Thermal Recuperative Oxidizers have been used for many years as a straightforward and effective means of destroying organic fumes in process exhaust gas. Thermal Oxidizing Systems can be applied to a wide variety of processes. Thermal Oxidizing Systems are often the technology of choice because of durability and adaptability over a wide range of operating conditions.

• Proven technology for oxidation Oxidation
  Thermox™ thermal oxidizers efficiently reacts Hydrocarbons (HCs) and Volatile Organic Compounds (VOCs) with oxygen in the air to form naturally occurring carbon dioxide and water vapor (HC+O2+ HEAT H20 + CO2 +HEAT). This reaction occurs when the air is heated to a sufficiently high temperature, typically 1400-1600ºF (760-870ºC).of volatile organic compounds (VOCs) and for the control of odorous emissions with greater than 99% efficiency!
• Recognized as the Best Available Control Technology (BACT) and Maximum Control Technology (MACT) for many industrial process Industrial Process
  Asphalt Processing
  Chemical Processing
  Coating and Laminating
  Composites
  Food Processing
  Metalworking
  Pharmaceuticals
  Pill coaters
  Ethelene Oxide sterilizers
  Printing and Converting
  Soil Remediation (soil vapor extraction)
  Water Remediation (VOC stripers)
  Specialty Applications - O₂ removal from Nitrogen streams
  Textiles
  Wood Products
  Mine Exhaust (CO removal)
  Ethanol Production (Dryers)
  
• Thermox™ RecuperativeRecuperative – meaning to recover and restore Thermal Oxidizers reduce energy costs by using a pre-heater ( heat exchanger ) to recover the heat from the post oxidized air to preheat the incoming process air. Further savings can be gained with a secondary heat recovery

  Secondary Heat Recovery
  Proven technology for oxidation of volatile organics compounds (VOCs) and for the control of odorous emissions to greater than 99% efficient!

  Secondary Heat Recovery (SHR)
  In some cases the waste heat from the hot combustion exhaust (which normally is vented to the stack),are recovered in a secondary heat recovery system resulting in additional energy savings. Contact Air-Clear Engineers to analyze your project for secondary heat recovery feasibility.

  • The following are examples of the how the waste heat can be utilized for process or plant use:
  • Reheated air - return to process or as building heat
  • Waste heat boiler - to produce process steam or hot water
  • Hot oil heater - to produce hot oil for use in the process
   or ‘economiser”
  Recuperative –meaning to recover and restore
• The Thermox ™ Thermal Oxidizer is designed to provide reliable stable operation over a wide range of process conditions Process Conditions
  Process conditions such as the process volume, temperature VOC loading, all directly affect the performance of a Thermal oxidizer. A properly designed system will have the burner and volumetric turn down, response time controlled by a PLC to respond to changes in these process conditions.
• Small or large flows as well as multiple sources feeding one thermal Oxidizer can utilize thermal oxidation to control emissions. The Thermox ™ is also an excellent choice for intermittent ON-OFF use.
• Thermal oxidizers can rapidly adjust to changes in VOC loadings. When equipped with a
  High Temperature Bypass Valve (HTBV)

  High Temperature Bypass Valve (HTBV)
  The pollutants often referred to as VOC’s (Volatile Organic Compounds); provide a heat release as they are oxidized or combusted. The higher the VOC concentration, the more heat is released, reducing the amount of supplemental fuel required to maintain the oxidization temperature. In combination, the heat recovery and VOC's heat output can often provide sufficient heat to reach the oxidation temperature without any burner heat input. In fact, at times the VOC loading can provide more heat than is needed to maintain the oxidation temperature. This excess heat can cause damage to the preheater and / or unscheduled oxidizer shutdowns and in extreme cases can cause damage to the oxidizer. To prevent these concerns, a Hot Bypass is used to direct the clean oxidizer exhaust around the primary heat exchanger. This redirection of hot air creates an unbalanced flow in the heat recovery system (more dirty cold air than clean hot air). The result is a lowering of the preheat temperature and a return to stable operating conditions.

  The Thermox™ Recuperative Thermal Oxidizer uses a specialty high temperature (1400°F-1600°F) damper with modulating control. Despite constant exposure to high temperatures, these high temperature valves have minimal leakage even after years of use.

• Flexibility - Custom design-meets your specific project Project
  Air-Clear personnel listen to our customers so they understand their priorities. What are the environmental requirements, capital cost vs. operating cost; on line reliability, project schedule, future expansion ETC. So that in the end, every dollar spent is optimized, invested in the areas most critical to our customers’ operation.  objectives at the lowest cost possible

Best Value
Air-Clear relies on a network of world class providers of specialty components selected by our Engineers for integration into cohesive system. Suppliers are selected based on the design features, quality of construction, and cost competiveness. In addition Air-Clear Fabricates internally, eliminating the cost mark ups passed on by subcontracted fabricators.

Post commissioning support
Worldwide Capability- AC has completed projects worldwide. Air-Clear supports these projects on an ongoing basis by a combination of in house resourcesResources
Field support is provided throughout the world on all of Air-Clear Systems. Air-Clear has full-time field technicians and engineers ready to support all of Air-Clear's equipment. Additionally, Air-Clear often provides in-depth training to local mechanical / electrical contractors who can support Air-Clear's field technicians. Field support can be extended indefinitely by means of maintenance / service contracts. Remote support for our customer's personnel is only a phone call away. Air-Clear Engineers can dial up equipment through modems integrated in our controls to provide real time monitoring and diagnostic services., remote diagnostics and localized support personnel.

• FATFAT
  All Air-Clear Systems are designed, manufactured, assembled and tested prior to shipment to ensure trouble-free installation and start-up: Major components, such as burner systems, fans, VFD, flow control valves,  instrumentation and control programming for process and safety interlocks, are tested at Air  Clear's facilities prior to installation at our customer's site.
  
  When practical, the equipment is totally assembled for verification of fit of components. Shop assembly and testing allow Air-Clear Engineers to verify performance prior to shipment.  Any non-conformity is corrected before installation at the customer's site.
  Benefits to the customer are:
  
  
  • Faster, trouble free installation reduces installation costs
  • Less downtime, increased revenue from production
  • Higher on-line reliability from day number one
  Our customers are encouraged to witness the shop testing. This is often an excellent opportunity for our customers to receive training on the equipment this allows for the customer's personnel to become  comfortable and knowledgeable with the equipment before it is even shipped! - Factory Acceptance Test – reduces commissioning and start up time by running a thorough diagnostic system check PRIOR to shipment
• Air-Clear has extensive knowledge of various materials of construction and metallurgies to insure long-term system performance and reliability, especially when working on ChlorinatedChlorinated
  When chlorinated compounds are oxidized one of the resulting by products is Hydrochloric Acid (HCL).This HCL must be neutralized or scrubbed and requires auxiliary equipment in the form of a quench to lower the temperature and a Caustic scrubber to absorb the HCL before being released to atmosphere. The HCL also presents a potential metal corrosion problem for the Carbon Steel. To combat this AC often fabricates all or part of the RTO using corrosion resistant materials. Protective coatings are used beneath the insulating modules to offer addition protection to the steel . applications

Pilot testing, rental
Lease options and pre-owned- ‘re-commissioned’Re-Commissioned
Air-Clear has small trailer mounted units available for rental or sale. These systems are often used for remediation sites or for pilot testing and performance verification. equipment are available from Air-Clear

How Air-Clear Thermox™ Recuperative Thermal Oxidizers Works

• Prior to ignition, the air inside the oxidizer must be purged to extract any residual gas that may have leaked into the chamber. The purge is controlled with a timer; this insures the proper volume of fresh air. The blower, in conjunction with an ambient air valve, forces clean air through the system. To prevent the possibility of drawing additional contaminated air from the process, an isolation valve closes off the process and permits ambient (fresh) air to enter the system.
• Requirements for MACTMaximum Achievable Control Technology (MACT), BACTBest Available Control Technology (BACT), LAERLowest Achievable Emission Rate (LAER)  and RACTReasonably Available Control Technology (RACT) making it the preferred oxidation technology for many applications.
• Upon completion of the system's purge, the gas blocking valve opens and the burner pilot is ignited, and the main gas blocking valves open allowing the oxidizer to reach the operating temperature.
• Contaminated process air is forced (pushed) into the thermal oxidizer by means of a centrifugal blowerBlower
  Air-Clear Engineers utilize leading blower manufacturers assuring optimum fan performance for the appropriate process. Air-Clear Engineers select fans so that they perform at approximately 90% of total capacity. This provides the customer with a quieter fan and extended fan life . A backward inclined industrial grade centrifugal fan is the fan of choice for most Thermox™ Recuperative Oxidizer Systems, because of their efficiency and ability to perform over a wide operating range.
  
  Note: Changes in the airflow rates that may result from process changes, such as turning on or off multiple emission sources, are controlled by use of a damper or VFD (Variable Frequency Drive).  or in some cases, as a result of a positive process pressure.
• As the contaminated process air moves into the heat exchanger

  Heat Exchanger
  Thermox™ Recuperative Oxidizer Heat Exchanger, used to recover heat from the hot oxidizer exhaust to heat incoming process air, is called a "Pre-heater" or primary heat recovery (PHR).

  AC uses two types of pre-heaters:

  • Shell and tube
  • Plate and frame

  Shell & Tube Heat Exchangers
  In general, shell and tube exchangers are more durable units capable of tolerating more aggressive process conditions. They are also easier to clean and repair. Therefore, shell and tubes are most often used in high temperature and dirty or corrosive applications.

  The materials of construction vary from 304 Stainless Steel, Hastelloy or other more exotic materials. The tubes and tube sheet thickness also vary to meet the specific project requirements.

  In addition to our unique and flexible design, Air-Clear Tubular heat Exchangers include these features:

  • Internal insulation to create a cold flange connection for minimum shell expansion
  • Expansion joints designed for the frequent thermal cycling of a recuperative oxidizer. Laser cut tube sheets reduces stress at weld points
  • Tubes are rolled and welded to the tubesheet
  • A leakage test is performed in the Air-Clear Shops before shipment.
   (pre-heater), the process gas is heated by means of the hot exhaust gas exiting from of the combustion chamber.
• The preheated air then enters the combustion zone. The air temperature must be raised to the required oxidation temperature, usually between 1,400-1,600 ºF. The additional heat that is required to reach the oxidation temperature is provided by a burnerBurner
  Air-Clear utilizes burner designs from the leading burner manufactures based on specific requirements such as turndown, NOx output,preheat temperatures etc. using supplemental fuel such as natural gas, propane, oil or liquid organic wastes. Preheating of the contaminated air in the pre-heater heat exchanger can greatly reduce the amount of supplemental fuel required.
• The combustion chamber (reactor) is sized to provide the required residence time, which will allow for the desired conversion efficiency. The reactor is internally insulated with high temperature
  ceramic fiber  Ceramic Fiber
  
  Unlike some of Air-Clear competitors who use blanket and pin, Air Clear uses ceramic fiber modules. While these modules are initially more costly, the energy saved and the long life expectancy with virtually no maintenance makes modular insulation the best overall value. A stainless steel frame supports each module; the frames are individually welded to the inside of the combustion chamber. When the adjacent module is put into place, it generates lateral support by compression. Air-Clear modules are made from high purity ceramic fibers. The modules are constructed to prevent spalling or erosion of the fibers which would normally result when the fibers expand in different directions when heated. Efficient, durable and low maintenance make the Air-Clear insulating system a key part of the Thermox™ Recuperative Thermal Oxidizer System.
  
  In corrosive environments where acid gases create the potential for attack on the oxidizer walls, the modular construction studs provide a unique solution. With the module in place the wall temperature is approximately 150°F, well below the maximum temperature of corrosive resistant mastics. This allows Air-Clear to coat the interior surfaces prior to insulating the unit, protecting the metals from acid condensates and corrosion.
  
  In some applications Air-Clear uses high-density ceramic fiber sleeves to insulate the combustion chamber. These sleeves are particularly useful when lining smaller reactors with diameters under 3'. Larger diameters make modular insulation a bit more difficult. Two or more sleeves are interlocked by means of a male/female connection. The round fiber sleeves are strong and chemically resistant. They can be brought rapidly up to temperature without concern for cracking or spalling. This proprietary sleeve method of insulating is often used in the Air Clear Chameleon System. These trailer-mounted units are designed for site-to-site mobility.
  module to conserve heat. In general AC Systems have exterior temperatures which average less than 150°F
• The oxidation reaction breaks down the Hydrogen / Carbon bonds using heat energy. In the presence of oxygen, the result is reformed products, namely Carbon Dioxide (CO2) and water vapor (H2O) a typical reaction using toluene as (C7 H8 + 9O2 + Heat -> 7CO2 + 4H2O+ exotherm).
•  The post-oxidized air passes on the opposite (clean) side of the preheat heat exchanger. The clean and dirty sides of the exchanger passages are completely isolated, preventing mixing or cross contamination of the incoming and outgoing air streams.
• The hot, post-oxidation gas flows in an opposite direction to the incoming air. As the two streams pass each other, heat from the post-oxidized "clean" air is transferred to the cooler incoming process air.
• As the "clean" air exits the heat exchanger, it passes through the exhaust stack before being released to atmosphere.
•  In some cases, there is a need to recover the remaining waste heat energy for process, building heat or steam. In these cases, a secondary heat exchanger, often referred to as an economizer, is used to recover even more of the heat from the oxidized exhaust. In its simplest form, a pair of dampers works together to direct all or some of the hot exhaust from the stack to the secondary heat exchanger

  Secondary Heat Recovery (SHR)
  In cases where the waste heat from the hot combustion exhaust (which normally is vented to stack), a secondary heat recovery system can be installed.

  The following are examples of the how the waste heat can be utilized for process or plant use:

  • Reheated air - return to process or as building heat
  • Waste heat boiler - to produce process steam or hot water
  • Hot oil heater - to produce hot oil for use in the process

  Contact Air-Clear Engineers to analyze your project for secondary heat recovery feasibility

  . Clean ambient air flows across the other side of the exchanger, heating the clean air for process or building heat. The two streams are isolated, eliminated any potential mixing or cross contamination.
• In combination, the pre-heater and VOC's heat output can often provide more heat than is needed to maintain the oxidation temperature. In these cases, a High Temperature Bypass Valve (HTBV)

  High Temperature Bypass Valve (HTBV) In some cases, a Hot Bypass is used to direct the clean (hot) oxidizer exhaust around the primary heat exchanger to avoid damage to the exchanger.

  The pollutants often referred to as VOC’s (Volatile Organic Compounds); provide a heat release as they are oxidized or combusted. The higher the VOC concentration, the more heat is released, reducing the amount of supplemental fuel required to maintain the oxidization temperature. In combination, the heat recovery and VOC's heat output can often provide sufficient heat to reach the oxidation temperature without any burner heat input. In fact, at times the VOC loading can provide more heat than is needed to maintain the oxidation temperature. This excess heat can cause damage to the preheater and / or unscheduled oxidizer shutdowns and in extreme cases can cause damage to the oxidizer. To prevent these concerns, a Hot Bypass is used to direct the clean oxidizer exhaust around the primary heat exchanger. This redirection of hot air creates an unbalanced flow in the heat recovery system (more dirty cold air than clean hot air). The result is a lowering of the preheat temperature and a return to stable operating conditions.

  The Thermox™ Recuperative Thermal Oxidizer uses a specialty high temperature (1400°F-1600°F) damper with modulating control. Despite constant exposure to high temperatures, these high temperature valves have minimal leakage even after years of use.

   is used to direct the clean, hot oxidizer air around the heat exchanger, rather than allowing it to go through the pre-heater.

System Controls
The "brains" of the Air-Clear Thermal Oxidizers are the instrumentation and controls. PLC's -
Program Logic Controllers