Ozone Equations: Concentration and Dosage
UNITS OF MEASURE
Abbreviations | For these formulas |
GPM | Gallons per Minute |
PPM | Parts per Million |
g/hr. | Grams per Hour |
SLPM | Standard Liters Per Minute |
% O3 | Percentage Ozone concentration |
g/m3 | Grams per Cubic Meter |
CFM | Cubic Feet per Minute |
PPHM | Parts per Hundred Million |
PHYSICAL PROPERTIES, STANDARD CONDITIONS: P = 101325 Pa, T = 273.3 K
Density of Ozone | 2.14 kg/m3 |
Molecular Weight of Ozone | 48 |
Density of Oxygen | 1.43 kg/m3 |
Molecular Weight of Oxygen | 32 |
Density of Air | 1.29 kg/m3 |
Density of Water: | 1000 kg/m3 |
USEFUL CONVERSION FACTORS (for water)
1000 liters = | 1 m3 | = 264 US gallons |
1 gal = | 3.785 liters | = 3785 ml |
1 m3 = | 35.3 ft3 | = 264 US gallons |
OZONE CONCENTRATION IN WATER
1 mg/l = | 1 ppm O3 | = 1 g O3/m3 water (by weight) |
OZONE CONCENTRATION IN AIR BY VOLUME
1 g O3/m3 = | 467 ppm O3 |
1 ppm O3 = | 2.14 mg O3/m3 |
100 pphm = | 1 ppm |
OZONE CONCENTRATION IN AIR BY WEIGHT
100 g O3/m3 = | 7.8% O3 (approximate) |
1% O3 = | 12.8 g O3/m3 (approximate) |
1% O3 = | 7284 ppm ozone |
OZONE CONCENTRATION IN OXYGEN BY WEIGHT
100 g O3/m3 = | 6.99% O3 (approximate) |
1% O3 = | 14.3 g O3/m3 (approximate) |
1% O3 = | 6520 ppm ozone |
ADJUST FLOW RATE CONVERSION
DETERMINING OZONE DOSAGE IN WATER: | |
Water Flow Rate x Ozone Dosage = | Required Ozone Production |
UNITS CONSISTENCY IS VERY IMPORTANT: |
Below is the formula for determining ozone generation requirements if you know the common water and ozone parameters (namely flow rate in gpm and ozone dosage in mg/l). |
Flow rate (gpm) x 3.75 l/gal x 60 min/hr. x ozone dosage (mg/l) = | ozone production (mg/hr.) |
Let's work through an example: |
How much ozone production is needed to dose 2 ppm into 20 gpm of water?(We will be using ppm throughout the rest of this example knowing that 1 mg/l = 1 ppm) |
20 gpm x 3.75 l/gal x 60 min/hr. x 2 ppm = 9084 mg/hr. ( gm/hr.) |
Remember that 9 mg/hr. will permit you to dose the water with 2 ppm of ozone. This does not mean that 2 ppm will be your final dissolved ozone concentration. Due to efficiency losses with injecting ozone and ozone demand of the water, your dissolved ozone concentration will be less. |
DETERMINE THE OUTPUT OF AN OZONE GENERATOR: |
Flow rate (lpm) x ozone concentration (g/m3) = ozone production (mg/hr.) |
Let's work through an example: |
The ozone concentration exiting an ozone generator is 120 g/m3 at 5 lpm of oxygen flow. What is the output? |
5 l/min x 120 g/m3 x (1 m3/1000 l) = 0.60 g/min |
g/min are not normal units in the ozone industry so we simply convert minutes to hours to get g/hr.: 0.60 g/min x 60 min/hr. = 36 g/hr. |
SAMPLE CONVERSIONS: |
Convert 140 g/m3 / 100 g/m3 x 6.99 wt. % = 9.8 wt. % |