Pilot scale reactor

Secondary circuit (feed) Primary circuit (feed) 

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One goal of catalyst designers is to constmct bench-scale reactors that allow determination of performance data truly indicative of performance in a full-scale commercial reactor. This has been accompHshed in a number of areas, but in general, larger pilot-scale reactors are preferred because they can be more fully instmmented and can provide better engineering data for ultimate scale-up. In reactor selection thought must be given to parameters such as space velocity, linear velocity, and the number of catalyst bodies per reactor diameter in order to properly model heat- and mass-transfer effects. 

Houcine, L, Plasari, E., David, R. and Villermaux, J., 1997. Influence of mixing characteristics on the quality and size of precipitated calcium oxalate in a pilot scale reactor. Transactions of the Institution of Chemical Engineers, 75, 252-256. 

Farley and Ray (F3) have reported holdup and conversion data for the Fischer-Tropsch process carried out in a pilot-scale reactor. 

Kolbel et al. (K16) examined the conversion of carbon monoxide and hydrogen to methane catalyzed by a nickel-magnesium oxide catalyst suspended in a paraffinic hydrocarbon, as well as the oxidation of carbon monoxide catalyzed by a manganese-cupric oxide catalyst suspended in a silicone oil. The results are interpreted in terms of the theoretical model referred to in Section IV,B, in which gas-liquid mass transfer and chemical reaction are assumed to be rate-determining process steps. Conversion data for technical and pilot-scale reactors are also presented. 

Example 1.7 Suppose a pilot-scale reactor behaves as a perfectly mixed... 

It is common practice to use geometric similarity in the scaleup of stirred tanks (but not tubular reactors). This means that the production-scale reactor will have the same shape as the pilot-scale reactor. All linear dimensions such as reactor diameter, impeller diameter, and liquid height will change by the same factor, Surface areas will scale as Now, what happens to tmix upon scaleup ... 

Polymerizations often give such high viscosities that laminar flow is inevitable. A t5rpical monomer diffusivity in a polymerizing mixture is 1.0 X 10 ° m/s (the diffusivity of the polymer will be much lower). A pilot-scale reactor might have a radius of 1 cm. What is the maximum value for the mean residence time before molecular diffusion becomes important What about a production-scale reactor with R= 10 cm ... 

Example 11.18 Consider a gas-sparged CSTR with reaction occurring only in the liquid phase. Suppose a pilot-scale reactor gives a satisfactory product. Propose a scaleup to a larger vessel. 

The general operation of the pilot scale reactor has be previously described by Pareek et. al. [3]. However, modifications were required to allow the injection of the gas and liquid tracers, and their subsequent detection at the outlets. The liquid tracer, 5mL Methyl blue solution (lOgL" ), was injected via a syringe inserted into the liquid feed line. Outlet samples were measured with a Shimadzu 1601 UV-Vis Spectrophotometer at a wavelength of 635nm. A pulse (20mL) of helium gas tracer was introduced using an automated control system, with the outlet concentration monitored in real-time with a thermal conductivity detector. Runs were carried out based on a two-level... 

We come to conclude that a pilot-scale reactor with capacity of ea. 120 L was necessary to produce 50 kg of GBL pa- one bateh. By assuming the compressed liquid ramditions, specific volume of total mixture was also calculated in order to compare with Ok result calculatoi on fire basis of saturated liquid conditions. However, total volume of mixture was not greatly change At the compressed liquid conditions, total volume of mixture was decmised only 6% (ximpared to that calculate at the saturated liquid conditions. 

Several pilot plants have been built to test periodic flow direction reversal. Pilot-scale reactors with bed diameters from 1.6 to 2.8 m were operated with flow reversal for several years. The units, described by Bunimovich et al. (1984,1990) and Matros and Bunimovich (1996), handled 600 to 3000 m3/h and operated with cycle periods of 15 to 20 min. Table VIII shows the performance of these plants for different feeds and potassium oxide promoted vanadia catalysts. The SVD catalyst was granular the IK-1-4 was in the form of 5 (i.d.) x 10-mm cylinders, while the SYS catalyst was... 

A mixture of the hydride and solvent was heated to, and held at 50°C. An exothermic reaction, which increased the temperature to 75°C, could not be controlled by external cooling, and the pilot-scale reactor contents erupted. It was later found that an exotherm began to develop at 26° (or at 40-50° with carefully dried solvent), and the subsequent reaction accelerated rapidly. Avoidance of holding mixtures hot is recommended, particularly when scaling up reactions. Similar behaviour was seen with dimethylacetamide [1], A further similar plant-scale incident was reported, with onset of the exotherm at 40°C, followed by self-heating to 100°C in 10 min, even with maximum cooling applied [2],... 

A pilot-scale reactor for the oxidation of o-xylene by air according to the following reaction has been constructed and its performance is being tested. 

Fig. 1 Pilot scale reactors for the aerobic treatment of pig slurry...

Sh. Agarwal, Ph. Cluxton, M. Kemper, D.D. Dionysiou, S.R. Al-Abed, Assessment of the functionality of a pilot-scale reactor and its potential for electrochemical degradation of calmagite, a sulfonated azo-dye, Chemosphere, 73, 837-843 (2008). 

Pilot-Scale Reactor. Anaerobic digester effluent was obtained from a non-mixed pilot-scale reactor system operated at Walt Disney World, Orlando, FL, and fed an RDF MSW/sludge blend (64). The MSW feedstock was obtained from Baltimore, MD, and the municipal sewage sludge from the Walt Disney World Complex. Fresh effluent samples were sealed under anaerobic conditions and shipped overnight in ice for analysis. 

Concerning the operation of catalysts under adiabatic conditions, Basini et al. [156] reported the results of methane partial oxidation runs in a pilot-scale reactor operating at high pressure and short contact times, showing stable activity (almost complete conversion of methane and over 90% selectivity to CO and H2) during more than 500 h on-stream. In addition, operability for 20 000 h bench-scale testing has been claimed recently by the same group [157]. 

Based on actual methane use in the pilot-scale reactor projected methane costs for a large unit were 0.33 per 1000 gal of water treated. This cost could be reduced by modifications to the system. Calculated theoretical minimum methane costs were 0.05 per 1000 gal (D10498D). 

Example 1.7 Suppose a pilot-scale reactor behaves as a perfectly mixed CSTR so that Equation (1.49) governs the conversion. Will the assumption of perfect mixing remain valid upon scaleup ... 

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