This week’s Two Day Hot Topic Hour was Material Handling for Coal-fired Power Plants

Presenters on Thursday April 15^th were

Jack Hilbert, Principal Consultant at Pneumatic Conveying Consultants Inc., discussed the issues related to current practices for the injection of dry sorbents (DSI) for the mitigation of mercury, SO₂ and SO₃ in flue gas from fossil and biomass-fired steam generators. These challenges require attention beyond the normal pneumatic conveying issues of capacity, distance, pipe size and the resultant energy requirements to meet the system parameters. Issues, which are relative to specific sorbents such as temperature, moisture, and particle size and other issues common to most all of the DSI systems such as equal distribution to multiple injection points, large variation in rate turndowns, etc., also present challenges to the system designer. His advice was

• Use dilute phase, pressure systems for injection applications.
• Use two-phase or dense phase for transfer applications.
• Do not use injection lances < 1-1/4” diameter.
• Keep in-line conical splitters in the vertical plane.
• Tapered manifold splitters are installed in the horizontal plane.
• Line chargers are chosen based on system specific considerations.
• Be aware if the sorbent has sensitivity to moisture and/or temperature.

Charles Alack, President of Semi-Bulk Systems, Inc., discussed limestone supply options and limestone slurry process technology for FGD projects focusing on the VACUCAM^(R) Ejector Mixer modular processes for limestone handling and dispersion. The process handles large volumes of pulverized limestone powders and very efficiently produces 30+ percent limestone slurry to meet any scrubber demands.  The process requires minimal real estate, operator attention and maintenance. Systems were recently installed at Minnesota Power, Southern Power Crist and at Ameren's Sioux.

An important subject was covered in the discussion. Dry grinding eliminates the ball mills. In previous McIlvaine webinars speakers have attributed significant toxic metal contamination of the FGD wastewater to the high nickel grinding balls. Since the dry grinding would assumedly occur with less toxic metal contamination, this could be a significant advantage.

Jerry VanDerWerff, National Sales Manager for Sorb-N-Ject technology at Nol-Tec Systems, covered the selection and application of pneumatic conveying methods and design considerations for pneumatic conveying of dry sorbents to mitigate pollutants in the power industry.  Dense phase and dilute phase pneumatic conveying allow flexibility in handling these dry sorbents.  Pneumatics can also be used to fluidize dry sorbents to promote flow from silos and hoppers. Trona presents some challenges over and above that encountered with sodium bicarbonate but there is not enough difference to affect the sorbent selection.

James Fisher of Clyde Bergemann Delta Ducon discussed options for flyash pond elimination. Switching to dry bottom ash conveying improves boiler efficiency as well as eliminating the ash pond. One approach is to dewater bottom ash in a tank with a scraper chain and then purify the overflow water.

Presenters on Friday April 16^th were

Gerald Huiras, President and CEO of FLSmidth Pfister, Inc., detailed their experience in handling and metering coal, biofuels, and lime in power plants for the past twenty years. Pfister is a German based subsidiary of the Danish parent. It has more than 2000 installations of feeders handling coal and other fuels in power plants. Rotor weigh feeds have advantages over belt feeders. At the 4 x 300 MW Rio Escondido power plant belt feeders were successfully replaced. Maintenance was reduced and the frequent shutdowns eliminated.

Daniel E. (Dan) Charhut, Vice-President Sales & Technology, and Kevin McDonough, Director of Sales Americas at United Conveyor Corporation, introduced multiple technical options to convert wet ash handling systems to dry ash handling systems, eliminating the need for ash ponds.  Bottom ash and flyash systems were discussed, along with criteria for selection of the appropriate conversion technology relative to unique power plant conditions. The conveyor system allows use of existing piping, is easy to retrofit, reduces wastewater treatment, and has low installed costs.

Dr. Desmond Smith, Ph.D., Vice-President of BRUKS Rockwood Inc. West Coast Office, provided the rationale behind biomass handling system designs and material selection. The  source, timing, quality, size, moisture, contaminants, storage characteristics, energy content and suitability to end use of the biomass material impacts the material handling selection. There is a big variation of fuels from whole logs to bio-char.

The Bios, Abstracts and Photos can be viewed as follows: BIOS, PHOTOS, ABSTRACTS - APRIL 15-16, 2010.htm

The individual slides can be viewed in the FGD DECISION TREE as follows:

Jack Hilbert – Pneumatic Conveying Consultants

FGD Continuing Decision Process For: Products

A Primer in Dry Sorbent Injection Conveying Systems and Components, presented by Jack Hilbert, Pneumatic Conveying Consultants. Hot Topic Hour April 15, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Jack Hilbert - Pneumatic Conveying Consultants -4-15-10.pdf

Jerry VanDerWerff – Nol-Tec Systems

FGD Continuing Decision Process For: Products

Application of pneumatic conveying methods and design considerations of pneumatic conveying of dry sorbents to mitigate pollutants in the power industry.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Jerry VanDerWerff - Nol-Tec Systems - 04-15-10.pdf

James Fisher – Clyde Bergemann Delta Ducon

FGD Continuing Decision Process For: Products

Material Handling for Coal-fired Power Plants, presented by James Fisher, Clyde Bergemann Delta Ducon. Hot Topic Hour April 15, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/James Fisher - Clyde Bergemann Delta Ducon - 04-15-10.pdf

Charles Alack – Semi-Bulk Systems, Inc.

FGD Continuing Decision Process For: Products

Limestone Slurry Production from Pulverized Limestone vs. Crushed Limestone & Wet Ball Mills. Hot Topic Hour April 15, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Charles Alack - Semi-Bulk Systems - 4-15-10.pdf

Gerald Huiras – FLSmidth Fister

FGD Continuing Decision Process For: Products

Dosing and Metering to Perfection, presented by Gerald Huiras, FLSmidth Fister. Hot Topic Hour April 16, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Gerald Huiras - FLSmidth Fister - 04-16-10.pdf

Daniel Charut and Kevin McDonough – United Conveyor Corp.

FGD Continuing Decision Process For: Products

Wet-to-Dry Conversion Solutions for Ash Handling Systems, presented by Daniel Charut and Kevin McDonough, United Conveyor Corp. Hot Topic Hour April 16, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Kevin McDonough, Daniel Charut - United Conveyor - 04-16-10.pdf

Dr. Desmond Smith - BRUKS-Rockwell, Inc.

FGD Continuing Decision Process For: Products

The Rationale Behind Biomass Handling System Designs - North American Case Studies, presented by Desmond Smith, BRUKS Rockwood, Inc. Hot Topic Hour April 16, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Desmond Smith - Bruks Rockwell - 04-16-10.pdf