Emissions flow inside of the pipe. A phenomenon occurs when the voltage through the
beads exceeds the insulating effect of the beads and millions of micro-discharges occur. The
duration of these discharges is measured in nano-seconds.8
The individual discharges cannot be
seen with the human eye, but the overall effect produces a silent glow. This effect will only
occur when the power source is alternating current (AC). DBD cannot be induced with direct
current (DC) power because the capacitive coupling of the dielectric necessitates an AC field.
In this environment, in addition to electrons flying about, atoms are being separated from
their molecules to become free radicals. Since free radicals are highly reactive, they quickly recombine with other atoms and/or molecules to form new compounds. Using oxygen as an
example, the normal state of oxygen is a molecule containing two oxygen atoms. Thus, it is
written as O2
. In a DBD field, the oxygen molecules splits into two atoms of oxygen, O + and O +
.
The elemental oxygen radical, being very reactive, will form ozone, O3
, when the radical oxygen-4-
atom reacts with a normal molecule of oxygen (O2
).
The oxygen radicals also react with other compounds. For example, oxygen radicals react
with carbon monoxide (CO) to form carbon dioxide (CO2
), sulfur dioxide (SO2
) to form sulfur
trioxide (SO3
), and nitrogen oxide (NOx
) to form nitric acid (HNO3
) in the presence of moisture.
Ozone will also react with small (2.5 micron) carbon particles (soot) to form carbon dioxide, and
reacts with elemental mercury (Hg) to form mercury oxide (HgO). Oxidizing elemental mercury
changes it from a vapor to a solid phase. Sulfur trioxide hydrolyzes into sulfuric acid, when
exposed to moisture. Depending on the concentrations of nitrogen and sulfur compounds, this
process is capable of producing significant amounts of mineral acids