Gas reburning-sorbent injection (GR-SI) is an emissions control technology for coal fired power plants which uses natural gas and calcium sorbents to reduce NOx and sulfur dioxide (SO2) emissions by 60 and 50 %, respectively. Gas reburning involves injecting natural gas into the boiler and reduces NOx by reactions involving hydrocarbon fragments produced in the process. SO2 is reduced since natural gas contains no sulfur. Additional SO2 reduction is provided by injection of a calcium based sorbent into the boiler furnace or downstream. The sorbent reacts with SO2 to produce calcium sulfate (CaSO4) which is captured by existing particulate collection equipment at the plant.
The preferred sorbent for GR-SI is calcium hydroxide [Ca(OH)2]. GR-SI requires substantial quantities of sorbent and will thus produce a significant market for calcium products.
A field evaluation of GR-SI is now in progress on two boilers in Illinois. The design engineering has been completed and construction is in progress. Start-up is scheduled for fall 1990.
This paper presents an overview of the GR-SI technology and the field evaluation project. Implications for the lime industry are also discussed.