Principle of Multi-Pollutants Removal Technology in Flue Gas by Ozone - Simultaneous Multi-Pollutants Removal in Flue Gas by Ozone - page 39

3) Organic polymer material
Wang et al . [34] introduced a dielectric tube with an internal diameter of 69 mm
and thickness of 12 mm, which was made by a kind of organic-polymer plastic
with excellent properties (including a long duration at 145 °C, strong electrical
insulation, extensibility, size stability, chemical corrosion resistance,
self-extinguishing and flame-retardant abilities, non-toxicity, and so on). Zhu et
al . [35] suggested that with glass replaced by polycarbonate in the dielectric and
using the air source, both the ozone production rate and mass concentration in
each dielectric tube could reach relatively high levels, in addition to low power
consumption and economical operation. With maintaining the operational voltage
below 6370 V and simultaneously increasing the discharge frequency, the
ozone-generating tube degradation process postponed, developing a trouble-free
service lifespan exceeding 8000 h.
4) Glass
With the development of the glass material and sintering technology, in the
recent years glass has been used as the dielectric material in many ozone
generators.

2.3.4 Mixed Discharges

A number of improvements in increasing the ozone production efficiency have
been achieved by combining two types of discharges. These combined patterns
include surface and silent discharges, surface and corona discharges, glow and
silent discharges [36-40] .
Nomoto et al . [41] generated ozone by using a combination of silent and surface
discharges. It was found that using a mixed gas source (i.e., 80% N 2 + 20% O 2 ),
the ozone yield reached 110 g/(kWh) and was approximately two times of that
only with silent discharge. Moreover, when using oxygen as the gas source, the
combined discharge pattern generated a maximal ozone yield up to 274 g/(kW h),

equaling to approximately 2.5 times of that only with silent discharge.
Ma and Qiu [42] designed a silent-surface hybrid discharge ozone generator by
using solenoid and metal electrodes. Experimental results showed that with pure
oxygen as the gas source, the ozone yield rate achieved 295 g/(kWh) when the
output ozone concentration was relatively high at 1.3 mg / L. In 1999, Hakiai et

. [43] reported the ozone generation and distribution characteristics in an ozone

al