аэродинамика воздухоочистных устройств с зернистым слоем

314 Summary
The basic advantage of these catalysts is low aerodynamic resistance, resistance to
erosion and the possibility of cleaning gas polluted with suspended particles. As
practice shows, granulated catalysts can be employed for gas treatment when the
concentration of suspended particles inside does not exceed 2 mg/m 3 (Darlington
et al. 2001; Gelhomenie et al. 2001, 2002; Deshusses, Cox 1999; Deshusses, Johnson
1999, 2000; Devinny et al. 1999; Dhamwichukorn et al. 2001; Elmrini et al.
2004; Engesser, Plaggemeier 2000; Estimated ... 2006).
The main function of charging a bio-filter is to create a large surface for pollutant
adsorption. Charging is also used as a source of nutrients for microorganism
population. In some charges, the required nutrients are not enough, and therefore,
in order to ensure high activity of microorganisms, they need to be watered with
water-saturated biogenic elements (mineral salts). Peat, soil, compost and mixtures
thereof are for the most part used to biologically clean the air from organic and
inorganic chemical pollutants. Wood sawdust, bark and various types of crushed
waste have also received wide application globally. Moreover, the charges of the
artificial origin such as polyvinyl chloride balls, star-shaped polymers, polypropylene
cylinders, balls filled with carbon or ceramics, granulated glass, ceramic cubes
are used to reduce the aerodynamic resistance of bio-filters. An inorganic charge of
natural origin and natural zeolite can also be applied for biological air treatment.
The advantage of zeolites is their regular structure, a large internal specific surface
(around 600–800 m 2 /g), pores of the same size and good thermal stability. One of
the major factors determining the selection of charging is its aerodynamic resistance
which is directly related to the porosity and humidity of charging. A higher
aerodynamic resistance of charging is obtained upon increasing charge humidity and
reducing fraction. It can be stated, therefore, that the major factors having an influence
of filter treatment efficiency and the amount of used energy are the selection
of filter charge and its humidification. For a standard bio-filter, pressure losses may
reach from 1 to 10 hPa. This chapter analyses the structural peculiarities of air treatment
bio-filters and presents related proposals aimed at reducing the aerodynamic
resistance of these devices (Reza et al. 2005; Ruokojarvi et al. 2001; Schwarz et al.
2001; Sercu et al. 2005 et al.).
Chapter 3 The Structure of a Granulated Charge Layer overviews literature on
the properties of this type of charging and describes methods for determining the
porosity of a granulated charge layer. Recently, methods for research on the granulated
charge structure have been developed and improved which can be applied
for investigating prospective high-temperature nuclear reactors with gas cooling
(Morales et al. 1951; Schuter, Vortmeyer 1981; Аэров 1951; Аэров, Тодес 1968;
Аэров и др. 1979; Lyczkowski 1982; Бесков, Абаев 1980). This chapter presents
the dependences of the porosity of charging on its form which shows a lesser porosity
of a layer of cylinder-shaped granules than that of a layer of granules having
a round form. It also discusses the results of research carried out by Zavelev, Robl