Rotating drum reactor

The influence of eutectic media on the kinetics and productivity of biocatalysts has yet to be fully elucidated. Syntheses in eutectic suspensions have been scaled up to the pilot scale in a rotating drum reactor. The bioactive peptide Na-Cbz-L-Lys(Ne-Cbz)-Gly-L-Asp(OAll)-L-Glu(OAll)OEt was synthesized via a sequential N-to-C strategy in a heterogeneous solid-liquid mixture of the substrates in the presence of chymopapain and subtilisin as well as 16-20% (w/w) water and ethanol (Gill, 2002). At substrate concentrations of around 1 m, yields of 67-74% per step at product concentrations of 0.36, 0.49, and 0.48 kg kg-1 were achieved. The corresponding space-time yields were between 0.30 and 0.64 kg (kg d)-1 and biocatalyst reuse provided productivities of 166-312 kg product (kg enzyme)-1. 

Compared with the rotating-drum reactor, the stirred-tank reactor is easy to operate, and the aggregation of substrate to form particles can be avoided. Because the substrate is quite wet, the energy consumption for agitation is generally high added to which the stirred tank reactor is hard to isolate completely from the environment and, therefore, contamination may occur. 

A. Toyoda, L. Zhang, T. Kanki, N. Sano, Degradation of phenol in aqueous solution by Ti02 photocatalyst coated rotating-drum reactor (SC) , Journal of Chemical Engineering of Japan, 33, 188-191, (2000). 

In batch SSP processes, crystallized PE pellets are loaded into rotating drum reactors heated to the required temperature under dry N2, and subjected to extremely low... 

Multiphase reaction engineering has developed into a very active field of research, with international symposia held at frequent intervals. We have only considered a few common reactor types currently in use. A few others of potential importance in relatively large volume intermediates production are the gas-liquid-solid fluidized beds, liquid entrained reactors, and rotating drum reactors. 

Several types of cementation reactor have been developed including ones employing hydraulic agitation, rotating-drum reactors, oscillating chamber reactors, and fluidized beds. 

Laboratory reactors for studying gas-liquid processes can be classified as (1) reactors for which the hydrodynamics is well known or can easily be determined, i.e. reactors for which the interfacial area, a, and mass-transfer coefficients, ki and kc, are known (e.g. the laminar jet reactor, wetted wall-column, and rotating drum, see Fig. 5.4-21), and (2) those with a well-defined interfacial area and ill-determined hydrodynamics (e.g. the stirred-cell reactor, see Fig. 5.4-22). Reactors of these two types can be successfully used for studying intrinsic kinetics of gas-liquid processes. They can also be used for studying liquid-liquid and liquid-solid processes. 

Mixed liquor from a municipal WW treatment plant Acid orange 8 Acid orange 10 Acid red 14 Rotating drum biofilm reactor Continuous Aerobic B Drum 22 7... 

Fig. 2 Sketch of some reactor typologies used in azo-dye conversion, (a) rotating biological contactor (b) drum reactor (c) fixed bed reactor (d) fluidized bed (e) UASB (f) airlift...

Table 1 reports a wide spectrum of typologies of biofilm reactor upflow anaerobic sludge bed (UASB), fluidized bed, airlift, fixed bed with and without recycle, mechanically agitated vessel, rotating drum and rotating biological contactor. Each reactor is characterized by positive features and drawbacks. 

The horizontal reactor of the rotating drum type (Fig.8) does not have certain drawbacks characteristic of the vertical reactor. Particularly, rotating drums provide for a more thorough mixing of gaseous chlorine derivative with contact mass, because they increase the time of contact between the phases (10 times in comparison with the fluidised layer) consequently, the degree of chlorine derivative also grows. In the production of phenyl-chlorosilanes they create favourable conditions to increase the yield of di-phenyldichlorosilane. 

Characteristics Reactor with fluidised layer Rotating drum with agitator (diameter 1600 mm)... 

The comparison of average and maximal heat intensities shows that a 400 mm reactor and a rotating drum operate in extreme heat modes, whereas a 600 mm reactor, taking into consideration the conditions of heat removal, gives an opportunity to increase the efficiency by 60%. 

Until now, bioreactors of various types have been developed. These include loop-fluidized bed [14], spin filter, continuously stirred turbine, hollow fiber, stirred tank, airlift, rotating drum, and photo bioreactors [1]. Bioreactor modifications include the substitution of a marine impeller in place of a flat-bladed turbine, and the use of a single, large, flat paddle or blade, and a newly designed membrane stirrer for bubble-free aeration [13, 15-18]. Kim et al. [19] developed a hybrid reactor with a cell-lift impeller and a sintered stainless steel sparger for Thalictrum rugosum cell cultures, and cell densities of up to 31 g L1 were obtained by perfusion without any problems with mixing or loss of cell viability the specific berberine productivity was comparable to that in shake flasks. Su and Humphrey [20] conducted a perfusion cultivation in a stirred tank bio-... 

As described previously pyrolysis is a process that thermally degrades organic waste at high temperatures in absence of air and oxygen. This process can be carried out in a rotary kiln reactor or in a fluidized bed. In a rotary kiln process the feed material is conveyed through a rotating drum (i.e. reactor) and is then pyrolysed in the hot atmosphere into gas and solid residues. The residence time of the reaction is dependent on the rotating... 

For certain industrial applications, a biofllm reactor is preferred. In one type a rotating drum becomes coated with the waste stream as it moves through a tank of the wastes. As the drum surface moves from below the liquid level to above, the attached wet film becomes exposed to air (see Fig. 1C). Alternately, the waste liquid stream can be poured onto a bed of... 

Figure 14-5. Schematic representation of Figure 14-4. Schematic representation of corona reactor with a rotating drum on corona reactor. which the substrate is placed.

Rotary drum reactor with longitudinal fins [162]. Physical absorption in a noncoalescing material system (0.6 N sodium sulfite solution with 3 mmol CUSO4) was followed with measurements in a horizontal drum [D = 29 cm L/D w 1 8 longitudinal fins D/10). The liquid fraction made up 2.4-14.2% of the volume, the rotational speed was 0.5-10 min , the air throughput gc = 240 1/h. In several experiments a slurry was utilized, which was realized by adding 0-40 vol.-% of silica (80 pm, p = 2.65 g/1). It was found that ... 

The kinetic parameter can be estimated in laboratory reactors. For solid-fluid systems, this subject was described in Section 11.3.1.6. For fluid-fluid reactions, the commonly employed laboratory reactors include stirred cell, wetted wall column, rotating drum, laminar jet, stirred contractor, and others. These are schematically shown in Figure 11.14. In practically all of these reactors, the value of the fluid-fluid interfacial area is known. These reactors have been described by Treybal (1980) and Doraiswamy and Sharma (1984). As an illustration, the stirred cell will be described first, followed by a comparison with other laboratory reactors. The discussion of the stirred cell is restricted to gas-liquid systems, but it is also applicable (with minor variations) to liquid-liquid systems. 

In addition to the stirred cell, other laboratory reactors commonly used include rotating drum contactor, wetted wall column, wetted sphere column, laminar jet, and stirred contactor. These equipments are shown schematically in Figures 11.14b-f. AU have several common features, the principal one being a weU defined gas-liquid interfacial area and the ability to vary the area per unit reactor volume a). In the stirred cell, it is achieved by varying the liquid height. As an alternative way, a solid circular baffle is placed at the gas-liquid interface. Holes are drilled on the baffle plate so that the hole opening area becomes the interfacial area. For varying a, baffle plates are made with different free (hole) areas. 

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