The Ozmotics Insider

Ozone is a very active form of oxygen. It is formed when the oxygen ( O2 ) molecules are broken down to oxygen atoms ( O). Oxygen atoms ( O ) in turn react with other oxygen molecules ( O2 ) to form ozone molecules (O3).

The simplified formula for the process is:

O2 + energy = 2 O1

2 O1 + 2 O2 + energy = 2 O3

Is ozone found in nature?

Ozone is indeed found in nature! In nature ozone is formed by lightning (largest source of naturally generated energy) and the oxygen in the air. In fact, ozone is considered to be mother nature’s air freshener as it’s that fresh smell that’s in the air after a thunder and lightning storm.

Ozone is also found in the upper stratosphere and is the main shield protecting the Earth from harmful UV radiation. Without ozone more UV radiation would reach the Earth’s surface causing the irreversible damage and harm to all living organisms exposed.

If ozone is that good for the environment why we don’t we breathe it rather than oxygen?

Ozone cannot be inhaled directly by humans, animals or any air breathing organism. The concentration of ozone that is found naturally in the lower atmosphere (where we live and breathe) is very small. Additionally, ozone is very unstable and it reverts quickly to oxygen by the reverse process through which ozone molecules were created. The ozone decomposition formula can be represented simplified as:

2 O3 = 3 O2

Is ozone technology a new technology?

Ozone has been used for centuries to treat drinking water. The first water treatment plant that used ozone to purify the water was built in Netherlands in 1893. Nice (France) was the first large city to use ozone to treat their drinking water. Los Angeles, California has the largest modern day water treatment facility using ozone technology to treat around 600 million gallons of water each day.

Where else is ozone used?

The applications of ozone span a variety of applications and industries.

Used as an alternative for chlorine and bromine in swimming pools, ozone is a very effective disinfectant, which even prevents the formation of chlorine and bromine byproducts.

For soil remediation, ozone has been used to clean up sites containing a variety of soil contaminants, including oil and fuel.

Ozone is an effective medium in controlling microbiological growth in cooling towers.

A major problem in cooling tower water treatment is legionella (legionnaires disease). In the prevention and control of legionella causing microbes, ozone has taken an eminent roll. The specific characteristics of the ozone disinfectant make sure it gets the job done where others fail.

Ozone injected to a cooling tower will also aid in the prevention of the formation of algae thus reducing fouling and increasing heat-transfer efficiency.

The benefits of ozone within the cooling tower applications are not only environmental in nature but are also helping reduce the cost of the operating and maintaining the cooling tower infrastructure therefore improving the overall bottom line.

Following is information about a few of the other applications and industries where introduction of the ozone is of great benefit:

- Aquaculture
- Agriculture
- Bottling
- Disinfection
- Electronics
- Farming
- Winery Sanitation
- Pharmaceutical
- Food Processing and Preservation
- Hydroponics
- Laundry
- Pools and Spas
- Hospitals
- Soil Remediation
- Wastewater Treatment

How is ozone generated?

To make the ozone in the large enough quantities and the high enough concentration to be useful for industrial and commercial processes the more efficient way of generating the ozone is required.

One of the most common and economical ways of generating large quantities of the industrial ozone supply is using a corona discharge (forcing the air through narrow gap in presence of high power energy field (corona discharge).

The process of ozone generation via the corona discharge can be described in two steps:

First, the feed air required to generate ozone must have the nitrogen and other trace elements removed since the air we breathe contains only about 21% oxygen and as much as 78% of nitrogen.

The oxygen concentrator removes nitrogen from the ambient air leaving almost pure oxygen to be feed to the ozone generator.

This process is by far more economical than using chemicals that need to be hauled from off-site and stored on-site until the time they are ready to be used. Ozone is generated on-site and on demand therefore eliminating the transportation and storage costs.

Since there is no residue (any residual ozone not used by the process will revert back to the more stable oxygen form without any additional requirement or intervention) ozone technology is very eco-friendly (creates virtually no pollution).

I need more information about using the ozone. Who I can contact?

If you require additional information about the ozone technology, engineering and design of the turn-key ozone injection skid or need help sizing a unit please contact your Ozmotics representative at 1-877-386-3763.

Many configurations had been developed and tried and there may be further variations in the design of a turn-key ozone injection skid but in general the principle is fairly similar. Here we will attempt to outline the major components of the system.

Ozone injection skid – The process explained:

Step 1 – The Air Dryer

Using the corona discharge ozone generator and the oxygen concentrator (oxygen fed  ozone generator), the ozone injection skid typically follows the line process by which the ambient air is first circulated through the air dryer (the ambient air must be sufficiently dry and free of moisture in order to be used as a feed for the oxygen concentrator).

Step 2 – The Oxygen Concentrator

The Pressure Swing Adsorption (PSA) oxygen concentrator is commonly used to generate the high concentration oxygen feed that is required for the production of the ozone. To learn more about the pressure swing adsorption principle and understand how the PSA concentrator is used to efficiently and economically purify and concentrate the oxygen from the ambient air we invite you to read this article:

http://www.ozmoticsinsider.com/2008/10/pressure-swing-adsorption-psa-%e2%80%93-the-typical-layout-of-the-psa-oxygen-concentrator/

It is recommended to plan for the future and always install the larger oxygen concentrator unit than the immediate demand of the ozone generator equipment. While with some insightful planning and design (building a modular rack that can hold multiple ozone generator units) one can make the system expandable for the future growth and demand if the oxygen concentrator cannot produce enough oxygen gas feed as required by the expanded system, the entire concentrator will need to be replaced. Therefore it is always better to plan for a larger oxygen concentrator unit than what the immediate ozone generator input requirement directs.

Step 3- The Ozone Generator

The corona discharge generator is typically recommended for higher capacity ozone production since it can produce more ozone at a higher concentration compared to UV ozone generators. The corona discharge ozone generator is also typically smaller and more compact therefore more practical to use in the engineering design of an ozone injection skid.

The modular design is highly recommended for the planning and integration of the ozone generator meaning that multiple smaller capacity ozone generator units are preferred over a single larger capacity ozone generator unit.

By installing high quality ozone generators in multiple unit configurations, even if the single ozone generator cell is to fail, the other cells will still continue generating the ozone therefore allowing for the uninterrupted and continued ozonation operation.

Step 4 – Static Mixer and Venturi Injector

The efficiency of ozone to react with the water or other intended substance is strongly correlated with the contact area between the ozone and the substance you’re treating.

For aqueous ozone injecting applications (injecting the ozone in water or other liquid solutions), two methods are commonly used. The first method using an air stone diffuser will generate larger ozone gas bubbles therefore decreasing the available contact area of ozone to water. As such an air diffuser is not recommended in the design of the ozone injection system.

The Venturi injector is capable of diffusing the ozone gas as a much smaller bubbles therefore cumulatively increasing the contact area of ozone to the water or other liquid medium where ozone is to be injected. As such more ozone is used in the process and less residual ozone ends up escaping the system therefore lowering the production demand as well as the size of the ozone destruct equipment (used to destroy any escaped ozone from the contact chamber).

Step 5 – Contact tank

The ozone is typically mixed with water in a higher concentration than required (concentrated mix) and let to dissolve inside a contact tank. The contact tank will usually be designed with the obstacles (baffle) to allow the water to flow longer inside the tank before it exits and therefore allowing higher concentration of ozone to be dissolved in the water or other liquid used as the solvent.

Step 6 – Ozone destruct unit

Ozone destruct unit is used to destroy any unused ozone escaping from the contact tank. The destruct unit is usually a chamber in which a catalyst is packed (a catalyst will help break out ozone back into the oxygen before it is vacated to the outside of the contact tank. To ensure that no moisture enters the catalyst chamber, a water trap is typically installed in between the contact tank and the ozone destruct unit (to trap and collect any moisture escaping from the contact tank.

Step 7 – Ozone mixing chamber

The ozone mixing chamber is typically an external tank where the untreated water is mixed with the water from the smaller contact tank (where the higher than required concentration of ozone is dissolved to create a concentrated mix of water and ozone).

By mixing the high concentration of the dissolved ozone from the contact tank with the untreated water the diluted equilibrium of the desired ozone concentration is achieved in the entire body of the water (or other liquid to be ozonated). By increasing or decreasing the flow of water from the contact tank, the concentration of the ozone in the mixing chamber can be achieved.

Step 8 – Ozone Injection Skid Architecture Design (Conclusion)

This two step approach (ozonating only the part of the entire flow to a higher concentration and than mixing the high concentration of the ozonated liquid with the main body of the liquid to be treated), is far more economical than utilizing the single step inline ozonation where the entire body of the water (or other liquid to be ozonated) is ozonated. By requiring to ozonate only a portion of the flow to be treated, the size and capacity of the infrastructure (pumps needed to maintain the flow and pressure, injectors, pipes carrying liquid, etc.) is greatly reduced while still being able to treat the entire flow in general. The savings in the material are complimented by the savings in the real estate needed to install the ozone injection equipment (much smaller skids comparing to the similar capacity inline ozone injection skids).

The description offered in this article is a simplified description of the principle used to inject the ozone into the water or other liquids to be treated. The complete turn-key ozone injection skid has many more components than what has been explained in this article. Pumps, dissolved ozone monitoring probes, ORP meter, safety monitoring probes (to detect any accidental leak of ozone out of the skid, etc. can be further found inside the engineered turn-key ozone injection skid.

If you require additional information on the engineering and design of the turn-key ozone injection skid or need help sizing a unit please contact your Ozmotics representative at 1-877-386-3763.

In order to yield the higher volume ozone output typically required for the industrial ozone applications, your ozone generator must be designed to accept a gas feed containing a significantly higher concentration of oxygen than what is readily available om the ambient air.

Since the typical composition of ambient air is 21% oxygen and 78% nitrogen, the most economical way to increase the concentration of oxygen in ambient air is to remove the nitrogen component from it.

As a side benefit of removing the nitrogen from the ozone generator gas feed source, the nitrogen oxide and the nitric acid byproduct is also removed effectively reducing the amount of maintenance and scheduled service work typically required to remove such byproducts from inside the ozone generator corona discharge chambers.

The Pressure Swing Adsorption (PSA) Process

The PSA oxygen process uses a special material called zeolite to remove the nitrogen from the ambient air. Zeolite is used as it absorbs the nitrogen when subjected to a high pressure while releasing the absorbed nitrogen when the pressure drops.

The PSA process works by feeding the ambient air into a pressurized chamber containing zeolite. The nitrogen is absorbed by the zeolite while the oxygen is further passed through to the storage tank. When the zeolite is saturated where it can no longer effectively absorb the nitrogen, the chamber is depressurized. When the chamber is in the depressurized state, the nitrogen is released by the zeolite medium and vacates the system. The chamber is than re-pressurized and the cycle is repeated over and over generating purified oxygen for the oxygen fed ozone generator or any other application requiring the high purity oxygen gas feed.

Because of this simple design principle the PSA generators require very little maintenance and as such are a favorite choice for the on-site commercial and industrial oxygen purification process (the oxygen is purified on-site versus transported from outside in bottles therefore lowering the total operating cost of the process).

PSA Oxygen Concentrators and Ozone Generators

PSA Oxygen Concentrators usually go hand-in-hand with any ozone generator application where the gas feed is oxygen and not ambient air.

The output of the PSA oxygen generator is measured in the SCFH (standard cubic feet per hour). While the overall principle remains the same for all manufacturers, different manufacturers will use different designs resulting in different footprints as well as different capacities from one manufacturer to another as well as from one model to another.

To select a proper oxygen concentrator for your ozone generator application you will need to know the requirements of your ozone generator. It is typically recommended that you size your oxygen concentrator slightly larger than the current intake requirement of your ozone generator. While ozone generators can be engineered to be expandable (modular design, simply add extra ozone generator unit to your application), expanding the production capacity of the oxygen concentrator is a much harder task to accomplish and usually requires replacing the entire oxygen concentrator assembly.

If you have an application that requires an oxygen concentrator and need help sizing a unit please contact our Ozmotics representative at 1-877-386-3763.