SO₃ Issues and Answers for Fossil Fueled Power Plants is the Subject of the Hot Topic Hour on May 7^th at 10 a.m. CST

SO₃ in the flue gas stream from a fossil fueled boiler has long been a problem and a concern for power plant operators because of the corrosion in ducts and equipment caused by the sulfuric acid formed from the SO₃.  The SCR’s installed to control NO_x emissions can also create more SO₃ than exists in the raw flue gas and increase the problems.  The affect of SO₃ aerosols on particulate emissions has also been a concern - more so in some plants than others.  But SO₃ in flue gas will soon become a much bigger concern for all when new regulations on mercury and PM_2.5 are promulgated.

Activated carbon injection (ACI) has been the favorite method chosen by many utilities to reduce mercury emissions, at least in the short run, and SO₃ interferes with the ability of activated carbon to remove mercury from the flue gas.  The sulfuric acid aerosols are only 0.3 microns in diameter.  This means they can pass through a wet spray tower.  They also pass through a baghouse operating at 325°F because they are still vapors.  The acid mist fouls air heaters and baghouses, creates a visible plume, and contributes to particulate emissions.  To complicate the problem, variables such as coal type and temperatures throughout the flow path affect the SO₂ created and the conversion rate of SO₂ to SO₃ as well as the performance of control methods utilized.  To eliminate the creation of SO₃ in SCR’s, catalyst manufacturers have been working to improve the performance of catalysts to minimize the creation of SO₃ in the SCR.  Others have developed materials that can be injected into the flue gas at various points in the flow path to remove the SO₃, and still others offer WESP’s as a solution to the problem.  Is the problem now solved?  

The following speakers will discuss where we stand now relative to these problems and the performance of the various control systems:

Yougen Kong, Technical Development Manager, Solvay Chemicals Inc., will describe how dry sorbent injection of Trona, a proven technology for SO₃ removal, may also result in a significant (up to 80%) mercury reduction.

Jon Norman, PE, Technology Manager for Dry Sorbent Injection, O'Brien & Gere, will focus on recent advances in using dry sorbent injection for SO₃ removal.  Technological advances as well as new ideas to address common material handling issues will be emphasized.

Geoff Urwin, Proposal Manager with Clyde Bergemann EEC, will discuss the use of ESP's and fabric filters in conjunction with the injection of a dry sorbent, such as Trona or hydrated lime, into the flue gas stream at a carefully selected injection location.  The presentation will include a brief description of the sorbent used, injection location, process modeling and equipment considerations for a successful installation.

Edward V. Bowes, Manager, Fossil & Hydro Engineering, Dominion Resources, will discuss the Marsulex "Clean Stack Technology" installed and running at the Glen Allen Plant.

James "Buzz" Reynolds, Vice-Pres./Wet ESP, Siemens Energy, Inc., Environmental Systems & Services, will provide an update on WESP technology and it’s capability to capture SO₃.

John C. Caine, General Manager, Southern Environmental, Inc/ SEI, will discuss WESP compared to solvent injection for SO₃ removal.

To register for the “Hot Topic Hour” on Thursday, May 7^th at 10:00 a.m. CST, click on: http://www.mcilvainecompany.com/brochures/FGDnetoppbroch/Default1.htm .

Bob McIlvaine

847 784-0012 ext. 112

rmcilvaine@mcilvainecompany.com