Steam turbines condensing

The calculations for the steam-turbine condenser can only be performed if the steam condensate flowrate is known. This... 

In the 1950s Hickman developed a centrifugal vapor compression evaporator for seawater desalination (53). This device consisted of multiple spinning discs. Seawater sprayed on one side of the disc evaporated, while the centrifugal force removed the residue from the plate surface. The vapor was compressed and returned to the opposite side of the plate, where condensation provided the heat for evaporation and the desired freshwater for recovery. Overall heat transfer coefficients of 18 kW/m2-K are about three times higher than those achieved in steam turbine condensers. 

D. W. Nobbs and Y. R. Mayhew, Effect of Downward Vapor Velocity and Inundation on Condensation Rates on Horizontal Tube Banks, Steam Turbine Condensers, National Engineering Laboratory Report No. 619, East Kilbride, Glasgow, pp. 39-52,1976. 

Steam turbines (condensing) Shaft power, P, Hp 250-10,000 Hp C, = 20,000/ Carbon steel... 

Maximise condensate recovery from various points in the plant—specifically from steam turbine condenser and process units (in cogeneration plants). 

Calculate the steam prices based on enthalpy-based method for the steam system in Figure 17.1, which consists of major components of a complex steam system boilers with deaeration and makeup, back-pressure steam turbine, condensing turbine, process steam demand, steam letdown vale, desuperheater, and so on. The economic data are provided in Table 17.1. 

Steam turbine, Condenser, Feedwater heater, Deaerator... 

Tube side (SO) Piping (Hot leg) Steam turbine Condenser Grand steam condenser Condensate pump - Low pressure Feedwater heater- Deaerator Feedwater pump - High... 

Oil-Free Water OU-fiee storm runoff Steam turbine condensate... 

Parameters Feedwater Reactor circulating water Reactor bleed water Saturated/reheated steam Turbine condensate... 

Space needs to be provided for the auxiliaries, including the lube oil and seal systems, lube oil cooler, intercoolers, and pulsation dampeners. A control panel or console is usually provided as part of the local console. This panel contains instmments that provide the necessary information for start-up and shutdown, and should also include warning and trouble lights. Access must be provided for motor repair and ultimate replacement needs to be considered. If a steam turbine is used, a surface condenser is probably required with a vacuum system to increase the efficiency. AH these additional systems need to be considered in the layout and spacing. In addition, room for pulsation dampeners required between stages has to be included. Aftercoolers may also be required with knockout dmms. Reference 8 describes the requirements of compressor layouts and provides many useful piping hints. 

Fossil Fuel-Fired Plants. In modem, fossil fuel-fired power plants, the Rankine cycle typically operates as a closed loop. In describing the steam—water cycle of a modem Rankine cycle plant, it is easiest to start with the condensate system (see Fig. 1). Condensate is the water that remains after the steam employed by the plant s steam turbines exhausts into the plant s condenser, where it is collected for reuse in the cycle. Many modem power plants employ a series of heat exchangers to boost efficiency. As a first step, the condensate is heated in a series of heat exchangers, usually sheU-and-tube heat exchangers, by steam extracted from strategic locations on the plant s steam turbines (see HeaT-EXCHANGETECHNOLOGy). 

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. 5. Relative energy flows showing power generation and heat losses in GJ/h for (a), boiler only (b), boiler + steam turbine (c) combined cycle employing gas turbine and (d), condensing steam for power only. To convert /h to Btu/h, multiply by 0.95 x 10 . ...

Nonautomatic-Extraction Turbine, Condensing or Noncondensing Steam is extracted from one or more stages, but without means for controlling the pressures of the extrac ted steam. 

It is advantageous to have the expander generate its refrigeration at the lowest possible temperature in the process (see Fig. 29-45), and this frequently encounters the condensation temperature of the pi ocess stream. Steam-turbine pracrice advises against operating on... 

Specimen Location Steam turbine surface condenser... 

Electric motors may be considered in cases where it is considered advantageous to export surplus steam outside the nitric acid plant. Condensing steam turbines are normally used to bridge the power deficit. Extraction-condensing turbines make it possible to use some of the available steam for heating purposes. 

Dearation can be either vacuum or over pressure dearation. Most systems use vacuum dearation because all the feedwater heating can be done in the feedwater tank and there is no need for additional heat exchangers. The heating steam in the vacuum dearation process is a lower quality steam thus leaving the steam in the steam cycle for expansion work through the steam turbine. This increases the output of the steam turbine and therefore the efficiency of the combined cycle. In the case of the overpressure dearation, the gases can be exhausted directly to the atmosphere independently of the condenser evacuation system. 

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