NEWS RELEASE                                                                                                                  MAY 2013

Market to Remove Mercury From Air is Complex

The market for equipment and consumables to remove mercury from exhaust gases is growing and will surpass $1 billion/yr over the next five years. However some new factors, both positive and negative, are making the market more difficult to predict. This is the conclusion reached by McIlvaine in its continually updated Mercury Air Reduction Markets. The new factors are:

  • Value in removing other heavy metals: There has been considerable research devoted to the mercury removal performance of activated carbon. Relatively little is known about the performance to remove other heavy metals. However, evidence to date points to the simultaneous ability to remove selenium. This potential has not been seen as particularly valuable since there are no tough regulations on selenium emissions to the air. There are regulations limiting selenium discharge in scrubber wastewater. This is resulting in multimillion dollar projects to treat the scrubber wastewater for selenium removal. The conventional wisdom has been that where there are wet scrubbers activated carbon will not be used. But now that the selenium removal potential has been discovered, there may be occasions where both activated carbon and scrubbers would be used.
  • Permanent removal from the environment: Capturing the mercury is only the first step in assuring that one is not just transferring the mercury from the air to either the soil or to water. Suppliers are developing cement compatible sorbents which will allow use of the flyash with the mercury to be sold for cement production. Once encased in concrete, it can be considered removed from the active environment. Another development has to do with chemicals used to prevent re-emission from the recirculating scrubber liquor. Without these chemicals, mercury chloride in solution converts to elemental mercury and is re-emitted as a vapor. The scrubber chemicals not only prevent this but also form large compounds. This means that mercury and other heavy metals can be separated from the wastewater and from fine sludges. A variation on this uses activated carbon in the scrubber slurry.
  • Unique processes: Variations from plant-to-plant and application-to-application are challenging designers. For example, cement plants are not steady emitters. The emissions are in surges. The mercury accumulates in the recirculating kiln dust and then is released based on raw mill operation. Some novel approaches have been developed to deal with this problem.
  • Activity outside the U.S.: Mercury removal has been required from incinerators in many European and Asian countries, but the U.S. has been the first to promulgate stringent limits for utility boilers, industrial boilers and cement plants. Recently, there has been acceleration in efforts to regulate the emissions from these plants in other countries.
  • New options for capture: New products are becoming commercial. They will not only reshape the competitive landscape but encourage lawmakers to enact even tougher regulations. The combination of chemicals introduced with the coal and scrubbers to capture the soluble mercury compounds is proving more effective than previously thought. One reason is the use of additional chemicals to prevent re-emission. New versions of activated carbon provide higher efficiency. Other sorbents are being developed to compete with carbon.

    Because of these complexities it is desirable to reassess the market continually. This is accomplished in the online continuously updated, Mercury Air Reduction Markets.

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