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Temperature-Interval TI Method

Returning to Example 10.1, the temperature-interval (TI) method is used for the calculation of MER [Pg.307]

The first step in the TI method is to adjust the source and target temperatures using Ar i . Somewhat arbitrarily, this is accomplished by reducing the temperatures of the hot streams by Ar, i , while leaving the temperatures of the cold streams untouched as follows  [Pg.307]

It is noted that initially, no energy is assumed to enter this interval from a hot utility, such as steam ati higher temperature that is, Ssteam = 0. Hence, 30 x 10 Btu/hr arc available and flow down as aieskl ual, R, into the next lowest interval 2 that is, /J = 30 X 10 Btu/hr. Interval 2 involves streams HI, H2, and C2 between 235°F and 240°F AT = 5 F), and hence, the enthalpy difference is [Pg.308]

When this is added to the residual from interval 1, / this makes the residual from interval 2, k, = 32.5 X 10 Btu/hr. Note that no temperature violations of Ar ,i occur when the streams are mabhedin interval 2 because the hot stream temperatures are reduced by AT. Interval 3, 180 F to 235T (AT= 55°F), involves aU four streams, and hence, the enthalpy difference is —82.5 X 10 Btu/hr as detailed in Table 10.1, making the residual from interval 3 equal to (32.5 — 82.5) x 1(X = —50 X 10 Btn/h. Similarly, the enthalpy differences in intervals 4 and 5 are 75 X Kf and —15 X Kf Btu/hr, respectively, with the residuals leaving these intervals being 25 x 10 and 10 X 10 Btu/hr. Note that fcr [Pg.308]

Energy Flows between Intervals Initial Pass Final Pass [Pg.308]


A closer examination of the temperature-interval (TI) method shows that the minimum hut and cold utilities can be calculated by creating and solving a linear programming (LP) problem, as discussed in Section 18.4. This approach is illustrated in the example that follows. [Pg.312]

Be able to determine the minimum cooling and heating utilities (MER targets) for a network of heat exchangers using the temperature-interval (TI) method, the composite-curve method, or the formulation and solution of a linear program (LP). [Pg.360]

A different approach consists of stepwise changing the adsorbent temperature and keeping it constant at each of the prefixed values Tx, Ts,. . ., Tn for a certain time interval (e.g. 10 sec), thereby yielding the so-called step desorption spectra s(81-85). The advantage of this method lies in a long interval (in terms of the flash desorption technique) for which the individual temperatures Ti are kept constant so that possible surface rearrangements can take place (81-83). Furthermore, an exact evaluation of the rate constant kd is amenable as well as a better resolution of superimposed peaks on a desorption curve (see Section VI). What is questionable is how closely an instantaneous change in the adsorbent temperature can be attained. This method has been rarely used as yet. [Pg.362]

The second cleaning method, specific to TSDC measurements and which may be apphed in our case, is due to Bucci et al. [23]. It consists of first polarizing the material at a temperature T, such that T 2 and removing the field at temperature Td such that [Pg.34]


See other pages where Temperature-Interval TI Method is mentioned: [Pg.525]    [Pg.302]    [Pg.307]    [Pg.525]    [Pg.302]    [Pg.307]    [Pg.423]    [Pg.13]    [Pg.409]    [Pg.262]    [Pg.312]    [Pg.323]    [Pg.367]    [Pg.1161]    [Pg.543]    [Pg.126]    [Pg.67]    [Pg.72]    [Pg.209]    [Pg.431]    [Pg.222]   


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Temperature interval method

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