Demonstration of Technology for Enhanced Mercury Control with SDA and CDS Units

摘要

Nalco has developed MerControl 6012 technology, a patented, non-halogenated, non-carbon breakthrough sorbent for the capture of mercury in flue gas for plants with SDA and CDS units. During the course of full-scale utility field testing in July 2011, it was discovered that the presence of a spray dryer absorber-fabric filter (SDA-FF) provides ideal conditions to realize the full potential and high mercury capacity of the material. In a recent demonstration, the non-carbon, non-halogenatedMerControl 6012sorbent was found to outperform brominated powdered activated carbon at lower feed rates. Additionally, its performance was further enhanced with the application of the mercury oxidant MerControl7895 technology on the coal. Furthermore, Nalco has shown that mercury emissions remained at low levels hours after sorbent injection was halted, and only began to climb after the fabric filter bags were pulsed. While in-duct application of sorbents is well known in the industry, the SDA provides an opportunity to apply the non-carbon, non-halogenated sorbent with the lime slurry feed. The product is applied as a liquid reducing capital requirements and handling concerns related to alternative mercury control technologies. This presentation provides details of a recent demonstration in which the patented, non-carbon, non-halogenatedMerControl 6012sorbent reduced mercury emissions well below MATS regulations on a full-scale utility boiler equipped with an SDA-FF. Its synergistic combination with MerControl 7895 oxidant, as well as comparisons with brominated activated carbon, will also be discussed.