Ozone Generator System Instrumentation

As part of its supply of a complete ozone water treatment system, Spartan Environmental Technologies can recommend and supply the necessary instrumentation and controls. Below you will find a general discussion of ozone genrator system controls and instrumentation along with links to more specific issues:

Instrumentation for monitoring and controlling an ozone water treatment system varies with the nature of the application and the overall budget for such a system. Not all systems need to be fully instrumented, e.g. ozone generator manufacturers provide output curves which give ozone output as a function of percent power output and gas flow rate. These curves are fairly accurate and combined with a measurement of dissolved ozone in the aqueous phase should be sufficient for controlling the system. On the other hand, a ozone output monitor provides a check on ozone generator performance and allows for easy trouble shooting of the system in real time.

The links above will take you to web pages which will discuss in detail the specific category of instrumentation, the importance of the ozone measurements to the process and the type of instruments available. Below is a general overview of ozone system instruments.

The first area where instrumentation is required is in the preparation of the feed gas. This is most important in air fed systems or systems where air feed is used to add nitrogen (usually a few percent) to an oxygen feed ozone generator. While LOX is inherently dry, ambient air contains considerable amounts of moisture, at least with respect to ozone generator requirements usually -80 to -100 degrees F dew point). Therefore some provision needs to be made for monitoring the dryness of the air, if only indirectly. Moisture in the feed gas will reduce performance of the ozone generator and damage the equipment (see ozone system gas preparation).

In some cases it is important to monitor the output of the ozone generator. To do this one has to be able to monitor both concentration of the ozone in the gas, but also accurately measure the flow of the gas. While accurate gas measurement systems are not specific to ozone generation systems, high concentration ozone monitors are unique to these systems.

After the ozonated gas has been contacted with water, only a portion of it has been transferred to the aqueous phase (see web page on ozone transfer efficiency). A small portion will pass through the contacting system. In some cases this needs to be treated with an vent gas destruct system. To monitor the performance of such a system a low concentration ozone monitor is used in the vent of the ozone destruct system.

In most situations, some measure of the ozone in the aqueous phase is important. This can be measured directly in terms of mg/l of dissolved ozone or indirectly as an oxidation reduction potential (ORP). Instruments and wet chemical methods are available.

In terms of safety, precautions must be taken in case there is a leak of ozone. Ambient ozone monitors measure low concentration of ozone (down to a hundredth of a part per million of ozone in the air, i.e. 0.01 ppm). These devices can be linked to alarms or can be used to shut down the ozone generator.