Ozone Destruct FAQ's

Information and frequently asked questions on ozone destruct devices.

Ozone gas is O3, or three oxygen (O) atoms combined to create one molecule. Ozone is useful for a wide variety of disinfection and oxidation application. However, ozone gas, at high levels can be toxic and hazardous to health in the gas phase. Therefore a method to eliminate ozone may be necessary in some applications. As ozone is simply another form of oxygen it can be safely broken down to diatomic Oxygen (O2). Below are common methods of ozone removal and answers to questions on ozone destruction.

 

QUESTION: How is ozone safely destroyed?

ANSWER:

Ozone is commonly removed using the following methods:

  • Carulite-200 based ozone destruct unit Carulite-200 is a hopcalite-type of catalyst using manganese dioxide and copper oxide. Carulite-200 is a true catalyst method of ozone destruction. 99.96% efficient at rated flow rates. Works well with dry ozone gas and humid gas such as off-gassed ozone from a water system. This is the most ozone destruction process used in ozone gas processes for high concentrations of ozone gas, either in dry processes or ozone off-gas from a water system. Carulite-200 is damaged by condensed water on the catalyst, VOC’s, acids and dust.

  • Carbon filter – Carbon reacts with ozone to form CO and CO2. In the gas phase, this reaction creates a high level of heat. Due the fact that carbon is a fuel source and air/oxygen is getting pushed through the carbon this is an extreme fire hazard. Use carbon with caution in gas phase reactions. Ozone dissolved in water can be safely removed with carbon filters but will consume the carbon filters quite rapidly.

  • UV-254 nm light – Ozone is destroyed at the 254 nm wavelength of UV light. (ozone is generated from UV light at 185 nm wavelength.)

    • In Air - The destruction of ozone efficiency in air is poor and similar to the efficiency of ozone generation from a UV light in air, a small percentage of the ozone will be reverted to oxygen in a UV light in the gas phase.

    • In Water – UV is very efficient at eliminating ozone in water. UV lights used for germicidal use using the 254 nm wavelength can be used to destroy ozone in water. To size the UV light properly, multiply standard flow-rate capacities for the UV light in water by 3x. This will achieve 90% reduction of ozone in water.

  • Thermal Oxidizer – Heat destroys ozone. Thermal oxidizers are used in wide variety of applications and industries to remove gas phase contaminates through combustion. The heat generated from a thermal oxidizer will also revert ozone to oxygen. This is typically not an efficient process from a capitol cost, or operating cost perspective. However, if a thermal oxidizer is already in place the ozone gas stream can be added to this for easy elimination of ozone gas.

  • Aluminium Oxide (Alumina) AL2O3 can revert ozone to oxygen with a near catalytic reaction. The reaction is not as efficient as with the carulite-200 material using Manganese dioxide/copper oxide, therefore limited commercial use of Aluminium Oxide has been implemented. It is important to be aware of this potential reaction when considering materials that can and will be used in ozone systems as some aluminum components could destroy ozone gas.

 

QUESTION: What is an ozone destruct unit?

ANSWER:

An ozone destruct unit is any device that is used to safely revert ozone (O3) gas back to oxygen (O2). This may be part of an ozone treatment process where ozone gas is used for air or water treatment, or this may be for lower levels of ozone to make a room safe for occupancy.

Ozone gas is unstable and will naturally decompose to oxygen on it’s own. However, in many applications, it is advantageous to revert ozone back to oxygen more quickly.

An ozone destruct unit may also be referred to as:

  • Ozone Scrubber

  • Ozone catalytic converter

  • Ozone catalyzer

  • Ozone Eliminator

  • And potentially other names that all refer to safely reverting ozone (O3) gas back to oxygen (O2)

 

QUESTION: Why do we want to destroy ozone?

ANSWER:

Ozone gas at low levels is naturally found in our environment and safe. However, at high levels, ozone gas is unsafe to breathe and will cause adverse health effects. Ozone is regulated by OSHA in the workplace. Ozone levels near personnel should be kept 0.1 ppm for 8-hour work days, 0.3 ppm for 15-minute exposure times, and 1 ppm for any instant exposure.

Ozone gas is also very corrosive and will cause material compatibility issues with materials in the area, or downstream process. When the ozone process is complete it may be wise to revert the remaining ozone gas to oxygen safely.

 

QUESTION: What type of gaseous Ozone Destruct Unit is right for my process?

ANSWER:

There are a variety of factors to consider when determining what device and what configuration you should use. Below are a few of the most common factors to consider.

  • Will a High Concentration Destruct Unit or Ambient Air Unit be required?

    • High concentration is commonly referred to “Process Gas” destruct unit

    • High concentration = 1 ppm ozone or greater

    • Ambient = Less than 1 ppm ozone

  • Will the gas stream be Wet or Dry? Wet gas streams require a heater band and a specific design inside the destruct unit to eliminate the potential of moisture condensation on the destruct media.

    • Wet = Any air stream with the potential of condensation

    • Dry = Process gas streams with dry-air or oxygen feed-gas directly from an ozone generator

 

QUESTION: What is a High concentration Ozone Destruct Unit?

ANSWER:

A high-concentration destruct unit will revert ozone (O3) gas back to oxygen (O2) in the gas phase at ozone concentrations above 20% by weight. These units will use Carulite-200 catalyst media in a stainless steel shell. Proper design will consider air-speed velocity past the catalyst material. When designed properly an ozone destruction efficiency of 99.96% will be achieved.

Oxidation Technologies builds the CDU-Series ozone destruct units to work with high-concentration applications. Take note of the Wet or Dry gas flow info below to determine what options may be necessary and how to size the unit properly.

 

QUESTION: What is an Ambient Air Ozone Destruct Unit?

ANSWER:

An ambient air ozone destruct unit is designed for operation in rooms, enclosures, or any space where ozone gas in the ambient air is unsafe and must be eliminated. These units will have fans built-in to flow air through the device and will be rated by the air-flow created by these fans. Ozone destruction efficiency of 90% is typical with ambient air destruct units. Meaning, 90% of the ozone gas passing through the unit is destroyed.

Oxidation Technologies builds the CDA-Series Ozone destruct units to be used with Ambient Air

 

QUESTION: What is a Dry Gas Ozone Destruct Unit?

ANSWER:

High-concentration ozone destruct units will be rated differently for wet or dry gasses. The design air speed velocity is different and the destruction efficiency will be altered. The dry-gas ratings of the high concentration ozone destruct units is based on air or oxygen gas stream with ozone that has a dew-point of -40 deg F or lower. This is typically the process gas stream directly from an ozone generator, not an ambient air gas stream.

If the gas stream will have a higher humidity level than -40 deg F the ozone destruct unit should be sized accordingly with a lower overall air flow-rate than rated.

Oxidation Technologies builds the CDU-Series ozone destruct units to work with dry gas applications. Use the higher gas flow ratings listed for each. The heater option is NOT required with dry gas streams.

 

QUESTION: What is a Wet Gas Ozone Destruct Unit?

ANSWER:

High-concentration ozone destruct units will be rated differently for wet or dry gasses. The design air speed velocity is different and the destruction efficiency will be altered. The wet-gas ratings of the high-concentration ozone destruct units is based on air or oxygen gas stream with potentially condensing levels of humidity. This can be any gas stream with humidity in it, but is most commonly an ozone off-gas stream from an ozone water system process where ozone gas was introduced into water and the remaining off-gas that did not dissolve is passed through an ozone destruct unit.

A heater is used on the ozone destruct unit in these cases to maintain warm temperatures of the catalyst material and prevent condensation. An air gap is designed into the ozone destruct unit to allow the process gas to increase in temperature, and if there is any actual water droplets they can drop out in that gap prior to contacting the ozone destruct catalyst material.

Oxidation Technologies builds the CDU-Series ozone destruct units to work with wet gas applications. Use the lower gas flow ratings listed for each. The heater option is required with wet gas streams. This will include an air gap at the destruct unit inlet along with a heater band to properly warm the air prior to contacting the catalyst media.

 

QUESTION: What happens to the ozone gas within the destruct unit?

ANSWER:

This will vary depending upon style.

  • High Concentration Ozone Destruct Units using Carulite-200 Catalyst Media will revert Ozone gas (O3) to Oxygen (O2) through a true catalytic process. This is a true catalytic reaction requiring no consumables. This is an exothermic reaction, the destruct unit will have a temperature increase as ozone is catalyzed.

  • Carbon based destruct units used with air or water will react O3 to CO and CO2 and over time deplete the carbon material.

  • UV light will disassociate the Ozone (O3) molecule to create Oxygen (O2), however within this reaction in the presence of water or water vapor the reaction may create Hydroxyl Radical (-OH). UV is commonly used to create high amounts of Hydroxyl Radical which is referred to as an Advanced Oxidation Process (AOP).

 

QUESTION: What is the catalyst material used in the CDU-Series Destruct Units?

ANSWER:

Carulite-200 is used as the destruct media in all CDU-Series and High Concentration Ozone Destruct Units. Carulite-200 is a hopcalite-type of catalyst using manganese dioxide and copper oxide. Carulite-200 is a true catalyst method of ozone destruction. 99.96% efficient at rated flow-rates. Works well with dry ozone gas and humid gas such as off-gassed ozone from a water system. This is the most ozone destruction process used in ozone gas processes for high concentrations of ozone gas, either in dry proceses or ozone off-gas from a water system. Carulite-200 is damaged by condensed water on the catalyst, VOC’s, acids and dust.

 

QUESTION: Can I get an SDS (MSDS) for Carulite-200?

ANSWER:

Yes link here – Caulite-200 Safety Data Sheet

 

QUESTION: How long will Carulite-200 last? Does it require replacement?

ANSWER:

While the Carulite-200 material is a true catalyst is still requires periodic replacement. We suggest annual replacement. The material will break-down over time and “dust” leaving air-gaps and voids in the destruct system. Also, the material may become poisoned by VOC’s, coated with dust, nitric acid or other airborne contamination. For safety reasons, replace annually.

 

QUESTION: I have a high-concentration Ozone Destruct Unit, can I buy replacement Catalyst?

ANSWER:

Yes we sell Carulite-200 in 1 lb increments and offer quantity discounts. Link here – Carulite-200 for sale

 

QUESTION: Can I build an ozone destruct device from PVC or another plastic to save costs?

ANSWER:

NO. The catalytic reaction with ozone and Carulite-200 is exothermic, meaning heat is generated. The heat can rise high enough to melt and potentially burn PVC materials. PVC is flammable and you are flowing air/oxygen through this device to continue to feed this flame with an oxygen source. NEVER use any potentially flamable material to house Carulite-200.

QUESTION: I have a high-concentration destruct unit, the material inside looks like carbon, can I replace it with carbon?

ANSWER:

NO. Carbon is flammable. This will eventually create a fire inside the destruct unit that may create hazards at the discharge of the exit. Never use carbon to destroy ozone in the gas phase at levels above 1 ppm.

 

QUESTION: My Carulite-200 Catalyst got wet, do I need to replace it?

ANSWER:

Replacement is easiest. However, it is also possible to remove the catalyst from the ozone destruct unit, place in an oven and bake at 500-deg F for a few hours (until dry). This will remove the moisture, and typically eliminates most VOC’s and dust contamination from the catalyst allowing it to be re-used.

 

QUESTION: Is Carulite-200 safe to handle?

ANSWER:

Carulite-200 is not a hazardous substance and is perfectly safe. However, there is a fair amount of dust associated with handling it, therefore proper protective equipment for any dusty environment should be used.

 

How do I dispose of Carulite-200?

ANSWER:

Carulite-200 is not a hazardous waste substance and can be disposed of in landfills. However, if the Carulite has been poisoned with toxic or hazardous materials, proper disposal criteria of those materials should be followed.

 

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