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Ozone systems are often described with two numbers that sound similar but mean very different things: ozone concentration and ozone output. A specification may call for 10 percent ozone by weight, while the generator itself may be rated in grams per hour, kilograms per day, or pounds per day. Both numbers matter, but they answer different engineering questions.
Ozone concentration describes how much ozone is present in the oxygen-rich gas stream. Ozone output describes how much ozone mass the generator produces over time. Neither number is complete without knowing the gas flow associated with it.
This distinction becomes especially important when comparing generator ratings, designing an injection system, reviewing oxygen requirements, or deciding whether a system can meet a project ozone demand.
Ozone concentration tells you how strong the ozone-rich gas is. Ozone output tells you how much ozone mass is being produced. Gas flow connects the two.
At Pinnacle Ozone Solutions, generator performance is published with both output and concentration because a statement such as “1.6 kg/hr” is only meaningful when the concentration, feed-gas source, and operating basis are also understood.
Three Numbers That Should Never Be Separated
For a gas-phase ozone system, three values work together:
- Ozone concentration, commonly expressed as percent by weight or g/m3
- Feed-gas flow, commonly expressed as LPM, SLPM, SCFM, or another standardized gas-flow unit
- Ozone mass output, commonly expressed as g/hr, kg/day, or lb/day
If two of these values are known, the third can be calculated or checked. That makes them useful not only for design, but also for reviewing submittals and verifying analyzer readings during operation.
The engineering mistake is treating one of the values as though it describes the entire generator. A concentration percentage alone does not tell you generator capacity. A g/hr rating alone does not tell you how concentrated the gas is. Gas flow alone does not tell you how much ozone is being produced.
What Does 8% or 10% Ozone Actually Mean?
When ozone-generator specifications state 8 percent or 10 percent ozone, they are commonly referring to ozone concentration by weight in the gas stream. This is a gas-phase concentration, not the dissolved ozone concentration in the water.
Pinnacle publishes the following approximate conversion for ozone in oxygen:
1 wt% ozone in oxygen is approximately 14.3 g/m3. Therefore, 8 wt% is approximately 114.4 g/m3 and 10 wt% is approximately 143 g/m3.
That conversion immediately shows why gas flow matters. A cubic meter of gas at 10 wt% ozone carries more ozone mass than a cubic meter of gas at 8 wt% ozone. But the generator may not operate at the same gas flow, power level, or maximum mass output at both concentrations.
This is why concentration should not be interpreted as a direct measure of generator size.
g/hr Is the Capacity Number
For generator sizing, ozone output is fundamentally a mass-per-time value. Grams per hour and kilograms per hour tell the engineer how much ozone is available to meet the process demand.
Pinnacle publishes the basic output relationship as:
Ozone output (g/hr) = gas flow (LPM) x 60 x 0.001 x ozone concentration (g/m3)
The equation is simple, but it is one of the most useful checks in ozone engineering. It connects the analyzer concentration, the gas flow measurement, and the reported mass output.
If the concentration or gas flow changes, the calculated ozone mass output changes as well.
A Simple Calculation: Same Gas Flow, Different Concentration
Consider a simplified oxygen-fed example using 200 LPM of gas flow. This is a calculation example only, not a specific Pinnacle generator operating point.
At 8 wt% ozone, Pinnacle’s published conversion gives approximately 114.4 g/m3. At 200 LPM, the calculated ozone output is:
200 LPM x 60 x 0.001 x 114.4 g/m3 = 1,372.8 g/hr, or about 1.37 kg/hr
At the same 200 LPM gas flow but 10 wt% ozone, the concentration is approximately 143 g/m3:
200 LPM x 60 x 0.001 x 143 g/m3 = 1,716 g/hr, or about 1.72 kg/hr
With gas flow held constant, the higher ozone concentration carries more ozone mass. That is mathematically straightforward. Real generator operation, however, is more complex because the maximum achievable gas flow and ozone concentration are linked to the generator’s performance envelope.
A Real Pinnacle Example: The Peak
The published Peak ratings show why concentration and maximum output must be read together. On PSA oxygen, Pinnacle publishes up to 38.4 kg/day at 10 percent concentration and up to 45 kg/day at 8 percent concentration.
- 4 kg/day at 10% = 1.60 kg/hr
- 45 kg/day at 8% = 1.875 kg/hr
With gasified liquid oxygen, the same Peak platform is published at up to 45.6 kg/day at 10 percent and 54 kg/day at 8 percent, equal to approximately 1.90 kg/hr and 2.25 kg/hr respectively.
At first glance, some engineers expect the 10 percent rating to have the higher mass output because the gas is more concentrated. The published ratings show why that assumption can be wrong. Maximum ozone concentration and maximum ozone mass production are not the same operating point.
The correct question is not “Which percentage is bigger?” It is “How much ozone mass can the generator deliver at the required concentration and feed-gas condition?”
Why Higher Concentration Is Not Automatically Better
Higher gas-phase ozone concentration can be valuable because the same ozone mass can be carried in a lower total gas volume. Lower gas volume may influence injector sizing, gas-to-liquid ratio, piping velocity, contact-system behavior, and off-gas volume.
But higher concentration should not be selected in isolation. Engineers must consider the complete system, including:
- Required ozone mass for the process
- Generator performance at the selected concentration
- Available oxygen supply and feed-gas quality
- Injection and mass-transfer equipment
- Operating pressure and gas-flow range
- Cooling requirements
- Turndown and control strategy
- Off-gas handling and destruct capacity
A concentration setpoint that looks attractive on paper may not be the best overall operating point if it reduces usable capacity, limits turndown, or creates unnecessary constraints elsewhere in the process.
Concentration Also Changes the Gas Volume Required
The relationship can also be viewed in reverse. If the required ozone mass is fixed, increasing ozone concentration reduces the carrier-gas volume required to deliver that mass, assuming the comparison uses the same conversion basis.
For example, to carry 1,600 g/hr of ozone using the published oxygen conversion:
- At 10 wt% (about 143 g/m3), the theoretical gas flow is about 186 LPM
- At 8 wt% (about 114.4 g/m3), the theoretical gas flow is about 233 LPM
That difference matters because the ozone gas does not disappear after it leaves the generator. It must travel through piping, be drawn or forced into an injection system, mix with water, and ultimately be transferred or handled as off-gas.
For this reason, ozone concentration is not only a generator parameter. It is also a mass-transfer and hydraulic design parameter.
Do Not Confuse Gas-Phase wt% With Dissolved Ozone
Another common source of confusion is the use of percentages, ppm, and mg/L in different parts of an ozone system.
An ozone generator may discharge gas at 8 or 10 wt% ozone. The process water, however, may contain dissolved ozone measured in mg/L or ppm. These are completely different concentration bases and should not be directly compared.
The generator concentration describes the composition of the gas leaving the generator. Dissolved ozone describes ozone present in the liquid phase after gas-liquid transfer and ozone demand have affected the process.
A good submittal and control narrative should make the phase and unit basis clear every time a concentration value is used.
Why the Analyzer Matters
A modern ozone system may display several related values at the same time. Pinnacle’s current generator O&M documentation shows an operator interface displaying ozone concentration in percent by weight, concentration in g/m3, ozone production in g/hr, and gas-flow measurements.
That is useful because the operator can see both the concentration and the resulting mass production rather than relying on a single number.
If analyzer concentration changes while gas flow remains similar, mass output should change. If gas flow changes at a stable concentration, mass output should also change. Looking at the variables together helps operators identify whether a change is expected process behavior or a potential instrumentation, feed-gas, or equipment issue.
What Engineers Should Require in an Ozone Submittal
When comparing ozone generators, engineers should avoid specifications that list only a maximum lb/day or kg/day value with no concentration basis. At minimum, the review should identify:
- Guaranteed or published ozone output at the required concentration
- Whether the feed gas is PSA, VSA, VPSA, or gasified liquid oxygen
- Oxygen purity and feed-gas quality requirements
- Gas flow at the rated operating point
- Outlet pressure
- Power consumption and cooling requirements at the stated condition
- Available operating range and concentration-control strategy
- How ozone concentration and production are measured or calculated
The objective is to compare generators on the same basis. A higher published mass output at 8 percent should not be compared directly with another rating at 10 percent without understanding the concentration, feed gas, flow, and system consequences.
The Pinnacle Engineering Perspective
At Pinnacle Ozone Solutions, ozone-generator specifications publish output at defined ozone concentrations and feed-gas conditions because system design depends on all of these variables together.
The Peak, Summit, Zenith, and Apex platforms demonstrate the same basic engineering principle: maximum ozone mass output changes with the selected ozone concentration and oxygen source. The control system must then coordinate generator power, gas flow, concentration, cooling, and process demand within the available operating envelope.
For owners and engineers, the key is to define the treatment requirement first. How many grams per hour or kilograms per hour are required? At what gas concentration? With what oxygen source? At what pressure and operating range? Once those questions are answered, the generator and injection system can be evaluated on a common basis.
Conclusion
Ozone concentration and ozone output are related, but they are not interchangeable.
Percent by weight describes the ozone strength of the gas stream. Grams per hour describes ozone mass production. Gas flow connects the two and determines how much ozone mass is actually moving through the system.
Understanding that relationship helps engineers size generators correctly, compare equipment fairly, design injection systems, interpret analyzer data, and avoid one of the most common specification mistakes in ozone projects.
When reviewing an ozone system, never ask only “What concentration does it make?” or “How many pounds per day does it make?” Ask for both, and ask for the gas flow that connects them.
Technical Source Notes
- Pinnacle Ozone Solutions, Ozone Formulas and Conversions. Pinnacle identifies g/hr as a standard ozone-generator output measure and publishes gas-phase conversions for ozone in oxygen, including approximately 14.3 g/m3 per 1 wt% ozone.
- Pinnacle Ozone Solutions, Ozone Generator Output Calculators. The calculator relates oxygen feed-gas flow and ozone concentration to ozone mass output using the published g/m3 conversion basis.
- Pinnacle Ozone Solutions, The Peak technical specifications. Current published ratings identify separate maximum ozone outputs at 8% and 10% concentration for PSA oxygen and gasified liquid oxygen.
- Pinnacle Ozone Solutions, The Summit, Zenith, and Apex technical specifications. Published capacity tables similarly identify ozone output together with ozone concentration and feed-gas source.
- Pinnacle Ozone Solutions, Ozone Generator Operations & Maintenance Manual. The current operator-interface documentation displays ozone concentration in %wt and g/m3 together with ozone production in g/hr and gas-flow measurements.
