Convection flow coil

The microreactor system consists of a pumping module (R2+) and a four-channel heated component (R4). Two independently conducted flow streams are mixed in a T-piece and driven through a convection-flow coil (CFC, volume 10 ml) made of poly(fluoroacetate) (PFA). After the CFC, the flow is guided through Omnifit glass columns [41] packed with immobilized scavengers. 

In the initial trials, a library of alkynes was synthesized from various aldehydes (Scheme 17). On the exit of the convection-flow coil, the flow was guided through a series of resin-filled glass cartridges to remove the side products and the unreacted materials and to afford the end stream with sufficient purity (>95%). 

Baumann et al. [6] also utilized a commercially available flow reactor. The setup from Vapourtec (www.vapourtec.co.uk) exhibits HPLC pumps, sample loops containing a maximum of 2 ml substrate solution each, and the so-called convection flow coil (ID 1 mm, V=9ml) as residence time module (Figure 6.8). The procedure was similar to that of Seeberger et al. with superheated dichloromethane as solvent, the reactions were carried out at temperatures of 70-90 °C and 100 psi (6.9 bar). With an overall flow rate of 0.3 ml/min... 

The heat transfer coefficient at the inside wall and pressure drop through the coil can be estimated using the correlations for flow through pipes see Section 12.8 and Volume 1, Chapters 3 and 9. Correlations for forced convection in coiled pipes are also given in the Engineering Sciences Data Unit Design Guide, ESDU 78031 (2001). 

FIG. 27-51 Representative types of fired heaters a) vertical-tube cylindrical with cross-flow-convection section (h) horizontal-tube cabin (c) vertical cylindrical, helical coil, from Berman, Chem. Eng. 85 98-104, June 19, 1978.)... 

Figure 3-20. Vertical-tube-fired heaters con be identified by the vertical arrangement of the radiant-section coil, (a) Vertical- lindrical all radiant, (b) Vertical-cylindrical helical coil, (c) Vertical-cylindrical, with cross-flow-convection section. d) Vertical-cylindrical, with integral-convection section, (e) Arbor or wicket type, (f) Vertical-tube, single-row, double-fired. [From Chem. Eng, 100-101 (June 19, 1978).]...

Frequently, coil data will he available for a design air flow, hut the system resistance reduces this flow to a lower value. There is a double effect the lowering of the In MTD and the lower heat transfer from the coil by convection. 

The dispersion in geometrically deformed tubes (squeezed, twisted and coiled ) has been extensively studied by Halasz (6, 7 and 8), and the effect of radial convection (secondary flow) on the dispersion introduced in tightly... 

Convection is a mechanism of heat transfer wherein a flowing fluid, liquid or gas, acts as a heat sink or source to a solid object. An example of forced convection is where water, under pressure, moves through copper cooling coils to act as a heat... 

The convection heat transfer coefficient can also be increased by inducing pulsating flow by pulse generators, by inducing swirl by inserting a twisted tape into the tube, or by inducing secondary flows by coiling the tube. 

In forced convection, the fluid is moved over the surface by a pump or blower neglecting natural convection are usually neglected. The study of forced convection is of great practical importance and vast amount of data have been amassed for streamline and turbulent flow in pipes, across and parallel to tubes, across plane surfaces, and in other important configurations such as jackets and coils. 

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