Coal

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.

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.

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.

The U.S. Department of Energy’s National Energy Technology Laboratory is pursuing a new integrated energy-water R&D program that addresses water management issues relative to coal-fired power generation that takes into account the major impacts of CCS on water use. The goal of this research is to promote more efficient use of water in power plant operations and increase the availability of heretofore unusable waters for power plant use. Those practices can mitigate the impacts of CCS on power plant water use and allow for continued development of energy resources.

A three-year demonstration of the TOXECON process, a technology to reduce mercury emissions while increasing the collection efficiency of particulate matter (PM), was last year successfully completed at a Michigan coal power plant, the U.S. Department of Energy’s National Energy Technology Laboratory (NETL) reported in January.

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.

The loading and discharge of conveyor belts is the area where many, if not most, of the problems in solids conveying occur. Fortunately, a new technology provides chutes to accomplish conveyor loading and discharge without blockages while minimizing the dust generated: engineered-flow transfer chutes.

Adding a selective catalytic reduction (SCR) system to an operating coal-fired plant may be an expensive and time-consuming project, but the environmental benefits are without question. However, once construction is complete and operations staff assume control of the SCR, proper measurement tools are required to monitor the catalyst performance life cycle.

Operating a boiler is not difficult, but operating a boiler safely and efficiently requires skill and proper training. Following boiler operation best practices will keep your equipment in like-new condition for years to come. This game plan includes a compendium of best practices, with web links to a number of additional key resources you should be famililar with.

In one of the most far-reaching of numerous new air regulations expected from the Obama administration, the Environmental Protection Agency (EPA) has proposed to tighten the primary federal standard for ground-level ozone, the principal constituent of smog, to within a range of 60 to 70 parts per billion, saying the tougher standard is needed to protect human health.

The Energy Department’s top fossil energy official said [in December that] he might seek exemption or relaxation of “new source review” requirements for certain U.S. coal-fired power plants that are boosting efficiency through retrofits if the plants are also good candidates for subsequent installation of carbon capture and storage systems.

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.

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.