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Exhaust air purification in the roasting plant (with heat recovery)

Typical emissions during roasting

 

Process stage Typical emissions Special features
Roasting process VOCs, coffee oils, roasting aromas, CO₂, smoke particles Very hot (up to 400°C), rich in fat and aromas
Emptying/cooling Roasting fumes, fine particles, moisture Impact load, diffuse degassing
Cleaning/de-stoning Dust, grease, thermal residues Stress from cleaning cycles, damp or sticky

Why is exhaust air purification important in roasting plants?

Roasting aromas and smoke are highly odorous, even in the smallest quantities.

Fine particles, tars, and oils settle in pipes, fans, and chimneys.

Without heat recovery, valuable energy is lost.

TA Luft and GIRL require emission reduction – even for smaller batch roasters.

Without exhaust air treatment, there is a risk of approval problems, complaints, or energy losses.

Legal requirements

  • TA Luft (2021): VOC and odor emission limits
  • GIRL (Odor Emission Guideline): for facilities in mixed-use or residential areas
  • BImSchG (if applicable): Approval requirement above a certain emission level
  • Requirements for occupational safety and hygienic air flow

Oxytec provides all evidence, measurement reports, and official documents for your planning.

Get advice now – for clean air and less energy loss during roasting

Would you like to eliminate odors, avoid residues, and recover energy?

Contact us—we will develop your customized solution for exhaust air purification in your roasting facility.

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Can be combined with air-to-air heat exchangers

Use of hot roasting exhaust air to heat fresh air or support heating

Lowers operating costs, reduces CO₂, improves overall efficiency

Particularly useful for continuous roasting systems or high batch turnover

Grease and oil separation to protect UV technology

Optional: metal filter, cyclone or droplet separator

For trouble-free, long-lasting operation with air containing grease and aromas

Typical areas of application

Coffee roasting – from small-scale production to large-scale facilities

Cocoa roasting, nut roasting, malt processing

Specialties such as spices, teas, grain extracts

Industrial roasting facilities, combined with packaging or storage

Your advantages with oxytec Clean Fryer Air

Odor reduction >90%, even with intense roasting aromas

Recover energy instead of letting it go to waste

No open flame – no gas, no soot, no CO₂ emissions

Less residue – less cleaning effort & fire risk

Compact, modular & retrofittable, even for small roasters

Approval-secure, economical & sustainable

FAQ – Frequently Asked Questions

What emissions typically occur during roasting?

Roasting produces:

  • Hot air with roasting vapors and CO₂
  • Odor-active VOCs (e.g., aldehydes, caffeic acids, aromatic substances)
  • Fine particles, oils, and tar substances from the bean or shell
  • Push emissions during emptying or cleaning

This mixture is particularly odorous, easily settles in pipes, and leads to complaints or energy losses if it is discharged unfiltered.

How does the Clean Fryer Air System work with frying vapors?

The system uses:

  • UV-C radiation to break down organic molecules
  • activated ozone, which oxidizes VOCs, smoke particles, and odors

Result: The exhaust air is cleaned without leaving any residue—no filter clogging, no combustion, no chemical additives.

How is heat recovery implemented technically?

Depending on the system design, Oxytec can equip the Clean Air System with:

  • air-to-air heat exchangers (for fresh air heating)
  • or air-water modules (for heating or process heat).
    This allows the hot roasting exhaust air to be used for energy purposes instead of being vented unused through the roof.

How much energy can be saved through heat recovery?

This depends on the roasting capacity and operating time – typical values are:

  • 20–40% energy savings in air heating
  • Recovery of up to 60–120 kW per system possible
  • Shorter payback period due to reduced gas or electricity consumption
  • Particularly effective for continuous roasting systems or high batch sequences.

How hygienic and low-maintenance is the system in continuous use?

Very easy to maintain:

  • UV lamps with a service life of approx. 8,000–10,000 hours
  • Prefilters protect against grease and residues
  • Pre-filters usually need cleaning every 4–6 weeks
  • Optional: automatic contamination monitoring
  • No burn-off, no filter replacement necessary – saving time and operating costs.

How effective is odor reduction in coffee or cocoa roasting?

The Clean Fryer Air was specially developed for intense flavors. In practice, we achieve:

  • > 90 % odor reduction, confirmed by
  • olfactometric measurement (according to DIN EN 13725)
  • VOC reduction according to TA Luft / VDI 3880

The effect is also reliable with complex roasting aromas, oils, and phenols.

Is the system eligible for approval?

Yes – Oxytec systems meet the requirements of:

  • TA Luft 2021 (VOCs, odors, organic emissions)
  • GIRL (Odor Emission Directive) for facilities in built-up areas
  • BImSchG / 31. BImSchV, if the facility is subject to approval

We provide the necessary technical evidence and emission reports and assist with communication with the authorities.

Can the system be integrated into existing roasting facilities?

Yes – the Clean Fryer Air System is:

  • compact and modular in design
  • retrofittable in existing exhaust air ducts or chimney pipes
  • also available as a container solution or external module

Integration is usually possible without major disruption to production.