Centrifugal pumps turbine drives

The study of cavitation in cryogenic fluids and various hydrocarbons is being applied to research in centrifugal pumps, turbines, marine propellers, etc. The method of applying this to pumps is shown in the enclosed Figure 15, in which sensing strips are mounted on the pump rotor and connected through electrical leads to a miniaturized electronic control circuit located in the hollow pump drive shaft. The output of this circuit is used to vary the frequency of an F-M oscillator. The... 

The primaiy advantages of a centrifugal pump are simplicity, low first cost, uniform (nonpulsating) flow, smaU floor space, low maintenance expense, quiet operation, and adaptability for use with a motor or a turbine drive. 

There are two general types of steam turbines extraction and condensing. The most common turbine with which the process operator comes into contact is used to spare an electric-motor-driven centrifugal pump. The three-phase, AC motors used in the United States and South America are either 1800 or 3600 rpm. The motors used in Europe are 1500 or 3000 rpm. Small steam turbines (20 to 500 hp) used to drive centrifugal pumps, are rated for the same speed as the electric motors that are used in that particular service. 

Power pumps typically have high efficiency and are capable of developing very high pressures. Either electric motors or turbines can drive them. They are relatively expensive pumps and can rarely be justified on the basis of efficiency over centrifugal pumps. However, they are firequently justified over steam reciprocating pumps where continuous duty service is needed due to the high steam requirements of direct acting steam pumps. 

The fuel. skid. This could contain a gas compressor if the fuel gas pressure is low and a knockout drum for any liquid contamination that the gas may have. The requirement of fuel gas pressure is that it should be operated at a minimum of 50-70 psi (3.5-4.83 Bar) above the compressor discharge pressure. The compressor and its motor drive fall under the drive level hierarchy. In the case of liquid fuels, the skid may also contain a fuel treatment plant, which would have centrifuges, electrostatic precipitators, fuel additive pumps, and other equipment. These could be directly controlled by the D-CS system, which would then report its readiness to the gas turbine controller. 

A steam turbine is a machine with an ancient genealogy. It is a direct descendant of the overshot water wheel, used to kick off the industrial revolution in England, and the windmill still used in Portugal. Turbines are widely used in process plants to drive everything from 2-hp pumps to 20,000-hp centrifugal compressors. They are versatile machines, in that they are intrinsically variable-speed devices. Electric motors are intrinsically fixed-speed machines. It is true that there are a variety of ways to convert AC (alternating-current) motors to variable speed, but they are all expensive and complex. 

Turbines are a common feature on process plant, where they provide economical drives for rotating machinery, particularly centrifugal and axial pumps and compressors, as well as electrical generators in power stations. They use the expansion of hot, high-pressure gas or steam to produce mechanical power. 

Gas turbine Seleaion of gas turbines, like any other drive system, is based on economics. The availability of gas in such remote areas as deserts and offshore platforms makes it a prime source of power in these locations. Gas turbines are used in various applications, including gas transmission, gas lift, liquid pumping, gas reinjection, and process compressors. Air is compressed in the gas turbine by the centrifugal compressor and is discharged into a reverse flow annular combuster in which fuel is injected through nozzles. The transition dua directs tfie hot gas into a gas gener-... 

Surface condensers are used in conjunction with condensing steam turbines that drive large centrifugal compressors. As depicted in Exhibit 4-25 the exhaust steam enters the top of the condenser and passes through the shell, which is filled with tubes. Cold water is pumped through the tubes while hot exhaust steam passes around the outside. Hot water, called condensate, results and collects in the hot well at the bottom of die condenser. 

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