Over the past 17 years — dating back to the 1990 Clean Air Act Amendments and including the introduction of retail competition — coal-fired power plants have become much cleaner and more efficient. Utilities have spent many billions of dollars to install pollution controls for regulatory reasons, and only slightly less to upgrade turbine-generators and […]
The February 1907 issue of POWER magazine reported on the construction of a new coal-fired steam engine plant on the Merrimac River outside of Lawrence, Mass. According to the plant’s owner, "the simplest and most flexible means for handling coal… to the furnace is by animal muscle… that brings the coal to the firing floor […]
To borrow shamelessly from Charles Dickens, one of my favorite authors, for coal in 2006, "It was the best of times, it was the worst of times." No Escape The year began in horror. On January 2, most likely a result of a severe lightning strike, methane gas in the International Coal Group’s Sago Mine […]
Large-particle ash (LPA), also called popcorn ash (Figure 1), is a serious concern for many coal-fired utility boiler operators who have retrofitted their unit(s) with a high-dust selective catalytic reduction (SCR) system. LPA formed in the boiler can easily carry over into the SCR reactor (Figure 2), where it often causes catalyst erosion damage and […]
Layering NOx control technologies can reduce a coal-fired unit’s NOx emissions to levels achievable by selective catalytic reduction alone. Advanced Combustion Technology Inc. (ACT) (www.advancedcombustion.net) has demonstrated that using several in combination can cut emissions from boilers firing eastern bituminous coal or No. 6 oil to less than 0.15 lb/mmBtu. The following two case studies […]
Safeguarding coal-handling assets;
Giant wind turbine hard to bear
Concerns about global climate change have prompted interest in reducing or eliminating the carbon dioxide (CO2) emissions of fossil fuel-fired power plants. Here’s a guide to the technology and economics of three CO2 capture methods: postcombustion separation of CO2 from flue gas (applicable to existing plants), and oxygen-fired combustion and precombustion capture (suitable for new coal-fired capacity, including IGCC plants).
For some gencos, the dearth of operating experience for integrated gasification combined-cycle plants adds too much uncertainty to the risk/reward equation for new-capacity technology options. For others, the possibility of being able to comply with air pollution limits as far out as 2018, as well as to meet all-but-certain CO2 caps, makes IGCC well worth investing in—now.
Slagging and fouling of furnaces and boilers’ convective pass top the list of costly coal plant O&M problems. Although sootblowing is a tried and true solution, running sootblowers too often can erode boiler tubes. Lehigh University’s Energy Research Center has developed an "expert" sootblowing system that has outperformed experienced operators’ "seat of their pants" sootblowing procedures on two head-to-head field tests.
Fuel flexibility isn’t free. Whether you’re equipping a new power plant to burn more than one type of coal or retrofitting an existing plant to handle coal blends, you’ll have to spend time and money to ensure that all three functions performed by its coal-handling system—unloading, stockout, and reclaim—are up to the task. The first half of this article lays out the available options for configuring each subsystem to support blending. The second half describes, in words and pictures, how 12 power plants—both new and old—address the issue.