Mercury Control and Mercury Stability in Byproducts - Mercury Emission and its Control in Chinese Coal-Fired Power Plants - page 108

adsorption efficiency curves of Hg 0 by lime on the two kinds of simulated flue gas
are shown in Fig. 5.4. The existence of SO 2 was favorable for lime adsorbing Hg 0 .
Based on experiments of Hg 0 adsorption by hydrated lime and lime, chemical
adsorption was found to be the key in the process of Hg 0 adsorption by cal-
cium-based sorbents. SO 2 , improved Hg 0 adsorption by calcium-based sorbents
through the chemical adsorption mechanism.

0.6

no SO
800 ppm SO

100

0.5

90

0.4

0.3

80

0.2

BL
800 ppm SO 2

70

0.1

0.0

60

0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35

Time (min) Time (min)

(a) (b)
Fig. 5.4 Hg 0 adsorption by lime on two kinds of simulated flue gas

Hg 0 adsorption ability of MFC
MFC is a mixture of fly ash LFA1 and lime with a mass ratio of 3:1. Adsorption
experiments were conducted on two kinds of simulated flue gas: 1) BL and 2) BL
added with 800 ppm SO 2 . Other conditions were the same (Hg 0 concentration: 21.5
g/m 3 ; temperature: 125 °C; flow: 1 L/min). The adsorption kinetic and adsorption
efficiency curves of Hg 0 by lime on the two kinds of simulated flue gas are shown in
Fig. 5.5. The existence of SO 2 was favorable for MFC adsorbing Hg 0 .
The three kinds of calcium-based sorbents, namely hydrated lime, lime and
MFC, had higher adsorption capacities and absorption efficiencies in flue gas with
SO 2 . Calcium-based sorbents are widely used as flue gas desulfurizers, indicating a
certain ability for Hg 0 removal. A combined removal technology of SO 2 and Hg 0
through injection of calcium-based sorbents can be considered.

(a) (b)
Fig. 5.5 Hg 0 adsorption by MFC on two kinds of simulated flue gas