Coal

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.

Eliminate waste in coal, gas, or nuclear power plant construction through a holistic application of lean principles.

When it is completed, later this summer, the UK’s Drax Power Station biomass facility will become the largest dedicated cofiring project of its kind in the world. As U.S. coal-fired generators come under increasing pressure to cut emissions and take advantage of incentives to promote power generation from renewables, Drax offers an example of what is possible.

Fogging systems have been successfully used in the material-handling industry for more than 30 years to control explosive dust at transfer points. Today, fogging systems are an EPA Best Demonstrated Technology for subbituminous coal preparation plants.

At the opening ELECTRIC POWER 2010 plenary session, both the keynote speaker’s address and discussion among the Power Industry Executive Roundtable participants pointed to the renewed appeal of natural gas and proposed cap-and-trade legislation as being potential game-changers for the U.S. power industry.

The 2010 Powder River Basin Users’ Group (PRBCUG) commemorated its 10th anniversary with 354 registered members (210 of whom were from operating companies) for its three-and-a-half-day annual meeting in Baltimore this May. The meeting’s Grand Sponsor was Benetech and its Plant Professionals group.

In an unusual two-option proposal that drew clashing views from green groups and power plant operators, the Environmental Protection Agency has proposed regulating coal combustion ash either as a nonhazardous waste subject to tougher management and disposal requirements or as a "special" hazardous waste that would have similar controls but still be eligible for recycling and reuse in products such as Portland cement.

Less than 24 hours after the unveiling of sweeping Senate legislation to reduce U.S. greenhouse gas emissions, the Environmental Protection Agency released a final Clean Air Act rule that defines emission thresholds for greenhouse gas permitting requirements for power plants and other large stationary sources.

Facing a difficult uphill slog in a sharply polarized Senate, Sens. John Kerry and Joseph Lieberman have unveiled long-awaited draft climate change and energy legislation that includes billions of dollars in incentives for the nuclear, natural gas, and coal industries aimed at attracting enough bipartisan support to overcome an all-but-certain filibuster led by the Senate Republican leadership.

Boiler insulation practices have moved from using a single layer to a double layer of the same total thickness in recent years. However, this dual-layer trend has a downside: higher installation costs and the opportunity for contractors to cut corners when installing insulation. It’s time to return to using single-layer insulation on power boilers.

One of the primary challenges of reliably burning coal is managing the corrosion experienced by the furnace heat transfer surfaces. Fireside corrosion remains a leading cause of failure in superheater and reheater tubes. In Part I, we examined three case studies of different failure modes experienced by tubes located throughout the furnace. In Part II, we conclude with two additional boiler tube failure case studies.

New York regulators in April approved construction of a 20-MW energy storage system at the site of an operating coal-fired power station near Union, Broome County. When operational, the $22.3 million project, owned by AES ES Westover LLC—an AES Corp. subsidiary—will use the technology to participate in New York’s growing day-ahead market for ancillary services and regulation.

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 continue 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.

If not properly controlled, coal and coal dust can cause fires, explosions, and implosions at power plants. Strategies for promoting safer management of these combustibles include actions such as training personnel exposed to the hazards of coal and coal dust about safe handling methods.

Seven years have passed since the world’s first low mass flux vertical tube once-through furnace was put into operation by Doosan Babcock at the Yaomeng Thermal Power Plant Unit 1 in China. That boiler replaced a boiler of another design that had become unreliable. The operating experience with the Posiflow design has been so positive that the owner has since ordered and commissioned a replacement for Unit 2’s boiler. Here’s what makes this furnace design unique.

Shrinking water supplies will unquestionably constrain the development of future power plants. A hybrid system consisting of concentrated solar thermal power and desalination to produce water for a plant, integrated with a combined cycle or conventional steam plant, may be the simple solution.

One of the primary challenges of reliably burning coal is managing the corrosion experienced by the furnace heat transfer surfaces. Fireside corrosion remains a leading cause of failure in superheater and reheater tubes. Three case studies examine the different failure modes experienced by tubes located throughout the furnace.

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 begin a series of Power 101 tutorials that present these fundamentals in a clear and concise way. First up are the essentials of recovering heat from flue gas.

While the Environmental Protection Agency appears to have initially proposed to regulate power plant coal ash as hazardous waste, there are indications the Obama administration is preparing new federal rules that will at a minimum require utilities to convert coal ash impoundments from wet to dry storage to prevent leaks—a change that would cost tens of millions of dollars but also potentially increase regulated utilities’ rate base and earnings, a Wall Street firm says.

Highlighting a sharp division within the public power community, two senior House Democrats blasted the American Public Power Association for endorsing Sen. Lisa Murkowski’s effort to strip the Environmental Protection Agency of its Clean Air Act authority to regulate greenhouse gas emissions, with the lawmakers saying they have been informed that “numerous” APPA members oppose the endorsement.

In a move that could cost the state’s electricity generators an estimated $8.5 billion, New York regulators [have] issued a draft policy that would require the installment of closed-loop cooling systems at two dozen large power plants in the state, including oil, coal, nuclear and natural gas generators, to reduce fish kills and other harmful effects to wildlife in the water bodies that supply the plants’ cooling water.

Biomass has many advantages as a fuel for boilers: It’s inexpensive, readily available in many regions, CO₂ neutral, and its use warrants government subsidies. The fuel also presents unique concerns to the designers, owners, and operators of biomass plants, especially in the design of the control system.

In response to Ontario’s provincial regulatory mandates to phase out the use of coal by the end of 2014, Ontario Power Generation (OPG) is exploring its capability to employ biomass feedstocks to displace coal in some units within the OPG thermal fleet. The primary fuels employed during the respective trials at its Nanticoke and Atikokan Generating Stations have been agricultural by-products and commercial grade wood pellets. The Canadian utility has learned valuable lessons about fuel supply and logistics, and the technical challenges of safely handling and firing high levels of biomass.

Could the transformation of carbon dioxide (CO₂) into carbonates and oxides solve the problem of greenhouse gas emissions (GHG) from fossil-fired power plants? Some companies are betting that such processes could make everyone happy and even create new profits. Buzz has been growing about this approach, though the concept has been around for many years.

Tampa Electric will soon complete a comprehensive selective catalytic reduction project on all four units at its Big Bend Power Station that will make Big Bend among the cleanest coal plants in the U.S. The project — the centerpiece of the company’s 10-year, $1.2 billion air quality improvement program — is on schedule to meet all of its air quality improvement goals by mid-2010.

Short of replacement, what are your options when your original electrostatic precipitator fails to meet your current emissions and opacity requirements? The management of Big Stone Plant chose the unconventional, yet economic approach of building a pulse jet fabric filter inside the casing of the old electrostatic precipitator. The upgrades restored plant availability and prepare the plant to meet the next regulated reductions in particulate matter emissions.

Poor lignite fuel quality had plagued the Red Hills Power Plant since it began operation eight years ago. The solution: real-time measurement of coal properties that has allowed Red Hills Mine to carefully monitor fuel quality and adjust fuel collection processes to ensure that only high-quality fuel is delivered to the plant. Now all delivered fuel is consumed, and plant reliability is much improved. It’s a classic win-win project.