If coal leaving a pulverizer isn’t dry, it may plug up the coal pipes leading to the boiler. The coal-drying process in a pulverizer is similar to that used by flash dryers. Certain coals should be preheated to make them more combustible. Generally, preheating is done on higher rank coals — those with a low […]

Historically, cyclone-fired boilers have been characterized as big emitters of NOx due to the very high temperatures in their primary combustion zone. Uncontrolled levels from 0.8 to 1.9 lb/mmBtu have been typical. The design of cyclone-fired units makes them impossible to retrofit with standard low-NOx burners. Prior to 1997, the conventional wisdom was that cyclone […]

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 […]

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 […]

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 […]

Harvard Business School Professor Clayton Christensen coined the term "disruptive technology" in his best-selling 1997 book, The Innovator’s Dilemma. According to Christensen, a disruptive technology unseats a dominant technology by creating products that are so much cheaper or better in one or more ways that they quickly become the new mainstream standard, transforming an entire […]

Renewables require rethinking just about everything/Torque-splitting drive train improves wind turbine reliability/Waste gas–burning engines reach milestone/Hybrid power plant targets pipeline losses/Power from paint/Gulf Coast Power Association conference report/Pat Wood talks about the challenges facing ERCOT

The U.S. electric utility industry has long encouraged its customers to get more value from their electricity dollar. Today, the industry—facing volatile costs and mounting concerns about the environment—is coming together to create a new role for energy efficiency—one that enables technology to deliver more value to customers and electric utilities alike. For example, "smart" […]

Fireproofing switchyards From an insurance carrier’s perspective, we fully condone the use of on-line condition monitoring for large, critical transformers ("Monitoring key gases in insulating oil keeps transformers healthy," POWER, October 2006). However, another issue that the transformer failure and subsequent fire at Arizona Public Service’s West Wing Substation in 2004 highlights is the need […]

Safeguarding coal-handling assets;
Giant wind turbine hard to bear