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Shell and Tube Heat Exchanger Calculation

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00:00:00.000
this is the shell and tube heat
00:00:01.670 00:00:01.680 exchanger calculator and available at
00:00:04.010 00:00:04.020 Chemical Engineering now calm this is a
00:00:06.920 00:00:06.930 very broad-based form applicable to a
00:00:09.169 00:00:09.179 number of different design types that is
00:00:11.629 00:00:11.639 it applies to the calculations related
00:00:13.549 00:00:13.559 to heat exchanger types such as double
00:00:15.410 00:00:15.420 pipe Multi tube multi pass single-phase
00:00:18.650 00:00:18.660 or condensing phases with or without the
00:00:20.840 00:00:20.850 presence of non-condensibles horizontal
00:00:23.660 00:00:23.670 vertical or inclined tube arrangements
00:00:26.120 00:00:26.130 axial or cross flow patterns in the
00:00:28.429 00:00:28.439 shell and are bare or low fin tubes the
00:00:31.790 00:00:31.800 layout of the form has the tube side
00:00:33.530 00:00:33.540 information on the left and the shell
00:00:35.209 00:00:35.219 side information on the right side with
00:00:37.580 00:00:37.590 the process related information at the
00:00:39.290 00:00:39.300 top of the form and the exchanger
00:00:40.760 00:00:40.770 specific information at the bottom this
00:00:43.069 00:00:43.079 form is used in conjunction with the LM
00:00:45.080 00:00:45.090 TD calculation form which will you shall
00:00:47.779 00:00:47.789 see in a moment the calculator generally
00:00:50.060 00:00:50.070 solves problems in the direction that
00:00:51.470 00:00:51.480 determines the required heat transfer
00:00:53.389 00:00:53.399 area and fluid pressure drops although
00:00:56.180 00:00:56.190 as with all calculators at Chemical
00:00:57.920 00:00:57.930 Engineering comm a quick and simple
00:00:59.930 00:00:59.940 trial and error MIT's the calculation of
00:01:02.180 00:01:02.190 any parameter of particular interest
00:01:04.179 00:01:04.189 considered this example in which we have
00:01:10.100 00:01:10.110 a heat exchanger available to us either
00:01:12.230 00:01:12.240 in the yard or available as a from a
00:01:14.750 00:01:14.760 used equipment provider and the question
00:01:17.300 00:01:17.310 is will it fit our requirements let's
00:01:20.030 00:01:20.040 look at the process requirements first
00:01:22.609 00:01:22.619 we want to see if we can use this to
00:01:24.800 00:01:24.810 cool 6500 pounds per hour liquid a from
00:01:29.120 00:01:29.130 180 degrees Fahrenheit to 110 degrees
00:01:33.530 00:01:33.540 Fahrenheit with with liquid B that is
00:01:36.140 00:01:36.150 available at ninety degrees Fahrenheit
00:01:38.200 00:01:38.210 but we cannot allow like liquid B to go
00:01:41.510 00:01:41.520 over 120 degrees Fahrenheit at the
00:01:43.670 00:01:43.680 outlet so we will do a heat balance and
00:01:46.999 00:01:47.009 calculate the required flow of B ideally
00:01:50.840 00:01:50.850 a close a closer approach in temperature
00:01:53.899 00:01:53.909 would would be more economical but the
00:01:56.090 00:01:56.100 hundred twenty degrees is provided by
00:01:57.709 00:01:57.719 our problem let's first notice that the
00:02:03.530 00:02:03.540 fluids
00:02:04.280 00:02:04.290 do not cross each other
00:02:08.040 00:02:08.050 first we'll calculate the amount of heat
00:02:10.900 00:02:10.910 that's transferred from fluid a so fluid
00:02:14.200 00:02:14.210 a transfers 150 2425 BTUs per hour that
00:02:21.160 00:02:21.170 means the flow of fluid B will be 5000
00:02:24.820 00:02:24.830 91 pounds per hour the fluid parameters
00:02:31.200 00:02:31.210 are all provided here on this form for
00:02:35.230 00:02:35.240 fluid a and for fluid B on the inlet and
00:02:39.610 00:02:39.620 outlet for our calculation however we're
00:02:42.730 00:02:42.740 going to have to know the average bulk
00:02:45.070 00:02:45.080 temperature the wall temperature and the
00:02:48.880 00:02:48.890 film temperature so the average shell
00:02:51.490 00:02:51.500 side bulb temperature is the average of
00:02:53.440 00:02:53.450 the inlet in the outlet so the 180 plus
00:02:57.730 00:02:57.740 110 divided by 2 is 145 similarly for
00:03:01.240 00:03:01.250 the tube side the average is 105 the
00:03:05.530 00:03:05.540 average wall temperature therefore is
00:03:07.060 00:03:07.070 145 plus 105 at is 125 for the film it's
00:03:12.790 00:03:12.800 the wall plus the shell / - it's 135 and
00:03:17.170 00:03:17.180 on the tube side it's 115 you could
00:03:20.860 00:03:20.870 either use these film temperatures or a
00:03:23.830 00:03:23.840 more conservative approach may very well
00:03:25.990 00:03:26.000 be to use the bulk temperatures now the
00:03:30.880 00:03:30.890 exchanger that is that is available to
00:03:34.240 00:03:34.250 us let's take a look at it it has two
00:03:39.370 00:03:39.380 tube passes 16 16 carbon steel tubes per
00:03:44.590 00:03:44.600 pass for a total of 32 tubes the tubes
00:03:47.620 00:03:47.630 are 20 feet long and have an OD of 0.75
00:03:50.530 00:03:50.540 inches a tube wall thickness of 0.6
00:03:54.479 00:03:54.489 0.065 inches they're arranged in a
00:03:57.820 00:03:57.830 triangular pattern of fifteen sixteenths
00:04:00.610 00:04:00.620 of an inch the outside diameter is 8
00:04:03.370 00:04:03.380 inches and has 19 baffles that are 12
00:04:06.280 00:04:06.290 inches apart and there's only one pass
00:04:08.110 00:04:08.120 on the shell so we're going to try using
00:04:10.420 00:04:10.430 fluid a on the shell and fluid B in the
00:04:13.870 00:04:13.880 tubes
00:04:20.560 00:04:20.570 so if we first calculate our LM TD we
00:04:24.860 00:04:24.870 have 180 over ha cooled to a 180 on the
00:04:29.900 00:04:29.910 hot fluid in cooled to 110 the cold
00:04:33.110 00:04:33.120 fluid comes in at 90 and is heated to
00:04:36.230 00:04:36.240 120 there's one pass on the shell and
00:04:39.860 00:04:39.870 two passes on the tube the log mean
00:04:44.270 00:04:44.280 temperature difference therefore is
00:04:45.970 00:04:45.980 twenty point five six
00:04:49.960 00:04:49.970 LM TD is twenty point five six so if we
00:04:56.750 00:04:56.760 jump over and we've input all of that
00:04:58.880 00:04:58.890 data into our our form we have two heat
00:05:02.330 00:05:02.340 transfer rate we got our LM TD we have
00:05:05.090 00:05:05.100 liquid in the tube liquid in the shell
00:05:06.920 00:05:06.930 we have all of our shell our tube side
00:05:10.880 00:05:10.890 information all of our shell side
00:05:12.740 00:05:12.750 process information we have a horizontal
00:05:16.940 00:05:16.950 tube we have our tube side information
00:05:19.820 00:05:19.830 our diameter number of tubes wall
00:05:22.250 00:05:22.260 thickness number of passes against it
00:05:25.190 00:05:25.200 our tube length carbon steel material
00:05:26.960 00:05:26.970 we've applied a filing factor of 0.005
00:05:30.470 00:05:30.480 in this example we're cross flow pattern
00:05:33.800 00:05:33.810 in the shell 8-inch diameter triangular
00:05:35.900 00:05:35.910 to pitch our pitches zero point there's
00:05:40.040 00:05:40.050 0.9375 inches nineteen baffles twelve
00:05:43.790 00:05:43.800 inches apart and again applied another
00:05:45.800 00:05:45.810 filing factor so our calculation will
00:05:49.880 00:05:49.890 show the inside and the outside clean
00:05:53.360 00:05:53.370 side coefficients the at the overall
00:05:56.120 00:05:56.130 coefficient u is twenty seven point nine
00:05:58.400 00:05:58.410 three the overall heat transfer area is
00:06:01.460 00:06:01.470 two hundred sixty five and a half square
00:06:04.130 00:06:04.140 feet of course we used thirty two tubes
00:06:09.610 00:06:09.620 and the total length of the tubes would
00:06:13.720 00:06:13.730 be 21 point 1 2 7 feet so this
00:06:19.750 00:06:19.760 exchangers slightly small but if we
00:06:22.180 00:06:22.190 eliminated these go file in fact errs we
00:06:27.280 00:06:27.290 would see that the exchanger would be 15
00:06:31.230 00:06:31.240 point 2 to 7 feet would be adequate and
00:06:35.350 00:06:35.360 we've also calculated the tube side
00:06:39.310 00:06:39.320 pressure drop and the shell side
00:06:41.740 00:06:41.750 pressure drop so that's a quick example
00:06:45.880 00:06:45.890 of how we can apply problems and use the
00:06:51.220 00:06:51.230 shell and tube heat exchanger calculator
00:06:53.470 00:06:53.480 at Chemical Engineering now calm

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