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Ultra-Violet Installation for Air Decontamination

#3449


Development of Impulse Ultra-Violet Installation to Decontaminate Air Flows from Biological Contaminants

Tech Area / Field

  • MED-DID/Diagnostics & Devices/Medicine
  • MED-OTH/Other/Medicine
  • CHE-RAD/Photo and Radiation Chemistry/Chemistry
  • PHY-PLS/Plasma Physics/Physics

Status
3 Approved without Funding

Registration date
02.02.2006

Leading Institute
Research Center of Toxicology and Hygienic Regulation of Biopreparations, Russia, Moscow reg., Serpukhov

Supporting institutes

  • MGTU (Moscow State Technical University) / Research Institute of Power Ingineering, Russia, Moscow

Project summary

Nowadays, studies and development of new highly effective technologies for air purification and disinfection is an urgent scientific and technical task. The actuality of this issue is confirmed by a number of factors, where the most important are increase of total level of environmental contamination, growing global tendency of immunodeficiency and dangerous infectious occurrence, high level of nosocomial infections as well as high risk of chemical and biological acts of terror.

Ventilation, filtration and ultraviolet (UV) bactericidal treatment are regarded as the basic components of the developing technologies for prevention of pathogenic contamination of air.

HEPA (High-Efficiency Particulate Air) filters are the highest efficiency air filters. They were developed in the 1940's by the USA Atomic Energy Commission for removing radioactive particulate contaminants from research areas. Today HEPA-filters are used for purification of radioactively contaminated products and asbestos particles. HEPA filter capture minimum 99.97% of contaminants 0.3 microns in size. However, НЕРА filters are not able to capture particles below 0.3 microns, which are the sizes of nanobacteria and viruses. In addition, the captured microorganisms and mold are growing, propagating, and penetrating through the fibrous filter layer to the air environment.

It is well known that UV radiation in spectral range of 200-300 nm has a pronounced photochemical and biocidal effect. In routine UV technologies, for bactericide air purification the mercury lamps (Hg-lamp) are used. However, these lamps have a disadvantage of radiating a narrow UV line of 254 nm and are characterized by low radiation rate. Biocide effect of mercury lamp is selective, since different microorganisms have different spectral characteristics. Low radiation rate of Hg-lamp requires a continued radiating. Besides, the presence of mercury inside the lamp makes it a potential gas bomb if it is destroyed in the ventilation system.

New biocide UV-technologies proposed in this project are based on the use of powerful flash lamps, where high-temperature xenon plasma (Xe-lamp) is a radiating substance. Xenon is a reactionless gas, therefore such kinds of lamps are ecologically friendly devices. A flash Xe-lamp emits a continuous spectrum from UV up to IR area with high intensity – several tens thousands times higher than a Hg lamp. These properties of Xe-lamps make new technologies very attractive and potentially perspective.

Some aspects of the use of UV technologies are still not clear. Flash plasma lamp is a rather complicated gas-discharge device. Its radiating characteristics depend on a great number of external factors, such as charge energy, operating voltage, charge capacity, chain inductance, overall lamp dimensions, xenon pressure, etc. Optimisation of operating regimes for the flash lamps intended for use in UV air purification is extremely important. At present, there are no engineering methods for designing flash plasma lamps, which meet the requirements to the modern technologies, or they are insufficiently developed.

However, for designing and development of UV-germicidal air purification, it is not enough to have only design models of plasma lamps. Such design-theoretical models should be accompanied by experimental data on angular and spectral distribution of lamp radiation energy at their different geometry and spatial arrangement; at that, specificity of interaction between highly intensive impulse UV radiation and biological contaminations must be taken into account.

The aspects mentioned above are of great importance for the further development of UV technologies for air purification and disinfection.

The objective of the project is investigation, development, and experimental approbation of basic concepts of new impulse UV technologies for disinfection of contaminated air flows and designing a prototype of impulse UV-germicidal module to be installed in the systems of ventilation and air conditioning.

At the SFES RCT&HRB of FMBA of RF, research within the project will be conducted by a team of scientists and experts who have a considerable experience in studies of biological aerosols including those of especially dangerous infections. For the studies, aerosol chamber installations and the equipment for aerobiological research will be used.

Scientists and experts of Division 4.3 of the SRIPE of Bauman MSTU carried out the research directed to the development of highly effective plasma impulse UV continuous-spectrum sources of radiation for 20 years. Based on the acquired intellectual and technical potential, the unique measuring devices and diagnostic installations have been developed. A number of the developed UV radiation sources and different-purpose devices designed on their basis have no analogues in the global practice.

In the planned studies the following results will be obtained:

  • experimental database on electrotechnical, energy and spectral-brightness characteristics of powerful flash plasma lamps for germicidal treatment of air in wide range of initial parameters changes will be created;
  • engineering methods for UV-plasma lamps parameters calculation will be developed and practical recommendations for selection of optimal operation mode parameters for germicidal air treatment will be prepared;
  • techniques for controlled aerosol contamination of air flows and methods for express-evaluation of UV-purification of air contaminated by representative microflora will be developed;
  • experimental data will be obtained in comparative study of continuous and impulse UV-radiation biocidal efficiency for different microorganisms;
  • power dosages of impulse UV-radiation for air disinfection effective against different microflora species will be determined;
  • engineering technique for calculation of UV-germicidal purification of contaminated air streams will be developed;
  • optimal operating practices for impulse UV-disinfection of air will be determined;
  • prototype of impulse UV-device for ventilation, air recirculation and conditioning systems will be designed and tested;
  • experimental and theoretical grounds and technical and economic assessment of the novel technology for air UV-germicidal treatment will be provided;
  • engineering recommendations on impulse UV-technology application for air disinfection in systems of ventilation, air recycling and air conditioning will be developed.

The project tasks will be fulfilled with the use of modern equipment and materials.

When developing theoretical models and engineering methods for flash lamps designing, on one part, we will use the obtained in the course of the project files of experimental data on energetic and spectral characteristics of lamps, and on the other – present-day physical knowledge on elemental processes going in impulse heavy-current discharges and optical and thermodynamic characteristics of electric-discharge (xenon) plasma. Design-theoretical models of impulse UV-germicidal air purification will consider spatial-temporal and spectral distribution of lamps radiation power, their geometry and positional relationship, as well as specificity of interaction between high-intensity impulse UV radiation and biological contaminants, which will be revealed in the experimental part of the project.

Experimental study of germicidal efficiency of impulse UV radiation will be conducted using modern aerosol chambers equipped with necessary complement instrumentation and provided with the developed techniques allowing conducting the studies under controlled conditions. For adjustment of technological modes of airflow contamination, aerosol generators of different designs will be used providing variation of aerosol particle size distribution and mass concentration. Aerosol chambers designs will be refined for conducting the project research.

The project findings will help considerably increase the efficiency of biologically-contaminated air purification, and assure high reliability and extended life of Xe-lamps in the systems of forced ventilation and conditioning in buildings and separate premises for therapeutic, pharmacological, food, technological etc. purposes. Based on the developed technology, the ecologically friendly portable devices able to neutralize any types of bacterial microflora could be designed.

The project corresponds to the ISTC tasks and purposes to involve highly qualified scientists formerly engaged in the development of powerful laser installations for military purposes and protection means against weapons of mass destruction in solving the urgent fundamental and national economic problems and to encourage integration of scientists into international scientific cooperation.


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