Mercury Control and Mercury Stability in Byproducts - Mercury Emission and its Control in Chinese Coal-Fired Power Plants - page 119

production technique, form and supplier.
The three ACs, namely, AC(XK), AC(YK) and AC(MJ), were prepared by
steam activation from apricot shells, coconut shells and coal, respectively. These
activations were carried out at temperatures within 8001100 °C with the presence
of steam, and ACs prepared using this method only had hydrogen and oxygen
elements on their surfaces. On the other hand, AC(MZ) was generated from wood
by chemical activation using ZnCl 2 at a temperature of 600 °C. As a result, some Cl
and Zn elements remained on the surface of AC(MZ). All ACs were in powder form
except for AC(MJ), which was in granular form.

Table 5.7 Detailed information on ACs used in the experiments

Sorbent Raw material Production technique Form

AC(XK) Apricot shell Steam activation Powder

AC(YK) Coconut shell Steam activation Powder

AC(MJ) Coal Steam activation Granule

AC(MZ) Wood Chemical activation Powder

The surface physical characteristics of ACs were determined by Autosorb/1/C.
The surface chemical compositions of ACs were analyzed using a JEOL JEM/2010
electron microscope with INCA energy dispersive X-ray microanalysis. The surface
physical characteristics of AC(XK), AC(YK), AC(MJ), and AC(MZ) are shown in
Table 5.8. A continuous emission monitor (CEM) of DM/6A/MS/1A for mercury
speciation was used in the experiments.

Table 5.8 Surface physical characteristics of ACs

Specific surface area
(m 2 /g)

Pore volume
(cm 3 /g)

Micropore volume
(<20Å) (cm 3 /g)

Particle size
(mm)

Porosity
(%)

Sorbent

AC(XK) 1070 0.81 0.48 0.08 57

AC(YK) 846 0.48 0.38 0.08 43

AC(MJ) 791 0.41 0.37 1.5 34

AC(MZ) 1450 0.94 0.72 0.09 67

AC(MZ-T) 1218 0.71 0.58 0.09 62

Prior to the adsorption of Hg 0 , AC was placed on a fixed bed reactor, and sample
gas was adjusted to the desired flux in the bypass. All the experimental projects are
shown in Table 5.9. Every kind of powder AC sorbent was controlled at about 0.05
g (the height of the adsorption column was about 2 mm) except for AC(MJ), which
was about 0.10 g (the height of the adsorption column was about 2.5 mm). Ad-
sorption temperatures were all maintained at 130 °C. Initial Hg 0 concentrations
ranged from 13.7 to 19.4 g/(N·m 3 ). For each project, the total flux was controlled
at 1 or 1.3 L/min using a mass flowmeter.