Coal

Several states have already instituted mercury emission limits in expectation of tightening mercury emission rules that will require reductions of up to 91%. Coal-fired plants searching for an economical way to meet the new limits may need to look no further than replacing their baghouse filter elements.

A recent NOx reduction project added selective catalytic reduction equipment to each of the two 640-MW, mixed coal–fired units at the St. Johns River Power Park. The selection of precisely the right catalyst required extensive long-term testing with “mini” reactors. Once the right catalyst formula was identified, the actual retrofit project was completed in a mere 23 months, an aggressive project schedule that required overcoming many design and construction challenges.

Dallas-based Luminant, Texas’ largest power generator, on September 9 filed a legal challenge against the Environmental Protection Agency’s (EPA’s) Cross State Air Pollution Rule (CSAPR) but said the newly finalized rule that will require generators to dramatically reduce sulfur dioxide and nitrogen oxide emissions from power plants had forced it to idle two coal-fired units and reduce capacity at three other units. This decision follows a similar decision made by American Electric Power to shutter 6GW of coal-fired plants in June.

The U.S. Environmental Protection Agency (EPA) has proposed new Clean Water Act section 316(b) regulations for once-through cooling water intake structures. Comments on the proposed rules closed in August, and a final rule is expected mid-2012. The EPA estimates that at least half of the power plants using once-through cooling will be required to implement a best technology available solution in coming years. That typically means barriers and screens, but you may want to consider other options.

Just two weeks after the Environmental Protection Agency (EPA) withdrew its smog rule, the agency confirmed it would not meet a Sept. 30, 2011, deadline for issuing proposed New Source Performance Standards (NSPS) to limit greenhouse gas emissions from new, modified, and existing power plants. The agency did not specify a new deadline for proposing the rule.

Power plants often produce wastewaters that contain salts, such as those from wet gas scrubbing, coal pile run-off, and leachate from gypsum stacks. Evaporation of those liquid wastes in a modern zero liquid discharge system produces clean water that is recycled into the plant plus a solid product suitable for landfill disposal. Here are the options to consider.

President Obama has scuttled the Environmental Protection Agency’s (EPA’s) smog rule, saying that he had underscored the importance of reducing regulatory burdens and uncertainty. The decision has dealt a blow to environmental groups—which are contemplating legal action—and won the Democratic president praise from Republicans and industry groups.

Quin Shea, vice president, environment for the Edison Electric Institute, comments on the Utility MACT rule that is expected to be finalized in November.

Pulverizers prepare the raw fuel by grinding it to a desired fineness and mixing it with the just the right amount of air before sending the mixture to boiler burners for combustion. In Part I of this three-part report, we examined the essentials of pulverizer design and performance.  In the second part, we discuss the importance of fuel fineness. In the final article, we will discuss the importance of air and fuel measurement.

Complying with various state (and expected federal) requirements governing mercury removal from the stack gas of coal-fired power plants has usually been achieved by adding an expensive activated carbon injection system. Now there is another alternative: a catalyst that features higher mercury oxidization activity than conventional catalysts while maintaining the same SO2 to SO3 conversion activity—and all at a lower operating cost. Full-scale installations are under way at several Southern Company plants that burn a variety of coals.

Utilizing engineering ingenuity and today’s developing computational fluid dynamics tools, a new classifier design is now available that significantly improves fineness from pulverizers without the heavy costs associated with dynamic classification or any downsides on pulverizer capacities, maintenance, and parasitic power.  Instead, operational flexibility and improved emission control options are enhanced.

Australia Pursues Carbon Tax. Australia’s Prime Minister Julia Gillard on July 10 laid out an ambitious plan to cut national greenhouse gas emissions by 5% of 2000 levels by 2020 by imposing a A$23 (US$23.4) per metric ton carbon tax, starting next year. If parliament approves the plan before year-end, the carbon tax will increase […]

Now that many flue gas desulfurization (FGD) systems are reaching middle age, corrosion repairs of structural and process vessels are becoming more common. Corrosion is caused by condensates of acids formed during the FGD process, which accelerate pitting and crevice corrosion, particularly in scrubbers where high sulfate solutions are present. Scrubbers lined with 2205 duplex stainless steel are among the most vulnerable to pit or crevice corrosion, from both chlorides and fluorides.

From the East Coast to the Lone Star State, a number of elected officials and power industry representatives are bashing the new aggressive regulation aimed at controlling specific power plant emissions. Complying with a federal court mandate, the U.S. Environmental Protection Agency (EPA) finalized the Cross-State Air Pollution Rule (CSAPR) on July 6. The new […]

As barriers to new coal-fired generation expand and enthusiasm for nuclear plants wanes, the commissioning of natural gas–fired plants promises to increase. However, gas plants pose hazards, too. An explosion last year that was caused by unsafe use of natural gas to blow residue from a gas pipeline during commissioning of a gas-fired power plant has focused regulator and industry attention on finding safer alternatives for this task. Fluor shares its gas pipeline cleaning best practices.

A web supplement to the September issue with details of global power shortages.

Heat waves, droughts, and other weather and climate phenomena; economic woes; aging or inadequate infrastructure; fuel shortages. These are some of the most obvious causes that have led to record peaks in power demand or sudden drops in available capacity. The results have been sometimes debilitating load-shedding, brownouts, and blackouts around the globe this summer (and, in some cases, for much longer). Here’s an overview of which countries are affected by which difficulties. For a more detailed look at the extent of shortages and what’s causing them, visit Web Exclusives at https://www.powermag.com

A brush fire that spread and detonated explosives stored at the Evangelos Florakis naval base in Mari on the southern coast of Cyprus on July 11 killed 13 people, injured 62 others, and severely damaged the Vassilikos Power Station—an oil- and gas-fired plant that supplied almost 60% of the island nation’s power. Cyprus, which was once considered an “economic miracle,” has been battling crippling power shortages that have beleaguered its financial and tourism sectors since the blast and left it on the verge of economic collapse.

The regenerative air heater on a typical steam generator usually accounts for over 10% of a coal-fired plant’s thermal efficiency. A poorly performing air heater will cause an increase in the gas outlet temperature, often reducing the electrostatic precipitator collection efficiency and baghouse reliability. Recent design innovations enable restoration of this lost performance.

Pulverizers prepare raw fuel by grinding it to a desired fineness and mixing it with the just the right amount of air before sending the mixture to boiler burners for combustion. In Part I of three parts, we’ll examine the essentials of pulverizer capacity, what should be done after a coal pulverizer fire or other incident, and how to tune up pulverizer performance. In future articles we’ll discuss measuring pulverizer performance and performance optimization.

American Electric Power recently announced plans to retire over 6,000 MW of coal-fired generation in response to two looming Environmental Protection Agency air quality regulations. Is AEP exaggerating the impact of these regulations? Some members of Congress believe that to be the case. AEP disagrees.

Continuing the House Republicans’ aggressive attack on Obama administration environmental proposals, a House subcommittee approved legislation in June to prevent the Environmental Protection Agency from regulating coal ash as a hazardous waste—one of two options the EPA is considering for tightening coal ash management regulations in response to a disastrous leak from a Tennessee Valley Authority ash impoundment in 2008.

Dominion Virginia Power has asked the Virginia Corporation Commission for approval to convert three aging and relatively small coal-fired plants to biomass, saying the move would provide substantial long-term savings to customers while cutting air emissions and creating hundreds of forest-related and trucking jobs in the state.

Why should utilities consider converting existing coal-fired plants to burn gas? We explore the rationale for fuel switching, some of the options available for the conversion of coal-fired units, technical considerations related to conversion, and some of the financial considerations that will impact the final decision.

Companies continue to increase the size of carbon capture and sequestration test projects. Mitsubishi Heavy Industries (MHI) has launched operation of what it calls the world’s largest demonstration of carbon capture on a pulverized coal plant.

Kansas City Power & Light (KCP&L) began engaging stakeholders in 2003 to develop consensus on a regional energy plan designed to balance customers’ desire for low electricity costs with system reliability needs and environmental requirements. The culmination of that plan was the completion of Iatan 2, which entered service in August 2010. For executing an innovative energy plan that reduced overall fleet emissions, ensuring the region’s future electricity supply, and completing an approximately $2 billion project in time for the summer 2010 peak load by using innovative contracting and project controls, KCP&L’s Iatan 2 is awarded POWER’s 2011 Plant of the Year Award.

Cycling your steam power plant is inevitable, so now is the time to learn how to minimize equipment damage and assess the true costs of cycling. Whether cycling is required by the grid operator because of renewable integration or other factors, you must be proactive about updating operating processes and upgrade equipment so the transition to cycling operation goes smoothly.

As coal-fired power plants increasingly operate in cycling modes, many plants are confronting the potential for higher levels of component damage and degraded performance of environmental control equipment. Generators and EPRI are working together to find ways to mitigate the effects of cycling operation and to manage the transition of formerly baseload plants to flexible operation.

It may seem counterintuitive, but the strategic coupling of simple- and combined- cycle technologies with renewable generation could establish the conditions necessary for adding more renewable megawatts to transmission grids around the world.

Underground coal gasification (UCG) is the gasification of coal in-situ, which involves drilling boreholes into the coal and injecting water/air or water/oxygen mixtures. It combines an extraction process and a conversion process into one step, producing a high-quality, affordable synthetic gas, which can be used for power generation. Still in the early stage of commercialization, UCG is poised to become a future major contributor to the energy mix in countries around the world.