Filters pilot scale

Materials suitable as filter aids include diatomaceous earth, expanded perilitic rock, asbestos, ceUulose, nonactivated carbon, ashes, ground chalk, or mixtures of those materials. The amount of body feed is subject to optimisa tion, and the criterion for the optimisa tion depends on the purpose of the filtration. Maximum yield of filtrate per unit mass of filter aid is probably most common but longest cycle, fastest flow, or maximum utilisation of cake space are other criteria that requite a different rate of body feed addition. The tests to be carried out for such optimisation normally use laboratory or pilot-scale filters, and must include variation of the filtration parameters such as pressure or cake thickness in the optimisation. 

Filtration experiments are typically conducted in pilot scale equipment and generally tests are conducted either at constant pressure or constant rate to determine axo, as well as s and Rf, for a given sludge and filter medium. Such tests provide empirical information that will enable the time required tor the pressure drop to reach the desired level for a specified set of operating conditions to be determined. In the initial stages of filtration, the filter medium has no cake. Furthermore, Ap is not zero, but has a value that is a function of the resistance of the medium for a given flowrate. This initial condition can be stated as ... 

C Lehcimaki, M. Performance of Ventilation Filters Pilot Field Tests, Material Test and full Scale Field Test. Tampere, Finland, December 18, 1997,... 

Lu XJ, Liu L, Yang B, Chen JH (2009) Reuse of printing and dyeing wastewater in processes assessed by pilot-scale test using combined biological process and sub-filter technology. J Clean Prod 17 111-114... 

It is also important to recognize the interaction between the scaling parameters. Simply multiplying an existing process by the next scale-up factor may lead to errors. For example, if a single 10-in. filter is used at 66% capacity in the pilot scale, a four-fold increase in scale does not require four 10 in. filters. Rather, three 10 in. filters or a single 30-in. filter can be used at 88 /o capacity. 

The dried fermentation residues were broken up to pass through a 6-mm screen and mixed three times by the method of cone and quarter mixing. The dried and screened HDG (-32 kg) was available for poultry-feeding trials (Table 3). The supernatant from the centrifugation step and filtrate from the filter belt were not evaporated to form concentrated syrup to be added to the dried HDG to form HDGS because of lack of pilot-scale equipment to accomplish the evaporation step. 

Gravity filters are seldom used in the process industries because they offer low filtration rates, however, simple Nutsch filters are sometimes found in the pharmaceutical industry at pilot scale. The Nutsch filter is a tank with a perforated base on which a filter cloth can be supported. The feed slurry liquid filters through the cake and cloth under its own weight. Although these units are low cost, they are labor intensive to operate, cannot be contained for protection of the product or the operator, and are slow. 

Filtration devices that utilize high-pressure forces are capable of reducing moisture in the filter cake to about 20 percent, but capital and operating costs are high for these devices. Other newly developed techniques that have been tested on a pilot scale include an ultrahigh-g centrifuge, which generates forces... 

Estimate the ozone dose needed to disinfect a filtered secondary effluent to an MPN (most probable number) value of 240/100 mL using the following disinfection data obtained from pilot-scale... 

An example of a solid-liquid phase separation - often referred to as a mechanical separation - is filtration. Filters are also used in gas-sohd separation. Filtration may be used to recover liquid or sohd or both. Also, it can be used in waste-treatment processes. Walas [6] describes many solid-hquid separators, but we will only consider the rotary-drum filter. Reliable sizing of rotary-drum filters requires bench and pilot-scale testing with the slurry. Nevertheless, a model of the filtering process will show some of the physical factors that influence filtration and will give a preliminary estimate of the filter size in those cases where data are available. 

The reviewed mill-scale examples prove NF spEal-wound modules to be useful in the treatment of pulp and paper mill effluents but at the same time it must be concluded that extensive pretreatments are needed when spEal wound modules are utilized. This has also been pointed out in many pilot-scale studies where multilayer filters [108], flotation, and tight carEidge filters have been used before spEal wound modules [109]. Despite efficient pretreatments, the flux has commonly been only 10-40 L/(m h) when NF membranes are used in spEal-wound modules. 

Pilot-scale particle collection efficiency has been found to be similar to the cold and dry experiments over 300 hours filtration time, Figure 12 presents a relatively constant pressure drop over time for the hot and dry experiments conducted on the pilot-scale filter under a gas flowrate of 20 Nm /h (80 Nm /hr/m ), with a particle load of 3000 mg/Nm and using Ottawa sand as the filtering media. Deep holes on Figure 12 are air pulses to back-flush the solids plugging the exits. 

This research is being performed in two phases evaluation of pressure drop and flow characteristics of cold flow models of the filter and collection efficiency tests with a pilot-scale filter coupled to a 4.S tonne per day biomass gasifier. In this paper we describe three fluid dynamic design features developed in the cold flow model that improve performance of the Alter. 

As the design of adsorptive filters is difficult and complexed, and proper infarma-tions are not always sufficient, the best solution to establish the work parameters of filters is to test a series of carbons on a pilot - scale in dynamic conditions. The studies are expensive and time-consuming, thus it is proposed to evaluate granular carbons in static conditions according to some tests [25—29]. Further studies may be conducted in dynamic conditions. It seems, that the best solution, is to carry out comparable studies of both static and dynamic adsorption which give a possibility to predict a behaviour of carbons in dynamic conditions basing on static studies. 

According to the above, most tested carbons may be used as filter beds in water treatment plants. The choice of carbon should be carried out on the basis of indicators, analysis of costs, possibiUty and rate of regeneration. Adsorption capacity and parameters of work should be determined by pilot scale studies. Studies of testing methods and model adsorption should give standard carbons for removal of characteristic groups of water pollutants. Both powdered and granular carbons should be used, the former to pre—treatment or periodically at the time of peak load, and the latter, to final water treatment in compensated conditions. 

This pilot-scale has confirmed our earlier observations from full-scale drinking-water treatment plants. Such a detailed and systematic analysis of the amino acid concentrations allow one to monitor the degree of colonization of the filter media. Such colonization presents a problem when it is not wanted or improperly controlled. In these cases, it may be possible to disinfect and then wash the filtey media to decrease the release of amino acids. 

Milk bottling plant DAF+upflow anaerobic filter (UAF) 38-50% BOD5 (DAF) >90% BOD5 (UAF) >85% COD (UAF) Pilot scale Kasapgil et al. (1994)... 

The U.S. Bureau of Mines has tested a pilot-scale sulfur dioxide to sulfur conversion process which involves initial absorption of sulfur dioxide in an aqueous solution of citric acid, H0C(CH2C02H)2C02H, and sodium citrate (Fig. 13.11). This solution is then contacted with hydrogen sulfide to reduce the sulfur dioxide to elemental sulfur, which is then readily filtered from the resulting slurry (Eqs. 13.41-13.43). 

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