Plant efficiency calculations

TABLE 14.11 Results of power plant efficiency calculations ... 

Expander performance will shift as plant conditions—such as gas flowrate, gas inlet, and discharge pressure—gas composition, and inlet temperature change. Calculation of expander diermal efficiency from field data is not accurate because expander discharge flow normally consists of two phases, gas and liquid. Efficiency calculations should always be cross-checked with the shaft power produced before any decision on expander performance is made. 

Subsequently, in Chapter 4, we deal with cycles in which the turbines are cooled. The basic thermodynamics of turbine cooling, and its effect on plant efficiency, are considered. In Chapter 5, some detailed calculations of the performance of gas turbines with cooling are presented. 

Chapter 5. Full calculations of plant efficiency A new temperature difference ratio is written as... 

Fig. 6.4 then shows a more complete calculation of plant efficiency for varying S. The optimum condition of maximum efficiency is reached at 5 = 0.208. The picture changes for a gas turbine with a higher pressure ratio, for which the increase to maximum efficiency is less, as is the optimum value of S 2]. 

Even for this simplest CCGT plant, iterations on such a calculation are required, with various values of p, in order to meet the requirements set on T, the steam turbine entry temperature, and 7s (the calculated value of 7s has to be such that the dewpoint temperature of the gas (7jp) is below the economiser water entry temperature (7b) and that may not be achievable). But with the ratio /i satisfactorily determined, the work output from the lower cycle Wl can be estimated and the combined plant efficiency obtained from... 

With the fuel energy input known from the calculation of the gas turbine plant performance, F = Aff[CV]o, the combined plant efficiency is determined as... 

A gas turbine plant with an overall efficiency t]cq = 0.25 matching a heat load Acc, = 2.25 is again considered as the basic CHP plant also implied is a non-useful heat rejection ratio (Cnu)cg( cg = [1 ( cg)( g + 1)1 =. 3/16. For FESR calculations, we again take the conventional plant efficiency as 0.4 and the conventional boiler efficiency as 0.9. At the fully matched condition the.se assumptions previously led to EUF = 0.8125 and FESR = 0.2. 

A thermodynamic analysis of the energy requirements of desalting processes is presented, to clarify the conditions under which such calculations are valid. The effects of departure from isothermal operation, finite product recovery, differential as opposed to single-stage operation, and salt concentration in the feed are examined. A comparison shows that there is essentially no difference between the energy requirements for a distillation and a freezing process. The minimum heat consumption and maximum number of efFects for a multiple-effect evaporation plant are calculated. The above analysis leads to the conclusion that efficiencies in the range 10 to 20% will be very difficult to achieve. 

Eerformance in terms of pounds of fuel consumed per horsepower-our. For electric power plants, fuel consumption is reported in terms of kilowatts. Auxiliaries included with engine-efficiency calculations vary with industry practice. 

Simple models for performance simulation have been developed for stationary flow situations, with the options of verifying the voltage-current relations and calculating the overall efficiency imder consideration of total plant auxiliary power and heat inputs. The efficiency calculated with such models exhibits a few percent efficiency improvement from raising the pressure above ambient by the factors considered above and, as expected, a decline with increased gas flow rates (Simon et al, 2003). 

The above equation was used for scale-up calculations and design of both the pilot plant and full-scale Electropulse Column. A total of 18 experimental runs for uranium(VI) electrolytic reduction was performed on the 20-cm diameter pilot-scale column. (10) As shown in Figure 4, the predicted reduction efficiency calculated from equation (4) correlated well with the experimental values obtained during these runs. The same good correlation between the predicted and experimental R(u) values was achieved later during cold uranium tests in the full-scale unit (Figure 4). The accuracy of correlation was within the range of 6%. 

Association (United States) calculates efficiencies based on the lower heating value (LH V) for gas fuels and the higher heating value for oil fuels. It is general practice to report gas-engine performance in terms of British thermal units per horsepower-hour (LHV) and oil-engine performance in terms of pounds of fuel consumed per horsepower-hour. For electric power plants, fuel consumption is reported in terms of kilowatts. Auxiliaries included with engine-efficiency calculations vary with industry practice. 

The plant capital can be depreciated by various methods K6lbel 1967). For a cost efficiency calculation it is generally sufficient to assume hnear depreciation over a ten-year utilization period. The annual depreciation is then 10% of the plant capital ... 

Was the meter really a problem The primary reasons for suspicion were the calculated plant efficiency (with no operating history, this figure was questionable) and the calculated UNACCOUNTED FOR GAS, the accuracy of which was also questionable. 

SNG meter flow computer. The overall plant efficiency is also calculated which is another check on both the process and the metering (Figure 7). 

Design Basis is the design inputs, the design constraints, and the design analysis and calculations, It includes topical areas such as seismic qualification, fire protections, and safe shutdown, It encompasses consideration of such factors as plant availability, plant efficiency, costs, and maintainability, and that subset that relates to safety and the authorization basis. 

The importance of the moderator cost to the power cost for a nuclear plant can be seen by the very approximate data indicated in Table VI. In this table, the cost contribution of the moderator material has been calculated for reactor conditions typical of some gas-cooled reactors. The capital cost of the moderator in dollars per installed kilowatt(e) is related to the unit cost of the moderator, the moderator/fuel weight ratio, the reactor specific power, and the plant efficiency by... 

Reduced penalty for higher heat rejection temperatures. The capital costs of dry cooling systems can be reduced by rejecting heat at a higher temperature but with the penalty of lower plant efficiency. That penalty becomes smaller as the peak temperature of the power cycle increases. For the AHTR Brayton cycle with a minimum helium temperature of 35°C, the losses in efficiency for a 10°C rise in the compressor inlet temperature were calculated to be 1.5, 1.3, and 1.1%, respectively, for AHTR peak coolant temperatures of 705, 800, and 1000°C. 

Thirdly, due to its efficient calculation engine, initial LoC estimates for entire sites can be calculated in a matter of minutes which makes it very easy to minimize the LoC frequencies in process plants in the future. 

Plant heat balance and the thermal efficiency calculation are in ref. [114]. This reference also includes the two-dimensional coupled core calculation procedure for the thermal reactor. 

The calculated thermal efficiency represents also the power plant efficiency. 

In Section 3.6 we described briefly a simple steam power plant and in Example 3.12 we calculated the thermal (or power plant) efficiency of such a plant. For this purpose we used an arbitrary set of operating... 

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