7/27/2019 HEX LP

1/1

Tubular Heat Exchanger Rating Sheet

Project Project No.

Item No. Service By Date/Time 19-Nov-13 12:46

Step 1. Input flows, conditions and properties data for shellside and Step 4. Start configuring the exchanger. Begin with the total calculated

tubeside. transfer coefficients to this point (i.e., not including shellside h):

Tube Side Shell Ustart= 120

Feed Water Fluid Name LP Steam On that basis, assumed Uo= 315

3 54 283.0 Flow (M), lb/h 30 994.0 Then the required transfer A = 7 219 ft2

114.8 Temp. in,oF 222.8 Number of tubes required = 1 484

206.6 Temp. out,oF 131 Reset tubes/pass (Step 3), then no. of passes = 2

Av. Density 61.089 , lb/ft3

0.0417 Total tube count = 450Av. Viscosity 0.397 , cP 0.012 Tubeside P (incl. returns) = 1.408 psi

Av. Heat Capacity 1.007 cp, Btu/lboF 0.4814 Actual effective transfer area, A = 2 189 ft

Heat Exchanged 3 27 44 337 Q, Btu/h 3 27 45 161

Av. Thermal Conductivity 0.384 k, Btu/hftoF 0.1937

Fouling Resistance 0.0002 R, ft2h

oF/Btu 0.0002 Step 5. Select tube arrangement Tube Pitch 0.94 in.

Prandtl No. 2.52 cp/k 0.07 and estimate shell diameter Pattern Tri

Uncorrected MTD 16.0oF Shell ID from Tube Count Tables 27 in.

Corrected MTD 14.4oF Select Baffle Spacing 6.75 in.

Number of Baffles = 43Flow Area across Bundle, as= 0.256 ft

Step 2. Input tubing OD, BWG and Tube OD 0.7500 in. Equivalent Diameter, de(see table) = 1.080 in.

length (can be trial and error). BWG 16 Mass Velocity, Gs= 1 21 157 lb/hft2

Tube ID, d = 0.620 in. Shellside Reynolds No., NRe= 8 78 010

Tube Length, L = 24.78 ft. Shellside Friction Factor = 0.00089

Flow area per tube, at= 0.302 in.2

Shellside P = 0.282 psi

Effective transfer area per tube = 4.866 ft Outside Transfer Factor, jh= 643.9

Outside Film Coefficient, ho= 584

Calculated Uo= 300.7

Step 3. Estimate the number of Tubes/pass = 225 Check: % difference, Ucalc.vs Uassum.= -4.7% tubes per tube pass. lb/h per tube = 1 575 Uclean= 341.8

Av. velocity, fps = 3.41

Tubeside Reynolds No., NRe= 40 409

Tubeside Friction Factor, f = 0.010

P per pass, psi = 0.38

Nusselt number, Nr = 11.09

Inside Film Coefficient, hi= 824 required.

Btu/hft2oF

Step 6. Check tubeside velocity andP, shellside P. If too high or too low,

adjust tube length, number of tubes per pass, number of passes, and/or shell

baffle spacing. Remember to reset shell diameter from tube count tables, as

Low Pressure Feed water Heater sizing

Feed water Heating

Btu/hft2oF