Mercury Speciation Transformation During Coal Combustion - Mercury Emission and its Control in Chinese Coal-Fired Power Plants - page 51

Transformation in Flue Gas

-4.5

-5.0

-5.5

-6.0

-6.5

-7.0

-7.5

-8.0

0.001 0.002 0.003

1/ T
Fig. 4.47 Energy activation and pre-exponential factor ( E a =12787.54 J/mol, A =0.029858
(g/m 3 ) -0.78 · ppm 0.21 · s -1 , r 2 =0.985)

Based on the simulated results shown in Fig. 4.47, E a =12787.54 J/mol and
A =0.029858 (g/m 3 ) -0.78 · ppm 0.21 · s -1 . This value was similar to the literature, and the
values were in the same order of magnitude. Senior [1] applied reaction rate constants
for two temperatures to derive an energy activation of 15 kJ/mol for mercury and
HCl.
Error analysis between experimental and model simulated results
To examine the accuracy, model simulated results were compared with the ex-
perimental results in the same conditions with 40 ppm HCl, 6.478 g/m 3 mercury,
7% O 2 , 13% CO 2 , 1200 ppm SO 2 , 800 ppm NO, and N 2 balance gas at a temperature
of 300 °C. The comparison result is shown in Fig. 4.48 and Table 4.10.

5.0

Experimental value
-- Calculated value

4.5

4.0

3.5

3.0

2.5

2.0

1.5

23456789 0

Time (s)

Fig. 4.48 Error analysis between the experimental and simulated results ( C HCl ˙ 40 ppm and
T =300 °C)

The small differences between the simulated and experimental results might be
attributed to two aspects. First, the uncertainty of experimental data meant that there
were complex procedures for gas distribution and instrument adjustment during the
test. Thus, a variety of experimental errors and manual errors might have been
generated. Second, the model analysis was only a total combination experimental
dynamic model, and a variety of errors were included, thereby causing the differ-
ence between calculated and experimental results. However, based on the com-
parison of the calculated and experimental values, both results showed a high de-
gree of similarity.