tech details

Mercury Sorbent Delivery System for Flue Gas

Opportunity

The Department of Energy’s National Energy Technology Laboratory (NETL) is seeking licensing partners interested in implementing United States Patent Number 7,494,632 titled "Mercury Sorbent Delivery System for Flue Gas."

Disclosed in this patent is NETL’s system for the removal of elemental mercury (Hg) (and other contaminants) from flue gas streams, which involves utilizing a layer of sorbent particles contained within the filter fabric of a filter bag in a flue gas scrubbing system. Gases generated from combustion sources such as coal gasifiers, coal-fired electrical generating plants, and ore smelters are candidates, especially if the gases already need particulate removal, and if cross-contamination of fly ash by-product by sorbent/mercury is to be avoided. More than 90 percent of elemental mercury was shown to be removed when activated carbon particles were tested in this process. The particle-loaded membranes may also act as oxidizers of the elemental Hg ahead of wet scrubbers. In addition, cleanup of aqueous waste streams is possible.


Overview

Mercury is a natural contaminant in fossil fuels. In high temperature gas streams in power plants, nearly all of the mercury in coal ends up in the flue gases (about 1 part per billion (ppb) concentration) after combustion. These flue gases may contain mercury in elemental, oxidized, and particulate forms. Elemental mercury in exhaust gases does not adhere to soot and other particles entrained with the gases, but instead tends to remain in the vapor phase, making it the hardest form of mercury to remove.

One typical adsorbent for use with this invention is an activated carbon particle having a particle size of 2 microns to about 30 microns. This small size effectively reduces mass transfer resistance by decreasing the capture distance. Further, the low consumption rate compared to duct injection makes employment of promoted carbons as well as other high capacity sorbents economically feasible. As the mercury-containing flue gas passes through the filter bag layers, the first layer removes particulates in a separate stream. The reduced-particle flue gas then enters the mercury adsorbent media, where the adsorbent removes elemental mercury vapor from the dust-free flue gas.


Significance

This technology provides:

  • A method of removing elemental mercury from high temperature flue gas streams and contaminated aqueous streams
  • A way of reducing the amount of toxic mercury that enters the environment
  • An inexpensive method of flue gas clean-up based on reduced consumption of sorbents


Related Patents

U.S Patent No. 7,494,632, issued February 24, 2009, titled "Mercury Sorbent Delivery System for Flue Gas.”

Inventor: Edgar Klunder


For more information Contact Us