Ceramic filters

In earlier research the alignment operation was applied to CNTs in the form of a CNT-polymer resin [24] or CNT suspended in a solvent [25]. In the method developed by Ajayan et al. [24], purified MWCNTs were dispersed in an epoxy resin which was cut with a diamond knife and a microtome in order to obtain aligned CNTs. De Heer et al. [25] used a 0.2 (im pore ceramic filter in order to create an MWCNT suspension in ethanol, and to obtain a black deposit which was transferred to a plastic surface (Delrin or Teflon) by pressing the filter onto the polymer. However, only a moderate degree of orientation and uniformity in length of the CNTs was achieved by this method. 

The small particles are reported to be very harmful for human health [98]. To remove particulate emissions from diesel engines, diesel particulate filters (DPF) are used. Filter systems can be metallic and ceramic with a large number of parallel channels. In applications to passenger cars, only ceramic filters are used. The channels in the filter are alternatively open and closed. Consequently, the exhaust gas is forced to flow through the porous walls of the honeycomb structure. The solid particles are deposited in the pores. Depending on the porosity of the filter material, these filters can attain filtration efficiencies up to 97%. The soot deposits in the particulate filter induce a steady rise in flow resistance. For this reason, the particulate filter must be regenerated at certain intervals, which can be achieved in the passive or active process [46]. 

The separation method targets recovery of the aqueous phase from oil/water mixtures of microbial reactions by filtration through a ceramic filter module [154], The invention particularly referred to a two-phase system resulting from a process used for production of 2,6-naphthalenedicarboxylic acid using S. paucimobilis AK2M16 (PERM P-13996). The aqueous phase is said to be recovered free of microbial cells and oil. Although, it is mentioned that the reaction product can be recovered readily in high yield, the need for an additional unit operation looks obvious. 

High-temperature gas cleaning (in particular, gas filtration using metal or ceramic filters and also the removal of especially sulfur species)... 

Ceramic Filter. The ceramic filter collects, volatilizes, and destroys particulates and condensible organics emitted from industrial process streams, such as paint spray, lost foam casting, condensible organics, tenter frames, and cured rubber... 

Gillot, J. and D. Garccra. 1984. New ceramic filter media for cross-flow microfiltration and ultrafiltration. Paper presented at Filtra 84 Conference, 2-4 October 1984, Paris. 

Glass tube with cooling mantle, equipped at the bottom with a ceramic filter plate to allow easy separation of the catalyst upon reaction, diameter 4 cm... 

Examples of computer reconstructed DPF porous media are given in Fig. 5 and encompass all currently available filtration media extruded ceramic filters (including reaction formed media as cordierite and grain-sintered media as SiC), fibrous filters, foams and sintered metal powder/wiremesh. 

Konstandopoulos, A. G., and Kostoglou, M. A mathematical model of soot oxidation on catalytically coated ceramic filters . Advances in Vehicle Control and Safety (AVCS 98), Amiens, France, July 1-3, 1998. 

Coarse (dP = 50-100 pm) porous disks are the most frequently applied diffusers in large-scale drinking water treatment systems (Masschelein, 1994). They are seldom used in industrial waste water treatment applications. The reason is that blocking or clogging can easily occur, e. g. by means of precipitation of chemicals, like carbonates, aluminum or ferrous oxides, manganese oxides, calcium oxalate or organic polymers. This is also valid for ceramic filter tubes, which are sometimes used as mass transfer systems in drinking water applications. 

Ceramic filters, which are often combined with carbon filters, remove bacteria, asbestos, and sediment. 

Another crop of product was obtained from the methanol liquors as follows. The liquors were added to a reactor of 20 gallon (91 liters) capacity and the solvent was distilled off for 9 hours until solid appeared. The mixture was then cooled to 15° to 20°C over 1 3/4 hours using cooling water in the jacket of the reactor. The mixture was cooled to 10°C using brine in the jacket and stirred at this temperature for 30 minutes. The product was then filtered on a ceramic filter and sucked well dry. The product on the filter was washed twice with methanol (5 kg each time) and sucked well dry. The product was dried in an air oven at 55°-60°C for 18 hours. The yield was 2.14 kg. This product may also have been acceptably pure but its purity was not investigated. It was therefore retained as crude product to be resubjected to recrystallisation with methanol. The yield for the recrystallisation was thus 12.1 kg from a consumption of 13.76 kg of crude product, that is 88%. The overall yield of pure product is 69.8% times 88%, that is, 61.4%. 

Bosch Based on HJS technology. Sinter ceramic filter with catalytic coating... 

To overcome this challenge, other filter designs and construction materials were tested, such as packed-bed filters [41], foam ceramic filters [39, 42—44], sintered ceramic filters [18, 45, 46], candle-type filters made from metal or ceramics [22, 47], or honeycomb structures made from steel [48]. Among the construction materials, the performance of high-temperature ceramics, such as SiC, Zr02, or SiC>2, was investigated [18, 45, 46, 49],... 

Fig. 15.5. Typical pressure drop and concentration-time curves of a diesel particulate trap in a closed gas-loop experiment with constant heating rate for the characterization of catalyst or filter performance for the combustion of diesel soot. Sintered SiC ceramic filter, without catalyst coating or fuel additive (from Ref. [46]).

Improvement of membrane separation technology has resulted in the isolation of MFGM-enriched material from commercially available products. A phospholipid-rich fraction can be extracted from whey (Boyd et al., 1999) and buttermilk (Sachedva and Buchheim, 1997) with a reported yield of 0.25 g of phospholipids/g of protein in buttermilk (Sachdeva and Buchheim, 1997). Microfiltration of whey derived from the Cheddar cheese process, using 0.2 pm ceramic filters results in a fraction containing two major phospholipids, phosphatidylcholine and phosphatidylethanolamine, and lesser amounts of phosphatidylinositol, phosphatidylserine, sphingomyelin and cerebrosides (Boyd et al., 1999). The phospholipid fraction separated from the total lipids contains a larger proportion of mono- and polyunsaturated fatty acids (mainly oleic, Cig i and linoleic, C ) compared to the total lipid and the neutral lipid fraction (Boyd et al., 1999). 

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