Effective mercury sorbents
Activated carbon sorbent injection has enabled many cement plants to minimise mercury emissions from their operations. To ensure effective mercury control understanding the sorbent properties critical to mercury removal is key. By John Satterfield, Cabot Norit Activated Carbon, USA.
Figure 1: Plant A – fuel Hg content: 25-53ppb
Reducing mercury emissions by activated carbon sorbent injection (ACI) has been thoroughly demonstrated as a successful strategy at a growing number of cement plants. Not only is capital cost and process impact low compared to other potential control methods, but ACI is a ‘tunable’ control strategy which can be rapidly adjusted to handle shifts in input mercury concentration from highly variable raw mix components (eg, limestone) and fuel (eg, coal, petcoke, tyres). In light of this, understanding what sorbent properties are critical to performance and how new generations of sorbents have combined improvements to fundamental properties with novel chemistry is central to an effective mercury control strategy.
