Pilot-range

Oral LD50 (gavage) - pilot range study first chemical administration to fasting animal in varying doses, observation, and autopsy after death. 

Fig. 6.15 Fine chemical microreactor plant for laboratory- and pilot-range operation, completely assembled (lower image) and microreactor-system core (upper image). (Source IMM.)...

Aromatic and Nonaromatic Hydrocarbon Separation. Aromatics are partially removed from kerosines and jet fuels to improve smoke point and burning characteristics. This removal is commonly accompHshed by hydroprocessing, but can also be achieved by Hquid-Hquid extraction with solvents, such as furfural, or by adsorptive separation. Table 7 shows the results of a simulated moving-bed pilot-plant test using siHca gel adsorbent and feedstock components mainly in the C q—range. The extent of extraction does not vary gready for each of the various species of aromatics present. SiHca gel tends to extract all aromatics from nonaromatics (89). 

Eor design of a large-scale commercial extractor, the pilot-scale extractor should be of the same type as that to be used on the large scale. Reflable scale-up for industrial-scale extractors still depends on correlations based on extensive performance data collected from both pilot-scale and large-scale extractors covering a wide range of Hquid systems. Only limited data for a few types of large commercial extractors are available in the Hterature. 

Comparisons of the complete heat-transfer model with pilot-scale rotary kiln data are shown iu Figure 5 (21) for moisture levels ranging from 0 to 20 wt %. The tremendous thermal impact of moisture is clearly visible iu the leveling of temperature profiles at 100°C. 

The first commercial plant to use CYANEX 272 became operational in 1985. An additional three plants were constmcted between 1985 and 1989. Of the four, one is in South America and three in Europe. An additional three plants have been built two in Europe (1994) and one in North America (1995). Approximately 50% of the Western world s cobalt is processed using CYANEX 272. Both high purity salts and electrolytic cobalt metal are recovered from solutions ranging in composition from 30 g/L each of cobalt and nickel to 0.2 g/L Co, 95 g/L Ni Operating companies usually regard use of CYANEX 272 as confidential for competitive reasons and identities cannot be disclosed. CYANEX 272 is being evaluated on the pilot-plant scale in many additional projects involving the recovery of cobalt and other metals. 

The way a pilot plant is designed affects its cost, operabiUty, and effectiveness. AH operating ranges may not yet be fully defined at the initial design stage, but a reahstic preliminary range is required before the design is commenced, as is a clear definition of the pilot plant s purpose. 

Pilot plant costs range from 10,000 to 10,000,000, but the majority are typically in the range of 50,000 to 250,000, assuming an existing facihty is available to house them. There are three basic methods for estimating the costs to design and constmct a pilot plant similarity, cost ratios, and detailed labor and materials. 

Additional definition of the operative mechanisms can obviate the need for the larger unit. It maybe possible to assess limitations in a smaller unit that has only a few injection points on the distributor. The unit could be used to evaluate distributor designs that permit a wide range of acceptable operating conditions. However, if the acceptable range proves smaller than desired, the larger pilot unit would then be needed to estabUsh acceptable performance. 

Design criteria for carbon adsorption include type and concentration of contaminant, hydrauhc loading, bed depth, and contact time. Typical ranges are 1.4—6.8 L/s/m for hydrauhc loading, 1.5—9.1 m for bed depth, and 10—50 minutes for contact time (1). The adsorption capacity for a particular compound or mixed waste stream can be deterrnined as an adsorption isotherm and pilot tested. The adsorption isotherm relates the observed effluent concentration to the amount of material adsorbed per mass of carbon. 

Reverse Osmosis. In reverse osmosis (qv), a solution or suspension flows under pressure through a membrane the product is withdrawn on the other side. This process can treat dissolved soHds concentrations ranging from 1 mg/L to 35 g/L (14). The principal constraint is the requirement that the waste material be relatively nonfouling. Recent advances have been mosdy in membrane development, and pilot studies are required (15). Energy costs can be significant, and it is frequently necessary to pretreat influent in order to minimize fouhng. Reverse osmosis can deal with particles < 1 to 600 nm in size. 

Activated carbons for use in Hquid-phase appHcations differ from gas-phase carbons primarily in pore size distribution. Liquid-phase carbons have significantly more pore volume in the macropore range, which permits Hquids to diffuse more rapidly into the mesopores and micropores (69). The larger pores also promote greater adsorption of large molecules, either impurities or products, in many Hquid-phase appHcations. Specific-grade choice is based on the isotherm (70,71) and, in some cases, bench or pilot scale evaluations of candidate carbons. 

In the United States the Clean Coal Technology program was created to develop and demonstrate the technology needed to use coal in a more environmentally acceptable manner. Activities range from basic research and estabUshing integrated operation of new processes in pilot plants through demonstration with commercial-scale equipment. 

Typically, a filter cake or precoat is built up on the filter septa to prevent blinding, short filter cycle times, and cosdy cleaning of the septa. Then diatomite is added as body feed to the Hquid to be filtered so that the permeabiHty of the filter cake may be maintained. Filler aid permeabiHty of diatomite ranges from 0.06 to 30 lnF. At the end of the filter cycle the filtrate is clear and the soHds are retained in the soHd or semisoHd diatomite filter cake. The type and amount of diatomite for precoat and body feed are normally deterrnined by pilot studies (18,19). 

Adsorption. Adsorption (qv) is an effective means of lowering the concentration of dissolved organics in effluent. Activated carbon is the most widely used and effective adsorbent for dyes (4) and, it has been extensively studied in the waste treatment of the different classes of dyes, ie, acid, direct, basic, reactive, disperse, etc (5—22). Commercial activated carbon can be prepared from lignite and bituminous coal, wood, pulp mill residue, coconut shell, and blood and have a surface area ranging from 500—1400 m /g (23). The feasibiUty of adsorption on carbon for the removal of dissolved organic pollutants has been demonstrated by adsorption isotherms (24) (see Carbon, activated carbon). Several pilot-plant and commercial-scale systems using activated carbon adsorption columns have been developed (25—27). 

The yield in a chemical reaction determines the quantities of materials in the material balance. Assumed yields are used to obtain approximate exploratoiy estimates. In this case, possible ranges should be given. Firmer estimates require yields based on laboratoiy or, preferably, pilot-plant work. 

Table Type This is a simple flat metal sheet with slightly upturned edges and jacketed on the underside for coolant flow. For many years this was the mainstay of food processors. Table types are still widely used when production is in small batches, when considerable batch-to-batch variation occurs, for pilot investigation, and when the cost of continuous devices is unjustifiable. Slab thicknesses are usually in the range of 13 to 25 mm (V2 to 1 in). These units are homemade, with no standards available. Initial cost is low, but operating labor is high.

Pilot plant tests are conducted using the actual plant materials since small amounts of contaminents can have significant effects on throughput and efficiency. These tests are usually conducted in columns ranging from 0.075-0.15 m diameter the column height (and therefore number of compartments) should be sufficient to accomplish the separation desired this may require several iterations on column height. 

Continuously operated, small-scale or pilot-plant thickeners, ranging from 75 mm diameter by 400 mm depth to several meters in diameter, are also effectively used for sizing hill-scale equipment. This approach requires a significantly greater volume of sample, such as... 

Discs range in size from laboratory models 30 cm in diameter up to production units of 10 meters in diameter with throughputs of 100 ton/hr. Figure 20-82 shows throughput capacities for discs of varying diameter tor different applications and formulation feed densities. When scaling up from laboratoiy or pilot tests it is usual to keep the... 

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