A look at clean coal technology in the 21st century

Clean coal technologies impact our daily lives, Gates writes. One of those clean coal technologies is dry sorbent injection, which removes hydrogen chloride and other acid gases through two basic steps.

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    Processed coal streams out into a pile after being cleaned in the prep plant at the Century Mine near Beallsville, Ohio. Numerous clean coal technologies impact our daily lives, Gates writes.
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Dry Sorbent Injection (DRI) achieves between 40 to 75% removal of Sulfur Dioxide and acid gases and is one of the numerous clean coal technologies that impact our daily lives.  According to the U.S. Energy Information Administration, DSI systems remove hydrogen chloride (HCl) and other acid gases through two basic steps:

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  • Step one. A powdered sorbent is injected into the flue gas—combustion exhaust gas exiting a power plant—where it reacts with the HCl. The sorbents most commonly associated with DSI are trona (sodium sesquicarbonate, a naturally occurring mineral mined in Wyoming), sodium bicarbonate, and hydrated lime.
  • Step two. The compound is removed by a downstream particulate matter control device such as an electrostatic precipitator (ESP) or a fabric filter (FF), also referred to as a baghouse. Fabric filters are generally more effective (when combined with DSI) than ESPs, with respect to overall HCl reduction. For modeling purposes, EPA estimate a DSI system with a fabric filter is expected to achieve 90% removal of HCl, while an ESP only achieves 60% removal, although actual performance will vary by individual plant.

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