Study of the Effect of FeCl3 on the Ignition Point of Coal
Qiaowen Yang, Dongyao Xu, Wei Li, Aiguo Cheng, Jia Cao, Liying Wang, China
University of Mining & Technology, P.R. CHINA
The combustion supporting alternate agent of three coals was selected by Thermal Gravity
Analysis (TG) in this paper, it has been found that FeCl3 plays great role on reducing the
ignition point of Guangxi Liang-coal, and FeCl3 could effectively reduce the ignition point
of Xinwen raw coal and Guangxi An-coal also. It also stated that FeCl3 has a good
combustion supporting action on the coal. At the same time, the relationship of FeCl3
amount and the ignition point of coal were inspected; the optimum amount of FeCl3 could be
got. We initially probed into the combustion supporting mechanism of FeCl3, during
combustion, the combustion supporting action of FeCl3 was the results of common action of
chloride and iron in chemicals; The combustion supporting action of FeCl3 was individually
achieved by reducing the ignition point of Volatile and Fixed Carbon.
Experimental Investigation and Theoretical Calculation on Effect of C12
on Mercury Oxidation in Coal Fire Combustion Process
Wei-Ping Pan, Songgeng Li, Quanhai Wang, Yan Cao, ICSET of Western Kentucky
University, USA
Mercury (Hg) from coal power plants has been identified as the hazardous air pollutant
of greatest public health concern. Hg in the flue gas occurs as three main forms: the
gaseous elemental mercury Hg(0), the gaseous oxidized Hg(2+), and particulate
mercury, Hg(p). Hg(2+) is water soluble, highly absorbable on fly ash and has a low
vapor pressure. Therefore, relative to Hg(0), Hg(2+) is more effectively captured in
conventional Air Pollution Control Devices (APCD) such as wet scrubbers (FGD),
fabric filters (FF) and electrostatic precipitator (ESP). However, Hg(0) is firstly
vaporized in the flue gas at higher temperature zone in combustor, followed by
thermodynamically favored oxidation process to major occurrence of Hg(2+) through
the homogeneous and the heterogeneous reaction routines at downstream flue gas pass
as temperature is cooled down. Thus, identifying the mechanism of mercury oxidation
in the downstream flue gas pass is very important to improve mercury emission control
efficiencies by APCD in the coal-fired boilers. Based on facts that HgCl2 is the main
Hg(2+) in coal-fired combustion process, as well as enormous previous studies on Hg
oxidation, it has been generally accepted that chlorine-containing species are the most
important factor on the Hg(0) oxidation in coal-fired flue gas. Chlorine is evolved
during coal combustion primarily as hydrochloric acid (HCl), less chance as chlorine
molecule (Cl2) through the Deacon reaction under fly ash available conditions.
However, the possible concentration of Cl2 is still much higher than request by the Hg
oxidation process. Moreover, the flue gas chemistry may dramatically impact this
oxidation process by the intermediate reactions to affect production of chlorine ion,
which is more active in the Hg oxidation process. In this work, isolated effects of Cl2
and HCl or their effects including other flue gas species on Hg oxidation under a
largely varied temperature window were investigated in a special designed multi-phase
flow reactor. A thermal-dynamic and kinetics calculation is used to explore the maxim
Hg oxidation rate and possible reaction mechanisms.
Transformation of the Fe-Mineral Associations in Coal during Gasification
Frans Waanders, North-West University, SOUTH AFRICA
John Bunt, Sasol Technology, SOUTH AFRICA
The mineral matter associated with coal undergoes various transformations during the
coal gasification process. Optimisation of the gasification process is necessary in the
coal to liquids technology. The principle aim of this investigation was to determine the
changes that the Fe-containing minerals and mineral associations undergo during
gasification used, a gasifier dissection was undertaken on one of the Sasol gasifiers. Detailed
characterisation profiles of various properties of the coal were undertaken after a
commercial-scale gasifier was shutdown for routine maintenance of which the
Mössbauer spectroscopy technique will be described here. Representative samples
from the gasifier were extracted after sufficient cooling was done to allow the safe
turn-out of the gasifier. In the coal samples that entered the gasifier, pyrite was the
abundant Fe-containing mineral, whilst the pyrite changed gradually to form, in
conjunction with the SiO2 and Al2O3 present in the coal, a Fe-containing glass and
hematite at the bottom, or ash grate of the gasifier.of coal. Due to the complexity of the counter-current coal-gas process