Controlling Pollutants in Coal-Fired Power Plants in China - Mercury Emission and its Control in Chinese Coal-Fired Power Plants - page 5

The assumptions made by Wang, however, have yet to be proven by field test or
research. To date, the accuracy of such estimations still awaits validation. Thus, it is
important to study the mercury emission characteristics of the typical coal-fired
sources in order to establish a thorough, comprehensive, and accurate mercury
emission inventory of coal-fired power plants in China.

1.3.2 Mercury Emission Control Technologies in China

Coal-fired mercury control technologies have developed gradually in recent years.
Various mercury pollution control technologies used in coal-fired power plants are
presented in Fig. 1.3. Mercury pollution control technologies of coal-fired plants
can be roughly divided into three types: those done before, during, and after the
burning of coal.

Polishing filter
(TOXECON?)

Sorbent injection

Additives

Combustion
modifications

Scrubber

ESP/FF

Boiler

Coal cleaning

Stack

FGD
additives

SCR, Hg catalyst,
corona

Fixed adsorption
structures

Fig. 1.3 Mercury pollution control technical methods for coal-fired power plants
Examples of mercury control technology applied before burning include coal
washing, coal drying technologies, etc. Coal washing is an effective mode of re-
ducing Hg (g) emissions. In general, the mercury removal rate of flotation technology
is between the ranges of 21% 37%. This technology is applied depending on the

coal type, method of washing, separation technology, and mercury concentration in
coal [16] . The coal washing technology is a relatively old technology, whereas the
application of coal heating dry technology is fairly recent. Coal drying technology,
on the other hand, can remove about 70% of mercury in the coal before burning.
However, the rate of washed coal in China is still low and most coal-fired power
plants have not yet adopted the use of “washed” coal.
At present, studies of mercury control during burning have focused on the im-
provement of the combustion mode and additive combustion method. Research