Techtextil 2024 - oxytec: Exhaust air treatment process in the textile industry

With exhaust air scrubber and UV/ozone technology to reduce VOCs, formaldehyde, H2S, odour and organic C

oxytec is the market leader in the field of air and water treatment based on photolysis oxidation, low-temperature plasma and scrubbers. We develop and sell systems for the purification and sterilisation of exhaust air, room air, surfaces and waste water in the catering, food, textile and waste disposal industries, in solvent-based processes, in the medical sector and for many other purposes worldwide.

In the textile industry, coating processes are used in the manufacture of technical textiles to provide fabrics or yarns with specific properties such as hydrophobicity. The coating agents can consist of organic products that are applied in aqueous or solvent-based form. This is followed by thermal treatment, during which all volatile components of the coating are released into the exhaust air (VOC, formaldehyde). In addition, the exhaust air also contains some of the fuels used in directly heated stenter frames, such as methane.

This exhaust air can be effectively treated with UV/ozone technology.

The environmentally friendly UV/ozone air purification process is based on the principle of photolysis oxidation. The exhaust air flows through special UV light-producing tubes (photozone lamps). Their radiation breaks down the organic molecular chains and converts natural oxygen (O2) into reactive oxygen (O3).Organic and odorous substances are oxidised. Photocatalytic degradation processes on the surface of the downstream catalyst effectively destroy the remaining odorous substances.All residues are completely biodegradable and are removed with the exhaust air flow. oxytec guarantees an odour reduction of 95 percent and an organic C and formaldehyde content in accordance with TA Luft.

Structure of the Clean Exhaust Air (CEA) systems

A CEA system always consists of the following components:Irradiation chamber with UV lamps (UV/ozone tubes)
Automatic CIP system
Control system
Reaction section up to the fan or downstream unit (e.g. catalyser)

A high penetration depth of the UV light must be achieved for optimum utilisation of the UV radiation output. This is achieved in an irradiation chamber with cross flow. The cross-section of the radiation chamber is determined by the exhaust air volume. The number of UV lamps depends on the air volume and the load of the exhaust air. The CIP cleaning system automatically keeps the UV lamps free of any deposits. It is operated automatically via the control system.

Further system components round off the photolysis oxidation/photooxidation process

To achieve even better results, the UV-C/ozone technology can be supplemented with additional system components:

Scrubber (W)

The oxytec exhaust air scrubbers effectively destroy water-soluble and odour-carrying particles in the exhaust air.The combination with a scrubber has proven to be particularly effective for exhaust air from laboratories, animal stables and smokehouses.It removes soluble components such as ammonia, reduces the exhaust air temperature before photolysis oxidation and enriches the exhaust air flow with moisture. In the textile industry, it cools the air and separates particles.Reaction section (R) after the UV/ozone chamberThe reaction section is dimensioned so that the substances to be degraded are oxidised for 3 seconds before they are released into the outside air via the fan or catalytic converter.

Catalyst (KAT) after the UV/ozone chamber

The activated carbon serves as a reaction surface for very long-chain molecules and for excess ozone in the event of load fluctuations. In wastewater treatment plants, the catalyser is used to separate the sulphur produced.

The advantages at a glance:

Compliance with official requirements (TA Luft, organic C, formaldehyde, odour requirements)
Low energy consumption (significantly lower investment costs compared to thermal post-combustion processes, significantly reduced maintenance and operating costs, on/off system)
Easy to retrofit (low construction costs, small space requirement, roof installation possible, simple installation)
Environmentally friendly (no use of chemicals, no waste water pollution, low CO2, all residues are 100% biodegradable)