Plant Design

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.

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.

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.

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.

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.

Utilities struggling to meet renewable portfolio standards requirements have studied the conversion of existing coal-fired boilers to burn biomass. The results of those studies have been mixed, although test burns continue; the results of one such test are included. Overall, the market is tending toward smaller biomass projects, and the low price of natural gas is perhaps the biggest reason utility-scale projects are now few and far between.

The international policy framework regulating the emissions of greenhouse gases from industrial and utility boilers is in flux. Meanwhile, most boiler owners are evaluating potential strategies for when, not if, more stringent emissions reduction regulations are put in place. One of the most attractive compliance options is the cofiring of biomass in existing coal-fired boilers.

Duke Energy and Progress Energy announced January 10 that they are combining to create the nation’s biggest electric utility. The $13.7 billion deal is likely to draw tough scrutiny from federal and state regulators—and some protests from big power buyers—given the companies’ overwhelming market dominance in North Carolina and more modest operational overlap in South Carolina.

Ringing what may be the death knell for the $3.5 billion Taylorville IGCC project, the Illinois Senate voted 33-18 in early January against authorizing construction of a coal gasification and power generating plant proposed in the state by Tenaska.

Energy efficient and environmentally responsible dry bottom ash technologies will soon be required by regulation. Progressive companies will bring their plants into compliance early because it’s a good business strategy. Here are your compliance options.

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.

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.

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.

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.

When the Łagisza power plant began commercial operation in late June 2009, it marked the beginning of a new era in the evolution of circulating fluidized bed (CFB) technology. At the heart of this 460-MW plant is the world’s largest CFB boiler, which is also the world’s first once-through unit supercritical CFB boiler.

Reducing dust from coal conveyors has moved from a housekeeping chore to a safety challenge, especially with Powder River Basin coals. Here’s what you need to know about the latest coal-handling system design.

FirstEnergy has announced plans to repower two coal-fired units at the R.E. Burger plant to burn biomass. Conversion of the two units, expected to be completed by 2012, gets the utility off the hot seat with the EPA for alleged Clean Air Act violations.

Recent improvements in the performance of steam power plants have been achieved with advanced computerized controls. These new control schemes not only reduce fuel consumption and make the plant much more responsive, but they also can significantly decrease start-up commissioning time and cost.

The UK has all but doomed new coal-fired capacity by simultaneously setting binding carbon reduction goals and by requiring carbon capture and sequestration (CCS) of carbon emissions from new  mid-size coal-fired power plants. Existing plants will also be required to retrofit their plants when CCS technology is demonstrated, now estimated to happen by 2020.

Many coal-fired power stations built before 1980 were designed for handling relatively easy-handling lump coal. If your plant’s bins, bunkers, and silos aren’t up to dealing with today’s range of more variable coal properties, this case study shows one way to minimize coal flow problems.

The 200-MW Dallman Unit 4 under construction in Springfield, Ill., is expected to cost approximately 20% less to operate per megawatt-hour than the most efficient of the three existing Dallman units. A composite stack liner is one element enabling that cost savings.

The flue gas desulfurization process requires the use of aggressive liquids that significantly shorten the life of typical construction materials such as metals and concrete. That makes fiberglass-reinforced plastic (FRP) the material of choice for many components in a typical flue gas desulfurization (FGD) system.

Replacing existing, older-generation controlled-flow split-flame burners on Unit 1 at the Seminole Generating Station with Foster Wheeler’s new low-NO_x burners and overfire air additions reduced NO_x emissions. This case study provides all the details and post-installation test results.

Many automation engineers are coming face to face with real fieldbus applications for the first time. Fieldbus (the use of digital communications networks for distributed instrumentation and control) is a wonderful technology with many benefits, but fieldbus installation requires some additional considerations over and above normal 4-20 mA projects. In this article, I present some of those issues and show you how to deal with them.

Reducing NO_x, SO₂, and other air pollutants continues to be a challenge for the power generation industry. The technologies are well-understood, but the devil is always in the details, especially when a complex treatment system is retrofitted to an existing plant.

The most common method for reducing SO₂ from plant emissions is the conventional lime- and limestone-based flue gas desulfurization (FGD) system. Material-handling systems for limestone and gypsum present specific challenges and opportunities that differ from those of coal-handling systems. This article looks at factors to consider  before and during the design of a new material-handling system. The choices you make about these many variables will determine the cost and longevity of your system.

In early June, New York Gov. David Paterson proclaimed that his state would commit $6 million to buttress a carbon capture and sequestration (CCS) viability study for the development of a new 50-MW clean coal plant in Jamestown, in western New York. The circulating fluidized-bed (CFB) project, which would use pure oxygen to combust coal and subsequently capture and sequester 90% of emitted carbon dioxide (CO₂), would be “the first of its kind in the world” and could potentially enable New York firms to launch exports of the technology worldwide, Paterson promised.

In recent years, Sargent & Lundy has evaluated many potential sites for new coal-fueled generation. Some of the sites studied were lands adjacent to existing power plants (brownfield sites); others were undeveloped greenfield sites. The numerous technical, environmental, economic, and regulatory issues that bear on power plant siting generally apply to both brownfield and greenfield […]

Production from Wyoming Powder River Basin (PRB) coal mines ended last year with a increase of only about 1.1%, reflecting a record 451.3 million tons, according to the Department of Energy’s Energy Information Administration. Production of PRB coal spiked with a record 10% growth in 2006 following two derailments on the PRB’s main triple-track line […]

The FutureGen Industrial Alliance Inc. selected Mattoon, Ill., as the site of the $1.8 billion FutureGen project just before Christmas, but the plant may never move off the drawing board.. FutureGen, the proposed prototype of a near-zero-emissions coal plant, is to demonstrate advanced technologies for coal gasification, electricity production, emissions control, CO 2 capture and […]