Steam turbine integration

Steam turbine integration. Figure 6.32 shows a steam turbine expansion on an enthalpy-entropy plot. In an ideal turbine, steam... 

Figure 6.33 shows a steam turbine integrated with the process above the pinch. Heat Qhp is taken into the process from high-pressure steam. The balance of the hot utility demand Qlp is taken... 

Figure 6.33 Integration of a steam turbine with the process.

Expander-compressor shafts are preferably designed to operate below the first lateral critical speed and torsional resonance. A flame-plated band of aluminum alloy or similarly suitable material is generally applied to the shaft in the area sensed by the vibration probes to preclude erroneous electrical runout readings. This technique has been used on hundreds of expanders, steam turbines, and other turbomachines with complete success. Unless integral with the shaft, expander wheels (disks) are often attached to the shaft on a special tapered profile, with dowel-type keys and keyways. The latter design attempts to avoid the stress concentrations occasionally associated with splines and conventional keyways. It also reduces the cost of manufacture. When used, wheels are sometimes secured to the tapered ends of the shaft by a common center stretch rod which is pre-stressed during assembly. This results in a constant preload on each wheel to ensure proper contact between wheels and shaft at the anticipated extremes of temperature and speed. 

The problem table cascade for a process is given in Table 23.11 below for A7 = 30°C. This process is to be integrated with a steam turbine in a cogeneration scheme. The inlet steam is at 41 barg and 400°C. 

In a Natural Gas Combined Cycle (NGCC) or an Integrated Gasification Combined Cycle (IGCC), the steam produced from the waste heat boiler is converted into extra electrical power in the steam turbines. Consequently, for hydrogen production, the steam use must be kept as low as possible. 

Lokurlu A., Pruscheck R. (1999) Simulation of advanced SOFC power plants with gas and steam turbine cycles on the basis of integrated coal gasification (IGFC). In Pmceeedings of the 6th International Symposium on Solid Oxide Fuel Cells (SOFC IV), Honolulu, HI, pp. 439-446. 

Multiple-step variable-speed fan control, type d. is best applied with steam-turbine drives. In aplant with ac auxiliary motor drives, slip-ring motors with damper integration must be used between steps, making the installation expensive. Although dc motor drives would be less costly, few power plants other than marine propulsion plants have direct current available. And since marine units normally operate at full load 90 percent or more of the time, part-load operating economics are unimportant. If steam-turbine drive will be used for the fans, plot the power-input curve LMD, using data from the fan manufacturer. 

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