Volume requirement

Also, although there are no selectivity data for the reaction, the selectivity losses would be expected to increase with increasing conversion. Complete conversion would tend to produce unacceptable selectivity losses. Finally, the reactor volume required to give a complete conversion would be extremely large. 

Dissolve 5 g. of phenol in 75 ml. of 10 per cent, sodium hydroxide solution contained in a wide-mouthed reagent bottle or conical flask of about 200 ml. capacity. Add 11 g. (9 ml.) of redistilled benzoyl chloride, cork the vessel securely, and shake the mixture vigorously for 15-20 minutes. At the end of this period the reaction is usually practically complete and a sohd product is obtained. Filter oflf the soUd ester with suction, break up any lumps on the filter, wash thoroughly with water and drain well. RecrystaUise the crude ester from rectified (or methylated) spirit use a quantity of hot solvent approximately twice the minimum volume required for complete solution in order to ensure that the ester does not separate until the temperature of the solution has fallen below the melting point of phenyl benzoate. Filter the hot solution, if necessary, through a hot water funnel or through a Buchner funnel preheated by the filtration of some boiling solvent. Colourless crystals of phenyl benzoate, m.p. 69°, are thus obtained. The yield is 8 g. 

Example Sulfuric acid has the molecular weight 98.08. If the concentrated acid assays 95.5% and has the specific gravity 1.84, the volume required for 1 liter of a 0.1 molar solution is... 

Titrations conducted with microliter or picoliter sample volumes require a smaller absolute amount of analyte. For example, diffusional titrations have been successfully conducted on as little as 29 femtomoles (10 mol) of nitric acid. Nevertheless, the analyte must still be present in the sample at a major or minor level for the titration to be performed accurately and precisely. 

Scale of Operation Atomic absorption spectroscopy is ideally suited for the analysis of trace and ultratrace analytes, particularly when using electrothermal atomization. By diluting samples, atomic absorption also can be applied to minor and major analytes. Most analyses use macro or meso samples. The small volume requirement for electrothermal atomization or flame microsampling, however, allows the use of micro, or even ultramicro samples. 

The total stationary-phase volume required to process a given feed stream is proportional to the inlet concentration and volume of the feed. For example, for a typical inlet concentration of protein of 10 g/L, in a 100 L volume of feed, a column volume of at least 100 L is needed for size-exclusion chromatography. In comparison, an ion-exchange column having an adsorption capacity of 50 g/L would only require 20 L of column volume for the same feed. 

Dehydration. Use of molecular sieve driers for final clean-up of the carbon oxides and water in the synthesis gas to less than 1 ppm levels has gained prominence in low energy ammonia plant designs. The sieves are usually located at the interstage of the synthesis gas compressor to reduce volume requirements. The purified make-up gas can then be combined with the recycle and routed direcdy to the converter. 

In most cases volume requirement is the primary consideration for selecting the most cost-effective process. However, in many cases a lower volume process may be used during initial phases of a program and then be replaced by a higher volume process when the product has gained field acceptance. 

These reactions tend to give few by-products. The main by-product in each case is the sulfide, RSR, which amounts to less than 3—5% of the thiols produced. Some of the sulfides produced have appHcations, although they tend to be much smaHer-volume requirements than the amounts produced. The sulfides can be incinerated for disposal, assuming that the incineration facility can handle high sulfur feedstocks. 

Fig. 4. Schematic of the Closed Container Sampling technique used in the Baxter PARAMAX analy2er showing (a) the collection tube with bar-coded label being brought into sampling position under the caimula (b) the tube raised so that the caimula has penetrated the stopper (c) the sample sensing probe coming through the caimula to aspirate the exact volume required for each assay and (d) after sampling, where the tube is lowered away from the cannula.

Salting-out crystalli tion operates through the addition of a nonsolvent to the magma ia a crystallizer. The selection of the nonsolvent is based on the effect of the solvent on solubiHty, cost, properties that affect handling, iateraction with product requirements, and ease of recovery. The effect of a dding a nonsolvent can be quite complex as it iacreases the volume required for a given residence time and may produce a highly nonideal mixture of solvent, nonsolvent, and solute from which the solvent is difficult to separate. 

Whether a vessel is called an evaporator or a crystallizer depends primarily on the criteria used in arriving at its sizing. In an evaporator of the salting-out type, sizing is done on the basis of vapor release. In a ciystaUizer, sizing is normally done on the basis of the volume required for crystallization or for special features required to obtain the proper produc t size. In external appearance, the vessels could be identical. Evaporators are discussed in Sec. 11. 

An anaerobic digester is a no-recycle complete mix reactor. Thus, its performance is independent of organic loading but is controlled by hydraulic retention time (HRT). Based on kinetic theoiy and values of the pseudo constants for methane bac teria, a minimum HRT of 3 to 4 days is required. To provide a safety factor and compensate for load variation as indicated earlier, HRT is kept in the range 10 to 30 days. Thickening of feed sludge is used to reduce the tank volume required... 

Determining the core size. TDK rates its cores by the amount of power that can be handled by the core in a one-transistor forward converter. Its volume requirements are very similar to a flyback converter. The EPC core that rated at 15 W or greater is the EPC 17 core size. The part numbers for this assembly are core, PC40EPC17-Z bobbin,BER17-llllCPH and clamp, FEPC17-A. 

Process steam requirements can be controlled at a suitable pressure and volume required by the process and maintained at these conditions by extraction or induction turbines. 

Design concerns for drive cycle emission control include canister volume requirements, purge volume effects, and the use of return vs. retumless fuel systems. 

Density Separation Storage Volume Required Size Modification or Separation Size Reduction Dissolution... 

Determine the reaetor volume required to proeess 10,000 Ib/hr of benzene (the feed is pure benzene) as a funetion of the total eonversion. 

The reactor volume required to process 10,000 Ib/hr of benzene is estimated from Table 5-13. For a total conversion of 50.8%,... 

They further determined the ratio of the dispersion reaetor volume to the plug flow reaetor volume required to aeeomplish the same degree of eonversion for several values of the dimensionless dispersion parameter /uL. Figure 8-39 shows the results of Equation 8-147... 

Choose a fermenter volume required based on tlie desued capacity. 

A workshop has a fabric and ventilation sensible heat loss of 30 kW, and the process requires that the room be maintained at 22 °C dry bulb. Determine the supply air volume required at 34 "C in order to maintain the space at design conditions. 

For a new process plant, calculations can be carried out using the heat release and plume flow rate equations outlined in Table 13.16 from a paper by Bender. For the theory to he valid, the hood must he more than two source diameters (or widths for line sources) above the source, and the temperature difference must be less than 110 °C. Experimental results have also been obtained for the case of hood plume eccentricity. These results account for cross drafts which occur within most industrial buildings. The physical and chemical characteristics of the fume and the fume loadings are obtained from published or available data of similar installations or established through laboratory or pilot-plant scale tests. - If exhaust volume requirements must he established accurately, small scale modeling can he used to augment and calibrate the analytical approach. 

Table 13.17 lists some of the important considerations for the different fume capture techniques. From the point of view of cost effectiveness, the usual preference is source collection or a low-level hood, provided an acceptable scheme can be developed within the process, operating, and layout constraints. The cost of fume control systems is almost a direct function of the gas volume being handled. Flence, the lower volume requirements for the source capture or low-level hood approach often results in significant capital and operating cost savings for the fume control system. 

At a constant speed, a constant volume of gas (at suction conditions of pressure and temperature) will be drawn into the cylinder. As the flow rate to the compressor decreases, the suction pressure decreases until the gas available expands to satisfy the actual volume required by the cylinder. When the suction pressure decreases, the ratio per stage increases and therefore the discharge temperature increases. In order to keep from having too high a discharge temperature, the recycle valve opens to help fill the compressor cylinder volume and maintain a minimum suction pressure. 

As flow rate to the compressor increases, the suction pressure rises until the volume of gas at actual conditions of temperature and pressure compressed by the cylinder equals the volume required by the cylinder. A flare valve is needed to keep the suction pressure from rising too high and overpressuring the suction cylinder, creating too high a rod load or increasing the horsepower requirements beyond the capability of the driver (see Chapter 11 for further discussion). 

Let us consider a simple self-avoiding walk (SAW) on a lattice. The net interaction of solvent-solvent, chain-solvent and chain-chain is summarized in the excluded volume between the monomers. The empty lattice sites then represent the solvent. In order to fulfill the excluded volume requirement each lattice site can be occupied only once. Since this is the only requirement, each available conformation of an A-step walk has the same probability. If we fix the first step, then each new step is taken with probability q— 1), where q is the coordination number of the lattice ( = 4 for a square lattice, = 6 for a simple cubic lattice, etc.). 

Water purification and recycling is now a major industry.The method of treatment depends on the source of the water, the use envisaged and the volume required. Luckily the human body is very tolerant to changes in the composition of drinking water, and in many communities this may contain 0.5 gl or more of dissolved solids (Table 14.7). Prior treatment may consist of coagulation (by addition of alum or chlorinated FeS04 to produce floes of Al(OH)3 or Fe(OH)3), filtration, softening (removal of... 

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