Fly Ash Carbon Separation and Ammonia Removal at Tampa Electric Big Bend

摘要

Separation Technologies,LLC(ST)operates fly ash beneficiation facilities,processingpoor quality fly ash into high quality pozzolanic material.ST’s triboelectric separationprocess reduces the carbon content of fly ash,producing ProAsh~R a consistent,low losson ignition(LOI)ash for use as a substitute for cement in concrete.Simultaneously acarbon rich product,EcoTherm~(TM) is created that can be returned to the utility forrecovery of the fuel value or to a cement kiln as both fuel and a source clinker material.ST also operates a process to remove excess ammonia from fly ash.In 2008,ST commissioned its newest and largest US fly ash beneficiation facility at theTampa Electric Company Big Bend Station in Florida.Two ST separators are installedto produce low LOI ProAsh~R.A first-of-its-kind third separator is used to furtherconcentrate the carbon to maximize the fuel value of the EcoTherm~(TM) and to maximizethe amount of ProAsh~R recovered.At Big Bend the ST ammonia process reduces the ash ammonia from average levels of～2000 ppm to<75 ppm to meet market requirements.Improvements in this secondcommercial installation of the ST ammonia system include higher rate capability,improved drying efficiency,and use of a catalytic system to recover heat by convertingthe liberated ammonia gas into nitrogen.The Big Bend facility,which will produce260,000 tons per year ProAsh~R includes a 25,000 ton dome for feed ash,a 10,000 ton silo for ProAsh~Rand a 6,500 ton silo for EcoTherm~(TM).ProAsh~R and EcoTherm~(TM) are produced with ST’s technology at eleven power stationsthroughout the U.S.,Canada and the United Kingdom.