Page 125 - Chemical Process Equipment - Selection and Design

6.3. LIQUIDS 97

EXAMPLE 6.4 1.6364
Pressure Drop in 8hisothermd Liquid Flow = [ln[0.135(0.00141) + 6.5/NRJ2 ’
Qii is pumped at the rate of 60001b/hr through a reactor made of
commercial steel pipe 1.278in. ID and 2000ftlong. The inlet
condition is 4WF and 750psia. The temperature of the outlet is The differential pressure is given by
930°F and the pressure is to be found. The temperature varies with
the distance, L ft, dong the reactor according to the equation
T = 1500 - 1100 exp(-0.0003287L) (“F)
=0.568fdL, psi,
The viscosity and density vary with temperature according to the P
equations P = 750 - cyf = 750 - 6 IdL.
dL
( : : ; . ;
p =exp ----.lo76 6
The pressure profile is found by integration with the
p = 0.936 - 0.005361; g/mL. trapezoidal rule over 200 ft increments. The computer program and
the printout are shown. The outlet pressure is 700.1 pia.
Round’s equation applies for the friction factor: For comparison, taking an average temperature of 665”F,

NRe ~ 41iz = 4(6000) - 29,441 p = 1.670, p = 0.697
=
nDp n(1.278/12)2.42;u p.1 ’
NRe = 17,700, f = 0.00291,
Pout = 702.5.

- -

488. G1 2.3 4.85 75Ki.Gi
4.4 5.99 743.6
478. Q -
535.5 1.5 3.49 737.9
596.9 11.6 3.16 732.8
654.4 16.7 2.95 727.9
788.2 22 7 2.86 723.2
758.5 29.5 2.69 718.5
895.7 37.1 2.61 713.9
849.9 45.2 2.55 799.3
891.3 53.8 2.59 784.7
939.8 62.7 2.47 780.1

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