Turbine drives

The hot gases from the combustor, temperature controlled to 980°C by excess air, are expanded through the gas turbine, driving the air compressor and generating electricity. Sensible heat in the gas turbine exhaust is recovered in a waste heat boiler by generating steam for additional electrical power production. 

The laboratory tubular centrifuge is similar to the industrial model. It operates with a motor or turbine drive at speeds to 50,000 rpm, generating 65,000 G at the latter speed in the 4.5 cm diameter bowl. The nominal capacity range is 30—2400 cm /min. This centrifuge is uniquely capable of separating far finer particles than any other production centrifugation equipment except the botde centrifuge. It is widely used in the production of flu vims. 

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. 

Right-angle gear drive is preferred for fans over 3 m (10 ft) in diameter, for electric motors over 22.4 kW (30 hp), and with steam-turbine drives. 

The turboprop engine has a power turbine instead of the nozzle as seen in Figure 4-2. The power turbine drives the propeller. The unit shown schematically is a two-shaft unit, this enables the speed of the propeller to be better controlled, as the gasifier turbine can then operate at a nearly constant speed. Similar engines are used in helicopter drive applications and many have axial flow compressors with a last stage as a centrifugal compressor as shown in Figure 1-14. 

The system should have an aeeumulator to maintain suffieient oil pressure while the standby pump aeeelerates from an idle eondition. An aeeumulator beeomes a must if a steam turbine drives the standby pump. Overhead tanks are speeified by many users to assure flow to eritieal maehinery eomponents. The sizing of the tanks varies depending on the applieation. In some gas turbine applieations, the bearings reaeh maximum temperature as long as 20 minutes after shutdown. 

With large power installations of 40 to 50 thousand horsepower compressing flammable gases, this is not usually possible, and each individual item has to be separately tested. A typical situation could be a 40 thousand horsepower gas turbine driving multibody process gas compressors, where the engineering and manufacture involve one contractor and six sub-contractors located in the UK, U.S.A., Japan, and Indonesia. The difficulties of separately testing each sub-unit to ensure compatibility will be compounded by distance and culture. 

If HjS is continuously present in the flare gas or if the flare seal drum also functions as a sour water disengaging drum, then the effluent seal water must be routed to a sour water stripper, desalter, or other safe means of disposal. Withdrawal from the drum is by pump in place of the normal loop seal arrangement. Two pumps are provided one motor driven for normal use, and the other having a steam turbine drive with low pressure cut-in. The seal drum level is controlled by LIC with high and low alarm lights plus an independent high level alarm. 

The Joule-Brayton (JB) constant pressure closed cycle is the basis of the cyclic gas turbine power plant, with steady flow of air (or gas) through a compressor, heater, turbine, cooler within a closed circuit (Fig. 1.4). The turbine drives the compressor and a generator delivering the electrical power, heat is supplied at a constant pressure and is also rejected at constant pressure. The temperature-entropy diagram for this cycle is also... 

Turbine drive easily adapted to waste-heat recovery for high fuel efficiency. 

Turbine drives have higher fuel rate than reciprocating units. 

When the actual maximum gear box horsepower is known from the manufacturer, it should be used as long as it is equal to or greater than the 5% allowance noted above. The impeller/fluid horsepower allowable variation should still be 10% or greater. For example, if the calculated required motor drive (or turbine drive) hp = 23, (i.e., 19.55/0.85), the next standard motor is 25 hp, so use this, never less than the 23 indicated above because 23 hp is non-standard, and no such motor hp exists. 

A surface condenser condensing the steam from a process turbine drive operates at 1.0 in. Hg abs. The condensing load is 85,000 Ibs/hr steam. WTat is the capacity of the ejector ... 

The evaluation of steam turbine drives versus electric motor selections for an application is reviewed by Ranade, et al. ... 

The turbine applied to driving mechanical equipment is not operated (very often) with extraction or bleed streams. Here again, this depends upon the plant steam balance, and this is one of the fine features of steam turbine drive. The flexibility of design and application allow it to be set in the proper place for the economic balance of a system. The decision as to condensing or noncondensing should not be... 

Figure 15.37 A single-stage steam turbine driving an alternator...

A turbine drive is preferred where it helps balance the energy system of a plant or where the steam or gas can be... 

ASME recommends that for Industrial WT, high-duty, primary-fuel-fired, turbine drive boilers, where local heat fluxes are greater than 1.5 x 105 Btu/hr/ft2 (> 473.2 kW/m2), use values for at least the next highest pressure range. 

Table 12.2 (ASME Consensus table 1) Suggested water chemistry limits. Industrial watertube, high duty, primary fuel fired, drum type Makeup water percentage Up to 100% of feedwater. Conditions Includes superheater, turbine drives or process restriction on steam purity Saturated steam purity target See tabulated values below... 

Conditions No superheater, turbine drives, or process restriction on steam purity Steam purity (7) 1.0 ppm (mg/1) TDS maximum... 

Conditions No superheater, turbine drives, or process restriction on steam purity... 

Note in practice superheated steam would probably be generated, for use in a turbine driving the air compressor. 

If a steam turbine generates electricity, then the flow through the turbine can be varied within the minimum and maximum flows allowed by the machine. If a steam turbine is connected directly to a drive (e.g. a back-pressure turbine driving a large pump), then there is likely to be no flexibility to change the flowrate through the steam turbine as this is fixed by the power requirements of the process machine. 

In 1992, Volvo built an aluminum-bodied hybrid Environmental Concept Car (ECC) to California emission mandates. It had the recyclable plastic panels and water-based paints that are used by Volvo. A series hybrid drive train was used where a diesel gas turbine drives a generator to charge a battery pack to power an electric motor. The system is complex, but the car achieves good performance with low emissions and a 400-mile range. 

A031 Pump Item Number Turbine Drive ITEM NO T c 24... 

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