Mercury Control and Mercury Stability in Byproducts - Mercury Emission and its Control in Chinese Coal-Fired Power Plants - page 130

5.4.5 Saturated Hg 0 Adsorption Experiments by ACs in Simulated
Flue Gas
Based on the obtained results, the adsorption process of Hg 0 by AC was found to be
the chemical adsorption in N 2 gas or in simulated coal-fired flue gas. The Hg 0 gas
was probably oxidized to Hg 2+ and adsorbed by AC. Thus, when the adsorption
capacity of AC for Hg 0 was close to the maximum, Hg 2+ could be detected at the
outlet of the adsorption bed. To further confirm the above-mentioned conclusions
and discover the mercury adsorption mechanism of AC, saturated Hg 0 adsorption
experiments using ACs were conducted in simulated flue gas.
5.4.5.1 Saturated Hg 0 Adsorption Experiments by AC(MZ) in Simulated Flue
Gas
The adsorption experiments were conducted by the bench-scale experiment system
with a fixed adsorption bed in the simulated flue gas (Fig. 5.1). The AC sorbent was
controlled to about 0.05 g (the height of the adsorption column was about 2 mm).
The heating temperature of the gas channel and the operating temperature of the
fixed adsorption bed were all kept constant at (130±1) °C. The Hg 0 adsorption
experiment by AC was divided into four steps, which were conducted continuously.
The time consumed for the experiment was about 60 h, as shown in Fig. 5.28.
Fig. 5.28 Hg 0 adsorption by AC in N 2 and in simulated flue gas
Step 1 consumed 16 min in total. Here, AC was first placed in the fixed bed
reactor, and the concentration of Hg 0 was controlled at 14.2 g/(N·m 3 ) with a total
flow of 1.3 L/min in the bypass. Through this step, a consistent and stable initial
condition was established.
In Step 2, the adsorption Hg 0 by AC was first conducted in N 2 gas. This step was
performed to investigate the adsorption between the surfaces of AC and Hg 0 . This
step was maintained for about 16 h and 33 min.