released into the
air by more than half. Today, because of research and the Clean
Coal Technology Program, more than half of all the large coal-burning
boilers in the There is also a family of new technologies that work like "scubbers" by cleaning NOx from the flue gases (the smoke) of coal burners. Some of these devices use special chemicals called "catalysts" that break apart the NOx into non-polluting gases. Although these devices are more expensive than "low-NOx burners," they can remove up to 90 percent of NOx pollutants. But in the future, there may be an even cleaner way to burn coal in a power plant. Or maybe, there may be a way that doesn't burn the coal at all. Fluidized Bed Boilers, a Bed for Burning Coal? It
was a wet, chilly day in It was a small coal burner by today's standards, but large enough to provide heat and steam for much of the university campus. But the new boiler built beside the campus tennis courts was unlike most other boilers in the world.
It was called a "fluidized bed boiler." In a typical coal boiler, coal would be crushed into very fine particles, blown into the boiler, and ignited to form a long, lazy flame. Or in other types of boilers, the burning coal would rest on grates. But in a "fluidized bed boiler," crushed coal particles float inside the boiler, suspended on upward-blowing jets of air. The red-hot mass of floating coal — called the "bed" — would bubble and tumble around like boiling lava inside a volcano. Scientists call this being "fluidized." That's how the name "fluidized bed boiler" came about. Why does a "fluidized bed boiler" burn coal cleaner? There are two major reasons. One, the tumbling action allows limestone to be mixed in with the coal. Remember limestone from a couple of pages ago? Limestone is a sulfur sponge — it absorbs sulfur pollutants. As coal burns in a fluidized bed boiler, it releases sulfur. But just as rapidly, the limestone tumbling around beside the coal captures the sulfur. A chemical reaction occurs, and the sulfur gases are changed into a dry powder that can be removed from the boiler. (This dry powder — called calcium sulfate — can be processed into the wallboard we use for building walls inside our houses.) The second reason a fluidized bed boiler burns cleaner is that it burns "cooler." Now, cooler in this sense is still pretty hot — about 1400 degrees F. But older coal boilers operate at temperatures nearly twice that (almost 3000 degrees F). Remember NOx from the page before (go back)? NOx forms when a fuel burns hot enough to break apart nitrogen molecules in the air and cause the nitrogen atoms to join with oxygen atoms. But 1400 degrees isn't hot enough for that to happen, so very little NOx forms in a fluidized bed boiler. The result is that a fluidized bed boiler can burn very dirty coal and remove 90% or more of the sulfur and nitrogen pollutants while the coal is burning. Fluidized bed boilers can also burn just about anything else — wood, ground-up railroad ties, even soggy coffee grounds. Today,
fluidized bed boilers are
operating or being built that are 10 to 20 times larger than the small unit
built almost 20 years ago at Georgetown University. There are more than 300 of
these boilers around this country and the world. The Clean
Coal Technology Program helped test these boilers in A new type of fluidized bed boiler makes a major improvement in the basic system. It encases the entire boiler inside a large pressure vessel, much like the pressure cooker used in homes for canning fruits and vegetables — except the ones used in power plants are the size of a small house! Burning coal in a "pressurized fluidized bed boiler" produces a high-pressure stream of combustion gases that can spin a gas turbine to make electricity, then boil water for a steam turbine — two sources of electricity from the same fuel! A "pressurized fluidized bed boiler" is a more efficient way to burn coal. In fact, future boilers using this system will be able to generate 50% more electricity from coal than a regular power plant from the same amount of coal. That's like getting 3 units of power when you used to get only 2. Because it uses less fuel to produce the same amount of power, a more efficient "pressurized fluidized bed boiler" will reduce the amount of carbon dioxide (a greenhouse gas) released from coal-burning power plants. "Pressurized fluidized bed boilers" are one of the newest ways to burn coal cleanly. But there is another new way that doesn't actually burn the coal at all. Don't think of coal as a solid black rock. Think of it as a mass of atoms. Most of the atoms are carbon. A few are hydrogen. And there are some others, like sulfur and nitrogen, mixed in. Chemists can take this mass of atoms, break it apart, and make new substances — like gas!
How do you break apart the atoms of coal? You may think it would take a sledgehammer, but actually all it takes is water and heat. Heat coal hot enough inside a big metal vessel, blast it with steam (the water), and it breaks apart. Into what? The carbon atoms join with oxygen that is in the air (or pure oxygen can be injected into the vessel). The hydrogen atoms join with each other. The result is a mixture of carbon monoxide and hydrogen — a gas. Now, what do you do with the gas? You can burn it and uses the hot combustion gases to spin a gas turbine to generate electricity. The exhaust gases coming out of the gas turbine are hot enough to boil water to make steam that can spin another type of turbine to generate even more electricity. But why go to all the trouble to turn the coal into gas if all you are going to do is burn it? A major reason is that the impurities in coal — like sulfur, nitrogen and many other trace elements — can be almost entirely filtered out when coal is changed into a gas (a process called gasification). In fact, scientists have ways to remove 99.9% of the sulfur and small dirt particles from the coal gas. Gasifying coal or "Coal Gasification" is one of the best ways to clean pollutants out of coal. Another reason is that the coal gases, which is called "Synthesis Gas" and is made up by carbon monoxide and hydrogen — don't have to be burned. They can also be used as valuable chemicals. Scientists have developed chemical reactions that turn carbon monoxide and hydrogen into everything from liquid fuels for cars and trucks to plastic toothbrushes! Today,
in Coal gasification could be one of the most promising ways to use coal in the future to generate electricity and other valuable products. Yet, it is only one of an entirely new family of energy processes called "Clean Coal Technologies" — technologies that can make fossil fuels future fuels.
Fluidized
beds suspend solid fuels on upward-blowing jets of air during the combustion
process. The result is a turbulent mixing of gas and solids. The tumbling
action, much like a bubbling fluid, provides more effective chemical reactions
and heat transfer. Fluidized bed
combustion evolved from efforts to find a combustion process able to control
pollutant emissions without external emission controls (such as scrubbers). The
technology burns fuel at temperatures of 1,400 to 1,700 degrees F, well below
the threshold where nitrogen oxides form (at approximately 2,500 degrees F, the
nitrogen and oxygen atoms in the combustion air combine to form nitrogen oxide
pollutants).
Technology/Project
Description Next, a hydrolysis reactor converts carbonyl sulfide (COS)
in the raw Synthesis Gas to hydrogen sulfide (H2S) that is more easily
removed. The raw Synthesis Gas is then further cooled before entering a conventional
amine sulfur removal system and sulfuric acid plant (SAP). The cleaned gases are
then reheated and routed to a combined-cycle system for power generation. The
gas turbine generates 192 MWe. Thermal NOx is controlled to 0.7 lb/MWh by
injecting nitrogen. A steam turbine uses steam produced by cooling the Synthesis
Gas and superheated with the gas turbine exhaust gases in the Heat
Recovery Steam Generator to produce an
additional 123 MWe. The air separation unit consumes 55 MW and auxiliaries
require 10 MW, resulting in 250 MWe net power to the grid. The plant heat rate
is 9,650 Btu/kWh (HHV). Integrated Gasification Combined Cycle
Process Flow Diagram Results
Summary Environmental
The Integrated Gasification Combined Cycle
plant removed over 97% of
feedstock sulfur when operated on low-cost, high-sulfur coal, petroleum
coke, and coal/petroleum coke
blends.
Typical NOx
emissions were 0.7 lb/MWh, which were below the permitted limit of 0.9 lb/MWh
and far below New Source Performance Standard (NSPS) NOx levels of 1.6 lb/MWh
for electric utility units.
The CO emissions were permitted at 99 lb/hr and averaged 7.2 lb/hr; volatile
organic compound (VOC) emissions were negligible; and mercury emissions (on
coal) without controls were half the potential release based on mercury levels
in the coal. Operational
The PPS
combustion turbine logged 34,800 hours over the 5-year demonstration, of which
28,500 hours were
synthesis
gas-fired;
synthesis
gas
firing produced over 8.6 million MWh of
electricity.
The
gasifier on-stream factor steadily increased, reaching 70–80% after 2˝ years;
overall PPS availability, with distillate fuel as backup, averaged 90% after 1˝
years.
Carbon
conversion was lower than expected—in the low to mid 90% range versus the
expected 97.5–98%. This rendered the ASU design capacity inadequate because of
a need to recycle flyash, lowering PPS output to 235 MWe net, and required
doubling the capacity of the solids handling system.
Refractory
liner life was problematic during the demonstration largely due to frequent fuel
changes and attendant undesirable fluctuations in operating conditions, but a
coal/petroleum coke blend was identified to eliminate the problem in commercial
service.
In the
high-temperature heat recovery systems downstream of the gasifier, the radiant
syngas cooler seals underwent design changes or corrections for fabrication
defects; convective syngas coolers required geometric improvements to reduce
plugging; and raw gas/ clean gas heat exchangers required removal due to stress
corrosion.
A COS hydrolysis unit had
to be added to meet sulfur- reduction targets and an ion exchange unit added to
prevent buildup of heat-stable salts in the MDEA unit.
"Y” strainers and a 10 micron filter system proved critical to turbine
protection from pipe-scale during start-ups. Economic
A capital
cost of $1,650/kW (2001$) was estimated for a new 250 MWe (net) Integrated Gasification Combined Cycle
plant based on the PPS configuration incorporating lessons learned. A capital
cost of $1,300/kW (2001$) was estimated for a new plant that allowed for
benefits derived from economies of scale, technology improvements, and
replication of proven configurations to eliminate costly reinvention. Project
Summary This
project has been the recipient of numerous environmental and technological
achievement awards. These include the Ecological Society of America Corporate
Award, the Florida Audubon Society Corporate Award, and Power magazine's 1997
Power Plant of the Year Award. The plant was inducted into Power magazine's
Power Plant Hall of Fame. Over
the 5-year demonstration period, the company carried out a systematic campaign
to address and resolve the usual technical issues accompanying first-of-a-kind
plants. The company showed through the demonstration that a modest-sized
utility, with expertise in coal
fired power plants, can build and operate an Integrated Gasification Combined Cycle
plant. Environmental
Performance Permit
limits on NOx emissions during the PPS demonstration period were 25 parts per
million by volume on a dry basis (ppmvd) corrected to 15% O2. This
value equated to 35 parts per million (ppm) as measured at the stack by a
continuous emissions monitor (CEM). The permit limit is also equivalent to about
220 lb/hr NOx or 0.9 lb/MWh. Typical Polk Integrated Gasification Combined Cycle
NOx emissions were about 0.7 lb/MWh, or below 30 ppm by CEM. These emission
rates are a fraction of those from conventional coal
fired power plants equipped
with low-NOx combustion systems. For comparison, the NSPS for electric utility
units is 1.6 lb/MWh, regardless of fuel type. The
PM emissions from the Integrated Gasification Combined Cycle
are typically less
than 0.04 lb/MWh, which is approximately 5% of those from conventional
coal-fired plants equipped with electrostatic precipitators. These near-zero
emissions are the result of the concentrated, low-volume raw synthesis
gas flow and
application of intensive liquid scrubbing and no less than 15 stages of
liquid-gas contact. The CO emissions, permitted at 99 lb/hr, averaged 7.2 lb/hr. The VOC emissions, permitted at 3 lb/hr, averaged 0.02 lb/hr. Mercury emissions were not regulated,
but measurements taken showed that the Integrated Gasification Combined Cycle
removed about half of the mercury constituent in coal feedstocks. Operational
Performance The
gasifier and associated systems involved in producing clean synthesis
gas showed steady
improvement in the unit's in-service (on-stream) factor over the first four
years, reaching 70–80% after 2˝ years, before suffering a setback in the
fifth and final demonstration year. The fifth year was not considered
representative. It included a lengthy planned outage to deal with gasifier
refractory damage incurred by frequent feedstock changes, followed by a rare ASU
forced outage and the one-time removal of soot-blower lances. The on-stream
factor is the percentage of time the gasifier and associated systems were in
operation over the total number of hours in the year of operation. The
availability of the combined-cycle power block to produce electricity from
either synthesis
gas
or distillate was approximately 90% over the last four years of
the demonstration. The company also calculated on-peak availability because of
the importance of the plant in meeting peak summer demand. The peak
availabilities for 2000 and 2001 were 94.9% and 97.7%, respectively. The
following is a summary of the highlights of the technical issues that emerged
during the demonstration. Most of the issues were resolved, and others served as
lessons learned to improve the technology for future plants. Together, the
issues served to advance the technology closer to widespread commercial
deployment. Lower-than-anticipated
carbon conversion in the gasifier had major cost and performance impacts that
reverberated through the Integrated Gasification Combined Cycle
system. Carbon
conversions of 97.5– 98% per pass were expected based on performance of
smaller gasifiers. The PPS gasifier achieved per pass carbon conversion in the
low- to mid- 90% range. Even
at design capacity, the ASU could not deliver enough air to meet the total
gasifier oxygen requirements given the unexpectedly low carbon conversion and
the resulting need to recycle flyash (which reduced fuel quality). Moreover, the
company desired the flexibility to process low-quality fuels. Essentially
all carbon steel parts in contact with the slurry feedstock had to be replaced
or coated with corrosion-resistant materials, and high-wear areas had to be
hardened. The
company evaluated numerous modifications to the slurry feed injectors in an
attempt to resolve the carbon conversion issue. Only marginal improvement
resulted. A
two-year gasifier refractory liner life commercial goal established for the PPS
was not met during the demonstration period primarily because of frequent fuel
changes. The fuel changes introduced risk in operational settings and
less-than-optimal operating conditions as adjustments were made. Also, the high
number of start-up and shutdown cycles experienced during the demonstration
period accelerated refractory spalling. The
company carried out extensive feedstock testing during the demonstration with
refractory life being a prime consideration. Testing showed that a blend of 45%
Black Beauty and Mina Norte coals with 55% petroleum coke provided excellent
cost and performance characteristics and the potential for long refractory liner
life. Contributing
to the refractory degradation was the inability to directly measure gasifier
temperatures on a realtime basis. Thermocouples failed to survive the gasifier
flow path. Gasifier temperature measurements primarily relied on “inferential
measurement” based on methane formation. Monitoring and control of gasifier
temperature also is critical for control of slag viscosity and flyash volume. All
radiant synthesis gas cooler seals eventually failed due to either fabrication defects
or design flaws, all of which were corrected. Corrections included removal of
all but 8 of the 122 soot-blower lances. Only four lances are used as sootblowers.
The other four serve as purge points for injection of N2 during
start-up and shutdown. The
CSC fire-tube heat exchanger was a source of frequent plugging and forced
outages through 1999. The plugging primarily occurred at the CSC tubesheet
inlet. In 1999, significant geometric improvements dramatically reduced plugging
by more than half. Although not eliminated, CSC pluggage is deemed manageable. The
gasifier's lower-than-expected carbon conversion required twice as much fly ash
and associated black water to be processed as originally designed. This
increased volume essentially overwhelmed the solids handling system, precluded
slag sales, and posed significant disposal costs. To resolve these issues, the
company (1) doubled the capacity of the fines (predominately flyash) handling
system; (2) provided the capability to recycle 100% of the settler bottoms
flyash to the gasifier slurry preparation system; (3) used condensate water
instead of grey water in the slag removal system and stripped the ammonia from
that condensate water; and (4) added a drag conveyor and screen to de-water and
separate the fly-ash from the slag. With these changes, operation on 100% coal
enabled sales of the slag while recycling 100% of the settler bottom flyash and
generating 235 MWe (net). The company's future plans include increasing ASU
capacity to provide enough oxygen to compensate for added fuel required to boost
output to the rated capacity of 250 MWe year round. In
the original Integrated Gasification Combined Cycle
design, heat exchangers were
incorporated downstream of the CSC to recover process heat by warming clean gas
and diluent N2 going to the combustion turbine. Flyash deposits from
the raw synthesis gas resulted in stress corrosion, cracking of the tubes, and turbine
blade damage. These heat exchangers were removed because the heat recovery, less
than 1.7% of the fuel's heating value, did not warrant the cost of redesign. The
company incorporated a COS hydrolysis system in 1999. An ion exchange system was
subsequently added to control a high rate of heat-stable salt formation
resulting from COS hydrolysis. The
only major power block forced outages during synthesis
gas- based operation resulted
from failures of the raw gas/ clean gas heat exchanger (since removed) in the
absence of protective “Y” strainers. The “Y” strainers had been removed
for repair. “Y” strainers subsequently proved critical for start-ups because
of the release of large volumes of pipe scale. To increase turbine protection
and reduce “Y” strainer cleaning, a 10 micron final synthesis
gas filter was
installed upstream of the synthesis gas
strainers. This filter was sized to catch a
year's worth of pipe scale. Economic
Performance Commercial
Applications As to availability, the company noted that: (1) the PPS gasifier availability is lower than can be expected for subsequent Integrated Gasification Combined Cycle plants incorporating lessons learned; (2) overall PPS availability, including operation on backup fuel, is very high; and (3) the PPS experience showed that availability can be effectively managed.
What is "Decentralized Energy"? Decentralized Energy is the opposite of "centralized energy." Decentralized Energy energy generates the power and energy that a residential, commercial or industrial customer needs, onsite. Examples of decentralized energy production are solar energy systems and solar trigeneration energy systems. Today's electric utility industry was "born" in the 1930's, when fossil fuel prices were cheap, and the cost of wheeling the electricity via transmission power lines, was also cheap. "Central" power plants could be located hundreds of miles from the load centers, or cities, where the electricity was needed. These extreme inefficiencies and cheap fossil fuel prices have added a considerable economic and environmental burden to the consumers and the planet. Centralized energy is found in the form of electric utility companies that generate power from "central" power plants. Central power plants are highly inefficient, averaging only 33% net system efficiency. This means that the power coming to your home or business - including the line losses and transmission inefficiencies of moving the power - has lost 75% to as much as 80% energy it started with at the "central" power plant. These losses and inefficiencies translate into significantly increased energy expenses by the residential and commercial consumers.
How we make and distribute electricity is changing! The electric power generation, transmission and distribution system (the electric "grid") is changing and evolving from the electric grid of the 19th and 20th centuries, which was inefficient, highly-polluting, very expensive and “dumb.”
The "old" way of generating and distributing
energy resembles this slide:
Some customers will choose to dis-connect from the grid entirely. (Electric grid represented by the small light blue circles in the slide below.)
Typical "central" power plants and the electric utility companies that own them will either be shut-down, closed or go out of business due to one or more of the following: failed business model, inordinate expenses related to central power plants that are inefficient, excessive pollution/emissions, high costs, continued reliance on the use of fossil fuels to generate energy, and the failure to provide efficient, carbon free energy and pollution free power. Carbon free energy and pollution free power reduces our dependence on foreign oil and makes us Energy Independent while reducing and eliminating Greenhouse Gas Emissions.
For more information, call us at: 832 - 758 - 0027 * Some of the above information from the Department of Energy website with permission.
Greenhouse Gas
Emissions Linked to
Photo courtesy of Alaska Image Library. U.S. Fish and Wildlife Service
“spending hundreds and hundreds and hundreds of billions of dollars every year for oil, much of it from the Middle East, is just about the single stupidest thing that modern society could possibly do. It’s very difficult to think of anything more idiotic then that.” R. James Woolsey, Jr., former Director of the CIA
The Renewable Energy Institute (REI) does not take a stand in the debate on global warming, and if there is, is it "anthropogenic" and not caused by the sun, sun spots, or the sun's normal cycles. Or, is global warming and climate change caused by the water vapor in the atmosphere? At the Renewable Energy Institute, we are waiting for the "true" scientists, doing the "real" research, to provide the science and answers, and not the phony scientists who are following the politically-motivated and profit-driven agendas of the United Nations and many countries and government leaders. These phony scientists are not interested in conducting real scientific research. Their very livelihoods are dependent on the government grants to fund their phony research. This "political-interference" by governments, governmental agencies, and so-called "leaders" that hand out billions of dollars for these phony scientists to conduct climate science and research, expect the conclusions of the "research" to be tainted, skewed, flawed to support anthropogenic global warming, or climate change. Should these scientists accurately conclude in their research that they find no evidence of anthropogenic climate change or global warming, they are summarily dismissed, and black-balled from their communities and colleagues, and never again receive funding or grants. This "politically-driven" process of providing funding and grants for real scientific research must stop. In the meantime, far more harm is being done to our planet as well as to people and plants and animals, particularly fish, from the mercury emissions from coal fired power plants than from the coal fired power plants' greenhouse gas emissions. We surmise that if any polar bears have died as a result of an environmental problem, it was more likely from the high levels of mercury in their food chain, than from greenhouse gas emissions. The Renewable Energy Institute is supporting and advancing renewable energy technologies, as well as reducing and eliminating greenhouse gas emissions and the fossil-fuel problems related to America's oil addiction and ending our dependence on foreign oil. The renewable energy technologies we support are already deemed to be economic, viable and practical. Solutions such as Solar Trigeneration energy systems (see www.SolarTrigeneration.com for more information) for any kind of facility or building - office buildings, shopping centers, data centers, university campuses, etc. Since 2003, a Solar Trigeneration energy system has been providing 100% of the power and energy for a 5,300 sq. ft. office building near downtown Los Angeles, and doing so without any connection to the electric grid, whether its 12 noon or 12 midnite! The Renewable Energy Institute is also involved in research and advocacy of "Net Zero Energy" (see: www.NetZeroEnergy.com for more information) and "Net Zero Energy Buildings" (see: www.NetZeroEnergyBuildings.com for more information). Net Zero Energy Buildings generate as much (or more) energy than they use, and export their excess power to the grid. Climate Change, Global Warming or Global Cooling? The past 10 years indicates the opposite, that there has been a moderation of "global warming" and that global cooling has taken place. "Climate change" is always taking place, from one day to the next, and one week to the next, as well as one year to the next. Climate change is a dynamic process. The REI would request that the researchers and scientists stay out of politics, and not be politicians, and that the politicians would stay out of the way of the scientists and researchers, and let them do their work, and that the politicians not pretend to be scientists. Everybody, scientists and politicians, just do your job so that we can come up with the scientific answers that form the basis of policy. In the meantime, as there may still be 30 years of research before there are conclusive answers. Can we "risk" 30 years of our children and our children's future, if there is a link between climate change and greenhouse gas emissions? Simultaneously, there is a finite amount of petroleum, and many scientists and engineers believe we have well into Hubbert's "peak oil" analysis, that espouses that when 50% of domestic crude oil production has been reached, that there will be such significant upward demand on prices of the limited supplies of oil production, that the U.S. economy will experience severe economic, social, and political turmoil. Hubbert's Peak Oil predictions were "right on" and this is validated as the U.S. in the early 1970's produced about 60% of its' oil demand and imported 40%. That equation has flipped since then, because our domestic oil production has been on the decline since 1970, so now, due to our declining domestic oil production, we have to import 60% of our oil supplies, to meet our country's oil/energy demands. How severe our economic calamity and next "oil shock" will depend upon a number of factors, including when this occurs, as well as the following: 1. the dependence of the individual country upon its own crude oil production to meet its energy needs and to subsidize consumer imports; 2. the rate of relative decline in crude oil production; 3. the degree of difficulty encountered in replacing missing energy inputs; 4.
the degree to which our country had prepared in advance for this inevitable geological
and economic calamity. Iran: Their peak crude oil production occurred in 1974; They had their islamic revolution 1979 that overturned government and replaced it with radical islam. Soviet
Union: Their peak crude oil production
was in 1989; what happened next? Iraq: Iraq's crude oil production was in 1989; they then invaded Kuwait (for their oil) in 1991. Using Mr. Hubbert's predictions, that beginning around 2000 we would see peak (global) oil production, then, if the country's not weaning themselves off of their oil addiction, and had not begun making the switch to renewable energy, that the negative economic and political calamities would soon follow, including ever-increasing prices of energy that is from fossil fuels. Now
is the time to begin weaning ourselves off of fossil fuels and making the
transition to and increasing the use of renewable energy. If
you don't believe in climate change, or global warming, GREAT! Join us in the
switch to renewable energy and a fossil-free economy!
America's "Clear and Present Danger" America
Has INCREASED its' Dependence on Foreign America
is even more "addicted" to foreign oil today, than we were in 1973 -
1974 when OPEC, Saudi Arabia and other suppliers from the Middle-East
stopped selling us their fossil fuels, and created a significant blow to our
economy.
According to the CIA Fact Book, Every Day, the U.S.: PRODUCES:
7,460,000 bbls of oil (within its borders) CONSUMES:
20,800,000 bbls of oil
Simply put, about 65% of the gasoline in your car's gas tank, comes from a foreign country. EVERY day, the U.S. must IMPORT over 13 million bbls of oil from foreign countries and foreign suppliers to meet demand.
This is NOT acceptable. America needs to quickly transition to Energy Independence. Renewable Energy is the Only Way America Can Achieve Energy Independence. Million of new and sustainable American jobs would be created here at home, if we would end our addiction to foreign fossil fuels, and quickly transition to an economy based on renewable energy and renewable fuels, produced here in the U.S.A. The good news is that today, America already has all of the Renewable Energy Resources and Renewable Energy Technologies needed to make American Energy Independence a reality. According to Monty Goodell, Founder and Chairman of the Renewable Energy Institute, "our increased dependence and reliance on foreign energy supplies represents a Clear and Present Danger to our national security, our economy, and the lives and livelihood of every American. Energy - including the energy we use from imported fossil fuels, is the very "lifeblood" of the American economy as it is for every industrialized country. An economy dies without it's lifeblood of energy. This Clear and Present Danger we face is far more serious than the problems related to greenhouse gas emissions. And while greenhouse gas emissions are very serious issue, in the long-term, pales in comparison to America's vital national security interests and America's economic stability in the short term. For this reason alone, America needs to transition away from its addiction to foreign energy supplies. And America's abundant renewable energy resources such as the energy we receive from the sun, and renewable energy technologies such as concentrated solar power (CSP) plants - can supply 100% of America's power requirements with a concentrating solar power plant measuring 75 miles by 75 miles, located in the Southwest U.S. By generating America's power from concentrating solar power plants, America resolves its' short-term Clear and Present Danger as it relates to importing its energy from foreign countries, and the long-term problems relating to greenhouse gas emissions." Continuing, Mr. Goodell states that "too many Americans have forgotten what happened to us in 1973, when the Arabs and OPEC brought the United States economy to a screeching halt during the OPEC Oil Embargo. This happened because they (mainly the country of Saudi Arabia) disagreed with our foreign policy and is the reason why they "turned off the tap" of our need for their oil supplies. When Saudi Arabia and OPEC stopped the vital flow of oil to our country in 1973, they caused an "oil shock" that severely and negatively impacted our economy. Mr. Goodell's question for us to ponder is, "do these countries who sell us 60% of our daily energy requirements, like us and our foreign policy, or might they leverage our addiction to their fossil fuels, and turn off the tap to make us adjust or revise our foreign policy?? Like any addict, America's foreign policy may be held hostage to its addiction, and in this case, our addiction to foreign oil, may over-ride our national interests." Have
American's forgotten the gas shortages and long lines at "Apparently so." Mr. Goodell states that "in 1973, America was 'addicted' and 'over the barrel' of foreign oil to the amount of 40%. Forty percent of our energy 'needs' in 1973 came from countries - many of which didn't like us then, and I'm afraid, many of them still don't. The difference between 1973 and today - is that today we receive 50% MORE foreign oil now than we did in 1973. And now we know about the problems relating to greenhouse gas emissions that we didn't know then. America needs to change course, and change course now, in terms of its' energy supplies and how we keep America's economy strong, without the threat of being held hostage to a middle-east tyrant or regime, that could once again, turn on us, and turn off our supply of foreign oil." Remember
????
"Let me Repeat.... That was 1973 when we imported 40% of our daily energy requirements in the form of crude oil from overseas, and from foreign countries - and many of these from countries that don't like us. Today, over 35 years later, America has yet to learn the lesson. We cannot continue our reliance on energy from foreign countries that supply us with 60% of the crude oil that our refineries use as a feedstock for producing gasoline and diesel fuel for our cars and trucks comes from overseas. America is "over the barrel" and it's not our barrel, but the barrels of oil that we are addicted by and owned by other countries. Why have we not learned the lessons we needed to learn in 1973 when we were cut-off from the vital energy supplies we need? Countries like China, are growing rapidly, and have an insatiable need for crude oil. China, with their booming economy, is increasingly growing in its clout and control over international supplies of crude oil - whether they do this through their ability to buy as much oil as they need on a daily basis, or whether they simply but American drilling rigs, technology, and explore and produce oil and gas from their own fields. China, is buying large amounts of oil for their country, and causing upward pricing on declining supplies. What happens if Russia, with all of their oil and natural gas, along with China and Venezuela, with or without the help of OPEC, decided to NOT sell oil to us???? To be sure, greenhouse gas emissions are a problem, and to some, greenhouse gas emissions are also a Clear and Present Danger, but not to the extent that it presents an imminent Clear and Present Danger. America's reliance for 60% of our energy "needs" coming from foreign suppliers is un-acceptable. The "driver" to get America to begin reducing and eliminating fossil fuel use should be our nation's national security and the welfare and safety of its citizens. And this can all begin with developing and investing in our own renewable energy resources and renewable energy technologies, let's start by putting solar on every rooftop that has a clear and unobstructed view of the Southern sky. See www.RooftopPV.com or www.DistributedPV.com for more information. Let's create incentives begin with adopting a national "Feed In Tariff" as Germany did in 1990. America,
we simply do NOT have the luxury of time on our hands. We need to end our
dependence and reliance on foreign fossil fuels, especially from countries that
don't like us! We need to rapidly begin expanding renewable energy
resources and renewable
energy technologies from our vast and abundant renewable energy resources,
such as; solar, solar energy systems, solar cogeneration, solar trigeneration,
"solar on every roof," waste to energy, waste to fuel, biomass
gasification, B100 Biodiesel, Biomethane, Synthesis Gas, geothermal, E100
Ethanol (from sugar cane and NOT from corn), and wind, where it makes economic
sense."
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We support the Renewable Energy Institute by donating a portion of our profits to the Renewable Energy Institute in their efforts to reduce fossil fuel use through renewable energy and their goals to end pollution from Carbon Dioxide Emissions and Greenhouse Gas Emissions. The Renewable Energy Institute is "Changing The Way The World Makes and Uses Energy by Providing Research & Development, Funding and Resources That Create Pollution Free Power, Carbon Free Energy & Renewable Energy Technologies."
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