Coal

The pilot-scale project at Georgia Power’s Plant Yates near Newnan, Ga.—the first step in one of the industry’s largest demonstrations of a start-to-finish coal-fired power plant carbon capture and storage system—reached a significant milestone this September, capturing the greenhouse gas for the first time.

In August, researchers from the University of Cincinnati who are working on creating an artificial foam that could absorb carbon dioxide (CO₂) from the flue gas at power plants and convert it into biofuel won the grand prize at the 2010 Earth Awards in London.

Steel piping systems are widely used at coal-fired power plants for a variety of purposes, including the conveying of coal ash slurry to nearby settling ponds, the transfer of limestone slurry to absorber spray towers for removal of SO₂ and dilute hydrochloric acid from flue gases, and for transporting away the calcium sulfate by-product of the flue gas desulfurization process.

Responding to looming federal regulations to reduce power plant pollution, the Tennessee Valley Authority’s board signed off on a proposal to shut down 1,000 MW of older coal-fired generation and replace it with an equal amount of natural gas capacity while also pursuing 1,900 MW of demand response and energy efficiency programs and adding 1,140 MW of new nuclear generation by 2015.

An Environmental Protection Agency plan to tighten emission limits for new and existing industrial boilers has sparked alarmed protests from the biomass generation industry and electric utilities, who say the proposed regulations are so onerous they threaten to shut down existing biomass power plants and already are chilling deployment of new facilities.

The conventional and oft-repeated truth is that wind generation directly reduces carbon emissions. Challenging the conventional wisdom has drawn much criticism from wind proponents, but the latest research has shown that wind has had, and will continue to have, negligible impact on the nation’s carbon emissions. The data are convincing and can no longer be ignored.

Wind electricity production must displace some existing generation. However, its relentless variability imposes daunting challenges for wind integration. Clever engineering schemes can mask the problem, but the data show that wind generation has and will continue to reduce carbon by negligible amounts, but at great expense.

If you want the most accurate test results, it’s worth the extra effort to take isokinetic coal samples from coal pipes when collecting fuel and air measurements. Together, the data collected will allow more accurate balancing of coal pipes, measure fuel fineness, and improve the combustion efficiency of your steam generator.

Pending Environmental Protection Agency regulations to slash U.S. power plant emissions likely will lead to the closure of nearly 18% of the nation’s coal-fired generation capacity, trim demand for steam coal by 15% to 31% and boost demand for natural gas by 8% to 16%, a new Credit Suisse analysis concludes.

In the heart of corn country, Archer Daniels Midland is using seed corn that is no longer suitable for planting, along with coal, to power its 180-MW Clinton cogeneration plant. The cogeneration plant, which began operations in 2008, supports ADM’s Clinton corn processing plant, one of the largest corn wet mills in the world. It also supports ADM’s facility that produces renewable plastic from corn sugar. Firing up to 20% biomass along with coal, the new cogeneration plant is capable of providing 100% of the steam and electrical power needs of both facilities.

Constellation Energy Constellation Energy recently completed a series of air quality upgrades on both units at its Brandon Shores Generating Station that included flue gas desulfurization (FGD), baghouse, SO₃ control, and mercury reduction by activated carbon injection. The plant’s unique arrangement required long duct runs to the air quality system and a mile-long conveyor for moving barge-delivered limestone to the plant. Treated municipal wastewater was used as wet FGD supply water, and effluent treatment included first-of-its-kind nitrogen removal before discharge to the Chesapeake Bay watershed.

The 1,456-MW Brunner Island coal-fired plant has implemented advanced environmental improvements in order to be a good neighbor to the residents of south central Pennsylvania. For example, between 2006 and 2010, PPL invested more than $860 million in pollution control upgrades for air, water, and solid waste treatment at the facility.

Owner/operator: Mirant Corp. Dickerson Generating Station, a 50-year-old facility servicing Maryland and Washington, D.C., was recently upgraded with a flue gas desulfurization system and a unique draft system that allows an electrostatic precipitator and a baghouse to share flue gas cleanup chores on each unit. In addition, state-of-the-art equipment monitoring and diagnostics keep plant reliability high for this baseload unit.

Unit 2 at J-POWER’s Isogo Thermal Power Station entered commercial service in July 2009. The 600-MW ultrasupercritical unit joins an earlier, similar plant built in 2002. Together, these two new plants replaced 1960s-vintage coal-fired plants and doubled power generation from the small project site. In addition, the new unit improves the plant’s gross thermal efficiency to about 45% while reducing air emissions to those of a gas-fired combined-cycle plant.

Adding two 615-MW supercritical pulverized coal units to the 1,135-MW Oak Creek Power Plant is part of We Energies’ ongoing master plan to “Power the Future” of Wisconsin well into the 21st century. The new Elm Road Unit 1 went into service in February, and Unit 2 is expected to start operations during the fourth quarter of 2010. With operations marked by high efficiency and low emissions, these new units will provide large amounts of cleaner energy to the Great Lakes area.

Located in a semi-arid region, this “Texas tough” coal-fired power plant uses a number of smart practices to increase water-use efficiency. For example, a pipeline was constructed to send blowdown water from nearby Plant X for treatment and recycling at the 1,080-MW Tolk Station, making both plants “zero-discharge” facilities. For its environmental stewardship and superior plant operations, the Powder River Coal Users’ Group named Tolk Station its 2010 Plant of the Year.

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Environmentalists renewed their attacks on coal-fired power development in 2010. At the same time, Congress dithered on cap-and-trade legislation while the Environmental Protection Agency marched forward rules to reduce carbon emissions from coal-fired power plants. Couple the regulatory uncertainty with lean economic times that have flatlined electricity demand growth plus low natural gas prices, and the result is predictable: New coal-fired plant construction is in the doldrums.

What’s in a name? Would coal ash labeled as “special” hazardous waste be as easily recycled as that labeled nonhazardous waste?

At the end of June, Xcel Energy fired up a demonstration project that integrates a 4-MW parabolic trough solar technology with an existing 44-MW coal-fired power plant.

Scuttling a high-profile “public nuisance” lawsuit, a federal appeals court has reversed a lower court ruling that required the Tennessee Valley Authority to accelerate plans to install pollution controls at four TVA coal-fired power plants to reduce the amount of pollution blowing into western North Carolina, saying the lower court decision could lead to other public nuisance suits that would wreak havoc on federal and state regulatory regimes for combating air pollution.

Saying they have “grave concerns” about the agency’s two-option proposal to regulate coal combustion ash, 31 members of the House Energy and Commerce Committee have urged the Environmental Protection Agency to continue to regulate coal ash as a non-hazardous waste, saying an EPA proposal to designate it as a “special” hazardous waste eligible for reuse would lead to costly and unnecessary management and disposal requirements.

An Environmental Protection Agency proposal to tighten sulfur dioxide and nitrogen oxides limits in 31 states and the District of Columbia to address transported air pollution fails to give utilities and state air regulators sufficient time to develop rules and install controls, according to American Electric Power Co. Officials from the EPA and New Jersey-based Public Service Enterprise Group said utilities already had begun making investments to cut emissions and they believed the agency’s compliance schedule could be met.

Many claim that wind generation is beneficial because it reduces pollution emissions and does not emit carbon dioxide. This isn’t necessarily the case. When wind is introduced into a generation system that uses carbon technologies to back up the wind, it actually reduces the energy efficiency of the carbon technologies.

Every power engineer must have a firm grasp of the rudiments of how fuel is processed to produce electricity in a power generation facility. With this article, we conclude our three-part series on the essentials of recovering heat from flue gas to dry and process coal, with the goal of improving overall plant operating efficiency.

Progress Energy has incorporated online combustion optimization/tuning to eliminate furnace reducing atmospheres at its Asheville Plant. The optimization project utilized individual burner airflow measurement and continuous burner coal flow measurement to adjust burner air/fuel ratios. The result: significantly improved boiler combustion.

With commercial operation of Madison Unit 3, Cleco Power now claims bragging rights for owning the largest 100% petroleum coke–fired circulating fluidized bed power plant in North America. For using readily available fuel in an environmentally attractive manner, adopting fuel-flexible combustion technology, balancing the utility’s generation portfolio, and adopting an innovative fuel-handling system design, Madison Unit 3 is the winner of POWER’s 2010 Marmaduke Award for excellence in operation and maintenance. The award is named for Marmaduke Surfaceblow, the fictional marine engineer and plant troubleshooter par excellence.

The amount of air leaking into the boiler envelope is difficult to estimate. Traditional methods of measuring oxygen at the furnace exit and economizer exit do not account for all types of air leakage. By using molar calculations and total airflow measurement, a good approximation of the total air in-leakage rates of a boiler can be quickly determined using station instruments.

Catalysts used in selective catalytic reduction (SCR) systems in utility boilers provide high NO_x removal efficiencies that routinely exceed 90%. A major co-benefit of applying SCR to coal-fired power plants is that the SCR catalyst also oxidizes the vapor phase mercury from an elemental form to a soluble ionic form, which can be readily captured in a downstream flue gas desulfurization process. Mitsubishi Heavy Industries and Cormetech have developed an advanced SCR catalyst technology with high mercury oxidation activity capable of achieving 95% oxidized mercury over a wide range of operating conditions.

The competitive push for more efficient power generation prompted the management of East Kentucky Power Cooperative’s Spurlock Station to provide training and to implement standardized work processes in order to achieve higher productivity. To that end, Spurlock’s management collaborated with salaried and hourly personnel to design and implement work process optimization. Two years later, their proactive, operations-driven culture is promoting continuous improvement at this facility.