Reactor single tube

Figure 4.6 Typical temperature profile for a single tubular reactor (single tube length 10 m).

By this time, the construction of the production unit was underway, and in a great hurry a pilot-plant was constructed, the size of a single tube of the 4000 tube commercial reactor. Interestingly, when the glowing discharge... 

Figure 12.13. Sketch of Dinex electrochemically promoted reactor constructed from single tubes.18 20 Reprinted with permission from the Society of Automotive Engineers.

Make the tube longer. Adding tube length is not a common means of increasing capacity, but it is used. Single-tube reactors exist that are several miles long. 

The Reynolds number is constant when scaling in parallel, but it increases for the other forms of scaleup. When the large and small reactors both consist of a single tube. 

CSTRs, shell-and-tube reactors, and single-tube reactors, particularly a single adiabatic tube. Realistically, these different reactors may all scale similarly e.g., as but the dollar premultipliers will be different, with CSTRs being more expensive than sheU-and-tube reactors, which are more expensive than adiabatic single tubes. However, in what follows, the same capital cost will be used for all reactor types in order to emphasize inherent kinetic differences. This will bias the results toward CSTRs and toward shell-and-tube reactors over most single-tube designs. 

What is needed at this point is a correlation or other means for estimating r] at every point in the reactor. This may be done empirically for example, by running a single tube of what ultimately will be a multitubular reactor. However, some progress has been made in determining r] from first principles. We outline the salient results achieved to date. 

All conventional reactors, tested before using the micro reactor (simply since micro reactors were hardly available at that time), only fulfilled the demands of one measure, at the expense of the other measures. For instance, a single-tube reactor can be operated nearly isothermally, but the performance of the oxidative dehydrogenation suffers from a too long residence time. A short shell-and-tube reactor provides much shorter residence times at improved heat transfer, which however is still not as good as in the micro reactor. 

To exploit the numerous applications for floating catalyst VGCF in engineered plastics, production rates are projected to be on the order of several pounds per hour from a single tube reactor. Demonstration experiments on a small scale have shown feasibility of accomplishing the desired rate of production. Economic production of such quantities will involve recapture of energy in the heated unreacted gas which exits the reactor, as well as automated collection, debulking, and preform fabrication systems. 

The actual configuration of the reactor may take various forms depending on the precise requirements of the process. For example, for a high-temperature homogeneous gas-phase reaction such as naphtha cracking, the reactor may be simply a long tube in a furnace [Fig. 6(a)]. In other cases, the single tube is replaced by a number of tubes in parallel as shown in Fig. 6(b). 

Figure 7-3 Packed bed reactors, which may be a single bed, many tubes, or a single tube filled...

Note the different ds in these problems. While d always signifies diameter, D is reactor diameter (or diameter of a cylinder or sphere because that notation is used in mass transfer rather than the radius R), dp is the diameter of a single pore, and d is the diameter of a single tube in a tube waU reactor. 

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