Mercury Speciation Transformation During Coal Combustion - Mercury Emission and its Control in Chinese Coal-Fired Power Plants - page 49

Transformation in Flue Gas

From the simulation results shown in Figs. 4.17 to 4.41, the value of was
between 1.53 and 1.91, and the average was 1.78. This value is similar to that given
in the literature [14, 4] .
2) Reaction order and reaction rate constant K
The results shown in Figs. 4.17 to 4.41 determined the reaction rate K 1 of the
pseudo -level at a given HCl concentration and reaction temperature, which were
summarized and shown in Table 4.8. The reaction order of reaction rate to HCl
and the apparent reaction rate constant K between mercury and HCl could be ob-
tained from these results.

Table 4.8 Reaction rate K 1 of the pseudo -level at a given HCl concentration and reaction tem-
perature
T (K) C HCl (ppm) K 1 T (K) C HCl (ppm) K 1

373 20 0.00765 773 80 0.07024

373 40 0.0107 773 100 0.1073

373 60 0.01378 973 20 0.0624

373 80 0.03939 973 40 0.09049

373 100 0.03434 973 60 0.1078

573 20 0.0258 973 80 0.1280

573 40 0.02514 973 100 0.1691

573 60 0.07694 1173 20 0.1264

573 80 0.066 1173 40 0.1715

573 100 0.0743 1173 60 0.2290

773 20 0.0364 1173 80 0.4034

773 40 0.03759 1173 100 0.4173

773 60 0.07951

Based on the kinetic model, a straight line could be drawn from the logarithmic
of the pseudo -level reaction rate constant K 1 to the logarithmic of HCl concen-
tration. could be obtained from the slope, and K could be obtained from the linear
intercept. The results are shown in Figs. 4.42 to 4.46.
From the simulation results shown in Figs. 4.42 to 4.46, the range of was
between 0.76 and 0.88, and the average was 0.79. In this way, the specific form of
the kinetics formula of the total combination reaction of mercury and HCl in the
flue gas with other compositions was established.

-3.2

-3.6

-4.0

-4.4

-4.8

2.8 3.2 3.6 4.0 4.4 4.8

ln C HCl
Fig. 4.42 and K when T ˙ 373 K ( =0.88; K =0.000499; r 2 =0.861)