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Site Composite Curves

A method of thermodynamic analysis for site steam systems will next be developed to allow the thermal loads and levels on a complete site to be studied. For this, a temperature-enthalpy picture for the whole site is needed, analogous to the grand composite curve for an individual process, as developed in Chapter 16. There are two ways in which such curves can be developed. The first relates to a new design situation. [Pg.487]

In setting the appropriate amount of heat recovery across the site through the steam system, various trade-offs need to be considered. Before this can be done, the cogeneration implications of the site heat recovery need to be quantified. [Pg.490]


One further point needs to be noted regarding the construction of the site composite curves. The temperatures are shifted over and above the shift included in the construction of the grand composite curve. The original hot and cold streams are shifted by ATmin/2 to produce the grand composite curve. Site composite curves are shifted by an additional ATmin/2 to give a total AT shift of ATmin, as illustrated in Figure 23.2913. If different values of ATmin apply to different processes, then each set of process data is given its individual shift in A Tmin before the steams are combined in the construction of the site composite curves. The concept of individual shifts for A Tmin was discussed in Chapter 16. [Pg.488]

The steam profiles in Figure 23.30 touch the site profiles. This does not imply heat transfer with AT = 0. The temperature difference built into the construction of the site composite curves ensures feasible heat transfer. Each time a steam profile touches a site composite curve, this implies ATmin. In practice, the streams in the construction of the site... [Pg.488]

Figure 23.31 shows the site composite curves but now, relating to a retrofit situation. This time, the temperatures... [Pg.489]

Site composite curves can be used to represent the site heating and cooling requirements thermodynamically. This allows the analysis of thermal loads and levels on site. Using the models for steam turbines and gas turbines allows cogeneration targets for the site to be established. Steam levels can be optimized to minimize fuel consumption or maximize cogeneration. A cost trade-off needs to be carried out in order to establish the optimum trade-off between fuel requirements and cogeneration. [Pg.508]

Figure 4.11 Total site composite curves of the biomass-to-ethylene plant... Figure 4.11 Total site composite curves of the biomass-to-ethylene plant...
A new design situation would start from the grand composite curves of each of the processes on the site and would combine them together to obtain a picture of the overall site utility system12. This is illustrated in Figure 23.27, where two processes have their heat sink and heat source profiles from their grand composite curves combined to obtain a site hot composite curve and a site cold composite curve, using the procedure developed for composite curves in Chapter 16. Wherever there is an overlap in temperature between streams, the heat loads... [Pg.487]

Figure 23.28 Sometimes, the details of the grand composite curve pockets should be included in the site profiles. Figure 23.28 Sometimes, the details of the grand composite curve pockets should be included in the site profiles.
Figure 23.44 shows a site grand composite curve to illustrate the definition of the site heating demand. The steam demand for the processes on the site is defined by (see Figure 23.44)17 ... [Pg.496]

With monomers of differing solubility, however, the actual concentration ratio of the monomers in the oil phase, the site of the polymerization, differs from the overall monomer concentration ratio. The effective monomer concentration ratio can be calculated from the overall concentration ratio and the partition coefficients. When the polymer composition is plotted against the actual monomer concentration ratio in the oil phase, a curve results which is superimposable on the composition curve of the copolymer produced by bulk polymerization. [Pg.245]

The a—time curves for the oxidation reactions [60] of both nickel maleate (534—568 K) and nickel fumarate (548—583 K) were similar to those characteristic of each reactant in vacuum, though E values were reduced to 150 10 kJ mole-1. It was concluded that the distributions of nucleation sites and subsequent patterns of product development were little altered by the change in composition of product from Ni/C (and Ni3C) to NiO. This difference, however, significantly changed the temperature coefficient and stoichiometry of the interface processes, since all carbonaceous material in the reactants was converted to CO2. A constant value of E (150 kJ mole-1) was thus found for the oxidations of the four nickel salts studied [60], the maleate, fumarate, formate and malonate. [Pg.227]

Fig. 4.3. (A) Composite multispecies benthic foraminiferal Mg/Ca records from three deep-sea sites DSDP Site 573, ODP Site 926, and ODP Site 689. (B) Species-adjusted Mg/Ca data. Error bars represent standard deviations of the means where more than one species was present in a sample. The smoothed curve through the data represents a 15% weighted average. (C) Mg temperature record obtained by applying a Mg calibration to the record in (B). Broken line indicates temperatures calculated from the record assuming an ice-free world. Blue areas indicate periods of substantial ice-sheet growth determined from the S 0 record in conjunction with the Mg temperature. (D) Cenozoic composite benthic foraminiferal S 0 record based on Atlantic cores and normalized to Cibicidoides spp. Vertical dashed line indicates probable existence of ice sheets as estimated by (2). 3w, seawater S 0. (E) Estimated variation in 8 0 composition of seawater, a measure of global ice volume, calculated by substituting Mg temperatures and benthic 8 0 data into the 8 0 paleotemperature equation (Lear et al., 2000). Fig. 4.3. (A) Composite multispecies benthic foraminiferal Mg/Ca records from three deep-sea sites DSDP Site 573, ODP Site 926, and ODP Site 689. (B) Species-adjusted Mg/Ca data. Error bars represent standard deviations of the means where more than one species was present in a sample. The smoothed curve through the data represents a 15% weighted average. (C) Mg temperature record obtained by applying a Mg calibration to the record in (B). Broken line indicates temperatures calculated from the record assuming an ice-free world. Blue areas indicate periods of substantial ice-sheet growth determined from the S 0 record in conjunction with the Mg temperature. (D) Cenozoic composite benthic foraminiferal S 0 record based on Atlantic cores and normalized to Cibicidoides spp. Vertical dashed line indicates probable existence of ice sheets as estimated by (2). 3w, seawater S 0. (E) Estimated variation in 8 0 composition of seawater, a measure of global ice volume, calculated by substituting Mg temperatures and benthic 8 0 data into the 8 0 paleotemperature equation (Lear et al., 2000).

See other pages where Site Composite Curves is mentioned: [Pg.487]    [Pg.488]    [Pg.488]    [Pg.489]    [Pg.489]    [Pg.492]    [Pg.493]    [Pg.510]    [Pg.487]    [Pg.488]    [Pg.488]    [Pg.489]    [Pg.489]    [Pg.492]    [Pg.493]    [Pg.510]    [Pg.487]    [Pg.488]    [Pg.489]    [Pg.490]    [Pg.491]    [Pg.492]    [Pg.492]    [Pg.137]    [Pg.209]    [Pg.560]    [Pg.47]    [Pg.58]    [Pg.586]    [Pg.460]    [Pg.557]    [Pg.558]    [Pg.171]    [Pg.270]    [Pg.42]    [Pg.15]    [Pg.93]    [Pg.110]    [Pg.286]    [Pg.317]    [Pg.53]    [Pg.55]    [Pg.330]    [Pg.17]    [Pg.105]    [Pg.490]   


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