Environmental Engineering Reference
In-Depth Information
14.3 Results and Discussions
14.3.1 Materials Characterization
In order to obtain relevant input data for the simulations, we investigated three
probes, named as A, B, and C, consisting in samples of ash resulted from the
combustion of different wastes, collected monthly from filters of Pro Air Clean
Timisoara hazardous waste incinerator, within a period of 3 months. The inciner-
ation procedure is based on the complete burning of waste at 850-1,000
C and
postcombustion at temperatures between 950 and 1,300
C of the resulting gas,
followed by sudden cooling, a process that ensures the complete destruction of
dioxins, furans, and other toxic components resulting from special waste incinera-
tion. The plant allows any type of solid waste incineration (excluding radioactive
wastes) in the inferior chamber, and liquid waste incineration such as pesticides,
solvents, and oils through direct injection in the postcombustion chamber. Although
the technological process is automatic and developed for advanced control of
emissions in the atmosphere, it cannot filter and control the nanoparticle contained
in flue gas [
1
,
3
]. These probes were analyzed from dimensional and dielectric point
of view.
14.3.1.1 Dimensional Analysis
For dimensional characterization, we prepared for each of the three probes a
mixture of 5 mg ash in 100 ml distilled water at room temperature, and put it to
rest for 20 min, in order to decant the microparticles. Then we collected the
remaining slurry liquid and analyzed the particle size/concentration distribution
using a Nano Sight LM 10 nanoparticle visualization system. This high-
performance device determines the size distribution and the number of nanoparticle
in polydispersed and heterogeneous systems using nanoparticle-tracking analysis
method. Figure
14.9a
reveals a sample video frame with suspended nanoparticle,
while Fig.
14.9b
illustrates the particle size/concentration distribution for probe
A. The distribution diagram indicates that it contains four significant groups of
nanoparticle, having sizes of 55 nm, 100 nm, 155 nm, and 275 nm, respectively.
Figure
14.10
illustrates the size/concentration distribution of particles for probe
B (Fig.
14.10a
) and probe C (Fig.
14.10b
), after a decantation time of 20 min. The
distribution diagrams indicate four significant groups of nanoparticle, with sizes of
44, 67, 109, and 180 nm in probe B, and five significant groups of nanoparticle
having sizes of 40, 60, 102, 138, and 175 nm in probe C.
These analyses show that the gas resulting from the combustion of waste
contains nanoparticle. Recall that these nanoparticles are only those that probably
were attached to larger particles, and stocked during the mechanical filtering
process. They are, however, relevant to our study because the results suggest the
existence of a much larger quantity of nanoparticle in the combustion waste gases
