The results of experiments on practical suitability of a biofilter packing made of natural materials – pinecones are provided. Geometric characteristics of a random packing of pine cones are calculated and compared with other types of packings of artificial and natural materials. Aerodynamic tests of the packing are carried out and obtained data are compared with the data for other packings. Some recommendations on improving the performance characteristics of the packing are suggested.
The hydraulic resistance of packing is studied, intended for use in cassette biofilters. The proposed packing of lavsan monofibers 1 mm thick has minimal hydraulic resistance compared with other known forms of packing used in practice. Values of hydraulic resistance coefficient ζ are obtained for dry packing. The value of ζ is 0.3 with values of criterion Re > 1400.Biological air cleaning is the most economic and expedient method for purification from organic compounds and odorants in enterprises for the production of dies, textiles, in reprocessing, furniture, and other enterprises [1,2].Air with a high content of biochemically readily oxidizable contaminants is passed through a layer of packing, to whose surface a film of micro-organisms is applied. Here contaminants dissolved in air are transported into a biological film, where they serve as a substrate for micro-organisms, as a rule aerobic, processing it to final products, i.e., water and carbon dioxide [2].Substrate processing intensity is mainly determined by the rate of its supply from air into a biological film, and in turn it depends on the gas dynamic flow conditions in a two-phase system, and this depends directly on the packing matter. Thus, the packing used should exhibit specific geometrical properties, i.e., have a developed surface and minimum hydraulic resistance.Currently in industry for charging cassette biolfilters lump materials are used: lumps of bark, zeolite granules, wood shavings, silica gel granules, etc.[2].These packings have significant aerodynamic resistance to the flow of gas being cleaned, which has a negative effect on energy properties of gas cleaning from harmful impurities. A biomass of micro-organisms is lost due to considerable aerodynamic resistance, i.e., its breaks away and is carried off by the gas being cleaned. The unfavorable effect of all these undesirable processes is reduced by several factors with the use of regular structured packing, including that indicated by us.Tests have been carried out in a unit whose layout is presented in Fig. 1. The test equipment was a horizontal channel of square cross section (130 × 130 mm 2 ) and length of 2500 mm. The maximum air flow rate (350 m 3 /h) was provided by a fan; the corresponding flow rate V g was 0-5 m/sec in terms of the free equipment cross section. The air volumetric flow rate as determined by a pneumatic method [3]. Air temperature was 20°C, barometric pressure was 101.3 kPa. The loss of head in the packing layer was measured by a pneumatic method using an inclined MMN 2400 micromanometer [4].The test packing (Fig. 2) was made in the form of a package of alternating corrugated and flat elements. Similar packing is used in accomplishing processes of heat and mass transfer [5]. Packing elements were made in the form of a grid of lavsan monofibers with thickness d = 1 mm. The flat plates are rectangular in shape, with a size of 130 × 25 mm 2 , and the corrugated plates have straight corrugations with a height of 5 mm. A package consisting of 30 alternating plates ha...
A method for producing biodiesel with supercritical parameters is described and the advantages of the method vis-à-vis the catalytic methods are determined. An experimental setup for obtaining fatty acid methyl esters (FAME) is presented with a description of its basic units. Arrays of parameters that determine the efficiency and intensity of the process as a whole are obtained by a series of experiments. The rate of formation and yield of FAME depending on these parameters are determined, and then the optimal parameters of process implementation for producing biodiesel in supercritical methanol are presented. The feasibility of producing biodiesel with supercritical parameters is shown.At the present stage of development, sustained, economically feasible, and ecologically clean energy sources are essential. In this context, it is urgent to search for and introduce alternative energy sources. One of the directions of modern energy development is utilization of biofuel. A basic component of biodiesel fuel is fatty acid methyl esters (FAME), which are used essentially as additives to diesel fuel. Even a small addition of biodiesel to diesel fuel reduces noxious emissions by 50-70% [1, 2].The FAME production technology consists in transesterification of vegetable oils (rapeseed, sunflower, palm, etc.) or alga mass oils with methanol [3,4]. Transesterification is carried out in the presence of catalysts, and since this reaction is reversible, 10-20 fold stoichiometric excess of methanol is required to achieve acceptable conversions of the original oil. Homogeneous catalysts, namely alkali metal hydroxides [5], or heterogeneous catalysts based on oxides of Group II-VI metals and lanthanides (rare earth elements) [6] are used.A demerit of homo-catalytic processes is that homogeneous catalysts are not amenable to regeneration and are therefore wastes after each process cycle. This demerit can be remedied by using heterogeneous catalysts. However, heterogeneous catalysts for transesterification are active only at high temperatures (250-350°C). At such temperatures, side reactions occur on the surface of oxide catalysts with the involvement of thermally labile oil components containing fragments of unsaturated fatty acids (oleic, linoleic, etc.) with the formation of aromatic compounds and, finally, coke which blocks the most active centers. So hourly output of FAME does not exceed 2.5-3.0 liters/(liter of catalyst⋅h). Also, because of deposition of by-products on the catalyst, the latter needs to be regenerated periodically in air current at 800°C. As a result, the cost of biodiesel fuel is 10-15% higher than that of petroleum diesel oil [7].Noncatalytic FAME production methods do not suffer from the demerits described above. One of such methods is the method of supercritical condition where use is made of anomalously high dissolving power of substances that lie above the critical point. Vegetable oils are transesterified without a catalyst at temperatures and pressures higher than the critical parameters of methanol (T ...
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