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Development of Novel Exhaust Air Decontamination Process and Equipment for Food Processing Industry’s Applications, based on Non-Thermal Plasma Discharge

Final Report Summary - EXAIRDEC (Development of Novel Exhaust Air Decontamination Process and Equipment for Food Processing Industry's Applications, based on Non-Thermal Plasma Discharge)

Effectively decontaminating exhaust air in the food production industry and enabling heat recovery

The European food preparation industry (FPI) is currently facing a high percentage of work related illnesses, increasing the amount of complaints about odour and contaminant emissions. Existing systems have low contaminant removal efficiency, creating a fire risk and high capital and operational costs due to lost energy (waste air is not applicable for heat exchangers).

Now, the EXAIRDEC process is increasing the contaminant removal efficiency by up to 98 % and is allowing the use of heat recovery. This process take place through a high-voltage, atmospheric pressure, ultra-short pulsed corona discharge (PCD).

'The EXAIRDEC project has developed an innovative process, which will significantly reduce fire and air contamination risk in the food processing industry. I'm excited to see the commercial success of this project in the future.' Prof. Brian McKenna, Past-President, European Federation of Food Science & Technology (Effost).

Major health problems are caused by low filtration efficiencies with current technology. Despite the progress made in contaminant removal in recent years, the food industry still faces a high percentage of work related illnesses (1.6 times the average). An estimated 8 % of all employees working in a food processing sector have had health complaints related to contamination and airborne diseases.

Odour emissions are becoming one of the most significant environmental issues, with complaints about odour becoming common as communities become more aware of air quality issues.

Also, contaminated extraction ducts pose a significant fire hazard. Even low concentrations of fat residue clog or form dense layers of fatty substances in the ductwork. This constitutes a dangerous combination with occasional sparks, flames and high air flow. A cost analysis of existing filter systems reveals that on average food processing companies have annual filter disposal and system maintenance costs of three to five per cent of its total added value.

Decontaminating the exhaust air

Efficient removal of cooking fumes, vapours and airborne particles would do much to reduce these high statistics. The EXAIRDEC project, secured with European Union (EU) Seventh Framework Programme (FP7) funding, is providing an innovative and highly effective removal of volatile organic compounds (VOCs) and soot particles from exhaust air and heat recovery.

Heart of the system

The EXAIRDEC system is innovative and technologically challenging. The EXAIRDEC system consists of an ultra-short (nanosecond) pulsed high voltage generator that drives the highly reliable PCD electrodes. Unlike the other systems, the EXAIRDEC system is capable of operating in high moisture environments.

EXAIRDEC project partners:

- Eesti Innovatsiooni Instituut (a Pera Technology company)
- National Physical Laboratory (NPL)
- Effost
- Kinema
- Labglass
- Setton
- Hitecsa (HiPlus).

Project context and objectives:

EXAIRDEC project is concerned with the development of an innovative contaminated air purification solution for food preparing industry's applications. It will effectively deconatminate the waste air emitted during the different food preparing processes that contains a variety of organic gaseous and aerosol contaminants, volatile organic compounds and particulate matter among others. This will result in the limitation of a number of problems currently present in the everyday practice of food preparing industry. Our research and development undertaken within this project will provide our SME-AG members as well as wider European community with the routes for overcoming the current existing technical barriers in the course of enabling the utilisation of latest auspicious scientific affordances and implementing the scientific achievements in practical situations.

Project results:

EXAIRDEC consortium developed and manufactured a pre-production prototype of a commercial kitchen exhaust air decontamination device that was capable of efficiently destructing most organic gaseous contaminants in an atmospheric pressure gas stream of flow rate of up to 700 m3 hr-1 at temperature range of 10 - 80 °C. Final tests were conducted in real kitchen environment at Nõmme Coffee shop in Tallinn, where air flow rate was slightly lower (505 m3 hr-1) and ethanol was found being the major VOC produced during the cooking process; resulted ethanol destruction efficiency of 98 %. EXAIRDEC two-stage prototype was coupled to a cyclonic particle separator (which located in the kitchen hood), and when the cyclonic separator and both PCD generators and electrodes were in operation, the particle number concentration was very low, around the range that would be expected in an ambient air at a rural site in the United Kingdom (UK). Consortium calculated that purchase of EXAIRDEC prototype would result capital cost of no more than EUR 5000 and operating cost level that results in an annual user cost of less than EUR 3000 for a 5 year depreciation time. The device uses no consumables; therefore the only operating cost is cost for the electricity. Consortium achieved the required decontamination performance with a space requirement for the supplementary system of less than 2 m3 with appropriate sound emissions. The sound from the HV-generator and from the electrodes was barely noticeable in the kitchen. Maximum power consumption of the prototype is approximately 2000 W (the power rate is adjustable from approx. 500 - 2000 W and depends on the generator output frequency).

Potential impact:

Widespread usage of EXAIRDEC device will have several positive impacts on environment. EXAIRDEC prototype coupled with high efficiency cyclonic filters will enable the use of heat exchangers in the exhaust and thus benefit from the usage of heat recovery. Heat recovery would provide increased energy efficiency usage.

EXAIRDEC device high VOCs decontamination efficiency will provide odour-free air exiting from the exhaust chimneys and provide therefore less contamination-caused complaints; better living and working conditions due to improved ambient air quality.

As EXAIRDEC device is not using any kind of consumables, therefore waste is not produced (e.g. filter cartridges).

Project website:
Relevant contact details: Mr Tiit Kerem, tel: +372 5045378