Lec 21 - Various types of heat exchangers for food process engineering

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Language: en

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00:00:21.940 00:00:21.950 you
00:00:29.700 00:00:29.710 good morning all so today we are going
00:00:32.310 00:00:32.320 to discuss about various types of heat
00:00:34.650 00:00:34.660 exchanger which are used in the food
00:00:36.960 00:00:36.970 process engineering our food process
00:00:39.060 00:00:39.070 industries so we go a little
00:00:42.960 00:00:42.970 introduction about the heat exchangers
00:00:45.479 00:00:45.489 and what our how to design a heat
00:00:47.790 00:00:47.800 exchanger and what are all the
00:00:50.700 00:00:50.710 applications of heat exchangers in food
00:00:53.100 00:00:53.110 process industries and main type of for
00:00:57.299 00:00:57.309 heat exchangers we are going to see in
00:00:59.369 00:00:59.379 this particular lecture so the heat
00:01:02.250 00:01:02.260 exchangers are devices for the exchange
00:01:04.649 00:01:04.659 of heat between two fluids separated by
00:01:07.289 00:01:07.299 a heat conducting partition so this is
00:01:09.810 00:01:09.820 nothing but a wall right two fluids we
00:01:14.640 00:01:14.650 have a hot fluid as well as cold fluid
00:01:17.160 00:01:17.170 so mostly cold fluid is here is your a
00:01:20.130 00:01:20.140 liquid flow food particle sometimes with
00:01:23.310 00:01:23.320 the particulate solids heat exchangers
00:01:26.190 00:01:26.200 are extensively used in the food
00:01:28.050 00:01:28.060 industry for heating which is nothing
00:01:30.480 00:01:30.490 but pass tracer and cooling chilled
00:01:33.690 00:01:33.700 water generators and heat induced phase
00:01:36.720 00:01:36.730 change so which is nothing but a
00:01:38.340 00:01:38.350 freezing and evaporation so this
00:01:40.440 00:01:40.450 evaporation we have seen in the membrane
00:01:42.420 00:01:42.430 separation as well to concentrate the
00:01:44.580 00:01:44.590 food material right so then each one of
00:01:48.330 00:01:48.340 the fluids may be confined or unconfined
00:01:51.180 00:01:51.190 stagnant or flowing so depends upon the
00:01:54.210 00:01:54.220 heat exchanger we use so each one of the
00:01:57.390 00:01:57.400 two fluids may be confined or unconfined
00:01:59.790 00:01:59.800 stagnant or flowing the partition is a
00:02:02.880 00:02:02.890 heat conducting solid Volusia Li made of
00:02:05.310 00:02:05.320 metal to give high thermal conductivity
00:02:07.520 00:02:07.530 the design of a heat exchanger usually
00:02:10.380 00:02:10.390 involves two main domains namely thermal
00:02:12.809 00:02:12.819 analysis and hydraulic calculations
00:02:15.149 00:02:15.159 because the heat exchanger the food is
00:02:17.399 00:02:17.409 liquid food right so if you remember in
00:02:19.740 00:02:19.750 our a septic processing calculations I
00:02:22.080 00:02:22.090 told the same thing because in
00:02:24.740 00:02:24.750 continuous thermal processing so we need
00:02:27.809 00:02:27.819 to take care of the hydraulic
00:02:29.759 00:02:29.769 calculations as well as the thermal
00:02:31.440 00:02:31.450 analysis heat transfer as well as fluid
00:02:33.539 00:02:33.549 flow so here is one example so this is a
00:02:38.910 00:02:38.920 solid wall these two are solid walls
00:02:41.250 00:02:41.260 right the heat is given
00:02:43.360 00:02:43.370 here in the solid wall so their
00:02:45.880 00:02:45.890 temperature here ta in the outside of
00:02:49.780 00:02:49.790 the wall
00:02:50.380 00:02:50.390 and T be in the other side of the wall
00:02:52.540 00:02:52.550 and the wall temperature is t1 and this
00:02:56.080 00:02:56.090 side it is t2 and the h1 is nothing but
00:02:59.199 00:02:59.209 a heat transfer coefficient H 2 is a
00:03:01.660 00:03:01.670 heat transfer coefficient in the other
00:03:03.520 00:03:03.530 side right so this is the ambient maybe
00:03:06.460 00:03:06.470 we can consider so this is also ambient
00:03:12.809 00:03:12.819 or you can consider here maybe another
00:03:18.220 00:03:18.230 Florida's there right so now if we want
00:03:22.660 00:03:22.670 to write Q the heat balance Q is nothing
00:03:26.500 00:03:26.510 but a ta minus TB right so flux which is
00:03:33.789 00:03:33.799 nothing but a q upon a write Q upon a is
00:03:36.640 00:03:36.650 nothing but he turns fur rate upon area
00:03:39.460 00:03:39.470 so heat transfer rate is nothing but in
00:03:41.830 00:03:41.840 watts and area is in meter square so
00:03:45.550 00:03:45.560 this part is nothing but joules per
00:03:47.319 00:03:47.329 second so that means heat transfer rate
00:03:49.660 00:03:49.670 per meter square which is nothing but a
00:03:52.000 00:03:52.010 heat flux heat flux can be written as a
00:03:55.050 00:03:55.060 thermal gradient because in heat
00:03:57.430 00:03:57.440 transfer it is a thermal gradient any
00:03:59.770 00:03:59.780 flux can be written as a gradient apart
00:04:02.830 00:04:02.840 resistance okay so in heat transfer it
00:04:06.250 00:04:06.260 is a thermal gradient the R we are going
00:04:08.770 00:04:08.780 to write so R if you see so this is the
00:04:11.380 00:04:11.390 H 1 H 1 is nothing but ER
00:04:13.750 00:04:13.760 he transfer coefficient right convective
00:04:17.289 00:04:17.299 heat transfer coefficient and this is
00:04:19.750 00:04:19.760 nothing but a solid solid material for
00:04:22.150 00:04:22.160 example this is the wall of the heat
00:04:25.300 00:04:25.310 exchanger right so this is the wall of
00:04:27.520 00:04:27.530 the heat exchanger this side one fluid
00:04:30.070 00:04:30.080 resides the other side of the wall
00:04:32.469 00:04:32.479 another fluid reside so instead of
00:04:34.600 00:04:34.610 ambient you can take an example of heat
00:04:37.870 00:04:37.880 exchanger itself right so this is the
00:04:39.969 00:04:39.979 heat exchanger wall so one fluid recites
00:04:42.640 00:04:42.650 this side another fluid recites that
00:04:44.260 00:04:44.270 side so the H one is the heat transfer
00:04:46.900 00:04:46.910 coefficient of this particular fluid da
00:04:49.000 00:04:49.010 and H two is the heat transfer
00:04:52.270 00:04:52.280 coefficient of fluid B and that
00:04:54.370 00:04:54.380 temperature T one is at the wall
00:04:57.220 00:04:57.230 near the fluidy a site t2 is the
00:04:59.140 00:04:59.150 temperature in the wall at near the
00:05:01.090 00:05:01.100 fluid B side right so that TB is a
00:05:05.640 00:05:05.650 temperature of the fluid B and T a is
00:05:08.950 00:05:08.960 the temperature of fluid a so I have
00:05:11.800 00:05:11.810 basically three resistance one on the
00:05:14.020 00:05:14.030 fluid a side another on the wall and
00:05:16.510 00:05:16.520 another on the fluid B side right so I
00:05:19.420 00:05:19.430 can combine them 1 upon H 1 because
00:05:22.090 00:05:22.100 there hates is nothing but a heat
00:05:23.680 00:05:23.690 transfer coefficient resistances one
00:05:26.080 00:05:26.090 upon conductance so then your conductive
00:05:29.080 00:05:29.090 resistance is nothing but X upon K X is
00:05:32.290 00:05:32.300 nothing but a thickness of the wall okay
00:05:36.550 00:05:36.560 so that I am taking as a X so X upon k
00:05:40.060 00:05:40.070 plus 1 upon H 2 right so this is the
00:05:43.390 00:05:43.400 resistance right so here the T is in
00:05:47.440 00:05:47.450 Kelvin right so the 1 upon H is watt per
00:05:52.120 00:05:52.130 meter square Kelvin so your excess meter
00:05:56.170 00:05:56.180 K is watt per meter Kelvin so this is 1
00:06:01.780 00:06:01.790 upon watt per meter square Kelvin so
00:06:05.320 00:06:05.330 which is nothing but K upon 1 upon if
00:06:09.730 00:06:09.740 the meter comes here it is 1 upon meter
00:06:12.400 00:06:12.410 so this also 1 upon watt per meter
00:06:14.800 00:06:14.810 square 1 upon watt per meter square
00:06:18.520 00:06:18.530 Kelvin so this goes about so which is
00:06:22.870 00:06:22.880 nothing but KK get cancelled so this
00:06:25.180 00:06:25.190 also will become watt per meter square
00:06:27.760 00:06:27.770 what per meter square you know
00:06:29.470 00:06:29.480 disconcert so I can write my Q as a a TB
00:06:35.080 00:06:35.090 minus T ta minus TB
00:06:46.290 00:06:46.300 / one upon you so this one upon you is
00:06:50.860 00:06:50.870 nothing but 1 upon H 1 + X upon K so
00:06:55.360 00:06:55.370 this is a conductive resistance this is
00:06:57.280 00:06:57.290 convective resistance plus 1 upon H 2
00:07:00.220 00:07:00.230 this is also convective resistance so if
00:07:02.560 00:07:02.570 you write Q is equal to you yet ta minus
00:07:05.770 00:07:05.780 TB is nothing but del T so U is nothing
00:07:08.920 00:07:08.930 but overall heat transfer coefficient AC
00:07:12.250 00:07:12.260 area del T is nothing but temperature
00:07:14.740 00:07:14.750 difference between the fluids T ADB and
00:07:17.260 00:07:17.270 Q is nothing but heat transfer rate so
00:07:19.840 00:07:19.850 if you remember we have done in the past
00:07:23.170 00:07:23.180 recession play a type heat exchanger
00:07:25.000 00:07:25.010 problem we have also calculated number
00:07:27.310 00:07:27.320 of plates required for the heating so if
00:07:31.060 00:07:31.070 you remember we have taken the you write
00:07:33.850 00:07:33.860 the milk side heat transfer coefficient
00:07:36.100 00:07:36.110 in heating cooling as well as the
00:07:38.920 00:07:38.930 regeneration there we have taken around
00:07:41.170 00:07:41.180 approximately thousand watt per meter
00:07:44.350 00:07:44.360 squared Kelvin so if your fluid a is
00:07:47.110 00:07:47.120 liquid and fluid B is liquid in the
00:07:49.870 00:07:49.880 plate heat exchanger type you are use
00:07:52.120 00:07:52.130 around thousand to three thousand watt
00:07:54.940 00:07:54.950 per meter squared Kelvin so that's what
00:07:57.640 00:07:57.650 it is given so based on the fluid for
00:08:00.940 00:08:00.950 example if it is a gas gas in tubular
00:08:03.280 00:08:03.290 heat exchanger so you were heat transfer
00:08:05.920 00:08:05.930 coefficient Phi 250 watt per meter
00:08:08.290 00:08:08.300 squared Kelvin so if you remember the
00:08:11.290 00:08:11.300 same pasteurization lecture I also told
00:08:14.980 00:08:14.990 in the past tracer or sterilizer you
00:08:18.220 00:08:18.230 should not keep the AR packets because
00:08:20.590 00:08:20.600 AR is a very low conductive medium so
00:08:24.130 00:08:24.140 you can see from here the liquid if you
00:08:27.190 00:08:27.200 have a fluid is a liquid fluid B as a
00:08:29.650 00:08:29.660 liquid you are overall heat transfer
00:08:31.270 00:08:31.280 coefficient is thousand around thousand
00:08:33.760 00:08:33.770 watt per meter square so if you have a
00:08:35.800 00:08:35.810 gaseous heat exchanger so your overall
00:08:38.469 00:08:38.479 coefficient is 5 250 watt per meter
00:08:40.719 00:08:40.729 squared Kelvin so if you have er packets
00:08:43.540 00:08:43.550 inside the sterilizer or the pass racing
00:08:46.930 00:08:46.940 unit so that will lead to high
00:08:49.660 00:08:49.670 temperature difference between the food
00:08:52.000 00:08:52.010 material so that leads to contamination
00:08:54.700 00:08:54.710 so this is the reason we need to avoid
00:08:56.920 00:08:56.930 yeah
00:08:57.940 00:08:57.950 in sterilizing operation okay so the
00:09:01.320 00:09:01.330 introduction in continuous heat
00:09:03.520 00:09:03.530 exchangers both the fluids are in
00:09:05.620 00:09:05.630 movement right so mostly the heat
00:09:08.470 00:09:08.480 exchanger we use for continuous flow in
00:09:11.470 00:09:11.480 continuous a heat exchanger both fluids
00:09:14.050 00:09:14.060 are in moment there are three main types
00:09:16.330 00:09:16.340 of flow patterns one is parallel counter
00:09:19.270 00:09:19.280 current and cross flow so one example
00:09:22.060 00:09:22.070 would be this one so this is a counter
00:09:25.540 00:09:25.550 current counter current your heart fluid
00:09:32.740 00:09:32.750 is coming in and going this side and
00:09:36.850 00:09:36.860 your cold fluid is coming here so and
00:09:41.280 00:09:41.290 leaving this side of the heat exchanger
00:09:46.870 00:09:46.880 so this is the counter current
00:09:48.160 00:09:48.170 co-current means your fluid hot fluid as
00:09:52.470 00:09:52.480 well as cold fluid hot fluid hot out hot
00:09:57.730 00:09:57.740 in so you are cold in and cold out it
00:10:07.090 00:10:07.100 cross flow is nothing but so you are
00:10:10.290 00:10:10.300 heart Florida and they were hot fluid
00:10:17.650 00:10:17.660 out
00:10:22.610 00:10:22.620 so this is inside the tube okay through
00:10:25.730 00:10:25.740 your cold fluid will be perpendicular to
00:10:29.389 00:10:29.399 a hard fluid direction so this is
00:10:35.720 00:10:35.730 nothing but your cross flow okay so this
00:10:41.780 00:10:41.790 is counter current flow this is
00:10:43.069 00:10:43.079 co-current flow parallel and counter
00:10:45.319 00:10:45.329 flow are most common in liquid liquid as
00:10:48.139 00:10:48.149 well as liquid to condensing vapor heat
00:10:50.809 00:10:50.819 exchange
00:10:51.530 00:10:51.540 so this condensing vapor is nothing but
00:10:53.749 00:10:53.759 you use the phase change heat to heat
00:10:57.499 00:10:57.509 the liquid for example if you take
00:11:00.340 00:11:00.350 heating the food material most of the
00:11:03.199 00:11:03.209 time we have seen heating medium as a
00:11:05.420 00:11:05.430 steam right so this is cold in cold the
00:11:09.319 00:11:09.329 fluid in and a cold fluid out so if you
00:11:14.030 00:11:14.040 see in the latent heat exchange so there
00:11:16.850 00:11:16.860 won't be any temperature difference so
00:11:18.739 00:11:18.749 this is a steam temperature hearten and
00:11:23.269 00:11:23.279 hot out okay so there won't be any
00:11:27.429 00:11:27.439 temperature difference in the steam so
00:11:30.170 00:11:30.180 it is a parallel as well as counter
00:11:33.199 00:11:33.209 current flow or most common and liquid
00:11:35.449 00:11:35.459 liquid or liquid to condensing vapor
00:11:37.730 00:11:37.740 heat exchange right and cash flow
00:11:40.309 00:11:40.319 exchange is particularly common for
00:11:42.230 00:11:42.240 heating or cooling the yeah
00:11:44.210 00:11:44.220 so that is gas gas heat exchanger we
00:11:46.369 00:11:46.379 have seen right so their grass flow is
00:11:48.410 00:11:48.420 mainly used as a result of flow the
00:11:50.960 00:11:50.970 temperature of each fluid and therefore
00:11:53.179 00:11:53.189 the temperature drop for heat transfer
00:11:55.400 00:11:55.410 may change from one point to other point
00:11:58.189 00:11:58.199 in the exchanger so this is where the
00:12:00.889 00:12:00.899 concept of log mean temperature
00:12:02.780 00:12:02.790 difference has come so L M TD so if you
00:12:06.860 00:12:06.870 remember in all the calculations we have
00:12:09.980 00:12:09.990 used Q is equal to UA Delta young all
00:12:14.269 00:12:14.279 right so this is nothing but log mean
00:12:16.730 00:12:16.740 temperature difference
00:12:27.329 00:12:27.339 so what does it mean so it means
00:12:44.690 00:12:44.700 so I'm putting this since a wall so here
00:12:48.260 00:12:48.270 is your hard floor den so here is your
00:12:55.370 00:12:55.380 hard floor doubt so cold fluid in I am
00:13:02.660 00:13:02.670 taking co-current flow and a cold flow
00:13:05.660 00:13:05.670 it out okay
00:13:11.840 00:13:11.850 so if you make it in terms of X versus
00:13:16.760 00:13:16.770 distance versus temperature so that thi
00:13:25.360 00:13:25.370 th i th walk th out so this is y n so
00:13:32.780 00:13:32.790 the this is TC in and TC out okay so if
00:13:40.610 00:13:40.620 I take a particular area so this would
00:13:47.840 00:13:47.850 give me t touch in and th out so the
00:13:55.370 00:13:55.380 same way for this particular area
00:14:07.019 00:14:07.029 TC in and TC out okay so this D had
00:14:15.179 00:14:15.189 chain minus TC in we call it as a del T
00:14:18.629 00:14:18.639 PI so this we call it as a del T me okay
00:14:24.090 00:14:24.100 so then finally the derivation of LM TD
00:14:27.360 00:14:27.370 I'm not going to do because that is not
00:14:29.610 00:14:29.620 in the syllabus of this particular
00:14:32.519 00:14:32.529 course but I would like to tell you that
00:14:34.740 00:14:34.750 if you really wanted to know in depth of
00:14:37.889 00:14:37.899 why we need to calculate logarithmic
00:14:40.230 00:14:40.240 mean temperature difference how to
00:14:41.759 00:14:41.769 derive that you may refer some of the
00:14:44.790 00:14:44.800 books given in the reference okay so the
00:14:48.420 00:14:48.430 the final the del T M how do we write
00:14:51.660 00:14:51.670 this which is nothing but del T I minus
00:14:55.350 00:14:55.360 del te so this is Inlet this is exit I
00:14:59.179 00:14:59.189 divided by lon of del T divided by Del T
00:15:04.920 00:15:04.930 so why we are taking mean temperature
00:15:07.350 00:15:07.360 difference because the throughout that
00:15:10.199 00:15:10.209 distance my delta T is varying so I
00:15:13.470 00:15:13.480 cannot take one particular delta T so if
00:15:16.350 00:15:16.360 you see here so this is the delta T here
00:15:19.579 00:15:19.589 so it is there delta T here okay so it
00:15:23.340 00:15:23.350 is varying along the length of the heat
00:15:25.199 00:15:25.209 exchanger that is the way we take mean
00:15:27.720 00:15:27.730 temperature difference logarithmic mean
00:15:29.549 00:15:29.559 temperature difference and also remember
00:15:32.579 00:15:32.589 here I have taken use constant along the
00:15:36.569 00:15:36.579 length because though my temperature is
00:15:38.639 00:15:38.649 varying my overall heat transfer
00:15:40.350 00:15:40.360 coefficient is constant so from this I
00:15:43.350 00:15:43.360 will calculate the log mean temperature
00:15:45.480 00:15:45.490 difference then substitute in the Q
00:15:47.670 00:15:47.680 formula which is nothing but you ei del
00:15:49.949 00:15:49.959 T here you can substitute u ru and Q you
00:15:54.090 00:15:54.100 will be able to know Q's nothing but for
00:15:57.110 00:15:57.120 hard fluid mass flow rate of hot fluid
00:16:00.269 00:16:00.279 CP of hot fluid and del T del T in the
00:16:05.369 00:16:05.379 sense T hatch in minus T hatch out okay
00:16:10.949 00:16:10.959 so the if you write for cold fluid it is
00:16:13.439 00:16:13.449 a mass flow rate of cold fluid CP of
00:16:16.919 00:16:16.929 cold fluid this is TC in -
00:16:19.740 00:16:19.750 TC out okay so remember one heart fluid
00:16:26.220 00:16:26.230 loses heat losses heat and cold fluid
00:16:39.480 00:16:39.490 gains the heat so this is the way we
00:16:49.680 00:16:49.690 calculate and design the heat exchanger
00:16:51.960 00:16:51.970 right so if I want to know how much heat
00:16:54.630 00:16:54.640 transfer area is needed to heat my fluid
00:16:59.670 00:16:59.680 the food or liquid food so I will get to
00:17:03.600 00:17:03.610 know from Q by u del T ya so the Delta
00:17:08.880 00:17:08.890 if I know Inlet outlet temperature if I
00:17:11.579 00:17:11.589 know flow configuration whether it is a
00:17:13.530 00:17:13.540 counter flow or cross flow or co-current
00:17:16.079 00:17:16.089 flow then I'll be able to calculate my
00:17:18.449 00:17:18.459 del T I del te and from there I will
00:17:21.120 00:17:21.130 calculate the log mean temperature and
00:17:24.540 00:17:24.550 from the log mean temperature I will be
00:17:26.850 00:17:26.860 able to calculate the area provided u is
00:17:30.990 00:17:31.000 given and Q I will be able to calculate
00:17:33.390 00:17:33.400 from mass rate of the hot fluid this is
00:17:36.000 00:17:36.010 mass rate which is nothing but in kg per
00:17:38.760 00:17:38.770 second or hour so this is kilo joules
00:17:41.580 00:17:41.590 per kg Kelvin so this is in Kelvin
00:17:45.360 00:17:45.370 so this Kelvin Kelvin gets canceled kilo
00:17:47.760 00:17:47.770 joules per hour so you if you convert
00:17:50.520 00:17:50.530 into joules kilo joules per second so
00:17:54.570 00:17:54.580 that is nothing but kilo but so what I
00:17:57.570 00:17:57.580 told you is here this is also in butts
00:18:00.780 00:18:00.790 right so unit you can calculate the Q
00:18:04.200 00:18:04.210 and substitute in the J formula so that
00:18:06.870 00:18:06.880 is the way you design the heat transfer
00:18:09.090 00:18:09.100 area for liquid to food to be heated in
00:18:12.540 00:18:12.550 the heat exchanger so then intro about
00:18:16.620 00:18:16.630 the heat exchanger why we need to study
00:18:18.810 00:18:18.820 and improvement in quality is one of the
00:18:21.810 00:18:21.820 main driving forces behind the
00:18:23.820 00:18:23.830 development of continuous heat processes
00:18:26.400 00:18:26.410 so the liquid semi-liquid products such
00:18:29.550 00:18:29.560 as milk juices and sauces
00:18:32.500 00:18:32.510 suffered from over processing in
00:18:34.840 00:18:34.850 traditional low-temperature long time of
00:18:38.110 00:18:38.120 an in container or batch processing
00:18:40.810 00:18:40.820 batch processing in one of the lectures
00:18:43.060 00:18:43.070 also we have discussed an Armas Li so I
00:18:45.610 00:18:45.620 just to put it and forget it for example
00:18:47.650 00:18:47.660 if you see the temperature for the
00:18:51.340 00:18:51.350 pasteurization 63 degree centigrade
00:18:54.310 00:18:54.320 about 30 minutes so this causes the
00:18:57.130 00:18:57.140 lower processing so due to which the
00:19:00.280 00:19:00.290 continuous process came into existence
00:19:02.950 00:19:02.960 so caramelized two flavors poor color
00:19:05.770 00:19:05.780 retention and a lack of a reproducible
00:19:08.919 00:19:08.929 product where all the problems
00:19:10.659 00:19:10.669 associated with the products processed
00:19:13.450 00:19:13.460 by batch method so to overcome these
00:19:16.500 00:19:16.510 disadvantages then to keep product
00:19:20.169 00:19:20.179 safety in mind the continuous processing
00:19:23.409 00:19:23.419 approaches were developed the
00:19:26.049 00:19:26.059 achievement of safe products by a
00:19:28.030 00:19:28.040 thermal processing is based upon the
00:19:30.190 00:19:30.200 theory behind the destruction of
00:19:31.980 00:19:31.990 microorganisms so why we are thermal
00:19:34.510 00:19:34.520 processing it the for the reason for
00:19:37.020 00:19:37.030 destruction of microorganisms the
00:19:39.820 00:19:39.830 products must be heated to a set
00:19:42.340 00:19:42.350 temperature for a set time in order to
00:19:44.770 00:19:44.780 achieve a commercially sterile product
00:19:47.230 00:19:47.240 in continuous heat processing also
00:19:49.900 00:19:49.910 called continuous flow processing the
00:19:52.390 00:19:52.400 product is thermally processed before
00:19:54.520 00:19:54.530 being placed into an appropriate
00:19:56.799 00:19:56.809 container on a continuous basis through
00:19:59.950 00:19:59.960 a heat exchanging plant so the main part
00:20:02.590 00:20:02.600 of the continuous thermal processing is
00:20:05.350 00:20:05.360 nothing but a heat exchanger okay so the
00:20:11.799 00:20:11.809 heat exchanger paratus will be used to
00:20:13.840 00:20:13.850 for both heating as well as cooling
00:20:16.200 00:20:16.210 cooling phase of the process this we
00:20:19.330 00:20:19.340 discussed in our earlier lectures itself
00:20:21.820 00:20:21.830 so heating as well as cooling and in few
00:20:24.730 00:20:24.740 see in the aseptic process regeneration
00:20:27.070 00:20:27.080 also in between heating regeneration and
00:20:29.950 00:20:29.960 cooling in continuous system the foots
00:20:33.070 00:20:33.080 under consideration are liquid or
00:20:35.320 00:20:35.330 semi-liquid products which may be pumped
00:20:38.440 00:20:38.450 through a system heated and cooled while
00:20:41.230 00:20:41.240 continuously flowing down the process
00:20:43.299 00:20:43.309 line a wide range of prod
00:20:45.670 00:20:45.680 so I processed by this method that means
00:20:47.860 00:20:47.870 the continuous flow process either a
00:20:50.020 00:20:50.030 main process to achieve a safe product
00:20:52.480 00:20:52.490 the main process itself a heat
00:20:55.000 00:20:55.010 exchanging process which is nothing but
00:20:56.980 00:20:56.990 ultra heat treated or ultra high
00:20:59.080 00:20:59.090 temperature are a step with enough
00:21:01.810 00:21:01.820 further processing the heat exchanger
00:21:03.940 00:21:03.950 may be used as an intermediate step to
00:21:06.760 00:21:06.770 heat the fluid or the main process
00:21:09.490 00:21:09.500 itself a heat exchanging process which
00:21:11.680 00:21:11.690 is happening in the ultra high
00:21:13.330 00:21:13.340 temperature or even aseptic processing
00:21:15.610 00:21:15.620 the three main types of process are
00:21:18.430 00:21:18.440 suitable for continuous flow processing
00:21:20.740 00:21:20.750 or a septic systems which is high and
00:21:23.410 00:21:23.420 low acid foot and heart fill systems
00:21:25.980 00:21:25.990 pasteurization process so everything
00:21:28.660 00:21:28.670 comes under this continuous flow process
00:21:31.270 00:21:31.280 category aseptically pact products or
00:21:34.750 00:21:34.760 process two temperatures that will
00:21:36.730 00:21:36.740 render the product commercially sterile
00:21:39.340 00:21:39.350 so aseptic processing we have already
00:21:41.560 00:21:41.570 seen in maybe three lectures I guess so
00:21:46.300 00:21:46.310 then heating applications so this also
00:21:48.940 00:21:48.950 we have discussed if it is a high acid
00:21:51.280 00:21:51.290 products such as juice can be processed
00:21:54.610 00:21:54.620 at pasteurization temperature to destroy
00:21:56.830 00:21:56.840 the microorganism that can cost the
00:21:59.140 00:21:59.150 spoilage of the product there are then
00:22:01.420 00:22:01.430 rapidly cool to reduce the loss of
00:22:03.880 00:22:03.890 volatiles within the product also to
00:22:06.400 00:22:06.410 reduce the contamination of thermo
00:22:09.280 00:22:09.290 philic bacterias right because when you
00:22:11.980 00:22:11.990 slowly cooling there may be a chance for
00:22:14.860 00:22:14.870 the Bri contamination so the cooling is
00:22:17.650 00:22:17.660 done very rapidly and filled into a
00:22:21.000 00:22:21.010 pre-sterilized pack under sterile
00:22:23.350 00:22:23.360 conditions so hot acid products we do
00:22:25.930 00:22:25.940 pasteurization and a packet under
00:22:28.270 00:22:28.280 sterile conditions in a sterilized
00:22:30.340 00:22:30.350 packaging the low acid products which
00:22:33.010 00:22:33.020 undergo same principle however the
00:22:35.020 00:22:35.030 temperature employed are much higher to
00:22:37.450 00:22:37.460 and should no survival of the pathogenic
00:22:40.270 00:22:40.280 bacteria so that's why we go for a
00:22:42.610 00:22:42.620 sterilization the temperature applied
00:22:44.950 00:22:44.960 here at 125 to 145 degree so allowing
00:22:48.610 00:22:48.620 for much shorter holding times and
00:22:50.890 00:22:50.900 promoting a higher quality product the
00:22:53.860 00:22:53.870 continuous flow processing system can
00:22:55.900 00:22:55.910 also be used in a heartful processes for
00:22:59.049 00:22:59.059 high acid products again heart fill
00:23:00.940 00:23:00.950 processes r5 high acid products that
00:23:03.789 00:23:03.799 would otherwise lose product quality
00:23:05.860 00:23:05.870 through slow cooling methods and high
00:23:10.629 00:23:10.639 acid choices again high acid food comes
00:23:13.570 00:23:13.580 under pasteurization category they are
00:23:15.789 00:23:15.799 filling directly into suitable
00:23:17.590 00:23:17.600 containers using the heat of the product
00:23:20.289 00:23:20.299 to decontaminate the packaging so
00:23:23.049 00:23:23.059 sometimes this also tried so this method
00:23:25.600 00:23:25.610 is this method allows a much quicker
00:23:28.299 00:23:28.309 throughput than a typical batch process
00:23:31.600 00:23:31.610 would offer the high acid cetain high
00:23:34.419 00:23:34.429 acid foots path traced and filled in the
00:23:37.779 00:23:37.789 normal containers not in a sterile
00:23:39.940 00:23:39.950 containers so the product heat itself
00:23:42.399 00:23:42.409 further decontaminate the packaging so
00:23:44.980 00:23:44.990 this also another heating applications
00:23:46.989 00:23:46.999 where heat exchanging systems are used
00:23:48.999 00:23:49.009 and pasteurization of low acid products
00:23:51.850 00:23:51.860 that will then be cooled and held under
00:23:54.159 00:23:54.169 chill the conditions so this is where we
00:23:56.200 00:23:56.210 don't so we need to refrigerate them
00:23:58.989 00:23:58.999 even low acid products so pasteurized
00:24:01.359 00:24:01.369 milk juices soups everything comes under
00:24:04.119 00:24:04.129 this category this processing step
00:24:06.519 00:24:06.529 extends the shelf life and ensures the
00:24:09.460 00:24:09.470 safe product the product must be chilled
00:24:12.279 00:24:12.289 to maintain its safety and quality
00:24:14.200 00:24:14.210 throughout the shelf life shelve lives
00:24:16.570 00:24:16.580 up to ten days can be achieved for some
00:24:19.210 00:24:19.220 products so these are all some of the
00:24:21.249 00:24:21.259 heating up applications furnace high
00:24:23.169 00:24:23.179 acid products which are pasteurized and
00:24:26.009 00:24:26.019 part-owner sterilized to packaging under
00:24:28.600 00:24:28.610 sterile condition low acid products
00:24:30.669 00:24:30.679 which are to be sterilized to kill the
00:24:33.070 00:24:33.080 pathogenic bacteria and heartful
00:24:35.739 00:24:35.749 processes where high acid products are
00:24:38.109 00:24:38.119 processed and these high acid products
00:24:41.950 00:24:41.960 are processed and filled in the
00:24:43.690 00:24:43.700 packaging so that temperature of the
00:24:45.970 00:24:45.980 products itself will take care of the
00:24:48.210 00:24:48.220 decontamination of the packaging system
00:24:50.710 00:24:50.720 then further pasteurization of low acid
00:24:53.799 00:24:53.809 products here we did sterilization so if
00:24:56.619 00:24:56.629 you do pasteurization that has to be
00:24:58.539 00:24:58.549 chilled to extend the further shelf life
00:25:01.889 00:25:01.899 okay so although heating vessels are
00:25:04.899 00:25:04.909 cooking kettles by definition heat
00:25:07.509 00:25:07.519 exchanges so whatever we use in
00:25:09.519 00:25:09.529 day-to-day life those also called as a
00:25:11.889 00:25:11.899 heat
00:25:12.400 00:25:12.410 changer because the heat exchanger is
00:25:14.320 00:25:14.330 one which exceeds the heat right through
00:25:17.110 00:25:17.120 a solid one they themself cooking
00:25:19.420 00:25:19.430 kettles themself as a heat exchanger
00:25:21.790 00:25:21.800 even one of the lecture I mentioned
00:25:23.520 00:25:23.530 whatever we do in normal day-to-day
00:25:26.140 00:25:26.150 process which is nothing but a
00:25:28.120 00:25:28.130 pasteurization of milk so whenever we
00:25:30.370 00:25:30.380 are heating the milk we are doing
00:25:32.110 00:25:32.120 pasteurization but that is not the case
00:25:34.360 00:25:34.370 with the industry they have to handle
00:25:36.730 00:25:36.740 the large volume and they have supposed
00:25:38.740 00:25:38.750 to store and distribute for further use
00:25:41.440 00:25:41.450 so in that case GMP regulations were to
00:25:44.200 00:25:44.210 be followed right good manufacturing
00:25:46.120 00:25:46.130 practices to be followed here also the
00:25:50.320 00:25:50.330 heat exchangers cooking kettles also by
00:25:53.110 00:25:53.120 definition heat exchangers but the only
00:25:56.500 00:25:56.510 continuous inflow heat exchangers which
00:25:59.170 00:25:59.180 are used in the food processing industry
00:26:00.960 00:26:00.970 which we will be discussed in this
00:26:03.760 00:26:03.770 lecture because of strict sanitary
00:26:06.490 00:26:06.500 requirements right so only a few of the
00:26:09.700 00:26:09.710 many heat exchanger types utilized in
00:26:12.190 00:26:12.200 the process industry are suitable for
00:26:14.440 00:26:14.450 food applications so the same thing I'll
00:26:17.950 00:26:17.960 be telling in the dryers as well so we
00:26:21.820 00:26:21.830 are also going to have a lectures on dry
00:26:23.860 00:26:23.870 as various andreas used in the food
00:26:26.080 00:26:26.090 processing industry there there are lot
00:26:28.600 00:26:28.610 of dryers are there and even normal
00:26:30.970 00:26:30.980 chemical industry also uses various
00:26:33.160 00:26:33.170 dryers but these dryers which are used
00:26:37.510 00:26:37.520 in food industry should be hygienic
00:26:39.700 00:26:39.710 right the dehydration plant should be
00:26:41.920 00:26:41.930 contamination free for for the dryers to
00:26:46.180 00:26:46.190 be used in the food industry the same
00:26:48.100 00:26:48.110 thing here even though there are lot
00:26:50.110 00:26:50.120 many varieties of heat exchangers are
00:26:52.300 00:26:52.310 available in the processing industries
00:26:54.220 00:26:54.230 but food processing industry strictly
00:26:56.830 00:26:56.840 follows the sanitary requirements so
00:26:59.230 00:26:59.240 because of which very few types of heat
00:27:01.750 00:27:01.760 exchangers are used
00:27:03.420 00:27:03.430 the first one is tubular heat exchanger
00:27:06.340 00:27:06.350 the simplest representative of this
00:27:08.740 00:27:08.750 group consists of a pair of
00:27:10.590 00:27:10.600 concentrating tubes for ease of cleaning
00:27:13.810 00:27:13.820 the food product usually flows in the
00:27:16.390 00:27:16.400 inner tube and the heating or cooling
00:27:18.430 00:27:18.440 medium in the outer annular space there
00:27:21.520 00:27:21.530 variation of this type is the triple
00:27:23.860 00:27:23.870 tube right so which
00:27:26.019 00:27:26.029 has three tubes as a concentric tube in
00:27:29.169 00:27:29.179 the middle tube your product would be
00:27:31.539 00:27:31.549 flowing the other two inner and outer
00:27:34.180 00:27:34.190 tube your heating and cooling medium if
00:27:36.310 00:27:36.320 it is a heating process it is a heating
00:27:38.859 00:27:38.869 medium if it is a cooling process it is
00:27:40.690 00:27:40.700 a cooling medium the product is fed into
00:27:42.909 00:27:42.919 the middle tube and the heating or
00:27:45.129 00:27:45.139 cooling medium to the inner and outer
00:27:47.049 00:27:47.059 tube which provides the heat transfer
00:27:49.330 00:27:49.340 areas on both side of the middle tube so
00:27:51.969 00:27:51.979 if you have a tube in concentric double
00:27:56.560 00:27:56.570 pipe heat exchanger so you will have the
00:27:59.829 00:27:59.839 hard fluid flowing in here so if you
00:28:03.489 00:28:03.499 have one more tube
00:28:05.139 00:28:05.149 so probably we will see in the here the
00:28:07.570 00:28:07.580 water Steuben tube as well as tube in
00:28:10.149 00:28:10.159 tube in tube heat exchanger first we
00:28:12.459 00:28:12.469 will see the theory so the product is
00:28:14.799 00:28:14.809 fed to the middle tube and that heating
00:28:16.989 00:28:16.999 and cooling medium to the inner and
00:28:18.729 00:28:18.739 outer tube thus providing heat transfer
00:28:20.950 00:28:20.960 areas on both side of the middle tube
00:28:23.139 00:28:23.149 the calculation of overall heat transfer
00:28:25.149 00:28:25.159 coefficient for this type of equipment
00:28:27.459 00:28:27.469 is more complex so whatever I told here
00:28:30.190 00:28:30.200 so here fluid is flowing other side of
00:28:32.680 00:28:32.690 the wall one heat exchanger wall is
00:28:34.839 00:28:34.849 there one fluid is flowing this side
00:28:36.519 00:28:36.529 another fluid is flowing this side so
00:28:38.499 00:28:38.509 that is the way we calculated the
00:28:39.999 00:28:40.009 overall heat transfer coefficient but if
00:28:42.129 00:28:42.139 you have a three tubes then you need to
00:28:44.440 00:28:44.450 further calculate the heat transfer
00:28:46.269 00:28:46.279 coefficient that is not that easy or
00:28:48.940 00:28:48.950 straightforward method to calculate the
00:28:51.209 00:28:51.219 overall heat transfer coefficient for
00:28:53.469 00:28:53.479 the triple tube heat exchanger than the
00:28:56.589 00:28:56.599 double tube heat exchanger so the next
00:28:59.379 00:28:59.389 one is shell and tube the tubular heat
00:29:01.599 00:29:01.609 exchanger consists of a bundles of
00:29:03.879 00:29:03.889 parallel tubes inside a larger
00:29:06.219 00:29:06.229 cylindrical jacket again the product is
00:29:09.070 00:29:09.080 fed into the tube side so in your type
00:29:11.889 00:29:11.899 of tubular exchanger known as a Joule
00:29:14.320 00:29:14.330 effect heater the tube wall is
00:29:16.690 00:29:16.700 electrically heated so it is not to be
00:29:19.389 00:29:19.399 necessarily the cold fluid will be
00:29:21.549 00:29:21.559 heated through the hot fluid so here in
00:29:25.389 00:29:25.399 the certain type of tubular exchanger
00:29:28.180 00:29:28.190 which is called as a Joule effect heater
00:29:30.519 00:29:30.529 the tube wall is founded with the
00:29:32.289 00:29:32.299 electrical coils they can be heated
00:29:35.229 00:29:35.239 electrically as well the tubular heat
00:29:37.899 00:29:37.909 exchangers are particularly so
00:29:39.730 00:29:39.740 trouble for heating or cooling highly
00:29:41.980 00:29:41.990 viscous products we're relatively high
00:29:44.890 00:29:44.900 pressures must be applied or therefore
00:29:47.740 00:29:47.750 heat relized foreign bulk inflow
00:29:49.870 00:29:49.880 sterilization of the products containing
00:29:52.210 00:29:52.220 solid particles and for the heat
00:29:54.790 00:29:54.800 treatment of cooling of tomato paste
00:29:57.220 00:29:57.230 prior to aseptic processing so these are
00:30:01.000 00:30:01.010 used to fer bulk inflow sterilization of
00:30:03.790 00:30:03.800 the products which has certain solid
00:30:06.160 00:30:06.170 particles as well are for the heat
00:30:08.440 00:30:08.450 00:30:10.600 00:30:10.610 prayer to aseptic processing so that
00:30:13.450 00:30:13.460 means high viscous high viscous liquid
00:30:18.669 00:30:18.679 for hot so they can also be used with
00:30:24.070 00:30:24.080 the liquid food with the solid particles
00:30:30.480 00:30:30.490 food with solid particles so the tubular
00:30:39.549 00:30:39.559 heat exchanger are also the heat
00:30:41.890 00:30:41.900 transfer component in a tubular
00:30:43.870 00:30:43.880 evaporators so here is what your double
00:30:48.280 00:30:48.290 pipe heat exchanger so which is nothing
00:30:50.080 00:30:50.090 but a tubular heat exchanger so your
00:30:52.480 00:30:52.490 heart fluid goes in here are you can say
00:30:57.160 00:30:57.170 your liquid food material is inside the
00:30:59.620 00:30:59.630 tube liquid food so your heat medium or
00:31:05.919 00:31:05.929 heating medium in terms of heating or
00:31:08.169 00:31:08.179 cooling medium in terms of cooling flows
00:31:11.380 00:31:11.390 this side she think not cooling medium
00:31:19.560 00:31:19.570 okay so this is the shell and tube shall
00:31:24.340 00:31:24.350 earn you
00:31:30.380 00:31:30.390 this is the shell and tube heat
00:31:32.490 00:31:32.500 exchanger where number of tubes so if
00:31:35.490 00:31:35.500 you see number of tubes are put together
00:31:37.590 00:31:37.600 in a bundle so then the shell side your
00:31:41.810 00:31:41.820 normal heating or cooling medium will be
00:31:44.520 00:31:44.530 flowing so this is heating or cooling
00:31:47.310 00:31:47.320 medium heating or cooling medium so this
00:31:57.120 00:31:57.130 is heating
00:32:02.780 00:32:02.790 or cooling medium so inside that you've
00:32:09.870 00:32:09.880 your food material is flowing so this is
00:32:12.900 00:32:12.910 where in the industry where tubular heat
00:32:15.690 00:32:15.700 exchanger looks like right and one more
00:32:18.900 00:32:18.910 thing what we have seen is the triple
00:32:21.390 00:32:21.400 pipe right so triple pipe is something
00:32:24.240 00:32:24.250 like this right so we told so the inner
00:32:31.050 00:32:31.060 pipe as well as the outer pipe right so
00:32:34.530 00:32:34.540 in the both places you are heating or
00:32:38.190 00:32:38.200 cooling medium is flowing in the middle
00:32:47.730 00:32:47.740 of the pipe right in the middle pipe so
00:32:51.630 00:32:51.640 your flow a liquid fluid is flowing
00:32:55.640 00:32:55.650 liquid foodless know so this is tube in
00:33:02.160 00:33:02.170 tube in tube heat exchanger so this is
00:33:06.540 00:33:06.550 shell-and-tube this is tubular exchanger
00:33:09.210 00:33:09.220 which has two concentric tubes so this
00:33:12.750 00:33:12.760 is scrap the surface so we will see
00:33:14.970 00:33:14.980 about the theory and come back so this
00:33:18.090 00:33:18.100 is a clay right like shell and tube as
00:33:20.490 00:33:20.500 well as tubular exchanger this is the
00:33:22.260 00:33:22.270 basic types so in the tube your liquid
00:33:25.440 00:33:25.450 food material is going so other tubes
00:33:27.780 00:33:27.790 you are our tube our shell side you are
00:33:30.270 00:33:30.280 heating or cooling medium is flowing so
00:33:33.180 00:33:33.190 it is not necessary I need to heat or
00:33:35.910 00:33:35.920 cold my liquid food with the hot fluid
00:33:39.660 00:33:39.670 or cold fluid so there may be
00:33:41.790 00:33:41.800 electrically rounded tubular exchanger
00:33:44.070 00:33:44.080 also there so in that case it is called
00:33:46.200 00:33:46.210 as Joule effect heater and these shell
00:33:50.370 00:33:50.380 and tube heat exchangers are used or
00:33:53.340 00:33:53.350 tubular heat exchangers are used to for
00:33:55.700 00:33:55.710 liquid food which contain solid
00:33:58.320 00:33:58.330 particles as well as the high viscous
00:34:01.950 00:34:01.960 liquid food also can be handled in the
00:34:04.400 00:34:04.410 tubular heat exchangers so the scrap the
00:34:08.010 00:34:08.020 surface heat exchangers so which has a
00:34:10.290 00:34:10.300 they consist of a jacketed cylinder a
00:34:12.840 00:34:12.850 cooped with the central
00:34:14.370 00:34:14.380 dating - sure with scrapping blades so
00:34:17.010 00:34:17.020 that is right here so this is your
00:34:19.050 00:34:19.060 jacket so in the middle you have a rotor
00:34:24.030 00:34:24.040 right so the rotor has blades so this is
00:34:27.180 00:34:27.190 the side view so this is blades so this
00:34:30.630 00:34:30.640 is a rotor so this at this place
00:34:34.560 00:34:34.570 you are liquid food with the high amount
00:34:38.160 00:34:38.170 of solid particles stays there okay so
00:34:42.780 00:34:42.790 they consist of a jacketed cylinder
00:34:45.060 00:34:45.070 equipped with the central rotating -
00:34:47.160 00:34:47.170 sure with scrapping blades so they can
00:34:49.530 00:34:49.540 be horizontal or vertical the product is
00:34:52.500 00:34:52.510 fed into the cylinder they rapidly
00:34:55.080 00:34:55.090 rotating the rotating speed is about 600
00:34:58.650 00:34:58.660 to 700 rpm and they spread scraps and
00:35:03.030 00:35:03.040 moves the product as a flim over the
00:35:06.000 00:35:06.010 wall the heating or cooling medium is
00:35:08.610 00:35:08.620 fed into the jacket so here you have
00:35:11.520 00:35:11.530 your heating or cooling medium so these
00:35:14.160 00:35:14.170 rotors helping the products because it
00:35:17.190 00:35:17.200 has high amount of solids because the
00:35:20.690 00:35:20.700 scraplet surface heat exchanger is
00:35:23.070 00:35:23.080 mainly used to for high viscous fluids
00:35:25.650 00:35:25.660 or liquid food contains a large amount
00:35:28.860 00:35:28.870 of solid particulates so for this
00:35:30.980 00:35:30.990 application only this crapola surface
00:35:34.110 00:35:34.120 heat exchangers are used so in that case
00:35:36.990 00:35:37.000 so this blades are helping the solids
00:35:41.010 00:35:41.020 liquid food with the high amount of
00:35:44.160 00:35:44.170 solids to form a film layer near the
00:35:46.940 00:35:46.950 jacketed one in the other side of the
00:35:50.010 00:35:50.020 jacketed one you are heating our cooling
00:35:52.350 00:35:52.360 medium is flowing so the scrap surface
00:35:55.830 00:35:55.840 heat exchangers are used to for heating
00:35:57.990 00:35:58.000 cooling highly viscous fluids and for
00:36:00.930 00:36:00.940 slush freezing the continuous ice cream
00:36:04.200 00:36:04.210 freezes and slush freezes or essentially
00:36:07.800 00:36:07.810 scrap the surface heat exchanges with
00:36:10.530 00:36:10.540 the refrigerant evaporating in the
00:36:12.600 00:36:12.610 jacket so one thing is as I said earlier
00:36:15.960 00:36:15.970 it need not be always hard fluid or cold
00:36:18.960 00:36:18.970 fluid here the refrigerant is also used
00:36:21.570 00:36:21.580 as a heating or cooling medium because
00:36:24.750 00:36:24.760 it gets evaporated the less tempering
00:36:32.140 00:36:32.150 okay so the scrapple exchanger is an
00:36:35.690 00:36:35.700 expensive piece of equipment both in
00:36:38.120 00:36:38.130 price as well as in operating cost
00:36:40.340 00:36:40.350 because it has got many moving parts so
00:36:43.340 00:36:43.350 the exchanges are expensive so the next
00:36:46.490 00:36:46.500 one is very important heat exchangers in
00:36:49.430 00:36:49.440 the food industry so it is almost came
00:36:51.890 00:36:51.900 into existence in 1923 and in most of
00:36:55.340 00:36:55.350 the pass tracing or a aseptic processing
00:36:57.680 00:36:57.690 the plate type heat exchangers are used
00:37:00.260 00:37:00.270 so the plate type heat exchangers are
00:37:03.200 00:37:03.210 well established method for processing
00:37:05.930 00:37:05.940 homogeneous products of low viscosity
00:37:08.320 00:37:08.330 making them ideal for use within Diaries
00:37:12.430 00:37:12.440 mostly in the past recession or aseptic
00:37:15.410 00:37:15.420 processing of milk the plate heat
00:37:17.980 00:37:17.990 exchangers consist of a series of plates
00:37:20.690 00:37:20.700 connected on a frame the product and
00:37:23.780 00:37:23.790 heating or cooling media flow in
00:37:26.690 00:37:26.700 alternate channels in thin layers to
00:37:29.720 00:37:29.730 provide good heat transfer conditions so
00:37:32.359 00:37:32.369 I have a plates eight one side my heart
00:37:36.410 00:37:36.420 fluid is flowing other side cold fluid
00:37:38.960 00:37:38.970 other side hot fluid other side cold
00:37:41.240 00:37:41.250 fluid so this is the way the alternative
00:37:43.490 00:37:43.500 channels are arranged the plates are
00:37:45.920 00:37:45.930 sealed by elastic sealing gasket
00:37:48.609 00:37:48.619 cemented into a perforated gru right so
00:37:52.609 00:37:52.619 generally the plates are of polished
00:37:54.920 00:37:54.930 stainless steel which is of about 0.5 to
00:37:58.550 00:37:58.560 1 point to 5 mm in thickness separated
00:38:01.970 00:38:01.980 by 3 to 6 mm right
00:38:04.609 00:38:04.619 so these plates of are of stainless
00:38:07.280 00:38:07.290 steel the thickness of them is 0.5 to
00:38:10.010 00:38:10.020 1.25 mm they are separated by the
00:38:12.740 00:38:12.750 distance 3 to 6 mm okay so in these
00:38:16.640 00:38:16.650 plates are separated by 3 to 6 mm and
00:38:19.880 00:38:19.890 they are sealed by elastic sealing
00:38:21.980 00:38:21.990 gasket cemented into a perforated groove
00:38:24.830 00:38:24.840 so this we will see in picture so the
00:38:27.920 00:38:27.930 surface of the plates is usually
00:38:30.050 00:38:30.060 corrugated in order to increase the area
00:38:32.870 00:38:32.880 available for heat transfer as well as
00:38:35.480 00:38:35.490 enhance the turbulence present in the
00:38:38.060 00:38:38.070 system resulting in a high thermal
00:38:40.910 00:38:40.920 efficiency so these are corrugated to
00:38:43.880 00:38:43.890 promote mainly the turbulence and also
00:38:48.080 00:38:48.090 sometimes it also gives the strength to
00:38:50.840 00:38:50.850 the plates which are stacked together
00:38:57.580 00:38:57.590 okay so the thermal regeneration can in
00:39:01.100 00:39:01.110 the plate type exchanges as we have seen
00:39:03.800 00:39:03.810 in many of our lectures the thermal
00:39:06.230 00:39:06.240 regeneration as possible which can lower
00:39:08.660 00:39:08.670 the energy cost substantially then
00:39:11.240 00:39:11.250 narrow gaps mean that the units are best
00:39:14.420 00:39:14.430 suited for low viscosity homogeneous
00:39:17.270 00:39:17.280 products because the gaps between the
00:39:19.850 00:39:19.860 plates are very very narrow so we cannot
00:39:23.090 00:39:23.100 handle the liquid food with the large
00:39:26.000 00:39:26.010 amount of particulate solids because it
00:39:28.760 00:39:28.770 gets in between the plates and further
00:39:31.370 00:39:31.380 fouling can occur so attempts to process
00:39:34.310 00:39:34.320 particulate products which is example is
00:39:36.890 00:39:36.900 nothing but the fruit juices with the
00:39:38.840 00:39:38.850 pulp right that cells may result in
00:39:41.390 00:39:41.400 black two channels and eventually blown
00:39:44.000 00:39:44.010 plates due to the pressure imbalance
00:39:45.830 00:39:45.840 between the product and the media sites
00:39:48.530 00:39:48.540 of the plates so for this reason only
00:39:51.500 00:39:51.510 products with less than 10 percentage
00:39:53.690 00:39:53.700 particulate content or normally
00:39:55.700 00:39:55.710 recommended when processing with plate
00:39:58.100 00:39:58.110 type heat exchanger so this has to be
00:40:00.500 00:40:00.510 kept in mind so we cannot process the
00:40:03.050 00:40:03.060 liquid foot with more than 10 percentage
00:40:06.110 00:40:06.120 of the particulate content and the
00:40:08.420 00:40:08.430 regeneration is possible in plate type
00:40:11.150 00:40:11.160 heat exchangers which lowers the energy
00:40:13.580 00:40:13.590 cost and there are many variations of
00:40:16.460 00:40:16.470 the plate type heat exchanger so how to
00:40:18.770 00:40:18.780 take care of each and every plate and
00:40:21.500 00:40:21.510 which type of gross should be there and
00:40:23.720 00:40:23.730 based on the product we can select them
00:40:26.120 00:40:26.130 so which way we want the plate type heat
00:40:28.790 00:40:28.800 exchanger to be designed so here we see
00:40:31.750 00:40:31.760 so this is the plate type heat
00:40:34.550 00:40:34.560 exchangers looks like so this is your
00:40:36.590 00:40:36.600 upper bar so this is the head plate head
00:40:40.460 00:40:40.470 plate in the sense header and this is
00:40:42.530 00:40:42.540 the fall over right so in between the
00:40:44.840 00:40:44.850 header and follower your plates were
00:40:46.850 00:40:46.860 arranged so as I said so here your hot
00:40:50.510 00:40:50.520 fluid is flowing and hear your heart
00:40:52.910 00:40:52.920 fluid is flowing here you are
00:40:54.710 00:40:54.720 a hot fluid is flowing so there is a
00:40:56.390 00:40:56.400 mechanism which transfers this hard
00:40:59.240 00:40:59.250 fluid to here and so here your cold
00:41:02.210 00:41:02.220 fluid is flowing right so that means so
00:41:06.670 00:41:06.680 this flows through the plate okay so
00:41:10.460 00:41:10.470 this is the lower but this is upper but
00:41:13.069 00:41:13.079 so in which there are two mechanism
00:41:16.010 00:41:16.020 oneness the plates you can remove via
00:41:19.940 00:41:19.950 bars or it can be hanged in the bar so
00:41:23.240 00:41:23.250 if it is hanged in the bar it can be
00:41:25.190 00:41:25.200 easily taken out because one of the
00:41:28.490 00:41:28.500 advantage for this plate type heat
00:41:30.470 00:41:30.480 exchanger is this is a module type right
00:41:32.660 00:41:32.670 so in future if I want to increase the
00:41:35.750 00:41:35.760 protection so I can just add one more
00:41:38.150 00:41:38.160 module in the plate type heat exchanger
00:41:39.920 00:41:39.930 so in that way the module can be easily
00:41:42.410 00:41:42.420 added or removed based on the need of
00:41:45.260 00:41:45.270 the process industry so that is the way
00:41:47.329 00:41:47.339 we have seen right number of plates
00:41:48.980 00:41:48.990 requirement right so for regeneration
00:41:51.230 00:41:51.240 section how many number of plates are
00:41:53.170 00:41:53.180 heating section how many number of
00:41:55.190 00:41:55.200 plates on cooling section how many
00:41:56.960 00:41:56.970 number of plates so we have estimated as
00:41:59.750 00:41:59.760 a number of plates in the each section
00:42:02.660 00:42:02.670 so in that way the plates can be hanged
00:42:05.180 00:42:05.190 or the plates can be welded in the bar
00:42:08.359 00:42:08.369 so that it can be removed in the later
00:42:10.970 00:42:10.980 stage but hanging would give me
00:42:13.180 00:42:13.190 advantage if I want to remove our are
00:42:16.010 00:42:16.020 the plates and so this is the plate
00:42:18.290 00:42:18.300 package and this bolts so this will come
00:42:21.859 00:42:21.869 here so to stack the plates right it to
00:42:26.000 00:42:26.010 keep them intact between the header and
00:42:29.000 00:42:29.010 follower so these are various categories
00:42:32.240 00:42:32.250 of plate configuration so this
00:42:34.670 00:42:34.680 configuration is washboard so this is
00:42:36.980 00:42:36.990 zigzag and this is sevran or herringbone
00:42:40.550 00:42:40.560 the C type there are D typists
00:42:42.980 00:42:42.990 protrusions and depressions and e type
00:42:46.220 00:42:46.230 is washboard with secondary corrugations
00:42:48.710 00:42:48.720 and F is oblique washboard there are
00:42:52.480 00:42:52.490 different varieties right so that's what
00:42:55.370 00:42:55.380 I told so when the fluid is passing
00:42:56.990 00:42:57.000 through so it is designed in such a way
00:42:59.690 00:42:59.700 to increase the heat transfer and to
00:43:04.160 00:43:04.170 give further turbulence
00:43:07.680 00:43:07.690 - the turbo lends to the fluid okay so
00:43:16.269 00:43:16.279 that is the way it increases the heat
00:43:18.309 00:43:18.319 transfer and if you compare your
00:43:21.219 00:43:21.229 shell-and-tube module and plate module
00:43:23.709 00:43:23.719 this is the way it looks like so in that
00:43:25.569 00:43:25.579 way it is very compact compared to shell
00:43:29.499 00:43:29.509 and tube heat exchanger so the advantage
00:43:32.529 00:43:32.539 wise the capacity can be increased or
00:43:35.079 00:43:35.089 decreased by adding or removing plates
00:43:37.539 00:43:37.549 this I already discussed so that
00:43:39.999 00:43:40.009 flexibility I have in the plate type
00:43:42.160 00:43:42.170 heat exchanger the sanitation by opening
00:43:45.009 00:43:45.019 the stack both sides of the entire
00:43:47.289 00:43:47.299 exchange area are made accessible for
00:43:49.690 00:43:49.700 cleaning and inspection so it is just
00:43:51.910 00:43:51.920 the plate right in the plate the fluid
00:43:54.009 00:43:54.019 is flowing so I can remove the plate
00:43:55.959 00:43:55.969 very easily and clean them and inspect
00:43:58.569 00:43:58.579 them when needed right so the sanitation
00:44:01.479 00:44:01.489 wise it is very much advantageous and
00:44:03.579 00:44:03.589 high heat transfer coefficient due to
00:44:05.859 00:44:05.869 increase the turbulence in the narrow
00:44:07.779 00:44:07.789 flow channel that's the way the
00:44:10.029 00:44:10.039 corrugations were made and a compact
00:44:12.339 00:44:12.349 heat exchange surface to volume ratio is
00:44:15.370 00:44:15.380 very high so that is the way it is
00:44:17.229 00:44:17.239 compact on the other hand disadvantage
00:44:19.989 00:44:19.999 sight it is a narrow size of the flow
00:44:22.180 00:44:22.190 channels results in high pressure drop
00:44:24.759 00:44:24.769 and limits is used to only low viscosity
00:44:28.390 00:44:28.400 fluids which does not contain large
00:44:32.019 00:44:32.029 suspended particulates this is the
00:44:34.259 00:44:34.269 disadvantage and also their need for
00:44:36.609 00:44:36.619 gaskets gaskets in the sense so here if
00:44:39.759 00:44:39.769 you see in this so this is nothing but
00:44:42.099 00:44:42.109 an gaskets okay so which prevents the
00:44:46.719 00:44:46.729 further leaking of the fluid right so
00:44:50.259 00:44:50.269 the need for gaskets is very much
00:44:52.809 00:44:52.819 disadvantageous one as I discussed there
00:44:55.569 00:44:55.579 are many improvements made in these kind
00:44:58.299 00:44:58.309 of heat exchanges for example there is
00:45:00.699 00:45:00.709 something called double plate security
00:45:02.890 00:45:02.900 system so that means the both the plates
00:45:05.170 00:45:05.180 where welded and formed as a channel
00:45:07.779 00:45:07.789 then after that these formed channels
00:45:10.539 00:45:10.549 where further made together in the
00:45:13.870 00:45:13.880 module by gaskets right so if there is
00:45:17.469 00:45:17.479 any leakage between the plates then
00:45:20.499 00:45:20.509 obvious
00:45:21.109 00:45:21.119 it is known because it is kept as a
00:45:23.089 00:45:23.099 channel so in that way the security
00:45:26.299 00:45:26.309 system can be improved to avoid the
00:45:29.450 00:45:29.460 leakage of the liquid foot product when
00:45:33.200 00:45:33.210 it is heated so there are many
00:45:35.509 00:45:35.519 improvements and also I say served
00:45:38.660 00:45:38.670 earlier so all to be performed in the
00:45:41.200 00:45:41.210 contamination free area so that one has
00:45:43.940 00:45:43.950 to ensure while using any of the heat
00:45:46.609 00:45:46.619 exchange equipment in the food
00:45:48.529 00:45:48.539 processing industry so that sulphur heat
00:45:53.059 00:45:53.069 exchanges so these are the references
00:45:55.700 00:45:55.710 and additional resources what I have
00:45:57.739 00:45:57.749 used in this particular lecture thank
00:46:00.559 00:46:00.569 00:46:01.230 00:46:01.240 00:46:23.840 00:46:23.850
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