ARNOLD, K. (1999). Design of Gas-Handling Systems and Facilities (2nd ed.) Episode 1 Part 4 pdf

Heat Exchangers 61

Table 3-3

Tube Materials

Sweer Senice Glycol, MEA, and Sulfinol

Temperatures above ~20°F, A-2 14 ERW or A- 1 79 (seamless)

-50°F to -21°F, A-334 Grade 1

- 1 50°F to -5 1 °F, A334 Grade 3

Sour ami Low Temperature

304 SS

Brackish Water

90/10Cu-Ni

70/30 Cu-Ni Use higher nickel content the more brackish the water

Sizing

The required heat duty, film coefficients, conductivity, etc. for a shell￾and-tube heat exchanger can be calculated using the procedures in Chap￾ter 2, Approximate U-values are given in Table 2-8.

In the basic heat transfer equation it is necessary to use the log mean

temperature difference. In Equation 2-4 it was assumed that the two flu￾ids are flowing counter-current to each other. Depending upon the con￾figuration of the exchanger, this may not be true. That is, the way in

which the fluid flows through the exchanger affects LMTD. The correc￾tion factor is a function of the number of tube passes and the number of

shell passes.

Figures 3-10 and 3-11 can be used to calculate a corrected LMTD

from the formula.

where Tj = hot fluid inlet temperature, °F

T2 = hot fluid outlet temperature, °F

T3 = cold fluid inlet temperature, °F

T4 = cold fluid outlet temperature, °F

AT] = larger temperature difference, °F

AT2 = smaller temperature difference, °F

LMTD = log mean temperature difference, °F

F = correction factor

(text continued on page 64)

62 Design of GAS-HANDLING Systems and Facilities

Figure 3-10. LMTD correction factors. (From Gas Processors Suppliers Association,

Engineering Data Book, 9th Edition.)