Coal

The Energy Information Administraion has predicted that, as the economy gathers steam this year, rising demand for gasoline, crude oil, coal, and natural gas is expected to push up energy prices, aided by a projected boost in crude oil production.

It’s a digital world, and even aging power plants are experiencing the benefits of digital controls technologies. The following cover stories provide insight into the latest options and inspiration for your own plant controls projects.

In a typical steam power plant, the boiler feedwater (BFW) pump takes suction from the deaerator (DA) and discharges high-pressure water to the boiler through the feedwater heaters. During normal operation, the DA is supplied with steam turbine extraction steam to mix with and heat the feedwater.

The race is on to claim the title of "most efficient coal-fired power plant" on the planet. However, it’s tricky identifying finalists because of the widespread misuse of the term "efficiency" and all those nagging assumptions. Let’s first establish clear definitions and then identify the title contenders.

As equipment ages in fossil-fueled power plants, component wear leading to machinery failure increases as a result. Extending equipment life requires increased attention to maintenance, and one way to improve maintenance planning is to detect faults prior to failure so maintenance can be scheduled at the most cost-effective, opportune time. This type of strategy benefits from the use of additional sensors, and wireless ones can often be installed with the least time and cost.

News this past November that Australian company Cougar Energy had begun developing a pilot project to generate power from coal still underground has reignited interest in the 100-year-old alternative energy technology. The company’s planned A$8 million program — expected to be started in the first quarter of 2010 — will be conducted 10 kilometers south of Kingaroy, in southern Queensland. If it is successful, it could lead to the establishment of a 400-MW baseload power station, Cougar Energy officials say.

"It’s déjà vu all over again," said Yogi Berra. The Hall of Fame catcher could easily have been predicting the coming resurgence of natural gas – fired generation. Yes, a few more coal plants will be completed this year, but don’t expect any new plant announcements. A couple of nuclear plants may actually break ground, but don’t hold your breath. Many more wind turbines will dot the landscape as renewable portfolio standards dictate resource planning, but their peak generation contribution will be small. The dash for gas in the U.S. has begun, again.

The European carbon trading system experience suggests that North American generators should expect severely altered coal-fired power plant operating profiles if cap-and-trade legislation becomes law. In a groundbreaking study, Solomon Associates predicts the reduction in mean run time that North American generators should expect. The trends outlined in this study provide an overview of some of the broad challenges facing generators in moving to a carbon-constrained market environment.

With the eighth-largest economy in the world, Brazil has a clear need for power, but balancing supply and demand has proven tricky in recent decades. Even in a country where over 80% of generation capacity comes from renewables, planning for future capacity additions isn’t straightforward or easy.

The selective catalytic reduction system has become ubiquitous throughout the world of power plants. Emission control requirements are ever-more stringent, and the cost of excursions is becoming increasingly high. The key to staying under the regulators’ radar is precisely controlling the ammonia injected into the boiler. A new control strategy does precisely that.

Successful testing of a new refractory lining material developed by the Office of Fossil Energy’s National Energy Technology Laboratory (NETL) could lead to higher reliability and improved economics of gasification technology.

The U.S. Environmental Protection Agency has adopted final rules tightening emissions limits for coal preparation and processing plants and imposing new reporting requirements on those facilities.

In a major air regulatory development, the Environmental Protection Agency has agreed to issue rules by November 2011 to reduce mercury and other hazardous air pollution from coal- and oil-fired power plants under a settlement agreement resolving a lawsuit filed by a host of environmental organizations.

The Environmental Protection Agency has decided it will reconsider the 2008 ozone standards issued by the Bush administration, with the agency suggesting in a court that it would toughen the standards because it has concerns about whether standards “satisfy the requirements of the Clean Air Act.”

There are four approaches to measuring fly ash content and, therefore, the quality of fuel combustion in a boiler. Before choosing one, you should understand their relative levels of complexity and accuracy.

Erosion can significantly reduce the operational life of boiler components. Abrasion-resistant ceramic parts can be a sound alternative to expensive metallic parts when replacing boiler components.

When the Łagisza power plant began commercial operation in late June 2009, it marked the beginning of a new era in the evolution of circulating fluidized bed (CFB) technology. At the heart of this 460-MW plant is the world’s largest CFB boiler, which is also the world’s first once-through unit supercritical CFB boiler.

Assume, for the moment, that the U.S. Congress is unable to agree on legislation aimed at reducing carbon emissions from industry, vehicles, and power plants (the carrot approach). Further, assume that the Environmental Protection Agency (EPA) eventually promulgates rules that require power plants to reduce carbon emissions (the stick approach). Have you given any thought to the range of possible best available control technologies (BACT) that the EPA might require under the Clean Air Act (CAA)?

This September — a year after Vattenfall launched the world’s first oxyfuel pilot plant for carbon capture and sequestration (CCS) at the Schwarze Pumpe lignite-fired plant south of Berlin, Germany — three high-profile and long-awaited carbon capture tests started operation around the world.

The Environmental Protection Agency announced it plans to “revise” existing, decades-old guidelines for water discharges of toxic metals from fossil fuel-fired power plants, saying a recently concluded EPA study focused mostly on wastewater discharges from coal-fired power plants uncovered elevated levels of toxic pollutants.

In a major climate change rulemaking, the Environmental Protection Agency has issued final regulations that will require most large emitters of greenhouse gases in the U.S. to report their emissions beginning in 2010.

Can wind turbines actually reduce the amount of fossil fuels consumed? A Wall Street Journal analysis concludes that ERCOT utilities will begin to feel the squeeze in their profits this year and to expect the amount of fossil fuels used to generate electricity to be reduced.

Coal-fired power plants that fire low-cost coals or that are equipped with combustion modifications for NO_x controls are challenged with maintaining good combustion conditions while maximizing generation and minimizing emissions. In many cases, significant unit derates, availability losses, and an increase in unburned carbon levels can be attributed to poor combustion conditions that occur as a result of poorly controlled local air/fuel distribution within the boiler furnace. Fortunately, a new generation of combustion optimization technologies is available that uses burner air and fuel controls and spatially distributed combustion monitors to detect and correct local furnace air/fuel distribution imbalances.

The decision to retube a heat exchanger or condenser begins with understanding why tubes are failing. Only when the “why” is understood can the economic replacement tube material be selected. We explore the most common tube material failure mechanisms and then illustrate how to perform a proper life-cycle analysis for that new set of condenser tubes your plant so desperately needs. In sum, there are many reasons to consider getting the copper out of your condenser.

In another major legal victory for states pressing for controls on industry emissions of carbon dioxide, a federal appeals court has reversed a lower court decision and ruled that eight states and the city of New York City could bring “nuisance” suits against five coal-burning utilities to curb greenhouse gas discharges that the states claim are causing damage to their natural resources.

Boiler tube failures continue to be the leading cause of downtime for steam power plants. Is your boiler tube failure reduction program showing improvement when compared to programs at peer plants? The EUCG’s recent update of its boiler tube failure study can help you answer that question. The full study is available only to members, but this POWER exclusive presents many of the key results, which could help you improve the operation of your plant.

The expected renaissance for U.S. coal-fired generation has been more evolutionary than revolutionary: Less than half of the announced plants will likely progress to construction. However, the percentages for coal-fired plants aren’t significantly different from those for combined-cycle plants a decade ago, when dozens were ultimately canceled, leaving developers with warehouses full of unused gas turbines. The difference this time: The threat of carbon control legislation has moved many projects to the “wait and see” category.

Once pulverized coal flows have been measured, they can be balanced and optimized. Until then, tuning is simply guesswork. The right way to balance furnace fuel flows is to establish solid baseline performance by proper measurement of fuel flow, fineness, and velocity. Only then can all the coal pipes be accurately balanced and followed by a tune-up of the boiler controls.

Italy’s Enel said in August that it has successfully begun operating a power plant in Fusina, near Venice, in the Veneto region of Italy, that is fueled 100% by hydrogen. The industrial-sized plant’s building site was officially opened in April 2008, after which infrastructure and technology work was carried out on schedule. Initial testing of the turbine using methane gas was conducted in the spring of 2009, and now — after completion of the special pipeline — the plant has switched to 100% hydrogen fueling, Italy’s largest energy company said.