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Exhaust air purification in food drying – neutralize odors & reduce energy losses

Typical emissions during food drying

Process example Typical emissions Special features
Drying of herbs Essential oils, terpenes, moisture Intense odor, high VOC content
Drying vegetables and mushrooms Organic odors, vapors, spores Warm, humid, often with slightly sticky particles
Meat and fish products Protein and fat components, ammonia, VOCs Strong odors, hygienically sensitive, high fat content
Animal feed (dry feed) Fatty acids, steam, protein vapors, VOCs Warm, fatty, strong odors

Why is exhaust air purification necessary in drying?

  • Odors from dryer exhaust air cause complaints and restrictions
  • High temperatures and humidity put strain on filters and ventilation systems
  • Without cleaning, valuable heat is lost
  • TA Luft, GIRL, and BImSchG prescribe emission reduction
  • Residues in exhaust air ducts can cause fire and hygiene problems

oxytec offers customized systems to solve these challenges technically and economically.

Legal requirements

  • TA Luft 2021 – VOC, odor, and particle limits
  • GIRL (Odor Emission Directive) – mandatory limits for residential development
  • BImSchG – Approval requirement for large drying plants
  • Food hygiene (HACCP) – no back transfer, no contamination
  • Energy efficiency regulations – useful for recovery

oxytec provides all documentation for approval, measurement planning, and subsidy applications.

Get advice now – for clean, efficient drying processes

Would you like to operate your drying plant in a low-emission, energy-efficient, and approval-compliant manner?

Contact us—we will plan your individual exhaust air solution.

hier anfragen

oxytec solutions for exhaust air purification in dryers

Clean Air System – UV ozone technology

Photochemically decomposes organic molecules and odorous substances – efficiently, without leaving any residue and without thermal combustion.

Advantages:

  • No gas consumption, no open flame
  • Compact & retrofittable
  • Highly effective against grease, protein, terpenes, VOCs
  • Odor reduction > 90 %

Heat recovery can be combined

Can be combined with heat exchangers on request to recover waste heat from the dryer exhaust air – for preheating fresh air or heating medium (e.g., for air, water, thermal oil).

Prefilter & droplet separator

Mechanical pre-stages for separating grease, vapor droplets, and particles –protection of UV technology and reduction of maintenance costs.

Typical areas of application

Vegetable & herb drying

Mushroom processing

Meat & fish snacks (e.g., dry sausage, protein bars, pet food)

Pet food industry (extrudates, dry food, treats)

Dryers in combination systems (e.g., roasting, seasoning, drying)

Your advantages with oxytec systems

Odor reduction >90% – verifiable & sustainable

Less energy loss through recovery

No thermal afterburning necessary

Low maintenance, food-safe, modular integration possible

Approval-secure & future-proof

FAQ – Frequently Asked Questions

Which emissions are particularly relevant in food drying?

Depending on the product, the following odors arise:

  • Organic odors (e.g., from herbs, mushrooms, meat)
  • Grease mist, protein vapors, VOCs
  • Water vapor carrying odorants
  • Aerosols & spore particles
    These substances are odorous, filter-burdening, and hygienically sensitive—they must be specifically removed from the exhaust air before they cause problems.

How does UV ozone exhaust air purification work with odorous substances and VOCs?

The system uses:

  • UV-C radiation to split organic molecules
  • activated ozone, which oxidizes odorous substances
    The process is residue-free, requires no thermal combustion, and is particularly suitable for humid, fatty exhaust air, such as that found in dryers.

Can UV ozone technology be used with warm, humid dryer exhaust air?

Yes – Oxytec systems are designed for air flows with high temperatures and humidity.

  • Max. continuous air temperature up to approx. 80°C
  • If necessary: heat exchanger or cooling upstream
    Oxidation works reliably even with high water vapor content – odors are effectively reduced.

How much heat is lost in the exhaust air—and can it be recovered?

Dryer exhaust air often contains heat losses of several hundred kW.
Oxytec can:

  • combine the Clean Air System with heat recovery
  • e.g., treat fresh air, heating water, or process heat
    This reduces your operating costs and CO₂ emissions—a compelling argument!

How complex is the maintenance of the system?

Maintenance is minimal:

  • UV lamps: Replacement approx. every 8,000–10,000 hours
  • Pre-filter cleaning: depending on the product, usually monthly
  • Optional: automatic contamination monitoring, remote maintenance, maintenance contract
    Compared to TNV or activated carbon: significantly less effort and risk of downtime.

What level of odor reduction can realistically be achieved with the Clean Air System?

Depending on the type of emission, we achieve:

  • > 90 % odor reduction
  • Confirmed by olfactometric measurement (EN 13725)
  • Reliable even with complex mixtures of substances such as fish, mushrooms, or proteins
    Optionally, the effect can be optimized with downstream activated carbon.

Is the system eligible for approval under TA Luft / GIRL?

Yes – Oxytec systems are:

  • compliant with TA Luft 2021 (VOC, organic substances)
  • effective against odors in accordance with GIRL
  • retrofittable for existing plants subject to the Federal Immission Control Act (BImSchG)
    We provide technical evidence, measurement reports, and support with the authorities.

Is its use in food-related areas hygienically safe?

Yes – the system is:

  • closed (no contact with the goods)
  • made of food-safe materials (e.g., stainless steel)
  • dry and residue-free during operation
    It meets the requirements of many HACCP and IFS concepts.