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Power Plant Technology By Wakil Pdf Free 57 'LINK'

In seawater desalination, the energy efficiency of practical processes is expressed in kWh_electricity or low-grade-heat per m3 of water produced, omitting the embedded energy quality underlying their generation processes. To avoid thermodynamic misconceptions, it is important to recognize both quality and quantity of energy consumed. An unmerited quantitative apportionment can result in inferior deployment of desalination methods. This article clarifies misapprehensions regarding seeming parity between electricity and thermal sources that are sequentially cogenerated in power plants. These processes are represented by heat engines to yield the respective maximum (Carnot) work potentials. Equivalent work from these engines are normalized individually to give a corresponding standard primary energy (QSPE), defined via a common energy platform between the adiabatic flame temperature of fuel and the surroundings. Using the QSPE platform, the energy efficiency of 60 desalination plants of assorted types, available from literature, are compared retrospectively and with respect to Thermodynamic Limit.

power plant technology by wakil pdf free 57

As electricity is one of the convenient forms of derived energy, it is used to power work-driven membrane-based reverse osmosis (RO) desalination processes. By defining the 2nd Law Efficiency as \(\eta ^\prime\prime = \fracW_\mathrmaW_\mathrmC\) for an engine, where the actual work input is normally known via electricity consumption of processes. From the decomposed gas and steam turbines that produced electricity of a CCGT plant, a conversion factor (CF) can now be defined, based on the consumption of the standard primary energy of these engines to the actual electricity output, i.e.,

Superficially, the inverse of \(\mathrmCF_\mathrmelec\) may appear similar to the conventional energy efficiency of a power plant. However, a closer examination of its derivation reveals a fundamental difference where it employs the standardized QSPE, and not QH. The latter term expresses only the quantitative aspect and makes no allowance for the quality of energy consumed.

Using the physically meaningful conversion factors, namely CFelec and CFth, these factors transform the absolute values (quantity and quality) of derived energy consumed by diverse desalination methods to the common platform primary energy consumption, enabling a cross comparison of energy efficiency from all desalination methods. In brief, the thermodynamic framework provides the common energy platform that served two key roles: Firstly, the fractional apportionment of standardized primary energy consumption, conducted on the cascaded processes of CCGT to the respective electricity, low-grade thermal sources, etc., yielded the causal calibrated conversion factors for the derived energy to power all diverse processes in industry. This calibration of conversion factors is performed with the best power plant systems available hitherto. Secondly, the calibrated conversion factors enable the conversion of specific energy consumption of practical desalination plants, consuming either electricity or thermal sources, into a common energy platform of QSPE. The relative consumption of standardized QSPE for water produced from all types desalination methods can now be compared accurately.

Since 1970s, many authors presented first law of thermodynamics for co-generation-based desalination processes fuel cost allocation. For example, Burly19 and Al-Sofi et al.20 utilized the enthalpy and flow rate of bleed steam to estimate the proportions primary fuel to desalination processes. Seven different methods for fuel cost allocation proposed by Wang et al.21 also based on energy of input streams and outputs. Hamed et al.22 presented energetic-based desalinated water cost for a real co-generation based desalination plant. Helal23 and Lozano et al.24 proposed tri-generation (power, desalination, and cooling) plant energetic analysis based on distribution of heat energy. The quantitative or energetic analysis may deemed sufficient for a comparative exercise only when the processes utilize same form of the energy, such as SWRO to SWRO and MED to MED. However, when the comparison is made across desalination processes having assorted forms of derived energy as input, quantative as well as qualitative analysis is required. This can be achieved by invoking the 2nd Law of thermodynamics and exergetic analysis approaches.

Although, number of publications are available on exergy analysis, but they only focused on system performances in case of single purpose plants and components performance improvement of the dual purpose plants. May authors presented second law of thermodynamic analysis of desalination processes with different efficiency definitions.25,26,27,28,29,30,31 For example, J.H. Lienhard et al.32 conducted a detailed exergetic analysis only for desalination processes. They presented the second law efficiency by considering desalination processes as a black box and the ideal work or thermodynamic limit for separation of dissolved salts in seawater is used as the Carnot work. They considered stand-alone processes for their analysis and it was not linked to co-generation based current practices. Similarly, K.H. Mistry et al.33,34,35 presented entropy generation in different desalination processes and second law efficiency without considering secondary energy generation processes, i.e., with no bearing to the best available co-generation processes being used in power generation industry of today. Such independent approaches, although correct in analyses by themselves, but do not reflect the chorological evolvement of efficient production of secondary or derived energy sources. Fitzsimons et al.36 summarized over 60 publications on exergy analysis but all are based on stand-alone processes analysis with differences in calculated values up to 80% due to various assumptions and calculation methodologies37,38.

In any separator device, the governing 2nd Law equations and efficiencies are representing the work and heat-driven desalination methods. The gas turbine cycle, including its all components, consume 58.22% of input fuel exergy while remaining exergy in exhaust gases is recovered through exhaust gases operated HRSG. The steam turbine cycle extract 38.95% of input fuel exergy via steam produced in HRSG and it also include internal losses in the cycle and part of steam exergy dumped in the condenser. The bleed steam for MED cycle, including heat input and thermal vapor compressor carries only 2.83% of input fuel exergy. The MED exergy proportion also includes the share condenser steam and un-accounted losses. For convenience of the engineers and scientists in the industry, the concept of conversion factors (CFs) is proposed to convert the derived energies input to the SPE input as summarized in Table 1. It shows that to produce one unit of electricity, power plant consume 2.012 unit of SPE. Similarly, one unit of SPE can produce 35.33 unit of low-pressure steam to operate MED.

A full-motion gimbal has additional problems of how to communicate power into and out of the flywheel, since the flywheel could potentially flip completely over once a day, precessing as the Earth rotates. Full free rotation would require slip rings around each gimbal axis for power conductors, further adding to the design complexity.

In 2013, Volvo announced a flywheel system fitted to the rear axle of its S60 sedan. Braking action spins the flywheel at up to 60,000 rpm and stops the front-mounted engine. Flywheel energy is applied via a special transmission to partially or completely power the vehicle. The 20-centimetre (7.9 in), 6-kilogram (13 lb) carbon fiber flywheel spins in a vacuum to eliminate friction. When partnered with a four-cylinder engine, it offers up to a 25 percent reduction in fuel consumption versus a comparably performing turbo six-cylinder, providing an 80 horsepower (60 kW) boost and allowing it to reach 100 kilometres per hour (62 mph) in 5.5 seconds. The company did not announce specific plans to include the technology in its product line.[23]

Flywheel Energy Storage Systems (FESS) are found in a variety of applications ranging from grid-connected energy management to uninterruptible power supplies. With the progress of technology, there is fast renovation involved in FESS application. Examples include high power weapons, aircraft powertrains and shipboard power systems, where the system requires a very high-power for a short period in order of a few seconds and even milliseconds.Compensated pulsed alternator (compulsator) is one of the most popular choices of pulsed power supplies for fusion reactors, high-power pulsed lasers, and hypervelocity electromagnetic launchers because of its high energy density and power density, which is generally designed for the FESS.[38] Compulsators (low-inductance alternators) act like capacitors, they can be spun up to provide pulsed power for railguns and lasers. Instead of having a separate flywheel and generator, only the large rotor of the alternator stores energy. See also Homopolar generator.[39]


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