Turbines types

The two procedures primarily used for continuous nitration are the semicontinuous method developed by Bofors-Nobel Chematur of Sweden and the continuous method of Hercules Powder Co. in the United States. The latter process, which uses a multiple cascade system for nitration and a continuous wringing operation, increases safety, reduces the personnel involved, provides a substantial reduction in pollutants, and increases the uniformity of the product. The cellulose is automatically and continuously fed into the first of a series of pots at a controlled rate. It falls into the slurry of acid and nitrocellulose and is submerged immediately by a turbine-type agitator. The acid is deflvered to the pots from tanks at a rate controlled by appropriate instmmentation based on the desired acid to cellulose ratio. The slurry flows successively by gravity from the first to the last of the nitration vessels through under- and overflow weirs to ensure adequate retention time during nitration. The overflow from the last pot is fully nitrated cellulose. 

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). 

Mechanical Cake Removal. This method is used in the American version of the dynamic filter described under cross-flow filtration with rotating elements, where turbine-type rotors are used to limit the cake thickness at low speeds. The Exxflow filter, introduced in the United Kingdom, is described in more detail under cross-flow filtration in porous pipes. It uses, among other means, a roUer cleaning system which periodically roUs over a curtain of flexible pipes and dislodges any cake on the inside of the pipes. The cake is then flushed out of the curtain by the internal flow. 

The American version of the dynamic filter, known as the Artisan continuous filter (Fig. 30), uses such nonfiltering rotors in the form of turbine-type elements. The cylindrical vessel is divided into a series of disk-type compartments, each housing one rotor, and the stationary surfaces are covered with filter cloth. The feed is pumped in at one end of the vessel, forced to pass through the compartments in series, and discharged as a thick paste at the other end. At low rotor speeds the cake thickness is controlled by the clearance between the scraper and the filter medium on the stationary plate, while at higher speeds part of the cake is swept away and only a thin layer remains and acts as the actual medium. 

A wide variety of turbine types and arrangements are used in modem power plants. For example, some smaH industrial plants may use only a single condensing turbine. Prepackaged steam/turbine generator systems can be economical for small-to-midsize instaHations. 

Fig. 9. Turbine-type pumps, (a) Deep-well wet. Courtesy of Goulds Pumps, Inc. (b) Caimed version.

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). 

Rotating electrical machines Specific requirements for turbine type synchronous machines BS EN 60034-3/1996 ... 

Rotating electrical machines Specific requirements for turbine type synchronous machines Specification for voltage regulation and parallel operation of a.c. synchronous generators — BS F.N 60034-3/1996 BS 4999-140/1987... 

The majority of centrifugal pumps have performance curves with the aforementioned profiles. Of course, special design pumps have curves with variations. Eor example, positive displacement pumps, multi-stage pumps, regenerative turbine type pumps, and pumps with a high specific speed (Ns) fall outside the norm. But you ll find that the standard pump curve profiles are applicable to about 95% of all pumps in the majority of industrial plants. The important thing is to become familiar with pump curves and know how to interpret the information. 

Figure 2-12. Efficiency of various expansion turbine types as a function of specific speed,...

Unit Design MW Turbine Type Efficiency at Design Output Point... 

Exhauster and Motor Air movers for LVHV systems are not conventional fans. The low static pressures needed to operate LVHV systems can be generated by multiple-stage centrifugal (turbine-type) exhausters. These utilize high-precision rotating blades that can be damaged by dust. Consequently, it is always necessary to have an air cleaner in an LVHV dust control system to protect the fan. The low static pressures also require air volume flow rates to be corrected to standard conditions for exhauster selection. 

Turbine type (a) offers t ery high heads at low flows, (b) self-priming, (c) limited to very clean, non-abrasive fluids with limited physical properUes, (d) clearances can be problem on assembly and maintenance. 

Figure 3-33. Performance of turbine type centrifugal pump. (Courtesy Roy E. Roth Co.)...

Mud motor Usually a positive displacement or turbine-type motor. 

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 performance, 178 Vertical in-line, 165, 175 Vertical multistage, 168 Vertical propeller, 169 Viscosity correction, 203-207 Pumps classes, 161... 

NPN is used as a rocket monoproplnt, a jet motor starting fuel its hot combustn prod gases are used to drive turbine type motors (Ref 4). 

The turbine type of helicity in canals is a toroidal turbine, and can occur with proper rotation axes and with 2V 42, 63 screw axes, and depends on the object rotated. It is necessary that a distinctive principal plane or axis of the host molecule or molecular fragment be canted in the cylindrical surface of the canal so that it is neither parallel to or perpendicular to the axis of the canal. No unequivocal instance of this type of helical canal has been reported. The cyclodextrin unimolecular hosts 3 4) might be... 

A turbine type agitator is commonly used for liquid-solid systems. Mixing rates depend on the forces required to suspend all solid particles. Minimum levels can be determined for (1) lifting the particles, and (2) for suspending them in an homogeneous manner [200]. Similar requirements apply to liquid-liquid systems. For cases where two poorly miscible fluids of about equal volume are used in the reaction, the mixer is placed at the interface. For a bench-scale experimental system of about 2 liters capacity, the minimum rotational speed to obtain well-dispersed system is 300 to 400 rpm [201], depending on the type of mixer. This rotational value decreases as the vessel volume increases. 

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

The turbine technology is represented by five different turbine types in the simulation covering turbines between 500 kW and 4.5 MW. The highest shares have 1.5 and... 

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... 

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