“MATS Timing and Technology Options” discussed in Hot Topic on August 7, 2014

The webinar was crafted to assist power plants dealing with meeting the new Mercury and Air Toxic Standards (MATS rules). The challenge is that the best solution for mercury removal may not be  the best solution for removing the necessary quantities of acid gases and fine particulate. The best air pollution solution may not be the best environmental solution when water and solid waste aspects are considered. So you need to travel back and forth between technology solutions to find the one most appropriate to your needs. The McIlvaine system for doing this is equivalent to a trip using GPS and is labeled Global Decisions Positioning System (GDPS).

This GDPS takes you back and forth through a number of free websites each focused on one of these decision areas Continuous Analyses. The webinar referenced these websites and displays.

The webinar included insights from experts on the latest developments and how they may affect decision making.   Those experts included:

§   Gifford  Broderick, Combustion Components Associates, Inc

§   Kevin Crosby, Technical Director, The Avogadro Group, LLC 

§   Paul Barilla, P.E., Consultant 

The large number of uncertainties makes it difficult to determine a course of action to deal with the Mercury and Air Toxics Standard.  You may initially reject plant retirement as a solution but as the cost of the compliance options mount, you may have to revisit that decision. You may make a tentative decision to use wet scrubbing but then find that the water pollution control costs make this unattractive.  A dry scrubber may look attractive until you evaluate the restrictions on flyash sales and landfill costs.  The result is that the MATS decision process is complex and can be likened to a maze. This webinar provided the equivalent of a GPS system to negotiate the maze. It could be called the MATS Global Decisions Positioning System^™ (GDPS).

MATS GDPS

Plant retirement is the first consideration.  Capital investment to meet MATS will be substantial.  An old plant may only be valued at $500/kW. Expenditures to meet MATS may in an extreme case be $400/kW.  So you are nearly doubling your investment. Will it be worthwhile? Here are some of the factors to be considered. 

  1^st Decision Tree Stop:  Plant Retirement Decision Tree

Another option is to convert to natural gas-firing in your existing boiler. Gifford Broderick, Combustion Components Associates, addressed this option. Converting to natural gas-firing could cost less than $ 100/kW. This compares favorably to the cost of scrubbers and other air pollution control to upgrade the coal-fired power plant. It is also 1/10 the cost of a new GTCC plant.

This is the initial stop but will need to be revisted as the cost of the MATS compliance option is further developed.  The decision to upgrade to meet MATS has to start with particulate control. The MATS rule allows the operator to either meet a very low PM_2.5 limit or to separately measure toxic metals. Due to the difficulty in measuring toxic metals virtually all plants will opt for the lower particulate limit.

        Decision Tree Stop:  Start immediately with a monitoring program

You need to determine what measurements need to be made in advance of an investment decision and then what measurements will be needed to avoid violations when the solution is up and operating.  Kevin Crosby, Technical Director, The Avogadro Group, LLC, addressed the monitoring needs  at all points along the way. There are continuous monitoring and periodic testing options for toxic metals, mercury and HCl. So these approaches should be determined in advance.

Due to some oversights in the mercury monitoring rules, the selection of  a monitoring method may affect the equipment choices. If you use sorbent traps rather than mercury CEMS you may need better particulate control. The reasoning is that the sorbent traps pick up particulate mercury. Kevin addressed this observation by saying that a filter prior to the sorbent trap would eliminate the measurement of particulate mercury in the sorbent trap itself. However, if particulate mercury is substantial it would need to be addressed.

       2^nd Decision Tree Stop:  Particulate Decision

There are proposed regulations in the U.S. dealing with coal combustion residues and effluent water quality.  Dry scrubbers create combustion residues and wet scrubbers create effluent.  So MATS decisions have to take these future standards into consideration.

3^rd Decision Tree Stop:  Solids Regulations and Flyash Salability

4^th Decision Tree Stop:  NO_x Control Technology

There is a requirement in MATS to reduce HCl. EPA says much of the benefit of MATS is the SO₂ reduction which will coincidently take place with HCl capture.

5^th Decision Tree Stop:  Select FGD Type and Reagent

MATS HCl Capture Table Low Sulfur Coal and Use Existing Precipitator

One McIlvaine website covers the wet option Wet Calcium FGD - Continuous Analyses

Another McIlvaine website covers DSI, spray driers, and circulating dry scrubbers  Dry Scrubbing - Continuous Analyses

Hot gas filtration for all MATS requirements—See McIlvaine Website Hot Gas Filters - Continuous Analyses

6^th Decision Tree Stop - Air Toxics

Three air toxics addressed in MATS are mercury, HCl and toxic metals. The HCl reduction is tied into the FGD.  The toxic metals will be removed by the particulate collector. So that leaves mercury as the remaining contaminant to address.  McIlvaine has covered all the options for mercury reduction at Mercury Removal - Continuous Analyses.

Individual presentations follow:

MATS Timing and Technology Options Webinar - Hot Topic Hour August 7, 2014

The webinar was crafted to assist power plants dealing with meeting the new Mercury and Air Toxic Standards (MATS rules).

Revision Date: 8/7/2014

MATS Emission Testing and Monitoring Requirements, by Kevin Crosby, Montrose Environmental (The Avogadro Group) - Hot Topic Hour August 7, 2014

Kevin addressed monitoring needs. There are continuous monitoring and periodic testing options for toxic metals, mercury and HCl.

Revision Date: 8/7/2014

Converting to Natural Gas for MATs Compliance by R. Gifford Broderick, Combustion Components Associates - Hot Topic Hour August 7, 2014

Giff Broderick addressed the option of converting to natural gas-firing in an existing boiler.

Revision Date: 8/7/2014