Boiler turbo generator

Linear programming Boiler/turbo generator system (11.4) Thermal cracker (14.1) >. i Planning and scheduling (16.1)... 

EXAMPLE 11.4 BOILER/TURBO-GENERATOR SYSTEM OPTIMIZATION... 

Example 11.4 Boiler/Turbo-Generator System Optimization 435... 

Our case-study corresponds to a stochastic version of the boiler/turbo generator system problem presented by Edgar et al. (2001). The system may be modeled as a set of linear constraints and a linear objective function. The demand on the resources are considered as uncertain variables in the problem. The distributions used for the demands are shown... 

Figure 3. Case-study boiler/turbo generator system (Edgar et al., 2(X)I).

Equipment one medium pressure boiler (43 bar, 410 C, 115 t/h of steam, 53 t/h of bagasse) seven low-pressure boilers (22 bar, 280 C, 440 l/h of steam, 227 t/h of bagasse) two 43 bar-back pressure-turbo-generator sets (12 MW) four 22 bar-back pressure-lurbo-generator sets (7.2 MW) 22 bar-back pressure-steam turbines for mechanical driving. Exhaust steam at 2.5 bar to the process. 

Steam condensers (after turbo generator sets) are used to maintain the low pressure of turbine exhausts as well as to recover condensate for recycle to the boiler feedwater tank. Here it is necessary not to subcool the condensed hquid, so that the maximum heat recovery can be done (by obtaining condensate at as high a temperature as possible. The configuration of steam inlet nozzle and cooling water inlet/ outlet nozzles etc should be designed accordingly. 

On Friday 9th March 1982, I had been working on shift as an Assistant Shift Manager on the steam side - i.e. the turbo-generator and boiler side of the plant -for maybe six months. I had still only been working at PFR for about 2.5 years, which I am sure most power station engineers would say is not enough time to be in a shift operations management role. 

Trawsfynydd is situated on the artificial lake of that name ereated some 30 years ago as a storage reservoir for the Maentwrog hydroeleetrie power station and lies within the Snowdonia National Park, North Wales. The station eon-sists of two reactors, housed in spherical-type pressure vessels made of steel, 3 2 in. thick, with an internal diameter each of 61 ft. Each reactor supphes heat to six boiler units. Generating plant comprises four 3000 rpm turbo alternators each with a rated output of 145 MW at 0.8 power faetor (lagging). The total guaranteed net output of the station in megawatts sent is 500 MW. 

Significant energy conservation is achieved by the well-established method of combined heat and power generation (cogeneration). The heat is usually in the form of intermediate or low-pressure steam, and the power as direct mechanical drives or as electricity generated with turbo-altemators. The choice of systems is usually between back-pressure steam turbines, or gas turbines with waste-heat boilers for the process steam. The amount of power generated is usually determined by the demand for heat. 

Process plants are for the most part dependent on electric power for motive purposes, to drive the process equipment and the materials transport systems. Other types of driver, in particular the steam turbine, have sometimes been employed, especially for major drives such as turbo-compressors (with which a turbine driver has a natural compatibility in terms of speed and speed variation), and in plants where steam is generated for process consumption or as a by-product in waste-heat boilers. Gas engine drivers (for reciprocating compressors) and gas turbines (for turbo-compressors) are also often employed for... 

Hinkley point is located on the north coast of Somerset on the Bristol Channel, some 8 miles north-west of Bridgewater. The A station consists of two reactors housed in steel spherical pressure vessels of 67 ft diameter, made of plates 3 in. thick. Each reactor has six boilers. Generating plant consists of six 3.5 MW turbo alternators and three 33 MW turbo alternators to provide auxiliary supplies. Total output of the station is 500 MW, which is fed into the 75 kV Supergrid system running between Melksham and Taunton. 

Each steam generator was of single-wall tube-in-shell design. The evaporators were of the forced-circulation type, with each of the three circuits having a steam drum and a boiler circulating pump. Superheated steam from the three circuits flowed to a common header to drive a 300MW turbo-alternator. The main feed was via a 100% duty steam-driven pump with... 

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