Efficiency continuous settling

Batch-stirred vessels are most often used in treating material with powdered activated carbon (72). The type of carbon, contact time, and amount of carbon vary with the desired degree of purification. The efficiency of activated carbon may be improved by applying continuous, countercurrent carbon—Hquid flow with multiple stages (Fig. 3). Carbon is separated from the Hquid at each stage by settling or filtration. Filter aids such as diatomaceous earth are sometimes used to improve filtration. 

Since the efficiency of this washing is dependent upon the degree of settling, the checkers recommend that washing with 50-mL batches of ether be continued until the smell of the alcohol is no longer detectable on a sample of the dry salts. 

As shown in Table 11.3, the concentrations of trace elements in the water column is - despite anthropogenic pollution - extremely small (10 11 - 10 7 M) illustrating the remarkable efficiency of the continuous "conveyor belt" of the settling adsorbing and scavenging particles. The sedimentary record reflects the accumulation of trace elements in sediments and a profile of concentration vs sediment-depth (or age) gives a "memory record" on the loading in the past (Fig. 11.9). 

The cold filtrates (solutions of monochlorourea) are transferred to a 3-1. two-necked flask immersed in an ice-salt bath. The flask is equipped with a slip- or mercury-sealed mechanical stirrer and an efficient reflux condenser. To the flask are added 500 g. of ice, 100 ml. of glacial acetic acid, and 136 g. (2.0 moles) of cyclopentene (or 1.43 times the weight increase in grams during introduction of the chlorine) (Note 4). Mechanical stirring is begun, and is continued while the flask is kept packed in ice until the cyclopentene (the top layer) disappears and a heavy oil settles to the bottom (Note 5). 

Conditions favoring efficient separation of flocculent metal precipitates in a basin include a low surface overflow rate, adequate depth, and inlet and outlet designs for a uniform velocity field with minimal short circuiting or stagnation. Solids separation is likely to limit the overall efficiency of metals removal in treatment, so pilot studies include batch and continuous flow settling column studies.18... 

Horizontal separators normally are more efficient at handling large volumes of gas than vertical types since liquid droplets fall perpendicular to the gas flow in the gravity settling section, and are more easily settled out of the gas continuous phase. Also, since interface area is larger in a horizontal separator, it is easier for gas bubbles, which come out of solution as liquid approaches equilibrium, to reach the vapor space. 

The reactive mixture is withdrawn from the top of the reactor into separation tower 3. The hydrolysate from the top of the tower is sent into collector 5. From there it is sent through drying tower 6 filled with calcium chloride into neutraliser 7, which is loaded with a necessary amount of dry soda ash (continually or periodically, depending on the efficiency of the apparatus). The neutralised hydrolysate is sent into collector 8. Hydrochloric acid, which has been settled in the bottom part of tower 3, enters collector 4. 

In a 5-I. three-necked, round-bottomed flask fitted with an efficient stirrer (Note 1), a separatory funnel, and a thermometer in a well, is placed a solution of 500 g. (9.7 moles) of powdered 95 per cent sodium cyanide in 1200 cc. of water and 900 cc. (713 g., 12.3 moles) of acetone. The flask is surrounded by an ice bath and the solution is stirred vigorously. When the temperature falls to 150, 2100 cc. (8.5 moles) of 40 per cent sulfuric acid (Note 2) is added over a period of three hours, keeping the temperature between io° and 20°. After all the acid has been added the stirring is continued for fifteen minutes and then the flask is set aside for the salt to settle. Usually a layer of acetone cyanohydrin forms and is decanted and separated from the aqueous layer. The sodium bisulfate is removed by filtration and washed with three 50-cc. portions of acetone. The combined filtrate and acetone washings is added to the aqueous solution which is then extracted three times with 2 50-cc. portions of ether (Note 3). The extracts are combined with the cyanohydrin previously separated and dried with anhydrous sodium sulfate. The ether and acetone are removed by distillation from a water bath, and the residue is distilled under reduced pressure. The low-boiling portion is discarded and the acetone cyanohydrin is collected at 78-82°/i5 mm. The yield is 640-650 g. (77-78 per cent of the theoretical amount). 

These trajectory methods have been used by numerous researchers to further investigate the influence of hydrodynamic forces, in combination with other colloidal forces, on collision rates and efficiencies. Han and Lawler [3] continued the work of Adler [4] by considering the role of hydrodynamics in hindering collisions between unequal-size spheres in Brownian motion and differential settling (with van der Waals attraction but without electrostatic repulsion). The results indicate the potential significance of these interactions on collision efficiencies that can be expected in experimental systems. For example, collision efficiency for Brownian motion will vary between 0.4 and 1.0, depending on particle absolute size and the size ratio of the two interacting particles. For differential... 

In each solvent series,the partition coefficient of the sample can be finely adjusted by modifying the volume ratio of the components. The first series covers a broad range in both hydrophobicity and polarity continuously from M-hexane/methanol/water to n-butanol/water. The second series of chloroform/methanol/water provides moderate hydrophobicity and the third series of ferf-butyl methyl ether/w-butanol/acetonitorile/water is suitable for hydrophilic compounds. Most of these two-phase solvent systems provide near 1 1 volume ratios of the upper/lower phases, together with the reasonable range of settling times in 30 sec or less, so that they can be efficiently applied to HSCCC and other centrifugal CCC schemes. 

Oxygen profiles in the ocean do not continually decrease with depth (Fig. 1.4). A typical dissolved O2 profile exhibits a minimum that is positioned above 1000 m. The main processes that contribute to this profile are the rapid and efficient respiration of settling organic matter (with more than half being degraded between 100 and... 

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