|dc.description.abstract||Ozone (03) is used as a steriliser of air and water, but the nitrogen oxides (NOx) are harmful
to man and the environment. Ozone generators excite electrons to higher energy levels so
that O3 and NOx can be manufactured from oxygen and nitrogen in the air feed.
The factors that influence the NOx production in domestic ozone generators, in particular
Sterizone ozone generators were investigated, so that their design, operation and
marketability could be improved.
Sterizone ozone generators are designed with an exceptionally fast change in electrical
field of 3 x 10xy8V mm-1 s-1 with the aim of optimalising ozone production and decreasing NOx
production. In this study it was found that Sterizone does produce NOx.
After optimalising the analytical methods, the influence of the following reaction conditions on
the production of O3 and NOx by Sterizone was investigated:
1) Feed of synthetic air
2) Water vapour pressure of the feed gas
3) N2/02 ratio of the feed gas
4) Contaminants in the air feed
5) C02 in the air feed
6) Change in the frequency of the pulses
7) Temperature of the feed gas
It was found that the Sterizone unit showed comparable properties with other ozone
generators. High temperatures lower the ozone production so that the air feed must remain
sufficiently high to prevent overheating which leads to high N0,/03 ratios.
The ozone production of Sterizone is dependent on the quality of the environmental air. Air
humidity and contaminants like diesel fuel, ethanol, paraffin and xylene vapours lead to a
drastic decrease in O3 production. Carbon dioxide on the other hand causes a much smaller
decrease in ozone production.
No reaction conditions were found that led to a significant lowering of NO, production.
The determination of nitrogen oxides was problematic and better analytical methods should
be developed. It is recommended that an investigation is done into the possibility of removing
the nitrogen oxides by means of an external filter or decreasing the product by means of
ultraviolet radiation. The development of a more comprehensive theoretical model for the
ozone formation processes will be beneficial to the optimalisation of ozone generators.||