How High Ozone Concentration Makes it Easier to Dissolve Ozone in Water

Interview conducted by Kris WalkerFeb 24 2014

AZoM talks to Arash Golshenas, Head of Research & Development at Primozone, discussing high Ozone concentration.

Could you provide a brief overview into Ozone concentration?

Ozone (O3) is formed when, by adding electricity, oxygen molecules (O2) are split into oxygen radicals (O1) and the oxygen radical tries to find other oxygen radicals (O1) or oxygen molecules (O2) to react with. These reactions occur inside the ozone generator and has two possible outcomes ie either oxygen (O2) or ozone (O3) is formed. Depending on the ozone generator construction one could improve the probability for the preferred reaction, ie formation of ozone (O3). The formation of oxygen (O2) will always be present hence the outgoing gas will always be a mixture (see step 3 in the Oxygen – Ozone – Oxygen cycle).

The ratio between the outgoing ozone and the oxygen is what constitutes the ozone Concentration. This is usually mentioned by one of two standard units,

• % wt, typically around 10 wt % meaning that the ozone gas is 10 percent of the total weight of the gas mixture.g/Nm3, mentioning the ozone weight of gas in comparison to the remaining volume to the gas, given a temperature and pressure.
• The conversions between both these units are given and they are pretty much the same.

The ozone amount, measured in g/h is the total amount of ozone produced every hour. Depending on the concentration of the gas mixture, the total amount of oxygen needed to produce ozone will vary. This means that if the concentration is doubled, the amount of oxygen feed to the system is reduced to half.
 

What is the process of dissolving ozone in water?

The process of dissolving ozone in water is optimized by maximizing the surface area between the gas and the water. This can be done by different means:

• Bubble diffusers
• Venturi injectors
• Static mixers

In other words, given a certain volume, very small gas bubbles have a bigger surface than one big bubble. This means that the small gas bubbles are dissolved better.

Maximizing the area is only able to dissolve ozone until the saturation limit is reached. If the application needs to dissolve more ozone, the saturation limit could be pushed further up by increasing the pressure. The pressure of the dissolution system has to be lower than the ozone generator discharge pressure for flow to go in the right direction.

Are there any challenges involved within the dissolving of Ozone?

When dissolving ozone there are two main challenges involved:

• Optimizing energy consumption of the dissolution system; The dissolution systems sometime use external pumps and these require energy to work. By having less gas to dissolve (high concentration) the system does not need to use as big pumps as previously.

Higher pressure improves the dissolution as well. This could be used to move the saturation limit of the water, to enable higher amount of dissolution than atmospheric pressure.

• Dissolving enough ozone, the amount of ozone that needs to go into the water to remove pollutants.

The Primozone® GM-series ozone generators are built on patented cutting-edge technology that enables ozone production with a very high concentration and at a very high outlet pressure.

Are there any other methods of increasing the dissolution of ozone in water?

Physically one can do two thing, reduced the amount of oxygen that needs to be dissolved (e.g having higher ozone concentration) or increasing the pressure of the dissolution system. Primozone is the market leader on both high concentration and high output gas pressure.

The dissolution system must have a lower pressure then the ozone generators to enable a gas flow from the generators to the dissolution system. But the saturation limit for the water is based on the actual pressure at the dissolution; hence the discharge pressure of the ozone generator is crucial.

Primozone specialize in providing the market with state of the art ozone generators, what are the unique capabilities of these generators?

The high pressure and high ozone concentration is used to increase the dissolution capabilities of the system. By having a better dissolution, one can reduce the total amount of ozone produced, hence saving energy.

Some dissolution system have an efficiency of 60-65 %, this will force the ozone generator to produced 50 % more ozone then the process really require. The Primozone ozone generator and dissolution systems will significantly reduce the excess ozone produced, hence enabling energy savings.

Another unique capability of the ozone generator is the ruggedness and that it is built to last. When having correct usage the system, the system does not need any service just a yearly oversight.

Primozone provides safe and customized solutions for water treatment, how can this be applied to removing high dosages of Pharmaceutical Effluent from Wastewater?

Primozone can help design the dissolution system that will enable ozone to remove pharmaceutical effluent from the wastewater. We can also provide the entire solution, from the oxygen system all the way to the dissolved ozone in water.

Primozone has during the last 3.5 years made extensive research into waste water treatment with ozone, together with Lund University. In our research we have been able to reduce the pharmaceuticals with 95 %. More information can be found at our website: http://www.primozone.com/municipal/pharmaceutical-residue
 

What are the challenges faced with removing organic dye compounds from wastewater?

The biggest challenge of removing organic dye compounds from wastewater is the amount of ozone that needs to be dissolved. This is an application where Primozone ozone generators come into good use.

The Primozone GM18 has a capacity of up to 1kg O3/h. how does this compare to the competition?

Primozone provides the same capacity units as most competitors. Our competitive advantage lies in the following features that the competitions doesn’t provide:

•   Highest ozone concentration up to 20 wt% - saves oxygen
•   Highest gas pressure - up to 2.2 bar(g) with maintained ozone concentration
•   Modular and scalable design
• Smallest footprint – very compact in size
• Energy efficient - up to 50% savings
• Leakage free design - made from only stainless steel and aluminum

About Arash Golshenas

Arash Golshenas is head of R&D at Primozone where he spearheads the development of new and existing products. Primozone is an ozone generator & ozone system supplier that is determined to change the way ozone is perceived and used in the global water market. Golshenas is also heavily engaged in product verifications and research into ozone applications and ozone system design.

Previously, Golshenas worked for 3 years at Gambro Lundia AB, where he was responsible for the implementation and coordination of a citrate/calcium anticoagulation system for acute dialysis care. Golshenas has a M.Sc in Engineering Physics and an executive MBA, both from Lund University.