Coiled reactors

But when the neutral is grounded through an arc-suppression coil (reactor) the current through the grounded neutral may be of a limited amplitude, say, up to its continuous rating (Section 20.5) and it may exist for longer. 

The maximum rate of polymerization has been confirmed to occur at the laminar-turbulent flow transition. The rate of polymerization was observed to be maximum at the transition for both straight reactors as well as for the helically-coiled reactor for which the transition is at a Reynolds number higher than that of the straight tube. The helically coiled tubular reactor is of industrial interest since it is much more compact and, consequently, the cost and the temperature control problems are more tractable. 

It is noted that the maximum value of rp in the helically coiled reactor is larger than the maximum observed in the straight tube reactor. The rp increases with increasing Reynolds number while the molecular weight (at a given conversion) decreases. 

This very large length of more than 2 km, or about 1 mile and a quarter, can be divided into n connected tubes, each with a length of 2036.36/n m. In this case each tube section has the volumetric flow rate c/(per tube) = 0.003/n m3/(sec tube) and the number n can be 100 or 1000, for example, depending on the mechanical and locational factors. Alternatively the total length L = 2036 m can be achieved by a coiled reactor. The particular choice of apparatus is based on mechanical engineering factors. 

Dow and Monsanto, among others, have investigated the manufacture of SMA resins both with and without rubber modification. Moore at Dow Chemical Company described a method of producing SMA copolymers via a recirculated coil reactor [74]. 

Analysis obtained by mass spectrometry. The above sample of pyrolysis product was obtained at 835°F, 300 psig, in a continuous-flow coil reactor, residence time 45 min. 

The pipe coil reactor is made of Inconel 625, 15 metres in length with an inner diameter (i.d.) of 8 mm and an outer diameter (o.d.) of 14.4 mm. It is submerged in a fluidised sand bath, which is electrically heated and acts as a thermostat. 

Heavy Oil Preparation and Separation. Hydrogenation of Hiawatha, Utah, coal [C 72.0 H 5.6 N 1.7 S 0.90 O 19.8 dry, ash-free (DAF) %] was performed at a reaction temperature of 510°C and 12.4-MPa hydrogen pressure with ZnCl2 impregnated on the coal as catalyst in an entrained-flow, tubular coil reactor (10). The reaction products were trapped in three reservoirs connected to the reactor in series and were separated according to their condensability. Heavy-oil products collected in the first reservoir, nearest to the reactor, were used in this study. 

Singh, J. P. and Ghaly, A. E. (2006). Reduced fouling and enhanced microbial inactivation during online sterilisation of cheese whey using a UV coil reactor. Bioprocess Biosyst. Eng. 24, 269-281. 

Contactors in which gas is dispersed into the liquid phase Plate columns (including control cycle reactors) Mechanically agitated reactors (principally stirred tanks) Bubble columns Packed bubble columns Sectionalized bubble columns Two-phase horizontal contactors Cocurrent pipeline reactors Coiled reactors Plunging jet reactors, ejectors Vortex reactors... 

Serpentine geometry enhances the radial mixing better than the helically coiled reactors even at low flow rates... 

Sensitivity Analysis of Length-to-Diameter Ratio for the Helical Coil Reactor... 

FIGURE 1.1 The flow analyser. The figure represents a flow system involving only three streams sample (S), carrier/wash (C) and reagent (R). Rc and D specify the coiled reactor and the flow-through detector. 

FIGURE 2.4 Flow diagram of a single-channel segmented flow analyser and the associated recorder tracing. S/C — sample/carrier wash stream Air = air R = reagent R( = coiled reactor DB — de-bubbler D = detector arrows = sites where pumping is applied. 

The flow pattern is also modified when reactors other than straight open tubes are used. In coiled reactors, all fluid elements cannot be displaced on parallel trajectories, as the distances travelled are dependent on their relative positions. This results in split circulation of the fluid elements (Fig. 3.5), which is a consequence of the establishment of secondary flows [48]. The effect becomes more pronounced at higher flow rates. Its beneficial influence on mixing conditions, hence, on sample broadening and sampling rate, has often been emphasised [10,49]. An analogous but more pronounced effect is observed with knitted (or 3-D) reactors [50]. 

FIGURE 4.13 Schlieren signals recorded for different solutions with the same refractive index. Carrier stream = water coiled reactor length = 100 cm a. b, c, d = 2.0 mol L-1 HC1,11.2% (m/v) sucrose, 14% (m/v) glycerol, and 24.13% (m/v) ethanol respectively. Other conditions are as in Fig. 4.13. Reprinted from Anal. Chim. Acta 234 (1990) 153, E.A.G. Zagatto, M.A.Z. Arruda, A.O. Jacintho, I.L. Mattos, Compensation of the Schlieren effect in flow-injection analysis by using dual-wavelength spectrophotometry, with permission from Elsevier (Ref [28]). 

FIGURE 5.2 Flow pattern inherent to segmented flow analysis. 1 = tube wall of part of a coiled reactor 2 = thin liquid layer adhering to it 3 = vortices inside the liquid phase 4 = air bubble outer large arrow = overall displacement of the segmented flow. Adapted from P.J. Worsfold, A. Townshend, C.F. Poole (Eds), Encyclopedia of Analytical Science, 2nd Edn, Oxford, 2005, v.3, p.24, E.A.G. Zagatto, PJ. Worsfold, Flow Analysis Overview, with permission from Elsevier (Ref. [4]). 

Proteins 0.08 mol IA1 Na2S04, pH 7 0.26-1.05 Spectrophotometry 10-m coiled reactor (Teflon tubing, 0.5 mm i.d., 1 cm winding diameter) immersed into a 20°C thermostatic water bath. [70]... 

The type of tubing used for constructing the manifold should always be specified but less emphasis should be given to manifold components outside of the analytical path. There are different types of reactor (see 6.2.3) and they should be specified. The coiled reactor is by far the most common, and no further information means that this kind of reactor is used. Length and inner diameter of the tubing, winding diameter of the coiled reactor and the presence of different accessories (mixing chambers, solid-phase mini-columns, immobilised enzymes and connectors) in the analytical path should be reported. 

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