Impeller turbine-type

The Oldshue-Rushton column (Eig. 15d) was developed (162) in the early 1950s and has been widely used in the chemical industry. It consists essentially of a number of compartments separated by horizontal stator-ring baffles, each fitted with vertical baffles and a turbine-type impeller mounted on a central shaft. Columns up to 2.74 m in diameter have been reported in service (162—167). Scale-up is reported to be reliably predictable (168) although only limited performance data are available (169). A detailed description and review of design criteria are available (170). 

Equipment suitable for reactions between hquids is represented in Fig. 23-37. Almost invariably, one of the phases is aqueous with reactants distributed between phases for instance, NaOH in water at the start and an ester in the organic phase. Such reac tions can be carried out in any kind of equipment that is suitable for physical extraction, including mixer-settlers and towers of various kinds-, empty or packed, still or agitated, either phase dispersed, provided that adequate heat transfer can be incorporated. Mechanically agitated tanks are favored because the interfacial area can be made large, as much as 100 times that of spray towers, for instance. Power requirements for L/L mixing are normally about 5 hp/1,000 gal and tip speeds of turbine-type impellers are 4.6 to 6.1 i7i/s (15 to 20 ft/s). 

Milk-of-lime transfer pumps should be of the open impeller centrifugal type. Pumps having an iron body and impeller with bronze trim are suitable for this purpose. Rubber-lined pumps with rubber-covered impellers are also frequently used. Makeup tanks are usually provided ahead of centrifugal pumps to ensure a flooded suction at all times. Plating out of lime is minimized by the use of soft water in the makeup tank and slurry recirculation. Turbine pumps and eductors should be avoided in transferring milk of lime because of scaling problems. 

Calculate mass transfer coefficient in a 60 m3 fermenter with a gas and liquid interfacial area of a = 0.3 m2-m 3, given pbroth = 1200kg m-3. The small reactor has working volume of 0.18m3, 1 vvm aeration rate. Oxygen transfer rate (OTR) is 0.25kmol in 3 h 3. There are two sets of impellers, and flat-blade turbine types of impeller were used, HL= 1.2/),. Find the exact specifications of a large fermenter. 

Turbine type impellers, 16 699 Turbo expanders, in cryogenic processes, 13 698... 

Vertical shaft, turbine type pumps have their impellers submerged, hence, they are ideal for conditions where a suction lift would be required for horizontal pumps. The second impeller from the bottom of the pump bowl assembly should be submerged below the lowest pumping water level. The submergence should be increased by 1 ft (0.30 m) for every 1,000 ft (305 m) of elevation above sea level. These pumps should provide 150% of the rated capacity... 

Experimental apparatus and procedure. Figure 1 is a schematic diagram of the experimental apparatus. The crystallizer was a 1 liter stirred tank reactor made of acrylic resin and is considered to be a continuous MSMPR reactor. The reactor was 0.1m in diameter and the liquid height 0.14m. The impeller used was of the 6-blade turbine type and operated at 450 rpm to... 

The agitation was accomplished with the turbine-type mixer and the largest axial impeller was 40.64 cm. The pilot batch was mixed at 90rpm (1.5/sec). From the initially known data, the D/T ratio was determined. 

Now the appropriate shaft speed for scaled-up production equipment can be calculated. The tank used for production batches has a capacity of 3780 L. It is equipped with a turbine-type agitator that has a shaft speed range of 20 58 rpm. The diameter of this tank is 167 cm. The diameter of the largest axial impeller is 87 cm. Given the diameter of the production tank, the cross-sectional area can be determined as... 

Estimate the stirrer power requirement P for a tank fermentor, 1.8 m in diameter, containing a viscous non-Newtonian broth, of which the consistency index A = 124, flow behavior index n = 0.537, density p = 1050 kg m", stirred by a pitched-blade, turbine-type impeller of diameter d = 0.6 m, with a rotational speed AT of 1 s . ... 

High-pressure autoclaves are also available from Parr Instrument Co. stirring is by turbine-type impellers. The reaction vessel is provided with a liquidsampling valve which enables monitoring procedures. Both manufacturers provide detailed operating and servicing advice. 

Extractor 10 Back pressure regulator 15 Stirrer (Turbine type impeller)... 

Stirred vessel Figure 2.5(a) (Cylindrical flat bottom vessel, four baffles). Impeller six-flat blade turbine type. 

Recently, in contrast to the traditional small impellers, a large impeller has been manufactured in Japan. In general, it has been said that the disc turbine-type, turbine-type, and pitched-type impellers mainly produce radial, tangential,... 

Loiseau et al. (1977) found that their data for nonfoaming systems agreed well with Eq. (3.3). Calderbank (1958), Hassan and Robinson (1977), and Luong and Volesky (1979) have also proposed correlations for power consumption in gas-liquid systems. Nagata (1975) suggested that power consumption for agitated slurries can be reasonably predicted from these correlations by the correction factor psi/pL, where psl is the density of the slurry. Power consumption for a gas-liquid-solid system has also been studied by Wiedmann et al. (1980). They examined the influence of gas velocity, solid loading, type of stirrer, and position of the stirrer blades on power consumption plots of power numbers vs. Reynolds numbers for propeller and turbine type impellers proposed by them are shown in Fig. 13. 

Mechanically agitated reactors have been used for cultivation of plant cells (Kato et al., 1972 Tanaka, 1981). Ajar fermenter with a six fiat-blade turbine and a modified paddle has been used by Tanaka (1981) and a similar jar fermenter with two disk turbine impellers has been used by Kato et al. (1972) at about 50 rpm with no significant shear damage to plant cells. Paddle-type impellers were found to be more appropriate (less shear damage) than flat-blade turbine type impellers (Kato et al., 1972). The only production-scale reactor used for shikonin production in Japan is also an agitated vessel. 

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