Clean Dry Air

Water content needs to be nearly zero for ozone generator feed gas.

Long term, reliable operation of an ozone system depends largely on clean, dry air. Unless you have liquid oxygen (LOX) as an oxygen source, your ozone will be generated from the oxygen found in ambient air. The air around us contains dust particles, and lots of water vapor. One cubic meter of air on a hot humid day can contain up to 30 grams of water. Even a gram of water vapor in a cubic meter of air (dew point -5 deg. F) will inevitably lead to failure of the ozone generating equipment. We need to get another 9/10 of a gram of water out to keep an ozone generator in good shape.

Water content in air is most commonly measured in terms of dew point. Dew point is the temperature at which water vapor condenses into liquid. When a mass of air cools down to very cold temperatures before water condenses, it indicates that there is not much water vapor in the air. The graph shows that dew point is not linear in relation to the amount of water vapor in the air. It is easy to see that the water content gets close to zero at about -50 degrees F. Large ozone systems operate with feed gas between -100 and -60.

An air filter and desiccant air dryer is often used to clean and dry the air for a small air-fed ozone system. The desiccant material absorbs moisture from the air as it passes through. When the desiccant becomes saturated, air flow is switched to a second chamber of desiccant material while heat is applied to the first to drive the water from the material in the first chamber. The processes switches back and forth, effectively dries the air to a dewpoint of -40 deg F. This is a cost effective level of dryness for small ozone systems.

Ozone systems that use an oxygen concentrator are able to take even more water out of the feed gas. The first line of defense will be the air filter for the air coming into the air compressor used for your ozone system. This filter will remove particles of dust that eventually wear out the compressor as well. The compression process also serves to remove much of the water when the hot compressed air cools forming water droplets that can be removed with a coalescing filter. A compressor with a means to cool the compressed air can bring the dew point from 60 to 40 degrees. This compressed air is forced through the zeolite sieve beds of and oxygen concentrator. The zeolite quickly absorbs the Nitrogen and remaining water vapor. As the oxygen concentrator cycles, the Nitrogen and water vapor is exhausted, leaving 93% oxygen with a dew point from -60 to -100 degrees F.  The oxygen concentrator works well as long as water vapor does not build up or condense in the sieve beds. They will not work well when the compressed air has a dew point above 40 degrees or the sieve material absorbs moisture during down time.

Oxidation Technologies provides sales, service, and system design of gas preparation equipment for ozone systems.  

Flow-Meter Quiz

Efficient and accurate ozone production requires accurate measurements of gas flow rates. The rota-meter style flow-meter is a simple, robust, and accurate way to measure the flow of gas or liquid.   The only moving part is a metal ball (float) within a tapered transparent tube.  As flow rate increases, the ball rises.  Try out this quick, one-question quiz to test your ability to read this instrument.

One limitation to this device is its inability to factor in gas pressure in a direct reading.  Gas under pressure is squeezed together so more gas is able to flow past the ball than it reads.  Some flow-meters are calibrated for a specific gas pressure.  Such meters are accurate only at that pressure.  This limitation is easily overcome with a simple calculation.   You can calculate an accurate flow rate at any pressure when you  know the gas pressure of the gas flowing through the meter.  How did you do on the quiz?  If you haven’t tried it yet, check out our calculator page for better chance of getting it right.

 

Tools for ozone monitor calibration and bump-testing

Ozone monitors and sensors should be calibrated every 6-months to 1-year. This calibration can be done by our technicians to a NIST traceable standard. However, if this is something you prefer to perform on-site we have a few tools you can use to perform calibrations on-site, or bump-test your ozone monitor between calibration intervals.

Learn more about ozone monitor calibration on our main website HERE.

Model 306 Calibration Source

The Model 306 Calibration Source is a UV based ozone source that is portable and easy to use.  This device will provide a known quantity of ozone gas in a sample stream of 3 LPM.  Three usable settable ozone ranges are available to choose from for calibration.  This will allow the calibration of most ozone sensors that have a calibration adapter or a flow-cell where gas can flow to or through the sensor for calibration. This device requires no zero air cylinder and can use ambient air for ozone sensor calibrations.  The accuracy of this device is 2% which is superior to any other portable calibrator available on the market.

Calibrate Ozone monitors with the Model 206
306 Calibration Source

A23-14 Ozone Calibrator

The A23-14 Ozone calibrator is used to calibrate your ozone sensors. This device creates a known level of ozone with the factory calibrated ozone generator. Easy to use, and portable this unit can be carried to your ozone sensor.  Accurate to within 5-10% depending upon the application.

A23-14 Ozone Calibration Kit for field calibration of ozone sensors
        A23-14

Ozone Puffer

The ozone puffer is a simple to use tool to bump-test ozone sensors. Portable and battery powered, this is the easiest method to quickly bump-test your sensor between calibration intervals.  Battery powered unit requires no power cord and is completely portable.

Bump testing is a great method to ensure your sensor is responding to ozone when necessary. Bump testing is not a replacement for calibration. However, bump testing can be done between calibrations to ensure proper response of your ozone sensor, and ensure that a sensor failure has not occured. We suggest bump testing your ozone monitor as often as daily in extremely critical applications. Weekly or montly internvals are common for bump testing your sensor between annual calibration periods.

A23-14 Ozone Calibration Kit for field calibration of ozone sensors
Ozone Puffer.

OG-3 Checker

The OG-3 Calibration Checker is primarily used for Eco-Sensors devices. This will create a known ozone level for bump testing or checking calibration of your sensor between calibration intervals.

OG-3 Ozone calibration checker for accurate bump testing ozone monitors
OG-3 Checker 

Ozone Chambers

We can also provide complete ozone chambers to be used for calibration purposes.  We build standard and custom ozone chambers for ozone exposure testing.  These chambers can also be used for calibrating one, or multiple ozone sensors at one time.  Using a calibration chamber any level of ozone desired can be chosen and entered into the control system, the chamber will maintain that ozone level, by placing your ozone sensors inside the chamber you can validate the readings of your ozone sensors and adjust accordingly.

CH-3 Ozone Mobile Chamber
CH-Series Ozone Chamber

 

Should you have any further questions on ozone monitor calibration please call our office.  We would be glad to help with your specific needs or to meet any specific criteria you have.

Materials ozone resistance chart

A common question when implementing ozone into a new application is how will ozone affect the materials we currently have in place.  Below is a useful chart showing the resistance of common materials to ozone oxidation. A = Excellent – no effect from ozone in normal operation B = Good – some oxidation from ozone, these materials can work with low ozone concentrations or short-term (less than 6-month) usage C = Fair – major effect from ozone oxidation, these materials should only be used for short-term applications or very low ozone levels D = Poor – severe oxidation from ozone will be noticed quickly.
ABS plastic B – Good
Acetal (Delrin®) C – Fair
Aluminum A – Excellent
Brass B – Good
Bronze B – Good
Buna N (Nitrile) D – Poor
Carbon Steel C – Fair
Cast iron C – Fair
Ceramic A – Excellent
ChemRaz (FFKM) B – Good
Copper A – Excellent
CPVC A – Excellent
EPDM B – Good
Fluorocarbon (FKM) A – Excellent
Hastelloy-C® A – Excellent
HDPE B – Good
Hypalon® A – Excellent
Hytrel® C – Fair
Kalrez A – Excellent
Kel-F® A – Excellent
LDPE C – Fair
Natural rubber D – Poor
Neoprene C – Fair
NORYL® B – Good
Nylon D – Poor
Polycarbonate A – Excellent
Polyetherether Ketone (PEEK) A – Excellent
Polyethylene B – Good
Polypropylene B – Good
Polyurethane A – Excellent
PTFE A – Excellent
PVC B – Good
PVDF (Kynar®) A – Excellent
Silicone A – Excellent
stainless steel – 304 B – Good
stainless steel – 316 A – Excellent
Titanium A – Excellent
Tygon® B – Good
Viton® A – Excellent
More useful information on ozone resistance can be found HERE We also perform ozone resistance testing in our ozone chambersContact us for information about this service should you have any materials you have specific questions on.

The Color of Ozone

Does ozone gas have a color? Yes, the color is blue. The problem is, ozone is normally found in gas, or in water at such low concentrations that the color is not visible.

Recently we performed some lab testing that required ozone levels in water greater than 100 ppm. The picture below provide some great examples of the color of ozone.

 

ozone color
0 ppm ozone on left vs >100 ppm ozone on right

 

Ozone in water
The Color of Ozone is visible in this image

 

ozone in water
An ATI Q45 Dissolved Ozone Monitor was used to measure dissolved ozone in water. The blue color of the water is even slightly visible in the flow cell used to measure ozone.

 

Dissolved Ozone in water
AS the dissolved ozone level increases the color of the water gets darker. The blue color in the water starts to become visually evident above 50 ppm.

 

Ozone levels in water turn water blue
The blue color of ozone is more visual in larger containers like this 1-gallon water jug.

 

Ozone Properties

The table below provides additional information on the properties of ozone. This shows the color of ozone is light blue, which is true. It is only visibly blue when ozone gas or ozone in water is at a very high concentration.

Property Ozone Oxygen
Molecular Formula O3 O2
Molecular Weight 48 g/mol 32 g/mol
Color Light blue Colorless
Smell Odor threshold of 0.001 ppm, pungent at high levels Odorless
Melting Point -192.5 deg C -218.79 deg C
Boiling point -111.9 deg C -1892.95 deg C
Critical Temperature -121 deg C -118.56 deg C
Critical Pressure 54.5 atm 5.043 atm
Density 2.144 g/l @ 0 deg C 1.429 g/l @ 0 deg C
Solubility @ 0 deg C 0.64 g/100 ml 0.049 g/100 ml
Electrochemical Potential 2.07 V 1.23 V

 

Ozone Solubility

Ozone is only partially soluble into water. The graph below shows the solubility of ozone into water based on water temperature and ozone gas concentration. As the water temperature decreases and ozone concentration increases ozone becomes more soluble into water.

Water pressure is the third and final factor in determining ozone solubility into water. However, as these images were taken of water at ambient pressure, this was not a factor used, and is not a required factor in achieving high ozone levels into water.

Do you have a need to achieve higher ozone levels into water? Or lab testing that requires dissolved ozone levels higher than off-the-shelf equipment can provide? Give us a call, we would be glad to help.

 

Comparison of oxygen concentrator styles

Oxygen Concentrator Types Compared

The purpose of this article is to explain the main types of oxygen generators available for ozone production and the advantages/disadvantages of each.

There are a few manufacturers of oxygen generators and a few differences between each. However, the fundamental operation of each manufactures version is very similar so that will not be reviewed here. We will focus on the three main styles of oxygen generators and how they could be implemented into your ozone generation system.

 

Sequal and OGSI OEM Oxygen Generator
Industrial oxygen generator

Generally smaller ozone systems will use the turnkey oxygen generators, and larger ozone systems with higher ozone production rates will use the industrial oxygen generators, while small to medium integrated ozone systems will use the OEM modules. However, there are applications where the industrial style oxygen generator is required for higher pressures, or turnkey oxygen generators are required due to the lack of space or available compressed air.

 

Turnkey Oxygen concentrators

Packaged oxygen generators that include an oil-less compressor, PSA oxygen generator, and all components to concentrate oxygen from ambient air. These units only need electrical power for operation and will provide oxygen at 93% purity.

 

Examples:

    • OGSI, OG-15 and OG-20
    • AirSep, AS-12 and Onyx
    • Sequal (Chart), Workhorse line

Turnkey packaged oxygen generators from airsep, OGSI, Sequal

 

 

Advantages:

  • Compact size allows for install in relatively tight spaces
  • Turnkey design allows for quick and easy operation
  • Relatively low cost

Disadvantages:

  • Lower oxygen output delivery pressures due to limitation of internal oil-less compressors
  • Poor reliability due to the lack of ability to purge moisture from process air
  • High maintenance costs due to poor reliability

 

 

OEM Modules

OEM models are offered by both OGSI and Sequal (Chart). The OEM modules use the same PSA sieve beds and valving systems as the turnkey packaged oxygen generators provided by those companies. These modules are commonly used to build ozone generators with integrated oxygen generators, or smaller integrated ozone systems.

 

Examples:

    • OGSI, OG-15-OEM and OG-20-OEM
    • Sequal (Chart), ATF Modules, ATF-8, ATF-12, ATF-15, ATF-23, ATF-25, and ATF-32

OEM oxygen generator from OGSI and Sequal

 

 

Advantages:

  • Compact size allows for install in relatively tight spaces
  • OEM configuration allows for installation into the same enclosure as an ozone generator if desired
  • Use of compressed air from plant air compressor may allow for very clean, dry air to be used increasing reliability dramatically when compared to the turnkey packaged oxygen generators.
  • Can provide slightly higher oxygen delivery pressure than turnkey packaged oxygen generators due to the higher compressed air inlet pressures that can be used
  • Lowest potential operational costs if plant compressed air is used

Disadvantages:

  • Installation equipment is required and must be done properly for reliable operation
  • Lower oxygen output delivery pressures than industrial oxygen generators
  • Potentially high replacement costs (applies to Sequal/Chart ATF-modules)

 

 

Industrial Oxygen concentrators

Industrial oxygen concentrators are used for medium to large scale ozone generation systems. These systems require compressed air for operation along with proper plumbing and set-up. Large steel cylinders are used to hold the molecular sieve material, and quality rebuildable solenoid valves are used to perform all purging and oxygen recovery actions.

 

Examples:

    • OGSI, OG-25, OG-50, OG-100, etc
    • AirSep, AS-A, AS-B, AS-D, AS-E, etc

Industrial oxygen generators from Airsetp and OGSI

 

 

Advantages:

  • Long term reliability of the system – only periodic maintenance is required
  • Lower overall long-term operational costs than other options due to low cost for rebuilding the unit
  • Higher oxygen delivery pressures (45 – 65 PSI)
  • Higher oxygen flow-rates available

Disadvantages:

  • Higher up-front capital costs for oxygen generator, tanks, and potentially the air compressor
  • May require more physical space for installation
  • Greater installation work required

View full page with additional Information HERE

Measure ozone production rates real-time

Tracking performance of an ozone system real-time is valuable for pilot test and even full-scale ozone systems and may be easier than you think.

Ozone system output is measured in g/hr or lb/day.  These values indicate the production rate of an ozone system.  Knowing the production rate of your ozone system real-time can have value in tracking system performance and preventing system failures by spotting potential issues before they start.

To calculate ozone production both the oxygen flow-rate and ozone concentration must be measured.  Both of these values can be measured real-time with digital devices installed inline with your ozone system.

ozone pilot system example install with measuring devices
Ozone generation system example with a Mass Flow Meter, UV Ozone Analyzer, and Oxygen Purity Meter installed inline.

Mass Flow Meter:

Mass Flom Meter GFM
GFM Mass Flow Meter

The GFM Mass Flow Meter will measure and display oxygen flow through your system real-time with a pressure compensated flow rate.  A mass flow meter measures the overall mass of gas passing through the device using ultrasonic technology.  This ensures reliable and repeatable flow measurements that do not require any conversions for temperature or pressure changes to the gas stream.  An LCD display or digital output can be provided to record oxygen flow rate.

UV Ozone Analyzer:

UV-HCR High Concentration Ozone Analyzer
UV-HCR Ozone Analzyer

The UV-HCR Ozone Analyzer will measure ozone concentration real-time to indicate the actual concentration of ozone produced by your ozone generator.   The UV Analyzer uses UV absorption technology to measure ozone concentration.  This unit provides an LCD display or digital output to record ozone concentration.

A sidestream of ozone gas must flow through the UV ozone analyzer (1-2 LPM).  Some of the ozone will be destroyed in the UV lamp measurement tube, the remaining must be converted back to oxygen safely using an ozone destruct device.

Oxygen Purity Meter:

OXM-12L Oxygen Purity Meter
OXL-12L Oxygen Purity Meter

The OXM-12L Oxygen Purity meter will measure oxygen purity real-time to ensure the oxygen purity remains stable and sufficient for efficient ozone production.  Ultrasonic technology is used to measure the composition of gas and ensure oxygen purity remains consistent.  This unit provides indicator lights to display oxygen purity and a digital output, an LCD display is optional.

Data Logger:

DL-3 Ecosensors data logger
DL-3 Data Logger

Data from each of the devices can be input into a PLC for real-time calculation and reporting of ozone production in g/hr or lb/day.  Data can also be recorded with a simple datalogger that can record data from each device real-time to be recorded for later review.

When measuring ozone concentration in % by weight the feed-gas (air or oxygen) must be factored into the calculation as oxygen and air have different weights. When calculating a percentage of a weight, it is necessary to know the weight of carrier gas.

 

Ozone Calculations:

Ozone Calculations and online calculators can be found at the links below:

 

Ozone generator output

((LPM x 60) x 0.001) x g/m3 = g/hr

Example = ((10 LPM x 60) x 0.001) x 10 g/m3 = 6 g/hr ozone production

 

Ozone Concentration in air by weight

100 g/m3 = 7.8% O3

1% = 12.8 g/m3 O3

1% = 7,284 ppm O3

Ozone Concentration in oxygen by volume

100 g/m3 = 6.99% O3

1% = 14.3 g/m3 O3

1% = 6,520 ppm O3


Ozone Generator Quality

We get many questions about the quality and price point of various ozone generators.  These are fair questions as there are many price points for an ozone generator with the same basic g/hr or mg/hr ratings.  Here we will try to lay out the biggest differences in ozone generators.

For a complete ozone generator buyers guide click HERE

The purposes of this article we will be looking only at corona discharge ozone generators producing ozone from dry air or oxygen.  We will not be evaluating UV ozone generators or ambient air ozone generators used for air treatment as these both have very limited application.

Corona Cell Materials

The heart of any ozone generator is the corona cell.  This is where the corona discharge occurs and produces the ozone.  Materials such as aluminum, tin (tin foil), low-grade stainless steel and plastics can be used to lower cost.  This is typically the case for Chinese made ozone generators.  These materials will be attached by the oxidation of ozone over time, and create leaks or a failed corona cell.

As these low-quality materials degrade they will contaminate the oxygen/ozone stream and allow impurities into the ozone stream.  Keep this in mind for water treatment or medical ozone applications.

higher quality ozone generators will use high-grade stainless steel (316L), quartz glass, ceramic, and pure Teflon.  These ozone resistant materials will withstand ozone and create a longer life to the ozone generator.

In 6-months of operation or very light use, there is no difference in corona cell materials.  Long term, after 6-months, or heavy use reliability of the ozone generator will be greatly affected. Costs will be higher to manufacture corona cells from higher quality materials.  However, the benefits are worth the cost.

Transformer

To produce ozone a high voltage spark is required.  This spark is occurring at all times and is an end-point ground.  A high voltage transformer is used to create these high voltages and sparks.  This transformer must be reliable and capable of handling the torment of shorting through a dielectric to ground at a high frequency for hours at a time.  We have found the best success with open coil resonant transformers, or oil cooled transformers.  Simple end-point transformers are less expensive and are commonly used in lower cost ozone generators, however, these will fail sooner.

Electronic Driver Boards

To produce ozone a high-frequency spark is used.  Electronic components must be used to create this high frequency.  Most commonly basic Mosfet transistors are used to switch DC voltage to create the high frequency.  Lower cost ozone generators will use one transistor to create the high frequency.  HIgher-end ozone generators will implement a series of transistors to split the workload.  

Circuit protection

In the event, the corona cell is contaminated, or adverse conditions exist the ozone generator driver board should turn OFF ozone production so that the transformer does not short directly to ground and fail.  Many lower cost ozone generators do not implement this circuit protection.  Those that do, may not react quick enough to protect the electronic equipment.  

Cooling fans

Ozone generators create heat.  That is a non-negotiable fact.  Many low-end ozone generators use small cooling fans that do not move sufficient air, and some use no cooling fan at all. 

Ozone Concentration

Ozone generators are normally rated with mg/hr or g/hr.  How efficiently this ozone is produced is a measurement of the ozone concentration, normally measured in % by weight, g/m3 or gamma.  It is important that the ozone generator you purchase produces the most g/hr at the highest possible ozone concentration.  Higher concentration ozone will consume less oxygen, dissolve into water more efficiently, and simply work better for every possible application.

 

These are a few of the most important components to review on an ozone generator.  Of course, low-quality ozone generators serve a purpose, they meet a low price point, and allow a user to determine if ozone is right for them.  However, do not be confused, a $100 ozone generator is not a lifetime investment.  And as with everything, higher quality is going to cost more.

Improve your livestock drinking water supply

As livestock producers in the USA grow in size, so do the water demands.  It is not always possible, and certainly not cost effective to bring municipal or rural water supplies to the farm, therefore drilling wells to supply water for on-site livestock is the best, and many times only option.  However, if your water supply is less than ideal, this causes potential issues.

We can help.  Ozone is used by many municipalities around the USA to treat drinking water.  As the technology improves we can now bring this same quality of water to your livestock operation cost effectively.  

Drinking Water Disinfection

Ozone and H2O2 can be used to disinfect drinking water on your farm.  Both well water and rural water can benefit from water disinfection.  By reducing bacteria in water cows will be healthier and water will taste better.  Drinkers will grow less bacteria, algae, and require less cleaning.  Livestock will drink more water when treated with ozone or H2O2.

How it works

Well Water

Well water commonly requires treatment to remove minerals or pathogens, even perfect well water may have no bacteria in it when pumped from the ground.  However, without any added disinfection this water can grow bacteria in it as soon as it is flowing through your pipeline and in your tanks.  This bacteria can spread illness, and make for generally unhealthy water in the drinkers.  Bacteria can easily be oxidized by ozone or H2O2, just as it is normally oxidized by chlorine in municipal water supplies.  However, using ozone or H2O2, dissolved oxygen levels in the water will increase and create healthier water without the added chloride contamination.

Common well water uses for ozone

Benefit of Ozone

Ozone can improve water quality to your livestock.  Animals will drink more water if it tastes better and looks better, cows that drink more water will eat more food, therefore, gain weight faster,  and are healthier animals overall.

Reducing bacteria in water will improve herd health and reduce maintenance on drinkers throughout your farm.

Using ozone as opposed to chlorine or H2O2 will save costs as there is no chemicals to purchase.  Ozone equipment is a one-time purchase with only minimal maintenance costs.

 

Ozone is dissolved into water using an ozone injection system.  The size of ozone system will be based upon your total water flow rate used.  Total water flow may be based on other applications for ozone on your farm or ranch.  See diagram of ozone injection system below for information on how ozone is dissolved into water.

ozone water for livestock production
Typical ozone injection system

1,4-Dioxane removal from water using ozone

1,4-dioxane
1,4-Dioxane molecule

 

The presence of 1,4-Dioxane in water sources has gained the attention of regulating bodies and the media recently.  Recent advances in analytical tools have given confirmation of the presence of 1,4-Dioxane in groundwater and drinking water sources, along with common sources or related contaminates.   This, along with the better understanding of the potential health effects of 1,4-Dioxane has created additional pressure at the removal of this VOC from drinking water and potentially contaminated groundwater sites.

 

Ozone may be the answer or a part of the answer to 1,4-Dioxane removal in water.  Our recent bench tests found complete elimination of 1,4-Dioxane in water within 10 minutes of treatment time.  Adding H2O2 to achieve the Advanced Oxidation Process (AOP) showed no benefit to ozone alone.

 

Test #1 used ozone gas at 6% by weight bubbled through a column of water
 
    Test #1 Test #1 Test #1
VOC 0 min 10 Minutes 20 Minutes 30 Minutes
1,1,1-Trichloroethane 66 ppb 4.5 ppb 0.31 ppb 0.28 ppb
1,1-Dichloroethane 380 ppb 50 ppb 9.6 ppb 0.93 ppb
1,1-Dichloroethene 140 ppb 0.34 ppb 0.34 ppb 0.34 ppb
1,4-Dioxane 120 ppb NR NR NR
Tetrachloroethene 140 ppb 0.12 ppb 0.12 ppb 0.12 ppb
Trichloroethene 410 ppb 0.22 ppb 0.22 ppb 0.22 ppb

Link to full results HERE

 

This data showed complete elimination of 1,4-Dioxane with ozone, along with reduction of all other VOC’s present in water at the same time.  

We have provided equipment for removal of VOC’s and specifically 1,4-Dioxane from drinking water and contaminated groundwater plumes.  Should you require specific equipment recommendations, we would be pleased to discuss this with you.  

 

Links to equipment we offer below:

 

For additional information on the removal of 1,4-Dioxane from water below is a list of technical papers and research we have compiled.

 

Technical Documents: