In 2011, the EPA announced new Utility Boiler MACT limits. These limits included a maximum HCl emission of 0.002 lbs/MMBtu. Boilers must meet this limit as early as late 2014. Hydrated lime -- especially in conjunction with a baghouse -- is effective for controlling HCl (and HF).
Historically, hydrated lime scrubbing by dry sorbent injection has been used to control HCl in industrial applications including industrial incinerators and waste to energy facilities. The byproduct formed is calcium chloride.
2HCl(g) + Ca(OH)2 (s) -> CaCl2 (s) + 2H2O (g)
Mississippi Lime hydrated lime has been used to successfully mitigate HCl from full scale coal-fired Utility boilers. In systems that contained significant (>20ppm) or low (<5ppm) amounts of SO3 in the untreated flue gas, Mississippi Lime hydrate was able to reduce HCl levels below 1 ppm (or 0.001 lbs/MMBtu) at the outlet of the respective unit’s baghouse.
Contact Mississippi Lime if you would like more information on using hydrated lime dry sorbent injection for HCl mitigation.