Mercury Control and Mercury Stability in Byproducts - Mercury Emission and its Control in Chinese Coal-Fired Power Plants - page 120

Ta b l e 5. 9 Experimental project of Hg 0 onto activated carbon in N 2

Initial Hg 0 concentration
(g/(N·m 3 ))

Amount of
sorbent (g)

Adsorption
temperature (°C)

Flux
(L/min)

No. Sorbent

1 AC(XK) 0.0501 130 18.8 1.3

2 AC(XK) 0.0503 130 18.8 1.3

3 AC(YK) 0.0505 130 19.4 1

4 AC(YK) 0.0516 130 14.2 1.3

5 AC(MJ) 0.1002 130 16.9 1.3

6 AC(MZ) 0.0514 130 16.4 1

7 AC(MZ) 0.0508 130 14.2 1.3

AC(MZ-T) a 8 0.0500 130 16.9 1.3

AC(MZ-T) a 9 0.0507 130 13.7 1.3

a

: AC(MZ) has been treated by high temperature treating system

5.4.3 Hg 0 Adsorption by Four Commercial ACs in the N 2 Envi-
ronment

In order to estimate the influence of the surface characteristics of AC, Hg 0 adsorp-
tion studies on AC(XK), AC(YK), AC(MJ), and AC(MZ) were conducted on a
fixed bed reactor in the N 2 environment. The results indicated that the adsorption
process was only influenced by the surface characteristics of AC. The results also
reflected the impact of the surface characteristics of AC on Hg 0 adsorption.
Fig. 5.18 shows the Hg 0 adsorption by AC(XK) in N 2 environment. At the be-
ginning of the experiment, the initial Hg 0 concentration was 18.8 g/(N·m 3 ). The
outlet Hg 0 concentration fell about 5 min after the start of the experiment when the
gas flow was switched from the bypass to the fixed bed reactor. This was due to the
presence of air in the tube between the end of the fixed bed reactor and the entrance
of the CEM. About 1 min later, the outlet Hg 0 concentration in the tail-end gas rose
back to the initial concentration. This indicated that all the Hg 0 penetrated through
the fixed adsorption bed of AC(XK) in the N 2 environment. The results of the two
repeated experiments were almost the same (Fig. 5.18). Consequently, it can be
concluded that AC(XK) did not adsorb any Hg 0 when the Hg 0 -N 2 gas flowed
through the fixed bed. The experiments of Hg 0 adsorption by AC(YK) were con-
ducted with different initial Hg 0 concentrations (19.4 and 14.2 g/(N·m 3 )). More-
over, AC(YK) had no capability to adsorb Hg 0 in the N 2 environment (Fig. 5.19),
either.