Fresh

In describing reactor performance, selectivity is usually a more meaningful parameter than reactor yield. Reactor yield is based on the reactant fed to the reactor rather than on that which is consumed. Clearly, part of the reactant fed might be material that has been recycled rather than fresh feed. Because of this, reactor yield takes no account of the ability to separate and recycle unconverted raw materials. Reactor yield is only a meaningful parameter when it is not possible for one reason or another to recycle unconverted raw material to the reactor inlet. By constrast, the yield of the overall process is an extremely important parameter when describing the performance of the overall plant, as will be discussed later. 

These polyethylbenzenes are recycled to the reactor to inhibit formation of fresh polyethylbenzenes. ... 

Forward-feed operation is shown in Fig. 3.12a. The fresh feed is added to the first stage and fiows to the next stage in the same direction as the vapor flow. The boiling temperature decreases from stage to stage, and this arrangement is thus used when the... 

Parallel-feed operation is illustrated in Fig. 3.12c. Fresh feed is added to each stage, and product is withdrawn from each stage. The vapor from each stage is still used to heat the next stage. This arrangement is used mainly when the feed is almost saturated, particularly when solid crystals are the product. 

One further problem remains. Most of the n-butane impurity which enters with the feed enters the vapor phase in the first separator. Thus the n-butane builds up in the recycle unless a purge is provided (see Fig. 4.13a). Finally, the possibility of a nitrogen recycle should be considered to minimize the use of fresh nitrogen (see Fig. 4.136). 

Cold shot or hot shot. Injection of cold fresh feed for exothermic reactions or preheated feed for endothermic reactions to inter-... 

Compaction occurs when continuous sedimentation results in an increase of overburden which expels pore water from a sediment package. Pore space will be reduced and the grains will become packed more tightly together. Compaction is particularly severe in clays which have an extremely high porosity of some 80% when freshly deposited. 

In a normal pressure regime the pressure in a hydrocarbon accumulation is determined by the pressure gradient of the overlying water (dP / dD), which ranges from 0.435 psi/ ft (10 kPa/m) for fresh water to around 0.5 psi/ft (11.5 kPa/m) for salt saturated brine. At any depth (D), the water pressure (PJ can be determined from the following equation, assuming that the pressure at the surface datum is 14.7 psia (1 bara) ... 

Possible water sources for injection are sea water, fresh surface water, produced water or aquifer water (not from the producing reservoir). Once it has been established that there is enough water to meet demand (not an issue in the case of sea water), it is important to determine what type of treatment is required to make the water suitable for injection. This is investigated by performing laboratory tests on representative water samples. 

The system compares its own values for good and a bad magnetic particle suspensions with the actually measured values. The system values are stored in the form of reference curves for a fresh MP-suspension used on the machine and the used MP-suspension which has to be changed. 

Fig. Vni-11. ESCA spectrum of A1 surface showing peaks for the metal, A1(0), and for surface oxidized aluminum, Al(III) (a) freshly abraided sample (b) sample after five days of ambient temperature air exposure showing increased A1(III)/A1(0) ratio due to surface oxidation. (From Instrument Products Division, E. I. du Pont de Nemours, Co., Inc.)...

The foregoing is an equilibrium analysis, yet some transient effects are probably important to film resilience. Rayleigh [182] noted that surface freshly formed by some insult to the film would have a greater than equilibrium surface tension (note Fig. 11-15). A recent analysis [222] of the effect of surface elasticity on foam stability relates the nonequilibrium surfactant surface coverage to the foam retention time or time for a bubble to pass through a wet foam. The adsorption process is important in a new means of obtaining a foam by supplying vapor phase surfactants [223]. 

The approach that will be outlined here is due to Caratheodory [1] and Bom [2] and should present fresh insights to those familiar only with the usual development in many chemistry, physics or engineering textbooks. However, while the fonnulations differ somewhat, the equations that finally result are, of course, identical. 

Figure Bl.25.9(a) shows the positive SIMS spectrum of a silica-supported zirconium oxide catalyst precursor, freshly prepared by a condensation reaction between zirconium ethoxide and the hydroxyl groups of the support [17]. Note the simultaneous occurrence of single ions (Ff, Si, Zr and molecular ions (SiO, SiOFf, ZrO, ZrOFf, ZrtK. Also, the isotope pattern of zirconium is clearly visible. Isotopes are important in the identification of peaks, because all peak intensity ratios must agree with the natural abundance. In addition to the peaks expected from zirconia on silica mounted on an indium foil, the spectrum in figure Bl. 25.9(a)...

Arsenic(III) oxide is slightly soluble in water, giving a solution with a sweetish taste—but as little as 0.1 g can be a fatal dose (The antidote is freshly-precipitated iron(III) hydroxide.) The solution has an acid reaction to litmus, due to the formation of arsenic(III) acid ... 

Sodium hydrogensulphite, when freshly prepared, reacts with aldehydes to form crystalline addition compounds, for example... 

The disappearance of iodine at the end point is detected by the addition of fresh starch solution which gives a blue complex as long as iodine is present. 

The existence of anode and cathode areas can be seen by the following experiment. A few drops of phenolphthalein are added to a solution of potassium hexacyanoferrate(III) and hydrochloric acid added, drop by drop, until the solution is colourless. (The phenolphthalein turns pink due to hydrolysis of the potassium hexacyano-ferrate(III).) Drops of this solution, about 1 cm in diameter, are now placed on a sheet of freshly abraded steel when pink cathode areas and blue anode areas appear. 

If a compound has been recrystallised from petrol, benzene, etc.y some freshly cut shavings of clean paraffin wax should be added to the calcium chloride in (A) or to the sodium hydroxide in D, The surface of the wax absorbs organic solvent vapours (particularly the hydrocarbons) and the last trace of such solvents is thus readily removed from the recrystallised material. 

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